Description
Title of Invention
COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL
5 METHOD, COMMUNICATION SYSTEM AND COMMUNICATION DEVICE
Technical Field
[0001]
The present invention relates to a communication control device, a
10 communication control method, a communication system and a communication
device.
Background Art
[0002] •
15 Recently, discussions for enabling a primarily used frequency band
(spectrum) to be used in a second communication service according to the use
condition of the frequency band have been in progress. For example, a standard
specification for allowing an unused channel (TV white space) included in the
frequency band of US digital TV broadcasting to be available for radio
20 communication is under examination in IEEE802.22 working group (see Non-Patent
Literature 1 below).
[0003]
According to a recommendation of the Federal Communications
Commission (FCC) on November 2008, the discussions have been directed toward
25 permitting secondary usage of the TV white space by using a communication device
that fulfills a predetermined condition and has received an authentication. This
recommendation of FCC accepts the standard specification of IEEE802.22, which is
the first standardization of secondary usage of the TV white space, and also covers
the activities of a new study group in IEEE. Technically, since it is necessary to
30 perform signal detection at a level of -114 [dBm] (SNR is about -19 [dB] when Noise
Figure (NF) is 11 [dB], for example) using existing technology for example, an

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auxiliary function such as Geo-location Database Access is expected to be necessary
I,
(see Non-Patent Literature 2 below). Also, FCC is under examination for opening a
250-MHz band, which is a part of a 5-GHz band, as a new channel for secondary
usage. 5 [0004]
Furthermore, in the EU, there are moves afoot to universally allocate a
dedicated control channel referred to as Cognitive Pilot Channel (CPC) for i
implementing Dynamic Spectrum Access (DSA) under a long-term strategy.
Allocation of CPC has been incorporated in the agenda of International
10 Telecommunication Union (ITU)-WPll in 2011. Technological studies for a
secondary usage system that performs DSA are also under way in the IEEE
Standards Coordinating Committee (SCC) 41.
[0005] In general, when a frequency band assigned to a communication service
15 related to primary usage (will be referred to as a first commimication service below)
is secondarily used, it is important that a communication service related to secondary
usage (will be referred to as a second communication service below) not interfere
with the first communication service. For this reason, Non-Patent Literature 2
below recommends installation of a data server that receives administrator i
20 information, location information, and the like fi-om a secondary usage node which
will provide a second communication service and accumulates these pieces of
information in a database. In this case, the data server specifies a chaimel that can
be provided for secondary usage according to a request fi-om the secondary usage
node, and notifies the secondary usage node of the specified channel. When the
25 secondary usage node uses the channel notified in this way by the data server,
interference with a first commimication service is prevented. ;
Citation List
Non-Patent Literature
30 [0006]
Non-Patent Literature 1: "IEEE802.22 WG on WRANs," [online],
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[searched July 1st, 2010], Internet
Non-Patent Literature 2: "SECOND REPORT AND ORDER AND
MEMORANDUM OPINION AND ORDER," [online], [searched July 1st, 2010],
Internet
30 Solution to Problem
[0009]
i •
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According to an embodiment of the present disclosure, there is provided a
communication control device which controls communication of one or more
secondary usage nodes respectively providing second communication services using
a part of a frequency band assigned to a first commimication service, the
5 communication control device including a communication unit that receives access
technique information indicating radio access techniques usable by the corresponding
secondary usage nodes from the respective secondary usage nodes, a storage unit that
stores the access technique information received by the communication unit, and a
control unit that, when at least a portion of a service area of a second-order second
10 communication service is included in a service area of a first-order second
communication service, determines whether or not at least a part of communication
resources can be shared between the first-order second communication service and
the second-order second communication service on the basis of the radio access
i
techniques of the first-order second communication service and the second-order
15 second communication service indicated by the access technique information.
[0010]
The control unit may determine whether or not a part of the communication
resources can be shared between the first-order second communication service and
the second-order second communication service, if the service area of the second-
20 order second communication service is not included in the service area of the firstorder
second commimication service, even when a level of mutual interference
between the first-order second communication service and the second-order second
communication service exceeds an allowable interference level.
[0011]
25 The control unit may determine that a part of the communication resources
i
can be shared, when a radio access technique indicated by the access technique
information corresponding to the first-order second communication service is '.
OFDMA.
[0012] i
30 The control unit may determine that a part of the commimication resources
can be shared, when a radio access technique indicated by the access technique
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information corresponding to the first-order second communication service is
OFDMA, and a radio access technique indicated by the access technique information
corresponding to the second-order second communication service is CSMA.
[0013]
5 The control unit may determine whether or not a part of the communication
resources can be shared in response to a request from a secondary usage node
providing the second-order second communication service.
[0014]
The control unit may request a secondary usage node providing the first-
10 order second communication service to provide information specifying a range of
sharable communication resources, when it is determined that a part of the
communication resources can be shared. [0015]
The control unit may provide the information specifying the range of
15 sharable communication resources received from the secondary usage node
providing the first-order second communication service to a secondary usage node
providing the second-order second communication service. r
[0016] I
The control unit may supply a synchronization signal to the secondary usage ;
s
20 nodes respectively providing the first-order second communication service and the •
second-order second communication service, when there are sharable communication
resources. •
[0017] ;
The control unit may transmit control information for preventing
25 interference caused by sharing the communication resources to a secondary usage •
node providing the second-order second communication service, when there are
sharable communication resources.
[0018]
The communication unit may further receive the service area information
30 from the respective secondary usage nodes. The communication control device
may further include an estimation unit that estimates a service area of the first-order
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second communication service and a service area of the second-order second
communication service using service area information for estimating the service
areas of the second communication services provided by the secondary usage nodes.
[0019]
5 The control unit may reduce the service area of the second-order second
communication service in order to share the communication resources, when no
portion of the service area of the second-order second communication service is
included in the service area of the first-order second communication service.
[0020]
10 Further, according to another embodiment of the present disclosure, there is
provided a communication control method for controlling communication of a
plurality of secondary usage nodes respectively providing second communication
services using a part of a frequency band assigned to a first communication service,
the communication control method including receiving access technique information
15 indicating radio access techniques usable by the corresponding secondary usage
nodes from the respective secondary usage nodes, storing the received access
technique information, and when at least a portion of a service area of a second-order
second communication service is included in a service area of a first-order second I
communication service, determining whether or not at least a part of communication
20 resources can be shared between the first-order second communication service and
the second-order second communication service on the basis of the radio access I
techniques of the first-order and second-order second communication services
indicated by the access technique information.
[0021]
25 Further, according to another embodiment of the present disclosure, there is
provided a communication system which includes a plurality of secondary usage i
nodes respectively providing second commimication services usmg a part of a
frequency band assigned to a first communication service and a communication
control device controlling communication of the plurality of secondary usage nodes.
30 Each of the secondary usage nodes includes a communication unit that transmits
access technique information indicating radio access techniques usable by the
!
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corresponding secondary usage nodes to the communication control device. The
communication control device includes a commimication unit that receives the
access technique information from the respective secondary usage nodes, a storage
unit that stores the access technique information received by the communication unit,
5 and a control unit that, when at least a portion of a service area of a second-order
second conmiunication service is included in a service area of a first-order second
communication service, determines whether or not at least a part of communication
resources can be shared between the first-order second communication service and
the second-order second communication service on the basis of the radio access
10 techniques of the first-order second communication service and the second-order
second communication service indicated by the access technique information.
[0022]
Further, according to another embodiment of the present disclosure, there is
provided a communication device which provides a second communication service
15 using a part of a fi-equency band assigned to a first communication service, the
communication device including a commimication unit that transmits access
technique information indicating a radio access technique usable by the
communication device to another device in order to cause the other device to
determine whether or not it is necessary to share a part of communication resources
20 of the second communication service with another second communication service,
and a secondary usage control unit that specifies a range of communication resources
sharable with the other second communication service in response to a request fi-om
the other device when the other device determines that a service area of the second
communication service includes a service area of the other second communication
25 service, and it is necessary to share a part of the communication resources of the
second communication service on the basis of the access technique information.
Advantageous Effects of Invention
[0023]
30 As described above, according to the communication control device, the
communication control method, the communication system, and the communication
:
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device related to the present disclosure, it is possible to support sharing of
communication resources between a plurality of second communication services.
Brief Description of Drawings
5 [0024]
[Fig. 1] Fig. 1 is an explanatory diagram illustrating an outline of a communication
system related to one embodiment.
[Fig. 2] Fig. 2 is a sequence diagram showing an example of the flow of a process
between a secondary usage node and a data server.
