COMMUNICATION CONTROL METHOD, USER EQUIPMENT, PROCESSOR, COMMUNICATION SYSTEM, AND PROGRAM

Abstract

To provide a communication control method in a mobile communication system capable of side-link communication between first user equipment and second user equipment.SOLUTION: A method includes, in the case where first user equipment is set to receive intermittently from second user equipment when the first user equipment transmits an RRC (Radio Resource Control) message containing configuration information about side-link communication, the first user equipment performing a waiting process for receiving an RRC response message to the RRC message regardless of the intermittent reception setting. The method also includes, when the second user equipment receives the RRC message, transmitting, by the second user equipment, the RRC response message to the RRC message, and receiving, by the first user equipment, the RRC response message.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a communication control method for use in a mobile communication system. [Background technology]

[0002] Sidelink communication for wireless communication between user devices is defined in the standards of 3GPP (Third Generation Partnership Project) (registered trademark; the same applies below), which is a standardization project for mobile communication systems (see, for example, Non-Patent Document 1). Sidelink communication makes it possible to realize, for example, V2X (Vehicle to Everything) services including vehicle-to-vehicle (V2V) communication.

[0003] In sidelink communication, there is a case where wireless communication is performed between user equipments using resources scheduled by NG-RAN (Next Generation-Radio Access Network) (mode 1). In addition, there is a case where user equipments autonomously select resources from a resource pool to perform wireless communication in sidelink communication (mode 2).

[0004] Furthermore, when the user equipment is within the coverage of the NG-RAN, sidelink communication is supported regardless of the RRC (Radio Resource Control) state of the user equipment, and also when the user equipment is outside the coverage of the NG-RAN.

[0005] Therefore, for example, when a user equipment is within the coverage range of the NG-RAN, it can wirelessly communicate with other user equipment using scheduled resources and can autonomously select resources to wirelessly communicate, whereas when the user equipment is outside the coverage range of the NG-RAN, it autonomously selects resources to wirelessly communicate with other user equipment.

[0006] Furthermore, the sidelink communication supports unicast, groupcast and broadcast transmissions. In unicast transmission, user traffic is transmitted between a pair of peer user equipments. In groupcast transmission, user traffic is transmitted between user equipments belonging to a group in the sidelink. In broadcast transmission, user traffic is transmitted between user equipments in the sidelink. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP TS 38.300 V16.2.0 (2020-07) Summary of the Invention

[0008] A communication control method according to a first aspect is a communication control method in a mobile communication system having a first user device and a second user device, and capable of sidelink communication between the first user device and the second user device. The communication control method includes, when the first user device transmits a Radio Resource Control (RRC) message including configuration information regarding the sidelink communication, if discontinuous reception is configured between the first user device and the second user device, performing a standby process for receiving an RRC response message in response to the RRC message regardless of the setting of the discontinuous reception. The communication control method also includes, when the second user device receives the RRC message, transmitting the RRC response message in response to the RRC message, and the first user device receiving the RRC response message.

[0009] A communication control method according to a second aspect is a communication control method in a mobile communication system having a first user equipment and a second user equipment, and capable of sidelink communication between the first user equipment and the second user equipment. The communication control method includes resetting a frame number of a predetermined frame at a timing when the first user equipment transmits a first RRC message including configuration information regarding the sidelink communication, or at a timing when the second user equipment receives the first RRC message transmitted from the first user equipment. Alternatively, the communication control method includes resetting a frame number of the predetermined frame at a timing when the second user equipment transmits a second RRC message regarding completion of configuration of the sidelink communication, or at a timing when the first user equipment receives the second RRC message transmitted from the second user equipment.

[0010] A communication control method according to a third aspect is a communication control method in a mobile communication system having a first user device and a second user device, and capable of sidelink communication between the first user device and the second user device. The communication control method includes transmitting, by the first user device, an RRC message including first setting information related to a setting of discontinuous reception in the sidelink communication of the first user device and second setting information related to a setting of discontinuous reception in the sidelink communication of the second user device, and receiving, by the second user device, the RRC message.

[0011] A communication control method according to a fourth aspect is a communication control method in a mobile communication system including a base station device, a first user device and a second user device capable of wireless communication with the base station device, and capable of sidelink communication between the first user device and the second user device. The communication control method includes the first user device transmitting an RRC message including setting information related to discontinuous reception in the sidelink communication, and the second user device receiving the RRC message. The communication control method also includes the second user device transmitting to the first user device an adjustment request message requesting adjustment of a setting of discontinuous reception in the sidelink communication, or transmitting to the base station device a sidelink information message requesting a change in a setting of discontinuous reception in the sidelink communication.

[0012] A communication control method according to a fifth aspect is a communication control method in a mobile communication system including a base station device, a first user device and a second user device capable of wireless communication with the base station device, and capable of sidelink communication between the first user device and the second user device. The communication control method includes the base station device transmitting an RRC message including configuration information related to a configuration of discontinuous reception in the sidelink communication, or reporting system information including the configuration information, and the first user device and the second user device receiving the RRC message and applying the configuration of discontinuous reception in the sidelink communication. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a mobile communication system according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a user device according to an embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example of the configuration of a base station according to an embodiment. [Figure 4]FIG. 4 is a diagram illustrating an example of the configuration of a protocol stack of the user plane of the Uu interface. [Diagram 5] FIG. 5 is a diagram showing an example of the configuration of a protocol stack of the control plane of the Uu interface. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of a protocol stack of the user plane of the PC5 interface. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of a protocol stack of the control plane of the PC5 interface. [Figure 8] FIG. 8A illustrates an example of wireless communication between UEs, and FIG. 8B illustrates an operation example of the first embodiment. [Figure 9] FIG. 9A shows an example of On-duration and Off-duration, and FIG. 9B shows an example of message transmission and reception timing. [Figure 10] FIG. 10A is a diagram showing an example of message transmission and reception, and FIG. 10B is a diagram showing an example of operation of the first embodiment. [Figure 11] 11A and 11B are diagrams illustrating an example of the operation of the second embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of the operation of the second embodiment. [Figure 13] 13A and 13B are diagrams illustrating an example of the operation of the second embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of the operation of the second embodiment. [Figure 15] 15(A) and 15(B) are diagrams illustrating an example of the operation of the third embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of the operation of the embodiment 3-1. [Figure 17] FIG. 17 is a diagram illustrating an example of the operation of the fourth embodiment. [Figure 18] FIG. 18 is a diagram illustrating an example of the operation of the fifth embodiment. [Figure 19] FIG. 19 is a diagram illustrating an example of the operation of the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0015] (Configuration of a mobile communication system) First, a configuration example of a mobile communication system according to an embodiment will be described. The mobile communication system according to an embodiment is a 3GPP 5G system, but LTE (Long Term Evolution) may be applied at least partially to the mobile communication system.

