Title of Invention: DEVICE
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Japanese Priority Patent Application JP
2014-154714 filed July 30, 2014, the entire contents of which are incorporated herein
by reference.
Technical Field
[0002] The present disclosure relates to a device.
Background Art
[0003] Device-to-device communication (D2D communication) is communication in which
two or more terminal devices transmit and receive signals directly, unlike typical
cellular communication in which a base station and a terminal device transmit and
receive signals. For this reason, it is anticipated that D2D communication will be used
to create new usage scenarios for terminal devices that differ from the typical cellular
communication above. For example, various applications are conceivable, such as information
sharing by data communication between nearby terminal devices or among a
group of nearby terminal devices, distribution of information from an installed terminal
device, and autonomous communication between machines, called machineto-
machine (M2M) communication.
[0004] Additionally, it is conceivable that D2D communication will be put to effective use
in data offloading in response to the significant increase in data traffic due to the recent
increase in smartphones. For example, in recent years, there has been a sharp rise in the
necessity to transmit and receive video image streaming data. However, since video
images typically have large data sizes, there is a problem of consuming many resources
on a radio access network (RAN). Consequently, if terminal devices are in a state
suitable for D2D communication with each other, such as when the terminal devices
are a short distance away from each other, video image data may be offloaded to D2D
communication, thereby moderating the resource consumption and processing load on
a RAN. In this way, D2D communication provides value to both telecommunications
carriers and users. For this reason, D2D communication is currently recognized as one
crucial technology area for Long Term Evolution (LTE), and is receiving attention
from the 3rd Generation Partnership Project (3GPP) standards committee.
[0005] For example, Non Patent Literature 1 discloses technology such as synchronization
and discovery of D2D communication.
Citation List
Non Patent Literature
2
WO 2016/017099 PCT/JP2015/003566
[0006] [NPL 1] 3GPP TR 36.843 V12.0.0 (March 2014)
Summary
Technical Problem
[0007] In Non Patent Literature 1, a method of a terminal device recognizing radio resources
available for D2D communication is not disclosed.
[0008] For example, radio resources (a resource pool) available for D2D communication are
selected by a base station in the case of in-coverage and is selected by a representative
terminal device in the case of out-of-coverage.
[0009] In the case of in-coverage, the base station may notify the terminal device of the
radio resources available for D2D communication. However, when the base station
freely selects the radio resources available for D2D communication without constraints,
the base station may use many radio resources in order to notify the radio
resources available for D2D communication. As a result, from the viewpoint of the
radio resources, a load on the base station may become large.
[0010] In the case of out-of-coverage, the representative terminal device may notify another
terminal device of the radio resources available for D2D communication. However,
since the other terminal device does not recognize radio resources that are used by the
representative terminal device to notify the radio resources available for D2D communication,
a trial and error search (for example, a synchronization signal and/or synchronization
information (information of synchronization) is detected by trial and error)
may be performed. As a result, a load on the other terminal device may become large.
In addition, similar to the case of in-coverage, in the case of out-of-coverage, from the
viewpoint of the radio resources, a load on the representative terminal device may
become large.
[0011] Therefore, it is preferable to provide a mechanism in which a load necessary for a
terminal device to recognize the radio resources available for D2D communication can
be reduced.
Solution to Problem
[0012] According to an exemplary embodiment of the present disclosure, there is provided a
device including: an acquisition unit configured to acquire information indicating one
or more resource pools serving as radio resources available for device-to-device communication;
and a control unit configured to notify a terminal device of the one or
more resource pools. The one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource pools, which are
determined in advance as candidates for radio resources available for device-to-device
communication.
[0013] According to another exemplary embodiment of the present disclosure, there is
3
WO 2016/017099 PCT/JP2015/003566
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to control device-to-device
communication by a terminal device in at least one resource pool among the one or
more resource pools. The one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource pools, which are
determined in advance as candidates for radio resources available for device-to-device
communication.
[0014] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the one or more resource pools in a predetermined resource pool.
[0015] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication from information received by a terminal device in a predetermined
resource pool; and a control unit configured to control device-to-device communication
by the terminal device in at least one resource pool among the one or more
resource pools.
[0016] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the change in a primary resource pool among one or more resource pools serving as
radio resources available for device-to-device communication.
[0017] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication from information received by a terminal device in a primary
resource pool among one or more resource pools serving as radio resources available
for device-to-device communication; and a control unit configured to control deviceto-
device communication by the terminal device in at least one resource pool in accordance
with the change.
[0018] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication; and a control unit configured to notify a terminal device of
4
WO 2016/017099 PCT/JP2015/003566
the change by at least one of reporting of system information indicating the change and
separate signaling.
[0019] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an in-coverage resource pool serving as a radio resource available for deviceto-
device communication within a network coverage area and an out-of-coverage
resource pool serving as a radio resource available for device-to-device communication
outside of the network coverage area; and a control unit configured to control deviceto-
device communication by a terminal device in a manner that the terminal device
transmits a signal of device-to-device communication in both of the in-coverage
resource pool and the out-of-coverage resource pool when received power in the
terminal device of a signal transmitted by a base station is less than first power and is
greater than second power which is less than the first power.
[0020] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an in-coverage resource pool serving as a radio resource available for deviceto-
device communication within a network coverage area and an out-of-coverage
resource pool serving as a radio resource available for device-to-device communication
outside of the network coverage area; and a control unit configured to notify a terminal
device of the in-coverage resource pool and the out-of-coverage resource pool.
[0021] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a resource pool group that is used by a synchronized terminal device and
includes one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the resource pool group.
[0022] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a resource pool group that is used by a synchronized terminal device and
includes one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to control device-to-device
communication by a terminal device in a manner that the terminal device omits synchronization
based on a synchronization signal transmitted in at least one resource pool
included in the resource pool group.
[0023] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an application of device-to-device communication that is performed in each of
one or more resource pools serving as radio resources available for device-to-device
5
WO 2016/017099 PCT/JP2015/003566
communication; and a control unit configured to notify a terminal device of the application.
[0024] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an application of device-to-device communication that is performed in each of
one or more resource pools serving as radio resources available for device-to-device
communication; and a control unit configured to control device-to-device communication
by a terminal device in a manner that the terminal device performs deviceto-
device communication in a desired application in a resource pool in which deviceto-
device communication is performed in the desired application among the one or
more resource pools.
[0025] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a desired application of device-to-device communication of a terminal device;
and a control unit configured to notify the terminal device of one or more resource
pools in which device-to-device communication is performed in the desired application
and which are one or more resource pools serving as radio resources available for
device-to-device communication.
[0026] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a desired application of device-to-device communication of a terminal device;
and
a control unit configured to notify a base station or another terminal device of the
desired application. The control unit controls device-to-device communication in the
desired application by the terminal device in at least one resource pool among one or
more resource pools of which the base station or the other terminal device notifies the
terminal device. The one or more resource pools are radio resources available for
device-to-device communication and are resource pools in which device-to-device
communication is performed in the desired application.
[0027] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
the number of terminal devices configured to perform device-to-device communication;
and a control unit configured to select a resource pool serving as a radio
resource available for device-to-device communication based on the number of
terminal devices configured to perform device-to-device communication. The control
unit notifies the terminal device of the resource pool.
[0028] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information in6
WO 2016/017099 PCT/JP2015/003566
dicating a transmission resource pool serving as a radio resource available for
transmission in device-to-device communication and a retransmission resource pool
serving as a radio resource available for retransmission in device-to-device communication;
and a control unit configured to notify a terminal device of the transmission
resource pool and the retransmission resource pool.
[0029] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a transmission resource pool serving as a radio resource available for
transmission in device-to-device communication and a retransmission resource pool
serving as a radio resource available for retransmission in device-to-device communication;
and a control unit configured to control device-to-device communication of a
terminal device in a manner that the terminal device performs transmission in the
transmission resource pool in device-to-device communication and the terminal device
performs retransmission in the retransmission resource pool in device-to-device communication.
[0030] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an audio resource pool serving as a radio resource available for transmitting
audio data in device-to-device communication and another resource pool serving as a
radio resource available for transmitting another data in device-to-device communication;
and a control unit configured to notify a terminal device of the audio resource
pool and the another resource pool.
[0031] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an audio resource pool serving as a radio resource available for transmitting
audio data in device-to-device communication and another resource pool serving as a
radio resource available for transmitting another data in device-to-device communication;
and a control unit configured to control device-to-device communication of a
terminal device in a manner that the terminal device transmits audio data in the audio
resource pool in device-to-device communication and the terminal device transmits
another data in the another resource pool in device-to-device communication.
[0032] According to another exemplary embodiment of the present disclosure, a device
includes circuitry configured that acquires information indicating one or more resource
pools serving as radio resources available for device-to-device communication, and
that notifies a terminal device of the one or more resource pools,
wherein the one or more resource pools are resource pools that are selected from
among a resource pool set including multiple resource pools. The multiple resource
pools are determined in advance as candidates for radio resources available for device7
WO 2016/017099 PCT/JP2015/003566
to-device communication.
[0033] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating one or more resource pools
serving as radio resources available for device-to-device communication, and that
controls device-to-device communication by a terminal device in at least one resource
pool among the one or more resource pools. The one or more resource pools are
resource pools that are selected from among a resource pool set including multiple
resource pools, which are determined in advance as candidates for radio resources
available for device-to-device communication.
[0034] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating one or more resource pools
serving as radio resources available for device-to-device communication, and notifies a
terminal device of the one or more resource pools in a predetermined resource pool.
[0035] According to another exemplary aspect of the present disclosure, a device includes
circuitry that acquires information indicating one or more resource pools serving as
radio resources available for device-to-device communication from information
received by a terminal device in a predetermined resource pool, and controls deviceto-
device communication by the terminal device in at least one resource pool among
the one or more resource pools.
[0036] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication, and notifies
a terminal device of the change in a primary resource pool among one or more
resource pools serving as radio resources available for device-to-device communication.
[0037] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication from information
received by a terminal device in a primary resource pool among one or more
resource pools serving as radio resources available for device-to-device communication,
and controls device-to-device communication by the terminal device in at
least one resource pool in accordance with the change.
[0038] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication, and notifies
a terminal device of the change by at least one of reporting of system information indicating
the change and separate signaling.
[0039] According to another exemplary embodiment of the present disclosure, a device
8
WO 2016/017099 PCT/JP2015/003566
includes circuitry that acquires information indicating an in-coverage resource pool
serving as a radio resource available for device-to-device communication within a
network coverage area and an out-of-coverage resource pool serving as a radio
resource available for device-to-device communication outside of the network
coverage area.
[0040] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an in-coverage resource pool
serving as a radio resource available for device-to-device communication within a
network coverage area and an out-of-coverage resource pool serving as a radio
resource available for device-to-device communication outside of the network
coverage area, and notifies a terminal device of the in-coverage resource pool and the
out-of-coverage resource pool.
[0041] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a resource pool group that is
used by a synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication, and notifies a
terminal device of the resource pool group.
[0042] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a resource pool group that is
used by a synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication, and controls
device-to-device communication by a terminal device in a manner that the terminal
device omits synchronization based on synchronization information transmitted in at
least one resource pool included in the resource pool group.
[0043] According to another exemplary embodiment, a device includes circuitry that
acquires information indicating an application of device-to-device communication that
is performed in each of one or more resource pools serving as radio resources available
for device-to-device communication, and notifies a terminal device of the application.
[0044] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an application of deviceto-
device communication that is performed in each of one or more resource pools
serving as radio resources available for device-to-device communication; and controls
device-to-device communication by a terminal device in a manner that the terminal
device performs device-to-device communication in a desired application in a resource
pool in which device-to-device communication is performed in the desired application
among the one or more resource pools.
[0045] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a desired application of device9
WO 2016/017099 PCT/JP2015/003566
to-device communication of a terminal device, and notifies the terminal device of one
or more resource pools in which device-to-device communication is performed in the
desired application and which are one or more resource pools serving as radio
resources available for device-to-device communication.
[0046] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a desired application of deviceto-
device communication of a terminal device, notifies a base station or another
terminal device of the desired application, and controls device-to-device communication
in the desired application by the terminal device in at least one resource pool
among one or more resource pools of which the base station or the other terminal
device notifies the terminal device. The one or more resource pools are radio resources
available for device-to-device communication and are resource pools in which deviceto-
device communication is performed in the desired application.
[0047] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating the number of terminal devices
configured to perform device-to-device communication, selects a resource pool serving
as a radio resource available for device-to-device communication based on the number
of terminal devices configured to perform device-to-device communication, and
notifies the terminal device of the resource pool.
[0048] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a transmission resource pool
serving as a radio resource available for transmission in device-to-device communication
and a retransmission resource pool serving as a radio resource available for retransmission
in device-to-device communication, and notifies a terminal device of the
transmission resource pool and the retransmission resource pool.
[0049] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a transmission resource pool
serving as a radio resource available for transmission in device-to-device communication
and a retransmission resource pool serving as a radio resource available for retransmission
in device-to-device communication, and that controls device-to-device
communication of a terminal device in a manner that the terminal device performs
transmission in the transmission resource pool in device-to-device communication and
the terminal device performs retransmission in the retransmission resource pool in
device-to-device communication.
[0050] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an audio resource pool serving
as a radio resource available for transmitting audio data in device-to-device communication
and another resource pool serving as a radio resource available for
10
WO 2016/017099 PCT/JP2015/003566
transmitting another data in device-to-device communication, and notifies a terminal
device of the audio resource pool and the another resource pool.
[0051] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an audio resource pool serving
as a radio resource available for transmitting audio data in device-to-device communication
and another resource pool serving as a radio resource available for
transmitting another data in device-to-device communication, and that controls deviceto-
device communication of a terminal device in a manner that the terminal device
transmits audio data in the audio resource pool in device-to-device communication and
the terminal device transmits another data in the another resource pool in deviceto-
device communication.
Advantageous Effects of Invention
[0052] According to one or more of embodiments of the present disclosure described above,
it is possible to reduce a load necessary for a terminal device to recognize the radio
resources available for D2D communication. Also, the above effects are not necessarily
limited, but along with the effects or instead of the effects, any effect shown in
this specification or other effects that may be understood from this specification may
be achieved.