10 [Fig. 3] Fig. 3 is a block diagram showing an example of a configuration of a
communication control device related to one embodiment.
[Fig. 4] Fig. 4 is an explanatory diagram illustrating an example of a resource
arrangement when communication resources are shared.
[Fig. 5] Fig. 5 is an explanatory diagram illustrating a first example of a location
15 relationship between service areas of second communication services.
[Fig. 6] Fig. 6 is an explanatory diagram illustrating a second example of a location
relationship between service areas of second communication services.
[Fig. 7] Fig. 7 is an explanatory diagram illustrating a third example of a location
relationship between service areas of second communication services.
20 [Fig. 8] Fig. 8 is an explanatory diagram illustrating a fourth example of a location
relationship between service areas of second communication services.
[Fig. 9] Fig. 9 is a block diagram showing an example of a configuration of a
secondary usage node related to one embodiment.
[Fig. 10] Fig. 10 is a sequence diagram showing an example of the flow of a
25 communication control process between a communication control device and a
secondary usage node related to one embodiment.
[Fig. 11] Fig. 11 is a flowchart showing an example of the flow of a service area ;
estimation process related to one embodiment.
[Fig. 12] Fig. 12 is a first part of a flowchart showing an example of the flow of a
30 process of determining a recommended service configuration related to one
embodiment.
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[Fig. 13] Fig. 13 is a second part of the flowchart showing an example of the flow of
the process of determining a recommended service configuration related to one
embodiment.
[Fig. 14] Fig. 14 is a third part of the flowchart showing an example of the flow of
5 the process of determining a recommended service configuration related to one
embodiment.
[Fig. 15] Fig. 15 is a sequence diagram showing an example of the flow of a process
of supporting sharing of communication resources related to one embodiment.
10 Description of Embodiments
[0025]
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 function
15 and structure are denoted with the same reference signs, and repeated explanation is
omitted.
!
[0026]
"Embodiments for Implementing Invention" will be described according to
the following sequence.
20 1. Outline of System
2. Example of Configuration of Device Related to One Embodiment I
2-1. Example of Configuration of Communication Control Device
2-2. Example of Location Relationship Between Service Areas i
2-3. Example of Configuration of Secondary Usage Node
25 3. Flow of Process Related to One Embodiment
3-1. Commumcation Control Process
3-2. Service Area Determmation Process
3-3. Process of Determining Recommended Service Configuration
3-4. Process of Supporting Sharing of Communication Resources
30 4. Summarization
[0027]
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<1. Outline of System>
Fig. 1 is an explanatory diagram illustrating an outline of a communication
system related to one embodiment. Referring to Fig. 1, a primary usage node 10,
secondary usage nodes 20a and 20b, a data server 40, and a communication control
5 device 100 are shown.
[0028]
The primary usage node 10 is a node that transmits/receives radio signals
for a first communication service using a frequency band w^hich has been assigned in
advance. However, the primary usage node 10 does not necessarily use the
10 assigned whole frequency band. In the example of Fig. 1, a frequency band
including channels Fl, F2 and F3 has been assigned, but the primary usage node 10
is using only the channel Fl and F2 among them. The first communication service
may be an arbitrary communication service including, for example, a digital TV
broadcasting service, a satellite communication service, a mobile communication 15 service, or the like. In addition, for example, when the first communication service
is a mobile communication service, the primary usage node 10 can correspond to a
base station.
[0029]
A boundary BOl shown in Fig. 1 is an external boundary of a service area of
20 the first communication service provided by the primary usage node 10. A terminal
device (not shown) that is located within the boundary BOl can receive the first
communication service provided by the primary usage node 10. A boundary B02 is
an external boundary of a guide area set around the service area of the first
communication service. The guide area is a buffer area set between the service area
25 of the first communication service and a so-called white space. Since there is the
guide area, even when a fi-equency band is secondarily used in the white space, a
probability that a problem such as interference will occur in the terminal device
located in the service area is reduced.
[0030]
30 Between the boundary B02 and a boundary BOS, the so-called white space is
present. In the example of Fig. 1, the secondary usage nodes 20a and 20b are
: \ •
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located in the white space. Each of the secondary usage nodes 20a and 20b is a
communication device that provides a second communication service using a part of
the frequency band assigned to the first commimication service. In the following
description of this specification, when there is no particular necessity to distinguish
5 the secondary usage nodes 20a and 20b from each other, letters at the ends of the
symbols are omitted, and the secondary usage nodes 20a and 20b will be generally
referred to as secondary usage nodes 20.
[0031]
A secondary usage node 20 determines whether or not secondary usage is ^
10 available according to a predetermined spectrum policy, receives a channel provided
by the data server 40, and then provides a second communication service to terminal
devices (not shown) located around it. In the example of Fig. 1, the channel F3
which is not used by the primary usage node 10 may be provided to both the
secondary usage node 20a and the secondary usage node 20b. Note that without
15 being limited to the example of Fig. 1, the secondary usage node 20 may be located
in the service area of the first communication service or around the service area. i
For example, in order to cover a spectrum hole that is generated in the service area
[
due to the influence of shadowing (shielding), fading, or the like, a secondary usage
node may be installed in the service area of the first commvmication service.
20 [0032]
The second communication service typically denotes an additional or
substitutionary communication service that is provided using a part or the whole of a
frequency band assigned to the first communication service. In the meaning of the
term "secondary usage," the first communication service and the second
25 communication service may be communication services of different types or services
of the same type. Communication services of different types denote
communication services of two or more different types that can be selected from
arbitrary communication services, for example, a digital TV broadcasting service, a
satellite communication service, a mobile communication service, a wireless LAN
30 access service, a Peer-To-Peer (P2P) connection service, and the like. On the other
hand, services of the same type can include a relationship between a service based on
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a macro-cell provided by a communication provider, for example, of a mobile
communication service, and a service based on a femto-cell managed by a user or a
Mobile Virtual Network Operator (MVNO). In addition, services of the same type
can also include a relationship between a service provided by a base station of a
5 communication service according to WiMAX, Long Term Evolution (LTE), LTEAdvanced
(LTE-A), or the like and a service provided by a relay station (relay node)
to cover a spectrum hole. Also, the second communication service may be a service
that uses a plurality of fragmentary frequency bands aggregated using spectrum
aggregation technology. Furthermore, the second communication service may be a
10 supplementary commimication service that is provided by a femto-cell group, a relay
station group, or a small or medium-sized base station group, which provides a
smaller service area than a base station, present within a service area of the base
station. The outline of each embodiment described in this specification is widely
applicable to every type of mode of such secondary usages.
15 [0033]
The data server 40 has a database that receives node information including
administrator information, location information, and the like from the secondary
usage node 20 and accumulates the received node information. The data server 40
can be connected with the primary usage node 10 and the secondary usage node 20
20 via, for example, the Internet, a backbone network of the first communication service,
or the like. The data server 40 accumulates the aforementioned node information
received from the secondary usage node 20. Also, according to a request from the
secondary usage node 20, the data server 40 provides information, for example, a
channel that can be provided for secondary usage, maximum transmission power, a
25 spectrum mask, and the like to the secondary usage node 20. In this way, the
secondary usage node 20 becomes able to start the second communication service.
[0034]
Fig. 2 is a sequence diagram showing an example of the flow of a process
between the secondary usage node 20 and the data server 40 exemplified in Fig. 1.
30 Referring to Fig. 2, the secondary usage node 20 that will secondarily use a
frequency band assigned to the first communication service transmits node
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information to the data server 40 first, thereby requesting registration of the node
information (step S02). Then, the data server 40 registers the node information
received from the secondary usage node 20 in a database (step S04).
[0035]
5 Here, the node information registered in the database includes, for example,
the following information:
• Regulation ID: an ID given vs^hen a node is authenticated as a device that can be
used for secondary usage. The regulation ID can be included in node information in
the case of secondary usage of a TV white space.
10 • Manufacturer ID: an ID of a manufacturer of the device.
• Location Data: indicates a location of the device that is dynamically measured
using a positioning means such as GPS, or kept stationary.
• Antenna Height: a height of an antenna of the device. For example. Height Above
Average Terrain of the tx (HAAT) can be used.
15 • Administrator Information: includes a device owner's name, address, mail address,
and the like.
