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Description
Title of Invention
BASE STATION, METHOD FOR RADIO COMMUNICATION, PROGRAM,
5 RADIO COMMUNICATION SYSTEM, AND RADIO TERMINAL
Technical Field
[0001]
The invention relates to a base station, a method for radio communication, a
10 program, a radio communication system, and a radio terminal.
Background Art
[0002]
Currently, standardization of a 4G radio communication system is under
15 progress by 3GPP (Third Generation Partnership Project). According to the 4Q an
improvement in maximum communication speed and a quality improvement in cell
edges can be realized by using technologies such as relays and carrier aggregation.
Further, considerations are given to improving coverage by introducing base stations
other than eNodeB (macro-cell base station), such as HeNodeB (Home eNodeB,
20 femtocell base station, compact base station for cell phones) and RHH (Remote
Radio Head).
[0003]
(Blind Decoding)
In a radio communication system as above, the base station notifies an
25 assignment of a receiver resource to a UE (Downlink Assign), a grant of a transmitter
resource (Uplink Grant) and the like by a control signal called PDCCH (Phy
Downlink Control Channel). Here, resource information such as the Downlink
Assign and the Uplink Grant are information for each UE (User Equipment). Due
to this, the base station transmits the control signal so that each UE can extract the
30 resource information addressed to itself, and each ,UE extracts the resource
information addressed to itself from the PDCCH by a process called blind decoding.
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Hereinbelow, this feature will be described in detail.
[0004]
The base station describes resource information addressed to each UE in
smallest units of the control signal called CCE (Control Channel Element). Further,
5 the base station adds, to the CCE, check bits that are obtained by CRC (Cyclic
Redundancy Check) by masking the resource information with C-RNTI (Cell Radio
, Network Temporary Identify) that is an identifier unique to each UE.
[0005]
When the PDCCH including a plurality of the aforementioned CCEs is
10 received, the UE performs the CRC check by demasking each CCE by the UE's own
C-RNTI. That is, the UE performs the CRC check of each CCE on an assumption
that each CCE is addressed to itself, and determines the CCE with a normal result as
the CCE addressed to itself The above process by the UE is called the blind
decoding, and such a blind decoding is described for example in Patent Literature 1.
15 [0006]
(MTC)
On the other hand, debates on MTC (Machine Type Communications) ane
also in progress in the 3GPP. The MTC is generally synonymous to M2M
(Machine to Machine), and refers to a communication between machines and not .
20 directly used by a human. The MTC primarily is performed between a server and a
MTC terminal that is not directly used by a human.
[0007]
For example, as a medical application of the MTC, a case may be assumed
in which an MTC terminal collects electrocardiogram information of a human, and
25 traiismits the electrocardiogram information to a server by using uplink when a
certain trigger condition is met. As another application of the MTC, a case may be
assumed in which a vending machine is caused to function as an MTC terminal, and
a server causes the vending machine under management to report sales once every
certain cycle (for example, every 30 days).
30 [0008]
Such an MTC terminal by way of example has the following features in
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general, however, not every MTC terminal needs to have all of the following features,
and which of the features is to be endowed depends on applications.
Scarce needs to move (Low Mobility)
Transmission of small data (Online Small Data Transmission)
5 - Very low power consumption (Extra Low Power Consumption)
Handled by grouping respective MTCs (Group-based MTC Features)
Citation List
Patent Literature
10 [0009]
Patent Literature 1: JP 2009-296589A
Summary of Invention
Technical Problem
15 [0010]
However, due to the introduction of the aforementioned MTCs, increases
are expected in a number of terminals existing within each cell, a number of
terminals a base station is to contain in an Active mode, and a number of terminals
for the base station to simultaneously control in the PDCCH. Further, the CCE
20 included in the PDCCH also increases accompanying the increase in the number of
terminals simultaneously controlled in the PDCCH.
[0011]
As a result, load of the blind decoding in the UE increases due to a range
requiring the blind decoding by the UE (including the MTC terminal) being broader.
25 Especially, there are cases in which the extra-low power consumption is required in
the MTC terminal, so the increase in the load of the blind decoding is problematic.
[0012]
The invention has been created in view of the above problem, and an aim of
the invention is to provide a novel and improved base station, method for radio
30 communication, program, radio communication system, and radio terminal capable
of suppressing the load of the blind decoding in the radio terminal.
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Solution to Problem
[0013]
According to an embodiment of the present disclosure, there is provided a
base station including a transmitter section that transmits a radio signal in a frame
5 including a control region and a data region, a control signal generating section that
generates a control signal which includes reference information identified by a group
identifier assigned to a plurality of radio terminals and which is transmitted in the
control region, and a data signal generating section that generates a data signal by
disposing information for the plurality of radio terminals in a reference region
10 indicated by the reference information in the data region.
[0014]
The data signal generating section may dispose information for each of the
plurality of radio terminals in the reference region indicated by the reference
information, the information being identified by a terminal identifier of each of the
15 plurality of radio terminals.
[0015]
The information for each of the plurality of radio terminals may include
uplink resource information or downlink resource information.
[0016]
20 The uplink resource information or the downlink resource information may
indicate a resource in a fi-ame that is provided after a fi-ame in which the information
for each of the plurality of radio terminals is disposed.
[0017]
The data signal generating section may dispose the information for the
25 plurality of radio terminals in a same reference region within the data region over a
plurality of frames, the same reference region being indicated by the reference
information disposed in a control region of one frame.
[0018]
An uplink group identifier and a downlink group identifier may be assigned
30 to the plurality of radio terminals, the data signal generating section may dispose
uplink resource information for each of the plurality of radio terminals in a reference
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region indicated by reference information identified by the uplink group identifier,
and the data signal generating section may dispose downlink resource information
for each of the plurality of radio terminals in a reference region indicated by
reference information identified by the downlink group identifier.
5 [0019]
The control signal generating section may dispose reference information
identified by a same group identifier in a predetermined frequency region within the
control region.
[0020]
10 The control signal generating section may add a check bit obtained by
masking the reference information with the group identifier to the reference
information.
[0021]
According to another embodiment of the present disclosure, there is
15 provided a method for radio communication, the method including the steps of
generating a control signal that is to be transmitted in a control region in a fi^ame
including the control region and a data region, the control signal including reference
information identified by a group identifier assigned to a plurality of radio terminals,
generating a data signal by disposing information for the plurality of radio terminals
20 in a reference region indicated by the reference information in the data region, and
transmitting the control signal and the data signal.
[0022]
According to another embodiment of the present disclosure, there is
provided a program for causing a computer to function as a transmitter section that
25 transmits a radio signal in a frame including a control region and a data region, a
control signal generating section that generates a control signal which includes
reference information identified by a group identifier assigned to a plurality of radio
terminals and which is transmitted in the control region, and a data signal generating
section that generates a data signal by disposing information for the plurality of radio
30 terminals in a reference region indicated by the reference information in the data
region.
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[0023]
According to another embodiment of the present disclosure, there is
provided a radio communication system including a plurality of radio terminals, and
a base station that includes a transmitter section that transmits a radio signal in a
5 frame including a control region and a data region, a control signal generating
section that generates a control signal which includes reference information
identified by a group identifier assigned to the plurality of radio terminals and which
is transmitted in the control region, and a data signal generating section that
generates a data signal by disposing information for the plurality of radio terminals in
10 a reference region indicated by the reference information in the data region.
[0024]
According to another embodiment of the present disclosure, there is
provided a radio terminal including a receiver section that receives a radio signal
transmitted from a base station in a frame including a control region and a data
15 region, and an acquiring section that acquires reference information identified by a
group identifier assigned to a plurality of radio terminals including the radio terminal
from a control signal received in the control region, and a data portion identified by a
terminal identifier assigned to the radio terminal from a data signal received in a
reference region indicated by the reference information in the data region.