[0016] FIG. 1 is a diagram showing an example of the configuration of a mobile communication system 10 according to an embodiment.

[0017] As shown in FIG. 1, a mobile communication system 10 includes a user equipment (UE) 100 and a 5G radio access network (NG-RAN) 300.

[0018] The UE 100 is a mobile device. The UE 100 may be any device that is used by a user, but for example, the UE 100 is a device capable of wireless communication, such as a mobile phone terminal (including a smartphone), a tablet terminal, a notebook PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), an aircraft or a device provided in an aircraft (Aerial UE), etc. In addition, the UE 100 in this embodiment can directly perform wireless communication with other UEs by using side link communication.

[0019] The NG-RAN 300 includes a base station device 200-1, which is called a "gNB" ("next generation Node B") in a 5G system. The NG-RAN 300 also includes a base station device 200-2, which is an LTE base station capable of cooperating with NR (New Radio). The base station device 200-2 is called an "ng-eNB."

[0020] The gNB200-1 and the ng-eNB200-2 are sometimes called NG-RAN nodes. The gNB200-1 and the ng-eNB200-2 are connected to each other via an Xn interface, which is an interface between base stations. The gNB200-1 and the ng-eNB200-2 manage one or more cells. The gNB200-1 and the ng-eNB200-2 perform wireless communication with the UE100 that has established a connection with their own cells. The gNB200-1 and the ng-eNB200-2 have a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, and the like. The term "cell" is used as a term indicating the smallest unit of a wireless communication area. The term "cell" is also used as a term indicating a function or resource for wireless communication with the UE100. One cell belongs to one carrier frequency.

[0021] As shown in Fig. 1, the gNB 200-1 and the ng-eNB 200-2 are connected via an Xn interface. The gNB 200-1 and the ng-eNB 200-2 and the UE 100-2 are connected via a Uu interface, which is a base station-user equipment interface. The UEs 100-1 to 100-3 are connected via a PC5 interface, which is a user equipment interface.

[0022] In addition, 3GPP specifies NR sidelink communication and V2X sidelink communication. The NR sidelink communication is, for example, communication that enables at least V2X communication between the UEs 100-1 to 100-3 using NR (New Radio) technology without passing through a network node. The V2X sidelink communication is, for example, communication that enables V2X communication using E-UTRA (Evolved - Universal Terrestrial Radio Access) technology without passing through a network node. Hereinafter, the NR sidelink communication and the V2X sidelink communication may be referred to as "sidelink communication" without being particularly distinguished from each other. Therefore, the "sidelink communication" may include NR sidelink communication and V2X sidelink communication.

[0023] 1, the gNB 200-1 may be connected to a 5G Core network (5GC), which is a 5G core network, and the ng-eNB 200-2 may be connected to an Evolved Packet Core (EPC), which is an LTE core network. Alternatively, the gNB 200-1 may be connected to an EPC, and the ng-eNB 200-2 may be connected to a 5GC.

[0024] In the following, the gNB 200-1 will be described as an example of a base station device, representatively between the gNB 200-1 and the ng-eNB 200-2. Also, the gNB 200-1 may be referred to as the gNB 200, and the UEs 100-1 to 100-3 may be referred to as the UEs 100.

[0025] FIG. 2 is a diagram showing a configuration of a UE 100 (user equipment) according to an embodiment.

[0026] As shown in FIG. 2, the UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit .

[0027] The receiving unit 110 performs various receptions under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts (down-converts) a radio signal received by the antenna into a baseband signal (received signal) and outputs the signal to the control unit 130. Note that the UE 100 in this embodiment is capable of performing wireless communication by side link communication not only with the gNB 200 but also with other UEs. Therefore, the receiving unit 110 is also capable of receiving messages or data transmitted from other UEs.

[0028] The transmission unit 120 performs various transmissions under the control of the control unit 130. The transmission unit 120 includes an antenna and a transmitter. The transmitter converts (up-converts) a baseband signal (transmission signal) output by the control unit 130 into a radio signal and transmits the signal from the antenna. In this embodiment, the transmission unit 120 is capable of transmitting data and the like to the gNB 200 as well as transmitting messages or data and the like to other UEs by sidelink communication.

[0029] The control unit 130 performs various controls in the UE 100. The control unit 130 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of a baseband signal. The CPU executes programs stored in the memory to perform various processes. The control unit 130 in this embodiment is capable of performing various controls or processes described in the following examples.

[0030] FIG. 3 is a diagram showing the configuration of a gNB 200 (base station) according to one embodiment.

[0031] As shown in FIG. 3, the gNB 200 includes a transmitter 210, a receiver 220, a control unit 230, and a backhaul communication unit 240.

[0032] The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts (up-converts) a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna.

[0033] The receiving unit 220 performs various receptions under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts (down-converts) a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

[0034] The control unit 230 performs various controls in the gNB 200. The control unit 230 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs executed by the processor and information used in the processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processing. Instead of the CPU, a processor or controller such as a DSP (Digital Signal Processor) or an FPGA (Field Programmable Gate Array) may be used.

[0035] The backhaul communication unit 240 is connected to adjacent base stations via an inter-base station interface. The backhaul communication unit 240 is connected to each node of the 5GC via an inter-base station-core network interface. Note that the gNB 200 is composed of a CU (Central Unit) and a DU (Distributed Unit) (i.e., the functions are divided), and both units may be connected by an F1 interface.

[0036] (About the protocol stack in the Uu interface) FIG. 4 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data in the Uu interface.

[0037] As shown in FIG. 4, the user plane radio interface protocol in the Uu interface includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0038] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the gNB 200 via a physical channel.

[0039] The MAC layer performs data priority control, retransmission processing using Hybrid Automatic Repeat Request (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE100 and the MAC layer of gNB200 via a transport channel. The MAC layer of gNB200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be assigned to UE100.

[0040] The RLC layer transmits data to the RLC layer on the receiving side by using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via a logical channel.

[0041] The PDCP layer performs header compression / decompression and encryption / decryption.

[0042] The SDAP layer maps IP flows, which are units for QoS (Quality of Service) control by the core network, to radio bearers, which are units for QoS control by the AS (Access Stratum). Note that if the RAN is connected to the EPC, the SDAP is not necessary.

[0043] 5 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals) in the Uu interface. In addition, in FIG. 5, AMF (Access and Mobility Management Function) is shown as a node included in 5GC.

[0044] As shown in FIG. 5, the protocol stack of the radio interface of the control plane in the Uu interface has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer instead of the SDAP layer shown in FIG.

[0045] Between the RRC layer of the UE 100 and the RRC layer of the gNB 200, RRC signaling for various settings is transmitted. The RRC layer controls logical channels, transport channels, and physical channels in response to establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC idle state. Also, when the RRC connection is interrupted (suspended), the UE 100 is in an RRC inactive state.