Brief Description of Drawings
[0053] [fig.l]FIG. 1 is a first explanatory diagram illustrating a specific example of a use case
of D2D communication.
[fig.2]FIG. 2 is a second explanatory diagram illustrating a specific example of a use
case of D2D communication.
[fig.3]FIG. 3 is an explanatory diagram illustrating exemplary timings of a PSS and an
SSS in FDD.
[fig.4]FIG. 4 is an explanatory diagram illustrating exemplary timings of a PSS and an
SSS in TDD.
[fig.5]FIG. 5 is an explanatory diagram illustrating a radio frame and subframes in a
cellular system.
[fig.6]FIG. 6 is an explanatory diagram illustrating an exemplary resource pool.
[fig.7]FIG. 7 is an explanatory diagram illustrating an example of a signal and information
transmitted in a resource pool.
[fig.8]FIG. 8 is an explanatory diagram illustrating an example of a schematic configuration
of a communication system according to an embodiment of the present
disclosure.
[fig.9]FIG. 9 is a block diagram illustrating an exemplary configuration of a base
station according to the embodiment.
11
WO 2016/017099 PCT/JP2015/003566
[fig. 10] FIG. 10 is a block diagram illustrating an exemplary configuration of a first
terminal device according to the embodiment.
[fig. 11]FIG. 11 is a block diagram illustrating an exemplary configuration of a second
terminal device according to the embodiment.
[fig.l2]FIG. 12 is an explanatory diagram illustrating an exemplary resource pool set.
[fig.l3]FIG. 13 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a first embodiment.
[fig.l4]FIG. 14 is a sequence diagram schematically illustrating a first exemplary flow
of a second process according to the first embodiment.
[fig.l5]FIG. 15 is a sequence diagram schematically illustrating a second exemplary
flow of a second process according to the first embodiment.
[fig.l6]FIG. 16 is a sequence diagram schematically illustrating an exemplary flow of
a process according to a second embodiment.
[fig.l7]FIG. 17 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a third embodiment.
[fig.l8]FIG. 18 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the third embodiment.
[fig.l9]FIG. 19 is a sequence diagram schematically illustrating an exemplary flow of
a third process according to the third embodiment.
[fig.20]FIG. 20 is a flowchart schematically illustrating an exemplary flow of a process
according to a fourth embodiment.
[fig.21]FIG. 21 is an explanatory diagram illustrating a first example of a resource pool
group.
[fig.22]FIG. 22 is an explanatory diagram illustrating a second example of a resource
pool group.
[fig.23]FIG. 23 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a fifth embodiment.
[fig.24]FIG. 24 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the fifth embodiment.
[fig.25]FIG. 25 is an explanatory diagram illustrating an exemplary application of D2D
communication performed in each resource pool.
[fig.26]FIG. 26 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a sixth embodiment.
[fig.27]FIG. 27 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the sixth embodiment.
[fig.28]FIG. 28 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a seventh embodiment.
[fig.29]FIG. 29 is a sequence diagram schematically illustrating an exemplary flow of
12
WO 2016/017099 PCT/JP2015/003566
a second process according to the seventh embodiment.
[fig. 30] FIG. 30 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to an eighth embodiment.
[fig.31]FIG. 31 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the eighth embodiment.
[fig. 32] FIG. 32 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a ninth embodiment.
[fig.33]FIG. 33 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the ninth embodiment.
[fig. 34] FIG. 34 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a tenth embodiment.
[fig.35]FIG. 35 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the tenth embodiment.
[fig.36]FIG. 36 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to an eleventh embodiment.
[fig.37]FIG. 37 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the eleventh embodiment.
[fig.38]FIG. 38 is a block diagram illustrating a first example of a schematic configuration
of an eNB.
[fig. 39] FIG. 39 is a block diagram illustrating a second example of a schematic configuration
of an eNB.
[fig.40]FIG. 40 is a block diagram illustrating an example of a schematic configuration
of a smartphone.
[fig.41]FIG. 41 is a block diagram illustrating an example of a schematic configuration
of a car navigation device.
Description of Embodiments
[0054] Hereinafter, preferred embodiments of the present disclosure will be described in
detail with reference to the appended drawings. Note that, in this specification and the
appended drawings, structural elements that have substantially the same function and
structure are denoted with the same reference numerals, and repeated explanation of
these structural elements is omitted.
[0055] Also, in this specification and the appended drawings, elements having substantially
the same function and structure may in some cases be distinguished by different letters
appended to the same sign. For example, multiple elements having substantially the
same function and structure are distinguished as terminal devices 10A, 10B, 10C, and
so on as appropriate. On the other hand, when not particularly distinguishing each of
multiple elements having substantially the same function and structure, only the same
13
WO 2016/017099 PCT/JP2015/003566
sign will be given. For example, the terminal devices 10A, 10B, IOC will be simply
designated the terminal device 10 when not being particularly distinguished.
[0056] Hereinafter, the description will proceed in the following order.
1. Introduction
2. Schematic Configuration of Communication System
3. Configuration of Respective Devices
3.1. Base Station Configuration
3.2. First Terminal Device Configuration
3.2. Second Terminal Device Configuration
4. First Embodiment
4.1 Outline
4.2 Operation of Base Station
4.3 Operation of First Terminal Device
4.4 Operation of Second Terminal Device
4.5 Process Flow
5. Second Embodiment
5.1 Outline
5.2 Operation of First Terminal Device
5.3 Operation of Second Terminal Device
5.4 Process Flow
6. Third Embodiment
6.1 Outline
6.2 Operation of First Terminal Device
6.3 Operation of Second Terminal Device
6.4 Operation of Base Station
6.5 Process Flow
7. Fourth Embodiment
7.1 Outline
7.2 Operation of Base Station
7.3 Operation of First Terminal Device
7.4 Operation of Second Terminal Device
7.5 Process Flow
8. Fifth Embodiment
8.1 Outline
8.2 Operation of Base Station
8.3 Operation of First Terminal Device
8.4 Operation of Second Terminal Device
8.5 Process Flow
14
WO 2016/017099 PCT/JP2015/003566
9. Sixth Embodiment
9.1 Outline
9.2 Operation of Base Station
9.3 Operation of First Terminal Device
9.4 Operation of Second Terminal Device
9.5 Process Flow
10. Seventh Embodiment
10.1 Outline
10.2 Operation of Base Station
10.3 Operation of First Terminal Device
10.4 Operation of Second Terminal Device
10.5 Process Flow
11. Eighth Embodiment
11.1 Outline
11.2 Operation of Base Station
11.3 Operation of First Terminal Device
11.4 Process Flow
12. Ninth Embodiment
12.1 Outline
12.2 Operation of Base Station
12.3 Operation of First Terminal Device
12.4 Process Flow
13. Tenth Embodiment
13.1 Outline
13.2 Operation of Base Station
13.3 Operation of First Terminal Device
13.4 Operation of Second Terminal Device
13.5 Process Flow
14. Eleventh Embodiment
14.1 Outline
14.2 Operation of Base Station
14.3 Operation of First Terminal Device
14.4 Operation of Second Terminal Device
14.5 Process Flow
15. Combination of Embodiments
16. Applications
16.1 Applications related to Base Station
16.2 Applications related to Terminal Device
15
WO 2016/017099 PCT/JP2015/003566
17. Conclusion
[0057] « 1 . Introduction»
First, technology related to D2D communication will be described with reference to
FIGS. 1 to 7.
[0058] (Use case of D2D communication)
In general LTE systems, an evolved Node B (eNB) and a user equipment (UE)
perform radio communication, but UEs do not perform radio communication to each
other. However, a method in which the UEs directly perform radio communication to
each other is necessary for an application for public safety (for example, an application
such as collision avoidance) or data offloading.
[0059] Use cases of D2D communication are discussed in 3GPP service and systems aspects
(SA) 1 and the like, and are described in TR 22.803. Also, in TR 22.803, use cases are
disclosed, but specific implementation methods are not disclosed. Hereinafter, specific
examples of the use case will be described with reference to FIGS. 1 and 2.
[0060] FIG. 1 is a first explanatory diagram illustrating a specific example of a use case of
D2D communication. Referring to FIG. 1, multiple UEs 10 and an eNB 20 are illustrated.
As a first use case, for example, an UE 10A and an UE 10B positioned
within a network coverage area (for example, inside a cell 21 of the eNB 20) perform
D2D communication. Such D2D communication is referred to as in-coverage D2D
communication. As a second use case, for example, an UE 10C and an UE 10D positioned
outside of the network coverage area perform D2D communication. Such D2D
communication is referred to as out-of-coverage D2D communication. As a third use
case, for example, an UE 10E positioned within the network coverage area and an UE
10F positioned outside of the network coverage area perform D2D communication.
Such D2D communication is referred to as partial-coverage D2D communication.
From the viewpoint of public safety, out-of-coverage D2D communication and partialcoverage
D2D communication are also important. Also, the network coverage area
refers to a coverage area of a cellular network. That is, a set of cells builds the network
coverage area.
[0061] FIG. 2 is a second explanatory diagram illustrating a specific example of a use case
of D2D communication. Referring to FIG. 2, an UE 10A and an UE 10B, and an eNB
20A and an eNB 20B are illustrated. In this example, the eNB 20A is operated by a
first mobile network operator (MNO) and the eNB 20B is operated by a second MNO.
Then, the UE 10A positioned within a first network coverage area (for example, inside
a cell 21A of the eNB 20A) and the UE 10B positioned within a second network
coverage area (for example, inside a cell 2IB of the eNB 20B) perform D2D communication.
From the viewpoint of public safety, such D2D communication is also
important.
16
WO 2016/017099 PCT/JP2015/003566
[0062] (Flow up to D2D communication)
For example, synchronization, discovery, and connection establishment are sequentially
performed, and then D2D communication is performed. Hereinafter, considerations
of steps of synchronization, discovery, and connection establishment will be
described.
[0063] (a) Synchronization
When two UEs are positioned within the network coverage area, the two UEs obtain
synchronization with the eNB using a downlink signal from the eNB and thus are able
to be synchronized to each other to some extent.
[0064] On the other hand, when at least one of two UEs attempting to perform D2D communication
is positioned outside of the network coverage area, at least one of the two UEs
is necessary to transmit a synchronization signal for synchronization in D2D communication.
[0065] (b) Discovery of other UEs
Discovery of other UEs is performed by, for example, transmitting and receiving a
discovery signal. More specifically, for example, one UE of the two UEs transmits the
discovery signal, and the other UE of the two UEs receives the discovery signal and
attempts to communicate with the one UE.
[0066] The discovery signal is preferably transmitted at a predetermined timing in a time
direction. Accordingly, it is possible to restrict a timing at which the UE of a reception
side attempts to receive the discovery signal. Also, as the assumption, two UEs attempting
to perform D2D communication may obtain synchronization in advance
before the discovery signal is received.
[0067] (c) Connection establishment
The two UEs attempting to perform D2D communication may establish a connection,
for example, as follows. First, a first UE transmits a discovery signal and a second UE
receives the discovery signal. Then, the second UE transmits a request message requesting
connection establishment to the first UE. Then, the first UE transmits a
completion message indicating completion of connection establishment to the second
UE in response to the request message.
[0068] (Synchronization signal transmitted by eNB)
In LTE, the eNB transmits a primary synchronization signal (PSS) and a secondary
synchronization signal (SSS) as a synchronization signal. The PSS and the SSS are
transmitted at a predetermined timing in a frame structure of a radio frame.
Hereinafter, a specific example of timings of the PSS and the SSS in frequency
division duplex (FDD) and time division duplex (TDD) will be described with
reference to FIGS. 3 and 4.
[0069] FIG. 3 is an explanatory diagram illustrating exemplary timings of a PSS and an SSS
17
WO 2016/017099 PCT/JP2015/003566
in FDD. Referring to FIG. 3, 10 subframes included in the radio frame are illustrated.
In FDD, in subframes (that is, a first subframe and a sixth subframe) having subframe
numbers 0 and 5, the PSS and the SSS are transmitted. More specifically, the SSS is
transmitted in a sixth symbol of a first slot included in each of the subframes, and the
PSS is transmitted in a seventh symbol of the first slot.
[0070] FIG. 4 is an explanatory diagram illustrating exemplary timings of a PSS and an SSS
in TDD. Referring to FIG. 4, 10 subframes included in the radio frame are illustrated.
In TDD, in subframes (that is, a second subframe and a seventh subframe) of subframe
numbers 1 and 6, the PSS is transmitted. More specifically, in a third symbol of a first
slot included in each subframe, the PSS is transmitted. In addition, in TDD, in
subframes (that is, a first subframe and a sixth subframe) of subframe numbers 0 and 5,
the SSS is transmitted. More specifically, in a seventh symbol of a second slot included
in each subframe, the SSS is transmitted.
[0071] When the PSS is detected, the UE can recognize a timing of each subframe. In
addition, when the SSS is detected, the UE can recognize which subframe is a
subframe #0.
[0072] Furthermore, the UE can identify a cell group to which a cell formed by the eNB that
transmits the PSS belongs among three cell groups based on a sequence of the PSS. In
addition, the UE can identify a cell formed by the eNB that transmits the SSS among
168 cell candidates that belong to one cell group based on a sequence of the SSS. That
is, the UE can identify a cell formed by the eNB that transmits the PSS and the SSS
among 504 cell candidates based on the sequence of the PSS and the sequence of the
SSS.
[0073] (Synchronization signal of D2D communication)
For example, when the UE is positioned within the network coverage area, synchronization
for D2D communication is performed based on the synchronization signal
transmitted by the eNB. For example, when the UE is positioned outside of the
network coverage area, synchronization for D2D communication is performed based
on the synchronization signal transmitted by another UE. Also, the synchronization
signal may be a relayed signal.
[0074] The synchronization signal used by a terminal device for D2D communication may
have various attributes. For example, the synchronization signal may have an attribute
of a transmission source. The transmission source may be the eNB or the UE. For
example, the synchronization signal may have an attribute of presence or absence of
relay.
[0075] When the synchronization signal is wirelessly relayed, deterioration of precision of a
center frequency is concerned. Accordingly, it is preferable that the number of relays
(the number of hops) be smaller.
18
WO 2016/017099 PCT/JP2015/003566
[0076] The eNB is more preferable than the UE as the transmission source of the synchronization
signal. This is because precision of an oscillator of the eNB is higher than
precision of an oscillator of the UE.