[0036]
Next, the data server 40 transmits an acknowledgement signal
(confirmation) confirming that registration of the node information has been finished
20 to the secondary usage node 20 (step S06). Next, the secondary usage node 20
requests permission for secondary usage fi-om the data server 40 (step SOS). Then,
the data server 40 determines, for example, a channel that can be provided to the
secondary usage node 20 (for example, an unused part of a frequency band assigned
to the first communication service), and permits secondary usage to the secondary
25 usage node 20 when there is a providable channel (step SIO).
[0037]
i
In step SIO, the data server 40 provides the secondary usage node 20 with,
for example, the following information:
• Maximum Transmission Power: a maximum of transmission power at which the
30 secondary usage node 20 is allowed to perform radiation. !
• Permissible Channel Information: a list of channel numbers specifying channels

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that can be provided to the secondary usage node 20. The frequency band assigned
to the first communication service can be divided into a pluraUty of channels in
advance, and channel nimibers can be given to the respective channels. Instead of
the channel numbers, center frequencies of the channels may be used.
5 • Regulatory Information: can include rules for secondary usage such as a spectrum
mask.
In this specification, these pieces of information that are provided fi"om the
data server 40 to the secondary usage node 20 are referred to as grant information.
[0038]
10 After these steps, the secondary usage node 20 can start secondary usage of
the fi-equency band assigned to the first communication service.
[0039]
The communication control device 100 is a communication device that
controls communication of one or more secondary usage nodes 20. Like the data
15 server 40, the communication control device 100 also can be connected with the
primary usage node 10 and the secondary usage nodes 20 via, for example, the
Internet, the backbone network of the first commimication service, or the like. The
communication control device 100 may be physically the same device as the
database 40. The communication control device 100 adjusts a configuration of
20 radio access techniques, channels, and the like of second communication services
provided by the respective secondary usage nodes 20 between the plurality of second
communication services using node information about the secondary usage nodes 20,
information provided by the data server 40, and the like. Accordingly, in the cases
in which communication resources can be shared according to a combination of radio
25 access techniques, the communication control device 100 supports sharing of
communication resources between a plurality of second communication services, as
will be described in detail in the next chapter. ;
[0040]
<2. Example of Configuration of Device Related to One Embodiment >
30 [2-1. Example of Configuration of Communication Control Device] I
Fig. 3 is a block diagram showing an example of a configuration of the

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communication control device 100 related to this embodiment. Referring to Fig. 3,
the communication control device 100 includes a communication unit 110, a storage
unit 120, an estimation imit 130, and a control unit 140.
[0041]
5 (Communication Unit)
The communication unit 110 is a communication interface for the
communication control device 100 to commimicate with the secondary usage nodes
20. In addition, the communication unit 110 may be able to communicate with the
data server 40. In this embodiment, the communication unit 110 receives a request
10 for registration of secondary usage from, for example, each secondary usage node 20
to which secondary usage is permitted.
[0042]
The request for registration of secondary usage includes, for example, the

following information:
15 • Regulation ID: information that can be registered as node information in a data
server. • Manufacturer ID: information that can be registered as node information in a data ;
server.
• Location Data: information that can be registered as node information in a data
20 server.
• Antenna Height: information that can be registered as node information in a data
server. i
• Maximum Transmission Power: information that can be provided as grant
information from a data server.
25 • Permissible Channel Information: information that can be provided as grant
information from a data server. ,

• Regulatory Information: information that can be provided as grant information
from a data server.
• Utilization Channel Information: a number of a channel that a secondary usage '
30 node will use for a second communication service among channels included in a list
of permissible channel information.

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• Access Technique Information: a list of access technique numbers indicating radio
access techniques that can be used (and are currently in use) by a secondary usage
node. The numbers can be given in advance according to each radio access
technique such as IEEE802.11af, llg or lln, IEEE802.22, IEEE802.16, LTE, LTE-A,
5 or the like. Instead of a list of access technique numbers, the access technique
information may include a bit string, a code value, or the like that indicates whether
or not respective radio access techniques are supported. Also, the access technique
information may include information indicating whether or not a protocol for
coexistence of commimication services, which will be described later, can be used.
10 [0043]
In this embodiment, the communication control device 100 handles the
location data, the antenna height, and the maximum transmission power among these
pieces of information as service area information for estimating a service area of a
second communication service provided by the secondary usage node 20. The
15 information mentioned here is merely an example. In other words, the request for
registration of secondary usage that is transmitted from the secondary usage node 20
to the communication control device 100 may not include a part of the
aforementioned information, or may further include additional information. Also,
the communication control device 100 may acquire a part of the aforementioned
20 information not from the secondary usage node 20 but from the data server 40.
[0044]
The communication unit 110 stores information received from each
secondary usage node 20 in the storage unit 120. Also, the commimication unit 110
receives an adjustment request from a secondary usage node 20 that requests an
25 adjustment between second communication services. The adjustment request from
the secondary usage node 20 is processed by the control unit 140 which will be
described later.
[0045]
(Storage Unit) i
30 The storage unit 120 is implemented using a storage medium, for example, a
hard disc, a semiconductor memory, or the like. In this embodiment, the storage ;
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unit 120 stores information included in the registration request that is received by the
communication unit 110. Among the information stored in the storage unit 120, the
service area information including the location data, the antenna height, and the
maximum transmission power of the secondary usage node 20 can be used by the
5 estimation unit 130, which will be described later, to estimate a service area. Also,
the permissible channel information, the utilization channel information, and the
access technique information can be used for an adjustment between second
communication services by the control unit 140 which will be described later.
[0046]
10 (Estimation Unit)
The estimation imit 130 estimates a service area of the second
communication service provided by the secondary usage node 20 using the service
area information stored by the storage unit 120, that is, the location data, the antenna
height, and the maximum transmission power of the secondary usage node 20. For
15 example, the estimation unit 130 approximates that the service area of the second
service provided by the secondary usage node 20 is a circular area centered on the
location of the secondary usage node 20.
[0047]
As methods for estimating a radius of a service area, two methods are
20 considered. A first method is a method that is disclosed in "Method for point-toarea
predictions for terrestrial services in the frequency range 30 mhz to 3000 mhz"
(International Telecommunications Commission (ITU), RECOMMENDATION ITUR
PI546-3, 2007) and uses a propagation path curve. In this case, a statistical curve
(propagation path curve) that is based on an actual measurement value for deriving a
25 communication distance (a distance at which communication is enabled with a
predetermined location rate and a predetermined time rate) from an anterma height
and electric field intensity is stored in advance by the storage unit 120. The
estimation unit 130 converts the maximum transmission power of the secondary
usage node 20 into electric field intensity, and acquires a communication distance
30 corresponding to the antenna height and electric field intensity of the secondary
usage node 20 from the propagation path curve stored in the storage unit 120. This

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communication distance becomes a radius of the service area of the second
communication service provided by the secondary usage node 20.
[0048]
A second method for estimating a radius of a service area is a method
5 employing an evaluation formula in the urban model of Okumura-Hata curve (see
"Digital Wireless Transmission Technology" (written by Seiichi Sampei, Pearson
Education Japan, pp. 16-19)). In this case, the estimation xmit 130 calculates a
maximum allowable path loss from the maximum transmission power of the
secondary usage node 20 and a minimum reception sensitivity of a receiver. Then,
10 the estimation unit 130 substitutes the calculated path loss and the antenna height in
the evaluation formula, thereby calculating a communication distance. This
communication distance becomes a radius of the service area of the second
communication service provided by the secondary usage node 20.
[0049]
15 The estimation unit 130 causes the storage unit 120 to store a value that is
estimated in this way and indicates a service area of a second communication service
of each secondary usage node 20 (for example, a center position and a radius of a
circle).
[0050]
20 (Control Unit)
The control unit 140 adjusts a configuration for secondary usage between
second communication services on the basis of a location relationship between
service areas estimated by the estimation unit 130 and a radio access technique that
can be used by the secondary usage nodes 20. The adjustment of a configuration
25 for secondary usage between second communication services includes a
recommendation about a radio access technique or a recommendation about a
channel to be used for at least one secondary usage node 20 in terms of, for example,
increase in secondary usage opportunities, improvement in frequency use efficiency,
or the like. In addition, the control unit 140 determines whether or not a part of
30 communication resources of a first-order second communication service can be
shared with a second-order second communication service according to a location ;

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relationship between a service area of the first-order second communication service
and a service area of the second-order second communication service.