20 [0025]
The acquiring section may acquire the data portion identified by the
terminal identifier assigned to the radio terminal from the control signal received in
the control region in a case of determining that the group identifier is not used by the
base station.
25 [0026]
According to another embodiment of the present disclosure, there is
provided a method for radio communication performed by a radio terminal, the
method including the steps of receiving a radio signal transmitted from a base station
in a frame including a control region and a data region, acquiring reference
30 information identified by a group identifier assigned to a plurality of radio terminals
including the radio terminal from a control signal received in the control region, and
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acquiring a data portion identified by a terminal identifier assigned to the radio
terminal from a data signal received in a reference region indicated by the reference
information in the data region.
[0027]
5 According to another embodiment of the present disclosure, there is
provided a program for causing a computer to function as a radio terminal that
includes a receiver section that receives a radio signal transmitted from a base station
in a frame including a control region and a data region, and an acquiring section that
acquires reference information identified by a group identifier assigned to a plurality
10 of radio terminals including the radio terminal from a control signal received in the
control region, and a data portion identified by a terminal identifier assigned to the
radio terminal from a data signal received in a reference region indicated by the
reference information in the data region.
15 Advantageous Effects of Invention
[0028]
According to the invention as described above, the load of the blind
decoding in the radio terminal can be suppressed.
20 Brief Description of Drawings
[0029]
[Fig. 1] FIG. 1 is an explanatory diagram showing an example of a configuration of a
radio communication system.
[Fig. 2] FIG. 2 is an explanatory diagram showing a 4G frame format.
25 [Fig. 3 A] FiG. 3 A is an explanatory diagram showing an example of using one Ofdm
symbol in a transmission of a PDCCH.
[Fig. 3B] FIG. 3B is an explanatory diagram showing an example of using two Ofdm
symbols in the transmission of the PDCCH.
[Fig. 3C] FIG. 3C is an explanatory diagram showing an example of using three
30 Ofdm symbols in the transmission of the PDCCH.
[Fig. 4] FIG. 4 is an explanatory diagram showing a resource block.
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[Fig. 5] FIG. 5 is an explanatory diagram showing a specific example of a CCE.
[Fig. 6] FIG. 6 is an explanatory diagram showing blind decoding.
[Fig. 7] FIG. 7 is an explanatory diagram showing the blind decoding.
[Fig. 8] FIG. 8 is a sequence diagram showing an example of a method of assigning
5 C-RNTI and MTC-GP_RNTI.
i
[Fig. 9] FIG. 9 is an explanatory diagram showing a configuration of a base station of
a first embodiment of the invention.
[Fig. 10] FIG. 10 is an explanatory diagram showing a dispositional relationship of a
CCE, a second search space, and an allotted resource.
10 [Fig. 11] FIG. 11 is an explanatory diagram showing a configuration of an MTC
terminal of the first embodiment.
[Fig. 12] FIG. 12 is a sequence diagram showing an operation of the radio
communication system of the first embodiment of the invention.
[Fig. 13] FIG. 13 is a sequence diagram showing an example of a method of
15 changing an RNTI used for the blind decoding.
[Fig. 14] FIG. 14 is an explanatory diagram showing an example of disposition of the
second search space for a certain MTC group.
[Fig. 15] FIG. 15 is an explanatory diagram showing an example of disposition of the
CCE for each MTC group.
20 [Fig. 16] FIG. 16 is an explanatory diagram showing a specific example of an MTC
group to which MTC terminals belong.
[Fig. 17] FIG. 17 is an explanatory diagram corresponding to a fourth embodiment.
[Fig. 18] FIG. 18 is an explanatory diagram showing a relationship of a reference
resource block and an uplink resource block of each MTC terminal.
25 [Fig. 19] FIG. 19 is an explanatory diagram showing a modification of the
relationship of the reference resource block and the uplink resource block of each
MTC terminal.
[Fig. 20] FIG. 20 is an explanatory diagram showing an operation of a radio
communication system of a fifth embodiment.
30
Description of Embodiments
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[0030]
Hereinafter, preferred embodiments of the present invention will be
described in detail with reference to the appended drawings. Note that, in this
specification and the drawings, elements that have substantially the same flinction
5 and structure are denoted with the same reference signs, and repeated explanation is
omitted.
[0031]
Further, in the description and the drawings, there may also be cases in
which a plurality of constituent features having substantially the same functional
10 configuration is distinguished by adding different alphabets after the same reference
sign. For example, the plurality of constituent features having substantially the
same functional configuration may be distinguished as MTC terminals 20A, 20B,
and 20C. However, in cases where the respective one of the plurality of constituent
features having substantially the same functional configuration does not need to be
15 particularly distinguished, only the same reference sign will be given. For example,
when the MTC terminals 20A, 20B, and 20C do not particularly need to be
distinguished, each will simply be termed a MTC terminal 20.
[0032]
Further, the "mode to carry out the invention" will be described in
20 accordance with the order in the below appendix.
1. Overview of Radio Communication System
1-1. Overview of radio communication system
1-2. Configuration of frame
1 -3. Configuration of PDCCH
25 1-4. Blind decoding
2. Description of Respective Embodiments
2-1. First embodiment
(Base station of first embodiment)
(MTC terminal of first embodiment)
30 (Operation of first embodiment)
(Supplementation of first embodiment)
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2-2. Second embodiment
2-3.. Third embodiment
2-4. Fourtli embodiment
2-5. Fifth embodiment
5 2-6. Sixth embodiment
2-7. Seventh embodiment
3. Conclusion
[0033]
<1. Overview of Radio Communication System>
10 Currently, standardization of a 4G radio communication system is in
progress in 3 GPP. Embodiments of the invention can be adapted to the 4G radio
communication system by way of examples, so an overview of the 4G radio
communication system will be described.
[0034]
15 [ 1 -1. Configuration of radio communication system]
FIG. 1 is an explanatory diagram showing an example of a configuration of
a radio communication system 1. As shown in FIG. 1, the radio communication
system 1 includes a base station 10, a core network including an MME (Mobility
Management Entity) 12, an S-GW (Serving Gateway) 14, and a PDN (Packet Data
20 Network)-GW 16, MTC terminals 20, and an MTC server 30.
[0035]
Embodiments of the invention can be adapted to radio communication
devices such as the base station 10 and the MTC terminals 20 shown in FIG. 1.
Notably, the base station 10 may for example be an eNodeB, a relay node, or a Home
25 eNodeB that is a compact base station for home, use. Further, the MTC terminals 20
are examples of user equipment (UE), and adaptations to non-MTC terminals such as
a cell phone, PC (Personal Computer), and the like is also possible as embodiments
of the invention.
[0036]
30 The base station 10 is a radio base station that communicates with the MTC
terminals 20. Although only one base station 10 is shown in FIG. 1, a large number
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of base stations 10 are connected to the core network in reality. Further, although
depiction in FIG. 1 is omitted, the base station 10 communicates also with other user
equipments such as a non-MTC terminal.
[0037]
5 The MME 12 is a device that performs controls of settings, opening, and
hand-over of a data conmiunication session. The MME 12 is connected to the base
station 10 via an interface called X2.
[0038]
The S-GW 14 is a device that performs routing and transfer of user data.
10 The PDN-GW 16 functions as a connecting node with an IP service network, and
transfers the user data to and from the IP service network.
[0039]
The MTC terminals 20 are radio terminals specialized for MTC, which is a
communication between machines and is not used directly by a human, which is
15 under discussion in the 3GPP. The MTC terminals 20 perform radio
communication in accordance with an application with the base station 10. Further,
the MTC terminals 20 perform bidirectional communication with the MTC server 30
via the core network.
