CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Japanese Priority Patent Application JP
2014-250978 filed December 11, 2014, the entire contents of which are incorporated
herein by reference.
Technical Field
[0002] The present disclosure relates to a communication control device, a radio commu
nication device, a communication control method, and a radio communication method.
Background Art
[0003] The radio communication environment has been facing the problem of radically in
creasing data traffic in recent years. For this reason, as one of radio access technologies
(RATs) of the fifth mobile communication scheme (5G), a multiplexed/multiple access
scheme that uses superposition coding (SPC) has gained attention. Thus, SPC and tech
nologies based on the scheme have been developed.
[0004] For example, PTL 1 and PTL 2 mentioned below disclose a technology in which,
when a digital modulation symbol that is a complex number is multiplexed using a
method corresponding to SPC, amplitude or electric power which can enable the mul
tiplexed symbol to be appropriately demodulated or decoded in a reception device is
set.
[0005] In addition, PTL 3 mentioned below discloses a technology relating to highly
improving a successive interference canceller (SIC) on a reception device side for
receiving signals that are multiplexed using SPC or non-orthogonally multiplexed
using another method.
Citation List
Patent Literature
[0006] PTL 1: JP 2003-78419A
PTL 2: JP 2003-229835A
PTL 3: JP 2013-2475 13A
Summary
Technical Problem
[0007] In the field of the present technology, however, further improvement in performance
has been demanded. Thus, the present disclosure proposes a novel and improved com
munication control device, radio communication device, communication control
method, and radio communication method which can realize communication in which
orthogonal resources and non-orthogonal resources are selectively used.
Solution to Problem
[0008] According to an embodiment of the present disclosure, there is provided a commu
nication control device including: a communication unit configured to perform com
munication with a radio communication device of a radio communication system in
which communication is possible using a plurality of access schemes including at least
one of the access schemes of a multiple access scheme that uses orthogonal resources
and a multiple access scheme that uses non-orthogonal resources; and a control unit
configured to perform allocation of resources relating to the access schemes to be used
by the radio communication device.
[0009] According to an embodiment of the present disclosure, there is provided a radio com
munication device including: a radio communication unit configured to perform radio
communication using one or more access schemes of at least either a multiple access
scheme that uses orthogonal resources or a multiple access scheme that uses nonorthogonal
resources; and a control unit configured to control the radio communication
unit to perform radio communication using allocated resources for the access schemes
to be used by the radio communication unit.
[0010] According to an embodiment of the present disclosure, there is provided a commu
nication control method including: performing communication with a radio commu
nication device of a radio communication system in which communication is possible
using a plurality of access schemes including at least one of the access schemes of a
multiple access scheme that uses orthogonal resources and a multiple access scheme
that uses non-orthogonal resources; and performing allocation of resources relating to
the access schemes to be used by the radio communication device with a processor.
[001 1] According to an embodiment of the present disclosure, there is provided a radio com
munication method including: performing radio communication using one or more
access schemes of at least either a multiple access scheme that uses orthogonal
resources or a multiple access scheme that uses non-orthogonal resources; and con
trolling, with a processor, the radio communication to be performed using allocated
resources for the access schemes to be used during the radio communication.
Advantageous Effects of Invention
[0012] According to one or more of the present disclosure described above, communication
in which orthogonal resources and non-orthogonal resources are selectively used can
be realized. Note that the effects described above are not necessarily limited, and along
with or instead of the effects, any effect that is desired to be introduced in the present
specification or other effects that can be expected from the present specification may
be exhibited.
Brief Description of Drawings
[fig.l]FIG. 1 is a diagram for describing an example of allocation of resources in an or
thogonal multiple access scheme.
[fig.2]FIG. 2 is a diagram for describing an example of allocation of resources in a
non- orthogonal multiple access scheme.
[fig.3]FIG. 3 is a diagram for describing an example of a configuration of a commu
nication system according to an embodiment.
[fig.4]FIG. 4 is a diagram for describing a logical interface and a physical interface.
[fig.5]FIG. 5 is a diagram for describing an example of another configuration of the
communication system according to the embodiment.
[fig.6]FIG. 6 is a block diagram illustrating an example of a logical configuration of a
communication control device according to the embodiment.
[fig.7]FIG. 7 is a block diagram illustrating an example of a logical configuration of a
base station according to the embodiment.
[fig.8]FIG. 8 is a block diagram illustrating an example of a logical configuration of a
terminal device according to the embodiment.
[fig.9]FIG. 9 is a flowchart showing an example of the flow of an allocation process of
an access setting executed in the communication control device according to the em
bodiment.
[fig. 10]FIG. 10 is a sequence diagram showing an example of the flow of an allocation
process executed in the communication system according to the embodiment
[fig. 11]FIG. 11 is a block diagram illustrating a functional configuration of a
transmission device according to the embodiment.
[fig. 12]FIG. 12 is a block diagram illustrating a functional configuration of a
transmission device according to the embodiment.
[fig.l3]FIG. 13 is a block diagram illustrating a functional configuration of a
transmission device according to the embodiment.
[fig. 14]FIG. 14 is a block diagram illustrating a functional configuration of a
transmission device according to the embodiment.
[fig.l5]FIG. 15 is a flowchart showing an example of the flow of an allocation process
of an access setting executed by the communication control device according to the
embodiment.
[fig.l6]FIG. 16 is a flowchart showing an example of the flow of an FDM employment
determination process executed in the communication control device according to the
embodiment.
[fig.l7]FIG. 17 is a flowchart showing an example of the flow of an SDMA em
ployment determination process executed in the communication control device
according to the embodiment.
[fig.l8]FIG. 18 is a flowchart showing an example of the flow of an SPC employment
determination process executed in the communication control device according to the
embodiment.
[fig. 19]FIG. 19 is a flowchart showing an example of the flow of an IDMA em
ployment determination process executed in the communication control device
according to the embodiment.
[fig.20]FIG. 20 is a flowchart showing an example of the flow of an RSMA em
ployment determination process executed in the communication control device
according to the embodiment.
[fig.21]FIG. 2 1 is a flowchart showing an example of the flow of an SCMA em
ployment determination process executed in the communication control device
according to the embodiment.
[fig.22]FIG. 22 is a sequence diagram showing an example of the flow of an access
setting information notification process in the communication system according to the
embodiment.
[fig.23]FIG. 23 is a sequence diagram showing an example of the flow of an access
setting information notification process in the communication system according to the
embodiment.
[fig.24]FIG. 24 is a flowchart showing an example of the flow of an access setting in
formation reception process executed by the terminal device according to the em
bodiment.
[fig.25]FIG. 25 is a flowchart showing an example of the flow of an access setting in
formation reception process executed by the terminal device according to the em
bodiment.
[fig.26]FIG. 26 is an explanatory diagram for describing an access setting information
notification process according to the embodiment.
[fig.27]FIG. 27 is a flowchart showing an example of the flow of an access setting in
formation reception process executed by the terminal device according to the em
bodiment.
[fig.28]FIG. 28 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the embodiment.
[fig.29]FIG. 29 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the embodiment.
[fig.30]FIG. 30 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the embodiment.
[fig.31]FIG. 3 1 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the embodiment.
[fig.32]FIG. 32 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the embodiment.
[fig.33]FIG. 33 is a sequence diagram showing an example of the flow of a capability
information notification process executed in the communication system according to
the embodiment.
[fig.34]FIG. 34 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment.
[fig.35]FIG. 35 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment.
[fig.36]FIG. 36 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment.
[fig.37]FIG. 37 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment.
[fig.38]FIG. 38 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment
[fig.39]FIG. 39 is a sequence diagram showing an example of the flow of a handover
process executed in the communication system according to the embodiment.
[fig.40]FIG. 40 is a flowchart showing an example of the flow of a capability in
formation confirmation process executed in the communication control device
according to the embodiment.
[fig.41]FIG. 4 1 is a flowchart showing an example of the flow of an admission control
process executed in the base station according to the embodiment.
[fig.42]FIG. 42 is a block diagram illustrating an example of a schematic configuration
of a server.
[fig.43]FIG. 43 is a block diagram illustrating a first example of a schematic con
figuration of an eNB.
[fig.44]FIG. 44 is a block diagram illustrating a second example of the schematic con
figuration of the eNB.
[fig.45]FIG. 45 is a block diagram illustrating an example of a schematic configuration
of a smartphone.
[fig.46]FIG. 46 is a block diagram illustrating an example of a schematic configuration
of a car navigation device.
Description of Embodiments
Hereinafter, preferred embodiments of the present disclosure will be described in
detail with reference to the appended drawings. Note that, in this specification and the
appended drawings, structural elements that have substantially the same function and
structure are denoted with the same reference numerals, and repeated explanation of
these structural elements is omitted.
[0015] Also, in this specification and the appended drawings, elements having substantially
the same function and structure may in some cases be distinguished by different letters
appended to the same sign. For example, multiple elements having substantially the
same function and structure are distinguished as base stations 200A, 200B, 200C, and
so on as appropriate. On the other hand, when not particularly distinguishing each of
multiple elements having substantially the same function and structure, only the same
sign will be given. For example, the base stations 200A, 200B, 200C will be simply
designated as the base station 200 when not being particularly distinguished.
[0016] Note that description will be provided in the following order.
1. Introduction
2. Configuration examples
2.1. Communication system
2.2. Communication control device
2.3. Base station
2.4. Terminal device
3. Details of functions
3.1. Overview of an access setting allocation process
3.2. Transmitting function and receiving function
3.3. Details of an allocation process of an access setting
3.4. Notification of access setting information
3.5. Channel configuration
3.6. Capability information
4. Application examples
5. Conclusion
[0017] <1. Introduction>
First, a technology relating to SPC will be described with reference to FIGS. 1 and 2.
FIGS. 1 and 2 are illustrative diagrams for describing the technology relating to SPC.
[0018] As one of 5G radio access technologies (RATs), a non-orthogonal multiple access
scheme has drawn attention as a successor to Long Term Evolution (LTE) and LTEAdvanced
(LTE-A).
[0019] In orthogonal frequency division multiple access (OFDMA) or single-carrier FDMA
(SC-FDMA) employed in LTE, resources are allocated not to overlap among user
terminals within a cell. Note that resources in OFDMA or SC-FDMA refer to
frequency resources or time resources for radio communication, and include various
types such as subcarriers, subframes, resource blocks, and resource elements. Such a
RAT in which resources are allocated not to overlap is also called an orthogonal
multiple access scheme.
[0020] FIG. 1 is a diagram for describing an example of allocation of resources in the or
thogonal multiple access scheme. In FIG. 1, the horizontal axis represents frequencies,
and resources allocated to users are depicted in different colors according to the users.
As illustrated in FIG. 1, in the orthogonal multiple access scheme, different resource
blocks (RBs) can be allocated to the users in, for example, the frequency direction.
[0021] On the other hand, in the non-orthogonal multiple access scheme, at least an
overlapping part of resources is allocated to user terminals within a cell. When the
non-orthogonal multiple access scheme is employed, signals that are transmitted and
received by user terminals within a cell can interfere with each other in a radio space.
A reception side, however, can acquire information of each user through a prede
termined decoding process. Thus, it is known theoretically that the non-orthogonal
multiple access scheme can achieve a higher communication capacity (or cell commu
nication capacity) than the orthogonal multiple access scheme when proper allocation
of resources is executed.
[0022] FIG. 2 is a diagram for describing an example of allocation of resources in the nonorthogonal
multiple access scheme. In FIG. 2, the horizontal axis represents fre
quencies, and resources allocated to users are depicted in different colors according to
the users. As illustrated in FIG. 2, in the non-orthogonal multiple access scheme,
resource blocks, for example, overlapping in the frequency direction can be allocated
to users. Note that such allocation is performed in, for example, code division multiple
access (CDMA) or interleave-division multiple access (IDMA).
[0023] As one RAT classified as the non-orthogonal multiple access scheme, a multiplexed/
multiple access using SPC is exemplified. In SPC, a transmission side causes at least a
part of frequency resources or time resources to overlap while allocating different
electric power levels to signals to be multiplexed. A reception side receives and
decodes a signal multiplexed on the same frequency resources or time resources using
a mechanism such as an SIC or iterative detection.
[0024] Here, when efficient scheduling of a plurality of users is attempted using SPC, a
constraint is assumed to be imposed on the relation of path loss between a base station
and the plurality of users and the positional relation between the base station and the
plurality of users, particularly in downlink. For example, when multiplexing respective
signals of two users using SPC is considered, in order to efficiently operate an SIC on
a reception device side, electric power of the respective two symbols multiplexed using
SPC is supposed to be set according to the difference in their path loss. To maintain
this setting, it is necessary to perform SPC multiplexing by intentionally applying a
power difference to the users who have substantially the same path loss. In such a case,
there is concern of unfairness between the users. Thus, in order to overcome such un
fairness, more complicated scheduling is desirable.
[0025] In addition, when SPC and another non-orthogonal multiplexing scheme are
employed, it is desirable to exchange information of non-orthogonal multiplexing
scheme or scheduling that has been used between communication devices. Here, when
a general method of physically disposing control channels and data channels, i.e., a
method of disposing the channels by causing them to be orthogonal to each other in the
frequency and time directions, is employed, there is a possibility of the channels
having deteriorating efficiency. In addition, in order to simultaneously accommodate a
device that is compatible with the non-orthogonal multiplexing scheme and a device
that is not (so-called legacy device), it is desirable to provide a control channel that can
be properly decoded to the legacy device.
[0026] In addition, in a general cellular system, selecting a multiplexing scheme to be used
from a plurality of multiplexing schemes and switching one are not considered at the
time of handover. On the other hand, when handover is executed in a system operated
while selecting a multiplexing scheme to be used from a plurality of non-orthogonal
multiplexing schemes, information of an orthogonal multiplexing scheme or nonorthogonal
multiplexing scheme that is being employed or can be employed by a
handover destination is used. Thus, it is desirable to provide the procedure of handover
using such information in order to improve efficiency of the system that employs the
plurality of non-orthogonal multiplexing schemes.
[0027] Therefore, a communication system according to an embodiment of the present
disclosure has been created focusing on the above-described circumstances. The com
munication system according to an embodiment of the present disclosure can realize
communication in which orthogonal resources and non-orthogonal resources can be se
lectively used. More specifically, the communication system according to the em
bodiment can communicate using a plurality of access schemes including at least one
of the access schemes of a multiple access scheme that uses orthogonal resources and a
multiple access scheme that uses non-orthogonal resources. In addition, the commu
nication system according to the embodiment can properly perform allocation of an
access scheme and resources that each radio communication device uses. Details of the
embodiment will be described below.
[0028] <2. Configuration examples>
<2.1. Communication system>
First, an overall configuration of the communication system according to the em
bodiment will be described with reference to FIGS. 3 to 5.
[0029] FIG. 3 is a diagram for describing an example of the configuration of the communication
system according to the embodiment. As illustrated in FIG. 3, the commu
nication system 1 includes an application server 10, a service platform 11, a network
gateway 12, a device 13, an IP network 14, and a core network 15.
[0030] The application server 10 is a server which provides a service. The service platform
11 is a server which provides an environment that is the foundation of the service
provided by the application server 10. The network gateway 12 is a device with a
function of intermediating different networks. The device 13 is a radio communication
device. The network gateway 12 is connected to the service platform 11 via the IP
network 14. In addition, the device 13 is connected to the network gateway 12 via the
core network 15.
[0031] The device 13 can include a terminal device, a base station, a network manager, or
the like. The terminal device is, for example, a user terminal. The base station is, for
example, a NodeB, an eNB, an access point, or the like. The network manager has a
function of managing a network. Although the terminal device, the base station, and
the network manager are expressed in the same layer as the device 13 in FIG. 3, they
may belong to different layers. When they belong to different layers, it is desirable that
the layer to which the base station and the network manager belong be closer to the
core network 15 than the layer to which the terminal device belongs.
[0032] The terminal device that belongs to the device 13 uses the service provided by the
application server 10 through a network. A logical session relating to use of the service
can be understood as communication between the terminal device and the application
server 10 denoted by reference numeral 21. On the other hand, physical sessions
relating to the user of the service can be understood as communication performed with
the variety of devices as denoted by reference numerals 22, 23, and 24. For example,
the terminal device accesses the application server 10 via the base station, the core
network 15, the network gateway 12, the IP network 14, and the service platform 11.
