Communication device, control method, and program

Abstract

This provides technology for properly performing relay communication. [Solution] A communication device according to one aspect of the present disclosure is a communication device that operates as a relay device in a UE (User Equipment)-to-UE Relay, which generates mobility information relating to the movement of the communication device and transmits the mobility information toward the End UE.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a control method, and a program.

Background Art

[0002] In the 3rd Generation Partnership Project (3GPP (registered trademark): 3rd Generation Partnership Project), cellular communication standards (also referred to as 3GPP standards) have been established. In recent years, the specifications of LTE (Long Term Evolution) and NR (New Radio) of 3GPP have been progressing. Among these, a standard specification called sidelink communication has been established. This specification realizes direct wireless communication between wireless terminals using an interface called PC5 without going through a mobile communication network (core network).

[0003] In 3GPP, the standardization of 5G ProSe (Proximity-based services) UE-to-UE Relay is in progress. UE-to-UE Relay is a mechanism in sidelink communication where two wireless terminals (End UE) directly communicate without going through a base station, and the communication between the wireless terminals is relayed by a relay device (also described as Relay). By relaying the communication, it becomes possible to extend the communication distance between the wireless terminals. Note that UE is an abbreviation for User Equipment and may also be called a terminal device or simply a terminal.

[0004] The standard for UE-to-UE Relay is described in TS (Technical Specification) 23.304. Up to Release 18 of 3GPP, the following have been standardized. · Detection of the relay device (UE-to-UE Relay Discovery). · Establishment (also referred to as construction) of UE-to-UE Relay. · Reselection of the relay device in an established UE-to-UE Relay.

[0005] In establishing and re-selecting UE-to-UE relays, the selection of relay devices is performed by the End UE. Generally, the selection criterion is the signal strength (radio wave strength) between devices. The End UE measures the radio wave strength with multiple candidate relay devices in its vicinity and selects the candidate with the highest radio wave strength as the relay device.

[0006] Patent Document 1 describes a technique in which an End UE selects a communication path (relay device) based on path selection information that includes at least one of channel quality information, load information, and device capability information. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2023-515299 [Overview of the project] [Problems that the invention aims to solve]

[0008] Incidentally, if the relative movements (speed, direction, etc.) of the End UE and the relay device differ, there is a high probability that relay communication will be interrupted. For example, in such a case, the End UE is a moving vehicle and the relay device is a vehicle traveling in the opposite lane. Depending on the timing of the radio wave strength measurement, such as at the moment they pass each other, the radio wave strength may become high, and the selection criteria for the relay device may be met. Even if relay communication is established using a relay device selected in this way, the distance between the devices will increase relatively quickly, and communication will be interrupted.

[0009] One possible solution is for the End UE to obtain information about the movement of relay devices (referred to as mobility information) from the relay devices. For example, based on the acquired mobility information, the End UE can select a relay device whose relative movement is similar to that of the End UE, thereby establishing less interrupted communication. Similarly, a method could be considered for the relay device to obtain mobility information from the End UE. However, the method for obtaining mobility information in UE-to-UE Relay is not clearly defined. If the method for obtaining mobility information is not clearly defined, it may not be possible to use the mobility information of other devices, and relay communication may not be performed properly.

[0010] One aspect of this disclosure, in view of the above, aims to provide a technology for appropriately performing relay communication. [Means for solving the problem]

[0011] A communication device according to one aspect of this disclosure is a communication device that operates as a relay device in a UE (User Equipment)-to-UE Relay, and comprises a generating means for generating mobility information relating to the movement of the communication device, and a transmitting means for transmitting the mobility information toward the End UE. [Effects of the Invention]

[0012] According to one aspect of this disclosure, relay communication can be performed appropriately. [Brief explanation of the drawing]