[0051]
For example, when a radio access technique indicated by access technique
5 information corresponding to the first-order second communication service is
OFDMA, the control unit 140 may determine that a part of the communication
resources can be shared. For example, IEEE803.22 is a radio commxmication
protocol that is also referred to as a Wireless Regional Area Network (WRAN) and
employs OFDMA. In a radio communication protocol that employs OFDMA,
10 communication resources can be divided into relatively small units that are referred
to as sub-carriers in a fi-equency direction and symbols in a time direction. A base
station schedules communication in units of resource blocks that include a
predetermined number of sub-carriers and a predetermined number of symbols. In
this embodiment, the base station can correspond to a secondary usage node 20 that
15 provides the first-order second commimication service. Accordingly, in this case,
the control unit 140 negotiates with the secondary usage node 20 that provides the
first-order second communication service using OFDMA, receives the distribution of
sharable communication resources, and thereby can implement sharing of
communication resources. In other words, when a radio access technique of the
20 first-order second communication service is OFDMA, it is easier to implement
sharing of communication resources in comparison with a case in which another
radio access technique is employed.
[0052]
•
Furthermore, for example, when a radio access technique indicated by the
25 access technique information corresponding to the second-order second
communication service is CSMA, the control unit 140 may determine that a part of
the communication resources can be shared. For example, IEEE802.il (11a, lib, I
llg, lln, or the like) is a radio communication protocol that employs Carrier Sense
Muhiple Access with Collision Avoidance (CSMA/CA). Unlike OFDMA, CSMA
30 is a technique in which a base station does not schedule communication in a
centralized manner, but rather, a terminal device can start communication at an
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arbitrary timing according to a predetermined collision avoidance (or collision
detection) sequence. Thus, the second-order second communication service
employing CSMA is appropriate for flexibly performing communication according to
a timing in a section of communication resources that is determined to be distributed
5 from the first-order second commimication service.
[0053]
When it is determined that a part of the communication resources can be
shared, the control unit 140 requests sharing of the communication resources from
the secondary usage node 20 providing the first-order second communication service.
10 This request demands provision of shared resource information for specifying a
range of sharable communication resources. In order to specify the range of
sharable communication resources, the shared resource information can include
information, for example, a start timing, an end timing, a period, a center frequency
(or a chaimel number), and the like of the sharable communication resources.
15 When the shared resource information is received from the secondary usage node of
the first-order second corrmiunication service, the control unit 140 transmits the
shared resource information to a secondary usage node 20 of the second-order
second communication service, thereby supporting sharing of communication
resources. Also, in order to support, for example, synchronization with the
20 secondary usage node 20 of the first-order second corrmiunication service by the
secondary usage node 20 of the second-order second commimication service, the
confrol unit 140 may supply a synchronization signal to the respective secondary
usage nodes 20 through the commvinication unit 110.
[0054]
25 Fig. 4 is an explanatory diagram illustrating an example of a resource
arrangement when conmiunication resources are shared in this embodiment.
Referring to Fig. 4, a resource arrangement is shown in a time-frequency domain of
which a horizontal axis is a time axis and of which a vertical axis is a frequency axis.
In the drawing, one cell surrounded by dotted lines denotes the minimum unit of
30 scheduling in OFDMA, and there are cases in which this cell is referred to as a '
resource block. The minimum unit of one round of scheduling can include n sub- ;

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carriers and m symbols. Among these communication resources, the secondary
usage node 20 of the first-order second communication service distributes, for
example, a CSMA slot of a center frequency Fmid in a section from a start timing Tstart
to an end timing Tend at intervals INT for the second-order second communication
5 service. The start timing Tstart and the end timing Tend are designated by using, for
example, a reference signal transmitted from the secondary usage node 20 of the
first-order second communication service as a reference. In addition, these timings
can be corrected between the secondary usage nodes 20 by the synchronization
signal supplied from the communication control unit 100. The secondary usage
10 node 20 of the first-order second communication service transmits, for example,
information including the start timing Tstart, the end timing Tend» the center frequency
Fmid, and the interval INT to the communication control device 100 as shared
resource information for specifying a range of sharable communication resources.
[0055]
15 In addition, as exemplified in Fig. 4, the secondary usage node 20 of the
first-order second communication service may install a guard slot between
communication resources distributed to the second-order second communication
•
service (a CSMA slot) and the surrounding communication resources for the firstorder
second communication service (OFDMA slots). In this way, even when the
20 first-order and second-order second communication services are not fully
synchronized, or there is an error in a frequency used as a reference, the first-order
and second-order second communication services can favorably share
communication resources without interfering with each other.
[0056]
25 In addition, when, for example, there is a large amoimt of traffic for the
first-order second commimication service, and there are not enough spare
communication resources, the secondary usage node 20 of the first-order second
communication service may reject sharing of communication resources. On the
other hand, when there are enough spare communication resources, or some slots are
30 not used for a long time period due to the influence of frequency selective fading, or
in other similar situations, sharing of communication resources can be accepted.

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[0057]
[2-2. Example of Location Relationship Between Service Areas]
Location relationships between service areas based on which the control
unit 140 makes an adjustment between second communication services are classified
5 into, for example, four classes (referred to as class A, class B, class C and class D)
exemplified in Fig. 5 to Fig. 8.
[0058]
(Class A)
Referring to Fig. 5, an example of a location relationship between service
10 areas that belongs to class A is shown, hi Fig. 5, a service area All of the
secondary usage node 20a and a service area A12 of the secondary usage node 20b
overlap. In addition, the secondary usage node 20b is included in the service area
•
All of the secondary usage node 20a. Likewise, the secondary usage node 20a is
included in the service area A12 of the secondary usage node 20b. In such a
15 location relationship, radio waves transmitted by these adjacent secondary usage
nodes 20a and 20b become mutual interference factors, and there is a probability that
a problem will occur in secondary usage. In addition, a case in which only one of
the two secondary usage nodes 20 is included in a service area of the other may be
included in class A.
20 [0059]
For example, when service areas of two second communication services
have the location relationship of class A, the control unit 140 further determines
whether or not there is a common radio access technique that can be used by the two
secondary usage nodes 20a and 20b which provide the two second communication
25 services respectively. For example, when the secondary usage node 20a can use
radio access techniques Rl and R2, and the secondary usage node 20b can use the
radio access technique Rl, the radio access technique Rl is determined as a common
radio access technique. When there is a common radio access technique as
mentioned above, the control unit 140 recommends that the secondary usage nodes
30 20a and 20b use the common radio access technique and a common channel. In this
way, for example, the communication services are caused to coexist, or a mesh

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network is formed between the secondary usage nodes 20a and 20b, so that the
second communication services can be managed without interfering with each other.
For example, lis in the IEEE802.22, Ecma392, and IEEE802.il families, 16j in the
IEEE802.16 (WiMax) family, and the like support a mesh protocol or a protocol for
5 exchanging scheduling information. Accordingly, communication services can
coexist between communication services that employ these radio access techniques.
There is a case in which the IEEE802.il family supports a function for acquiring
resource usage information about an adjacent network through an access point or a
terminal in a method such as beacon request using a public action frame, and the like.
10 In this case also, communication services can coexist in the same way. Even if
usable radio access techniques are different (not the same), when a combination of
the radio access techniques is a combination of which the radio access techniques can
coexist, the control unit 140 can cause two commvmication services to coexist in a
common channel. This is the same for the other classes that will be described
15 below. Also, when usable radio access techniques are different from each other and
are not able to coexist, the control unit 140 recommends that the secondary usage
node 20a or 20b, which provides one second communication service, use a second
channel that is different from a first channel used by the other second communication
service. At this time, it is more preferable that the second channel not be adjacent
20 to the first chaimel on the frequency axis because interference by out-of-band
radiation is also prevented. In this way, it is possible to separately manage the
second communication service of the secondary usage node 20a and the second
communication service of the secondary usage node 20b without them interfering
with each other.
25 [0060]
(Class B)
Referring to Fig. 6, an example of a location relationship between service
areas that belongs to class B is shown. In Fig. 6, the service area All of the
secondary usage node 20a and the service area A12 of the secondary usage node 20b
30 overlap. However, the secondary usage node 20b is not included in the service area
All of the secondary usage node 20a, and the secondary usage node 20a is not
SP306380WO00
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included in the service area A12 of the secondary usage node 20b. In such a
location relationship, radio waves interfere with a terminal device 22a located in the
overlapping area, and there is a probability that a partial problem will occur in
secondary usage.
