JP6894396B2 - Mobile communication networks and base stations - Google Patents

Description

The present invention relates to wireless resource control for device-to-device communication of user devices in a mobile communication network.

Device-to-device (D2D: Device to Device) communication has been proposed in which user devices (UEs) of a mobile communication network communicate directly with each other without going through a base station (BS). Non-Patent Document 1 and Non-Patent Document 2 disclose radio resource control for this D2D communication. Hereinafter, the radio resource control for D2D communication disclosed in Non-Patent Document 1 and Non-Patent Document 2 will be described.

FIG. 7A shows a physical channel (downlink channel) transmitted by the BS to the UE, and FIG. 7B shows a physical channel (uplink channel) transmitted by the UE to the BS. In FIG. 7A, the PDCCH is a downlink control channel and is used to notify the UE of the radio resource used by the BS. Further, in FIG. 7A, the PDSCH is a downlink shared channel and is used for transmitting data to the UE and transmitting control information. Further, in FIG. 7B, the PUCCH is an uplink control channel and is used for the UE to request the BS to allocate radio resources and the like. Further, in FIG. 7B, the PUSCH is an uplink shared channel and is used for transmitting data from the UE to the BS and transmitting control information.

According to Non-Patent Document 1 and Non-Patent Document 2, a control channel and a shared channel are provided as physical channels for D2D communication, as in the case of downlink and uplink. The control channel for D2D communication is called a side link control channel (PSCCH: Physical Sidelink Control Channel), and the shared channel for D2D communication is called a sidelink shared channel (PSSCH: Physical Sidelink Sharp Channel). As shown in FIG. 7B, a part of PUSCH is assigned to PSCCH and PSSCH. In the following description, PSCCH and PSCH will be collectively referred to as side link channels.

In an environment in which a UE performing D2D communication exists within the service provision range of the mobile communication network, the mobile communication network manages a radio resource for D2D communication, that is, a side link channel. According to Non-Patent Document 1 and Non-Patent Document 2, the BS notifies the UE in the area by SIB (System Information Block) Type 18 which region of the PUSCH to the BS is used as the side link channel. As shown in FIG. 7A, the SIB Type 18 is transported by PDSCH. Further, in the following description, the area notified by the SIB Type 18 will be referred to as a side link radio resource pool.

According to SIB Type 18, the UE recognizes the side-link radio resource pool, but Non-Patent Document 1 describes which area (which side-link channel) of the side-link radio resource pool the UE uses for D2D communication. And Non-Patent Document 2 defines two methods, mode 1 and mode 2. Mode 2 is a mode in which the UE autonomously selects a side link channel to be used from the side link radio resource pool. On the other hand, the mode 1 is a mode in which the BS notifies each UE performing D2D communication which side link channel of the side link radio resource pool is used. This notification is carried by the DCI (Downlink Control Information) form 5 of the PDCCH shown in FIG. 7 (A). In DCI format 5, the radio resource position in the PUSCH used for D2D communication is not specified by the absolute position of the PUSCH, but is a relative position based on a predetermined position of the side link radio resource pool. specify. That is, in mode 1, the UE uses both the side link radio resource pool notified by SIB Type 18 and the relative position notified by DCI format 5 for the side link channel used by the own device for D2D communication. To identify.

3GPP, TS36.213, v14.4.0 3GPP, TS36.212, v15.0.0 3GPP, TS36.211, v14.5.0

In mode 1, since the mobile communication network specifies the side link channel used by the UE for D2D communication, interference in D2D communication can be suppressed. However, in mode 1, the notification by DCI format 5 is individually performed for each UE performing D2D communication, and therefore, as the number of UEs performing D2D communication increases, the radio resource used for this notification in the PDCCH The amount increases. The PDCCH is also used to control communication between the UE and the BS, and the amount of radio resources thereof is basically constant. Therefore, as the number of UEs performing D2D communication increases, the amount of radio resources of the PDCCH becomes insufficient. However, the necessary notification to the UE will not be given at the right time. Although Non-Patent Document 3 discloses that a part of PDSCH is used as PDCCH as a countermeasure against PDCCH depletion, the amount of radio resources of PDSCH is reduced, which affects data transmission to the UE. To exert.

On the other hand, in mode 2, the UE autonomously selects the side link channel to be used from the side link radio resource pool and does not require notification by DCI format 5, so that the problem in mode 1 does not occur. However, interference in D2D communication can occur.