[0013] [Figure 1] This block diagram shows an example of the hardware configuration of the End UE and relay device according to the embodiment. [Figure 2] This is a block diagram showing an example of the functional configuration of an End UE and relay device according to an embodiment. [Figure 3] This is a diagram showing an example configuration of a communication system according to the embodiment. [Figure 4]It is a diagram showing an example of the data format of mobility information according to an embodiment. [Figure 5] It is a sequence diagram showing an example of UE-to-UE Relay establishment processing according to the first embodiment. [Figure 6] It is a flowchart showing an example of relay device (or relay device candidate) selection processing according to the first embodiment. [Figure 7] It is a sequence diagram showing an example of UE-to-UE Relay establishment processing according to the second embodiment. [Figure 8] It is a sequence diagram showing an example of UE-to-UE Relay reselection processing according to the third embodiment. [Figure 9] It is a flowchart showing an example of UE-to-UE Relay reselection execution determination processing according to the third embodiment. [Figure 10] It is a sequence diagram showing an example of UE-to-UE Relay reselection processing according to the fourth embodiment.

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the content described in the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations may be given the same reference numerals, and duplicate explanations may be omitted. Also, the technical scope of the present disclosure is determined by the claims and is not limited by the following individual embodiments.

[0015] <First Embodiment> In this embodiment, an example of using mobility information in a sequence of establishing UE-to-UE Relay using UE-to-UE Relay Discovery will be described.

[0016] FIG. 1 is a block diagram showing an example of the hardware configuration of an End UE and a relay device according to an embodiment. In various embodiments including this embodiment, the End and the relay device can have, for example, the hardware configuration 101 shown in FIG. 1.

[0017] The hardware configuration 101 includes a control unit 102, a storage unit 103, a wireless communication unit 104, a communication antenna control unit 105, a GPS communication unit 106, and a GPS antenna control unit 107. GPS is an abbreviation for Global Positioning System.

[0018] The control unit 102 is composed of, for example, one or more processors such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). The control unit 102 controls the entire device by executing, for example, a control program (a control program read into a RAM (Random Access Memory)) stored in the storage unit 103. Each process performed by the control unit 102 described later using the flowchart can also be realized using a hardware circuit such as an ASIC or an FPGA. ASIC is an abbreviation for Application Specific Integrated Circuit, and FPGA is an abbreviation for Field Programmable Gate Array. Also, by the cooperation of the hardware circuit and processors such as the CPU and MPU, the processes described later using the flowchart can be realized.

[0019] The memory unit 103 stores control programs executed by the control unit 102, as well as various types of information such as cell information, connected terminal information, and mobility information. The memory unit 103 may include a main memory unit and an auxiliary memory unit. The main memory unit is, for example, ROM (Read Only Memory), RAM, etc. The main memory unit may store or temporarily store programs and data such as the OS (Operating System), application software, etc., which are the basic software executed by the control unit 102. The auxiliary memory unit is, for example, an HDD (Hard Disk Drive), SSD (Solid State Drive), etc. The auxiliary memory unit may store data related to application software, etc. For example, a control program stored in a non-volatile memory area is loaded into RAM and executed by the processor constituting the control unit 102. In this way, the control unit 102 and the memory unit 103 may function as a so-called computer.

[0020] The wireless communication unit 104 performs cellular communication such as LTE (Long Term Evolution) and 5G (NR) in accordance with 3GPP standards. In various embodiments, including this embodiment, 5G will be described, but this disclosure is also applicable to other technologies (for example, next-generation mobile communication systems such as 5G Advanced and 6G, LTE, LTE-Advanced, and combinations thereof).

[0021] The communication antenna control unit 105 controls the antenna used for wireless communication performed by the wireless communication unit 104.

[0022] The GPS communication unit 106 receives satellite signals from GPS satellites and acquires current location information, including position identification information such as latitude and longitude, and current time information. The GPS communication unit 106 may also have a function to measure (position) the current location based on satellite signals. Other GNSS (Global Navigation Satellite System) may be used instead of or in addition to GPS.

[0023] The GPS antenna control unit 107 controls the antenna used for GPS communication performed by the GPS communication unit 106.

[0024] Figure 2 is a block diagram showing an example of the functional configuration of an End UE and relay device according to an embodiment. Functions other than the data storage unit shown in Figure 2 may be implemented by software of the End UE and relay device that executes communication control functions. In various embodiments, including this embodiment, the End UE and relay device may each have, for example, software function 200 and software function 201 shown in Figure 2.