5 [0061]
For example, when service areas of two second communication services
have the location relationship of class B, the control unit 140 further determines
whether or not there is a common radio access technique that can be used by the two
secondary usage nodes 20a and 20b which provide the two second communication
10 services respectively. When there is a common usable radio access technique, the
control unit 140 recommends that the secondary usage nodes 20a and 20b use the
common radio access technique and a common channel. In this way, like in the
case of class A, it is possible to manage the second communication services without
them interfering with each other. However, in the case of class B, the secondary
15 usage nodes 20a and 20b are not able to directly receive signals transmitted by the
counterparts. For this reason, in this case, the control unit 140 causes the
communication unit 110 to transmit a synchronization signal to the two secondary
usage nodes 20a and 20b, thereby supporting coexistence of the communication
services or formation of a mesh network. Like in the case of class A, when usable
20 radio access techniques are different and are not able to coexist, the control unit 140
recommends that the secondary usage node 20a or 20b, which provides one second
communication service, use a channel (suitably, non-adjacent channel) that is
different from a channel used by the other second communication service.
[0062]
25 (Class C)
Referring to Fig. 7, an example of a location relationship between service
areas that belongs to class C is shown. In Fig. 7, the service area Al 1 of the
secondary usage node 20a and the service area A12 of the secondary usage node 20b
do not overlap. In such a location relationship, the control unit 140 recommends,
30 for example, that the two secondary usage nodes 20a and 20b, which provide two
second communication services respectively, use a common channel irrespective of
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usable radio access techniques. In this way, it is possible to increase a selection of
channels for a secondary usage node 20 that provides another second communication
service (not shown). However, in class C also, when mutual interference between
nodes of two second communication services (for example, interference between
5 nodes located in external boundary portions of two service areas) exceeds an
allowable level, the control unit 140 may perform control for sharing commimication
resources, like in class A and class B described above.
[0063]
In addition, the control unit 140 selects, for example, a chaimel to be
10 recommended to each secondary usage node 20 from among chaimels indicated by
permissible channel information received from the secondary usage node 20. This
means that an adjustment between second communication services by the
communication control device 100 can be performed within the range of regulation
for secondary usage (legal regulation of each country, regulation determined between
15 service providers, or the like). Accordingly, even when the secondary usage node
20 receives a notification from the communication control device 100 and changes a
channel, there is no risk of interfering with the first commimication service or other •
communication services that can be managed around the secondary usage node 20.
[0064]
20 (Class D)
Referring to Fig. 8, an example of a location relationship between service
areas that belongs to class D is shown. In Fig. 8, a service area All of the
secondary usage node 20a is included in a service area A12 of the secondary usage
node 20b. In such a location relationship, like in the case of class A, radio waves
25 transmitted by these adjacent secondary usage nodes 20a and 20b become mutual [
interference factors, and there is a probability that a problem will occur in secondary
usage.
[0065]
For example, when service areas of two second communication services
30 have the location relationship of class D, the control unit 140 first determines
whether or not it is possible to use a common radio access technique and a common
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channel, like in the case of class A. When it is possible to use a common radio
access technique and a common channel, use of the common radio access technique
and the common channel can be recommended. Also, when usable radio access
techniques are different and are not able to coexist, the control unit 140 determines
5 whether or not the two second communication services can use different channels.
When it is possible to use different channels, use of the different channels can be
recommended. In this regard, for example, when channels that have been permitted
to the two secondary usage nodes 20a and 20b by the data server 40 are the same one
channel, the secondary usage nodes 20a and 20b are not able to use different
10 channels. In this case, the control unit 140 supports sharing of communication
resources according to the radio access techniques that can be used by the secondary
usage nodes 20a and 20b. For example, as mentioned above, when a radio access
technique of the secondary usage nodes 20b is OFDMA, or the radio access
technique of the secondary usage nodes 20b is OFDMA and a radio access technique
15 of the secondary usage nodes 20a is CSMA, the control unit 140 may support sharing
of communication resources. In this way, the two second conmiunication services
having the location relationship of class D also can favorably coexist.
[0066]
Here, the communication control device 100 may support sharing of
20 communication resources after reducing the service area All by lowering a
transmission power of the secondary usage node 20a so that the location relationship
between the service areas becomes class D. Also, even when the service area All
is not fiiUy included in the service area A12 but includes a portion located outside the
service area A12, the location relationship between the service areas may be
25 recognized as class D. Even in this case, the communication control device 100 can
support sharing of communication resources according to the radio access techniques
that can be used by the secondary usage nodes 20a and 20b. At this time, the
communication control device 100 may avoid the risk of a radio signal transmitted
fi-om the outside of the service area A12 interfering with another communication
30 service using, for example, technology such as transmission power control,
beamforming, or the like.
I
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[0067]
[2-3. Example of Configviration of Secondary Usage Node]
Fig. 9 is a block diagram showing an example of a configuration of the
secondary usage node 20 related to this embodiment. The secondary usage node 20
5 may be a communication device that provides an arbitrary second communication
service, for example, a small or medium-sized base station, a wireless relay station, a
radio access point, or the like. Thus, there is a probability that the secondary usage
node 20 will have a variety of components according to its role. However, in Fig. 9,
only components that are directly related to this embodiment are shown. Referring
10 to Fig. 9, the secondary usage node 20 includes a first communication unit 210, a
second communication imit 220, a storage unit 230, and a secondary usage control
unit 240.
[0068]
(First Communication Unit)
15 The first communication unit 210 is a communication interface for the
secondary usage node 20 to communicate with the data server 40 and the
communication control device 100. For example, according to control of the
secondary usage control unit 240, the first communication unit 210 transmits a
request for registration of the node information, which has been described with
20 reference to Fig. 2, to the data server 40 and receives a registration acknowledgement
of the node information. Also, for example, according to control of the secondary
usage control unit 240, the first communication unit 210 transmits a request for
secondary usage permission to the data server 40 and receives grant information '
including a response from the data server 40. Further, the first conmiunication unit
25 210 transmits a request for an adjustment between second communication services,
which will be described in detail later, to the communication control device 100, and receives information about a recoirmiended service configuration that is transmitted
as a result of the adjustment fi-om the commvmication control device 100. !
[0069]
30 (Second Communication Unit)
The second communication unit 220 is a communication interface for the
;
'•
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secondary usage node 20 to provide a second communication service to terminal
devices around it. A radio access technique supported by the second
communication unit 220 may be an arbitrary method such as IEEE802.11af, llg or
lln, IEEE802.22, LTE, LTE-A, or the like. Access technique information that
5 indicates the radio access technique supported by the second communication unit 220
is stored in advance in the storage unit 230.
[0070]
(Storage Unit)
The storage unit 230 is implemented using a storage medium, for example, a
10 hard disc, a semiconductor memory, or the like. In this embodiment, the storage
unit 230 stores in advance the aforementioned node information that the secondary
usage node 20 registers in the data server 40. Also, the storage unit 230 stores the
aforementioned access technique information in advance. When the
aforementioned grant information is provided from the data server 40, the storage
15 unit 230 stores the grant information. Further, the secondary usage node 20 stores,
as utilization channel information, a niunber of a channel that the secondary usage
control unit 240 will use for the second communication service.
[0071] ;
(Secondary Usage Control Unit)
20 The secondary usage control unit 240 controls a series of processes for
secondary usage of a frequency band by the secondary usage node 20. For example,
the secondary usage control unit 240 performs a process with the data server 40
exemplified in Fig. 2 through the first communication unit 210. Also, the
secondary usage control unit 240 determines the necessity for an adjustment between
25 second communication services, and transmits an adjustment request to the
communication control device 100 when the adjustment is necessary. The case in
which the adjustment between second communication services is necessary can
include, for example, a case in which secondary usage is started according to
permission from the data server 40, but it is not possible to obtain commimication
30 quality as expected due to interference between the second communication services.
The case in which the adjustment between second communication services is
SP306380WO00
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necessary can further include, for example, a case in which although permission for
secondary usage is received from the data server 40, another communication service
has already started on the channel permitted and an opportunity for secondary usage
cannot be given. An example of a process after the secondary usage control unit
5 240 transmits the adjustment request will be described in detail in the next chapter.
Without receiving the adjustment request from the secondary usage node 20, the
j
communication control device 100 may voluntarily make the adjustment between the
I
second communication services in order to improve efficiency in frequency usage.
[0072]
10 <3. Flow of Process Related to One Embodiment>
Next, with reference to Fig. 10 to Fig. 15, description will be made
regarding the flow of a commimication control process between the communication
control device 100 and the plurality of secondary usage nodes 20 related to this i
embodiment. The communication control process described here can be performed
15 on each combination of, for example, a secondary usage node 20 that has requested
an adjustment between second communication services and one or more other
secondary usage nodes 20 located around the secondary usage node 20.