The present invention provides a technique for suppressing an increase in the amount of radio resources for notifying radio resources used in inter-device communication.

According to one aspect of the present invention, the mobile communication network is classified into a first user device and a second user device, which are located in a cell provided by the mobile communication network and transmit a plurality of user devices in inter-device communication. The means and the user device classified into the first user device are designated as wireless resources to be used in the inter-device communication, and the user device classified into the second user device is the radio used in the inter-device communication. The classification means includes a notification means for notifying a pool of wireless resources for selection by a user device that has classified resources into the second user device, and the classification means includes all of the plurality of user devices as the second user device. When the duplication probability is larger than the threshold value, the duplication probability is calculated by classifying a predetermined number of user devices into the first user device, until the duplication probability becomes equal to or less than the threshold value. When the overlap probability becomes equal to or less than the threshold value, the unclassified user device is classified into the second user device, and the overlap probability is the same as that of the user device classified into the second user device from the pool of the radio resources. wherein the probability der Rukoto to select a radio resource.

According to the present invention, it is possible to suppress an increase in the amount of radio resources for notifying the radio resources used in inter-device communication.

The block diagram of the mobile communication system by one Embodiment. A flowchart of a classification process according to an embodiment. The figure which shows the classification result by one Embodiment. A sequence diagram for side link channel notification according to an embodiment. The figure which shows the cell and the small cell by one Embodiment. A block diagram of a server device and a base station according to an embodiment. The figure which shows the physical channel of the uplink and the downlink.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples, and the present invention is not limited to the contents of the embodiments. Further, in each of the following figures, components that are not necessary for the description of the embodiment will be omitted from the drawings.

<First Embodiment>
FIG. 1 is a configuration diagram of a mobile communication system according to the present embodiment. The mobile communication network includes a core network 2 and a BS3. BS3 is connected to the core network 2. The BS3 also provides a service to the UE 4 in the cell 5. The core network 2 has a server device 1. The server device 1 recognizes which UE 4 and which UE 4 performs D2D communication by prior negotiation between the UE 4 and the mobile communication network.

In the present embodiment, the server device 1 classifies the UE 4 which is located in the cell 5 where the BS3 provides the service and transmits in the D2D communication into the first terminal and the second terminal. Here, the first terminal is a UE 4 in which the side link channel used for D2D communication is designated by the mobile communication network, and the second terminal autonomously uses the side link channel used for D2D communication. UE4 to be selected. The side link channel that can be selected by the second terminal is a side link channel that is not assigned to the first terminal among the side link channels included in the side link radio resource pool. In the following description, it is assumed that the UE 4 that is in the cell provided by BS3 and that transmits in D2D communication is referred to as a classification target UE.

FIG. 2 is a flowchart of the classification process for the classification target UE executed by the server device 1. In S10, the server device 1 calculates the overlap probability Pr. Here, the duplication probability Pr is the probability that the UE 4 classified as the second terminal selects the same side link channel from the side link radio resource pool. In S11, the duplication probability Pr is calculated assuming that all the classification target UEs are classified into the second terminal. Assuming that the number of UEs to be classified is n and the number of side link channels reserved for the second terminal in the side link radio resource pool is r, the overlap probability Pr is calculated by the following equation (1).
^{Pr = 1-rPn / (r} n) (r ≧ n), Pr = 1 (r <n) (1)

In S11, the server device 1 determines whether or not the overlap probability Pr is equal to or greater than a predetermined threshold value. The threshold value is set to an allowable upper limit value of the probability that different UEs 4 select the same side link radio resource. If the duplication probability Pr is less than the threshold value, the server device 1 classifies all the classification target UEs into the second terminal in S16 and ends the process. On the other hand, when the duplication probability Pr is equal to or higher than the threshold value, the server device 1 determines the UE 4 to be classified into the first terminal from the classification target UE in S12. In S12, the number of UEs 4 classified into the first terminal can be any number of 1 or more. In the present embodiment, in S12, the number of UEs 4 to be classified into the first terminal is set to 1, an arbitrary one UE4 is selected from the classification target UEs, and the selected UE4 is classified into the first terminal. The UE 4 classified as the first terminal is excluded from the classification target UEs. Then, the server device 1 recalculates the overlap probability Pr in S13 and compares it with the threshold value in S14. If the overlap probability Pr is equal to or greater than the threshold value in S14, the server device 1 repeats the process from S12 until the overlap probability Pr becomes less than the threshold value. Then, when the overlap probability Pr becomes less than the threshold value in S14, the server device 1 classifies the classification target UE (unclassified UE) at that time into the second terminal in S15 and ends the process.