[0046] The NAS layer, which is located above the RRC layer, performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the AMF 300.

[0047] In addition, the UE 100 has an application layer and the like in addition to the protocol of the radio interface.

[0048] (Protocol stack for PC5 interface) FIG. 6 is a diagram illustrating an example of the configuration of a user plane protocol stack in a PC5 interface.

[0049] As shown in FIG. 6, the user plane protocol in the PC5 interface includes a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer, similar to the user plane protocol in the Uu interface.

[0050] FIG. 7 is a diagram showing an example of the configuration of a protocol stack of the control plane in the PC5 interface.

[0051] As shown in FIG. 7, the control plane protocol in the PC5 interface also includes a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an RRC layer, similar to the control plane protocol in the Uu interface.

[0052] In the MAC layer of the user plane, data is transmitted via the transport layer in the sidelink communication (Sidelink Control Channel (SCCH), Sidelink Transport Channel (STCH), and Sidelink Broadcast Control Channel (SBCCH)). In the MAC layer of the control plane, control information is transmitted via the transport layer in the sidelink communication. Furthermore, in the MAC layer of at least one of the planes, priority handling between uplink communication and sidelink communication, reporting of sidelink CSI (Channel State Information), etc. are performed.

[0053] Furthermore, in the RRC layer of the control plane, the transfer of PC5-RRC messages between the peer UEs 100-1 and 100-2, the maintenance and management of the PC5-RRC connection, the detection of failure of the sidelink radio link in the PC5-RRC connection, and the like are performed.

[0054] The PC5-RRC connection is a logical connection between two UEs 100 for a pair of source and destination IDs in layer 2. The PC5-RRRC connection is established after the corresponding PC5 unicast link is established. There is a one-to-one relationship between the PC5-RRC connection and the PC5 unicast link. The UE 100 can have multiple PC5-RRC connections with one or more other UEs having different source and destination ID pairs in layer 2. The UE 100 releases the PC5-RRC connection when it is not interested in sidelink communication or when the layer 2 link release procedure is completed. The PC5-RRC-connected UEs 100-1 and 100-2 are in a PC5-RRC connected (connected) state.

[0055] (Physical channel for sidelink communication) Physical channels in sidelink communication include a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink feedback channel (PSFCH), and a physical sidelink broadcast channel (PSBCH).

[0056] In the PSCCH, control information related to resources used by the UE 100 for the PSSCH and the like are transmitted. In the PSCCH, different control information (SCI: Sidelink Control Information) may be transmitted in two stages. In the PSSCH, a part of control information such as transmission of a TB (Transport Block) of data and a HARQ procedure is transmitted. In the PSFCH, HARQ feedback information is transmitted from the UE 100-2, which is the reception target of the PSSCH transmission, to the UE 100-1, which performed the transmission. The PSFCH may be applied to unicast transmission and groupcast transmission. In the PSBCH, a direct frame number (DFN), information related to synchronization, and the like are transmitted.

[0057] (Example of operation) Next, an operation example will be described. The operation example will be described in the following order.

[0058] (Example 1) Sidelink DRX (Discontinuous Reception) is not applied during RRC reconfiguration sidelink sequence

[0059] (Example 2) The sidelink DRX period boundary is reset at the time of transmission or reception of an RRC reconfiguration sidelink message or an RRC reconfiguration complete sidelink message.

[0060] (Example 3) UE 100 transmits an RRC reconfiguration sidelink message including both its own sidelink DRX configuration and the other party's sidelink DRX configuration.

[0061] (Example 3-1) In Example 3, multiple sidelink DRX configurations are notified

[0062] (Example 3-2) UE 100 notifies only the sidelink DRX configuration of the other party in the RRC reconfiguration sidelink message and the RRC reconfiguration complete sidelink message.

[0063] (Example 3-3) UE 100 notifies only its own sidelink DRX configuration in the RRC reconfiguration sidelink message and the RRC reconfiguration complete sidelink message.

[0064] (Example 4) UE 100 transmits a sidelink DRX adjustment request message to a counterpart UE

[0065] (Example 5) UE 100 requests gNB 200 to change sidelink DRX setting

[0066] (Example 6) The gNB 200 performs sidelink DRX configuration when configuring sidelink resources

[0067] Example 1 In 3GPP, discontinuous reception (DRX) in sidelink communication is about to be started. Discontinuous reception in sidelink communication is sometimes called "sidelink DRX."

[0068] Specifically, for example, issues under consideration include defining on-duration and off-duration in sidelink DRX, identifying a mechanism for aligning sidelink DRX wake-up times between UEs 100, and identifying a mechanism for aligning sidelink DRX wake-up times and UuDRX wake-up times within a coverage range.

[0069] In sidelink DRX, as in DRX between UE 100 and gNB 200, a reduction in power consumption of UE 100 is expected.

[0070] On the other hand, Fig. 8A is a diagram illustrating an example in which sidelink communication is about to be performed between the UEs 100-1 and 100-2. In the example of Fig. 8A, the UE 100-1 is a transmitting side, and the UE 100-2 is a receiving side.

[0071] 8B is a diagram illustrating an example of a sequence of sidelink RRC reconfiguration. By executing such a sequence of sidelink RRC reconfiguration between the UEs 100-1 and 100-2, sidelink communication is enabled.

[0072] In step S101, the UE 100-1 transmits an RRC reconfiguration sidelink message to the UE 100-2. The RRC reconfiguration sidelink message is a message for transmitting configuration information of the PC5 connection between the UEs 100-1 and 100-2 (or including configuration information related to sidelink communication), such as establishing, changing, or releasing a sidelink DRB (Data Radio Bearer), or configuring NR (New Radio) sidelink measurements and reports. Alternatively, the RRC reconfiguration sidelink message is also a command for an AS (Access Stratum) of the PC5-RRC connection, for example.

[0073] In step S102, the UE 100-2 transmits an RRC reconfiguration complete sidelink message. This process is performed, for example, when the UE 100-2 accepts the configuration information included in the RRC reconfiguration sidelink message received in step S101. The RRC reconfiguration complete sidelink message is, for example, a message used to confirm that the PC5-RRC AS reconfiguration has been successfully completed (or related to the completion of the configuration of sidelink communication).

[0074] By such a side link reconfiguration sequence, a PC5-RRC connection is established between UE 100-1 and 100-2, enabling data transmission and reception, etc., between UE 100-1 and 100-2.

[0075] In addition, when the UE 100-2 does not accept the configuration information included in the RRC reconfiguration sidelink message received in step S101, it is also possible to transmit an RRC Reconfiguration Failure Sidelink message. The RRC reconfiguration failure sidelink message is, for example, a message used to indicate failure of PC5-RRC AS reconfiguration (or configuration).