[0073]
[3-1. Communication Confrol Process]
20 Fig. 10 is a sequence diagram showing an example of the flow of a
communication control process between the communication confrol device 100 and
the secondary usage nodes 20a and 20b related to this embodiment. It is assumed
that node information has been registered in the data server 40 by the secondary
usage nodes 20a and 20b before the process of Fig. 10, and permission for secondary
25 usage has already been given to the secondary usage nodes 20a and 20b.
[0074]
Referring to Fig. 10, first, the secondary usage node 20b requests the
communication control device 100 to register secondary usage (step SI02). As
mentioned above, a registration request transmitted from the secondary usage node
30 20b includes service area information for estimating a service area of a second
communication service provided by the secondary usage node 20b, access technique
I ',
1 f
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information, and the like. Then, the communication control device 100 stores the
information received from the secondary usage node 20b in the storage unit 120 (step
SI04). The communication control device 100 transmits an acknowledgement
signal (confirmation) confirming that the registration has been finished to the
5 secondary usage node 20b (step S106).
[0075]
The secondary usage node 20a requests registration of secondary usage
from the communication control device 100 (step SI08). The registration request
transmitted fi-om the secondary usage node 20a likewise includes service area
10 information, access technique information, and the like. Then, the communication
control device 100 stores the information received fi"om the secondary usage node
20a in the storage unit 120 (step SI 10). The communication control device 100
transmits an acknowledgement signal (confirmation) confirming that the registration
has been finished to the secondary usage node 20a (step S112).
15 [0076]
Subsequently, the estimation unit 130 of the communication control device
100 estimates service areas of respective second communication services using the ^
service area information that has been received fi"om the respective secondary usage
nodes 20a and 20b (step SI 14). Here, the service area estimation process by the
:
20 estimation unit 130 may be performed after there is a request for an adjustment i
between the second communication services in step SI 16.
[0077]
• Next, when the necessity for an adjustment between the second
i
communication services is recognized, the secondary usage node 20a requests the
25 adjustment between the second communication services from the communication
control device 100 (step SI 16). Here, the secondary usage node may not request
the adjustment between the second communication services from the communication ]
control device 100, but rather, the communication control device 100 may
voluntarily start the adjustment between the second communication services.
30 Subsequently, the communication control device 100 determines a configviration of :
the second communication services to be recommended to the secondary usage node
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20a or another secondary usage node 20 (step SI 18). In the example of Fig. 10, the
other secondary usage node 20 corresponds to the secondary usage node 20b. The •
communication control device 100 notifies at least one of the secondary usage node
20a and the secondary usage node 20b of the recommended service configuration
5 (that is, a radio access technique to be used, a channel to be used, or the like) (step
SI 20).
[0078]
[3-2. Service Area Determination Process]
Fig. 11 is a flowchart showing an example of the flow of a service area
10 estimation process by the communication control device 100 in step SI 14 of Fig. 10.
[0079]
Referring to Fig. 11, first, the estimation unit 130 of the communication
control device 100 acquires a location, a maximum transmission power, and an
antenna height of the secondary usage node 20 stored in the storage unit 120 (step
15 SI32). Next, the estimation imit 130 calculates a radius of a service area of a
second communication service using the maximum transmission power and the
antenna height of the secondary usage node 20 (step SI34). The estimation unit
130 estimates that a circular area which has the radius calculated in step SI34
centered on the location of the secondary usage node 20 is the service area of the
20 second communication service provided by the secondary usage node 20 (step SI36).
When it is possible to acquire additional information, for example, data about the
antenna directivity of the secondary usage node 20, data of the surrounding terrain,
or the like, the estimation unit 130 may estimate a service area in an oval shape or a
more complex shape according to terrain, rather than a circular shape.
25 [0080]
[3-3. Process of Determining Recommended Service Configuration]
Fig. 12 to Fig. 14 are flowcharts showing an example of the flow of a
process of determining a recommended service configuration by the communication
control device 100 in step S118 of Fig. 10.
30 [0081] I
Referring to Fig. 12, first, the control unit 140 of the communication control
!
'•
!
i
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device 100 determines whether or not the service areas of the two second
communication services provided by the secondary usage nodes 20a and 20b overlap
(step S151). Whether or not the service areas overlap may be determined on the
I
basis of, for example, whether or not the sum of radii of the two service areas is less
5 than the distance between the secondary usage nodes 20a and 20b. Here, when it is
determined that the service areas do not overlap, the process proceeds to step S170 of
Fig. 14. On the other hand, when it is determined that the service areas overlap, the
process proceeds to step S152.
[0082]
10 When the process proceeds to step S152, a location relationship between the
service areas of the two second communication services belongs to any one of class
A, class B and class D shown in Fig. 5, Fig. 6 and Fig. 8. In this case, the control
unit 140 determines whether or not there is a common radio access technique that
can be used by the two secondary usage nodes 20a and 20b (step SI52). Here, 15 when it is determined that there is no common usable radio access technique, the
process proceeds to step SI 61 of Fig. 13. On the other hand, when it is determined
that there is a common usable radio access technique, the process proceeds to step
i
S153.
[0083]
20 In step S153, the control unit 140 determines whether or not a trigger for the
ongoing process of determining a recommended service configuration is a secondary
usage node (step SI53). For example, when the communication control device 100
has received a request for an adjustment between second communication services
from the secondary usage node 20a and thus the process of determining a
25 recommended service configuration has been started, it is determined that the trigger
i
for the process of determining a recommended service configuration is a secondary
usage node. In this case, the process proceeds to step SI61 of Fig. 13. On the
other hand, when the corrmiunication control device 100 has actively started the ;
process of determining a recommended service configuration, the trigger for the
30 process is not a secondary usage node, and thus the process proceeds to step SI54.
[0084]
SP306380WO00 ^ 33/48
In step SI54, the control unit 140 determines whether or not radio access
techniques that are currently being used by the two secondary usage nodes 20a and
20b are the same (step SI54). Here, when it is determined that the radio access
techniques that are currently being used are the same, the process proceeds to step
5 SI61 of Fig. 13. On the other hand, when it is determined that the radio access
techniques that are cvirrently being used are not the same, the process proceeds to ']
step SI55.
[0085] In step SI55, the control unit 140 determines whether or not the common
10 radio access techniques that are currently being used by the two secondary usage
nodes 20a and 20b operate validly (that is, in parallel without causing a problem)
(step SI55). For example, when radio access techniques in which it is difficult to
manage two systems in parallel are used in the situation in which the service areas
overlap, the control vmit 140 can determine that the common radio access techniques
15 do not validly operate. In this case, the process proceeds to step SI73 of Fig. 14.
On the other hand, when it is determined that the common radio access techniques
validly operate, the process proceeds to step SI56.
[0086]
When the process proceeds to step SI56, the control unit 140 recommends
20 that the two secondary usage nodes 20a and 20b use the common usable radio access
techniques and a common channel (step SI56). Also, the control unit 140
•
determines whether or not it is necessary to supply a synchronization signal to the
two secondary usage nodes 20a and 20b (step SI57). For example, when one
secondary usage node 20 is not included in a service area of the other secondary
25 usage node 20, the location relationship between the service areas of the two second
communication services corresponds to class B. In this case, when it is not possible
to use a mesh protocol stack, for example, Ecma392 and the like, it is necessary to
assist with synchronization between the communication services. In the case of
class A or class D also, when clock deviation is large like in the IEEE802.il family,
30 it is preferable to assist with synchronization between the communication services.
In such a situation, the control unit 140 can determine that it is necessary to supply a
I
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synchronization signal to the two secondary usage nodes 20a and 20b.
[0087]
When it is detennined in step SI57 that it is necessary to supply a
synchronization signal, the control unit 140 supplies a synchronization signal to the
5 two secondary usage nodes 20a and 20b through the communication unit 110 (step
SI58). On the other hand, when it is determined in step SI57 that it is unnecessary
to supply a synchronization signal, the communication control device 100 does not
supply a synchronization signal to these nodes.
[0088]
10 In step S161 of Fig. 13, the control unit 140 determines whether or not there
is a combination of radio access techniques that can be used by the two secondary
usage nodes 20a and 20b and can also coexist with each other on a common channel
in an overlapping service area (step SI61). For example, in a frame format of the
standard specification of IEEE802.22, a "Coexistence Beacon Period" for
15 exchanging information between a plurality of communication services is installed.