[0077] (Radio resources available for D2D communication)
(a) Resource pool
As radio resources available for D2D communication, radio resources called a
resource pool are prepared. As the resource pool, periodic radio resources are
considered. For example, the resource pool is represented by a period and an offset (in
a time direction).
[0078] As a method of using the resource pool, two methods may be provided. In the first
method, a management node (for example, the eNB or the UE) allocates radio
resources among the resource pool to the UE and notifies the UE of the radio
resources. The UE can perform D2D communication in the allocated radio resources.
In the second method, the UE selects radio resources from among the resource pool,
and performs D2D communication in the radio resources. The first method is a noncontention-
based method and there is no collision. On the other hand, the second
method is a contention-based method, and collision may occur.
[0079] (b) Multiple resource pools
It is considered natural that multiple resource pools are prepared. In this case, the
period and the offset of the resource pool may be different from periods and offsets of
other resource pools. Also, the period of the resource pool may be the same as periods
of other resource pools while the offset of the resource pool is different from offsets of
the other resource pools.
[0080] Hereinafter, the radio frame and the subframe serving as a unit of time in a cellular
system will be described with reference to FIG. 5. A specific example of the resource
pool will be described with reference to FIG. 6.
[0081] FIG. 5 is an explanatory diagram illustrating a radio frame and subframes in a
cellular system. Referring to FIG. 5, the radio frame and 10 subframes included in one
radio frame are illustrated. Each radio frame is 10 ms, and each subframe is 1 ms. Each
radio frame has a system frame number (SFN) of any of 0 to 1023, and 1024 radio
frames are repeatedly presented.
[0082] FIG. 6 is an explanatory diagram illustrating an exemplary resource pool. Referring
to FIG. 6, two resource pools (that is, a resource pool #1 and a resource pool #2) are illustrated.
The radio resources available for D2D communication are considered to be
periodically arranged in the subframe. For example, the resource pool #1 includes
radio resources of subframes 31 that are repeated at a period 33, and the resource pool
#2 includes radio resources of subframes 35 that are repeated at a period 37. For
example, the period 33 is 200 ms, and the period 37 is 400 ms. Also, in this example,
19
WO 2016/017099 PCT/JP2015/003566
the resource pool #1 and the resource pool #2 have different offsets.
[0083] (c) Signal/information transmitted in resource pool
For example, in the resource pool, a synchronization signal and synchronization information
(information of synchronization) are transmitted by a representative UE. In
addition, the UE performs D2D communication in radio resources other than the radio
resources in which the synchronization signal and the synchronization information are
transmitted among the resource pool. Hereinafter, a specific example thereof will be
described with reference to FIG. 7.
[0084] FIG. 7 is an explanatory diagram illustrating an example of a signal and information
transmitted in a resource pool. Referring to FIG. 7, N resource pools (that is, resource
pools #1 to #N) are illustrated. In each of the N resource pools, the synchronization
signal and the synchronization information are transmitted. In addition, in each of the
N resource pools, D2D communication may be performed in radio resources other than
the radio resources in which the synchronization signal and the information are
transmitted. Also, one UE may transmit the synchronization signal and the synchronization
information in two or more resource pools.
[0085] «2. Schematic Configuration of Communication System»
Next, a schematic configuration of a communication system 1 according to an embodiment
of the present disclosure will be described with reference to FIG. 8. FIG. 8 is
an explanatory diagram illustrating an example of a schematic configuration of the
communication system 1 according to the embodiment of the present disclosure.
Referring to FIG. 8, the communication system 1 includes a base station 100, a
terminal device 200 and a terminal device 300. The communication system 1 is, for
example, a cellular system, and is a system compliant with, for example, LTE, LTEAdvanced,
or communication standards conforming thereto.
[0086] (The base station 100)
The base station 100 performs radio communication with the terminal device. For
example, the base station 100 performs radio communication with the terminal device
200 and the terminal device 300 which are positioned inside a cell 101 of the base
station 100.
[0087] Also, the base station 100 transmits the synchronization signal. Examples of the synchronization
signal include the PSS and the SSS.
[0088] (The terminal device 200)
The terminal device 200 performs radio communication with the base station. For
example, when the terminal device 200 is positioned inside the cell 101 of the base
station 100, the terminal device 200 performs radio communication with the base
station 100.
[0089] The terminal device 200 performs D2D communication. For example, the terminal
20
WO 2016/017099 PCT/JP2015/003566
device 200 transmits the synchronization signal in the resource pool serving as the
radio resources available for D2D communication. In addition, for example, the
terminal device 200 transmits synchronization information (information of synchronization)
in the resource pool.
[0090] Also, in the embodiment of the present disclosure, the terminal device 200 may
operate similarly to, for example, the terminal device 300. For example, the terminal
device 200 operates similarly to the terminal device 300 by switching an operation
mode.
[0091 ] (The terminal device 300)
The terminal device 300 performs radio communication with the base station. For
example, when the terminal device 300 is positioned inside the cell 101 of the base
station 100, the terminal device 300 performs radio communication with the base
station 100.
[0092] The terminal device 300 performs D2D communication. For example, the terminal
device 300 performs synchronization for D2D communication based on the synchronization
signal transmitted by the base station 100 or the synchronization signal
transmitted by the terminal device 200 in the resource pool.
[0093] Also, in FIG. 8, only one base station (that is, the base station 100) included in the
communication system 1 is illustrated. It is needless to say that the communication
system 1 may include multiple base stations. Then, a set of multiple base stations
builds the network coverage area (that is, a coverage area of the cellular network).
[0094] «3. Configuration of Respective Devices»
Exemplary configurations of the base station 100, the terminal device 200 and the
terminal device 300 will be described with reference to FIGS. 9 to 11.
[0095] <3.1. Base Station Configuration»
FIG. 9 is a block diagram illustrating an exemplary configuration of the base station
100 according to the embodiment of the present disclosure. Referring to FIG. 9, the
base station 100 includes an antenna unit 110, a radio communication unit 120, a
network communication unit 130, a storage unit 140 and a processing unit 150.
[0096] (The antenna unit 110)
The antenna unit 110 receives a radio signal and outputs the received radio signal to
the radio communication unit 120. In addition, the antenna unit 110 transmits a
transmission signal output by the radio communication unit 120.
[0097] (The radio communication unit 120)
The radio communication unit 120 transmits and receives a signal. For example, the
radio communication unit 120 transmits a downlink signal to the terminal device and
receives an uplink signal from the terminal device.
[0098] (The network communication unit 130)
21
WO 2016/017099 PCT/JP2015/003566
The network communication unit 130 transmits and receives information. For example,
the network communication unit 130 transmits information to other nodes and receives
information from other nodes. For example, the other nodes include other base stations
and a core network node.
[0099] (The storage unit 140)
The storage unit 140 stores a program and data for operating the base station 100.
[0100] (The processing unit 150)
The processing unit 150 provides various functions of the base station 100. The
processing unit 150 includes an information acquisition unit 151 and a control unit
153. Also, the processing unit 150 may further include a component other than these
components. That is, the processing unit 150 may also perform an operation other than
operations of these components.
[0101] Also, operations of the information acquisition unit 151 and the control unit 153 will
be described in each embodiment.
[0102] <3.2. First Terminal Device Configuration »
FIG. 10 is a block diagram illustrating an exemplary configuration of the terminal
device 200 according to the embodiment of the present disclosure. Referring to FIG.
10, the terminal device 200 includes an antenna unit 210, a radio communication unit
220, a storage unit 230 and a processing unit 240.
[0103] (The antenna unit 210)
The antenna unit 210 receives a radio signal and outputs the received radio signal to
the radio communication unit 220. In addition, the antenna unit 210 transmits a
transmission signal output by the radio communication unit 220.
[0104] (The radio communication unit 220)
The radio communication unit 220 transmits and receives a signal. For example, the
radio communication unit 220 receives a downlink signal from the base station and
transmits an uplink signal to the base station. In addition, for example, the radio communication
unit 220 receives a signal from another terminal device and transmits a
signal to another terminal device.
[0105] (The storage unit 230)
The storage unit 230 stores a program and data for operating the terminal device 200.
[0106] (The processing unit 240)
The processing unit 240 provides various functions of the terminal device 200. The
processing unit 240 includes an information acquisition unit 241 and a control unit
243. Also, the processing unit 240 may further include a component other than these
components. That is, the processing unit 240 may also perform an operation other than
operations of these components.
[0107] Also, operations of the information acquisition unit 241 and the control unit 243 will
22
WO 2016/017099 PCT/JP2015/003566
be described in each embodiment.
[0108] <3.3. Second Terminal Device Configuration »
FIG. 11 is a block diagram illustrating an exemplary configuration of the terminal
device 300 according to the embodiment of the present disclosure. Referring to FIG.
11, the terminal device 300 includes an antenna unit 310, a radio communication unit
320, a storage unit 330 and a processing unit 340.
[0109] (The antenna unit 310)
The antenna unit 310 receives a radio signal and outputs the received radio signal to
the radio communication unit 320. In addition, the antenna unit 310 transmits a
transmission signal output by the radio communication unit 320.
[0110] (The radio communication unit 320)
The radio communication unit 320 transmits and receives a signal. For example, the
radio communication unit 320 receives a downlink signal from the base station and
transmits an uplink signal to the base station. In addition, for example, the radio communication
unit 320 receives a signal from another terminal device and transmits a
signal to another terminal device.
[0111] (The storage unit 330)
The storage unit 330 stores a program and data for operating the terminal device 300.
[0112] (The processing unit 340)
The processing unit 340 provides various functions of the terminal device 300. The
processing unit 340 includes an information acquisition unit 341 and a control unit
343. Also, the processing unit 340 may further include a component other than these
components. That is, the processing unit 340 may also perform an operation other than
operations of these components.
[0113] Also, operations of the information acquisition unit 341 and the control unit 343 will
be described in each embodiment.
[0114] «4. First Embodiment»
Next, the first embodiment of the present disclosure will be described with reference
to FIGS. 12 to 15.
[0115] <4.1.0utline>
(Technical problem)
For example, radio resources (a resource pool) available for D2D communication are
selected by a base station in the case of in-coverage and is selected by a representative
terminal device in the case of out-of-coverage.
[0116] In the case of in-coverage, the base station may notify the terminal device of the
radio resources available for D2D communication. However, when the base station
freely selects the radio resources available for D2D communication without constraints,
the base station may use many radio resources in order to notify the radio
23
WO 2016/017099 PCT/JP2015/003566
resources available for D2D communication. As a result, from the viewpoint of the
radio resources, a load on the base station may become large.
[0117] In the case of out-of-coverage, the representative terminal device may notify another
terminal device of the radio resources available for D2D communication. However,
since the other terminal device does not recognize radio resources that are used by the
representative terminal device to notify the radio resources available for D2D communication,
a trial and error search (for example, a synchronization signal and/or synchronization
information is detected by trial and error) may be performed. As a result, a
load on the other terminal device may become large. In addition, similar to the case of
in-coverage, in the case of out-of-coverage, from the viewpoint of the radio resources,
a load on the representative terminal device may become large.
[0118] Therefore, it is preferable to provide a mechanism in which a load necessary for a
terminal device to recognize the radio resources available for D2D communication can
be reduced.
[0119] (Technical features)
In the first embodiment, the base station 100 and the terminal device 200 notify the
terminal device of one or more resource pools serving as the radio resources available
for D2D communication. The one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource pools that are determined
in advance as candidates for the radio resources available for D2D communication.
Accordingly, it is possible to reduce a load necessary for the terminal device
to recognize the radio resources available for D2D communication.
[0120] <4.2. Operation of Base Station>
First, the operation of the base station 100 will be described with reference to FIG.
12.
[0121] (Notification of resource pool)
The information acquisition unit 151 acquires information indicating one or more
resource pools serving as the radio resources available for D2D communication. Then,
the control unit 153 notifies the terminal device of the one or more resource pools. The
one or more resource pools are resource pools that are selected from among a resource
pool set including multiple resource pools that are determined in advance as candidates
for the radio resources available for D2D communication.
[0122] Also, when it is described that "a resource pool is selected," it may mean that "a
resource pool is allocated." This is not limited to the first embodiment, but is similar to
other embodiments.
[0123] (a) Resource pool set
As described above, the one or more resource pools serving as the radio resources
available for D2D communication are selected from among the resource pool set. An
24
WO 2016/017099 PCT/JP2015/003566
example of the resource pool set will be described below with reference to FIG. 12.
[0124] FIG. 12 is an explanatory diagram illustrating an exemplary resource pool set.
Referring to FIG. 12, a resource pool set including N resource pools that are determined
in advance as candidates for the radio resources available for D2D communication
is illustrated. For example, each of the resource pools includes identification
information for identifying itself and includes radio resources of at least one subframe
of a periodic radio frame represented by a period and an offset. For example, a
resource pool having identification information #1 includes radio resources of one
subframe (a subframe having a subframe number #2) of a periodic radio frame having
the SFNs 0, 20, and 40. For example, a resource pool having identification information
#2 includes radio resources of one subframe (a subframe having a subframe number
#2) of a periodic radio frame having SFNs 10, 50, and 90. For example, a resource
pool having identification information #3 includes radio resources of two subframes
(subframes having subframe numbers #2 and #3) of a periodic radio frame having
SFNs 2, 12, and 22.
[0125] As an example, the resource pool set is determined for each operator (that is, a
carrier) of the cellular system. Also, it is needless to say that the resource pool set may
be determined in a unit other than the operator.
[0126] In addition, the resource pool set may be stored in the terminal device (for example,
the terminal device 200 and the terminal device 300) in advance. Alternatively, the
base station may notify the terminal device (for example, the terminal device 200 and
the terminal device 300) of the resource pool set.
[0127] (b) Selection of resource pool
For example, the base station 100 (for example, the processing unit 150) selects one
or more resource pools available for D2D communication from among the resource
pool set.
[0128] (c) Specific information
For example, each of the multiple resource pools includes identification information
for identifying itself. As an example, the identification information is an identification
number. This is the same as that described with reference to FIG. 12. The control unit
153 notifies the terminal device of the one or more resource pools by transmitting identification
information of each of the one or more resource pools.