FIG. 3A shows how the server device 1 classifies the classification target UEs into the first terminal and the second terminal. According to FIG. 3A, UE # A1, UE # A2, ... Are classified into the first terminal, and UE # Z1, UE # Z2, ... Are classified into the second terminal. For example, when the UE that performs D2D communication in the BS3 is classified into the first terminal or the second terminal, the server device 1 transmits the classification result to the BS3.

The BS3 allocates a side link channel to each UE 4 classified as the first terminal. Further, the BS3 determines the side link channel that has not been assigned to the UE 4 classified as the first terminal in the side link radio resource pool. Then, as shown in S20 of FIG. 4, the BS3 is a side link channel that is not assigned to the UE 4 classified as the first terminal among the side link radio resource pool and the side link channel included in the side link radio resource pool. The selectable channel information indicating the above is notified by SIB Type 18 of PDSCH. Further, as shown in S21, the BS3 notifies the side link channel assigned to each UE 4 classified as the first terminal by the DCI format 5 of the PDCCH. For example, in S23 and S24, the UE 4 determines whether the own device is the first terminal or the second terminal based on the contents specified in the DCI format 5. Specifically, if the side link channel used by the own device is specified in DCI form 5, it is determined that the own device is classified as the first terminal, and the side link channel used by the own device is determined in DCI form 5. If it is not specified, it is determined that the own device is classified as the second terminal. Then, the UE 4 classified as the first terminal transmits data for D2D communication using the designated side link channel in S25. Further, the UE 4 classified as the second terminal transmits data for D2D communication using the side link channel selected from the selectable channels in S26.

As described above, the UE 4 is classified into the first terminal or the second terminal so that the overlap probability Pr is less than the threshold value. Therefore, while suppressing the interference of D2D communication by using the same side link channel, the number of UEs 4 that need to specify the side link channel in DCI format 5 is reduced, and thereby the radio for notifying the side link channel. It is possible to suppress an increase in the amount of resources.

<Second embodiment>
Subsequently, the second embodiment will be described focusing on the differences from the first embodiment. In the first embodiment, the server device 1 classifies any UE 4 of the classification target UE into the first terminal in S12 of FIG. In the present embodiment, the position-related information related to the position of the UE 4 is used for classification to the first terminal. Specifically, the UE 4 to be first classified into the first terminal is arbitrarily determined. Then, when the UE 4 already classified into the first terminal exists, the UE 4 to be classified into the first terminal is selected from the UE 4 whose distance from each of the UE 4 already classified into the first terminal is equal to or larger than a predetermined value among the classification target UEs. .. If there is no UE 4 whose distance to each of the UEs 4 classified into the first terminal is equal to or greater than a predetermined value, the UE 4 having the largest average distance to each of the UEs 4 already classified into the first terminal is classified into the first terminal. To do. By selecting the UE to be classified into the first terminal in this way, as a result, the average distance between the UEs 4 to be classified into the second terminal can be increased. Therefore, even if the UE 4 classified as the second terminal selects the same side link channel in the overlapping period, the probability of interference can be suppressed.

For example, the position-related information of the UE 4 can be acquired by the UE 4 by GPS or the like. In this case, the server device 1 can acquire this position-related information directly from the UE 4 or indirectly via another device. Further, when the BS3 can determine the rough position of the UE 4 based on the strength and direction of the signal received from the UE 4, the BS3 can determine the position of the UE 4. In addition, as described in the third embodiment, CQI and area information to the small cell can also be used as position-related information.

<Third Embodiment>
In the first embodiment and the second embodiment, the UE 4 classified as the first terminal is individually notified of the side link radio resource to be used by the DCI format 5. In the present embodiment, the UEs 4 classified into the first terminal are further grouped. The grouping is performed so that the transmission signal for D2D communication performed by a certain UE 4 does not affect the D2D communication of another UE 4 belonging to the same group. FIG. 3B shows a state in which a part of UE 4 classified into the first terminal is grouped. According to FIG. 3B, the two UEs 4 of UE # A1 and UE # A2 belong to group 1 (G1), and the three UEs 4 of UE # B1, UE # B2, and UE # B3 belong to group 2 (G2). ) Belongs to. The UE 4 classified into the other first terminal does not belong to the group.