[0076] FIG. 9(A) is a diagram showing an example of On-duration (hereinafter, may be referred to as "Onduration") and Off-duration (hereinafter, may be referred to as "Offduration") in sidelink DRX. For example, in the Onduration period, UE 100 transmits and receives messages or transmits and receives data. On the other hand, in the Offduration period, UE 100 stops (or suspends) the transmission and reception of messages or data, for example. Therefore, in UE 100, it is possible to reduce power consumption compared to a case where sidelink DRX is not performed. A period consisting of On-duration and Off-duration (that is, for example, a period between the start point of a certain On-duration and the start point of the next On-duration) may be referred to as a DRX cycle.

[0077] FIG. 9(B) is a diagram showing an example of a relationship between each period of sidelink DRX and a message. As shown in FIG. 9(B), the UE 100-1 transmits an RRC reconfiguration sidelink message in Onduration. However, an RRC reconfiguration complete sidelink message may be transmitted from the UE 100-2 in Offduration. In this case, the UE 100-1 cannot receive the RRC reconfiguration complete sidelink message. Therefore, there are cases where a PC5-RRC connection cannot be established between the UE 100-1 and the UE 100-2.

[0078] Therefore, in the first embodiment, sidelink DRX is not applied during the sidelink RRC reconfiguration sequence. That is, in the first embodiment, waiting for a sidelink RRC reconfiguration complete message is given priority over sidelink DRX.

[0079] That is, when UE 100-1 transmits an RRC message including setting information regarding sidelink communication, if discontinuous reception is set between UE 100-2, UE 100-1 performs a standby process for receiving a response message to the RRC message regardless of the setting of discontinuous reception. Then, UE 100-1 receives the response message transmitted from UE 100-2. As a result, even if discontinuous reception is set in sidelink communication, UE 100-1 receives the response message to set sidelink communication, and is connected to UE 100-2 via PC5-RRC, enabling sidelink communication.

[0080] Fig. 10(A) is a diagram showing an example in which standby is prioritized. As shown in Fig. 10(A), after transmitting an RRC reconfiguration sidelink message, UE 100-1 prioritizes standby over sidelink DRX. UE 100-1 performs standby processing until receiving an RRC reconfiguration sidelink complete message. Then, when UE 100-1 receives the RRC reconfiguration sidelink complete message, it resumes sidelink DRX.

[0081] FIG. 10B is a diagram illustrating an example of the operation of the UE 100-1.

[0082] In step S100, the UE 100-1 starts the process.

[0083] In step S105, if sidelink DRX is configured when transmitting the RRC reconfiguration sidelink message, the UE 100-1 performs a reception waiting process regardless of the sidelink DRX configuration. Instead of the waiting process, the UE 100-1 may extend the onduration period of the sidelink DRX. Alternatively, the UE 100-1 may suspend (interrupt) the offduration period. Alternatively, the UE 100-1 may stop the onduration timer until the UE 100-1 receives the RRC reconfiguration complete sidelink message. Alternatively, the UE 100-1 may exclude or remove the application of the sidelink DRX configuration. Alternatively, the UE 100-1 may discard the sidelink DRX configuration.

[0084] In step S106, when the UE 100-1 receives the RRC reconfiguration sidelink complete message, the UE 100-1 performs an operation according to the sidelink DRX configuration. Alternatively, the UE 100-1 may return to the original sidelink DRX operation. That is, the UE 100-1 performs a standby operation according to the sidelink DRX. Alternatively, the UE 100-1 may stop the extension process of the Onduration period. Also, the UE 100-1 may resume the Offduration period that has been suspended. Alternatively, the UE 100-1 may resume (or reset) the Onduration timer that has been stopped. Alternatively, the UE 100-1 may apply (or reapply) the sidelink DRX configuration.

[0085] Then, in step S107, the UE 100-1 ends the series of processes.

[0086] In this manner, in the first embodiment, when the UE 100 transmits the RRC reconfiguration sidelink message, if the sidelink DRX is set, the UE 100 prioritizes the reception waiting process over the sidelink DRX. Therefore, even if the UE 100 is applied with the sidelink DRX, the UE 100 can execute a series of sequences of the sidelink RRC reconfiguration, and the PC5-RRC connection can be established between the UEs 100-1 and 100-2.

[0087] Example 2 In sidelink DRX, onduration and offduration are performed at the same timing between UE 100-1 and 100-2. Therefore, how to align the timing between UE 100-1 and 100-2 is an issue. Specifically, how to align the wake-up timing (i.e., the transmission timing of UE 100-1 and the discontinuous reception timing according to sidelink DRX in UE 100-2) between UE 100-1 and 100-2 and perform sidelink DRX operation by onduration and offduration is an issue.

[0088] Therefore, in this embodiment 2, the sidelink DRX periodic boundary is reset at the time of transmission or reception of an RRC reconfiguration sidelink message, or at the time of transmission or reception of an RRC reconfiguration complete sidelink message.

[0089] That is, the frame number of the predetermined frame is reset at the timing when the UE 100-1 transmits an RRC message including setting information related to the sidelink communication, or at the timing when the UE 100-2 receives the RRC message transmitted from the UE 100-1. Alternatively, the frame number of the predetermined frame is reset at the timing when the UE 100-2 transmits an RRC message related to the completion of the setting of the sidelink communication, or at the timing when the UE 100-1 receives the RRC message related to the completion of the setting transmitted from the UE 100-2.

[0090] This allows the number of a predetermined frame to be set to "0" at the same timing between UE 100-1 and 100-2, and enables timing alignment based on this timing.

[0091] The predetermined frame may be a side link DRX frame (hereinafter, may be referred to as a "DRX frame").

[0092] Fig. 11(A) is a diagram showing an example in which the DRX frame is reset at the initial transmission timing among the transmission times of the RRC reconfiguration sidelink message. Here, the "initial transmission" refers to the first transmission (step S101-1) when the RRC reconfiguration sidelink message is retransmitted (steps S101-1, S101-2, ...) as shown in Fig. 11(A). In this way, since the RRC reconfiguration sidelink message may be transmitted multiple times, the transmission time of the initial transmission of the message is set as the reset point in the example of Fig. 11(A).

[0093] In this case, the UE 100-1 notifies the receiving UE 100-2 of the transmission timing of the initially transmitted RRC reconfiguration sidelink message, so that the receiving UE 100-2 can know the transmission timing. The transmission timing may be included in the RRC reconfiguration sidelink message of step S101-1 and transmitted. Alternatively, the transmission timing may be transmitted in a separate message.