[0129] Referring again to FIG. 12, for example, two resource pools having identification information
#1 and #2 are selected from among the resource pool set. In this case, the
control unit 153 transmits these pieces of identification information (#1 and #2) and
thus notifies the terminal device of the two resource pools. Also, the control unit 153
transmits the identification information through the antenna unit 110 and the radio
communication unit 120.
25
WO 2016/017099 PCT/JP2015/003566
[0130] Accordingly, for example, information indicating the period, the offset, and the
subframe of the radio resources is not transmitted, but the identification information is
transmitted. Therefore, it is possible to reduce radio resources necessary for notifying
of the radio resources (resource pool) available for D2D communication.
[0131] (d) Notification method
For example, the control unit 153 notifies the terminal device of the one or more
resource pools by reporting system information indicating the one or more resource
pools. For example, the system information is a predetermined system information
block (SIB).
[0132] Accordingly, for example, not only a terminal device in a connection mode but also a
terminal device in an idle mode can be notified of the one or more resource pools.
[0133] Also, the control unit 153 may notify the terminal device of the one or more resource
pools using separate signaling together with reporting system information or instead of
reporting system information. The separate signaling may be radio resource control
(RRC) signaling. Accordingly, for example, the terminal device in a connection mode
can be notified of more quickly.
[0134] As described above, the base station 100 (the control unit 153) notifies the terminal
device of the one or more resource pools selected from among the resource pool set.
Accordingly, it is possible to reduce a load necessary for the terminal device to
recognize the radio resources available for D2D communication. Specifically, for
example, since radio resources necessary for notifying of the radio resources available
for D2D communication (resource pool) are reduced, a load on the base station 100 is
reduced from the viewpoint of the radio resources. In addition, for example, since the
terminal device may not necessarily perform a trial and error search (for example, the
synchronization signal and/or the synchronization information are detected by trial and
error), a load on the terminal device is reduced.
[0135] (Transmission of synchronization signal)
For example, the base station 100 transmits the synchronization signal. Examples of
the synchronization signal include the PSS and the SSS.
[0136] <4.3. Operation of First Terminal Device>
Next, the operation of the terminal device 200 will be described.
[0137] (Notification of resource pool)
The information acquisition unit 241 acquires information indicating one or more
resource pools serving as the radio resources available for D2D communication. Then,
the control unit 243 notifies the terminal device of the one or more resource pools. The
one or more resource pools are resource pools that are selected from among a resource
pool set including multiple resource pools that are determined in advance as candidates
for the radio resources available for D2D communication.
26
WO 2016/017099 PCT/JP2015/003566
[0138] (a) Resource pool set
There is no difference between the descriptions of the resource pool set of the base
station 100 and the terminal device 200. Therefore, redundant descriptions will be
omitted herein.
[0139] (b) Selection of resource pool
For example, the terminal device 200 (for example, the processing unit 240) selects
one or more resource pools available for D2D communication from among the
resource pool set. For example, when the terminal device 200 is positioned outside of
the network coverage area (that is, a coverage area of the cellular network), in order to
perform out-of-coverage D2D communication (that is, D2D communication outside of
the coverage area of the cellular network), the terminal device 200 selects the one or
more resource pools and notifies the terminal device of the one or more resource pools.
[0140] Also, the base station 100 may select one or more resource pools available for D2D
communication from among the resource pool set, and notify the terminal device 200
of the one or more resource pools. When the terminal device 200 is positioned within
the network coverage area, in order to perform partial-coverage or out-of-coverage
D2D communication, the terminal device (for example, it is positioned outside of the
network coverage area) may be notified of the one or more resource pools of which the
base station 100 notifies the terminal device 200.
[0141] (c) Specific information
For example, each of the multiple resource pools includes identification information
for identifying itself. The control unit 243 notifies the terminal device of the one or
more resource pools by transmitting identification information of each of the one or
more resource pools. There is no difference between the descriptions of the base
station 100 and the terminal device 200 except for different reference numerals.
Therefore, redundant descriptions will be omitted herein.
[0142] (d) Notification method
(d-1) Notification in one or more resource pools
For example, the control unit 243 notifies the terminal device of the one or more
resource pools in each of the one or more resource pools. For example, information indicating
the one or more resource pools is included in synchronization information
(information of synchronization) transmitted in each of the one or more resource pools.
[0143] Referring again to FIG. 12, as an example, three resource pools having identification
information #1, #2, and #N are selected as the resource pool available for D2D communication.
In this case, the control unit 243 notifies the terminal device of the three
resource pools in each of the three resource pools.
[0144] Accordingly, for example, another terminal device may not search for (for example,
detecting the synchronization signal and/or synchronization information) all radio
27
WO 2016/017099 PCT/JP2015/003566
resources, but search for (for example, detecting the synchronization signal and/or synchronization
information) the resource pool included in the resource pool set. In
addition, when one resource pool can be found among the one or more resource pools,
information indicating the one or more resource pools is acquired. Therefore, a load on
the terminal device may be reduced.
[0145] (d-2) Notification in predetermined resource pool
Also, the control unit 243 may notify the terminal device of the one or more resource
pools in a predetermined resource pool included in the resource pool set. The information
indicating the one or more resource pools may also be included in synchronization
information that is transmitted in the predetermined resource pool. Also, the
one or more resource pools may include the predetermined resource pool or may not
include the predetermined resource pool.
[0146] Referring again to FIG. 12, a resource pool having identification information #1 may
be determined in advance as a default resource pool. Then, the control unit 243 may
notify the terminal device of the one or more resource pools in the default resource
pool (that is, the resource pool having identification information #1).
[0147] As an example, the predetermined resource pool is determined for each operator (that
is, a carrier) of the cellular system. Also, it is needless to say that the predetermined
resource pool may be determined in a unit other than the operator.
[0148] In addition, the predetermined resource pool may be stored in the terminal device
(for example, the terminal device 200 and the terminal device 300) in advance. Alternatively,
the base station may notify the terminal device (for example, the terminal
device 200 and the terminal device 300) of the predetermined resource pool.
[0149] As described above, the terminal device may be notified of the one or more resource
pools in the predetermined resource pool. Accordingly, for example, the terminal
device may not perform a trial and error search (for example, detection of the synchronization
signal and/or synchronization information). Therefore, a load on the terminal
device may be reduced.
[0150] Also, it is needless to say that the control unit 243 may notify the terminal device of
the one or more resource pools in a resource pool other than the predetermined
resource pool. For example, the control unit 243 may notify the terminal device of the
one or more resource pools in each of the one or more resource pools.
[0151] (Transmission of synchronization signal)
For example, the terminal device 200 transmits the synchronization signal in each of
the one or more resource pools.
[0152] For example, the control unit 243 controls transmission of the synchronization signal
in each of the one or more resource pools. More specifically, for example, the control
unit 243 maps the synchronization signal to predetermined radio resources of each of
28
WO 2016/017099 PCT/JP2015/003566
the one or more resource pools. Accordingly, for example, the terminal device can be
synchronized for D2D communication.
[0153] <4.4. Operation of Second Terminal Device>
Next, the operation of the terminal device 300 will be described.
[0154] The information acquisition unit 341 acquires information indicating one or more
resource pools serving as the radio resources available for D2D communication. Then,
the control unit 343 controls D2D communication by the terminal device 300 in at least
one resource pool among the one or more resource pools. The one or more resource
pools are resource pools that are selected from among a resource pool set including
multiple resource pools that are determined in advance as candidates for the radio
resources available for D2D communication.
[0155] (One or more resource pools)
For example, the one or more resource pools are resource pools of which the base
station 100 or the terminal device 200 notifies the terminal device 300.
[0156] (Acquisition of information)
(a) When notification is performed by the base station
For example, the base station 100 notifies the terminal device 300 of the one or more
resource pools.
[0157] For example, the base station 100 reporting system information indicating the one or
more resource pools. In this case, the information acquisition unit 341 acquires the information
indicating the one or more resource pools from the system information
received by the terminal device 300.
[0158] Also, the base station 100 may notify the terminal device 300 of the one or more
resource pools using separate signaling. In this case, the information acquisition unit
341 may acquire the information indicating the one or more resource pools from a
message transmitted by the separate signaling. Also, the separate signaling may be
RRC signaling.
[0159] (b) When notification is performed by the terminal device
For example, the terminal device 200 notifies the terminal device 300 of the one or
more resource pools.
[0160] (b-1) Notification in one or more resource pools.
For example, the terminal device 200 notifies the terminal device 300 of the one or
more resource pools in each of the one or more resource pools. In this case, for
example, the information acquisition unit 341 acquires the information indicating the
one or more resource pools from information received by the terminal device 300 in
the resource pool in which the synchronization signal is detected by the terminal
device 300 and that is included in the resource pool set.
[0161] More specifically, for example, referring again to FIG. 12, the terminal device 300
29
WO 2016/017099 PCT/JP2015/003566
sequentially selects resource pools from N resource pools included in the resource pool
set. Detection of the synchronization signal is attempted in the selected resource pool.
Then, the terminal device 300 acquires the information indicating the one or more
resource pools in the resource pool in which the synchronization signal is detected.
[0162] (b-2) Notification in predetermined resource pool
The terminal device 200 may notify the terminal device 300 of the one or more
resource pools in a predetermined resource pool included in the resource pool set. In
this case, the information acquisition unit 341 may acquire the information indicating
the one or more resource pools from information received by the terminal device 300
in the predetermined resource pool.
[0163] (Transmission and reception of signal)
For example, the terminal device 300 performs D2D communication in at least one
resource pool among the one or more resource pools. In this case, the control unit 343
performs a transmission process for transmitting a signal of D2D communication in the
at least one resource pool or a reception process for receiving a signal of D2D communication
in the at least one resource pool.
[0164] <4.5. Process Flow>
Next, an exemplary process according to the first embodiment will be described with
reference to FIGS. 13 to 15.
[0165] (First process)
FIG. 13 is a sequence diagram schematically illustrating an exemplary flow of a first
process according to the first embodiment.
[0166] The base station 100 selects one or more resource pools serving as the radio
resources available for D2D communication from among the resource pool set (S401).
[0167] Then, the base station 100 acquires information indicating the one or more resource
pools, and generates system information indicating the one or more resource pools
(S403). Then, the base station 100 reports the system information (S405).
[0168] The terminal device 300 acquires the information indicating the one or more resource
pools from the system information and performs D2D communication in at least one
resource pool among the one or more resource pools (S407).
[0169] Also, not only the terminal device 300 but also the terminal device 200 may acquire
the information indicating the one or more resource pools from the system information.
In addition, the base station 100 may notify the terminal device 300 (and the terminal
device 200) of the one or more resource pools using separate signaling together with
reporting the system information or instead of reporting the system information. The
separate signaling may be, for example, RRC signaling.
[0170] (Second Process)
(a) First example
30
WO 2016/017099 PCT/JP2015/003566
FIG. 14 is a sequence diagram schematically illustrating a first example of a flow of a
second process according to the first embodiment.
[0171] The terminal device 200 selects one or more resource pools serving as the radio
resources available for D2D communication from among the resource pool set (S411).
[0172] Then, the terminal device 200 notifies the terminal device of the one or more
resource pools in each of the one or more resource pools (S413). For example, the
terminal device 200 transmits resource pool information indicating the one or more
resource pools.
[0173] The terminal device 300 acquires the resource pool information indicating the one or
more resource pools from information received by the terminal device 300 in the
resource pool in which the synchronization signal is detected and that is included in the
resource pool set (S415). Then, the terminal device 300 performs D2D communication
in at least one resource pool among the one or more resource pools (S417).
[0174] (b) Second example
FIG. 15 is a sequence diagram schematically illustrating a second example of a flow
of a second process according to the first embodiment.
[0175] The terminal device 200 selects one or more resource pools serving as the radio
resources available for D2D communication from among the resource pool set (S421).
[0176] Then, the terminal device 200 notifies the terminal device of the one or more
resource pools in at least a predetermined resource pool included in the resource pool
set (S423). For example, the terminal device 200 transmits the resource pool information
indicating the one or more resource pools.
[0177] The terminal device 300 acquires the resource pool information indicating the one or
more resource pools from information received by the terminal device 300 in the predetermined
resource pool (S425). Then, the terminal device 300 performs D2D communication
in at least one resource pool among the one or more resource pools (S427).
[0178] Also, it is needless to say that the terminal device 200 may notify the terminal device
of the one or more resource pools in a resource pool other than the predetermined
resource pool. For example, the terminal device 200 may notify the terminal device of
the one or more resource pools in each of the one or more resource pools.
[0179] «5. Second Embodiments
Next, the second embodiment of the present disclosure will be described with
reference to FIG. 16.
[0180] <5.1.0utline>
(Technical problem)
There is no difference between the descriptions of the technical problems of the first
embodiment and the second embodiment. Therefore, redundant descriptions will be
omitted herein.
31
WO 2016/017099 PCT/JP2015/003566
[0181] (Technical features)
In the second embodiment, the terminal device 200 notifies the terminal device of
one or more resource pools serving as the radio resources available for D2D communication
in the predetermined resource pool. Accordingly, it is possible to reduce a
load necessary for the terminal device to recognize the radio resources available for
D2D communication.
[0182] <5.2. Operation of First Terminal Device>
First, the operation of the terminal device 200 will be described.
[0183] (Notification of resource pool)
The information acquisition unit 241 acquires information indicating one or more
resource pools serving as the radio resources available for D2D communication. Then,
the control unit 243 notifies the terminal device of the one or more resource pools in
the predetermined resource pool. For example, the information indicating the one or
more resource pools is included in synchronization information transmitted in the predetermined
resource pool. Also, the one or more resource pools may include the predetermined
resource pool or may not include the predetermined resource pool.
[0184] Referring again to FIG. 12, as an example, a resource pool having identification information
#1 is determined in advance as a default resource pool. Then, the control
unit 243 notifies the terminal device of the one or more resource pools in the default
resource pool (that is, the resource pool having identification information #1).
[0185] As an example, the predetermined resource pool is determined for each operator (that
is, a carrier) of the cellular system. Also, it is needless to say that the predetermined
resource pool may be determined in a unit other than the operator.
[0186] In addition, the predetermined resource pool may be stored in the terminal device
(for example, the terminal device 200 and the terminal device 300) in advance. Alternatively,
the base station may notify the terminal device (for example, the terminal
device 200 and the terminal device 300) of the predetermined resource pool.