[0040]
20 For example, as a medical application of the MTC, a case may be assumed
in which an MTC terminal 20 collects electrocardiogram information of a human,
and transmits the electrocardiogram information to the server by using uplink when a
certain trigger condition is met. As another application of the MTC, a case may be
assumed in which a vending machine is caused to function as the MTC terminal 20,
25 and the MTC server 30 causes the vending machine under management to report
sales once every certain cycle (for example, every 30 days).
[0041]
Such an MTC terminal 20 by way of example has the following features in
general, however, not every MTC terminal 20 needs to have all of the following
30 features, and which of the features is to be assigned depends on applications.
Scarce needs to move (Low Mobility)
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Transmission of small data (Online Small Data Transmission)
Very low power consumption (Extra Low Power Consumption)
Handled by grouping respective MTCs (Group-based MTC Features)
[0042]
5 [ 1 -2. Configuration of frame]
Although details of the aforementioned base station 10 and MTC terminals
20 are not decided, they are expected to perform radio communication conforming to
communication between the eNodeB and the UE. Thus, hereinbelow, a radio frame
shared between the eNodeB and the UE will be described. Contents to be described
10 hereinbelow can be applied to the communication between the base station 10 and
the MTC terminals 20.
[0043]
FIG. 2 is an explanatory diagram showing a 4G frame format. As shown in
FIG. 2, a 10ms radio frame is configured often 1ms sub frames #0 to #9. Further,
15 each 1ms sub frame is configured of two 0.5 ms slots. Further, each 0.5 ms slot is
configured of seven Ofdm symbols.
[0044]
Notably, the Ofdm symbol is a unit used in a communication scheme of an
OFDM (Orthogonal Frequency Division Multiplexing) modulation system, and is a
20 unit by which data processed in one FFT (Fast Fourier Transform) is outputted.
[0045]
At a head of each 1ms sub frame shown in FIG. 2, a control signal called a
PDCCH (Phy Downlink Control Channel) is added. As shown in FIG. 3A to FIG.
3C, one Ofdm symbol to three Ofdm symbols at the head of the sub frame are used
25 for a transmission of the PDCCH. That is, there are cases in which one Ofdm
symbol is used for the PDCCH transmission, and there also are cases in which three
Ofdm symbols are used for the PDCCH transmission.
[0046]
Notably, a region in the radio frame used for the PDCCH transmission is
30 called a control region, and a region in the radio frame used for transmissions of a
PDSCH (Phy Downlink Shared Channel) or a PUSCH (Phy Uplink Shared Channel)
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is called a data region.
[0047]
[1-3. Configuration of PDCCH]
Next, control information included in the PDCCH will be described.
5 Although various types of control information are included in the PDCCH, the
following two pieces of control information are primarily included.
(1) Assigning information indicating a resource block that the UE is to receive from
among the PDSCH (assign)
(2) Granting information indicating a resource block that the UE is to transmit from
10 among the PUSCH (grant)
[0048]
Notably, as shown in FIG. 4, a minimum unit of the resource block is twelve
subcarriers x seven Ofdm symbols. Further, other than the resource information for
example of assign, grant, and the like, the PDCCH further includes power control
15 information, paging indexes, system information and the like.
[0049]
[1-4. Blind decoding]
The resource information such as assign and grant as above are information
for each UE. Due to this, the eNodeB transmits the PDCCH so that each UE can
20 extract the resource information addressed to itself, and each UE extracts the
resource information addressed to itself from the PDCCH by a process called blind
decoding. Hereinbelow, this feature will be described in detail.
[0050]
In the PDCCH, the minimum unit of the control information for each UE is
25 called CCE (Control Channel Element). The eNodeB includes the resource
information for each UE, and generates CCEs identified by a C-RNTI (Cell Radio
Network Temporary Identify) that is an identifier of each UE. Hereinbelow,
specific examples of the CCE will be described with reference to FIG. 5.
[0051]
30 FIG. 5 is an explanatory diagram showing a specific example of the CCE.
As shown in FIG. 5, the CCE includes target information such as the resource
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information, as well as a check bit that is obtained by a CRC (Cyclic Redundancy
Check) by masking the resource information with the C-RNTI (Cell Radio Network
Temporary Identify). Here, the masking may be an exclusive disjunction
calculation (XOR) of the resource information and the C-RNTI, or may be a serial
5 coupling of the resource information and the C-RNTI.
[0052]
When the PDCCH including the aforementioned plurality of CCEs is
received, the UE extracts the CCE identified by its own C-RNTI by the blind
decoding. Hereinbelow, a more specific description will be given with reference to
10 FIG. 6 and FIG. 7.
[0053]
FIG. 6 and FIG. 7 are explanatory diagrams showing the blind decoding.
As shown in FIG. 6, as the blind decoding, the UE performs CRC check by
demasking each CCE with its own C-RNTI. Further, the UE performs the blind
15 decoding on each CCE in an order shown in FIG. 7. That is, the UE performs the
CRC check of each CCE on an assumption that each CCE is addressed to itself, and
determines the CCE with a normal result as the CCE addressed to itself.
[0054]
(CCE aggregation)
20 Notably, in connection to the aforementioned CCEs, there is a concept
called CCE aggregation. The CCE aggregation is a mode in which CCEs are
transmitted at an amount that is one, two, four, or eight times the typical unit of the
CCE.
[0055]
25 For example, in a cell with a large cell radius, when an SN (signal to noise
ratio) of a UE can be predicted to be small, the CCEs are transmitted by being
repeated eight times. In this case, the check bit by the CRC is added to the result of
the eight times of repetition. Accordingly, the UE performs the blind decoding by
taking into account a possibility that the CCE aggregation has been performed.
30 [0056]
Further, other than the C-RNTI, RNTIs such as a P-RNTI for acquiring
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information for paging and an SI-RNTI for acquiring system information exist.
Accordingly, the UE performs the blind decoding by assuming by which of the
RNTIs each of the CCEs is to be identified.
[0057]
5 (Particulars of achieving the embodiments of the invention)
Incidentally, in the 4G radio communication system, due to the introduction
of the aforementioned MTC terminals, increases are expected in a number of
terminals existing within each cell, a number of terminals the base station is to
contain in an Active mode, and a number of terminals for the base station 10 to
10 simultaneously control in the PDCCH. Further, the CCE included in the PDCCH
also increases accompanying the increase in the number of terminals simultaneously
controlled in the PDCCH.
[0058]
As a result, load of the blind decoding in the UE increases due to a range
15 requiring the blind decoding by the UE (including the MTC terminal) being broader.
Especially, there are cases in which the extra-low power consumption is required in
the MTC terminal, so the increase in the load of the blind decoding is problematic.
[0059]
Thus, the embodiments of the invention have been created with the above
20 circumstance as a point of concern. According to the embodiments of the invention,
load of the blind decoding in the MTC terminal 20 can be suppressed. Hereinbelow,
such embodiments of the invention will be described in detail.
[0060]
<2. Description of Respective Embodiments>
25 As described in detail in "2-1. First embodiment" to "2-7. Seventh
embodiment" by way of example, the invention can be implemented in various
manners. Further, each embodiment is implemented by using an MTC-GP_RNTI
which is an identifier of an MTC group assigned to the MTC terminal 20. Thus,
prior to the detailed description of the respective embodiments, a method of
30 assigning the MTC-GP_RNTI to each MTC terminal 20 will be described.
[0061]
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(Assigning MTC-GP__RNTI)
FIG. 8 is a sequence diagram showing an example of a method of assigning
C-RNTI and MTC-GP_RNTI. As shown in FIG. 8, firstly, in a random access
procedure formed of Step 1 to Step 4, the C-RNTIs are assigned to each MTC
5 terminal 20.
[0062]
More specifically described, the MTC terminal 20 transmits a preamble to a
random access window in a radio frame (Step 1). In successfully receiving the
preamble from the MTC terminal 20, the base station 10 transmits a random access
10 response to the MTC terminal 20 (Step 2). The base station 10 assigns a Temporary
C-RNTI to the MTC terminal 20 in this random access response.