Note that the application server 10 may form the service platform 11 together with a
plurality of other servers, for example, cloud systems. In this case, the service platform
11 may have a gateway function of connecting to the IP network 14. In addition, the
service platform 11, the IP network 14, and the core network 15 can further include a
router, a switch, a virtualization device which virtualizes a network such as a router or
a switch, a virtualization control device which controls virtualization, a cable, and the
like as physical devices.
[0033] FIG. 4 is a diagram for describing a logical interface and a physical interface. As il
lustrated in FIG. 4, base stations 13A and 13B are connected to each other through a
logical interface 25. This interface is not limited to being logically connected. For
example, the base stations 13A and 13B can be physically connected to each other
through a physical interface 26 which includes a plurality of entities such as the core
network 15 as illustrated in FIG. 4. Note that the interfaces between the base stations
denoted by reference numerals 25 and 26 are also referred to as X2 interfaces.
[0034] FIG. 5 is a diagram for describing an example of another configuration of the com
munication system according to the embodiment. In FIG. 5, a network configuration in
Machine Type Communications (MTC) that is another example of a network con
figuration is illustrated. Note that the dashed lines in the drawing represent a control
plane and the solid lines represent a user plane. In addition, the entities and paths in the
drawing (control plane and user plane) are respectively logical entities and logical
paths.
[0035] The network configuration illustrated in FIG. 5 is broadly divided into a home public
land mobile network (HPLMN) and a visited public land mobile network (VPLMN),
showing a configuration in which roaming of different communication service
providers is used. The HPLMN is a network of the communication service provider to
which a target communication device (for example, UE 31) originally belongs, and the
VPLMN is a network of a roaming destination of the communication device. A public
IP network may relay the HPLMN and the VPLMN. During roaming, data of the
control plane is in particular relayed from the VPLMN to entities within the HPLMN
as illustrated in FIG. 5. This is because it is necessary for control information of the
target UE 3 1 to be managed on the communication service provider in the home
ground. On the other hand, data of the user plane is relayed from the gateway on the
VPLMN side to the gateway of the HPLMN side, and then relayed and transferred to
an application server 41. Note that the data of the user plane may go through the public
IP network or an entity of the service platform. In normal circumstances in which
roaming does not occur, there is no interface between the HPLMN and the VPLMN.
[0036] Each of the entities included in the network configuration shown in FIG. 5 will be
described in order below.
[0037] The user equipment (UE) 3 1 is an example of a terminal device 300, in which an
"MTC UE Application" that is an application for MTC is installed. The UE 3 1 accesses
an MME 33, an S-GW 34, an SGSN 36, and an MSC 37 via a radio access network
(RAN) 32. In the present embodiment, the RAN 32, a plurality of access schemes
including at least one of the access schemes of a multiple access scheme using or
thogonal resources and a multiple access scheme using non-orthogonal resources can
be used. A base station 200 resides in, for example, the RAN 32, and is connected to
the UE 31.
[0038] The Mobility Management Entity (MME) 33 is an entity that mainly deals with the
control plane, and manages mobility and security of the UE 31. When the UE 3 1
moves to an area of handover or the like using mobility, the MME 33 manages in
formation of the movement, and exchanges the information with a superordinate entity
of the core network or an entity of another operator.
[0039] The Serving Gateway (S-GW) 34 mainly deals with data of the user plane (IP data).
The S-GW 34 is an entity that interconnects the RAN 32 and the core network, and is
in charge of routing of data while coping with mobility of each UE.
[0040] A Packet Data Network Gateway (P-GW) 35 mainly deals with data of the user plane
(IP data). The P-GW 35 is an entity that interconnects the core network and an external
network. In addition, the P-GW 35 also performs policy control, charge control, and
management of IP addresses of the core network and a RAN to be provided. The SGW
34 and the P-GW 35 are logically different entities, but may be the same
physically. The gateway GPRS support node (GGSN) 35 is an entity that interconnects
the core network and an external network, like the P-GW 35.
[0041] The serving GPRS support node (SGSN) 36 is an entity that functions as both the
MME 33 and the S-GW 34. The SGSN 36 is an entity residing according to the type of
network (general packet radio services (GPRS)) or the type of RAN 32 (WCDMA (a
registered trademark)/GMS)). Because it functions as both the MME 33 and the S-GW
34, the SGSN 36 deals with both the control plane and the user plane.
[0042] The mobile switching centre (MSC) 37 is an entity that is mainly used on a network
of GSM (a registered trademark) and WCDMA, and is in charge of delivering circuit
switch (CS) services such as voice calls, short message services (SMS), and the like. In
order to support the CS services, the MSC 37 has a function of controlling installation
and release of end-to-end connection, mobility of the UE 31, handover during calling,
and the like.
[0043] A Home Subscriber Server (HSS) 38 is a subscriber information database relating to
contractors and users (for example, the UE 31) with which an operator has entered into
a contract. The HSS 38 manages information, for example, authentication information,
current residence, and the like. When the UE 3 1 performs roaming, being present in a
roaming destination is also managed by the HSS 38.
[0044] MTC-Authentication, Authorization, and Accounting (AAA) 39 is an entity which
provides authentication, authorization, and accounting functions. The MTC-AAA 39
deals with functions and control with respect to each subscriber or UE 3 1 using the
subscriber information retained in the HSS 38.
[0045] A Charging Data Function (CDF) 40 and a Charging Gateway Function (CGF) 40
are entities for transmitting and receiving billing data with respect to a billing
processing domain (Billing Center/Billing Domain) of the operator.
[0046] The application server 4 1 is a server for providing services. A Services Capability
Server (SCS) 42 is an entity for properly selecting a service that the application server
4 1 can provide. For example, a case in which, before the application server 4 1 provides
a certain service, it is necessary for a target UE 3 1 to monitor or sense the service is
assumed. In this case, when the SCS 42 request a trigger thereof from the UE 31, the
application server 4 1 can start providing a service smoothly. The SCS 42 is not
necessary for all application servers 41. There may be, for example, an application
server 4 1A that is accompanied with the SCS 42 and an application server 4 IB that is
not, as illustrated in FIG. 5. Note that the application server 4 1A that is accompanied
with the SCS 42 is also called an indirect model, and the application server 4 IB that is
not accompanied with the SCS 42 is also called a direct model. In addition, a network
configuration which includes both of them is also called a hybrid model.
[0047] An MTC-Interworking Function (IWF) 43 is an entity which is connected to one or
more SCSs 42. The MTC-IWF 43 has a function of determining or authorizing whether
an application (service) provided via the SCS 42 can be provided on a network of a
corresponding operator. In addition, the MTC-IWF also plays roles of receiving a
request for a trigger for a user transferred from the SCS 42 and replying to the SCS 42
with the result of the trigger.
[0048] A Short Message Entity (SME) 44 is an entity which performs transmission or
reception of short messages.
[0049] A Short Message Service Switching Centre (SMS-SC) 45, an SMS-Gateway Mobile
Switching Centre (SMS-GMSC) 45, and an SMS-Interworking Mobile Switching
Centre (SMS-IWMSC) 45 are entities which control exchange of short messages on
the HPLMN. The SMS-SC 45, SMS-GMSC 45, and SMS-IWMSC 45 are in charge of
notifying relevant entities of a setting when there is no user who transmits or receives a
short message, or success of transmission or reception of a short message.
[0050] An IP Short Message Gateway (IP-SM-GW) 46 is an entity that has a function of
taking in SMSs of an external IP Network (a service, a service provider/ or the like), in
addition to SMSs provided by an operator for improving convenience of SMSs.
[0051] The overall configuration of the communication system 1 according to the present
embodiment has been described above. Next, basic configuration examples of the r e
spective devices that the communication system 1 includes will be described.
[0052] <2.2 Communication control device>
The communication system 1 according to the present embodiment includes a com
munication control device which controls communication performed within the com
munication system 1 coordinately. The communication control device can be realized
as, for example, the application server 10, the service platform 11, or the network
manager 16. The communication control device may be realized as a logical entity, or
may be integrally formed with a base station.
[0053] FIG. 6 is a block diagram illustrating an example of a logical configuration of a com
munication control device 100 according to the present embodiment. As illustrated in
FIG. 6, the communication control device 100 includes a communication unit 110, a
storage unit 120, and a control unit 130.
[0054] (1) Communication unit 110
The communication unit 110 is a communication interface which intermediates com
munication of the communication control device 100 with another device. The commu
nication unit 110 may be a wired communication interface or a wireless commu
nication interface. The communication unit 110 according to the present embodiment
communicates with a communicable radio communication device of the commu
nication system 1 using a plurality of access schemes including at least one of the
access schemes of a multiple access scheme that uses orthogonal resources and a
multiple access scheme that uses non-orthogonal resources. As the radio commu
nication device with which the communication unit 110 communicates, for example,
one or more terminal devices which belong to the device 13 and one or more base
stations are exemplified.
[0055] In the present embodiment, orthogonal resources or non-orthogonal resources are
used for multiplexing difference users or signals. As orthogonal resources, for
example, time (a subframe, a slot, a radio frame, and the like), a frequency (a
component carrier, a subcarrier, a subchannel, a resource block, and the like), a code (a
spread code, a randomized code, and the like), and the like are exemplified. In
addition, as non-orthogonal resources, a space (a spatial stream, a spatial layer, a
spatial code book, an antenna, an antenna port, and the like), electric power (power and
the like), an interleaver (a bit interleaver, a symbol interleaver, and the like), a data
rate, a code (a sparse code, a spread codebook, and the like), and the like are ex
emplified. Although such resources are referred to simply as resources in the present
specification, they may be referred to as other various names. For example, the
resources may be referred to as radio access resources (RAR), radio resources (RR),
access resources (AR), radio access axes (RAA), radio access components (RAC), or
radio access blocks (RAB).
[0056] The communication unit 110 directly or indirectly communicates with the base
station 200 and the terminal device 300. For example, the communication unit 110
may transmit access setting information to be described below to the base station 200
or the terminal device 300. The communication unit 110 receives capability in
formation from the base station 200 or the terminal device 300. In addition, the com
munication unit 110 may transfer the received capability information to another device
such as another communication control device 100 or the like. The capability in
formation is information indicating with which access scheme each device is
compatible or incompatible, and with which resources each device is compatible or in
compatible. That is to say, the capability information includes information indicating
compatibility with non-orthogonal resources. In addition, the capability information
includes information indicating compatibility with orthogonal resources.
[0057] In addition, the communication unit 110 transmits information indicating a result of
allocation by the control unit 130 to be described below to the base station 200 or the
terminal device 300. The information indicating a result of allocation by the control
unit 130 includes information indicating at least any of allocated access scheme or
resources. The information indicating the result of allocation is also referred to as
access setting information below.
[0058] (2) Storage unit 120
The storage unit 120 stores a program and data for operating the communication
control device 100 using a storage medium such as a hard disk or a semiconductor
memory. The data stored by the storage unit 120 can include, for example, capability
information of each device within the communication system 1 (for example, the base
station 200, the terminal device 300, and the like).
[0059] (3) Control unit 130
The control unit 130 controls overall operations of the communication control device
100. The control unit 130 has a function of controlling communication performed
within the communication system 1 coordinately.
[0060] For example, the control unit 130 has a function of allocating resources relating to an
access scheme that a radio communication device within the communication system 1
uses. Resources to be allocated by the control unit 130 include at least one of a space
area, an electric power area, an interleaver area, a data rate area, and a sparse code
area. In addition, resources to be allocated may include a time area or a frequency area.
For example, the control unit 130 first allocates an access scheme to be used by each
radio communication device. Then, the control unit 130 allocates a space area, an
electric power area, an interleaver area, a data rate area, or a sparse code area to be
used in the allocated access scheme to the radio communication device. For example,
the control unit 130 performs allocation based on capability information of each device
within the communication system 1. In addition, the control unit 130 may perform al
location further based on status information of the base station 200 within the commu
nication system 1. The status information is information indicating which access
scheme the base station 200 itself is currently using. A combination of an access
scheme and resources will also be referred to as an access setting and allocation of an
access scheme and resources will also be referred to as allocation of an access setting
below. The control unit 130 may allocate different access settings or may allocate a
shared access setting to one or more base stations 200 or one or more terminal devices
300.
[0061] The control unit 130 can perform various processes using the capability information
or the status information. For example, the control unit 130 can use the capability information
and the status information in the procedure of handover or the procedure of
admission control. For example, the control unit 130 may change an access setting to
be allocated to the base station 200 or the terminal device 300 in the procedure of
handover or the procedure of admission control.
[0062] <2.3. Base station>
FIG. 7 is a block diagram illustrating an example of a logical configuration of the
base station 200 according to the present embodiment. As illustrated in FIG. 7, the
base station 200 includes a radio communication unit 210, a network communication
unit 220, a storage unit 230, and a control unit 240.
[0063] (1) Radio communication unit 210
The radio communication unit 210 is a communication interface which intermediates
communication of the base station 200 with another device. The radio communication
unit 210 according to the present embodiment performs radio communication with one
or more terminal devices 300 that access the base station 200 using a plurality of
access schemes including at least one of the access schemes of a multiple access
scheme that uses orthogonal resources and a multiple access scheme that uses nonorthogonal
resources. For example, the radio communication unit 210 performs radio
communication with the terminal device 300 using an access setting allocated by the
communication control device 100. For example, the radio communication unit 210
receives capability information from the terminal device 300. In addition, the radio
communication unit 210 transmits access setting information received from the com
munication control device 100 using the network communication unit 220 to the
terminal device 300.
[0064] (2) Network communication unit 220
The network communication unit 220 is a communication interface for connecting
the base station 200 to the core network 15. The network communication unit 220 may
be a wired communication interface or a wireless communication interface. The
network communication unit 220 transmits and receives data traffic and exchanges
control messages to and from various control nodes on the core network 15. The
network communication unit 220 can communicate with another base station 200 or
communication control device 100 within the communication system 1.
[0065] For example, the network communication unit 220 may transfer capability in
formation received from the terminal device 300 using the radio communication unit
210 to another device such as another base station 200 or communication control
device 100. In addition, the network communication unit 220 may transmit status in
formation indicating which access scheme the base station 200 itself is currently using
to another base station 200 or communication control device 100. In addition, the
network communication unit 220 receives access setting information indicating an
access setting allocated by the communication control device 100 from the commu
nication control device 100.
[0066] (3) Storage unit 230
The storage unit 230 stores a program and data for operating the base station 200
using a storage medium such as a hard disk or a semiconductor memory. The data
stored by the storage unit 230 can include access setting information and capability in
formation or one or more terminal devices 300 that accesses the base station 200.
[0067] (4) Control unit 240
The control unit 240 controls overall operations of the base station 200. The control
unit 240 according to the present embodiment has a function of controlling the radio
communication unit 210 to perform radio communication using resources allocated
with regard to an access scheme that the radio communication unit 210 uses. For
example, the control unit 240 sets the radio communication unit 210 to use the access
scheme allocated by the communication control device 100. Then, the control unit 240
sets the radio communication unit 210 to perform radio communication using the space
area, the electric power area, the interleaver area, the data rate area, or the sparse code
area allocated by the communication control device 100 with respect to the access
scheme to be used by the radio communication unit 210.
[0068] The control unit 240 can perform various processes using capability information or
status information. For example, the control unit 240 can use capability information or
status information in the procedure of handover or the procedure of admission control.
For example, the control unit 240 may apply a change in an access setting instructed by
the communication control device 100 to the procedure of handover or the procedure
of admission control. At this time, the control unit 240 may perform change possibility
determination for determining whether to apply or reject the change of the instructed
access setting. In addition, the control unit 240 may determine whether to approve or
reject acceptance of handover of the terminal device 300 according to the result of the
change possibility determination on the access setting.
[0069] <2.4. Terminal device>
FIG. 8 is a block diagram illustrating an example of a logical configuration of the
terminal device 300 according to the present embodiment. As illustrated in FIG. 8, the
terminal device 300 has a radio communication unit 310, a storage unit 320, and a
control unit 330.
[0070] (1) Radio communication unit 310
The radio communication unit 310 is a radio communication interface which inter
mediates radio communication of the terminal device 300 with another device. The
radio communication unit 310 according to the present embodiment performs radio
communication using one or more access schemes of at least either a multiple access
scheme that uses orthogonal resources or a multiple access scheme that uses nonorthogonal
resources. For example, the radio communication unit 310 performs radio
communication with the base station 200 using an access setting allocated by the com
munication control device 100. For example, the radio communication unit 310
transmits its capability information to the base station 200.
[007 1] (2) Storage unit 320
The storage unit 320 stores a program and data for operating the terminal device 300
using a storage medium such as a hard disk or a semiconductor memory. The data
stored by the storage unit 320 can include access setting information.