[0025] Figure 2(a) is a block diagram showing an example of the functional configuration of an End UE according to an embodiment. The software function 200 includes a signal transmission unit 202, a signal reception unit 203, a data storage unit 204, a connection control unit 205, a mobility information generation unit 206, a connection strength evaluation unit 207, a relay device selection unit 208, a relay device candidate selection unit 209, and a re-selection execution decision unit 210.

[0026] The signal transmitting unit 202 and the signal receiving unit 203 perform cellular communication such as LTE and 5G in accordance with 3GPP standards with other communication devices. Messages containing mobility information, which will be described later, are transmitted and received by the signal transmitting unit 202 and the signal receiving unit 203. The signal transmitting unit 202 is an example of a transmitting means, the signal receiving unit 203 is an example of a receiving means, and the signal transmitting unit 202 and the signal receiving unit 203 are examples of a communication means or a transmission / reception means.

[0027] The data storage unit 204 stores and retains the software itself, information about the connected terminal, mobility information, and so on. Mobility information will be described later.

[0028] The connection control unit 205 controls side link connections, relay connections, etc., with other communication devices.

[0029] The mobility information generation unit 206 generates mobility information to be notified to surrounding communication devices. For example, the mobility information generation unit 206 generates mobility information for the End UE based on location information, acceleration information, etc., acquired or calculated by the GPS communication unit 106, or by inertial sensors, acceleration sensors (not shown), etc., built into the End UE. Alternatively, for example, the mobility information generation unit 206 generates mobility information for the End UE based on user input. The mobility information generation unit 206 is just one example of a generation means.

[0030] The connection strength evaluation unit 207 evaluates the connection strength between the surrounding communication devices and the device itself based on mobility information received from surrounding communication devices and the mobility information of the device itself. In various embodiments, including this embodiment, the connection strength evaluation unit 207 evaluates the connection strength based on the similarity of the movement or physical position changes of the two communication devices. The method for evaluating the connection strength will be described later. Note that "evaluate the connection strength" may be read as "determine the connection strength". The connection strength evaluation unit 207 is an example of a determination means or an evaluation means.

[0031] The relay device selection unit 208 selects a relay device based on the connection strength evaluated based on mobility information. In various embodiments, including this embodiment, the relay device selection unit 208 selects the communication device with the highest connection strength as the relay device. The relay device selection unit 208 is an example of a selection means.

[0032] The relay device candidate selection unit 209 selects a relay device candidate based on the connection strength evaluated based on mobility information. In various embodiments, including this embodiment, the relay device candidate selection unit 209 selects a communication device whose connection strength is equal to or greater than a threshold as a relay device candidate. The relay device candidate selection unit 209 is an example of a selection means.

[0033] The re-selection decision unit 210 determines whether or not to perform re-selection of the relay device. In this embodiment, the re-selection decision unit 210 periodically checks the connection strength between its own device and the relay device. If the connection strength exceeds a threshold, it decides not to perform re-selection. If the connection strength falls below the threshold, it decides to perform re-selection. The re-selection decision unit 210 is an example of a decision means.

[0034] Figure 2(b) is a block diagram showing an example of the functional configuration of a relay device according to an embodiment. The software function 201 includes a signal transmission unit 202, a signal reception unit 203, a data storage unit 204, a connection control unit 205, a mobility information generation unit 206, a connection strength evaluation unit 207, and a message relay determination unit 211.

[0035] The signal transmitting unit 202 and the signal receiving unit 203 perform cellular communication such as LTE and 5G in accordance with 3GPP standards with other communication devices. Messages containing mobility information, which will be described later, are transmitted and received by the signal transmitting unit 202 and the signal receiving unit 203. The signal transmitting unit 202 is an example of a transmitting means, the signal receiving unit 203 is an example of a receiving means, and the signal transmitting unit 202 and the signal receiving unit 203 are examples of a communication means or a transmission / reception means.

[0036] The data storage unit 204 stores and retains the software itself, information about the connected terminal, mobility information, and so on. Mobility information will be described later.

[0037] The connection control unit 205 controls side link connections, relay connections, etc., with other communication devices.