[0063]
Then, when the random access response is received, the MTC terminal 20
transmits an L2/L3 message to the base station 10 (Step 3). In connection to the
15 above, the MTC terminal 20 determines that a random access had been successful by
receiving a contention resolution message transmitted from the base station 10 (Step
4), and begins using the Temporary C-RNTI assigned in Step 2 as the C-RNTI.
[0064]
Thereafter, an MTC category setting procedure formed of Step 5 and Step 6
20 is performed. More specifically described, since the MTC terminal 20 is set with
information of an MTC category indicating whether the MTC terminal 20 itself is an
MTC terminal or not, the MTC terminal 20 is aware that itself is an MTC terminal.
Due to this, the MTC terminal 20 notifies the base station 10 of the MTC category
(Step 5), and receives a notification confirming signal from the base station 10 (Step
25 6). Notably, the MTC category may include information indicating a capacity of
the MTC terminal 20, such as whether the MTC terminal 20 is compliant with a long
sleep mode for over one month or not.
[0065]
Further, in an MTC-GP_RNTI setting procedure formed of Step 7 and Step
30 8, the MTC-GP_RNT1 is assigned to the MTC terminal 20. More specifically
described, the MTC terminal 20 performs an MTC group setting request to the base
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station 10 (Step 7). The base station 10 transfers the aforementioned setting request
to the MME 12 together with a terminal ID of the MTC terminal 20 (a unique
number described, in an SIM, and is different from the RNTI).
[0066]
5 The MME 12 is a device that handles the unique information of the
terminals, receives correspondence information of an MTC group and the terminal
IDs of the terminals that are granted to enter the MTC group from the MTC server 30,
and retains the correspondence information. The MME 12 determines whether an
MTC terminal 20 having the terminal ID transferred from the base station 10 is
10 allowed to enter the MTC group or not based on the correspondence information, and
if the MTC terminal 20 is allowed to enter, the MME 12 transmits an MTC group
setting confirming signal to the base station 10.
[0067]
Subsequently, the base station 10 transmits the MTC-GP_RNTI to the MTC
15 terminal 20 together with the MTC group setting confirming signal (Step 8). Then,
the MTC terminal 20 becomes capable of using the MTC-GP_RNTI by receiving the
MTC group setting confirming signal and the MTC-GP_RNTI from the base station
10.
[0068]
20 The method of assigning the MTC-GP_RNTI is described above, however,
the method of assigning the MTC-GP_RNTI is not limited to the above example.
For example, information such as an AC (Access Class) that is predeterminedly set in
the MTC terminal 20 may be used as the MTC-GP_RNTI, and the MTC-GP_RNTI
may be assigned to the MTC terminal 20 by a human operation.
25 [0069]
[2-1. First embodiment]
Next, the first embodiment of the invention will be described with reference
to FIG. 9 to FIG. 13.
[0070]
30 (Base station of first embodiment)
FIG. 9 is an explanatory diagram showing a configuration of a base station
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10 of the first embodiment of the invention. As shown in FIG. 9, the base station 10
of the first embodiment includes an antenna 104, a radio processing section 108, a
storage section 112, a scheduler 116, a control signal generating section 120, a CRC
circuit 124, and a data mapping section 128.
5 [0071]
The antenna 104 functions as a transmitter section that transmits a
transmitter signal such as a PDCCH (control signal) and a PDSCH (data signal)
supplied from the radio processing section 108 as a radio signal, and as a receiver
section that converts the radio signal transmitted from a radio communication device
10 such as an MTC terminal 20 into an electric receiver signal, and supplies the receiver
signal to the radio processing section 108. Notably, in FIG. 9, although an example
in which the base station 10 includes one antenna is shown, the base station 10 may
include a plurality of antennas. In this case, the base station 10 is capable of
realizing an MIMO (Multiple Input, Multiple Output) communication, a diversity
15 communication and the like.
[0072]
The radio processing section 108 performs radio processes for transmission
such as modulation, DA conversion, filtering, amplification, and up-conversion of
the transmitter signal such as the PDCCH supplied from the control signal generating
20 section 120, the PDSCH supplied from the data mapping section, and the like.
Further, the radio processing section 108 performs radio processes for reception such
as down-conversion, filtering, DA conversion, and demodulation of the receiver
signal supplied from the antenna 104.
[0073]
25 The storage section 112 stores the MTC-GP_RNTIs, the C-RNTIs and the
like that are assigned to the respective MTC terminals 20. Further, although
depiction is omitted in FIG. 9, the storage section 112 also stores other RNTIs such
as SI-RNTIs, P-RNTIs, and RA-RNTIs.
[0074]
30 The scheduler 116 allots a resource to each MTC terminal 20 for data
communication. That is, the scheduler 116 allots resource blocks among the
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PDSCH that the respective MTC terminals 20 are to receive, and resource blocks
among the PUSCH that the respective MTC terminals 20 are to transmit.
[0075]
The control signal generating section 120 generates a PDCCH formed of a
5 plurality of CCEs. To describe in further detail, the control signal generating
section 120 generates a CCE including information indicating a second search space
arranged within data region (reference information) and a check bit obtained by the
CRC circuit 124 by masking the aforesaid information by the MTC-GP_RNTI.
Here, the masking may be an exclusive disjunction calculation (XOR) of the
10 information indicating the second search space and the MTC-GP_RNTI, or may be a
serial coupling of the information indicating the second search space and the C-RNTI.
According to the above configuration, an MTC terminal 20 within an MTC group to
which the MTC-GP_RNTI is assigned can be designated as a destination of the
information indicating the second search space.
15 [0076]
Notably, although an example in which the check bit corresponding to the
information indicating the second search space is added to designate the destination
of the CCE is described above, a method of designating the destination of the CCE is
not limited to the above example. For example, the control signal generating
20 section 120 may designate the designation of the CCE simply by attaching the MTCGPRNTI
to the information indicating the second search space.
[0077]
Further, the control signal generating section 120 generates information for
mapping in the second search space, and supplies the same to the data mapping
25 section 128 together with information indicating a position of the second search
space. Here, the information for mapping in the second search space is the resource
information for the respective MTC terminals 20 within the MTC group to which the
MTC-GPRNTI is assigned. Further, a check bit obtained by the CRC circuit 124
by masking the aforesaid information with the C-RNTIs of the respective MTC
30 terminals 20 is added to the resource information for the respective MTC terminals.
20. *
SP308569WO00
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[0078]
The data mapping section 128 (data signal generating section) maps user
data for each MTC terminal 20 supplied from an upper layer in the resource block
allotted by the scheduler 116 among the PDSCH that the respective MTC terminals
5 20 are to receive. Further, the data mapping section 128 maps the resource
information of the respective MTC terminals 20 supplied from the control signal
generating section 120 in the second search space. Hereinbelow, a disposition
relationship of the CCE, the second search space, the allotted resource and the like
will be described more specifically with reference to FIG. 10.
10 [0079]
FIG. 10 is an explanatory diagram showing the disposition relationship of
the CCE, the second search space, and the allotted resource. In the example shown
in FIG. 10, a CCE #1 describes information indicating a position of a second search
space #1 for an MTC group having an MTC-GP_RNTI corresponding to a check bit
15 added to the CCE #1.
[0080]
Then, among a plurality of resource information included in the second
search space #1, for example, resource information #1 indicates a resource block #1
for the MTC terminal 20 having a C-RNTI corresponding to a check bit added to the
20 resource information #1. Further, the resource information #2 indicates a resource
block #2 for the MTC terminal 20 having a C-RNTI corresponding to a check bit
added to the resource information #2;
[0081]
Similarly, a CCE #2 shown in FIG. 10 describes information indicating a
25 position of a second search space #2 for an MTC group having an MTC-GP_RNTI
corresponding to a check bit added to the CCE #2. Further, of a plurality of
resource information included in the second search space #2, for example, resource
information #3 indicates a resource block #3 for the MTC terminal 20 having a CRNTI
corresponding to a check bit added to the resource information #3.