[0072] (3) Control unit 330
The control unit 330 controls overall operations of the terminal device 300. The
control unit 330 according to the present embodiment has a function of controlling the
radio communication unit 310 to perform radio communication using resources
allocated with regard to an access scheme that the radio communication unit 310 uses.
For example, the control unit 330 sets the radio communication unit 310 to use the
access scheme allocated by the communication control device 100. Then, the control
unit 330 sets the radio communication unit 310 to perform radio communication using
the space area, the electric power area, the interleaver area, the data rate area, or the
sparse code area allocated by the communication control device 100 with respect to the
access scheme to be used by the radio communication unit 310.
[0073] The basic configuration example of each of the devices included in the commu
nication system 1 has been described above. Next, the functions of the devices will be
described in detail.
[0074] <3. Details of functions>
<3.1. Overview of an access setting allocation process>
FIG. 9 is a flowchart showing an example of the flow of an allocation process of an
access setting executed in the communication control device 100 according to the
present embodiment.
[0075] As shown in FIG. 9, first, the control unit 130 ascertains capability information of
each of the devices included in the communication system 1 in Step S102. For
example, the communication unit 110 receives capability information from one or
more base stations 200 and one or more terminal devices 300 included in the commu
nication system 1. Then, the control unit 130 checks with which access scheme each
device is compatible or incompatible and with which resources each device is
compatible or incompatible with reference to capability information.
[0076] Next, in Step S104, the control unit 130 checks desired communication quality. For
example, the control unit 130 checks demanded or necessary communication quality of
such as a throughput, a data rate, or an amount of delay. For this reason, the base
station 200 or the terminal device 300 transmits information indicating demanded com
munication quality to the communication control device 100.
[0077] Next, in Step S106, the control unit 130 checks a state of a communication path
(radio propagation path). For example, the control unit 130 may check a state of path
loss, a state of fading between each transmission and reception antenna pairs in the
configuration of a plurality of antennas relating to multi-input multi-output (MIMO), a
signal-to-interference-plus-noise power ratio (SINR), or the like. In addition, the
control unit 130 may check a signal-to-noise ratio (SNR), the number of spatial layers
transferable on a radio propagation path between transmission and reception devices
(which corresponds to the rank of a MIMO channel matrix), a proper precoding matrix,
a proper modulation and demodulation scheme/error-correction coding rate, and the
like.
[0078] Next, the control unit 130 decides an access route in Step S108.
[0079] Then, in Step SI 10, the control unit 130 performs allocation of an access setting. For
example, the control unit 130 performs the access setting based on the processing
result of the above-described Steps S102 to S108. Note that the control unit 130 may
allocate a shared access setting to one or more terminal devices 300 that access one or
more cells formed by the base station 200. At this time, the control unit 130 may also
allocate an access setting shared by each cell, or allocate an access setting shared by
each base station 200. In these cases, the terminal devices 300 within the cells or under
the base stations 200 can use the same access setting within the same cells or under the
same base stations 200, or at least some of them can use the same access setting. In
addition, the control unit 130 may allocate an access setting to each terminal device
300. In this case, the control unit 130 can allocate a proper access setting to each
terminal device 300. The cells or the base stations 200 perform scheduling or the like
taking access settings used by each terminal device 300 into consideration.
[0080] Next, in Step SI 12, the control unit 130 performs a resetting of a network. For
example, the control unit 130 transmits access setting information indicating the al
location result of the above-described Step SI 10 to each of devices within the commu
nication system 1. Accordingly, communication according to the access setting in
formation is started between the devices within the communication system 1.
[0081] Next, in Step SI 14, the control unit 130 determines whether or not communication of
each device has ended. When it is determined that the communication continues (No in
SI 14), the process returns to Step S104 again, and the above-described processes are
repeated. The above-described processes may be periodically repeated at a prede
termined interval. Accordingly, the control unit 130 can allocate access settings again
according to passage of time. On the other hand, when it is determined to have ended
(Yes in Step SI 14), the process ends.
[0082] Next, an operation processing example of the entire communication system 1 corre
sponding to the allocation process of an access setting by the communication control
device 100 shown in FIG. 9 will be described.
[0083] FIG. 10 is a sequence diagram showing an example of the flow of an allocation
process executed in the communication system 1 according to the present embodiment.
A terminal device 300A, a base station 200A, a network manager 16A, a network
gateway 12A, a terminal device 300B, a base station 200B, a network manager 16B, a
network gateway 12B, the service platform 11, and the application server 10 are
involved in the present sequence. Note that the terminal device 300A, the base station
200A, the network manager 16A, the network gateway 12A, the terminal device 300B,
the base station 200B, the network manager 16B, and the network gateway 12B form a
different network. In addition, the service platform 11 functions as the communication
control device 100 in the present sequence.
[0084] As shown in FIG. 10, first, the service platform 1 1 checks capability information in
Step S202. For example, the service platform 11 transmits a message requesting c a
pability information to the terminal device 300A, the base station 200A, the terminal
device 300B, and the base station 200B to collect capability information of each of the
devices. Note that the network gateways 12 and the network managers 16 physically
intermediate the exchange of the information.
[0085] Next, in Step S204, the service platform 11 and the application server 10 check
desired communication quality. For example, the service platform 11 inquires the
desired communication quality of the application server 10.
[0086] Next, in Step S206, the service platform 11 checks a state of a communication path.
For example, the service platform 11 inquires the state of the communication path of
the network managers 16A and 16B.
[0087] Next, in Step S208, the service platform 11 decides a communication route.
[0088] Then, in Step S210, the service platform 11 performs allocation of an access setting.
[0089] Next, in Step S212, the service platform 11 performs a resetting of a network. For
example, the service platform 11 notifies each base station 200 and each terminal
device 300 of access setting information indicating the allocation result of Step S210.
[0090] Then, in Step S214, the service platform 11 notifies the application server 10 of
completion of preparation. Accordingly, a service provided by the application server
10 is started, and communication according to the access setting information is started
between the base station 200A and the terminal device 300A and between the base
station 200B and the terminal device 300B.
[0091] Note that, although the example in which the service platform 11 functions as the
communication control device 100 has been described above, the present technology is
not limited thereto. For example, an arbitrary device such as the base station 200 or the
like may function as the communication control device 100. In this case, since the base
station 200 can directly communicate with the terminal device 300, communication
with a device such as the network managers 16, the network gateways 12 can be
skipped when checking capability information or a state of a communication path. In
addition, when the base station 200 or the terminal device 300 can select desired com
munication quality such as when desired quality relating to an application is cat
egorized, the communication control device 100 may omit inquiring about desired
quality to the application server 10.
[0092] <3.2. Transmitting function and receiving function>
Next, more detailed configuration examples of the radio communication device
according to the present embodiment will be described with reference to FIGS. 11 to
14. The configuration described below can be common to a radio communication unit
210 of the base station 200 and a radio communication unit 310 of the terminal device
300. FIGS. 1 1 and 12 illustrate a configuration example of a transmission device
(transmitting function), and FIGS. 13 and 14 illustrate a configuration example of a
reception device (receiving function). These drawings show configuration examples
that can correspond to multiple schemes including Frequency Division Multiplexing
(FDM), Interleave Division Multiple Access (IDMA), Space Division Multiple Access
(SDMA), Superposition Coding (SPC), Rate Splitting Multiple Access (RSMA), and
Sparse Code Multiple Access (SCMA).
[0093] (Transmitting function)
FIGS. 11 and 12 are block diagrams illustrating a functional configuration of the
transmission device according to the present embodiment. As illustrated in FIG. 11, the
transmission device 400 includes a resource mapper 410, a serial-parallel conversion
processing unit 412, FEC encoding processing units 420, interleavers 430, another
serial-parallel conversion processing unit 432, modulation processing units 440, and
spreading processing units 442. In addition, the transmission device 400 further
includes another serial-parallel conversion processing unit 450, SPC processing units
452, another serial-parallel conversion processing unit 460, rate division processing
units 462, an SDM processing unit 470, and FDM processing units 480 as illustrated in
FIG. 12.
[0094] The resource mapper 410 as a function of performing resource mapping targeting n
user signals. The serial-parallel conversion processing units 412, 432, 450, and 460
output input information to a proper succeeding entity, functioning as arbiters
(information arbiters). The FEC encoding processing units 420 have a function of
performing error-correction encoding (for example, forward error correction). The in
terleavers 430 have a function of performing multiplexing using IDMA by interleaving
an input series. The modulation processing units 440 have a function of performing
digital modulation. The spreading processing units 442 have a function of performing
symbol spreading. The modulation processing units 440 and the spreading processing
units 442 perform multiplexing using SCMA. The SPC processing units 452 have a
function of performing multiplexing using SPC. The rate division processing unit 462
has a function of performing multiplexing using RSMA. The SDM processing unit 470
has a function of performing multiplexing using SDMA. The FDM processing units
480 have a function of performing multiplexing using FDM.
[0095] In addition, the transmission device 400 further includes a control entity 405 for con
trolling each of the entities described above as illustrated in FIGS. 11 and 12. The
control entity 405 turns on or off transmitting functions corresponding to each of the
multiplexing schemes by turning on or off operations of each entity, or controls p a
rameters of each entity. The control entity 405 has interfaces I_tx0 to I_tx9 for con
trolling the transmitting functions and parameters corresponding to each of the mul
tiplexing schemes. This is because a proper multiplexing scheme or parameter can be
different in, for example, downlink, uplink, and device-to-device (D2D) commu
nication of a cellular system.
[0096] For example, the control entity 405 multiplexes user data with the same resource
block via the interface I_tx0. The control entity 405 allocates an interleave pattern for
IDMA via the interface I_txl. The control entity 405 selects a pair of signals to be
multiplexed using SCMA via the interface I_tx2. The control entity 405 controls an
encoding process and a digital modulation process for SCMA via the interface I_tx3.
The control entity 405 selects a pair of signals to be multiplexed using SPC via the
interface I_tx4. The control entity 405 controls an SPC process via the interface I_tx5.
The control entity 405 selects a pair of signals to be multiplexed using RSMA via the
interface I_tx6. The control entity 405 controls a rate division process via the interface
I_tx7. The control entity 405 controls an SDM process via the interface I_tx8. The
control entity 405 controls an FDM process via the interface I_tx9.
[0097] (Receiving function)
FIGS. 13 and 14 are block diagrams illustrating a functional configuration of the
transmission device according to the present embodiment. As illustrated in FIG. 13, the
reception device 500 includes FDM demodulation processing units 510, a spatial
equalization processing unit 520, rate division demodulation processing units 530, a
serial-parallel conversion processing unit 532, SIC processing units 540, and another
serial-parallel conversion processing unit 542. In addition, as illustrated in FIG. 14, the
reception device 500 further includes despreading processing units 550, demodulation
processing units 552, another serial-parallel conversion processing unit 560, deinterleavers
562, FEC decoding processing units 570, a feedback loop processing unit
580, and a resource mapper 582.
[0098] The FDM demodulation processing units 510 have a function of demodulating a
signal multiplexed using FDM. The spatial equalization processing unit 520 has a
function of demodulating a signal multiplexed using SDMA. The rate division de
modulation processing units 530 have a function of demodulating a signal multiplexed
using RSMA. The serial-parallel conversion processing units 532, 542, and 560 output
input information to a proper succeeding entity, functioning as arbiters. The SIC
processing units 540 have a function of demodulating a signal multiplexed using SPC.
The despreading processing units 550 have a function of performing despreading of a
signal that has undergone symbol spreading. The demodulation processing units 552
have a function of demodulating a signal that has digitally modulated. The despreading
processing units 550 and demodulation processing units 552 perform demodulation of
a signal multiplexed using SCMA. The deinterleavers 562 have a function of de
modulating a signal multiplexed using IDMA. The FEC decoding processing units 570
have a function of decoding a signal that has undergone error-correction encoding. The
feedback loop processing unit 580 has a function of repeatedly executing the process
from the spatial equalization processing unit 520 to the FEC decoding processing units
570. The resource mapper 582 has a function of acquiring and outputting n user signals
from input signals.
[0099] In addition, the reception device 500 further includes a control entity 505 for con
trolling each of the entities described above as illustrated in FIGS. 13 and 14. The
control entity 505 turns on or off receiving functions corresponding to each of the mul
tiplexing schemes by turning on or off operations of each entity, or controls parameters
of each entity. The control entity 505 has interfaces I_rx0 to I_rx9 for controlling the
transmitting functions and parameters corresponding to each of the multiplexing
schemes.
[0100] For example, the control entity 505 separates user data multiplexed with the same
resource block via the interface I_rx0. The control entity 505 allocates a deinterleave
pattern for IDMA via the interface I_rxl. The control entity 505 separates a pair of
signals multiplexed using SCMA via the interface I_rx2. The control entity 505
controls a despreading process and a demodulation process via the interface I_rx3. The
control entity 505 separates a pair of signals multiplexed using SPC via the interface
I_rx4. The control entity 505 controls an SIC process via the interface I_rx5. The
control entity 505 separates a pair of signals multiplexed using RSMA via the interface
I_rx6. The control entity 505 controls a rate division demodulation process via the
interface I_rx7. The control entity 505 controls a spatial equalization process via the
interface I_rx8. The control entity 505 controls an FDM demodulation process via the
interface I_rx9.
[0101] <3.3. Details of an allocation process of an access setting>
Details of the allocation process of an access setting executed in the communication
system 1 according to the present embodiment will be described below. In the present
specification, details of the process with respect to the communication control device
100, the base station 200, and the terminal device 300 will be described focusing on
access schemes among access settings.
[0102] <3.3.1. Regarding the communication control device>
FIG. 15 is a flowchart showing an example of the flow of an allocation process of an
access setting executed by the communication control device 100 according to the
present embodiment. In the present flowchart, a case in which there is a possibility of
the communication system 1 executing or providing the functions of FDM, SDMA,
SPC, IDMA, RSMA, and SCMA is shown as an example.
[0103] Steps S302 and S304 are processes for determining whether to allocate (i.e., employ)
FDM. Steps S306 to S318 are processes for determining whether to allocate SDMA.
Steps S310 and S312 are processes for determining whether to allocate SPC. Steps
S314 and S316 are processes for determining whether to allocate IDMA. Steps S318
and S320 are processes for determining whether to allocate RSMA. Steps S322 and
S324 are processes for determining whether to allocate SCMA. The order of these de
termination processes is arbitrary. However, since there is a restriction on com
patibility of FDM with existing schemes and a restriction on spatial resources of
SDMA, it is desirable to determine allocation of the schemes earlier than others.
[0104] First, the process of determining whether to allocate FDM is performed as shown in
FIG. 15. Specifically, in Step S302, the control unit 130 determines whether or not it is
necessary to simultaneously execute communication with a legacy RAT using or
thogonal resources. That is, the control unit 130 determines the necessity of com
patibility with the legacy RAT. The legacy RAT is set to indicate, for example,
OFDMA or SC-FDMA that is the existing 4G RAT. The control unit 130 may refer to
capability information of each device for the determination. When communication is
performed including the terminal device 300 which is only compatible with the legacy
RAT, for example, the control unit 130 determines that it is necessary to simul
taneously execute communication with the legacy RAT (Yes in S302). In this case,
FDM is not employed. In other words, the control unit 130 performs allocation to
employ the legacy RAT. On the other hand, when communication is performed
without including the terminal device 300 which is only compatible the legacy RAT,
for example, the control unit 130 determines that it is not necessary to simultaneously
execute communication with the legacy RAT (No in S302). In this case, the control
unit 130 performs a process of determining employment of FDM in Step S304.
[0105] Next, the process of determining whether to allocate SDMA is performed.