[0187] As described above, the terminal device is to be notified of the one or more resource
pools in the predetermined resource pool. Accordingly, for example, the terminal
device may not perform a trial and error search (for example, detection of the synchronization
signal and/or synchronization information). Therefore, a load on the terminal
device may be reduced.
[0188] (Transmission of synchronization signal)
For example, the terminal device 200 transmits the synchronization signal in each of
the one or more resource pools.
[0189] For example, the control unit 243 controls transmission of the synchronization signal
in each of the one or more resource pools. More specifically, for example, the control
unit 243 maps the synchronization signal to predetermined radio resources of each of
32
WO 2016/017099 PCT/JP2015/003566
the one or more resource pools. Accordingly, for example, the terminal device can be
synchronized for D2D communication.
[0190] <5.4. Operation of Second Terminal Device>
Next, the operation of the terminal device 300 will be described.
[0191] The information acquisition unit 341 acquires information indicating one or more
resource pools serving as the radio resources available for D2D communication from
information received by the terminal device 300 in the predetermined resource pool.
Then, the control unit 343 controls D2D communication by the terminal device 300 in
at least one resource pool among the one or more resource pools.
[0192] (One or more resource pools)
For example, the one or more resource pools are resource pools of which the terminal
device 200 notifies the terminal device 300.
[0193] The terminal device 300 performs D2D communication in at least one resource pool
among the one or more resource pools. In this case, the control unit 343 maps a signal
of D2D communication to radio resources of the at least one resource pool.
[0194] (Transmission and reception of signal)
For example, the terminal device 300 performs D2D communication in at least one
resource pool among the one or more resource pools. In this case, the control unit 343
performs a transmission process for transmitting a signal of D2D communication in the
at least one resource pool or a reception process for receiving a signal of D2D communication
in the at least one resource pool.
[0195] <5.4. Process Flow>
Next, an exemplary process according to the second embodiment will be described
with reference to FIG. 16. FIG. 16 is a sequence diagram schematically illustrating an
exemplary flow of a process according to the second embodiment.
[0196] The terminal device 200 selects one or more resource pools serving as the radio
resources available for D2D communication (S431).
[0197] Then, the terminal device 200 notifies the terminal device of the one or more
resource pools in at least a predetermined resource pool (S433). For example, the
terminal device 200 transmits the resource pool information indicating the one or more
resource pools.
[0198] The terminal device 300 acquires the resource pool information indicating the one or
more resource pools from information received by the terminal device 300 in the predetermined
resource pool (S435). Then, the terminal device 300 performs D2D communication
in at least one resource pool among the one or more resource pools (S437).
[0199] Also, it is needless to say that the terminal device 200 may notify the terminal device
of the one or more resource pools in a resource pool other than the predetermined
resource pool. For example, the terminal device 200 may notify the terminal device of
33
WO 2016/017099 PCT/JP2015/003566
the one or more resource pools in each of the one or more resource pools.
[0200] «6. Third Embodiment»
Next, the third embodiment of the present disclosure will be described with reference
to FIGS. 17 to 19.
[0201] <6.1.0utline>
(Technical problem)
One or more resource pools serving as the radio resources available for D2D communication
may be changed as necessary. As an example, a new resource pool may be
added to the one or more resource pools. As another example, the resource pool
included in the one or more resource pools may be deleted. As still another example,
when D2D communication is performed in a specific application in the resource pool,
the specific application may be changed. In order to avoid collision, it is preferable that
the terminal device be appropriately notified of this change in the resource pool.
[0202] For example, in the case of in-coverage, the base station may notify the terminal
device of the change in the resource pool in system information. However, since an
update frequency of the system information is very low, it is difficult to notify the
change quickly.
[0203] On the other hand, in the case of out-of-coverage, the representative terminal device
may notify of the change in the resource pool. However, when the change is notified of
in all resource pools, a great amount of the radio resources may be used. On the other
hand, when the change is notified of in an arbitrarily selected resource pool, only the
terminal device configured to perform D2D communication in the arbitrarily selected
resource pool can recognize the change.
[0204] Therefore, it is preferable to provide a mechanism in which the terminal device can
be appropriately notified of the change in the resource pool.
[0205] (Technical features)
In the third embodiment, the terminal device 200 notifies the terminal device of the
change in the resource pool in a primary resource pool among one or more resource
pools serving as the radio resources available for D2D communication. Accordingly,
for example, the terminal device can be appropriately notified of the change in the
resource pool.
[0206] <6.2. Operation of First Terminal Device>
First, the operation of the terminal device 200 will be described.
[0207] (Notification of change in resource pool)
The information acquisition unit 241 acquires information indicating the change in
the resource pool serving as the radio resources available for D2D communication.
Then, the control unit 243 notifies the terminal device of the change in the primary
resource pool among one or more resource pools serving as the radio resources
34
WO 2016/017099 PCT/JP2015/003566
available for D2D communication.
[0208] (a) Primary resource pool
The primary resource pool is one special resource pool among the one or more
resource pools. As an example, referring again to FIG. 7, a resource pool #1 among N
resource pools is the primary resource pool.
[0209] (a-1) Out-of-coverage
For example, when the terminal device 200 is positioned outside of the network
coverage area (that is, a coverage area of the cellular network), the information acquisition
unit 241 acquires the information indicating the change. The control unit 243
notifies the terminal device of the change. In this case, for example, the one or more
resource pools are resource pools selected by the terminal device 200, and the primary
resource pool is a resource pool unique to the terminal device 200. For example, the
terminal device 200 (for example, the processing unit 240) selects the primary resource
pool from the one or more resource pools.
[0210] (a-2) In-coverage
Even when the terminal device 200 is positioned within the network coverage area,
the information acquisition unit 241 acquires the information indicating the change,
and the control unit 243 may notify the terminal device of the change. In this case, the
one or more resource pools may be a resource pool selected by the base station 100,
and the primary resource pool may be a resource pool unique to the base station 100.
For example, the base station 100 may select the primary resource pool from the one or
more resource pools, and may notify the terminal device 200 of the one or more
resource pools and the primary resource pool.
[0211] (b) Change in resource pool
The change includes deleting the resource pool, adding the resource pool, changing
the primary resource pool, or changing an application of D2D communication
performed in the resource pool.
[0212] The application includes an urgent application, a non-urgent application, an application
for public safety (for example, fire notification and/or collision avoidance),
an application other than one for public safety, an out-of-coverage application, or an
in-coverage application. As an example, the change is a change of the application of
D2D communication that is performed in the resource pool between the in-coverage
application and the out-of-coverage application. As another example, the change is a
change of the application of D2D communication that is performed in the resource
pool between fire notification and collision avoidance.
[0213] For example, as described above, the primary resource pool is a resource pool unique
to the terminal device 200. In this case, the terminal device 200 determines the change.
Also, as described above, the primary resource pool may be a resource pool unique to
35
WO 2016/017099 PCT/JP2015/003566
the base station 100. In this case, the base station 100 may determine the change.
[0214] (Notification of primary resource pool)
For example, the control unit 243 notifies the terminal device of the primary resource
pool.
[0215] For example, the control unit 243 notifies the terminal device of the primary resource
pool in at least one resource pool among the one or more resource pools. As an
example, the control unit 243 notifies the terminal device of the primary resource pool
in each of the one or more resource pools. Alternatively, the control unit 243 may
notify the terminal device of the primary resource pool in a predetermined resource
pool (for example, a default resource pool having identification information #1 illustrated
in FIG. 11).
[0216] For example, information indicating the primary resource pool is included in the synchronization
information transmitted in the resource pool.
[0217] For example, when the terminal device 200 is positioned outside of the network
coverage area, the control unit 243 notifies the terminal device of the primary resource
pool. Also, even when the terminal device 200 is positioned within the network
coverage area (especially, inside the cell 101 of the base station 100), the control unit
243 may notify the terminal device of the primary resource pool. In this case, the base
station 100 may notify the terminal device 200 of the primary resource pool.
[0218] (Notification of resource pool)
For example, the control unit 243 notifies the terminal device of the one or more
resource pools.
[0219] For example, similar to the first embodiment or the second embodiment of the
present disclosure, the control unit 243 may notify the terminal device of the one or
more resource pools.
[0220] For example, when the terminal device 200 is positioned outside of the network
coverage area, the control unit 243 notifies the terminal device of the one or more
resource pool. Also, even when the terminal device 200 is positioned within the
network coverage area (especially, inside the cell 101 of the base station 100), the
control unit 243 may notify the terminal device of the one or more resource pool. In
this case, the base station 100 may notify the terminal device 200 of the one or more
resource pool.
[0221] As described above, the control unit 243 notifies the terminal device of the change in
the resource pool in the primary resource pool among one or more resource pools
serving as the radio resources available for D2D communication. Accordingly, for
example, the terminal device can be appropriately notified of the change in the
resource pool. For example, when the terminal device 300 awaits notification of the
change in the resource pool in the primary resource pool, it is possible to recognize the
36
WO 2016/017099 PCT/JP2015/003566
change reliably. In addition, radio resources necessary for notifying of the change may
be reduced.
[0222] <6.3. Operation of Second Terminal Device>
Next, the operation of the terminal device 300 will be described.
[0223] The information acquisition unit 341 acquires the information indicating the change
in the resource pool serving as the radio resources available for D2D communication.
Then, the control unit 343 controls D2D communication by the terminal device 300 in
at least one resource pool in accordance with the change.
[0224] (Acquisition of information indicating change in resource pool)
(a) Acquisition from information transmitted by the terminal device
For example, the information acquisition unit 341 acquires the information indicating
the change from information received by the terminal device 300 in the primary
resource pool among one or more resource pools serving as the radio resources
available for D2D communication.
[0225] (b) Acquisition from information transmitted by the base station
Also, when the terminal device 300 is positioned within the network coverage area
(especially, within the cell 101 of the base station 100), the information acquisition
unit 341 acquires the information indicating the change from the system information
reported by the base station 100 or a message transmitted by the base station 100 to the
terminal device 300 using separate signaling. The separate signaling may be, for
example, RRC signaling.
[0226] (One or more resource pools)
For example, the one or more resource pools are resource pools of which the base
station 100 or the terminal device 200 notifies the terminal device 300.
[0227] (Primary resource pool)
For example, the primary resource pool is a resource pool of which the base station
100 or the terminal device 200 notifies the terminal device 300.
[0228] (D2D communication according to change)
(a) Exemplary D2D communication according to change
When the change indicates adding of the resource pool, for example, the control unit
343 controls D2D communication by the terminal device 300 such that the terminal
device 300 performs D2D communication in the added resource pool.
[0229] When the change indicates deleting of the resource pool, for example, the control
unit 343 controls D2D communication by the terminal device 300 such that the
terminal device 300 performs no D2D communication in the deleted resource pool.
[0230] When the change indicates changing of the primary resource pool, for example, the
control unit 343 controls D2D communication by the terminal device 300 such that the
terminal device 300 (the information acquisition unit 341) acquires information in37
WO 2016/017099 PCT/JP2015/003566
dicating the change in the resource pool from information received in the changed
primary resource pool.
[0231] When the change indicates changing of the application of D2D communication
performed in the resource pool, for example, the control unit 343 controls D2D communication
by the terminal device 300 such that the terminal device 300 performs D2D
communication in the changed application without performing D2D communication in
the application before the change in the resource pool to be changed.
[0232] (b) Exemplary process
As a specific process, for example, the control unit 343 changes an operation
parameter of D2D communication in accordance with the change in the resource pool.
[0233] <6.4. Operation of Base Station>
Next, the operation of the base station 100 will be described.
[0234] (Notification of change in resource pool)
The information acquisition unit 151 acquires information indicating the change in
the resource pool serving as the radio resources available for D2D communication. The
control unit 153 notifies the terminal device of the change by at least one of reporting
of the system information indicating the change and separate signaling.
[0235] (a) Primary resource pool
The primary resource pool is one special resource pool among the one or more
resource pools.
[0236] For example, the one or more resource pools are resource pools selected by the base
station 100 (for example, the processing unit 150), and the primary resource pool is a
resource pool unique to the base station 100. For example, the base station 100 (for
example, the processing unit 150) selects the primary resource pool from the one or
more resource pools.
[0237] (b) Change in resource pool
There is no difference between the descriptions of the change in the resource pool of
the terminal device 200 and the base station 100. Therefore, redundant descriptions
will be omitted herein.
[0238] (Notification of resource pool)
For example, the control unit 153 notifies the terminal device of the one or more
resource pools. Specifically, for example, the control unit 153 notifies the terminal
device of the one or more resource pools by at least one of reporting of the system information
indicating the one or more resource pools and separate signaling. The
separate signaling may be, for example, RRC signaling.
[0239] <6.5. Process Flow>
Next, an exemplary process according to the third embodiment will be described
with reference to FIGS. 17 to 19.
38
WO 2016/017099 PCT/JP2015/003566
[0240] (First Process)
FIG. 17 is a sequence diagram schematically illustrating an exemplary flow of a first
process according to the third embodiment.
[0241] The terminal device 200 notifies the terminal device of one or more resource pools
serving as the radio resources available for D2D communication and the primary
resource pool among the one or more resource pools (S441). For example, the terminal
device 200 transmits the resource pool information indicating the one or more resource
pools and primary resource pool information indicating the primary resource pool.
[0242] The terminal device 300 performs D2D communication in at least one resource pool
among the one or more resource pools (S442).
[0243] The terminal device 200 determines the change in the resource pool (S443), and
notifies the terminal device of the change in the primary resource pool (S444). For
example, the terminal device 200 transmits the resource pool change information indicating
the change in the primary resource pool.
[0244] The terminal device 300 acquires the information indicating the change from information
received by the terminal device 300 in the primary resource pool (S445).
Then, the terminal device 300 performs D2D communication in at least one resource
pool in accordance with the change (S446).
[0245] (Second Process)
FIG. 18 is a sequence diagram schematically illustrating an exemplary flow of a
second process according to the third embodiment.
[0246] The base station 100 reports the system information indicating one or more resource
pools serving as the radio resources available for D2D communication and the primary
resource pool among the one or more resource pools (S451).
[0247] The terminal device 300 performs D2D communication in at least one resource pool
among the one or more resource pools (S453).