[0094] As a result, the transmitting UE 100-1 and the receiving UE 100-2 can both grasp the transmission timing of the initial transmission of the RRC reconfiguration sidelink message. Then, the UEs 100-1 and 100-2 set this transmission timing as the zero point of the DRX frame. The zero point of the DRX frame becomes the same timing between the UEs 100-1 and 100-2, and it becomes possible to align the timing of wake-up and the like based on this.

[0095] FIG. 11(B) shows an example in which the first reception timing of an RRC reconfiguration sidelink message is set as the zero point of the DRX frame among the reception times of the RRC reconfiguration sidelink message.

[0096] In the example of Figure 11 (B), when an RRC reconfiguration sidelink message is retransmitted (step S101-1, step S101-2, ...), the reception timing of the initially transmitted RRC reconfiguration sidelink message (step S101-1) is set to the zero point timing of the DRX frame.

[0097] The reception timing of the initially-transmitted RRC reconfiguration sidelink message may be included in a negative acknowledgement (NACK) message for the initially-transmitted RRC reconfiguration sidelink message. The negative acknowledgement message is, for example, a message transmitted to the transmitting UE 100-1 when the UE 100-2 fails to receive the initially-transmitted RRC reconfiguration sidelink message normally. This makes it possible to notify the transmitting UE 100-1 of the reception timing. The reception timing may be notified by being included in a message other than the negative acknowledgement message.

[0098] Then, the initial reception timing of the RRC reconfiguration sidelink message can be shared between the transmitting UE 100-1 and the receiving UE 100-2. Then, the UEs 100-1 and 100-2 can perform timing alignment by setting this timing as the zero point of the DRX frame.

[0099] Fig. 12 shows an example in which the timing at which the RRC reconfiguration sidelink message is successfully received (or successfully retransmitted) among the reception times of the RRC reconfiguration sidelink message is set as the zero point of the DRX frame. In the example of Fig. 12, in the transmission of the second RRC reconfiguration sidelink message (step S101-2), an acknowledgement (ACK) message is transmitted from the UE 100-2 (step S103). Therefore, the reception timing of the second RRC reconfiguration sidelink message (step S101-2) is the timing at which the RRC reconfiguration sidelink message is successfully received.

[0100] The reception timing may be transmitted, for example, in an acknowledgement message (step S103) or another message. This allows the UEs 100-1 and 100-2 to share the timing at which the RRC reconfiguration sidelink message was successfully received. Then, the UEs 100-1 and 100-2 set this timing as the zero point of the DRX frame, so that the DRX frames become "0" at the same timing, enabling timing alignment.

[0101] FIG. 13(A) shows an example in which the reception time of the RRC reconfiguration complete sidelink message is set as the zero point of the DRX frame.

[0102] That is, the example of Figure 13 (A) represents a case where UE 100-2 transmits an RRC reconfiguration completion side message in response to an RRC reconfiguration sidelink message (step S101), but UE 100-1 is unable to receive the message successfully and retransmits the message (steps S102-1, S102-2, ...).

[0103] Figure 13 (A) shows an example in which the timing of the transmission of the first RRC reconfiguration complete sidelink message (step S102-1) among the RRC reconfiguration complete sidelink messages retransmitted in this manner is set to the zero point of the DRX frame.

[0104] Again, this transmission timing may be transmitted to the UE 100-1, for example, by an RRC reconfiguration complete sidelink message or another message.

[0105] By setting the transmission timing of the first RRC reconfiguration complete sidelink message for UE 100-1 and UE 100-2 to the zero point of the DRX frame, the DRX frame becomes "0" at the same timing, making it possible to align the timing between UE 100-1 and UE 100-2.

[0106] Fig. 13(B) is an example in which the reception time of the RRC reconfiguration complete sidelink message is set as the zero point of the DRX frame. That is, the example in Fig. 13(B) is an example in which the RRC reconfiguration sidelink message (step S101) is transmitted, and then the reception timing of the first transmitted RRC reconfiguration complete sidelink message (step S102-1) is set as the zero point of the DRX frame.

[0107] In this case, the UE 100-1 may include the reception timing of the initially transmitted RRC reconfiguration complete sidelink message in a negative acknowledgement message for the initially transmitted RRC reconfiguration complete sidelink message or in another message, and transmit the same to the UE 100-2.

[0108] Fig. 14 shows an example in which the timing of successful reception of the RRC reconfiguration complete sidelink message, i.e., the timing of successful retransmission of the RRC reconfiguration complete sidelink message, is set as the zero point of the DRX frame. Note that the various zero points described above, including Fig. 14, may be the transmission or reception timing of an acknowledgement message (ACK).

[0109] The example of Figure 14 is an example in which UE 100-1 transmits an RRC reconfiguration sidelink message (step S101) and successfully receives the second RRC reconfiguration complete sidelink message (step S102-2), and the reception timing of this message is set to the zero point of the DRX frame.

[0110] This reception timing may be included in, for example, the acknowledgement message (step S104) or another message and transmitted to the UE 100-2.

[0111] 13B and 14, UE 100-1 and 100-2 can set the DRX frame to the zero point at the same timing based on the reception timing, which makes it possible to perform timing alignment between UE 100-1 and 100-2.

[0112] 11(A) to 14, the case where the DRX frame is set to "0" has been described. In the UEs 100-1 and 100-2, it is possible to perform side link DRX using the DRX frames set to "0" at the same timing.

[0113] Here, the frame number of the DRX frame will be described. The DRX frame number and the DRX subframe number may be calculated by the following formulas.

[0114] [DRX frame number] = ([Current SFN (System Frame Number)] - [SFN at zero point]) mod 1024 ··· (1)

[0115] [DRX subframe number] = ([current SFN] - [SFN at zero point]) mod 10 (2)

[0116] These formulas may be stored in, for example, a memory in control unit 130. In UE 100-1, 100-2, when calculating the DRX frame number, by storing the acquired SFN at the zero point in a memory or the like, it is possible to calculate the DRX frame or the DRX subframe using formula (1) or formula (2).

[0117] In the above example including formula (1) or (2), DFN (Direct Frame Number) may be used instead of SFN. Alternatively, in the above example including formula (1) or (2), a time frame derived from a reference time (e.g., GPS (Global Positioning System) time, etc.) may be used instead of SFN. Here, the time unit (frame number unit) of the time frame should be 10 ms unit.

[0118] For example, even if UE 100-1 uses SFN and UE 100-2 uses DFN and the frame numbers are different between UE 100-1 and 100-2, timing synchronization can be achieved between UE 100-1 and 100-2 by using the DRX frame. Also, even if UE 100-1 and UE 100-2 are located in different cells and are asynchronous with each other, timing synchronization can be achieved between UE 100-1 and 100-2 by using the DRX frame.