Specifically, in Step S306, the control unit 130 determines whether beam steering is effectively
operated for a network or a terminal. When beam steering is determined to be
effectively operated for a network or a terminal (Yes in S306), the control unit 130
performs a process of determining employment of SDMA in Step S308. On the other
hand, when beam steering is determined not to be effectively operated for a network or
a terminal (No in S306), the control unit 130 determines not to employ SDMA. In
SDMA, signals can be transmitted and received from one transmission device to a
plurality of reception devices using the same frequency and time. In this case, the
transmission device desirably has a plurality of antennas, and transmits a signal to each
of the reception devices from the different antennas or transmit respective signals
combined using a precoding technology from the plurality of antennas. The signal
transmitted as above is in a spatially orthogonal or quasi-orthogonal state, and the
reception devices can separate, demodulate, and decode even a signal that has been
multiplexed with the same frequency and time resources through spatial filtering,
maximum likelihood detection, or a detection scheme equivalent thereto. In addition,
in SDMA, signals can be transmitted and received from a plurality of transmission
devices to one reception device using the same frequency and time. In this case, the
reception device desirably has a plurality of antenna. The plurality of transmission
devices transmits signals sharing at least some of frequency resources and time
resources. In order to determine whether or not beam steering is effectively operated
for a network or terminal, for example, it is desirable for the control unit 130 to
discern, for example, an antenna mounting state of each communication device, and a
radio propagation state between the base station 200 and respective terminal devices
300. The reason that discerning a radio propagation state is desirable is that, for
example, when SDMA is attempted to be executed between two transmission devices
and one reception device and radio propagation states between the different
transmission devices and the reception device are similar to each other (for example,
when the correlation between channel response coefficients or transfer functions is
high), it is difficult even for the reception device having the plurality of antennas to
separate, demodulate, and decode signals transmitted from the plurality of transmission
devices. The multiplexing method using SDMA can also be understood as mul
tiplexing in a space area.
At the time of the determination with regard to SPC, IDMA, RSMA, and SCMA
described above, it is desirable to determine the schemes based on spatial resources
(beam) generated through the employment of SDMA. This is because SPC, IDMA,
RSMA, and SCMA are basically non-orthogonal multiple access scheme-based tech
nologies, and it is not necessary to perform multiplexing with respect to signals or
communication devices that already have been assigned to different beams in the stage
of SDMA using non-orthogonal resources. On the other hand, when there is a signal or
a communication device that are not assigned even with SDMA (for example, there are
a plurality of transmission devices or reception devices which have similar radio
propagation states and a high correlation of channel response coefficients), the control
unit 130 determines execution of multiplexing using non-orthogonal resources.
[0107] Next, the process of determining whether to allocate SPC is performed. Specifically,
in Step S310, the control unit 130 determines whether there are communication
devices having different level differences of path loss in the same transmission beam.
When there are determined to be communication devices having different level dif
ferences of path loss in the same transmission beam (Yes in S310), the control unit 130
performs a process of determining employment of SPC in Step S312. On the other
hand, when there is no communication device having different level differences of path
loss in the same transmission beam (No in S310), the control unit 130 determines not
to employ SPC. SPC is a scheme of multiplexing a plurality of signals in a power
space on the same frequency, time, and space. During multiplexing, it is desirable to
allocate electric power of different levels to the power of respective signals. Ac
cordingly, the reception device can easily use SPC as a detection, demodulation, and
decoding scheme. By employing the determination reference of whether or not there
are communication devices having different level differences of path loss in radio
propagation states, the control unit 130 can take a wide control range of quality of
signals to be multiplexed considering both the level difference of the signals to be mul
tiplexed and the level difference of path loss. The multiplexing method using SPC can
also be understood as multiplexing in an electric power area.
[0108] Next, the process of determining whether to allocate IDMA is performed.
Specifically, in Step S314, the control unit 130 determines whether or not there are still
communication devices which have difficulty multiplexing in the same transmission
beam. When it is determined that there are still communication devices which have
difficulty multiplexing in the same transmission beam (Yes in S314), the control unit
130 performs a process of determining employment of IDMA in Step S316. On the
other hand, when it is determined that there is no communication device having
difficulty multiplexing in the same transmission beam (No in S314), the control unit
130 determines not to employ IDMA. IDMA is also a kind of non-orthogonal multiple
access schemes, and basically uses error-correction codes and iterative (turbo) received
signal processing. While a plurality of different signal and communication devices use
at least some of the same frequency, time, space, and electric power, the transmission
devices uses different interleave patterns of interleave to be applied to respective
signals. Accordingly, the reception device can easily perform signal separation, de
modulation, and decoding. This multiplexing method can also be understood as mul
tiplexing in an interleave area or a bit area. Note that, in IDMA, different interleave
patterns may be applied to communication devices or signals allocated to different
spatial resources.
[0109] Next, the process of determining whether to allocate RSMA is performed.
Specifically, in Step S318, the control unit 130 determines whether or not there are still
communication devices having difficulty multiplexing in the same transmission beam.
When it is determined that there are still communication devices having difficulty mul
tiplexing in the same transmission beam (Yes in Step S318), the control unit 130
performs a process of determining employment of RSMA in Step S320. On the other
hand, when it is determined that there is no communication device having difficulty
multiplexing in the same transmission beam (No in S318), the control unit 130 de
termines not to employ RSMA. Although having a similar aspect to SPC, RSMA is a
non-orthogonal multiple access scheme in which multiplexing is performed while
adjusting a communication rate (coding rate, modulation scheme, or the like) so that
signals of different communication devices can be received while they interfere with
each other. By adjusting a coding rate or modulation scheme, the communication
devices can control tolerance with respect to signal quality (for example, SINR, SNR,
or the like).
[0110] Next, the process of determining whether to allocate SCMA is performed.
Specifically, in Step S322, the control unit 130 determines whether or not there are still
communication devices having difficulty multiplexing in the same transmission beam.
When it is determined that there are still communication devices having difficulty mul
tiplexing in the same transmission beam (Yes in Step S322), the control unit 130
performs a process of determining employment of SCMA in Step S324. On the other
hand, when it is determined that there is no communication device having difficulty
multiplexing in the same transmission beam (No in S322), the control unit 130 de
termines not to employ SCMA. Although being a similar scheme to CDMA, SCMA is
a method in which sparse codes (signatures) including {0, 1} (in which the ratio of 1 is
low) are used instead of spreading codes and multiplexing is performed by allocating
signatures of different patterns to different signals. In addition to employing such
signatures, in terms of a digital modulation scheme, signal processing such as a unitary
transformation of modulation symbols of PSK and QAM, or modulation symbols with
non-uniform inter-signal-point distances on a constellation (non-uniform constellation)
may be applied. The reception device can separate signature-multiplexed signals using
iterative signal processing or turbo signal processing such as a message transmission
method (message passing algorithm).
[01 11] In Steps S304, S308, S312, S316, S320, and S324 described above, allocation or
non-allocation of each multiplexing scheme is specifically determined. A multiplexing
scheme of an omitted step is set not to be allocated. With this structure of the
flowchart, complexity of the determination process can be avoided.
[0112] Details of the processes of determining employment of the various multiplexing
schemes in Steps S304, S308, S3 12, S316, S320, and S324 will be described below.
[0113] (FDM employment determination process)
FIG. 16 is a flowchart showing an example of the flow of the FDM employment de
termination process executed in the communication control device 100 according to
the present embodiment.
[01 14] As shown in FIG. 16, the control unit 130 first determines whether or not it is
necessary to simultaneously execute communication with the legacy RAT using or
thogonal resources in Step S402. This determination is the same as that of Step S302 in
FIG. 15.
[0115] When simultaneously executing communication with the legacy RAT using or
thogonal resources is determined to be necessary (Yes in Step S402), the control unit
130 employs OFDM as a modulation scheme to be allocated in Step S404. Not
employing FDM can be understood as being equivalent to employing OFDM.
[0116] When simultaneously executing communication with the legacy RAT using or
thogonal resources is determined not to be necessary (No in Step S402), the control
unit 130 determines whether or not electric power of a transmission device and
reception device is problematic in Step S406. As a problem of electric power, for
example, a peak-to-average power ratio (PAPR) is exemplified.
[01 17] When electric power is determined to be problematic (Yes in S406), the control unit
130 employs single carrier modulation (for example, SC-FDMA) as a modulation
scheme to be allocated in Step S408.
[0118] On the other hand, when electric power is determined not to be problematic (No in
S406), the control unit 130 employs Filter Bank Multi-Carrier (FBMC) as a
modulation scheme to be allocated in Step S410. Note that the meaning "not being
problematic" includes a trivial problem.
[01 19] As described above, the control unit 130 can employ multiplexing schemes
(modulation schemes) to be allocated through Steps S404, and S408 or S410. The
control unit 130 may end the process with the steps, or adopt the following flow (each
step from Step S412). A different modulation scheme may be employed through the
following flow. In addition, when the same modulation schemes are employed by
executing Steps S404 and S408 or S410 again in the following flow, for example, the
control unit 130 may execute a process of adjusting a parameter to be used in
modulation, in addition to selection of the modulation schemes. In addition, when
Steps S404 and S408 or S410 are executed a predetermined number of times, the
control unit 130 may employ a modulation scheme selected the predetermined number
of times, and end the process. In addition, when the process ends without selecting a
scheme the predetermined number of times, the control unit 130 may determine not to
employ FDM.
[0120] When single carrier modulation is employed, the control unit 130 determines whether
or not an achievable system capacity is sufficient in Step S412. For example, the
control unit 130 estimates a system capacity (a throughput, a user capacity, a user
throughput, or the like) that can be achieved through single carrier modulation, and de
termines whether or not the result of the estimation reaches a target value.
[0121] When the achievable system capacity is determined not to be sufficient (No in S412),
the control unit 130 employs FBMC as a modulation scheme to be allocated in Step
S410. There is a possibility of FBMC having higher frequency use efficiency than
single carrier modulation.
[0122] On the other hand, when the achievable system capacity is determined to be
sufficient (Yes in S412), the control unit 130 determines in Step S414 whether or not
data of a plurality of services and applications can be efficiently handled when single
carrier modulation is employed.
[0123] When it is determined that the data can be efficiently handled (Yes in S414), the
process returns to Step S408 again.
[0124] On the other hand, when it is determined that the data will not efficiently handled
(No in S414), the control unit 130 determines in Step S416 whether or not the data of a
plurality of services and applications can be handled through resource sharing in the
time direction when single carrier modulation is employed.
[0125] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S416), the process returns to Step S408 again.
[0126] On the other hand, when it is determined that the data will not be handled with
resource sharing in the time direction (No in Step S416), the control unit 130 changes
the modulation scheme to be employed to FBMC in Step S410.
[0127] When FBMC is employed, the control unit 130 determines in Step S418 whether or
not complexity of the configuration of the transmission device and/or the reception
device is problematic. This is because FBMC generally involves higher complexity of
a configuration than others.
[0128] When it is determined that complexity is problematic (Yes in S418), the control unit
130 employs OFDM as a modulation scheme to be allocated in Step S404.
[0129] On the other hand, when it is determined that complexity is not problematic (No in
S418), the control unit 130 determines in Step S420 whether or not an achievable
system capacity using FBMC is sufficient.
[0130] When an achievable system capacity is determined to be sufficient (Yes in S420), the
process returns to Step S410 again.
[0131] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S420), the control unit 130 determines in Step S422 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when FBMC is employed.
[0132] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S422), the process returns to Step S410 again.
[0133] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S422), the process ends.
[0134] When OFDM is employed, the control unit 130 determines in Step S424 whether or
not an achievable system capacity using OFDM is sufficient.
[0135] When an achievable system capacity is determined to be sufficient (Yes in S424), the
process returns to Step S404 again.
[0136] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S424), the control unit 130 determines in Step S426 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when OFDM is employed.
[0137] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S426), the process returns to Step S404 again.
[0138] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S426), the control unit 130 ends the
process.
[0139] (SDMA employment determination process)
FIG. 17 is a flowchart showing an example of the flow of the SDMA employment
determination process executed in the communication control device 100 according to
the present embodiment. In FIG. 17, the flowchart for examining whether to employ
SDMA that uses a two-dimensional (2D) space or to employ SDMA that uses a threedimensional
(3D) space is shown. Note that Steps S502 to S510 are a process of de
termining whether or not SDMA that uses a 2D space is to be employed. In addition,
Steps S512 to S520 are a process of determining whether or not SDMA that uses a 3D
space is to be employed. Either of the determination processes may be omitted.
[0140] As shown in FIG. 17, the control unit 130 first determines in Step S502 whether or
not complexity of the configuration of the transmission device is problematic when
SDMA using a 2D space is employed.
[0141] When complexity is determined to be problematic (Yes in S502), the control unit 130
determines not to employ SDMA and the process ends.
[0142] On the other hand, when complexity is determined not to be problematic (No in
S502), the control unit 130 determines in Step S504 whether or not overhead of the
system is problematic when SDMA using the 2D space is employed.
[0143] When overhead is determined to be problematic (Yes in S504), the control unit 130
determines not to employ SDMA and the process ends.
[0144] On the other hand, when overhead is determined not to be problematic (No in S504),
the control unit 130 determines to employ SDMA using the 2D space as a multiplexing
scheme to be allocated.
[0145] Next, in Step S508, the control unit 130 determines an achievable system capacity is
sufficient when SDMA using the 2D space is employed.
[0146] When an achievable system capacity is determined to be sufficient (Yes in S508), the
process returns to Step S516 again.
[0147] When an achievable system capacity is determined not to be sufficient (No in S508),
the control unit 130 determines in Step S510 whether or not data of a plurality of
services and applications can be handled through resource sharing in the time direction
when SDMA using a 2D space is employed.
[0148] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S510), the process returns to Step S506 again.
[0149] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S510), the control unit 130 determines in
Step S512 whether or not complexity of the configuration of the transmission device is
problematic when SDMA using a 3D space is employed.
[0150] When complexity is determined to be problematic (Yes in S512), the process ends.
[0151] On the other hand, when complexity is determined not to be problematic (No in
S512), the control unit 130 determines in Step S514 whether or not overhead of the
system is problematic when SDMA using the 3D space is employed.
[0152] When overhead is determined to be problematic (Yes in S514), the process ends.
[0153] On the other hand, when overhead is determined not to be problematic (No in S514),
the control unit 130 determines in Step S516 to employ SDMA using the 3D space as a
multiplexing scheme to be allocated.
[0154] Next, in Step S518, the control unit 130 determines an achievable system capacity is
sufficient when SDMA using the 3D space is employed.
[0155] When an achievable system capacity is determined to be sufficient (Yes in S518), the
process returns to Step S506 again.
[0156] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S518), the control unit 130 determines in Step S510 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when SDMA using a 3D space is employed.
[0157] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S520), the process returns to Step S516 again.
[0158] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S520), the process ends.
[0159] As described above, the control unit 130 can employ a multiplexing scheme to be
allocated through Step S506 or S516. As the description above with respect to FIG. 16,
when Step S506 or S516 is executed again and the same multiplexing scheme is
employed, for example, the control unit 130 may execute a process of adjusting a
parameter to be used for SDMA in addition to selection of 2D or 3D. In addition, when
Step S506 or S516 is executed a predetermined number of times, the control unit 130
may employ a multiplexing scheme selected the predetermined number of times and
end the process. In addition, when the process ends without the selection of the prede
termined number of times, the control unit 130 may determine not to employ SDMA.
[0160] (SPC employment determination process)
FIG. 18 is a flowchart showing an example of the flow of the SPC employment de
termination process executed in the communication control device 100 according to
the present embodiment.
[0161] As shown in FIG. 18, the control unit 130 first determines in Step S602 whether or
not a processing load of the transmission device and reception device is problematic
when SPC is employed. The control unit 130 may determine whether or not
complexity of the configuration of the transmission device and reception device is
problematic, instead of or in parallel with a processing load.
[0162] When the processing load is determined to be problematic (Yes in S602), the control
unit 130 determines not to employ SPC and the process ends.
[0163] On the other hand, when a processing load is determined not to be problematic (No
in S602), the control unit 130 determines in Step S604 whether or not a delay in
decoding of the reception device is problematic when SPC is employed. This is
because, since it is desirable for the reception device side in a non-orthogonal mul
tiplexing scheme such as SPC to overcome interference, which is caused by mul
tiplexing performed using non-orthogonal resources, even through signal processing,
there is a possibility of a longer delay than in an orthogonal multiplexing scheme
occurring.
[0164] When the delay in decoding is determined to be problematic (Yes in S604), the
control unit 130 determines not to employ SPC and the process ends.
[0165] On the other hand, when the delay in decoding is determined not to be problematic
(No in S604), the control unit 130 determines in Step S606 whether or not electric
power of the reception device is problematic. For example, the control unit 130 de
termines whether or not consumption power of the reception device is problematic.
[0166] When electric power is determined to be problematic (Yes in S606), the control unit
130 determines not to employ SPC and the process ends.
[0167] On the other hand, when electric power is determined not to be problematic (No in
S606), the control unit 130 employs SPC as a multiplexing scheme to be allocated in
Step S608.
[0168] Next, in Step S610, the control unit 130 determines an achievable system capacity is
sufficient when SPC is employed.
[0169] When an achievable system capacity is determined to be sufficient (Yes in S610), the
process returns to Step S608 again.