[0248] The base station 100 determines the change in the resource pool (S455), and reports
the system information indicating the change (S457).
[0249] The terminal device 300 performs D2D communication in at least one resource pool
in accordance with the change (S459).
[0250] (Third process)
FIG. 19 is a sequence diagram schematically illustrating an exemplary flow of a third
process according to the third embodiment.
[0251] The base station 100 reports the system information indicating one or more resource
pools serving as the radio resources available for D2D communication and the primary
resource pool among the one or more resource pools (S461).
[0252] The terminal device 300 performs D2D communication in at least one resource pool
among the one or more resource pools (S462).
39
WO 2016/017099 PCT/JP2015/003566
[0253] The base station 100 determines the change in the resource pool (S463), and notifies
the terminal device 200 of the change using separate signaling (S464). For example,
the base station 100 transmits resource pool change information indicating the change
to the terminal device 200.
[0254] The terminal device 200 notifies the terminal device of the change in the primary
resource pool (S465). For example, the terminal device 200 transmits the resource pool
change information indicating the change in the primary resource pool.
[0255] The terminal device 300 acquires the information indicating the change from information
received by the terminal device 300 in the primary resource pool (S466).
Then, the terminal device 300 performs D2D communication in at least one resource
pool in accordance with the change (S467).
[0256] «7. Fourth Embodiment»
Next, the fourth embodiment of the present disclosure will be described with
reference to FIG. 20.
[0257] <7.1.0utline>
(Technical problem)
For example, it is preferable that a resource pool serving as the radio resources
available for in-coverage D2D communication (that is, D2D communication within the
network coverage area) and a resource pool serving as the radio resources available for
out-of-coverage D2D communication (that is, D2D communication outside of the
network coverage area) be separately prepared. As the first reason, the synchronization
signal for in-coverage D2D communication and the synchronization signal for outof-
coverage D2D communication have different transmission sources. As the second
reason, interference with radio communication from in-coverage D2D communication
to the base station and interference with radio communication from out-of-coverage
D2D communication to the base station are completely different.
[0258] However, it may be difficult to clearly determine whether the terminal device is positioned
within the network coverage area or positioned outside of the network
coverage area. Therefore, for example, when the terminal device transmits a signal in
an out-of-coverage resource pool or an in-coverage resource pool, a failure may occur.
As a result, other terminal devices may not receive the signal.
[0259] Therefore, it is preferable to provide a mechanism in which other terminal devices
can receive a signal of D2D communication more reliably.
[0260] (Technical features)
In the fourth embodiment, when received power of the terminal device of the signal
transmitted by the base station is less than first power and is greater than second power
which is less than the first power, the terminal device (the terminal device 200 or the
terminal device 300) transmits a signal of D2D communication in both of the in40
WO 2016/017099 PCT/JP2015/003566
coverage resource pool and the out-of-coverage resource pool. Accordingly, for
example, other terminal devices can receive a signal of D2D communication more
reliably.
[0261] <7.2. Operation of Base Station>
First, the operation of the base station 100 will be described.
[0262] The information acquisition unit 151 acquires information indicating the in-coverage
resource pool serving as the radio resources available for D2D communication within
the network coverage area and the out-of-coverage resource pool serving as the radio
resources available for D2D communication outside of the network coverage area.
Then, the control unit 153 notifies the terminal device of the in-coverage resource pool
and the out-of-coverage resource pool.
[0263] (In-coverage resource pool and out-of-coverage resource pool)
For example, the base station 100 (for example, the processing unit 150) selects the
in-coverage resource pool and the out-of-coverage resource pool.
[0264] (Notification method)
For example, the control unit 153 notifies the terminal device of the in-coverage
resource pool and the out-of-coverage resource pool by reporting the system information
indicating the in-coverage resource pool and the out-of-coverage resource
pool.
[0265] Also, the control unit 153 may notify the terminal device of the in-coverage resource
pool and the out-of-coverage resource pool using separate signaling. The separate
signaling may be RRC signaling.
[0266] <7.3. Operation of First Terminal Device>
Next, the operation of the terminal device 200 will be described.
[0267] The information acquisition unit 241 acquires information indicating the in-coverage
resource pool and the out-of-coverage resource pool.
[0268] (First case)
For example, received power of the terminal device 200 of the signal transmitted by
the base station is less than first power and is greater than second power which is less
than the first power. In this case, the control unit 243 controls D2D communication by
the terminal device 200 such that the terminal device 200 transmits a signal of D2D
communication in both of the in-coverage resource pool and the out-of-coverage
resource pool.
[0269] Accordingly, for example, other terminal devices can receive a signal of D2D communication
more reliably. That is, even when it is difficult to determine whether the
terminal device 200 is positioned within the network coverage area or is positioned
outside of the network coverage area, other terminal devices can receive a signal
transmitted by the terminal device 200. That is, other terminal devices configured to
41
WO 2016/017099 PCT/JP2015/003566
perform D2D communication in the out-of-coverage resource pool and other terminal
devices configured to perform D2D communication in the in-coverage resource pool
can receive a signal.
[0270] Also, since the first power and the second power are provided, an effect (that is, a
ping-pong effect) in which transmission of a signal in the out-of-coverage resource
pool and transmission of a signal in the in-coverage resource pool are switched in a
short time due to a variation of the received power may be avoided.
[0271] Furthermore, for example, the control unit 243 controls D2D communication by the
terminal device 200 such that the terminal device 200 transmits a signal of the same information
in both of the in-coverage resource pool and the out-of-coverage resource
pool. Accordingly, for example, other terminal devices can acquire the same information
regardless of out-of-coverage and in-coverage.
[0272] (Second case)
For example, when the received power is greater than the first power, the control unit
243 controls D2D communication by the terminal device 200 such that the terminal
device 200 transmits a signal of D2D communication in the in-coverage resource pool.
[0273] Also, when the received power is equal to the first power, the control unit 243 may
control D2D communication by the terminal device 200 such that the terminal device
200 transmits a signal of D2D communication in the in-coverage resource pool. Alternatively,
when the received power is equal to the first power, the control unit 243 may
control D2D communication by the terminal device 200 such that the terminal device
200 transmits a signal of D2D communication in both of the in-coverage resource pool
and the out-of-coverage resource pool.
[0274] (Third case)
For example, when the received power is less than the second power, the control unit
243 controls D2D communication by the terminal device 200 such that the terminal
device 200 transmits a signal of D2D communication in the out-of-coverage resource
pool.
[0275] Also, when the received power is equal to the second power, the control unit 243
may control D2D communication by the terminal device 200 such that the terminal
device 200 transmits a signal of D2D communication in the out-of-coverage resource
pool. Alternatively, when the received power is equal to the second power, the control
unit 243 may control D2D communication by the terminal device 200 such that the
terminal device 200 transmits a signal of D2D communication in both of the incoverage
resource pool and the out-of-coverage resource pool.
[0276] (Received power)
For example, the signal transmitted by the base station is a reference signal. As an
example, the signal transmitted by the base station is a cell-specific reference signal
42
WO 2016/017099 PCT/JP2015/003566
(CRS). In addition, as an example, the received power is reference signal received
power (RSRP).
[0277] For example, when multiple base stations of the cellular network are provided in
vicinity of the terminal device 200, multiple levels of received power (for example,
multiple levels of RSRP) are measured. In this case, the received power is, for
example, the highest received power among multiple levels of received power.
[0278] Also, the signal may be a signal transmitted by the base station 100 or a signal
transmitted by another base station.
[0279] (Specific process)
For example, the control unit 243 performs a transmission process for transmitting a
signal of D2D communication in the in-coverage resource pool. In addition, the control
unit 343 performs a transmission process for transmitting a signal of D2D communication
in the out-of-coverage resource pool.
[0280] <7.4. Operation of Second Terminal Device>
Description of the operation of the terminal device 300 is the same as description of
the operation of the terminal device 200 except for different reference numerals.
Therefore, redundant descriptions will be omitted herein.
[0281] <7.5. Process Flow>
Next, an exemplary process according to the fourth embodiment will be described
with reference to FIG. 20. FIG. 20 is a flowchart schematically illustrating an
exemplary flow of a process according to the fourth embodiment. The process is a
process performed by the terminal device 200.
[0282] The terminal device 200 (for example, the processing unit 240) measures received
power of the signal transmitted by the base station (S471).
[0283] When the received power is greater than X dB (YES in S473), the terminal device
200 transmits a signal of D2D communication in the in-coverage resource pool (S474).
Then, the process returns to step S471.
[0284] When the received power is equal to or less than X dB (NO in S473) and the
received power is greater than Y dB (YES in S475), the terminal device 200 transmits
a signal of D2D communication in both of the in-coverage resource pool and the outof-
coverage resource pool (S476). Then, the process returns to step S471.
[0285] When the received power is equal to or less than Y dB (NO in S475), the terminal
device 200 transmits a signal of D2D communication in the out-of-coverage resource
pool (S478). Then, the process returns to step S471.
[0286] Also, the process may be similarly executed in the terminal device 300.
[0287] «8. Fifth Embodiment»
Next, the fifth embodiment of the present disclosure will be described with reference
to FIGS. 21 to 24.
43
WO 2016/017099 PCT/JP2015/003566
[0288] <8.1.0utline>
(Technical problem)
For example, multiple resource pools serving as the radio resources available for
D2D communication may be prepared for D2D communication.
[0289] When multiple terminal devices that are not synchronized use the same resource
pool, not only may a signal receivable by the terminal device be transmitted but a
signal unreceivable by the terminal device may also be transmitted in the same
resource pool. Therefore, the synchronized terminal device preferably performs D2D
communication in one resource.
[0290] For example, the terminal device is synchronized based on the synchronization signal
transmitted by the base station for in-coverage D2D communication, and is synchronized
based on the synchronization signal transmitted by the representative
terminal device for out-of-coverage D2D communication.
[0291] For example, multiple resource pools are prepared for the terminal device synchronized
by the synchronization signal transmitted by the base station. In addition, for
example, multiple resource pools may be prepared for the terminal device synchronized
by the synchronization signal transmitted by the representative terminal
device. In this case, synchronized multiple terminal devices may perform D2D communication
in multiple resource pools.
[0292] However, when D2D communication is performed in, for example, multiple resource
pools, the terminal device is synchronized based on the synchronization signal
transmitted in each of the multiple resource pools. Therefore, for example, when the
number of resource pools increases, a load on the synchronization process increases.
[0293] Therefore, it is preferable to provide a mechanism in which a load on the synchronization
process in the terminal device configured to perform D2D communication can
be reduced.
[0294] (Technical features)
In the fifth embodiment, the base station 100 and the terminal device 200 notify the
terminal device of the resource pool group that is used by the synchronized terminal
device and is the resource pool group including one or more resource pools serving as
the radio resources available for D2D communication. Accordingly, for example, it is
possible to reduce a load on the synchronization process in the terminal device
configured to perform D2D communication.
[0295] <8.2. Operation of Base Station>
First, the operation of the base station 100 will be described with reference to FIG.
21.
[0296] The information acquisition unit 151 acquires information indicating the resource
pool group that is used by the synchronized terminal device and that is the resource
44
WO 2016/017099 PCT/JP2015/003566
pool group including one or more resource pools serving as the radio resources
available for D2D communication. Then, the control unit 153 notifies the terminal
device of the resource pool group.
[0297] (Synchronized terminal device)
(a) The same transmission source
For example, the synchronized terminal device includes a terminal device that is synchronized
based on the synchronization signal transmitted by one transmission source.
[0298] As a first example, the synchronized terminal device includes a terminal device that
is synchronized based on the synchronization signal transmitted by the base station
100.
[0299] As a second example, the synchronized terminal device includes a terminal device
that is synchronized based on the synchronization signal transmitted by the terminal
device 200.
[0300] (b) Other transmission sources
The synchronized terminal device may further include a terminal device that is synchronized
based on the synchronization signal transmitted by other transmission
sources that are synchronized with the one transmission source. More specifically, the
other transmission sources may also include a transmission source configured to relay
the synchronization signal transmitted by the one transmission source.
[0301] As a first example, the synchronized terminal device may also include a terminal
device that is synchronized based on the synchronization signal transmitted by the base
station 100 and a terminal device that is synchronized based on the synchronization
signal transmitted by a device (for example, the terminal device 200 or a relay station)
that relays the synchronization signal.
[0302] As a second example, the synchronized terminal device may also include a terminal
device that is synchronized based on the synchronization signal transmitted by the
terminal device 200 and a terminal device that is synchronized based on the synchronization
signal transmitted by a device (for example, the terminal device 200) that
relays the synchronization signal.
[0303] Accordingly, for example, a greater number of terminal devices may use the same
resource pool.
[0304] (Resource pool group)
For example, the resource pool group includes two or more resource pools serving as
the radio resources available for D2D communication. Also, the resource pool group
may include only one resource pool.
[0305] For example, the control unit 153 notifies the terminal device of multiple resource
pools group. An exemplary resource pool group will be described below with reference
to FIG. 21.
45
WO 2016/017099 PCT/JP2015/003566
[0306] FIG. 21 is an explanatory diagram illustrating a first example of the resource pool
group. For example, resource pools #1, #4, and #N are included in a resource pool
group #1. For example, the resource pool group #1 is used by a terminal device that is
synchronized based on the synchronization signal transmitted by a certain terminal
device 200. In addition, for example, resource pools #2 and #3 are included in a
resource pool group #2. For example, the resource pool group #2 is used by a terminal
device that is synchronized based on the synchronization signal transmitted by the base
station 100. In addition, a resource pool #5 is included in a resource pool group #3. For
example, the resource pool group #3 is used by a terminal device that is synchronized
based on the synchronization signal transmitted by another terminal device 200.
[0307] (Transmission information)
As an example, the control unit 153 notifies the terminal device of the resource pool
group by transmission of information (for example, information as illustrated in FIG.
21) indicating the resource pool group to which resource pools belong.
[0308] (Notification method)
For example, the control unit 153 notifies the terminal device of the resource pool
group by reporting the system information indicating the resource pool group. Accordingly,
for example, not only the terminal device in a connection mode but also the
terminal device in an idle mode can recognize the resource pool group.
[0309] Also, the control unit 153 may notify the terminal device of the resource pool group
using separate signaling. The separate signaling may be RRC signaling.