[0119] However, the DRX frame is managed for each PC5-RRC connection. That is, other PC5-RRC connections operate with other DRX frames. For example, the DRX frame between UE 100-1 and UE 100-2 and the DRX frame between UE 100-2 and UE 100-3 may have different DRX frame numbers at a certain timing.

[0120] UE 100 can obtain the same effect as the timing adjustment by conventional offset value setting by adjusting the transmission timing of a PC5-RRC message such as an RRC reconfiguration sidelink message or an RRC reconfiguration complete sidelink message.

[0121] Example 3 In the third embodiment, an RRC reconfiguration sidelink message is transmitted including both its own sidelink DRX configuration and the other party's sidelink DRX configuration.

[0122] That is, the UE 100-1 transmits an RRC message including first setting information on the setting of the discontinuous reception in the sidelink communication of the UE 100-1 and second setting information on the setting of the discontinuous reception in the sidelink communication of the UE 100-2. The UE 100-2 receives this RRC message. This enables the UEs 100-1 and 100-2 to share the sidelink DRX setting and apply the setting.

[0123] The DRX configuration in the Uu interface is performed using an RRC Reconfiguration message. Meanwhile, the sidelink DRX configuration may be performed using an RRC Reconfiguration Sidelink message. The following describes how the sidelink DRX configuration (hereinafter, sometimes referred to as "DRX configuration") is performed.

[0124] 15A and 15B are diagrams illustrating an example of the operation of the embodiment 3. The UE 100-1 is a transmitting side, and the UE 100-2 is a receiving side.

[0125] In step S110, the UE 100-1 transmits an RRC reconfiguration sidelink message including configuration information of its own (transmitter) DRX setting and configuration information of the other party's (receiver) DRX setting. Here, the own DRX setting is the DRX setting of the UE 100-1 itself. The other party's DRX setting is, for example, the DRX setting of the other party (receiver) UE 100-2 desired by the UE 100-1 (transmitter). The DRX setting may include, for example, a period related to onduration and offduration, a QoS (Quality of Service) latency, and the like. The UE 100-1 transmits its own DRX setting and the other party's DRX setting desired by the UE 100-1 to the other party's UE 100-2. Such information is included in the RRC reconfiguration sidelink message as configuration information and transmitted.

[0126] In step S111, the counterpart UE 100-2 determines whether or not the received DRX setting of the transmitting side and the DRX setting of the receiving side are acceptable, and if acceptable, transmits an RRC reconfiguration complete sidelink message to the UE 100-1 in step S112.

[0127] Thereafter, the UEs 100-1 and 100-2 apply the sidelink DRX configuration accepted by the UE 1002, and become able to transmit and receive data during the Onduration period.

[0128] On the other hand, as shown in FIG. 15(B), in step S115, UE 100-2 determines whether the received transmitting side DRX setting and receiving side DRX setting are acceptable or not, and if UE 100-2 is not acceptable (or does not want to accept), in step 116, it transmits an RRC reconfiguration failure sidelink message to UE 100-1.

[0129] In step 116, the UE 100-2 may transmit an RRC reconfiguration complete sidelink message including a counterproposal instead of an RRC reconfiguration failure sidelink message. The counterproposal may be, for example, a sidelink DRX configuration desired by the receiving UE 100-2. An example of the counterproposal may be a reception timing desired by the UE 100-2.

[0130] For example, the UE 100-2 may transmit an RRC reconfiguration failure sidelink message, but in this case, the transmitting UE 100-1 may perform other processing, such as reporting a failure of the attempted sidelink DRX or the like to the gNB 200. Thus, by the UE 100-2 transmitting an RRC reconfiguration completion sidelink message including a counterproposal, such processing is not performed, and it is also possible to improve the efficiency of the processing.

[0131] The transmitting UE 100-1 that has received the RRC reconfiguration complete sidelink message including the counterproposal may terminate the procedure if the counterproposal is acceptable. Alternatively, the transmitting UE 100-1 may transmit the RRC reconfiguration sidelink message including the counterproposal setting again to the receiving UE 100-2.

[0132] On the other hand, if the transmitting UE 100-1 that has received the RRC reconfiguration completion sidelink message including the counterproposal cannot accept the counterproposal, the transmitting UE 100-1 may again transmit an RRC reconfiguration sidelink message including a second counterproposal to the UE 100-2.

[0133] (Example 3-1) In this embodiment 3-1, an RRC reconfiguration sidelink message is transmitted including multiple DRX settings of the terminal itself and multiple DRX settings of the other terminals.

[0134] For example, when a plurality of DRX configurations of the own and a plurality of DRX configurations of the other party are notified, if an RRC reconfiguration sidelink message including the DRX configurations of the own and the other party is transmitted multiple times, the number of times of message transmission increases accordingly, and therefore the negotiation may take a long time.

[0135] Therefore, in this embodiment 3-1, by notifying a plurality of DRX settings from each of the own device and the other device, it becomes possible to perform DRX setting in less time than in the case of notifying a plurality of times.

[0136] FIG. 16 is a diagram illustrating an example of the operation of this embodiment 3-1.

[0137] In step S120, the transmitting UE 100-1 transmits an RRC reconfiguration sidelink message including a plurality of DRX settings for itself (the transmitting side) and a plurality of DRX settings for the other party (the receiving side) to the receiving UE 100-2.

[0138] In this case, the UE 100-1 may include a plurality of its own configurations and a plurality of peer configurations as candidate lists in the RRC reconfiguration sidelink message. The UE 100-1 may also notify the priority of the candidates in the sense of notifying its own preference. In this case, an identifier indicating the priority may be included in each entry (each DRX configuration) of the candidate list. Alternatively, the UE 100-1 may notify the entries of the candidate list sorted by priority.

[0139] In step S121, the UE 100-2 identifies an acceptable DRX setting from among a plurality of DRX settings of the transmitting side and a plurality of DRX settings of the receiving side. In this case, the UE 100-2 may select a DRX setting that matches a DRX setting set with another UE that is connected with the PC5-RRC connection.

[0140] In step S122, the UE 100-2 transmits an RRC reconfiguration complete sidelink message including the specified DRX configuration to the UE 100-1. In this case, the UE 100-2 may transmit the RRC reconfiguration complete sidelink message including the accepted DRX configuration itself. Alternatively, the UE 100-2 may transmit the RRC reconfiguration complete sidelink message including the entry number or configuration number of the candidate list.

[0141] In addition, when the UE 100-2 cannot accept all (candidate list of) DRX configurations included in the RRC reconfiguration sidelink message (or does not like all of them), the UE 100-2 may transmit an RRC reconfiguration failure sidelink message to the UE 100-1. In this case, the UE 100-2 may transmit the RRC reconfiguration failure sidelink message including cause information that the DRX configuration is not accepted.