30 [0082]
Notably, the CCE and the second search space may be disposed in the same
SP308569WO00
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sub frame as with the CCE #1 and the second search space #1, or may be disposed in
different sub frames as with the CCE #2 and the second search space #2. Such a
relationship of the CCE and the second search space may fixedly be set by signaling
in advance, or may be designated by the CCE.
5 [0083]
Further, since processing cannot be performed trniely if the resource blocks
indicated by the respective resource information included in the second search space
are in the same sub frame as the second search space, the resource blocks are
disposed in a sub frame that is after the sub frame of the second search space, such as
10 with the resource block #1 and the resource block #2. Such a relationship of the
second search space and the allotted resource blocks of the respective MTC terminals
20 may fixedly be set by signaling in advance, or may be designated by the second
search space.
[0084]
15 (MTC terminal of first embodiment)
Hereabove, the configuration of the base station 10 of the first embodiment
of the invention was described. Now, a configuration of the MTC terminal 20 of
the first embodiment of the invention will be described.
[0085]
20 FIG. 11 is an explanatory diagram showing the configuration of the MTC
terminal 20 of the first embodiment. As shovra in FIG. 11, the MTC terminal 20 of
the first embodiment includes an antenna 204, a radio processing section 208, a
storage section 212, a blind decoding section 220, and a CRC circuit 224.
[0086]
25 The antenna 204 fiinctions as a transmitter section that transmits a
transmitter signal such as a PUSCH(data signal) supplied from the radio processing
section 208 as a radio signal, and as a receiver section that converts the radio signal
such as the PDCCH and the PDSCH transmitted from a base station 10 into an
electric receiver signal, and supplies the receiver signal to the radio processing
30 section 208. Notably, in FIG. 11, although an example in which the MTC terminal
20 includes one antenna is shown, the MTC terminal 20 may include a plurality of
SP308569WO00
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antennas. In this case, the MTC terminal 20 is capable of realizing an MIMO
(Multiple Input, Multiple Output) communication, a diversity communication and the
like.
[0087]
5 The radio processing section 208 performs radio processes for transmission
such as modulation, DA conversion, filtering, amplification, and up-conversion of
user data supplied from an upper layer. Further, the radio processing section 208
performs radio processes for reception such as down-conversion, filtering, DA
conversion, and demodulation of the receiver signal supplied from the antenna 104.
10 [0088]
The storage section 212 stores for example the MTC-GP_RNTIs, the CRNTIs
and the like that are assigned from the base station 10. Further, although
depiction is omitted in FIG. 11, the storage section 212 also stores other RNTIs such
as SI-RNTI, P-RNTI, and RA-RNTI.
15 [0089]
When the PDCCH is supplied from the radio processing section 208, the
blind decoding section 220 (acquiring section) extracts the CCE identified by the
MTC-GP_RNTI assigned to the MTC terminal 20 by the blind decoding. More
specifically described, the blind decoding section 220 operates in cooperation with
20 the CRC circuit 224 to perform CRC check by demasking each CCE by the MTCGPRNTI
assigned to the MTC terminal 20. Then, the blind decoding section 220
extracts the CCE with a normal result, and specifies the second search space based
on the information described in the CCE. For example, the blind decoding section
220 extracts the CCE #1 shown in FIG. 10 from the PDCCH, and specifies the
25 second search space #1 based on the information described in the CCE #1.
[0090]
Further, when the PDSCH is supplied from the radio processing section 208,
the blind decoding section 220 acquires the resource information addressed to itself
by performing the blind decoding using the C-RNTI on the second search space
30 specified from the CCE. More specifically, the blind decoding section 220 operates
in cooperation with the CRC circuit 224 to perform CRC check by demasking each
SP308569WO00
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resource information in the second search space using the C-RNTI. Then, the blind
decoding section 220 acquires the resource information with a normal result as the
resource information addressed to itself Thereafter, the radio processing section
208 performs the transmission process or the reception process in the resource block
5 indicated by the resource information. For example, the blind decoding section 220
acquires the resource information #1 in the second search space #1 shown in FIG. 10
as the resource information addressed to itself. Thereafter, the radio processing
section 208 performs the reception process in the resource block #1 indicated by the
resource information #1.
10 [0091]
As described above, according to the first embodiment of the invention, by
mapping the resource information (assign, grant) for each MTC terminal 20 in the
second search space in the PDSCH, the resource information for a large number of
MTC terminals 20 can be contained. Further, since a number of the CCEs in the
15 PDCCH can be suppressed, the search space in which the MTC terminal 20 performs
the blind decoding can be reduced. As a result, load related to the blind decoding in
the MTC terminal 20 can be reduced. Notably, although an example in which the
resource information for the respective MTC terminals 20 are mapped in the second
search space was described above, the first embodiment is not limited to this
20 example. For example, communication controlling information for each MTC
terminal 20 such as transmission power and transmission rate, and other various
types of information for each MTC terminal 20 may be mapped in the second search
space.
[0092]
25 (Operation of first embodiment)
Hereabove, the configuration of the MTC terminal 20 of the first
embodiment of the invention was described. Next, an operation of the radio
communication system 1 of the first embodiment of the invention will be described.
[0093]
30 FIG. 12 is a sequence diagram showing the operation of the radio'
communication system 1 of the first embodiment of the invention. The base station
SP308569WO00
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10 firstly decides a second search space for one MTC group (S310). Then, the
control signal generating section 120 of the base station 10 describes information
indicating the decided second search space in the CCE in the PDCCH in a state
capable of being identified by MTC-GP_RNTI assigned to the MTC group (S320).
5 More specifically, the control signal generating section 120 adds a check bit obtained
by the CRC circuit 124 by masking the information indicating the second search
space with the MTC-GP_RNTI to the CCEs.
[0094]
Further, the data mapping section 128 of the base station 10 maps the
10 resource information for each MTC terminal 20 belonging to the MTC group in the
second search space of the PDSCH in a state capable of being identified by C-RNTI
assigned to each MTC terminal 20 (S330). Thereafter, the base station 10 transmits
the PDCCH and the PDSCH (S340).
[0095]
15 Then, when the MTC terminal 20 receives the PDCCH from the base station
10, the blind decoding section 220 of the MTC terminal 20 performs the blind
decoding on the respective CCEs in the PDCCH using the MTC-GP_RNTI assigned
to itself (S350), and specifies the second search space for the MTC group including
the terminal itself (S3 60).
20 [0096]
Further, when the MTC terminal 20 receives the PDSCH from the base
station 10, the blind decoding section 220 of the MTC terminal 20 performsthe blind
decoding on the second search space in the PDSCH using the C-RNTI (S370), and
acquires the resource information for the terminal itself (S3 80). Thereafter, the
25 MTC terminal 20 performs the reception process or the transmission process in the
resource block indicated by the acquired resource information.
[0097]
(Supplementation of first embodiment)
As described above, the base station 10 of the first embodiment of the
30 invention transmits the PDCCH by describing the information indicating the second
search space in the CCEs in the state capable of being identified by the MTCSP308569WO00
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GP_RNTI. However, a case in which the base station 10 transmits the PDCCH by
describing the resource information for the MTC terminal 20 in the CCEs in a state
capable of being identified by the C-RNTI of the MTC terminal 20 may also be
possible.