[0170] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S610), the control unit 130 determines in Step S612 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when SPC is employed.
[0171] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S612), the process returns to Step S608 again.
[0172] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S612), the process ends.
[0173] As described above, the control unit 130 can employ a multiplexing scheme to be
allocated through Step S608. When Step S608 is executed again as described above
with respect to FIG. 16, for example, the control unit 130 may execute a process of
adjusting a parameter to be used for SPC. In addition, when Step S608 is executed a
predetermined number of times, the control unit 130 may employ SPC and end the
process. In addition, when the process ends without selection of the predetermined
number of times, the control unit 130 may determine not to employ SPC.
[0174] (IDMA employment determination process)
FIG. 19 is a flowchart showing an example of the flow of the IDMA employment de
termination process executed in the communication control device 100 according to
the present embodiment.
[0175] The control unit 130 first determines in Step S702 whether or not complexity of the
configurations of the transmission device and the reception device is problematic when
IDMA is employed.
[0176] When complexity is determined to be problematic (Yes in S702), the control unit 130
determines not to employ IDMA and the process ends.
[0177] On the other hand, when complexity is determined not to be problematic (No in
S702), the control unit 130 determines in Step S704 whether or not an achievable peak
rate or peak throughput is problematic when IDMA is employed.
[0178] When an achievable peak rate or peak throughput is determined to be problematic
(Yes in S704), the control unit 130 determines not to employ IDMA and ends the
process.
[0179] On the other hand, when an achievable peak rate or peak throughput is determined
not to be problematic (No in S704), the control unit 130 determines in Step S706
whether or not simultaneous communication with the legacy RAT that is not
compatible with IDMA is problematic when IDMA is employed. Since adjustment of
the level of electric power is generally not performed in IDMA as in SPC, interference
caused by multiplexing of IDMA can be severer than in SPC. For this reason, there is a
possibility of simultaneous multiplexing with a legacy device being difficult. Thus,
when it is necessary to simultaneously communicate with a legacy device, it is
desirable to avoid employing IDMA.
[0180] When simultaneous communication with the legacy RAT that is not compatible with
IDMA is determined to be problematic (Yes in S706), the control unit 130 determines
not to employ IDMA and the process ends.
[0181] On the other hand, when simultaneous communication with the legacy RAT that is
not compatible with IDMA is determined not to be problematic (No in S706), the
control unit 130 employs IDMA as a multiplexing scheme to be allocated in Step
S708.
[0182] Next, in Step S710, the control unit 130 determines an achievable system capacity is
sufficient when IDMA is employed.
[0183] When an achievable system capacity is determined to be sufficient (Yes in S710), the
process returns to Step S708 again.
[0184] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S710), the control unit 130 determines in Step S712 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when IDMA is employed.
[0185] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S712), the process returns to Step S708 again.
[0186] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S712), the process ends.
[0187] As described above, the control unit 130 can employ a multiplexing scheme to be
allocated through Step S708. When Step S708 is executed again as described above
with respect to FIG. 16, for example, the control unit 130 may execute a process of
adjusting a parameter to be used for IDMA. In addition, when Step S708 is executed a
predetermined number of times, the control unit 130 may employ IDMA and end the
process. In addition, when the process ends without selection of the predetermined
number of times, the control unit 130 may determine not to employ IDMA.
[0188] (RSMA employment determination process)
FIG. 20 is a flowchart showing an example of the flow of the RSMA employment
determination process executed in the communication control device 100 according to
the present embodiment.
[0189] As shown in FIG. 20, the control unit 130 first determines in Step S802 whether or
not complexity of the configuration of the transmission device is problematic.
[0190] When complexity is determined to be problematic (Yes in S802), the control unit 130
determines not to employ RSMA and the process ends.
[0191] On the other hand, when complexity is determined not to be problematic (No in
S802), the control unit 130 determines in Step S804 whether or not electric power of
the transmission device is problematic when RSMA is employed.
[0192] When electric power is determined to be problematic (Yes in S804), the control unit
130 determines not to employ RSMA and the process ends.
[0193] On the other hand, when electric power is determined not to be problematic (No in
S804), the control unit 130 employs RSMA as a multiplexing scheme to be allocated in
Step S806.
[0194] Next, in Step S808, the control unit 130 determines an achievable system capacity is
sufficient when RSMA is employed.
[0195] When an achievable system capacity is determined to be sufficient (Yes in S808), the
process returns to Step S806 again.
[0196] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S808), the control unit 130 determines in Step S810 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when RSMA is employed.
[0197] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S810), the process returns to Step S806 again.
[0198] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S810), the process ends.
[0199] As described above, the control unit 130 can employ a multiplexing scheme to be
allocated through Step S806. When Step S806 is executed again as described above
with respect to FIG. 16, for example, the control unit 130 may execute a process of
adjusting a parameter to be used for RSMA. In addition, when Step S806 is executed a
predetermined number of times, the control unit 130 may employ RSMA and end the
process. In addition, when the process ends without selection of the predetermined
number of times, the control unit 130 may determine not to employ RSMA.
[0200] (SCMA employment determination process)
FIG. 2 1 is a flowchart showing an example of the flow of the SCMA employment
determination process executed in the communication control device 100 according to
the present embodiment.
[0201] First, in Step S902, the control unit 130 determines whether or not the electric power
of the reception device is problematic when SCMA is employed.
[0202] When electric power is determined to be problematic (Yes in S902), the control unit
130 determines not to employ SCMA and the process ends.
[0203] On the other hand, when electric power is determined not to be problematic (No in
S902), the control unit 130 determines in Step S904 whether or not simultaneous com
munication with the legacy RAT that is not compatible with SCMA is problematic.
[0204] When simultaneous communication with the legacy RAT that is not compatible with
IDMA is determined to be problematic (Yes in S904), the control unit 130 determines
not to employ SCMA and the process ends.
[0205] On the other hand, when simultaneous communication with the legacy RAT that is
not compatible with SCMA is determined not to be problematic (No in S904), the
control unit 130 determines in Step S906 whether or not a delay in decoding of the
reception device is problematic.
[0206] When the delay in decoding is determined to be problematic (Yes in S906), the
control unit 130 determines not to employ SCMA and the process ends.
[0207] On the other hand, when a delay in decoding is determined not to be problematic (No
in S906), the control unit 130 employs SCMA as a multiplexing scheme to be allocated
in Step S908. The control unit 130 may select a digital modulation scheme to be
employed in addition to the employment of SCMA. For example, the control unit 130
may determine whether to employ a modulation scheme that has employed non
uniform signal point disposition (Non-Uniform Constellation) or Unbalance
Modulation (UBM) for QPSK, 16QAM, 64QAM, 256QAM, and the like. For
example, the control unit 130 may employ NUC when SCMA is employed, or employ
Uniform Constellation (UC) when SCMA s not employed.
[0208] Next, in Step S910, the control unit 130 determines an achievable system capacity is
sufficient when SCMA is employed.
[0209] When an achievable system capacity is determined to be sufficient (Yes in S910), the
process returns to Step S908 again.
[0210] On the other hand, when an achievable system capacity is determined not to be
sufficient (No in S910), the control unit 130 determines in Step S912 whether or not
data of a plurality of services and applications can be handled through resource sharing
in the time direction when SCMA is employed.
[021 1] When it is determined that the data can be handled with resource sharing in the time
direction (Yes in Step S912), the process returns to Step S908 again.
[0212] On the other hand, when it is determined that the data will not be handled through
resource sharing in the time direction (No in S912), the process ends.
[0213] As described above, the control unit 130 can employ a multiplexing scheme to be
allocated through Step S908. When Step S908 is executed again as described above
with respect to FIG. 16, for example, the control unit 130 may execute a process of
adjusting a parameter to be used for SCMA. In addition, when Step S908 is executed a
predetermined number of times, the control unit 130 may employ SCMA and end the
process. In addition, when the process ends without selection of the predetermined
number of times, the control unit 130 may determine not to employ SCMA.
[0214] <3.3.2. Regarding a base station and a terminal device>
(Signal processing on a transmission device side)
Signal processing on a transmission device side according to an access setting
allocated by the communication control device 100 will be described below. Herein
processing when IDMA, SPC, SCMA, SDMA (or SDM), and OFDMA (or SCFDMA)
are allocated will be described as an example. Note that, when there is an
access scheme not allocated by the communication control device 100, processing
relating to an access scheme not allocated in the processing described below may be
skipped. The expression of a vector included in the following description is set to
indicate a column vector unless specified otherwise. In addition, description will be
provided focusing on signals of a user k unless particularly specified.
[0215] In addition, the base station 200 will be described below as a station functioning as a
transmission device on the assumption of downlink communication. In uplink, the
terminal device 300 functions as a transmission device, and thus performs the same
process as described below.
[0216] (A) Decision of a data size
First, the control unit 240 decides the data size of data that the user k transmits. The
body of the data size is equivalent to a packet data size, a frame data size or a transport
block size (TBS). This size is desirably decided based on the amount of orthogonal and
non-orthogonal resources allocated to the user k, a modulation scheme, a coding rate,
or the like. A data size NB t ,TBs,k computed using, for example, the following Ex
pression 1.
[0217] [Math.l]
B BS
Expression 1
Here, Ik indicates an interleaver index group allocated to the user k. Pk indicates an
SPC/electric power level layer index group allocated to the user k. Ck indicates a code
resource index group of SCMA allocated to the user k. Sk indicates a spatial resource
index group allocated to the user k. Rk indicates a resource block index group allocated
to the user k. N indicates the number of resource elements per interleaver i,
electric power layer p, code c, space s, and resource block r. Q i indicates bit e f
ficiency per resource element (roughly, multiplication of the number of bits and a code
rate per modulation symbol). In addition, floor(x) in Expression 1 is a function for
computing a maximum integer that is equal to or lower than a value x.
[0219] As another example, the same modulation scheme and coding rate can also be used
between allocated resources. With this setting, an amount of access setting information
can be reduced. In such a case, a data size is calculated using the following Expression
2.
[0220] [Math.2]
Bs j =
Expression 2
[0221] Further, a data size candidate table may be shared between communication devices.
In such a case, notification of a data size between transmission and reception devices is
further simplified, and thus low overhead is achieved. In that case, the final data size is
calculated using the following Expression 3.
[0222] [Math.3]
Expression 3
[0223] Here, cand indicates the number of data size candidates. NB t ,TBs,cand,m indicates an m-th
data size candidate.
[0224] Note that, when the data size candidate table is not shared, the final data size may be
calculated using the following Expression 4.
[Math.4]
=N
Expression 4
[0225] Note that the processes described above can be performed by the resource mapper
410 and the serial-parallel conversion processing unit 412 shown in FIG. 11.
[0226] (B) Error correction code
The control unit 240 controls the radio communication unit 210 to perform error
correction using an error correction encoder. A vector including a transmission bit b k
(n = 0, .. ., NB it,TBs,k- l ) is set to bk. The radio communication unit 210 may encode the
transmission series in a mass or in units of radio resources. Note that the configuration
example illustrated in FIG. 11 corresponds to the latter configuration.
[0227] A coded bit vector b'k including coding bit b' k (m = 0, .. ., NC o dedBit ,k-l) when the
series is coded in a mass is expressed with the following Expression 5.
[0228] [Math.5]
b' = FEC(bk,M,k)
Expression 5
[0229] Here, FEC(x) is a function indicating coding, and M indicates a coding rate. As
shown in Expression 5 above, error correction coding depends on the user k or may be
variable.
[0230] As another example, coding per succeeding interleaver is considered. First, it is
desirable to sort transmission bits to interleaver resources. For this sorting, for
example, a parser, serial-to-parallel conversion, or the like can be used. As an example
of a sorting rule to an i-th interleaver, the following Expression 6 is considered.
[0231] [Math.6]
i' n o Nj ,
= floor n/N k),
Expression 6
[0232] Here, i' = 0, .. ., N k-1. N k indicates the number of interleavers allocated to the user
k.
[0233] Attention should be paid to the index i of interleavers for the entire radio commu
nication unit 210 and the index i' for the number of interleavers of the user k because
they have different meanings. Attention should also be paid to the relation of indexes
of other resources below.
[0234] When NB t,TBs,k a number that is indivisible by N k, the radio communication unit
210 may embed a dummy bit, a padding bit, a filler bit, or the like for numbercrunching.
For example, the radio communication unit 210 may set b k as a dummy
bit for n' = NB t,TBs,k k-1 of i' = (NB t,TBs,k mod N k), ..., N k-1. The radio commu
nication unit 210 executes error correction coding for each sorted transmission bit after
the sorting. The vector of a coded bit b' k (m = 0, .. ., NCod dB 'k-l) expressed with,
for example, the following Expression 7.
[0235]
[Math.7]
Expression 7
[0236] As shown in Expression 7 above, a coded rate may be a variable coded rate M
according to i.
[0237] Note that the above processes can be performed by the FEC encoding processing
units 420 shown in FIG. 11.
[0238] (C) Interleave
The radio communication unit 210 interleaves the coded rate after the error
correction coding. As shown in Expression 5 above, when error correction coding is
performed in a mass, the radio communication unit 210 sorts coded bits to each in
terleaver. As an example of a sorting rule to an i'-th interleaver, the following Ex
pression 8 is considered.
[0239] [Math. 8]
i' =n Nj
floor(n/N )
n'= , , NcodedBU-k
- 1 N
Expression 8
[0240] When NCodedBit,k is a number that is indivisible by N k , the radio communication unit
210 may embed a dummy bit, a padding bit, a filler bit, or the like for numbercrunching.
For example, the radio communication unit 210 may set b' ,i',k as a dummy
bit for n' = NC odedB t,k N k -l of i' = (NC odedBit,k mod N k), .. . , N k -1. In addition, the radio
communication unit 210 may further insert a dummy bit, considering a digital
modulation scheme of the later stage. For example, when NcodedBit, r,k is not an integral
multiple of the number of bits MB per symbol of a modulation scheme of the later
stage, the radio communication unit 210 may insert a dummy bit into the shortfall so
that it becomes an integral multiple.
[0241] Then, the radio communication unit 210 executes interleave with respect to each
coded bit series. When an interleave pattern of an interleaver i allocated to the user k is
set to P ( ) and an i'-th series of the user k is set to correspond to the interleaver i, the
vector b" k of the bit series after the interleave is expressed with the following Expression
9.
[0242] [Math.9]
Expression 9
[0243] Note that the length of the bit series after the interleave may be the same as that
before the interleave.
[0244] Note that the processes described above can be performed by the interleaver 430 and
the serial-parallel conversion processing unit 432 shown in FIG. 11.
[0245] (D) Digital modulation
The radio communication unit 210 maps the bit series to a modulation symbol that is
a complex number after interleave. The bit series is mapped to a complex symbol for
each MB according to a modulation scheme. Here, MB is the number of bits per
complex symbol. For example, MB = 2 in QPSK, MB = 4 in 16QAM, and MB — in
64QAM. The type of modulation scheme used by the radio communication unit 210 is
controlled by the control unit 240. Note that, when the terminal device 300 is a
transmission device, it can be controlled by the base station 200.
[0246] When a modulation scheme of UC is used, a vector s k of a complex symbol s k
after modulation (m = 0, .. ., Ns b oi,r,k-l) expressed with the following Expression 10.
[0247] [Math. 10]
r = c ( 'rjt > B/ )
Expression 10
[0248] On the other hand, when a modulation scheme of NUC is used, the vector s of the
complex symbol after modulation is expressed with the following Expression 11.
[0249] [Math. 11]
* j = aPP r c (b t )
Expression 1 1
[0250] A modulation scheme (the value of MB and whether UC or NUC is used) may be
variable or different with respect to the index i. In addition, average electric power of
the complex symbol after modulation is set to be normalized to 1.
[0251] Note that the processes described above can be performed by the modulation
processing units 440 shown in FIG. 11.
[0252] (E) Symbol spreading
The radio communication unit 210 executes a spreading process after mapping to a
complex symbol. A spreading code series c (spreading rate SFC) is set to be allocated to
the interleaver resource index i. When the series is set to xc l (1 = 0, .. ., SFC-1), a
complex symbol series s' k of a symbol S k (G = 0, NSymbo kSFc-l) is expressed
with the following Expression 12.
[0253] [Math. 12]
Expression 12
[0254] In addition, this spreading process is expressed by vectors with the following Expression
13.
[0255] [Math. 13]
l ... xl
Fxl F l =
xl F
0 ...
l
Expression 13
[0256] Here, 0 SF I means a zero vector of a length SF.