When the server device 1 performs grouping, the server device 1 notifies BS3 of the result of grouping. The BS3 assigns a group identifier (GID) to each group and notifies the UE 4 belonging to the group of the GID of the group. This notification can use SIB Type 20. The SIB Type 20 is for notifying the UE of G-RNTI (Group-Radio Network Strength ID) for multicast communication, and the G-RNTI can notify each UE 4 of the GID.

The BS3 individually notifies the UE 4 which is classified as the first terminal and does not belong to the group of the side link channel to be used. On the other hand, UE4, which is classified as the first terminal and belongs to the group, is notified of the side link channels to be collectively used by GID. UE4 belonging to the same group performs D2D communication using the same side link channel, but as described above, the group is selected so that the influence is small even if the same side link channel is used, which is a big problem. Does not occur.

The server device 1 is grouped based on the position-related information of the UE 4. For example, as described in the second embodiment, the server device 1 can use the latitude and longitude acquired by the UE 4 by GPS or the like and transmitted to the mobile communication network as position-related information. Further, for example, as described in the second embodiment, the server device 1 can use the position of the UE 4 estimated based on the strength and direction of the signal received from the UE 4 by the BS 3 as the position-related information. Further, the server device 1 can use the CQI (Channel Quality Indicator) notified by the UE 4 to the mobile communication network as the location-related information. CQI is a value based on the received power of the reference signal received by the UE 4 from the BS3. Here, in general, the UE 4 closer to the BS3 has a higher reception power of the reference signal, and the UE 4 farther from the BS3 has a lower reception power of the reference signal. Therefore, it can be considered that a large difference in CQI between the two UEs 4 indicates that the two UEs 4 are separated from each other. Therefore, the server device 1 can make the UE 4 in which the difference in CQI is equal to or larger than a predetermined value into the same group.

Further, the server device 1 can use the territorial information of the UE 4 to the small base station (SBS) installed in the cell 5 as the position-related information. As shown in FIG. 5, a plurality of SBSs may be provided in the cell 5 provided by the BS3. In FIG. 5, four SBSs are provided, and each SBS provides small cells 51, 52, 53, and 54. Since the UE 4 communicating with the SBS is located in the small cell provided by the SBS and the coverage of the SBS is very short, the mobile communication network is such that the UE 4 communicating with the SBS is in the vicinity of the SBS. It can be determined that there is. For example, assuming that the shortest distances of any two small cells of the small cells 51, 52, 53 and 54 in FIG. 5 are separated so as not to affect the D2D communication, the small cells 51, 52, 53 and 54 The four UEs 4 in the area can be grouped together.

Even in a configuration in which the server device 1 first determines the classification to the first terminal and then groups the UEs 4 classified into the first terminals, the first server device 1 takes into consideration the grouping of the UEs 4. It may be configured to determine the classification to the terminal. In the latter case, in S12 of FIG. 2, the server device 1 determines the UE 4 that can be grouped into one group and can maximize the number belonging to the group, and classifies the determined UE 4 into the first terminal. In the server device 1, the first terminal determined here is one group. After that, when S14 is Yes, in the next S12 as well, the UE 4 that can be grouped into one group among the UEs to be classified and that can maximize the number belonging to the group is determined, and the determined UE 4 is determined. Are classified into the first terminal as one group. After that, the process is repeated until the determination in S14 becomes No. In S12, if there is no UE to be classified into one group, one UE 4 to be classified into the first terminal is determined by an arbitrary method. This UE 4 is a UE 4 that does not belong to the group.

With the above configuration, the side link channels can be collectively specified for the UEs 4 belonging to the group, and thus an increase in the amount of radio resources for notifying the side link channels can be suppressed.

Although FIG. 1 shows only one BS3 and one server device 1, there are a plurality of BS3s in the communication network, and the server device 1 performs the above-mentioned classification process for each of the plurality of BS3s. And notify each BS3 of the classification result. When grouping the first terminals, the server device 1 also notifies each BS3 of the grouping result. Further, a plurality of server devices 1 may be provided, and each server device 1 may be configured to perform classification processing for one or more predetermined BS3s and grouping processing as necessary. Further, one BS3 and one server device 1 can be associated with each other on a one-to-one basis, and in this case, the function of the server device 1 described above can be incorporated into the BS3. Further, the function of the server device 1 can be incorporated on the same computer as the other functions of the core network 2.