[0142] (Example 3-2) As a modification of the above-described embodiment 3-1, the UE 100 may transmit an RRC reconfiguration sidelink message and an RRC reconfiguration complete sidelink message including the DRX configuration of only the other party (receiving side).

[0143] In this case, for example, in step S120 in FIG. 16, the transmitting UE 100-1 transmits an RRC reconfiguration sidelink message that includes the DRX setting of the other party (receiving side) and does not include its own (transmitting side) DRX setting.

[0144] In step S121, the receiving side UE 100-2 identifies an acceptable DRX setting from among the DRX settings of the other party (the receiving side).

[0145] In step S122, the receiving side UE 100-2 transmits an RRC reconfiguration complete sidelink message including the DRX configuration of the identified counterpart (receiving side) to the UE 100-1.

[0146] Also in the embodiment 3-2, the UE 100-1 may transmit only the DRX configurations of a plurality of counterparts (receiving sides) in step S120.

[0147] (Example 3-3) As a modification of the above-described embodiment 3-2, the UE 100 may transmit an RRC reconfiguration sidelink message and an RRC reconfiguration complete sidelink message including a DRX configuration of only itself (the transmitting side).

[0148] In this case, for example, in step S120 in FIG. 16, the UE 100-1 on the transmitting side transmits an RRC reconfiguration sidelink message that includes its own (transmitting side) DRX setting and does not include the DRX setting of the other party (receiving side).

[0149] In step S121, the receiving UE 100-2 identifies an acceptable DRX setting from its own (transmitting side) DRX settings.

[0150] In step S122, the receiving side UE 100-2 transmits an RRC reconfiguration complete sidelink message including the identified DRX configuration of its own (transmitting side) to the UE 100-1.

[0151] Also in the embodiment 3-3, the UE 100-1 may transmit only a plurality of DRX configurations of itself (the transmitting side) in step S120.

[0152] In this embodiment 3-3, the UE 100-1 on the transmitting side notifies the UE 100-2 on the receiving side of its own DRX reception setting among its own (transmitting side) DRX settings.

[0153] Example 4 The fourth embodiment is an example in which, when adjustment of the sidelink DRX is necessary, the UE 100 transmits a sidelink DRX adjustment request message (hereinafter, may be referred to as an "adjustment request message") to a counterpart UE.

[0154] That is, the UE 100-1 transmits an RRC message including setting information related to discontinuous reception in the side link communication, and the UE 100-2 receives the RRC message. Then, the UE 100-2 transmits, to the UE 100-1, an adjustment request message requesting adjustment of the setting of the discontinuous reception in the side link communication.

[0155] In the fourth embodiment, for example, the operation is performed based on the following concept. That is, the sidelink DRX configuration by the RRC reconfiguration sidelink message has no right to reject. The UE 100 that has received the sidelink DRX configuration accepts this configuration for the time being. Then, if the UE 100 is dissatisfied, it adjusts the sidelink DRX configuration by an adjustment request message.

[0156] The UE 100 that has received the sidelink DRX configuration by the RRC reconfiguration sidelink message can accept the configuration to reduce the latency of starting data communication. On the other hand, if the UE 100 is dissatisfied with the configuration, the UE 100 can raise an objection by using an adjustment request message. The adjustment request message may be a message for the UE 100 to request an adjustment of the sidelink DRX configuration.

[0157] FIG. 17 is a diagram illustrating an example of the operation of the fourth embodiment.

[0158] In step S130, the UE 100-1 on the transmitting side transmits an RRC reconfiguration sidelink message including configuration information for sidelink DRX configuration to the UE 100-2 on the receiving side.

[0159] In step S131, the receiving UE 100-2 accepts the DRX configuration and transmits an RRC reconfiguration complete sidelink message to the transmitting UE 100-1.

[0160] In steps S132 and S133, the UE 100-1 on the transmitting side and the UE 100-2 on the receiving side apply the DRX setting.

[0161] In step S134, the UE 100-1 on the transmitting side transmits data to the UE 100-2 on the receiving side during the period Onduration.

[0162] In step S135, when the UE 100-2 of the receiving side needs to adjust the DRX setting, the UE 100-2 of the transmitting side transmits an adjustment request message to the UE 100-1 of the transmitting side. The adjustment request message may include a plurality of candidate settings (preferences) regarding the DRX setting, as in the embodiment 3-1. The adjustment request message may be an RRC reconfiguration sidelink message or a new message, for example, a sidelink DRX reconfiguration request (SidelinkDRXReconfigurationRequest) message.

[0163] In step S136, the transmitting UE 100-1 reviews the DRX setting in consideration of the adjustment request message, and resets the side link DRX.

[0164] In step S137, the transmitting UE 100-1 transmits an RRC reconfiguration sidelink message including configuration information of the reconfigured DRX configuration to the receiving UE 100-2. In this case, the message transmitted by the transmitting UE 100-1 may be a new message for changing only the DRX configuration, for example, a Sidelink DRX Reconfiguration message, instead of the RRC reconfiguration sidelink message.

[0165] In the above example, the UE 100-2 on the receiving side transmits the adjustment request message. For example, the UE 100-1 on the transmitting side may transmit the adjustment request message. In this case, the UE 100-2 on the receiving side that has received the adjustment request message may perform sidelink reconfiguration and transmit an RRC reconfiguration sidelink message including configuration information of the reconfigured sidelink DRX configuration to the UE 100-1 on the transmitting side.

[0166] Example 5 Example 5 is an example in which UE 100 notifies gNB 200 of assistant information or requests a sidelink DRX setting change.

[0167] That is, the UE 100-1 transmits an RRC message including setting information related to discontinuous reception in the sidelink communication, and the UE 100-2 receives the RRC message. Then, the UE 100-2 transmits a sidelink information message requesting a change in the setting of the discontinuous reception in the sidelink communication to the gNB 200.

[0168] In the fourth embodiment, the UE 100 transmits an adjustment request message to the counterpart UE, whereby the counterpart UE adjusts the sidelink DRX. In the fifth embodiment, the UE 100 transmits a sidelink information message to the gNB 200, requesting a change in the sidelink DRX setting, whereby the gNB 200 adjusts the sidelink DRX. The gNB 200 can change the sidelink DRX setting as well as the setting change of the DRX between the gNB 200 and the UE 100 (hereinafter, sometimes referred to as "UuDRX"), and can improve the efficiency of processing. The concept described in the fourth embodiment may also be applied to the fifth embodiment.

[0169] FIG. 18 is a diagram illustrating an example of the operation of the fifth embodiment.

[0170] Steps S130 to S134 are the same as those in the fourth embodiment.

[0171] In step S140, the receiving side UE 100-2 transmits a Sidelink UE Information message including DRX setting information to the gNB 200.