[0257] If spreading is skipped, the radio communication unit 210 may set SFC= 1 and xC 0=l.
The spreading series used here may take an arbitrary value; however, it is desirable to
meet three conditions that zero may be included, the absolute value is 1 when it is not a
zero, and the value is + 1 or - 1 when it is an integer.
[0258] Note that the process described above can be performed by the spreading processing
units 442 shown in FIG. 11.
[0259] (F) Multiplexing and allocation of electric power using SPC
The radio communication unit 210 executes multiplexing using SPC after spreading.
With the processes described above, N k complex series are generated. The radio com
munication unit 210 sorts this complex series to the number of power resource indexes
Npk allocated to the user k again. As a rule of this sorting, for example the following
Expression 14 is considered.
[0260]
[Math. 14]
S o',p',k ~ l',i'Jc '
o' = floor{(l'NI k + i')/N } ,
'= (l'NI J +i') N ,
p'= , ,N k -
Expression 14
[0261] After the sorting, the radio communication unit 210 sorts an electric power level Ap
corresponding to the p'-th electric power resources to each series s"P k . In this case,
each series is expressed as the following expression.
[0262] [Math. 15]
Expression 15
[0263] Here, the value of the allocated electric power level Ap is desirably different due to p.
After electric power is allocated, the radio communication unit 210 may perform mul
tiplexing (addition) using SPC with respect to a signal of the same user k. In this case,
the complex vector vk after multiplexing is expressed with the following expression.
[0264] [Math. 16]
v *= å
p'=0
Expression 16
[0265] Note that the processes described above can be performed by the serial-parallel
conversion processing unit 450 and the SPC processing units 452 shown in FIG. 12.
[0266] (G) SDMA
The radio communication unit 210 executes multiplexing in the orthogonal frequency
and space directions for OFDMA and SDMA after multiplexing and allocation of
electric power are executed using SPC. As a mechanism of the radio communication
unit 210 for assigning a complex symbol in the frequency and space directions, a
method of assigning a complex symbol in the order of the frequency direction as the
first and the space direction as the second, and a method of assigning a complex
symbol in the order of the space direction as the first and the frequency direction as the
second are considered.
[0267] In the method of assigning a complex symbol in the order of the frequency direction
as the first and the space direction as the second, the radio communication unit 210
assigns a complex symbol in the frequency direction first. When N k resource blocks
are assigned to the user k, the complex symbol u r kof the r'-th resource block is
expressed with the following expression.
[0268] [Math. 17]
ug . ,r',k = V.o'Jc'
q = floor (o'/NRk) ,
r ' =o'modNR
Expression 17
[0269] Next, the radio communication unit 210 further sorts the series assigned to each
resource block in the space direction. The sorted series u' W k is expressed with the
following expression.
[0270] [Math. 18]
U q',s',r',k ~ U q,r',k »
q' = floor (q/N S k) ,
s' = qmod Ns k
Expression 18
[0271] On the other hand, in the method of assigning a complex symbol in the order of the
space direction as the first and the frequency direction as the second, the radio commu
nication unit 210 assigns an SPC multiplexed signal in the space direction first. When
Ns k resource blocks are assigned to the user k, the complex symbol u k of the s'-th
space resources is expressed with the following expression.
[0272] [Math. 19]
q,s'Jc = o'J
q = floor (o'/NSk),
s' = o' dNS J
Expression 19
[0273] Next, the radio communication unit 210 further sorts the series assigned to each
space resource in the space direction. The sorted series u' k is expressed with the
following expression.
[0274] [Math.20]
q',s',r',k q,s',k
q' = floor {q/N R ) ,
r ' = q dNRk
Expression 20
[0275] The mechanism of the radio communication unit 210 for assigning a complex symbol
in the frequency and space directions has been described above.
[0276] Further, the radio communication unit 210 assigns a series u' k to a subcarrier f for
each resource block.
[0277] [Math.21]
q = floor (q'/N
f ' = q' dNF
Expression 2 1
[0278] Here, N k is the number of subcarriers per resource block.
[0279] Then, the radio communication unit 210 executes precoding for SDMA with respect
to the complex symbol allocated to the space resources. The space symbol vector y
q ,r f,k after precoding is expressed with the following expression.
[0280] [Math.22]
Expression 22
[028 1] Wr k represents a precoder matrix allocated to the user k. The size of Wr f k is NTX N
s>k, and NTX represents the number of transmission antennas. u" r k represents the
vector of a precoded symbol u" W f k (s' = 0, .. ., Ns>k-1).
[0282] The radio communication unit 210 may multiplex (add) symbols of users to be si
multaneously transmitted and received after precoding. In this case, if the number of
users to be multiplexed is set to K, a signal after the multiplexing is expressed with the
following expression.
[0283]
[Math.23]
K-
*=0
Expression 23
[0284] If the radio communication unit 210 does not perform multiplexing expressed in the
Expression 23, it is desirable that transmission signals be assigned to different antenna
ports with respect to the user index k.
[0285] Note that the processes described above can be performed by the SDM processing
unit 470 shown in FIG. 12.
[0286] (H) Reference signal
The radio communication unit 210 stores reference signals (RSs) in transmission
signals. An RS is used in channel estimation or the like on a reception device side. It is
desirable to dispose RSs in a predetermined subcarrier within a band, and a prede
termined symbol within a subframe when OFDMA is employed.
[0287] (I) OFDMA
The radio communication unit 210 executes an inverse discrete Fourier transform
(IDFT) or an inverse fast Fourier transform (IFFT) for OFDMA. After the transform,
the radio communication unit 210 transmits signals from each antenna, by adding
cyclic prefixes (CPs) or guard intervals (GIs) thereto, if necessary.
[0288] Note that the processes described above can be performed by the FDM processing
units 480 shown in FIG. 12.
[0289] (Signal processing on a reception device side)
Signal processing on a reception device side according to an access setting allocated
by the communication control device 100 will be described below. Herein processing
when IDMA, SPC, SCMA, SDMA (or SDM), and OFDMA (or SC-FDMA) are
allocated will be described as an example. Note that, when there is an access scheme
not allocated by the communication control device 100, processing relating to an
access scheme not allocated in the processing described below may be skipped. The
expression of a vector included in the following description is set to indicate a column
vector unless specified otherwise. An objective of a reception device is to decode a bit
series bk transmitted to itself.
[0290] In addition, description will be provided on the assumption that the terminal device
300 functions as a reception device in downlink communication below. In uplink, the
base station 200 functions as a reception device, and the processes to be described
below are performed in the same manner.
[0291] (A) Reception symbol
A reception symbol is transmitted from a transmission antenna at the end of a
transmission process of a transmission device described above, passes through a radio
propagation path, and then reaches the terminal device 300 functioning as a reception
device. Hereinbelow, a reception symbol is also set to be expressed in the form of a
vector.
[0292] When the transmission device employs OFDMA, the radio communication unit 310
deletes CPs or GIs from signals received from reception antennas, and obtains symbols
of each subcarrier of a frequency area by executing a FFT or a DFT. A reception
symbol after the transform in the frequency area is expressed with vectors of the
following expression.
[0293] [Math.24]
Expression 24
[0294] H represents a channel response matrix of the transmission device and the
terminal device 300. A channel response here means a response for each subcarrier.
The size of H W is N X NTX, and N X represents the number of reception antennas of
the radio communication unit 310. n r f is a vector including noise and other cell in
terference component. The size of n is N X l .
[0295] (B) Channel estimation
The terminal device 300 estimates a response of a propagation path through which
signals have passed (i.e., a channel response matrix H) in order to equalize, separate,
decode, and the like the signals. For this channel estimation, it is desirable to use an RS
inserted from the transmission side. By using the RS, the radio communication unit
310 acquires an estimation value of H r , which is:
[Math.25]
Expression 25
[0296] (C) Spatial equalization (spatial filtering)
After performing channel estimation, the radio communication unit 310 generates a
reception weighting matrix for spatial equalization corresponding to SDMA, and the
matrix is:
[Math.26]
Expression 26
[0297] Here, the size of the reception weighting matrix is NS I N X. The radio commu
nication unit 310 performs spatial separation by multiplying this reception weighting
matrix by a reception symbol. The output of the spatial separation is expressed with the
following expression by setting the size as the vector of NS l .
[0298] [Math.27]
Expression 27
[0299] Note that, although Expression 27 shows that a linear process based on a weighting
matrix is used, the present technology is not limited thereto. For example, a non-linear
process such as an iterative separation process may be used. In addition, a process si
multaneously performed with the process of (D) to be described next may be
employed. As such processes, for example, joint spatial and power filtering and joint
spatial and power decomposition are considered.
[0300] Note that the processes described above can be performed by the spatial equalization
processing unit 520 shown in FIG. 13.
[0301] (D) SIC, symbol despreading, digital symbol demodulation (or generation of a log
likelihood ratio)
After spatial equalization, the radio communication unit 310 generates a log
likelihood ratio (LLR) per bit equivalent to an interleaved code bit series b " k from
symbols which have undergone digital modulation, symbol spreading, and SPC mul
tiplexing, and the ratio is:
[Math.28]
Expression 28
[0302] As an interference canceller, the radio communication unit 310 may employ a
canceller other than an SIC, for example, a parallel interference canceller (PIC). When
allocation of electric power is performed and an electric power level difference is made
as in SPC, however, an SIC is desirably employed. In addition, when an SIC is
executed, the radio communication unit 310 desirably decodes s"p k corresponding to a
descending order of the highest Ap according to the electric power level Ap of SPC.
[0303] Note that the processes described above can be performed by, the serial-parallel
conversion processing unit 532, the SIC processing units 540, and the serial-parallel
conversion processing unit 542 shown in FIG. 13, and the despreading processing units
550, the demodulation processing units 552, and the serial-parallel conversion
processing unit 560 shown in FIG. 14.
[0304] (E) Deinterleave
After completing generation of the LLR, the radio communication unit 310 restores
the order of bits within the series to the original by executing deinterleave corre
sponding to interleave applied on the transmission side. The series after deinterleave is
expressed with the following expression.
[0305] [Math.29]
Expression 29
[0306] Note that the process described above can be performed by the deinterleavers 562
shown in FIG. 14.
[0307] (F) Error correction decoding
After deinterleave, the radio communication unit 310 acquires the original
transmission bit series by executing decoding corresponding to encoding applied on
the transmission side. The original transmission bit series is expressed with the
following expression.
[0308] [Math.30]
k =DEC ' , , )
Expression 30
[0309] Here, DEC(x) is a function representing decoding.
[0310] Note that the process described above can be performed by the FEC decoding
processing units 570 shown in FIG. 14.
[03 11] (G) Repetitive process
The radio communication unit 310 may repeatedly execute the processes relating to
(C) to (F) described above. In this case, reception and decoding performance can be
enhanced. Particularly, it is desirable to employ a repetitive process for SPC mul
tiplexing and separation of signals multiplexed on non-orthogonal resources.
[0312] Note that the process described above can be performed by the feedback loop
processing unit 580 shown in FIG. 14.
[0313] <3.4. Notification of access setting information>
(Operation process)
A transmission device and a reception device are notified of access setting in
formation indicating a result of allocation by the communication control device 100.
An access setting information notification process with respect to the base station 200
and the terminal device 300 in a cellular system will be described below.
[0314] FIG. 22 is a sequence diagram showing an example of the flow of an access setting
information notification process in the communication system 1 according to the
present embodiment. The present sequence will be introduced on the assumption of
downlink communication in the cellular system.
[0315] As shown in FIG. 22, first in Step S1002, the base station 200 transmits a DL control
channel storing access setting information to the terminal device 300. In the
transmission of the DL control channel, for example, a physical downlink control
channel (PDCCH) is used. In addition, the base station 200 may have received access
setting information from the communication control device 100 beforehand, or the
base station 200 and the communication control device 100 may be integrally formed.
The control unit 330 of the terminal device 300 which have received the DL control
channel controls the radio communication unit 310 to receive a data channel using
allocated resources represented by the access setting information. Accordingly, the
terminal device 300 can receive the DL data channel transmitted from the base station
200. Note that the data channel may be a shared data channel.
[0316] Next, in Step S1004, the base station 200 transmits the DL data channel to the
terminal device 300. At this time, the base station 200 performs the above-described
transmission signal processing according to the access setting information transmitted
in Step S1002. In addition, the terminal device 300 performs the above-described
reception signal processing according to the access setting information received in Step
S1002.
[0317] Next, in Step S1006, the terminal device 300 transmits a positive response (ACK) or
a negative response (NACK) to the base station 200.
[0318] Next, in Steps S1008 to 1012, the base station 200 and the terminal device 300
performs the same processes as the above-described Steps S1002 to S1006. Note that,
when NACK is transmitted in Step S1006 above, Steps S1008 to S10 12 are a r e
transmission process.
[0319] FIG. 23 is a sequence diagram showing an example of the flow of another access
setting information notification process in the communication system 1 according to
the present embodiment. The present sequence will be introduced on the assumption of
uplink communication in the cellular system.
[0320] As shown in FIG. 23, first in Step SI 102, the base station 200 transmits a DL control
channel storing access setting information to the terminal device 300. In the
transmission of the DL control channel, for example, a PDCCH is used. In addition,
the base station 200 may have received the access setting information from the com
munication control device 100 beforehand. The control unit 330 of the terminal device
300 that has received the DL control channel controls the radio communication unit
310 to transmit a data channel or a control channel using allocated resources rep
resented by the access setting information. Accordingly, the terminal device 300 can
transmit a UL data channel to the base station 200.
[0321] Next, in Step SI 104, the terminal device 300 transmits the UL data channel to the
base station 200. At this time, the terminal device 300 performs the above-described
transmission signal processing according to the access setting information received in
Step SI 102 above. In addition, the base station 200 performs the above-described
reception signal processing according to the access setting information transmitted in
Step SI 102 above.
[0322] Next, in Step SI 106, the base station 200 transmits a positive response (ACK) or a
negative response (NACK) to the terminal device 300.
[0323] Next, in Steps S1108 to S1112, the base station 200 and the terminal device 300
perform the same processes as the above-described Steps SI 102 to SI 106. Note that,
when NACK is transmitted in Step SI 106, Steps SI 108 to SI 112 are a re-transmission
process. In addition, Step SI 106 and Step SI 108 described above may be simul
taneously performed in one time of communication.
[0324] Note that, although the processing examples have been described above on the a s
sumption of the cellular system, the present technology may be applied to systems
other than a cellular system. In that case, a transmission device functions as the com
munication control device 100, and the transmission device may notify a reception
device of access setting information.
[0325] (Content of access setting information)
Table 1 below shows a list of information that can be included as access setting in
formation. Access setting information includes at least any of the information shown in
Table 1.
[0326]
[Table 1]
(Method of access setting information notification)
Various notification methods for notifying the base station 200 and the terminal
device 300 of access setting information are considered. Thus, variation in methods of
access setting information notification will be described. Description will be provided
below on the assumption that a notification source of access setting information is the
base station 200 and a notification destination is the terminal device 300; however, a
notification source and a notification destination may be arbitrary devices.
[0328] (1) Batch notification of access setting information for devices
In the present notification method, the base station 200 transmits access setting in
formation to each device in a batch. The terminal device 300 receives the access
setting information transmitted to itself in a batch through the process shown in FIG.
24. FIG. 24 is a flowchart showing an example of the flow of an access setting in
formation reception process executed by the terminal device 300 according to the
present embodiment.
[0329] As shown in FIG. 24, first in Step S1202, the control unit 330 searches for whether
information addressed to the device itself (the terminal device 300) is being transmitted
on a control channel.
[0330] When information addressed to the device has not been found (No in S1204), the
control unit 330 determines in Step S1206 whether or not a search period has elapsed.
When the search period is determined to have elapsed (Yes in S1206), the process
ends. On the other hand, when the search period is determined not to have elapsed (No
in S1206), the process returns to Step S1202 again. Note that, since the control channel
is generally periodically transmitted, the present flow may be executed according to
the period.
[0331] When the information addressed to the device has been found (Yes in S1204), the
control unit 330 reads found information addressed to the device in Step S1208. For
example, the control unit 330 decodes a portion of the control channel in which the in
formation addressed to the device is stored to the final, and reads stored access setting
information. The access setting information that the control unit 330 has read includes,
for example, at least any of the information shown in Table 1 above.