FIG. 6 is a configuration diagram of the server device 1 and BS3. The classification unit 11 of the server device 1 classifies the UE 4 located in the cell 5 of the BS3 into a first terminal and a second terminal. Further, when grouping the first terminals, the classification unit 11 has a grouping unit (not shown). As described above, the grouping unit groups based on the position-related information related to the position of each UE 4. The position-related information can be, for example, the latitude and longitude acquired by the UE 4 by GPS and notified to the server device 1 via the BS3. Further, the position of the BS3 estimated from the signal strength and direction received from the UE 4 can be set. Further, it can be a CQI that each UE 4 notifies BS3. Further, it can be used as the information on the presence of the UE 4 in the small cell in the cell provided by the BS3. The grouping unit is configured so that necessary location-related information can be acquired from each functional block of the mobile communication network. The notification unit 12 notifies BS3 of the classification result by the classification unit 11. Further, when the first terminals are grouped, the notification unit 12 also notifies the BS3 of the result of this grouping.

When the communication unit 34 of the BS3 receives the classification result from the server device 1, the communication unit 34 outputs the result to the resource allocation unit 33. The resource allocation unit 33 individually allocates a side link channel to the UE 4 classified as the first terminal. When the first terminals are grouped, a side link channel is assigned to the UE belonging to the group. The notification unit 32 notifies the side link channels that can be used for D2D communication and the side link channels that are not assigned to the first terminal among all the side link channels by SIB Type 18. The side link channel not assigned to the first terminal is a subset of all side link channels. Further, the notification unit 32 designates the UE 4 classified as the first terminal individually in the DCI format 5, that is, the side link used in the unicast. When the first terminals are grouped, the same side link used by the UE is specified by multicast, that is, by using GID for the UEs belonging to the group.

When the server device 1 is incorporated in the BS3, the classification unit 11 is provided in the BS3. Further, in the UE 4 according to the present embodiment, the first information indicating all side link channels that can be used in the device-to-device communication, the second information indicating a subset of all side link channels, and the communication between the UE 4 and the device are announced by the BS3. When the third information indicating the relationship with the wireless resource used in the above, the receiving unit receiving the receiver, and the relationship between the own device and the wireless resource is indicated by the third information, the wireless resource indicated by the third information is used. When the device-to-device communication is performed and the relationship between the own device and the wireless resource is not shown in the third information, the wireless resource is selected from the subset indicated by the second information, and the device uses the selected wireless resource. It is equipped with a communication unit that performs inter-communication.

The server device 1 according to the present invention can be realized by a program that causes the computer to function as the server device 1 described above when executed by one or more processors of the computer. Similarly, the BS3 according to the present invention can be realized by a program that causes the BS to function as the BS3 described above when executed by one or more processors of the BS. Further, the UE 4 according to the present invention can be realized by a program that causes the UE to function as the UE 4 described above when executed by one or more processors of the UE. These computer programs are stored in a computer-readable storage medium or can be distributed over a network.

11: Classification section, 33: Resource allocation section, 32: Notification section

Claims (8)