[0172] The DRX setting information may be a desired setting value of UuDRX. The DRX setting information may include at least a DRX cycle and an offset as a desired setting value, and may optionally include an Onduration timer value.

[0173] The DRX setting information may also be a setting value of the sidelink DRX. The setting value of the sidelink DRX may be a setting value currently being applied (steps S132 and S133). The DRX setting information may include at least a DRX cycle and an offset as a setting value, and may optionally include an Onduration timer value. The setting value may also be a plurality of sidelink DRX setting values. The plurality of sidelink DRX setting values ​​may or may not be associated with each destination. Furthermore, the setting value may be a value converted into DFN or SFN when the DRX frame described in the second embodiment is used.

[0174] Furthermore, the DRX setting information may be a setting value of the sidelink DRX desired for the counterpart UE 100 (UE 100-1 in the example of FIG. 18). This setting value itself may be the same as the setting value of the sidelink DRX described above.

[0175] In step S141, the gNB 200 performs reconfiguration in consideration of the DRX setting information included in the sidelink UE information message. As the reconfiguration, the gNB 200 may reconfigure the UuDRX setting of the UE 100-2. Alternatively, as the reconfiguration, the gNB 200 may reconfigure the sidelink DRX setting of the UE 100-2. Alternatively, as the reconfiguration, the gNB 200 may reconfigure the sidelink DRX setting of the other party (the UE 100-1 in the example of FIG. 18).

[0176] In addition, the gNB 200 may transmit the reset sidelink DRX configuration to the UE 100-1 or UE 100-2 (or both the UE 100-1 and 100-2) by using a PDSCH (Physical Downlink Shared CHannel) or by broadcast information, for example. In addition, the gNB 200 may transmit the reset UuDRX configuration to the UE 100-2 by using the PDSCH or broadcast information.

[0177] In the above example, the receiving UE 100-2 notifies the gNB 200 of the DRX setting information. The transmitting UE 100-1 may transmit a sidelink UE information message including the DRX setting information to the gNB 200. In this case, the receiving UE 100-2 may be set as the other UE, and the same implementation as the above example is possible.

[0178] Example 6 In the above-described embodiments, the sidelink DRX configuration is mainly performed between the UEs 100. In this embodiment, the gNB 200 also performs the sidelink DRX configuration when configuring resources used in the sidelink communication.

[0179] That is, the gNB 200 transmits an RRC message including setting information related to the setting of discontinuous reception in sidelink communication or broadcasts system information including the setting information. Then, the UEs 100-1 and 100-2 receive the RRC message and apply the setting of discontinuous reception in sidelink communication.

[0180] FIG. 19 is a diagram illustrating an example of the operation of the sixth embodiment.

[0181] In step S150, the gNB 200 performs sidelink DRX configuration for the UEs 100 (in the example of FIG. 19, UEs 100-1 and UEs 100-2).

[0182] In steps S151 and S152, the gNB 200 transmits an RRC reconfiguration message including the configuration information of the configured sidelink DRX configuration to the UE 100-1 and the UE 100-2. The configuration information may be notified using a SIB (System Information Block) instead of the RRC reconfiguration message. The configuration information may include all or part of the DRX configuration information described in the fifth embodiment. When part of the DRX configuration information is included, for example, only the DRX cycle and the Onduration timer may be included as the part of the DRX configuration information, and the other DRX configuration information (for example, off time, etc.) may be determined by the UE 100. A hybrid operation is performed in which part of the sidelink DRX configuration is configured by the gNB 200 and the other part is configured by the UE 100. Alternatively, the configuration information may be performed (or linked) for each resource pool.

[0183] In steps S153 and S154, the transmitting UE 100-1 and the receiving UE 100-2 apply the sidelink DRX configuration notified from the gNB 200.

[0184] In this case, the transmitting UE 100-1 may transmit an RRC reconfiguration sidelink message including a sidelink DRX configuration to the receiving UE 100-2, taking into consideration the sidelink DRX configuration notified from the gNB 200. For example, the UE 100-1 may notify the sidelink DRX configuration including the sidelink DRX configuration including the offset determined by the UE 100-1 and the other sidelink DRX configurations set by the gNB 200, in the RRC reconfiguration sidelink message. In this case, the UE 100-1 may notify the sidelink DRX configuration determined by the UE 100-1 itself by including it in the RRC reconfiguration sidelink message, in anticipation of the other sidelink DRX configurations being transmitted from the gNB 200 to the UE 100-2.

[0185] (Other embodiments) A program may be provided that causes a computer to execute each process performed by the UE 100 or the gNB 200. The program may be recorded in a computer-readable medium. Using the computer-readable medium, it is possible to install the program in the computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

[0186] In addition, circuits that execute each process performed by UE100 or gNB200 may be integrated, and at least a part of UE100 or gNB200 may be configured as a semiconductor integrated circuit (chip set, SoC).

[0187] Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like are possible without departing from the scope of the invention. In addition, it is also possible to combine all or part of each embodiment as long as there is no contradiction.

[0188] This application claims priority to Japanese Patent Application No. 2020-169444 (filed October 6, 2020), the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0189] 10: Mobile communication systems 100(100-1~100-3):UE 110: Receiving unit 120: Transmitter 130: Control section 200(200-1):gNB 200-2:ng-eNB 210: Transmission unit 220: Receiving unit 230: Control section 240: Backhaul communication unit

Claims

1. A communication control method, comprising: A user equipment receives setting information regarding a setting of discontinuous reception in side link communication with another user equipment from the other user equipment; When the user device accepts the setting according to the setting information, the user device performs discontinuous reception according to the setting information; and transmitting the accepted configuration information to a base station by the user equipment. Communications control method.

2. A user device, A communication unit that receives setting information regarding a setting of discontinuous reception in side link communication with another user device from the other user device, When the communication unit accepts the setting information, the communication unit performs intermittent reception according to the setting information; The communication unit transmits the accepted setting information to a base station. User equipment.

3. A processor for controlling a user device, A process of receiving setting information regarding a setting of discontinuous reception in side link communication with another user device from the other user device; A process of performing discontinuous reception according to the setting information when the setting according to the setting information is accepted; and transmitting the accepted setting information to a base station. Processor.

4. A communication system including a user device, another user device that performs sidelink communication with the user device, and a base station, The user equipment receives setting information regarding a setting of discontinuous reception in sidelink communication with the other user equipment from the other user equipment, When the user device accepts the setting according to the setting information, the user device performs discontinuous reception according to the setting information; The user equipment transmits the accepted configuration information to a base station. Communication systems.

5. A program for controlling a user device, A process of receiving setting information regarding a setting of discontinuous reception in side link communication with another user device from the other user device; A process of performing discontinuous reception according to the setting information when the setting according to the setting information is accepted; and causing the user equipment to execute a process of transmitting the accepted setting information to a base station. program.

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