5 [0098]
Thus, the MTC terminal 20 may perform the blind decoding of the PDCCH
by using both the MTC-GP_RNTI and the C-RNTI. Even in the case of performing
the blind decoding of the PDCCH by using both the MTC-GP_RNTI and the CRNTI,
since the search space is made small according to the first embodiment of the
10 invention, load on the MTC terminal 20 can be suppressed sufficiently.
[0099]
Alternatively, in a case where it is determined that the base station 10 cannot
handle the MTC-GP_RNTI, the MTC terminal 20 may perform the blind decoding
by using only the C-RNTI. Notably, as the case in which the base station 10 cannot
15 handle the MTC-GP_RNTI, a case in which the MTC terminal 20 is connected to a
new base station 10 by a hand-over, or a case in which the base station 10 does not
have a capability to handle the MTC-GP_RNTI is expected.
[0100]
Alternatively, as will be described with reference to FIG. 13, the MTC
20 terminal 20 may change the RNTI to be used in the blind decoding by requesting a
setting change to the base station 10.
[0101]
FIG. 13 is a sequence diagram showing an example of a method of changing
the RNTI used for the blind decoding. As shovra in FIG 13, in the case where the
25 MTC terminal 20 performs the blind decoding of the PDCCH by using both the
MTC-GP_RNTI and the C-RNTI, a setting request of MTC-GP_Only_Mod can be
transmitted to the base station 10 (S410).
[0102]
When the setting request is received, the base station 10 sets the MTC-
30 GP_Only_Mod that describes the information indicating at least the second search
space for the MTC group to which the MTC terminal 20 belongs in the CCE in a
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state capable of being identified by the MTC-GP_RNTI. Then, the base station 10
transmits a setting confirming signal of the MTC-GP_Only_Mod to the MTC
terminal 20 (S420). Notably, the base station 10 may transmit the setting
confirming signal of the MTC-GP_Only_Mod to all of the MTC terminals belonging
5 to the MTC group.
[0103]
After receiving the setting confirming signal of the MTC-GP_Only_Mod,
the MTC terminal 20 performs the blind decoding by using only the MTC-GP_RNTI.
[0104]
10 Thereafter, when the MTC terminal 20 transmits a release request of the
MTC-GP_Only_Mod to the base station 10, (S430), the base station 10 releases the
setting of the MTC-GP_Only_Mod, and transmits a release confirming signal of the
MTC-GP_Only_Mod to the MTC terminal 20 (S440). After having received the
release confirming signal of the MTC-GP_Only_Mod, the MTC terminal 20 again
15 performs the blind decoding of the PDCCH using both the MTC-GP_RNTI and the
C-RNTI.
[0105]
[2-2. Second embodiment]
Hereabove, the first embodiment of the invention was described. Now, a
20 second embodiment of the invention will be described. Notably, since the second
embodiment to the seventh embodiment described below have a large number of
portions in common with the first embodiment, detailed descriptions for the portions
in common with the first embodiment will be omitted. Further, the second
embodiment to the seventh embodiment will be described by reusing the
25 configurational diagram of the base station 10 shovm in FIG 9 and the
configurational diagram of the MTC terminal 20 shown in FIG. 11.
[0106]
FIG. 14 is an explanatory diagram showing an example of disposition of the
second search space for a certain MTC group. As shown in FIG. 14, a base station
30 10 may dispose second search spaces #1 to #3 at a same position that one CCE #1
indicates over a plurality of sub frames.
SP308569WO00
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[0107]
In this case, an MTC terminal 20 needs to know over how many sub frames
the second search spaces are to be disposed at the same position. Due to this, the
base station 10 may notify a number of the sub frames in CCE, or may notify the
5 number of the sub frames to the MTC terminal 20 in advance.
[0108] -
According to this second embodiment, since the number of the CCEs in
PDCCH can further be reduced, load related to blind decoding on the MTC terminal
20 can further be reduced.
10 [0109]
[2-3. Third embodiment]
As described with reference to FIG. 7, typically, after searching CCE in
PDCCH in a frequency direction, an MTC terminal 20 searches the following Ofdm
symbol again in the frequency direction. Due to this, in an LTE, a search in the
15 frequency direction with a minimum width of 5 MHz and a maximum width of 20
MHz is required.
[0110]
However, from viewpoints that the MTC terminal 20 in some cases is
required to have an extra low power consumption, and of an operation efficiency of a
20 digital circuit, it is effective to make the search width in the frequency direction be 5
MHz or less, for example, 1 MHz or less.
[0111]
Thus, the base station 10 of the third embodiment disposes the CCEs for the
same MTC group in a predetermined sub carrier. Hereinbelow, specific
25 descriptions will be given with reference to FIG. 15.
[0112]
FIG. 15 is an explanatory diagram showing an example of disposition of the
CCEs for each MTC group. As shown in FIG. 15, the base station 10 of the third
embodiment for example disposes CCE for an MTC terminal 20 belonging to an
30 MTC group 1 in a sub carrier x, and disposes CCE for an MTC terminal 20
belonging to an MTC group 2 in a sub carrier y. Notably, the base station 10 may
SP308569WO00
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notify the MTC terminals 20 in advance of information indicating which sub carrier
the CCE for each MTC group is going to be disposed in.
[0113]
According to the above configuration, the MTC terminal 20 belonging to
5 the MTC group 1 can shnply perform the blind decoding only on the sub carrier x in
a time direction, and the MTC terminal 20 belonging to the MTC group 2 can simply
perform the blind decoding only on the sub carrier y in the time direction. Thus,
according to the third embodiment, load related to the blind decoding in the MTC
terminal 20 can significantly be reduced.
10 [0114]
[2-4. Fourth embodiment]
In the above embodiment, an example in which the MTC terminals 20
belong to one MTC group and one MTC-GP_RNTI is assigned was described. On
the other hand, a case in which the MTC terminals 20 are grouped separately for
15 uplink and downlink is also expected. The fourth embodiment focuses on this
feature, and MTC terminals 20 of the fourth embodiment belong to a plurality of
MTC groups, and a plurality of MTC-GP_RNTIs are assigned. Hereinbelow, a
specific example will be described with reference to FIG. 16.
[0115]
20 FIG. 16 is an explanatory diagram showing a specific example of an MTC
group to which MTC terminals 20 belong. As shown in FIG. 16, the MTC
terminals 20 of the fourth embodiment belong to- an uplink MTC group and a
downlink MTC group. For example, an MTC terminal 20A belongs to a downlink
MTC group 1 and an uplink MTC group 1, and an MTC terminal 20B belongs to the
25 downlink MTC group 1 and an uplink MTC group 3.
[0116]
Due to this, MTC-DownLink_RNTI that is a downlink group identifier and
MTC-UpLink_RI>>[TI that is an uplink group identifier are assigned to each MTC
terminal 20.
30 [0117]
In this case, a base station 10 generates the CCE including information
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indicating a second search space for the uplink by using the MTC-UpLink;_RNTI,
and generates the CCE including information indicating a second search space for
the downlink by using the MTC-DownLink_RNTI.
[0118]
5 ' For example, in a case of describing the information indicating the second
search space for the uplink MTC group 1 in the CCE #4 shown in FIG. 17, the base
station 10 generates the CCE #4 by using the MTC-UpLink_RNTI assigned to the
uplink MTC group 1. Similarly, in a case of describing the information indicating
the second search space for the downlink MTC group 2 in the CCE #5 shown in FIG.
10 17, the base station 10 generates the CCE #5 by using the MTC-DownLink_RNTI
assigned to the downlink MTC group 2.
[0119]
Due to this, the MTC terminal 20 can extract the CCE for the MTC group to
which the MTC terminal 20 belongs by performing blind decoding on each CCE in
15 the PDCCH by using the MTC-DownLink_RNTI and the MTC-UpLink_RNTI.