A classification means for classifying a plurality of user devices that are located in a cell provided by a mobile communication network and transmit in inter-device communication into a first user device and a second user device.
The wireless resources used in the inter-device communication are specified for the user devices classified into the first user device, and the wireless resources used in the inter-device communication are specified in the user devices classified into the second user device. A notification means for notifying a pool of radio resources for selection by a user device classified as a second user device, and
Equipped with a,
When the duplication probability when all of the plurality of user devices are classified into the second user device is larger than the threshold value, the classification means classifies a predetermined number of user devices into the first user device and the duplication probability. Is repeated until the overlap probability becomes equal to or less than the threshold value, and when the overlap probability becomes equal to or less than the threshold value, the unclassified user device is classified into the second user device.
The overlapping probability, the mobile communication network to which the user equipment classified to the second user equipment, wherein the probability der Rukoto select the same radio resources from a pool of radio resources. The mobile communication network according to claim 1 , wherein the classification means determines the predetermined number of user devices to be classified into the first user device based on the position-related information of the unclassified user devices. Further, it is provided with an allocation means for allocating the radio resources used by the user equipment classified into the first user equipment from the radio resources that can be used for the inter-device communication.
The mobile communication network according to claim 1 or 2 , wherein the pool of wireless resources is a pool of wireless resources that can be used for inter-device communication, excluding the wireless resources allocated to the first user apparatus. Further, it is provided with a grouping means for grouping the user devices classified into the first user device based on the position-related information of the user device.
The allocation means allocates wireless resources to the group of the user devices classified into the first user device and belongs to the group.
The mobile communication network according to claim 3 , wherein the notification means designates the same radio resource assigned to the group to the user devices belonging to the group among the user devices classified into the first user device. A classification means for classifying a plurality of user devices that are located in a cell provided by a mobile communication network and transmit in inter-device communication into a first user device and a second user device.
The wireless resources used in the inter-device communication are specified for the user devices classified into the first user device, and the wireless resources used in the inter-device communication are specified in the user devices classified into the second user device. A notification means for notifying a pool of radio resources for selection by a user device classified as a second user device, and
An allocation means for allocating wireless resources used by the user equipment classified into the first user equipment from the wireless resources that can be used for inter-device communication, and
With
Said classification means, duplicate the probability is larger than the threshold value in the case of classifying all of the plurality of user equipment to the second user equipment, a user device that can be grouped based on the location-related information of the user equipment unclassified If there is a user device that can be grouped, the user devices that can be grouped are classified into the first user device as one group, and if there is no user device that can be grouped, an unclassified predetermined number. The user device is classified into the first user device, and after the first user device is classified, the calculation of the duplication probability is repeated until the duplication probability is equal to or less than the threshold value, and the duplication probability is equal to or less than the threshold value. The user device that has not been classified when becomes the second user device is classified into the second user device.
The allocation means allocates wireless resources to the group of the user devices classified into the first user device and belongs to the group.
The notification means designates the same radio resource assigned to the group to the user device belonging to the group among the user devices classified into the first user device.
The pool of radio resources, all SANYO excluding the radio resources allocated to the first user equipment from the radio resource that can be used for communication between the devices,
The overlapping probability, the second user equipment mobile communications network characterized probability der Rukoto the user equipment selects the same radio resources from a pool of radio resources which are classified into. The position-related information of the user device includes the position information acquired by the user device, the position information of the user device estimated by the base station communicating with the user device of the mobile communication network, and the user device receiving from the base station. value based on the received power of the reference signal, and, according to claim 2, characterized in that it comprises at least one of the area information of the user apparatus to the small cell small base station installed in said cell is provided Or the mobile communication network according to 5. A mobile communication network having a base station and a server device.
The server device is a classification means that is located in a cell provided by the base station and classifies a plurality of user devices that perform transmission in inter-device communication into a first user device and a second user device.
A result notification means for notifying the base station of the classification result by the classification means, and
Is equipped with
The base station
According to the classification result by the classification means notified from the result notification means, the wireless resources used in the inter-device communication are designated for the user devices classified into the first user device, and the user devices are classified into the second user device. The user device is provided with a notification means for notifying a pool of wireless resources for the user device classified into the second user device to select the wireless resource used in the inter-device communication .
When the duplication probability when all of the plurality of user devices are classified into the second user device is larger than the threshold value, the classification means classifies a predetermined number of user devices into the first user device and the duplication probability. Is repeated until the overlap probability becomes equal to or less than the threshold value, and when the overlap probability becomes equal to or less than the threshold value, the unclassified user device is classified into the second user device.
The overlapping probability, the mobile communication network to which the user equipment classified to the second user equipment, wherein the probability der Rukoto select the same radio resources from a pool of radio resources. A base station for mobile communication networks
A classification means for classifying a plurality of user devices that are located in the cell provided by the base station and transmit in inter-device communication into a first user device and a second user device.
The wireless resources used in the inter-device communication are specified for the user devices classified into the first user device, and the wireless resources used in the inter-device communication are specified in the user devices classified into the second user device. A notification means for notifying a pool of radio resources for selection by a user device classified as a second user device, and
Equipped with a,
When the duplication probability when all of the plurality of user devices are classified into the second user device is larger than the threshold value, the classification means classifies a predetermined number of user devices into the first user device and the duplication probability. Is repeated until the overlap probability becomes equal to or less than the threshold value, and when the overlap probability becomes equal to or less than the threshold value, the unclassified user device is classified into the second user device.
The overlapping probability, the base station that the user equipment classified to the second user equipment, wherein the probability der Rukoto select the same radio resources from a pool of radio resources.

Images