[0332] Next, in Step S1210, the control unit 330 determines whether or not it is also
necessary to read information addressed to another device. This determination can be
performed by referring to, for example, "information regarding another device mul
tiplexing with non-orthogonal resources" included in the access setting information
addressed to the device itself. For example, when there is another device multiplexing
non-orthogonally, the control unit 330 determines that it is also necessary to read in
formation addressed to the other device. In order to perform this determination easily
and at a requisite minimum, it is desirable that a specific ID or RNTI regarding a mul
tiplexing device be included in access setting information. In the present embodiment,
there is a possibility of signals addressed to a plurality of terminal devices 300 being
multiplexed on non-orthogonal resources. When such signals are transmitted or
received, it is desirable for a reception device to know access setting information for
another reception device to be multiplexed on non-orthogonal resources. This is p ar
ticularly advantageous for the terminal device 300 to receive non-orthogonally mul
tiplexed signals.
[0333] When reading the information addressed to another device is determined not to be
necessary (No in S1210), the process ends.
[0334] On the other hand, when reading the information addressed to another device is de
termined to be necessary (Yes in S1210), The control unit 330 searches in Step S1212
for whether information addressed to another device (another terminal device 300) is
being transmitted on the control channel.
[0335] When the information addressed to another device has not been found (No in Step
S1214), the control unit 330 determines in Step S1216 whether or not a search period
has elapsed. When the search period is determined to have elapsed (Yes in S12 16), the
process ends. On the other hand, when the search period is determined not to have
elapsed (No in S1216), the process returns to Step S1212 again. This search period
may be the same as or different from that of Step S1206 above.
[0336] When the information addressed to another device has been found (Yes in S1204),
the control unit 330 reads the found information addressed to another device in Step
S1218. For example, the control unit 330 decodes the portion of the control channel in
which the information addressed to another device is stored to the final, and reads in
formation of the content. The information that the control unit 330 reads includes, for
example, at least any of the information shown in Table 1 above.
[0337] (2) Notification of access setting information to each device in stages
In the present notification method, each device is notified of access setting in
formation in a plurality of stages. For example, access setting information including in
formation regarding orthogonal resources (for example, frequency resources or time
resources) and access setting information including information regarding nonorthogonal
resources (spreading codes, antennas, space streams, electric power levels,
interleave, frequency hopping, error correction codes, or the like) can be separately
notified.
[0338] According to the present notification method, a device which is compatible with a
multiple access scheme using non-orthogonal resources can read information regarding
non-orthogonal resources, and a device which is not compatible with the multiple
access scheme using non-orthogonal resources can omit reading of the information
regarding non-orthogonal resources. For this reason, the present notification method is
useful for maintaining compatibility when devices which are compatible or in
compatible with the multiple access scheme using non-orthogonal resources.
[0339] The base station 200 transmits access setting information to each device in a plurality
of stages. The terminal device 300 gradually receives the access setting information
transmitted to itself in a plurality of stages. For example, the terminal device 300
performs processes in Steps S1208 and S1218 according to the flowchart shown in
FIG. 25 while receiving the access setting information according to the flowchart
shown in FIG. 24 above. FIG. 25 is the flowchart showing an example of the flow of
an access setting information reception process executed in the terminal device 300
according to the present embodiment.
[0340] As shown in FIG. 25, first in Step S1302, the control unit 330 reads the information.
The information read here includes, for example, information regarding orthogonal
resources and other information.
[0341] Next, in Step SI304, the control unit 330 determines whether or not there is more in
formation to be read. The more information to be read includes, for example, in
formation regarding non-orthogonal resources and other information. For example, the
control unit 330 determines that there is more information to be read when the device
itself corresponds to the multiple access scheme using non-orthogonal resources and
the "flag indicating allocation or non-allocation of non-orthogonal resources" is a flag
indicating allocation.
[0342] When it is determined that there is no more information to be read (No in SI304), the
process ends.
[0343] On the other hand, when it is determined that there is more information to be read
(Yes in S1304), the control unit 330 searches for whether more information to be read
is being transmitted on a control channel in Step S1306.
[0344] When no more information to be read has not been found (No in S1308), the control
unit 330 determines whether or not a search period has elapsed in Step S1310. When
the search period is determined to have elapsed (Yes in S1310), the process ends. On
the other hand, when the search period is determined not to have elapsed (No in
S1310), the process returns to Step S1306 again.
[0345] On the other hand, when more information to be read has been found (Yes in S1308),
the control unit 330 reads the found information to be read in Step S1312. For
example, the control unit 330 decodes the portion of the control channel in which the
more information to be read is stored to the final, and reads information of the content.
[0346] (3) Batch notification of access setting information to all devices
The present notification method is to notify all devices of access setting information
in a batch. For example, all devices are notified of the list of access setting information
indicating access settings allocated to the respective devices. As an example, the
present notification method will be described with reference to FIG. 26.
[0347] FIG. 26 is an explanatory diagram for describing the access setting information notification
process according to the present embodiment. In the example shown in FIG.
26, one piece of access setting information is stored in an area which includes one time
resource and one frequency resource (which will also be referred to as, for example, a
resource element or a resource block). In addition, all access setting information is
stored on a control channel. Each device performs signal processing using access
setting information of an area among areas in which its own identification information
(user ID) is written. Note that, in the example shown in FIG. 26, access setting in
formation includes user IDs, time indexes, frequency indexes, space indexes, electric
power indexes, and interleaver indexes. These indexes correspond to information in
dicating allocated orthogonal resources or allocated non-orthogonal resources shown in
Table 1. The access setting information can also include other information shown in
Table 1.
[0348] A merit of the present notification method is that, if the total number of orthogonal
resources and non-orthogonal resources is decided, the amount of control channels for
carrying the information can also be substantially fixed. In other words, unlike other
notification methods, the present notification method can suppress increase of the
amount of control channels according to increase of the number of users. However,
since access setting information can overlap between users, there is a possibility of
overhead being relatively large particularly when the number of users is small. In
addition, in order to know what resources have been allocated to a reading device or
other devices, the device itself has to read all access setting information and refer to
user IDs. An example of an access setting information notification process relating to
the present notification method will be described with reference to FIG. 27.
[0349] FIG. 27 is a flowchart showing an example of the flow of an access setting in
formation reception process executed by the terminal device 300 according to the
present embodiment.
[0350] As shown in FIG. 27, first in Step S1402, the control unit 330 finds access setting in
formation in which its own user ID is written. Accordingly, the control unit can prefer
entially read access setting information for the device itself. Of course, the control unit
330 may find access setting information in which the user ID of another terminal
device 300 is written and set the information as a reading target. The following steps
may be performed in a random order.
[0351] Next, in Step S1404, the control unit 330 reads a time index, a frequency index, a
space index, an electric power index, and an interleaver index included in the access
setting information.
[0352] Next, in Step S1406, the control unit 330 reads information regarding a modulation
scheme and a coding rate included in the access setting information.
[0353] Next, in Step S1408, the control unit 330 reads information regarding a HARQ
included in the access setting information.
[0354] Next, in Step S1410, the control unit 330 reads information regarding a data size
included in the access setting information.
[0355] Next, in Step S1412, the control unit 330 reads information indicating a commu
nication link direction included in the access setting information.
[0356] Next, in Step S1414, the control unit 330 reads information indicating a transmit
power control command included in the access setting information.
[0357] <3.5. Channel configuration>
An example of a channel configuration according to the present embodiment will be
described below with reference to FIGS. 28 to 32. Horizontal axes of each drawing
mean orthogonal resources (for example, frequency, time, etc.) and vertical axes
thereof mean non-orthogonal resources. When frequencies are considered as or
thogonal resources, the orthogonal resources may be subcarriers or resource blocks, or
may be component carriers (CC) of when carrier aggregation (CA) is applied. FIGS.
28 to 32 show arrangements of information regarding orthogonal resources and nonorthogonal
resources allocated to each device (the base station 200 or the terminal
device 300) stored in a control channel. Note that the information regarding orthogonal
resources is information which includes an access scheme using the orthogonal
resources and information indicating the orthogonal resources used in the access
scheme. In addition, the information regarding non-orthogonal resources is information
which includes an access scheme using the non-orthogonal resources and information
indicating the non-orthogonal resources used in the access scheme.
[0358] FIG. 28 is a diagram for describing an example of an arrangement of a control
channel and a data channel according to the present embodiment. In the example i l
lustrated in FIG. 28, information regarding orthogonal resources and information
regarding non-orthogonal resources are included in the same control channel 610. In
addition, the control channel 610 and the data channel 611 are multiplexed using
resources orthogonal to each other. In the present arrangement example, the ar
rangement of the control channel is in a form resembling, for example, general LTE.
[0359] As will be described with reference to FIGS. 29 to 32 below, the information
regarding orthogonal resources and the information regarding non-orthogonal
resources may be included in different control channels. In such a case, different
control channels have at least either different times or different frequencies, and have
predetermined relations with data channels as will be described below.
[0360] FIG. 29 is a diagram for describing an example of an arrangement of control
channels and a data channel according to the present embodiment. In the example i l
lustrated in FIG. 29, the control channel 620 which includes information regarding or
thogonal resources and the control channel 621 which includes information regarding
non-orthogonal resources are multiplexed using resources orthogonal to each other. In
addition, the control channels 620 and 621 and the data channel 622 are multiplexed
using resources orthogonal to each other. The present arrangement example is useful
when each device is notified of access setting information in stages. According to the
present arrangement example, since there is basically no interference between the
channels, it is possible to avoid deteriorating accuracy in decoding. In addition,
according to the present arrangement example, the communication system 1 can ac
commodate a legacy device that is not compatible with a multiple access scheme using
non-orthogonal resources. In addition, according to the present arrangement example,
since the control channel 620 and the control channel 621 are in an orthogonal relation,
a legacy device that is not compatible with a multiple access scheme using nonorthogonal
resources can read information regarding orthogonal resources without
problem.
[0361] FIG. 30 is a diagram for describing an example of an arrangement of control
channels and a data channel according to the present embodiment. In the example i l
lustrated in FIG. 30, the control channel 630 which includes information regarding or
thogonal resources and the control channel 631 which includes information regarding
non-orthogonal resources are multiplexed using resources orthogonal to each other. In
addition, the control channel 630 is multiplexed with the data channel 632 using
resources orthogonal to each other. In addition, the control channel 631 is multiplexed
with the data channel 632 using resources at least orthogonal or non-orthogonal to each
other. Since the control channel 630 which includes the information regarding nonorthogonal
resources is information that is read by a device which is compatible with a
multiple access scheme using non-orthogonal resources, the control channel 630 and
the data channel 632 may be non-orthogonally multiplexed. In addition, according to
the present arrangement example, since the control channel 630 and the control
channel 631 are in an orthogonal relation, a legacy device that is not compatible with a
multiple access scheme using non-orthogonal resources can read the information
regarding orthogonal resources without problem.
[0362] FIG. 3 1 is a diagram for describing an example of an arrangement of control
channels and a data channel according to the present embodiment. In the example i l
lustrated in FIG. 31, the control channel 640 which includes information regarding or
thogonal resources and the control channel 641 which includes information regarding
non-orthogonal resources are multiplexed using resources non-orthogonal to each other
on the same orthogonal resources. In addition, the control channels 640 and 641 are
multiplexed with the data channel 642 using resources orthogonal to each other.
According to the present arrangement example, the control channel 640 and the control
channel 641 can interfere with each other. For this reason, although a result of reading
the control channel 640 by a legacy device that is not compatible with a multiple
access scheme using non-orthogonal resources can deteriorate, it is not necessary to
change a decoding mechanism.
[0363] FIG. 32 is a diagram for describing an example of an arrangement of control
channels and a data channel according to the present embodiment. In the example i l
lustrated in FIG. 32, the control channel 650 which includes information regarding or
thogonal resources and the data channel 652 are multiplexed using resources or
thogonal to each other. In addition, the control channel 651 which includes information
regarding non-orthogonal resources and the control channel 650 are multiplexed using
resources at least orthogonal or non-orthogonal to each other. In addition, the control
channel 651 and the data channel 652 are multiplexed using resources at least or
thogonal or non-orthogonal to each other.
[0364] As an example of the non-orthogonal resources of the vertical axes in FIGS. 28 to 32,
an electric power level is exemplified. In this case, different electric power levels can
be allocated to the control channels which include information regarding orthogonal
resources, control channels which include information regarding non-orthogonal
resources, and data channels. Since the control channels are important for accurately
decoding the subsequent data channels (not necessarily immediately subsequent
thereto), electric power levels can be adjusted to enable the control channels to be ap
propriately decoded first. Note that a magnitude relation of electric power levels
allocated to respective channels may coincide with or may be different from the
magnitude relations shown in FIGS. 28 to 32.
[0365] Here, levels or unit densities of electric power allocated to transmission of respective
control channels and data channels may have a predetermined magnitude relation as
described below. PCCHO indicates a level or a unit density of electric power of a control
channel which includes information regarding orthogonal resources and information
regarding non-orthogonal resources. PCCHI indicates a level or a unit density of electric
power of a control channel which includes information regarding orthogonal resources.
PCCH2 indicates a level or a unit density of electric power of a control channel which
includes information regarding non-orthogonal resources. In addition, PSCH indicates a
level or a unit density of electric power of a data channel per unit, and when a plurality
of pieces of data are non-orthogonally multiplexed, indicates a level or a unit density
of electric power of the sum of them. Since it is desirable for control channels to be
decodable in terms of a stable system operation, it is desirable to satisfy the conditions
of the following expression as magnitude relations thereof.
[0366]
[Math.31]
P > P
P c m >— Psen
rPCCHl > PCCH2
Expression 3 1
[0367] As shown by Expression 3 1 above, a level or a unit density of electric power
allocated to transmission of a control channel which includes information regarding or
thogonal resources is desirably equal to or higher than a level or a unit density of
electric power allocated to transmission of a data channel. In addition, as shown by Ex
pression 3 1 above, a level or a unit density of electric power allocated to transmission
of a control channel which includes information regarding orthogonal resources is
desirably equal to or higher than a level or a unit density of electric power allocated to
transmission of a control channel which includes information regarding non-or
thogonal resources.
[0368] Furthermore, although not illustrated, a level or a unit density of electric power is
considered by being divided into electric power of a data channel transmitted using or
thogonal resources PSCH,O and electric power of a data channel transmitted using nonorthogonal
resources PSCH,NO t is desirable to satisfy the conditions of the following
expression.
[0369] [Math.32]
PCCHQ >— PSCH, NO
P
CCHl —
> P
SCH, O
PCCH2 > P
SCH 0
Expression 32
[0370] <3.6. Capability information>
(Content of capability information)
Table 2 below shows an example of capability information.
[Table 2]
[0371] As shown in Table 2 above, capability information includes information indicating
whether or not a device is compatible with each of orthogonal resources and nonorthogonal
resources. For example, capability information can include information in
dicating whether a device is compatible (OK) or incompatible (NG) with each access
scheme. The information may be realized as bit flags. In addition, capability in
formation can include a user IDs as identification information of a device itself. The
terminal device 300 specifies each base station 200 or terminal device 30 using a user
ID, and thereby knows with what access scheme the specified device is compatible.
Note that "3G" and "4G" in Table 2 above can also be understood as legacy RATs.
[0372] (Notification of capability information)
An example of the procedure of notification of capability information will be
described below with reference to FIG. 33.
[0373] FIG. 33 is a sequence diagram showing the example of the flow of a capability in
formation notification process executed in the communication system 1 according to
the present embodiment. As shown in FIG. 33, the terminal device 300, the base
station 200, and the communication control device 100 are involved in the present
sequence.
[0374] The processes relating to Steps S1502 to S1510 shown in FIG. 33 are a procedure for
establishing radio resource control (RRC) connection. Specifically, in Step SI502, the
terminal device 300 transmits a random access preamble to the base station 200. The
base station 200 which has succeeded in receiving the random access preamble
transmits a random access response to the terminal device 300 in Step S1504. Through
this step, the base station 200 recognizes the terminal device 300. Next, in Step S1506,
the terminal device 300 transmits an RRC connection request message to the base
station 200. The base station 200 which has succeeded in receiving the RRC
connection request message transmits an RRC connection setup message to the
terminal device 300 in Step S1508. The terminal device 300 sets a parameter according
to setup information included in the RRC connection setup message received from the
base station 200, and then transmits an RRC connection setup completion message to
the base station 200 in Step S1510.