[0120]
[2-5. Fifth embodiment]
As described above, the first embodiment to the fourth embodiment make
the search space in the PDCCH small by using the second search space. With
20 respect to this, the fifth embodiment to the seventh embodiment described below
make the search space in the PDCCH small by describing the resource information
shared by a plurality of MTC terminals 20 configuring an MTC group in the CCE.
Hereinbelow, the fifth embodiment to the seventh embodiment will orderly be
described.
25 [0121]
(Sharing downlink resource information)
As applications of an MTC terminal 20, applications for reporting
accumulated information such as reporting sales performance of a vending machine,
reporting used amount of gas or water are primarily expected. In such cases, a base
30 station 10 can use a common command for instructing a plurality of MTC terminals
20 to report the accumulated information.
SP308569WO00
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[0122]
Thus, the base station 10 describes resource information indicating a
resource block to which the plurality of MTC terminals 20 in an MTC group is to
perform a reception process in the CCE. Further, the base station 10 transmits the
5 CCE in a state capable of being identified by MTC-GP_KNTI by adding a check bit
based on the MTC-GP_RNTI assigned to the MTC group to the CCEs.
[0123]
Then, the plurality of MTC terminals 20 in the MTC group performs blind
decoding using the MTC-GP_RNTI, and extracts the CCE identified by the MTC-
10 GP_RNTI. Further, the plurality of MTC terminals 20 in the MTC group
simultaneously performs the reception process in the resource block indicated by the
resource information described in the extracted CCE.
[0124]
According to the above configuration, since the resource information to the
15 respective MTC terminals 20 does not need to be described in different CCEs, the
search space in the PDCCH can further be made smaller.
[0125]
(Sharing uplink resource information)
In an uplink, if the plurality of MTC terminals 20 performs a transmission
20 process in the same resource block, uplink data collapses at the base station 10.
Thus, the base station 10 describes resource information indicating a reference
resource block for the uplink of the MTC group in the CCE. Further, the base
station 10 transmits the CCE in a state capable of being identified by MTCGP_
RNTI by adding a check bit based on the MTC-GP_RNTI assigned to the MTC
25 group to the CCEs.
[0126]
Then, the plurality of MTC terminals 20 in the MTC group performs blind
decoding using the MTC-GP_RNTI, and extracts the CCE identified by the MTCGP_
RNTI. Further, the plurality of MTC terminals 20 in the MTC group specifies
30 the reference resource block indicated by the resource information described in the
extracted CCE, and performs the transmission process in the resource block that is in
SP308569WO00
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a positional relationship with the reference resource block as set in advance.
Hereinbelow, this feature will be described more specifically with reference to FIG.
18.
[0127]
5 FIG. 18 is an explanatory diagram showing a relationship of a reference
resource block and an uplink resource block of each MTC terminal 20. As shown
in FIG. 18, for example, resource information indicating a resource block #1 as the
reference resource block of the uplink of a MTC group 1 is described in CCE #6.
[0128]
10 Here, it is assumed that the MTC group 1 is configured of MTC terminals
20A to 20D, and a relative position of a resource block to be used for the uplink by
each MTC terminal 20 from the reference resource block is set. In this case, the
MTC terminals 20A to 20D specify the resource block #1 that is the reference
resource block, and perform the transmission process by using the resource block
15 that is at the set relative position from the reference resource block.
[0129]
For example, a case of a setting in which the reference resource block is an
origin, and resource blocks that are adjacent in a time direction are used in an order
of the MTC terminals 20A, 20B, 20C, and 20D will be assumed. In this case, as
20 shown in FIG. 18, the MTC terminal 20A uses the resource block #1 that is the
reference resource block, the MTC terminal 20B uses a resource block #2 that is
adjacent with the resource block #1 in the time direction. Similarly, the MTC
terminal 20C uses a resource block #3 that is adjacent with the resource block #2 in
the time direction, and the MTC terminal 20D uses a resource block #4 that is
25 adjacent with the resource block #3 in the time direction.
[0130]
As a modification, settings may be made with a reference resource block as
an origin to use resource blocks that are adjacent in a frequency direction in an order
of MTC terminals 20A, 20B, 20C, and 20D. In this case, as shown in FIG. 19, the
30 MTC terminal 20A uses a resource block #1 that is the reference resource block, and
the MTC terminal 20B uses the resource block #5 that is adjacent to the resource
SP308569WO00
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block #1 in the frequency direction. Similarly, the MTC terminal 20C uses the
resource block #6 that is adjacent to the resource block #5 in the frequency direction,
and the MTC terminal 20D uses the resource block #7 that is adjacent to the resource
block #6 in the frequency direction.
5 [0131]
Notably, the base station 10 may signal the positional relationship of the
resource block to which each MTC terminal 20 is to perform the transmission
process and the reference resource block in advance to each MTC terminal 20.
Further, although an example in which the fifth embodiment is implemented by the
10 MTC-GP_R]SrTI was described, the fifth embodiment may be implemented by
replacing the MTC-GP_RNTI with the C-RNTI. For example, in a case of not
being able to handle the MTC-GP_RNTI, the base station 10 can allot the same CRNTI
to a plurality of MTC terminals 20, and the C-RNTI may be used in a similar
way as with the above MTC-GP_RNTI.
15 [0132]
(Operation of fifth embodiment)
Hereabove, sharing of the resource information in the fifth embodiment was
described. Now, an operation of the radio communication system 1 according to the
fifth embodiment will be described with reference to FIG. 20.
20 [0133]
FIG. 20 is an explanatory diagram showing the operation of the radio
communication system 1 of the fifth embodiment. As shown in FIG. 20, the base
station 10 transmits relative position information indicating the positional
relationship of the resource blocks to which the MTC terminals 20 are to perform the
25 transmission to the MTC terminals 20 in advance (S510).
[0134]
Thereafter, the control signal generating section 120 of the base station 10
describes the resource information for each MTC terminal 20 belonging to the MTC
group in a state capable of being identified by the MTC-GP_RNTI assigned to the
30 MTC group to the CCEs in the PDCCH (S520). Specifically, the control signal
generating section 120 adds the check bit obtained by the CRC circuit 124 by
SP308569WO00
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masking the resource information for each MTC terminal 20 with the MTCGP_
RNTI to the CCEs. Then, the base station 10 transmits the PDCCH including
the CCE in which the resource information for each MTC terminal 20 is described
(S530).
5 [0135]
Then, when each MTC terminal 20 receives the PDCCH from the base
station 10, the blind decoding section 220 of the MTC terminal 20 performs blind
decoding on each CCE in the PDCCH by using the MTC-GP_RNTI assigned to itself
(S540), and obtains the resource information for the MTC group including itself
10 (S550).
[0136]
Here, in a case where the obtained resource information indicates a
downlink resource block (S560), the MTC terminal 20 performs the reception
process in the resource block indicated by the resource information (S 570).
15 [0137]
On the other hand, in a case where the obtained resource information
indicates an uplink resource block (S560), the MTC terminal 20 performs the
transmission process in the resource block that is in the positional relationship as
indicated by the relative position information with the reference resource block
20 indicated by the resource information (S 580).
[0138]
As described above, according to the fifth embodiment, due to no longer
being necessary to describe the resource information for each MTC terminal 20 to
the respective CCEs, the search space in the PDCCH can be made small. As a
25 result, load related to the blind decoding in the MTC terminals 20 can be reduced.
[0139]
[2-6. Sixth embodiment]
The sixth embodiment is implemented by adapting the third embodiment
described with reference to FIG. 15 to the fifth embodiment. Specifically, a base
30 station 10 according to the sixth embodiment disposes a CCE including resource
information for one MTC group in a predetermined sub carrier. According to the
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configuration, since an MTC terminal 20 simply needs to perform blind decoding on
only the predetermined sub carrier in a time direction, load related to the blind
decoding in the MTC terminal 20 can be reduced significantly.