[0310] As described above, the base station 100 (the control unit 153) notifies the terminal
device of the resource pool group. Accordingly, for example, the terminal device can
reduce a load on the synchronization process. Specifically, for example, the terminal
device can omit synchronization based on the synchronization signal transmitted in the
resource pool group included in the resource pool group. As an example, the terminal
device already uses the resource pool #1 illustrated in FIG. 21. In this case, when the
terminal device uses synchronization in the resource pool #1 as synchronization in the
resource pools #4 and #N, it is possible to omit synchronization based on the synchronization
signal transmitted in resource pools #4 and #N. As another example, the
terminal device already uses the resource pool #2 illustrated in FIG. 21. In this case,
when the terminal device uses synchronization in the resource pool #2 as synchronization
in the resource pool #3, it is possible to omit synchronization based on the
synchronization signal transmitted in the resource pool #3.
[0311] <8.3. Operation of First Terminal Device>
Next, the operation of the terminal device 200 will be described with reference to
FIG. 22.
[0312] The information acquisition unit 241 acquires information indicating the resource
Title of Invention: DEVICE
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Japanese Priority Patent Application JP
2014-154714 filed July 30, 2014, the entire contents of which are incorporated herein
by reference.
Technical Field
[0002] The present disclosure relates to a device.
Background Art
[0003] Device-to-device communication (D2D communication) is communication in which
two or more terminal devices transmit and receive signals directly, unlike typical
cellular communication in which a base station and a terminal device transmit and
receive signals. For this reason, it is anticipated that D2D communication will be used
to create new usage scenarios for terminal devices that differ from the typical cellular
communication above. For example, various applications are conceivable, such as information
sharing by data communication between nearby terminal devices or among a
group of nearby terminal devices, distribution of information from an installed terminal
device, and autonomous communication between machines, called machineto-
machine (M2M) communication.
[0004] Additionally, it is conceivable that D2D communication will be put to effective use
in data offloading in response to the significant increase in data traffic due to the recent
increase in smartphones. For example, in recent years, there has been a sharp rise in the
necessity to transmit and receive video image streaming data. However, since video
images typically have large data sizes, there is a problem of consuming many resources
on a radio access network (RAN). Consequently, if terminal devices are in a state
suitable for D2D communication with each other, such as when the terminal devices
are a short distance away from each other, video image data may be offloaded to D2D
communication, thereby moderating the resource consumption and processing load on
a RAN. In this way, D2D communication provides value to both telecommunications
carriers and users. For this reason, D2D communication is currently recognized as one
crucial technology area for Long Term Evolution (LTE), and is receiving attention
from the 3rd Generation Partnership Project (3GPP) standards committee.
[0005] For example, Non Patent Literature 1 discloses technology such as synchronization
and discovery of D2D communication.
Citation List
Non Patent Literature
2
WO 2016/017099 PCT/JP2015/003566
[0006] [NPL 1] 3GPP TR 36.843 V12.0.0 (March 2014)
Summary
Technical Problem
[0007] In Non Patent Literature 1, a method of a terminal device recognizing radio resources
available for D2D communication is not disclosed.
[0008] For example, radio resources (a resource pool) available for D2D communication are
selected by a base station in the case of in-coverage and is selected by a representative
terminal device in the case of out-of-coverage.
[0009] In the case of in-coverage, the base station may notify the terminal device of the
radio resources available for D2D communication. However, when the base station
freely selects the radio resources available for D2D communication without constraints,
the base station may use many radio resources in order to notify the radio
resources available for D2D communication. As a result, from the viewpoint of the
radio resources, a load on the base station may become large.
[0010] In the case of out-of-coverage, the representative terminal device may notify another
terminal device of the radio resources available for D2D communication. However,
since the other terminal device does not recognize radio resources that are used by the
representative terminal device to notify the radio resources available for D2D communication,
a trial and error search (for example, a synchronization signal and/or synchronization
information (information of synchronization) is detected by trial and error)
may be performed. As a result, a load on the other terminal device may become large.
In addition, similar to the case of in-coverage, in the case of out-of-coverage, from the
viewpoint of the radio resources, a load on the representative terminal device may
become large.
[0011] Therefore, it is preferable to provide a mechanism in which a load necessary for a
terminal device to recognize the radio resources available for D2D communication can
be reduced.
Solution to Problem
[0012] According to an exemplary embodiment of the present disclosure, there is provided a
device including: an acquisition unit configured to acquire information indicating one
or more resource pools serving as radio resources available for device-to-device communication;
and a control unit configured to notify a terminal device of the one or
more resource pools. The one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource pools, which are
determined in advance as candidates for radio resources available for device-to-device
communication.
[0013] According to another exemplary embodiment of the present disclosure, there is
3
WO 2016/017099 PCT/JP2015/003566
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to control device-to-device
communication by a terminal device in at least one resource pool among the one or
more resource pools. The one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource pools, which are
determined in advance as candidates for radio resources available for device-to-device
communication.
[0014] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the one or more resource pools in a predetermined resource pool.
[0015] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
one or more resource pools serving as radio resources available for deviceto-
device communication from information received by a terminal device in a predetermined
resource pool; and a control unit configured to control device-to-device communication
by the terminal device in at least one resource pool among the one or more
resource pools.
[0016] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the change in a primary resource pool among one or more resource pools serving as
radio resources available for device-to-device communication.
[0017] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication from information received by a terminal device in a primary
resource pool among one or more resource pools serving as radio resources available
for device-to-device communication; and a control unit configured to control deviceto-
device communication by the terminal device in at least one resource pool in accordance
with the change.
[0018] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a change in a resource pool serving as a radio resource available for deviceto-
device communication; and a control unit configured to notify a terminal device of
4
WO 2016/017099 PCT/JP2015/003566
the change by at least one of reporting of system information indicating the change and
separate signaling.
[0019] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an in-coverage resource pool serving as a radio resource available for deviceto-
device communication within a network coverage area and an out-of-coverage
resource pool serving as a radio resource available for device-to-device communication
outside of the network coverage area; and a control unit configured to control deviceto-
device communication by a terminal device in a manner that the terminal device
transmits a signal of device-to-device communication in both of the in-coverage
resource pool and the out-of-coverage resource pool when received power in the
terminal device of a signal transmitted by a base station is less than first power and is
greater than second power which is less than the first power.
[0020] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an in-coverage resource pool serving as a radio resource available for deviceto-
device communication within a network coverage area and an out-of-coverage
resource pool serving as a radio resource available for device-to-device communication
outside of the network coverage area; and a control unit configured to notify a terminal
device of the in-coverage resource pool and the out-of-coverage resource pool.
[0021] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a resource pool group that is used by a synchronized terminal device and
includes one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to notify a terminal device of
the resource pool group.
[0022] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a resource pool group that is used by a synchronized terminal device and
includes one or more resource pools serving as radio resources available for deviceto-
device communication; and a control unit configured to control device-to-device
communication by a terminal device in a manner that the terminal device omits synchronization
based on a synchronization signal transmitted in at least one resource pool
included in the resource pool group.
[0023] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an application of device-to-device communication that is performed in each of
one or more resource pools serving as radio resources available for device-to-device
5
WO 2016/017099 PCT/JP2015/003566
communication; and a control unit configured to notify a terminal device of the application.
[0024] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an application of device-to-device communication that is performed in each of
one or more resource pools serving as radio resources available for device-to-device
communication; and a control unit configured to control device-to-device communication
by a terminal device in a manner that the terminal device performs deviceto-
device communication in a desired application in a resource pool in which deviceto-
device communication is performed in the desired application among the one or
more resource pools.
[0025] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a desired application of device-to-device communication of a terminal device;
and a control unit configured to notify the terminal device of one or more resource
pools in which device-to-device communication is performed in the desired application
and which are one or more resource pools serving as radio resources available for
device-to-device communication.
[0026] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a desired application of device-to-device communication of a terminal device;
and
a control unit configured to notify a base station or another terminal device of the
desired application. The control unit controls device-to-device communication in the
desired application by the terminal device in at least one resource pool among one or
more resource pools of which the base station or the other terminal device notifies the
terminal device. The one or more resource pools are radio resources available for
device-to-device communication and are resource pools in which device-to-device
communication is performed in the desired application.
[0027] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
the number of terminal devices configured to perform device-to-device communication;
and a control unit configured to select a resource pool serving as a radio
resource available for device-to-device communication based on the number of
terminal devices configured to perform device-to-device communication. The control
unit notifies the terminal device of the resource pool.
[0028] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information in6
WO 2016/017099 PCT/JP2015/003566
dicating a transmission resource pool serving as a radio resource available for
transmission in device-to-device communication and a retransmission resource pool
serving as a radio resource available for retransmission in device-to-device communication;
and a control unit configured to notify a terminal device of the transmission
resource pool and the retransmission resource pool.
[0029] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
a transmission resource pool serving as a radio resource available for
transmission in device-to-device communication and a retransmission resource pool
serving as a radio resource available for retransmission in device-to-device communication;
and a control unit configured to control device-to-device communication of a
terminal device in a manner that the terminal device performs transmission in the
transmission resource pool in device-to-device communication and the terminal device
performs retransmission in the retransmission resource pool in device-to-device communication.
[0030] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an audio resource pool serving as a radio resource available for transmitting
audio data in device-to-device communication and another resource pool serving as a
radio resource available for transmitting another data in device-to-device communication;
and a control unit configured to notify a terminal device of the audio resource
pool and the another resource pool.
[0031] According to another exemplary embodiment of the present disclosure, there is
provided a device including: an acquisition unit configured to acquire information indicating
an audio resource pool serving as a radio resource available for transmitting
audio data in device-to-device communication and another resource pool serving as a
radio resource available for transmitting another data in device-to-device communication;
and a control unit configured to control device-to-device communication of a
terminal device in a manner that the terminal device transmits audio data in the audio
resource pool in device-to-device communication and the terminal device transmits
another data in the another resource pool in device-to-device communication.
[0032] According to another exemplary embodiment of the present disclosure, a device
includes circuitry configured that acquires information indicating one or more resource
pools serving as radio resources available for device-to-device communication, and
that notifies a terminal device of the one or more resource pools,
wherein the one or more resource pools are resource pools that are selected from
among a resource pool set including multiple resource pools. The multiple resource
pools are determined in advance as candidates for radio resources available for device7
WO 2016/017099 PCT/JP2015/003566
to-device communication.
[0033] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating one or more resource pools
serving as radio resources available for device-to-device communication, and that
controls device-to-device communication by a terminal device in at least one resource
pool among the one or more resource pools. The one or more resource pools are
resource pools that are selected from among a resource pool set including multiple
resource pools, which are determined in advance as candidates for radio resources
available for device-to-device communication.
[0034] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating one or more resource pools
serving as radio resources available for device-to-device communication, and notifies a
terminal device of the one or more resource pools in a predetermined resource pool.
[0035] According to another exemplary aspect of the present disclosure, a device includes
circuitry that acquires information indicating one or more resource pools serving as
radio resources available for device-to-device communication from information
received by a terminal device in a predetermined resource pool, and controls deviceto-
device communication by the terminal device in at least one resource pool among
the one or more resource pools.
[0036] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication, and notifies
a terminal device of the change in a primary resource pool among one or more
resource pools serving as radio resources available for device-to-device communication.
[0037] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication from information
received by a terminal device in a primary resource pool among one or more
resource pools serving as radio resources available for device-to-device communication,
and controls device-to-device communication by the terminal device in at
least one resource pool in accordance with the change.
[0038] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a change in a resource pool
serving as a radio resource available for device-to-device communication, and notifies
a terminal device of the change by at least one of reporting of system information indicating
the change and separate signaling.
[0039] According to another exemplary embodiment of the present disclosure, a device
8
WO 2016/017099 PCT/JP2015/003566
includes circuitry that acquires information indicating an in-coverage resource pool
serving as a radio resource available for device-to-device communication within a
network coverage area and an out-of-coverage resource pool serving as a radio
resource available for device-to-device communication outside of the network
coverage area.
[0040] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an in-coverage resource pool
serving as a radio resource available for device-to-device communication within a
network coverage area and an out-of-coverage resource pool serving as a radio
resource available for device-to-device communication outside of the network
coverage area, and notifies a terminal device of the in-coverage resource pool and the
out-of-coverage resource pool.
[0041] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a resource pool group that is
used by a synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication, and notifies a
terminal device of the resource pool group.
[0042] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a resource pool group that is
used by a synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication, and controls
device-to-device communication by a terminal device in a manner that the terminal
device omits synchronization based on synchronization information transmitted in at
least one resource pool included in the resource pool group.
[0043] According to another exemplary embodiment, a device includes circuitry that
acquires information indicating an application of device-to-device communication that
is performed in each of one or more resource pools serving as radio resources available
for device-to-device communication, and notifies a terminal device of the application.
[0044] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an application of deviceto-
device communication that is performed in each of one or more resource pools
serving as radio resources available for device-to-device communication; and controls
device-to-device communication by a terminal device in a manner that the terminal
device performs device-to-device communication in a desired application in a resource
pool in which device-to-device communication is performed in the desired application
among the one or more resource pools.
[0045] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a desired application of device9
WO 2016/017099 PCT/JP2015/003566
to-device communication of a terminal device, and notifies the terminal device of one
or more resource pools in which device-to-device communication is performed in the
desired application and which are one or more resource pools serving as radio
resources available for device-to-device communication.
[0046] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a desired application of deviceto-
device communication of a terminal device, notifies a base station or another
terminal device of the desired application, and controls device-to-device communication
in the desired application by the terminal device in at least one resource pool
among one or more resource pools of which the base station or the other terminal
device notifies the terminal device. The one or more resource pools are radio resources
available for device-to-device communication and are resource pools in which deviceto-
device communication is performed in the desired application.
[0047] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating the number of terminal devices
configured to perform device-to-device communication, selects a resource pool serving
as a radio resource available for device-to-device communication based on the number
of terminal devices configured to perform device-to-device communication, and
notifies the terminal device of the resource pool.
[0048] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a transmission resource pool
serving as a radio resource available for transmission in device-to-device communication
and a retransmission resource pool serving as a radio resource available for retransmission
in device-to-device communication, and notifies a terminal device of the
transmission resource pool and the retransmission resource pool.