[0375] Through the procedures of random access and RRC connection described above, c a
pability information may be transmitted from the terminal device 300 and received by
the base station 200. For example, the terminal device 300 may transmit a message
dedicated to notifying the base station 200 of the capability information. In addition,
the terminal device 300 may include the capability information in at least any of the
messages transmitted to the base station 200 in the procedure relating to Steps S1502
to S1510 above. Specifically, the terminal device 300 may include the capability in
formation in at least any of the random access preamble, the RRC connection request
message, any the RRC connection setup message. In this case, overhead can be
reduced more than when the capability information is transmitted using a dedicated
message. The reason is that there is a possibility of the capability information being
settled with several bits as shown in Table 2 above.
[0376] Next, in Step S1512, the base station 200 transmits capability information to the
communication control device 100. At this time, the base station 200 transmits the c a
pability information received from the terminal device 300. In addition, the base
station 200 may transmit its own capability information to the communication control
device 100.
[0377] Next, in Step S1514, the communication control device 100 transmits a reception
completion response to the base station 200. The communication control device 100
may share the capability information collected in Step S1512 above with another com
munication control device on a core network or another network. In this case, in the
procedure of cell selection and handover to be described below, the capability in
formation can be used more effectively.
[0378] Table 3 below shows an example of capability information collected from a plurality
of devices.
[Table 3]
It is desirable for the terminal device 300 to store the capability information collected
in Step S1512 above with the user ID. Here, as an entity functioning as the terminal
device 300 on the core network, for example, a mobility management entity (MME) is
exemplified. Since an MME has a function of controlling cell selection and handover
of the terminal device 300, it is useful for retaining capability information of the
plurality of devices shown in Table 3. In addition, the base station 200 may retain the
capability information of the terminal device 300 which belongs to the cell operated by
the base station.
As described above, the base station 200 may notify the communication control
device 100 of its own capability information. Table 4 below shows an example of the
capability information of the base station 200.
[Table 4]
[0381] As shown in Table 4, the capability information of the base station 200 may be in the
same form as the capability information of the terminal device 300 shown in Table 3
above, and a cell ID may be used as identification information.
[0382] In addition, the base station 200 may notify the communication control device 100 of
status information indicating what access scheme is being currently used, in addition to
its own capability information. Table 5 below shows an example of the status in
formation of the base station 200.
[Table 5]
[0383] In Table 5, an access scheme that is currently being used is marked with "Enabled"
and an access scheme that is currently not being used is marked with "Disabled." As
shown in Table 5 above, the status information can include information indicating each
access scheme being used (Enabled) or not being used (Disabled). The information
may be realized as bit flags.
[0384] (Procedure in which capability information is used)
Next, a procedure in which capability information is used will be described. As an
example of the procedure, the procedure of handover and the procedure of admission
control using capability information will be described. As will be described below, the
communication control device 100 or the base station 200 uses capability information
of the terminal device 300 in the procedure of handover of the terminal device 300 or
the procedure of admission control. In addition, the communication control device 100
or the base station 200 further uses capability information of the base station 200 that
is a handover destination candidate in the procedure of handover of the terminal device
300 or the procedure of admission control.
[0385] FIG. 34 is a sequence diagram showing an example of the flow of a handover process
executed in the communication system 1 according to the present embodiment. As
shown in FIG. 34, the terminal device 300, base stations 200A and 200B, and the com
munication control device 100 are involved in the present sequence. Note that the base
station 200A is a base station serving as a handover source (for example, a source
eNB), and the base station 200B is a base station serving as a handover destination
candidate (for example, a target eNB).
[0386] First, in Step S1602, the terminal device 300 performs measurement. For example,
the terminal device 300 receives, for example, a predetermined reference signal,
broadcast signal, synchronizing signal, or the like periodically transmitted from the
base station 200. At this time, the terminal device 300 measures a signal intensity (for
example, Reference Signal Received Power (RSRP), Received Signal Strength
Indicator (RSSI), or the like), signal quality (for example, Reference Signal Received
Quality (RSRQ), and the like), and the like.
[0387] Next, in Step S1604, the terminal device 300 transmits the measurement information
to the base station 200A to which the device is being connected or which is operating a
cell to which the device belongs. The terminal device 300 performs the transmission in
a periodic manner or according to an instruction from the base station 200A.
[0388] Next, in Step S1606, the base station 200A checks the measurement information. For
example, when the measurement information meets a predetermined condition, the
base station 200A starts a process of checking feasibility of handover that will be
described below.
[0389] Next, in Step SI608, the base station 200A transmits a handover trigger (Handover
Required) to the communication control device 100.
[0390] Next, in Step S1610, the communication control device 100 checks the capability in
formation. For example, when the communication control device 100 collates the c a
pability information of the terminal device 300 and a base station 200 relating to
handover of the terminal device 300 and the information meets a predetermined
condition, the communication control device starts a process of transiting to execution
of handover that will be described below. In addition to the capability information, the
communication control device 100 may refer to status information of the base station
200 relating to the handover. As the base station 200 relating to the handover, the base
station 200A that is a handover source to which the terminal device 300 currently
belongs and the base station 200B which is a handover destination candidate operating
a cell. Note that details of the process of this step will be described below.
[0391] Next, in Step S1612, the communication control device 100 transmits a handover
request (Handover Request) to the base station 200B which is a handover destination
candidate. Further, when an access setting allocated to the base station 200B is to be
changed, the communication control device 100 transmits an access setting change
request which is a message indicating a change of allocation of the access setting to the
base station 200B. For example, the communication control device 100 can change the
access setting so that the access setting, which is usable by the terminal device 300 but
is not currently being used by the base station 200B, can be newly used. The access
setting change request can include, for example, post-change access setting in
formation. The base station 200B can know an access scheme and resources to start
using and an access scheme and resources to stop using, by referring to the access
setting change request.
[0392] Next, in Step S1614, the base station 200B performs admission control (Admission
Control). For example, the base station 200B determines whether or not acceptance of
handover and a change of the access setting are possible. At this time, the base station
200B can determine the possibility of handover according to the result of the change
possibility determination of the access setting. Note that details of the process of this
step will be described below. When the base station 200B determines acceptance of
handover and a change of the access setting to be possible, for example, the base
station starts a process of executing handover that will be described below.
[0393] The communication control device 100 receives a message indicating the result of
the change possibility determination of the access setting of the base station 200B that
is for the access setting change request. For example, when acceptance of handover
and the change of the access setting are determined to be possible, for example, the
base station 200B transmits a message indicating approval for the handover request to
the communication control device 100 in Step S1616. The message indicating approval
for the handover request may also serve as a message indicating approval for the
access setting change request.
[0394] Next, in Step S1618, the communication control device 100 transmits a handover
command (Handover Command) to the base station 200A.
[0395] Next, in Step SI620, the base station 200A transmits a handover command and an
RRC connection resetting command (RRC connection reconfiguration) to the terminal
device 300.
[0396] Here, if the base station 200A supports so-called seamless handover and data remains
to be transmitted and received, the base station 200A transfers the remaining data to
the base station 200B in Step SI 622.
[0397] Next, in Step SI 624, the terminal device 300 transmits a random access preamble to
the base station 200B. The base station 200B which has succeeded in receiving the
random access preamble transmits a random access response to the terminal device 300
in Step S1626. Next, in Step S1628, the terminal device 300 performs a resetting of
RRC connection (RRC connection reconfiguration), and transmits a message of RRC
connection resetting completion (RRC connection reconfiguration complete) to the
base station 200B. Accordingly, handover is completed, and continuation of the com
munication service starts.
[0398] As described above, the terminal device 300 may transmit a message dedicated to
notifying the base station 200B of capability information. In addition, the terminal
device 300 may include capability information in at least any of the random access
preamble and the message of RRC connection resetting completion. Note that when a
base station 200 manages capability information, it is desirable that notification of the
capability information be made each time a connection destination of the terminal
device 300 changes, i.e., each time handover occurs.
[0399] Next, in Step SI 630, the base station 200B transmits the capability information
received from the terminal device 300 to the communication control device 100. In
addition, the base station 200B may transmit its own capability information and status
information to the communication control device 100.
[0400] Next, in Step S1632, the communication control device 100 transmits a reception
completion response to the base station 200B.
[0401] Although the example in which the communication control device 100 checks the c a
pability information in Step S1610 has been described above, the present technology is
not limited thereto. For example, a base station 200 may check the capability in
formation. In addition, although the example in which the base station 200B performs
admission control in Step S1614 has been described above, the present technology is
not limited thereto. For example, the communication control device 100 may perform
admission control. As an example, a case in which a base station 200 checks capability
information will be described with reference to FIG. 35.
[0402] FIG. 35 is a sequence diagram showing an example of the flow of a handover process
executed in the communication system 1 according to the present embodiment. As
shown in FIG. 35, the terminal device 300, base stations 200A and 200B, and the com
munication control device 100 are involved in the present sequence. Note that the base
station 200A is a base station serving as a handover source (for example, a source
eNB), and the base station 200B is a base station serving as a handover destination
candidate (for example, a target eNB).
[0403] First, in Step S1702, the terminal device 300 performs measurement. Next, in Step
S1704, the terminal device 300 transmits measurement information to the base station
200A. Next, in Step S1706, the base station 200A checks the measurement in
formation.
[0404] Then, in Step S1708, the base station 200A checks capability information. The base
station 200A may refer to status information of a base stations 200 relating to
handover, in addition to the capability information.
[0405] Next, in Step S1710, the base station 200A transmits a handover request to the base
station 200B serving as a handover destination candidate. Further, the base station
200A transmits an access setting change request to the base station 200B when a
change of an access setting is to be requested.
[0406] Next, in Step S1712, the base station 200B performs admission control. When ac
ceptance of handover and a change of an access setting are determined to be possible,
the base station 200B transmits a message indicating approval for the handover request
to the base station 200A in Step S1714. Since the processes of the following Steps
S1716 to S1724, S1728, and S1730 are the same as those of Steps S1620 to S1632
described with reference to FIG. 34, description thereof will be omitted herein. In
addition to the processes of Steps SI620 to SI632 described with reference to FIG. 34,
the base station 200B transmits a handover status report indicating a handover result to
the communication control device 100 in Step S1726.
[0407] Although the example in which the predetermined condition is determined to be met
through checking of capability information and the process of transiting to execution of
handover is started has been describe in FIGS. 34 and 35 above, the converse example
will be described below.
[0408] FIG. 36 is a sequence diagram showing an example of the flow of a handover process
executed in the communication system 1 according to the present embodiment. As
shown in FIG. 36, the terminal device 300, the base stations 200A and 200B, and the
communication control device 100 are involved in the present sequence. The present
sequence corresponds to the sequence shown in FIG. 34.
[0409] Since the processes of Steps S1802 to S1810 are the same as those of Steps S1602 to
S1610 described with reference to FIG. 34, description thereof will be omitted. Upon
determining a predetermined condition not to be met as a result of checking capability
information in Step S1810, the communication control device 100 starts a process of
rejecting handover that will be described below. For example, when access schemes
and resources with which the terminal device 300 is compatible do not overlap access
schemes and resources with which the base station 200B is compatible, the commu
nication control device 100 starts the process of rejecting handover.
[0410] In Step S1812, the communication control device 100 first transmits a message in
dicating rejection of handover to the base station 200A. The base station 200A which
has received the message does not transmit a handover command to the terminal
device 300. Instead, the base station 200A may transmit, for example, a message in
dicating rejection of handover to the terminal device 300 in Step S1814.
[041 1] FIG. 37 is a sequence diagram showing an example of the flow of a handover process
executed in the communication system 1 according to the present embodiment. As
shown in FIG. 37, the terminal device 300 and the base station 200A are involved in
the present sequence. The present sequence corresponds to the sequence shown in FIG.
35.
[0412] Since the processes of Steps S1902 to S1908 are the same as those of Steps S1702 to
S1708 described with reference to FIG. 35, description thereof will be omitted. Upon
determining a predetermined condition not to be met as a result of checking capability
information in Step S1908, the base station 200A rejects handover. For example, the
base station 200A does not transmit a handover command to the terminal device 300.
Instead, the base station 200A may transmit, for example, a message indicating
rejection of handover to the terminal device 300 in Step S1910.
[0413] In addition, although the example in which the acceptance of handover and a change
of an access setting are determined to be possible and the process of transiting to
execution of handover is started in admission control has been describe in FIGS. 34
and 35 above, the converse example will be described below.
[0414] FIG. 38 is a sequence diagram showing an example of the flow of a handover process
executed in the communication system 1 according to the present embodiment. As
shown in FIG. 36, the terminal device 300, the base stations 200A and 200B, and the
communication control device 100 are involved in the present sequence. The present
sequence corresponds to the sequence shown in FIG. 38.
[0415] Since the processes of Steps S2002 to S2014 are the same as those of Steps S1602 to
S1614 described with reference to FIG. 34, description thereof will be omitted. When
the base station 200B determines acceptance of handover and a change of an access
setting are not possible in admission control of Step S2014, the base station starts a
process of rejecting handover to be described below.

Claims
A control device comprising:
circuitry configured to
communicate with a radio communication device of a radio commu
nication system equipped to use a plurality of alternative access
schemes, the plurality of alternative access schemes including at least
one of a multiple access scheme that uses orthogonal resources and a
multiple access scheme that uses non-orthogonal resources, and
allocate resources according to a selected access scheme of the plurality
of alternative access schemes.
The control device according to claim 1, wherein the circuitry is
configured to specify which of the plurality of alternative access
schemes the radio communication device is to use.
The control device according to claim 1, wherein the circuitry is further
configured to include information in one or more control channels
regarding the orthogonal resources and the non-orthogonal resources to
be allocated to the radio communication device.
The control device according to claim 3, wherein the one or more
control channels include at least two different control channels with at
least different times and/or different frequencies, and having different
predetermined respective relationships with data channels.
The control device according to claim 4, wherein levels or unit
densities of electric power allocated to transmission of the at least two
different control channels and respective data channels have a prede
termined magnitude relation.
The control device according to claim 5, wherein a level or unit density
of electric power allocated to transmission a control channel of the two
different control channels which includes information regarding the or
thogonal resources is equal to or higher than a level or unit density of
electric power allocated to transmission of a corresponding data
channel.
The control device according to claim 5, wherein the level or the unit
density of electric power allocated to transmission of a control channel
of the two different control channels which includes information
regarding the orthogonal resources is equal to or higher than a level or a
unit density of electric power allocated to transmission of a control
channel of the two different control channels which includes inPCT/
JP2015/005488
formation regarding the non-orthogonal resources.
The control device according to claim 1, wherein the circuitry is
configured to receive capability information from the radio commu
nication device.
The control device according to claim 8, wherein the circuitry is
configured to receive the capability information via a random access
protocol scheme or a RRC connection scheme.
The control device according to claim 8, wherein the circuitry is
configured to transfer the capability information of the radio commu
nication device to another device.
The control device according to claim 8, wherein the circuitry is
configured to use the capability information of the radio commu
nication device in a handover procedure of the radio communication
device or admission control procedure.
The control device according to claim 11, wherein the circuitry is
further configured to use the capability information of a base station
serving as a handover destination candidate with respect to the radio
communication device.
The control device according to claim 8, wherein the capability in
formation includes a bit flag indicating whether or not a device is
compatible with each of the orthogonal resources and the nonorthogonal
resources.
The control device according to claim 1, wherein the circuitry is
configured to transmit a message indicating a change in allocation to
the radio communication device.
The control device according to claim 14, wherein the circuitry is
configured to receive a message indicating a result of change pos
sibility determination with respect to the radio communication device
according to the message indicating a change in allocation.
The control device according to claim 15, wherein the circuitry is
configured to determine a handover possibility according to the result
of the change possibility determination.
The control device according to claim 1, wherein the circuitry is
configured to transmit information indicating an allocation result by the
circuitry to the radio communication device.
The control device according to claim 1, wherein the circuitry is
configured to allocate different or shared resources to one or more radio
communication devices.
WO 2016/092738 PCT/JP2015/005488
[Claim 19] A radio communication device comprising:
circuitry configured to
perform radio communications using a plurality of alternative access
schemes, the plurality of alternative access schemes including at least
one of a multiple access scheme that uses orthogonal resources and a
multiple access scheme that uses non-orthogonal resources, and
control a radio communication device to perform radio communication
using allocated resources for the access schemes selected for use by the
circuitry.
[Claim 20] A communication control method comprising:
using circuitry to perform communications with a radio communication
device of a radio communication system equipped to use a plurality of
alternate access schemes, the plurality of alternate access schemes
including at least one of a multiple access scheme that uses orthogonal
resources and a multiple access scheme that uses non-orthogonal
resources; and
allocating with the circuitry resources according to a selected access
scheme of the plurality of alternative access schemes.