The secondary usage nodes 20a and 20b form a mesh network by exchanging
scheduling information, path information, or the like using, for example, the
"Coexistence Beacon Period," or exchange control information so that timings of
scheduling do not overlap, and thereby may cause the two commvmication services to
20 coexist. When it is determined that there is a combination of radio access techniques that can coexist, the control unit 140 recommends use of the radio access
techniques and a common channel (step S162). On the other hand, when there is no
combination of radio access techniques that can coexist, the process proceeds to step
S163. I
25 [0089]
•
In step SI63, the control unit 140 determines whether or not it is possible to
assign different channels to the two second communication services (step SI63).
Here, when it is possible to assign different chaimels to the two second
communication services, the control imit 140 recommends that the secondary usage
30 nodes 20a and 20b use the different channels (step SI64). For example, when
permissible channel information from the secondary usage nodes 20a and 20b
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;'
include the channels Fl and F2 in common, the channel Fl can be recommended to
the secondary usage node 20a, and the channel F2 can be recommended to the
secondary usage node 20b. On the other hand, when it is not possible to assign
different channels to the two second communication services, the process proceeds to [
5 step SI65.
[0090] ;:
In step SI65, the control unit 140 determines whether or not sharing of
communication resources becomes possible by supporting sharing of the
communication resources of the two second communication services (step SI65).
10 For example, when it is possible to cause the two communication services to coexist
in a time division method by supplying a synchronization signal to the secondary
usage nodes 20a and 20b, it can be determined that sharing of the communication i
resources is possible. In this case, the process proceeds to step SI67. On the other
hand, when it is determined that sharing of the communication resources is not
15 possible, the process proceeds to step SI66. In step S166, since no recommendable ,
combination is found, the control unit 140 notifies the secondary usage node 20a that
no recommendable combination is found.
[0091] :
In step SI67, the control unit 140 determines whether or not a service area |
20 of one second communication service is included in a service area of the other •
second communication service (step SI67). For example, when a difference in
radius between the two service areas is larger than a distance between the secondary
usage nodes 20a and 20b, it is possible to determine that a service area of one second
communication service is included in a service area of the other second
25 communication service. In this case, the process proceeds to step SI68. On the
other hand, when it is determined that a service area of one second commimication
service is not included in a service area of the other second communication service,
the process proceeds to step SI69. Here, even if it is determined that a service area
of one second communication service is not included in a service area of the other
30 second communication service, for example, when a ratio of the corresponding
portion does not exceed a predetermined value, the determination result of step S167
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can be "Yes."
[0092]
When the process proceeds to step SI68, the location relationship between
the service areas of the two second communication services belongs to class D
5 shown in Fig. 8. Also, communication resources can be shared. Such a
combination of radio access techniques includes, for example, a combination of
OFDMA and CSMA. For example, when a radio access technique of a second
communication service having a larger service area is OFDMA, communication
resources of the two second communication services can be shared by arranging the
10 communication resources as described with reference to Fig. 4. Here, the control
unit 140 implements sharing of communication resources by performing a process of
supporting sharing of communication resources exemplified in Fig. 15 (step SI 68).
[0093]
When the process proceeds to step S169, the location relationship between
15 the service areas of the two second communication services belongs to any one of
classes A and B shown in Fig. 5 and Fig. 6. Also, communication resources can be
shared. Even in this case, the control unit 140 implements sharing of
communication resources by performing the same process of supporting sharing of
communication resources as in the example of Fig. 15 (step SI 69).
20 [0094]
When the process proceeds to step SI 70 of Fig. 14, the location relationship
between the service areas of the two second communication services belongs to class
C shown in Fig. 7. In this case, the control unit 140 determines whether or not a
trigger for the ongoing process of determining a recommended service configuration
25 is a secondary usage node (step SI70). Here, when the trigger for the process of
determining a recommended service configuration is a secondary usage node, the
process proceeds to step SI72. On the other hand, when the trigger for the process
of determining a recommended service configuration is not a secondary usage node,
the process proceeds to step SI71. In step SI71, the control unit 140 determines
30 whether or not mutual interference between the nodes of the two second
communication services is an allowable level or less (step SI71). For example, the
.
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control unit 140 estimates an interference level between the two second i
communication services on the basis of transmission powers of the respective second i
communication services and path loss according to the distance between the nodes.
At this time, a margin for absorbing an estimation error may be included in the ;
5 estimation result of the interference level. Also, the control unit 140 compares the
estimated interference level with the allowable interference level according to
necessary communication quality (a minimum SINR and the like) of each secondary
communication service. On the basis of the results, the control unit 140 can ;
determine whether or not mutual interference between the nodes is the allowable
10 level. Alternatively, a node of a second communication service may measure an
actual interference level, and the communication control device 100 may receive the ;,
measurement result for comparison with the allowable interference level. Also, a
node of a second communication service may report a result of comparison between :
an actual interference level and the allowable interference level to the
15 communication control device 100. Here, when the mutual interference between
the nodes of the two second communication services does not exceed the allowable
level, the process proceeds to step SI72. In step SI72, the control unit 140
recommends that the secondary usage nodes 20a and 20b use a common channel
irrespective of radio access techniques. On the other hand, when the mutual
20 interference between the nodes of the two second communication services exceeds
the allowable level, the process proceeds to step S171. i
[0095]
In step SI73, the control unit 140 determines whether or not it is possible to
assign different channels to the two second communication services (step SI73).
25 Here, when it is possible to assign different channels to the two second j
communication services, the control unit 140 recommends that the secondary usage !
nodes 20a and 20b use the different channels (step SI74). On the other hand, when
it is not possible to assign different channels to the two second commimication
services, the process proceeds to step S175.
30 [0096]
In step SI75, the control unit 140 determines whether or not sharing of
:
I
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i
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;
communication resources becomes possible by supporting sharing of the
communication resources of the two second communication services (step SI75).
Here, when it is determined that sharing of the communication resources is possible,
the process proceeds to step SI77. On the other hand, when it is determined that
5 sharing of the commvmication resources is not possible, the process proceeds to step
SI76. In step SI76, since no reconmiendable combination is found, the control unit
140 notifies the secondary usage node 20a that no recommendable combination is •
fovmd. [0097] •
10 In step SI77, the control unit 140 implements sharing of commxmication
resources by performing the same process of supporting sharing of communication
resources as the example of Fig. 15 (step SI 77).
[0098] ;
The flow of the process of determining a recommended service
15 configuration by the communication control device 100 is not limited to the example
shown in Fig. 12 to Fig. 14. In other words, some process steps shown in Fig. 12 to
Fig. 14 may be omitted or integrated, or additional steps may be added. Also, the
sequence of process steps may be changed. Here, an example in which the
communication control device 100 adjusts a service configuration between two
:
20 communication services has been mainly described. However, this embodiment can
'••
also be applied to the case of an adjustment among three or more communication
services in the same way r
[0099]
[3-4. Process of Supporting Sharing of Communication Resources]
25 Fig. 15 is a flowchart showing an example of the flow of a process of
supporting sharing of communication resources among the communication control ;
device 100 and the secondary usage nodes 20a and 20b in the case of class D in step
SI68 of Fig. 13. Processes of supporting sharing of communication resources for
other classes can also be the same as in the following example.
30 [0100]
Referring to Fig. 15, flrst, the communication control device 100 requests
I
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sharing of communication resources from the secondary usage node 20b that
provides a second communication service having a larger service area (step S202).
TTiis request demands provision of shared resource information that specifies a range
of sharable communication resources. Then, the secondary usage node 20b
5 determines sharable communication resources according to a traffic situation, and
responds with the shared communication resources (step S204). Next, the
communication control device 100 transmits the shared resource information
received from the secondary usage node 20b to the secondary usage node 20a (step
i'
S206). Then, the secondary usage node 20a confirms that sharing of |
10 communication resources is possible, and transmits an acknowledgement to the i
i
communication control device 100 (step S208). The communication control device '
100 supplies a synchronization signal to the secondary usage nodes 20a and 20b (step
E
S210). Subsequently, the secondary usage node 20a manages a second-order
second communication service using communication resources within the range
15 specified by the shared resource information without the second-order second S
communication service and a first-order second communication service causing '
interference with each other.
[0101] •
In addition, for example, in step S206 or step S210, the commimication
20 control device 100 may transmit additional control information for preventing
interference caused by sharing communication resources to the secondary usage node
20a. The additional control information can include, for example, information such
as a maximum transmission power level allowed to the secondary usage node 20a, a ;
new spectrum mask, a transmission power adjustment value for a child node of the I
25 secondary usage node 20a, and the like
[0102]
<4. Summarization>
Thus far, one embodiment of the present disclosure has been described with
reference to Fig. 1 to Fig. 15. In the above-described embodiment, when at least a
30 portion of a service area of a second-order second communication service is included
in a service area of a first-order second communication service, the communication
•
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control device 100 determines whether or not sharing of communication resources is
possible on the basis of radio access techniques of the first-order second
communication service and the second-order second communication service.