[0049] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating a transmission resource pool
serving as a radio resource available for transmission in device-to-device communication
and a retransmission resource pool serving as a radio resource available for retransmission
in device-to-device communication, and that controls device-to-device
communication of a terminal device in a manner that the terminal device performs
transmission in the transmission resource pool in device-to-device communication and
the terminal device performs retransmission in the retransmission resource pool in
device-to-device communication.
[0050] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an audio resource pool serving
as a radio resource available for transmitting audio data in device-to-device communication
and another resource pool serving as a radio resource available for
10
WO 2016/017099 PCT/JP2015/003566
transmitting another data in device-to-device communication, and notifies a terminal
device of the audio resource pool and the another resource pool.
[0051] According to another exemplary embodiment of the present disclosure, a device
includes circuitry that acquires information indicating an audio resource pool serving
as a radio resource available for transmitting audio data in device-to-device communication
and another resource pool serving as a radio resource available for
transmitting another data in device-to-device communication, and that controls deviceto-
device communication of a terminal device in a manner that the terminal device
transmits audio data in the audio resource pool in device-to-device communication and
the terminal device transmits another data in the another resource pool in deviceto-
device communication.
Advantageous Effects of Invention
[0052] According to one or more of embodiments of the present disclosure described above,
it is possible to reduce a load necessary for a terminal device to recognize the radio
resources available for D2D communication. Also, the above effects are not necessarily
limited, but along with the effects or instead of the effects, any effect shown in
this specification or other effects that may be understood from this specification may
be achieved.
Brief Description of Drawings
[0053] [fig.l]FIG. 1 is a first explanatory diagram illustrating a specific example of a use case
of D2D communication.
[fig.2]FIG. 2 is a second explanatory diagram illustrating a specific example of a use
case of D2D communication.
[fig.3]FIG. 3 is an explanatory diagram illustrating exemplary timings of a PSS and an
SSS in FDD.
[fig.4]FIG. 4 is an explanatory diagram illustrating exemplary timings of a PSS and an
SSS in TDD.
[fig.5]FIG. 5 is an explanatory diagram illustrating a radio frame and subframes in a
cellular system.
[fig.6]FIG. 6 is an explanatory diagram illustrating an exemplary resource pool.
[fig.7]FIG. 7 is an explanatory diagram illustrating an example of a signal and information
transmitted in a resource pool.
[fig.8]FIG. 8 is an explanatory diagram illustrating an example of a schematic configuration
of a communication system according to an embodiment of the present
disclosure.
[fig.9]FIG. 9 is a block diagram illustrating an exemplary configuration of a base
station according to the embodiment.
11
WO 2016/017099 PCT/JP2015/003566
[fig. 10] FIG. 10 is a block diagram illustrating an exemplary configuration of a first
terminal device according to the embodiment.
[fig. 11]FIG. 11 is a block diagram illustrating an exemplary configuration of a second
terminal device according to the embodiment.
[fig.l2]FIG. 12 is an explanatory diagram illustrating an exemplary resource pool set.
[fig.l3]FIG. 13 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a first embodiment.
[fig.l4]FIG. 14 is a sequence diagram schematically illustrating a first exemplary flow
of a second process according to the first embodiment.
[fig.l5]FIG. 15 is a sequence diagram schematically illustrating a second exemplary
flow of a second process according to the first embodiment.
[fig.l6]FIG. 16 is a sequence diagram schematically illustrating an exemplary flow of
a process according to a second embodiment.
[fig.l7]FIG. 17 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a third embodiment.
[fig.l8]FIG. 18 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the third embodiment.
[fig.l9]FIG. 19 is a sequence diagram schematically illustrating an exemplary flow of
a third process according to the third embodiment.
[fig.20]FIG. 20 is a flowchart schematically illustrating an exemplary flow of a process
according to a fourth embodiment.
[fig.21]FIG. 21 is an explanatory diagram illustrating a first example of a resource pool
group.
[fig.22]FIG. 22 is an explanatory diagram illustrating a second example of a resource
pool group.
[fig.23]FIG. 23 is a sequence diagram schematically illustrating an exemplary flow of
a first process according to a fifth embodiment.
[fig.24]FIG. 24 is a sequence diagram schematically illustrating an exemplary flow of
a second process according to the fifth embodiment.

Claim 1]
[Claim 2]
[Claim 3]
[Claim 4]
[Claim 5]
[Claim 6]
[Claim 7]
[Claim 8]
[Claim 9]
Claims
A device comprising:
circuitry configured to
acquire information indicating one or more resource pools serving as
radio resources available for device-to-device communication; and
notify a terminal device of the one or more resource pools,
wherein the one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource
pools, which are determined in advance as candidates for radio
resources available for device-to-device communication.
The device according to claim 1, wherein the device is a base station, a
base station device for the base station, or a module for the base station
device.
The device according to claim 2, wherein the circuitry is further
configured to notify the terminal device of the one or more resource
pools by reporting system information indicating the one or more
resource pools.
The device according to claim 1, wherein the device is a terminal
device or a module for the terminal device.
The device according to claim 4, wherein the circuitry is further
configured to notify the terminal device of the one or more resource
pools in each of the one or more resource pools.
The device according to claim 4, wherein the circuitry is further
configured to notify the terminal device of the one or more resource
pools in a predetermined resource pool included in the resource pool
set.
The device according to claim 4, wherein the circuitry is configured to
control transmission of synchronization information in each of the one
or more resource pools.
The device according to claim 1,
wherein each of the multiple resource pools includes identification information
for identifying itself, and
wherein the circuitry is further configured to notify the terminal device
of the one or more resource pools by transmission of the identification
information of each of the one or more resource pools.
A device comprising:
circuitry configured to
127
WO 2016/017099 PCT/JP2015/003566
[Claim 10]
[Claim 11]
[Claim 12]
[Claim 13]
[Claim 14]
acquire information indicating one or more resource pools serving as
radio resources available for device-to-device communication; and
control device-to-device communication by a terminal device in at least
one resource pool among the one or more resource pools,
wherein the one or more resource pools are resource pools that are
selected from among a resource pool set including multiple resource
pools, which are determined in advance as candidates for radio
resources available for device-to-device communication.
The device according to claim 9, wherein the one or more resource
pools are resource pools of which a base station or another terminal
device notifies the terminal device.
The device according to claim 10,
wherein the information indicating the one or more resource pools is information
that is transmitted along with synchronization information by
the another terminal device in each of the one or more resource pools,
and
wherein the circuitry is further configured to acquire the information
indicating the one or more resource pools from information received by
the terminal device in the resource pool in which the synchronization
information is detected by the terminal device and which is included in
the resource pool set.
The device according to claim 10,
wherein the one or more resource pools are resource pools of which the
another terminal device notifies the terminal device in a predetermined
resource pool included in the resource pool set, and
wherein the circuitry is further configured to acquire the information
indicating the one or more resource pools from information received by
the terminal device in the predetermined resource pool.
A device comprising:
circuitry configured to
acquire information indicating one or more resource pools serving as
radio resources available for device-to-device communication; and
notify a terminal device of the one or more resource pools in a predetermined
resource pool.
A device comprising:
circuitry configured to
acquire information indicating one or more resource pools serving as
radio resources available for device-to-device communication from in128
WO 2016/017099 PCT/JP2015/003566
[Claim 15]
[Claim 16]
[Claim 17]
[Claim 18]
[Claim 19]
[Claim 20]
formation received by a terminal device in a predetermined resource
pool; and
control device-to-device communication by the terminal device in at
least one resource pool among the one or more resource pools.
A device comprising:
circuitry configured to
acquire information indicating a change in a resource pool serving as a
radio resource available for device-to-device communication; and
notify a terminal device of the change in a primary resource pool
among one or more resource pools serving as radio resources available
for device-to-device communication.
The device according to claim 15, wherein the change includes deleting
the resource pool, adding the resource pool, changing the primary
resource pool, or changing an application of device-to-device communication
performed in the resource pool.
The device according to claim 15, wherein the circuitry is further
configured to notify the terminal device of the primary resource pool.
The device according to claim 15,
wherein the device is another terminal device different from the
terminal device or a module for the another terminal device,
wherein the one or more resource pools are resource pools selected by
the another terminal device, and
wherein the primary resource pool is a resource pool unique to the
another terminal device.
The device according to claim 15,
wherein the device is another terminal device different from the
terminal device or a module for the another terminal device,
wherein the one or more resource pools are resource pools selected by a
base station, and
wherein the primary resource pool is a resource pool unique to the base
station.
A device comprising:
circuitry configured to
acquire information indicating a change in a resource pool serving as a
radio resource available for device-to-device communication from information
received by a terminal device in a primary resource pool
among one or more resource pools serving as radio resources available
for device-to-device communication; and
129
WO 2016/017099 PCT/JP2015/003566
[Claim 21]
[Claim 22]
[Claim 23]
[Claim 24]
[Claim 25]
[Claim 26]
[Claim 27]
[Claim 28]
control device-to-device communication by the terminal device in at
least one resource pool in accordance with the change.
A device comprising:
circuitry configured to
acquire information indicating a change in a resource pool serving as a
radio resource available for device-to-device communication; and
notify a terminal device of the change by at least one of reporting of
system information indicating the change and separate signaling.
A device comprising:
circuitry configured to
acquire information indicating an in-coverage resource pool serving as
a radio resource available for device-to-device communication within a
network coverage area and an out-of-coverage resource pool serving as
a radio resource available for device-to-device communication outside
of the network coverage area.
The device according to claim 22, wherein the circuitry is further
configured to control device-to-device communication by the terminal
device in a manner that the terminal device transmits a signal of same
information in both of the in-coverage resource pool and the outof-
coverage resource pool.
A device comprising:
circuitry configured to
acquire information indicating a resource pool group that is used by a
synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication;
and
notify a terminal device of the resource pool group.
The device according to claim 24, wherein the synchronized terminal
device includes a terminal device that is synchronized based on synchronization
information transmitted by one transmission source.
The device according to claim 25, wherein the synchronized terminal
device further includes a terminal device that is synchronized based on
synchronization information transmitted by another transmission source
synchronized with the one transmission source.
The device according to claim 25, wherein the other transmission
source includes a transmission source configured to relay the synchronization
information transmitted by the one transmission source.
The device according to claim 24, wherein the resource pool group
130
WO 2016/017099 PCT/JP2015/003566
[Claim 29]
[Claim 30]
[Claim 31]
[Claim 32]
[Claim 33]
[Claim 34]
includes two or more resource pools serving as radio resources
available for device-to-device communication.
The device according to claim 24,
wherein the device is a base station, a base station device for the base
station, or a module for the base station device, and
wherein the circuitry is further configured to notify the terminal device
of the resource pool group by reporting system information indicating
the resource pool group.
The device according to claim 24,
wherein the device is a terminal device or a module for the terminal
device, and
wherein the circuitry is further configured to notify a terminal device of
the resource pool group in at least one resource pool included in the
resource pool group.
A device comprising:
circuitry configured to
acquire information indicating a resource pool group that is used by a
synchronized terminal device and includes one or more resource pools
serving as radio resources available for device-to-device communication;
and
control device-to-device communication by a terminal device in a
manner that the terminal device omits synchronization based on synchronization
information transmitted in at least one resource pool
included in the resource pool group.
A device comprising:
circuitry configured to
acquire information indicating an application of device-to-device communication
that is performed in each of one or more resource pools
serving as radio resources available for device-to-device communication;
and
notify a terminal device of the application.
The device according to claim 32, wherein the application includes an
urgent application and a non-urgent application, an application for
public safety and an application other than one for public safety, or an
out-of-coverage application and an in-coverage application, an audio
application and non-audio application, normal transmission and retransmission.
The device according to claim 32,
131
WO 2016/017099 PCT/JP2015/003566
[Claim 35]
[Claim 36]
[Claim 37]
[Claim 38]
[Claim 39]
wherein the device is a base station, a base station device for the base
station, or a module for the base station device, and
wherein the circuitry is further configured to notify the terminal device
of the application by reporting system information indicating the application.
The device according to claim 32,
wherein the device is a terminal device or a module for the terminal
device, and
wherein the circuitry is further configured to notify a terminal device of
the application in the resource pool serving as a radio resource
available for device-to-device communication.
A device comprising:
circuitry configured to
acquire information indicating an application of device-to-device communication
that is performed in each of one or more resource pools
serving as radio resources available for device-to-device communication;
and
control device-to-device communication by a terminal device in a
manner that the terminal device performs device-to-device communication
in a desired application in a resource pool in which deviceto-
device communication is performed in the desired application
among the one or more resource pools.
A device comprising:
circuitry configured to
acquire information indicating a desired application of device-to-device
communication of a terminal device; and
notify the terminal device of one or more resource pools in which
device-to-device communication is performed in the desired application
and which are one or more resource pools serving as radio resources
available for device-to-device communication.
The device according to claim 37, wherein the circuitry is further
configured to select one or more resource pools that allow deviceto-
device communication in the desired application as the one or more
resource pools in which device-to-device communication is performed
in the desired application.
The device according to claim 38, wherein the one or more resource
pools appropriate for device-to-device communication in the desired
application are one or more resource pools having a period appropriate
132
WO 2016/017099 PCT/JP2015/003566
that allow for device-to-device communication in the desired application
or the appropriate number of resource pools for that allow
device-to-device communication in the desired application.
[Claim 40] The device according to claim 37,
wherein the circuitry is further configured to
acquire information indicating a desired application of device-to-device
communication of a separate terminal device, and
notify the separate terminal device of one or more resource pools in
which device-to-device communication is performed in the desired application.
[Claim 41] The device according to claim 37, wherein the circuitry is further
configured to notify the terminal device of one or more resource pools
in which device-to-device communication is performed in the desired
application and an application of device-to-device communication
performed in the one or more resource pools.
[Claim 42] A device comprising:
circuitry configured to
acquire information indicating a desired application of device-to-device
communication of a terminal device;
notify a base station or another terminal device of the desired application;
and
control device-to-device communication in the desired application by
the terminal device in at least one resource pool among one or more
resource pools of which the base station or the other terminal device
notifies the terminal device,
wherein the one or more resource pools are radio resources available
for device-to-device communication and are resource pools in which
device-to-device communication is performed in the desired application.