[0140]
5 [2-7. Seventh embodiment]
The seventh embodiment is implemented by adapting the fourth
embodiment described with reference to FIG. 16 to the fifth embodiment.
Specifically, an MTC terminal 20 of the seventh embodiment belongs to an uplink
MTC group and a downlink MTC group. Due to this, the MTC terminal 20 is
10 assigned with MTC-DownLink_RNTI that is a group identifier for downlink, and
MTC-UpLink_RNTI that is a group identifier for uplink.
[0141]
In this case, the base station 10 generates the CCE including the uplink
resource information of the MTC group by using the MTC-UpLink_RNTI, and
15 generates the CCE including the downlink resource information by using the MTCDownLink_
RNTI.
[0142]
Due to this, the MTC terminal 20 can extract the CCE for the MTC group to
which the MTC terminal 20 belongs by performing blind decoding on each CCE in
20 the PDCCH by using the MTC-DownLink_RNTI and the MTC-UpLink_RNTI.
[0143]
<3. Conclusion>
As described above, according to the first embodiment to the fourth
embodiment of the invention, the resource information for a large number of MTC
25 terminals 20 can be stored by mapping the resource information (assign, grant) for
each MTC terminal 20 in the second search space in the PDSCH. Further, since a
number of the CCEs in the PDCCH can be suppressed, the search space in which the
MTC terminal 20 performs the blind decoding can be reduced. As a result, load
related to the blind decoding in the MTC terminal 20 can be reduced.
30 [0144]
Further, according to the fifth embodiment to the seventh embodiment of the
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invention, the resource information described in the CCE in the PDCCH can be
shared by the plurality of MTC terminals 20 in the MTC group. Due to this, the
resource information for each MTC terminal 20 no longer needs to be described in
separate CCEs, so the search space in the PDCCH can be made small. As a result,
5 load related to the blind decoding in the MTC terminals 20 can be reduced.
[0145]
Notably, although preferred embodiments of the invention have been
described in detail with reference to the attached drawings, the invention is not
limited to these examples. A person skilled in the art find various alterations and
10 modifications within the scope of the appended claims, and it should be understood
that they will naturally come under the technical scope of the present invention.
[0146]
For example, respective steps in the processes by the base station 10 and the
MTC terminal 20 in the description do not necessarily be performed in chronological
15 orders as described in sequence diagrams. For example, the respective steps in the
processes by the base station 10 and the MTC terminal 20 may be performed in
orders different from the orders described the in sequence diagrams, or may be
performed in parallel.
[0147]
20 Further, computer programs for causing hardware such as CPUs, ROMs,
and RAMs installed in the base station 10 and the MTC terminal 20 to exhibit similar
functions as the respective configurations of the base station 10 and the MTC
terminal 20 may be produced. Further, storage media storing such computer
programs may also be provided.
25
Reference Signs List
[0148]
10 Base station
12 MME
30 14 S-GW
16 PDN-GW
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20 MTC terminal
30 MTC server
104,204 Antenna
108,208 Radio processing section
5 112,212 Storage section
116 Scheduler
120 Control signal generating section
124, 224 CRC circuit
128 Data mapping section
10 220 Blind decoding section

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CLAIMS
Claim 1
A base station comprising:
5 a transmitter section that transmits a radio signal in a frame including a
control region and a data region;
a control signal generating section that generates a control signal which
includes reference information identified by a group identifier assigned to a plurality
of radio terminals and which is transmitted in the control region; and
10 a data signal generating section that generates a data signal by disposing
information for the plurality of radio terminals in a reference region indicated by the
reference information in the data region.
Claim 2
15 The base station according to claim 1, wherein the data signal generating
section disposes information for each of the plurality of radio terminals in the
reference region indicated by the reference information, the information being
identified by a terminal identifier of each of the plurality of radio terminals.
20 Claim 3
The base station according to claim 2, wherein the information for each of
the plurality of radio terminals includes uplink resource information or downlink
resource information.
25 Claim 4
The base station according to claim 3, wherein the uplink resource
information or the downlink resource information indicates a resource in a frame that
is provided after a frame in which the information for each of the plurality of radio
terminals is disposed.
30
Claim 5
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The base station according to claim 4, wherein the data signal generating
section disposes the information for the plurality of radio terminals in a same
reference region within the data region over a plurality of frames, the same reference
region being indicated by the reference information disposed in a control region of
5 one frame.
Claim 6
The base station according to claim 4, wherein
an uplink group identifier and a downlink group identifier are assigned to
10 the plurality of radio terminals,
the data signal generating section disposes uplink resource information for
each of the plurality of radio terminals in a reference region indicated by reference
information identified by the uplink group identifier, and
the data signal generating section disposes downlink resource information
15 for each of the plurality of radio terminals in a reference region indicated by
reference information identified by the downlink group identifier.
Claun?
The base station according to claim 6, wherein the control signal generating
20 section disposes reference information identified by a same group identifier in a
predetermined frequency region within the control region.
Claim 8
The base station according to claim 7, wherein the control signal generating
25 section adds a check bit obtained by masking the reference information with the
group identifier to the reference information.
Claim 9
A method for radio communication, the method comprising the steps of:
30 generating a control signal that is to be transmitted in a control region in a
frame including the control region and a data region, the control signal including
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reference information identified by a group identifier assigned to a plurality of radio
terminals;
generating a data signal by disposing information for the plurality of radio
terminals in a reference region indicated by the reference information in the data
5 region; and
transmitting the control signal and the data signal.
Claim 10
A program for causing a computer to function as:
10 a transmitter section that transmits a radio signal in a frame including a
control region and a data region;
a control signal generating section that generates a control signal which
includes reference information identified by a group identifier assigned to a plurality
of radio terminals and which is transmitted in the control region; and
15 a data signal generating section that generates a data signal by disposing
information for the plurality of radio terminals in a reference region indicated by the
reference information in the data region.
Claim 11
20 A radio communication system comprising:
a plurality of radio terminals; and
a base station that includes
a transmitter section that transmits a radio signal in a frame
including a control region and a data region,
25 a control signal generating section that generates a control signal
which includes reference information identified by a group identifier assigned to the.
plurality of radio terminals and which is transmitted in the control region, and
a data signal generating section that generates a data signal by
disposing information for the plurality of radio terminals in a reference region
30 indicated by the reference information in the data region.
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Claim 12
A radio terminal comprising:
a receiver section that receives a radio signal transmitted from a base station
in a frame including a control region and a data region; and
5 an acquiring section that acquires reference information identified by a
group identifier assigned to a plurality of radio terminals including the radio terminal
from a control signal received in the control region, and a data portion identified by a
terminal identifier assigned to the radio terminal from a data signal received in a
reference region indicated by the reference information in the data region.
10
Claim 13
The radio terminal according to claim 12, wherein the acquiring section
acquires the data portion identified by the terminal identifier assigned to the radio
terminal from the control signal received in the control region in a case of
15 determining that the group identifier is not used by the base station.
Claim 14
A method for radio communication performed by a radio terminal, the
method comprising the steps of:
20 receiving a radio signal transmitted from a base station in a frame including
a control region and a data region;
acquiring reference information identified by a group identifier assigned to a
plurality of radio terminals including the radio terminal from a control signal
received in the control region; and
25 acquiring a data portion identified by a terminal identifier assigned to the
radio terminal from a data signal received in a reference region indicated by the
reference information in the data region.
Claim 15
30 A program for causing a computer to function as a radio terminal that
includes:
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a receiver section that receives a radio signal transmitted from a base station
in a frame including a control region and a data region; and
an acquiring section that acquires reference information identified by a
group identifier assigned to a plurality of radio terminals including the radio terminal
5 from a control signal received in the control region, and a data portion identified by a
terminal identifier assigned to the radio terminal from a data signal received in a
reference region indicated by the reference information in the data region.