According to such a configuration, even when there are a plurality of secondary
5 usage nodes that each want secondary usage, and service areas and permitted
channels of the secondary usage nodes overlap, it is possible to improve efficiency in
frequency usage or increase opportunities for secondary usage by causing
communication resources to be shared.
[0103]
10 In addition, in this embodiment, when a radio access technique of a second
communication service having a larger service area is OFDMA, the communication
control device 100 determines that sharing of communication resources is possible.
In this case, using a scheduling method of the secondary usage node (for example, a
base station for the second communication service) that employs OFDMA,
15 communication resources can be flexibly shared in units of scheduling such as
resource blocks or the like. Additionally, when a radio access technique of a second
communication service having a smaller service area is CSMA, the communication
control device 100 may determine that sharing of communication resources is
possible. In this case, a terminal device of the second-order second communication
20 service that employs CSMA can perform communication according to a timing in a
section of communication resources distributed from the first-order second
commvmication service in a predetermined collision avoidance (or collision
detection) sequence.
[0104]
25 Furthermore, in this embodiment, the commimication control device 100
can determine whether or not sharing of communication resources is possible in
response to a request from a secondary usage node that provides a second
communication service, and thus opportimities for secondary usage can be given to a
larger number of secondary usage nodes. In particular, when a frequency band is
30 secondarily used, there are many cases in which it is not found in advance what kind
of radio access technique each secondary usage node supports. Also, to give each
j [
[
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secondary usage node a function for performing an adjustment between second ,
communication services is not practical in terms of cost, and makes it difficult to
ensure neutrality of the adjustment. Accordingly, provision of the neutral
communication control device 100 that collects information about each secondary
5 usage node such as a radio access technique, and the like and performs an adjustment
between second communication services is useful in terms of cost and also neutrality
of the adjustment.
[0105]
In addition, a control process of the communication control device 100 and
10 the secondary usage nodes 20 described in this specification can be implemented
using software. Programs constituting the software that implements the
aforementioned control process are contained in advance on a storage medium
installed in or outside each device. Each program is read, for example, by a
Random Access Memory (RAM) upon execution and executed by a processor such
15 as a Central Processing Unit (CPU) or the like.
[0106]
The preferred embodiments of the present invention have been described
above with reference to the accompanying drawings, whilst the present invention is
not limited to the above examples, of course. A person skilled in the art may find
20 various alternations and modifications within the scope of the appended claims, and
it should be understood that they will naturally come under the technical scope of the I
present invention. I
Reference Signs List
25 [0107]
10 Primary usage node
20 Secondary usage node
40 Data server
100 Communication control device
30 110 Communication unit (communication control device)
120 Storage xmit (communication control device)
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I-;
130 Estimation unit (communication control device)
140 Control unit (communication control device)
210 First communication unit (secondary usage node)
220 Second communication unit (secondary usage node)
5 230 Storage unit (secondary usage node)
240 Secondary usage control unit (secondary usage node)
;
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CLAIMS
Claim 1
A communication control device which controls communication of one or
more secondary usage nodes respectively providing second communication services
5 using a part of a frequency band assigned to a first communication service, the
communication control device comprising:
a communication unit that receives access technique information indicating
radio access techniques usable by the corresponding secondary usage nodes from the
respective secondary usage nodes;
10 a storage unit that stores the access technique information received by the
communication unit; and
a control unit that, when at least a portion of a service area of a second-order
second communication service is included in a service area of a first-order second
communication service, determines whether or not at least a part of communication
15 resources can be shared between the first-order second communication service and
the second-order second communication service on the basis of the radio access
techniques of the first-order second communication service and the second-order
second communication service indicated by the access technique information.
20 Claim 2
The communication control device according to claim 1,
wherein, if the service area of the second-order second communication
service is not included in the service area of the first-order second communication
service, even when a level of mutual interference between the first-order second
25 communication service and the second-order second communication service exceeds
an allowable interference level, the control unit determines whether or not a part of
the communication resources can be shared between the first-order second
communication service and the second-order second communication service.
30 Claim 3
The communication control device according to claim 1,
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wherein, when a radio access technique indicated by the access technique
information corresponding to the first-order second communication service is
OFDMA, the control unit determines that a part of the commxmication resources can
be shared.
5
Claim 4
The communication control device according to claim 1,
wherein, when a radio access technique indicated by the access technique
information corresponding to the first-order second communication service is
10 OFDMA, and a radio access technique indicated by the access technique information
corresponding to the second-order second communication service is CSMA, the
control unit determines that a part of the communication resources can be shared.
Claim 5
15 The communication control device according to claim 1,
wherein the control unit determines whether or not a part of the
communication resources can be shared in response to a request from a secondary
usage node providing the second-order second communication service.
20 Claim 6
The communication control device according to claim 1,
wherein, when it is determined that a part of the communication resources
can be shared, the control unit requests a secondary usage node providing the firstorder
second communication service to provide information specifying a range of
25 sharable communication resources.
Claim 7
The communication control device according to claim 6,
wherein the control unit provides the information specifying the range of
30 sharable communication resources received fi-om the secondary usage node
providing the first-order second communication service to a secondary usage node
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providing the second-order second communication service.
Claim 8
The communication control device according to claim 6,
5 wherein, when there are sharable communication resources, the control unit
supplies a synchronization signal to the secondary usage nodes respectively
providing the first-order second communication service and the second-order second
communication service.
10 Claim 9
The communication control device according to claim 6,
wherein, when there are sharable communication resources, the control unit
transmits control information for preventing interference caused by sharing the
communication resources to a secondary usage node providing the second-order
15 second communication service.
Claim 10
The communication control device according to claim 1, further comprising:
an estimation unit that estimates a service area of the first-order second
20 communication service and a service area of the second-order second communication
service using service area information for estimating the service areas of the second
commimication services provided by the secondary usage nodes,
wherein the communication unit fiirther receives the service area
information fi-om the respective secondary usage nodes.
25
Claim 11
The communication control device according to claim 1,
wherein, when no portion of the service area of the second-order second
communication service is included in the service area of the first-order second
30 communication service, the control unit reduces the service area of the second-order
second communication service in order to share the communication resources.
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Claim 12
A communication control method for controlling communication of a
plurality of secondary usage nodes respectively providing second communication
5 services using a part of a frequency band assigned to a first communication service,
the conmiunication control method comprising:
receiving access technique information indicating radio access techniques
usable by the corresponding secondary usage nodes from the respective secondary
usage nodes;
10 storing the received access technique information; and
when at least a portion of a service area of a second-order second
communication service is included in a service area of a first-order second
communication service, determining whether or not at least a part of communication
resources can be shared between the first-order second communication service and
15 the second-order second communication service on the basis of the radio access
techniques of the first-order and second-order second communication services
indicated by the access technique information.
Claim 13
20 A communication system which includes a plurality of secondary usage
nodes respectively providing second commvinication services using a part of a
frequency band assigned to a first communication service and a communication
control device controlling communication of the plurality of secondary usage nodes,
wherein each of the secondary usage nodes includes:
25 a communication unit that fransmits access technique information indicating
radio access techniques usable by the corresponding secondary usage nodes to the
communication control device, and
wherein the commimication control device includes:
a communication unit that receives the access technique information from
30 the respective secondary usage nodes;
a storage unit that stores the access technique information received by the
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communication unit; and
a control unit that, when at least a portion of a service area of a second-order
second communication service is included in a service area of a first-order second
communication service, determines whether or not at least a part of communication
5 resources can be shared between the first-order second communication service and
the second-order second communication service on the basis of the radio access
techniques of the first-order second communication service and the second-order
second communication service indicated by the access technique information.
10 Claim 14 "^'^
A communication device which provides a second communication service
using a part of a fi*equency band assigned to a first communication service, the
communication device comprising:
a communication unit that transmits access technique information indicating
15 a radio access technique usable by the communication device to another device in
order to cause the other device to determine whether or not it is necessary to share a
part of communication resources of the second communication service with another
second communication service; and
a secondary usage control unit that specifies a range of communication
20 resources sharable with the other second communication service in response to a ^
request from the other device when the other device determines that a service area of
the second communication service includes a service area of the other second
communication service, and it is necessary to share a part of the communication
resources of the second communication service on the basis of the access technique
25 information.