[0038] The mobility information generation unit 206 generates mobility information to be notified to surrounding communication devices. For example, the mobility information generation unit 206 generates mobility information for the relay device based on location information, acceleration information, etc., acquired or calculated by the GPS communication unit 106, or by inertial sensors, acceleration sensors (not shown), etc., built into the relay device. Alternatively, for example, the mobility information generation unit 206 generates mobility information for the relay device based on user input. The mobility information generation unit 206 is an example of a generation means.

[0039] The connection strength evaluation unit 207 evaluates the connection strength between the surrounding communication devices and the device itself based on mobility information received from surrounding communication devices and the mobility information of the device itself. In various embodiments, including this embodiment, the connection strength evaluation unit 207 evaluates the connection strength based on the similarity of the movement or physical position changes of the two communication devices. The method for evaluating the connection strength will be described later. The connection strength evaluation unit 207 is an example of a determination means or evaluation means.

[0040] The message relay decision unit 211 decides whether or not to relay a message based on the connection strength evaluated based on mobility information. In various embodiments, including this embodiment, the message relay decision unit 211 decides to relay the message if the connection strength is above a threshold, and decides not to relay the message if the connection strength is below the threshold. The message relay decision unit 211 makes a decision on whether or not to relay a message when the signal receiving unit 203 receives a message containing a relay instruction (triggered by the signal receiving unit 203 receiving a message containing a relay instruction). Here, the relay instruction is the Relay_Indication described later. The message relay decision unit 211 is an example of a decision means.

[0041] Figure 3 shows an example of the configuration of a communication system according to the embodiment.

[0042] Figure 3(a) shows an example of a communication system configuration when the connection strength is high. End UE301 and End UE302 establish a UE-to-UE relay via relay device 303. These communication devices are moving in the same direction at the same speed. Therefore, there is a high probability that the relay connection will continue for a long period of time. In this case, the connection strength of the UE-to-UE relay is evaluated as high.

[0043] Figure 3(b) shows an example of a communication system configuration when the connection strength is low. End UE301 and End UE302 establish a UE-to-UE relay via relay device 304. In this relay, End UE301 and End UE302 are moving to the right in the diagram, while relay device 304 is moving to the opposite side (to the left in the diagram). Therefore, there is a high possibility that the relay connection will be interrupted. In this case, the connection strength of the UE-to-UE relay is evaluated as low.

[0044] Next, we will explain the mobility information used when evaluating connection strength.

[0045] Figure 4 shows an example of a data format for mobility information according to the embodiment.

[0046] MobilityInfo400, which represents the overall mobility information, is appended to several messages used in communication between the End UE and the relay device, as described later.

[0047] MobilityInfo400 includes Device identification information401, Mobility-StatusInfo402, and Mobility-Profile405.

[0048] Device identification information 401 is the identification information of the communication device. Since a message may contain mobility information for multiple communication devices, Device identification information 401 is used to identify which communication device the mobility information belongs to. For example, a User Info ID may be used as the identification information for the communication device.

[0049] Mobility-StatusInfo402 is simplified mobility information. When there are limitations on the amount of data that can be attached to a message, the data size can be reduced by attaching only simplified mobility information. Mobility-StatusInfo402 includes Mobility-StatusIndication403, which indicates the movement status of the communication device (whether the communication device is moving or stationary). Mobility-StatusInfo402 also includes GuaranteedStaticTime404, which indicates the downtime of the communication device.

[0050] Mobility-Profile405 contains detailed mobility information. Adding detailed mobility information to the message increases the data size, but allows for a more accurate assessment of connection strength.

[0051] Mobility-Profile405 includes Speed-Info406, which provides information about the communication device's speed, and Mobility-Area-Info407, which provides information about the communication device's area of ​​operation. The information about the communication device's speed may include, for example, at least one of the maximum speed, minimum speed, and average speed over a given period. The information about the communication device's area of ​​operation may include, for example, information identifying the cell in which the communication device is located (e.g., cell ID, base station name, etc.). Mobility-Profile405 also includes StaticDuration-Info408, which provides detailed information about the downtime, such as the elapsed downtime and the scheduled downtime (scheduled start time and scheduled end time). Mobility-Profile405 also includes Geolocation-Info409, which provides information about the communication device's physical location (e.g., latitude and longitude) and direction of movement.

[0052] Next, we will describe the processing flow for establishing a UE-to-UE Relay based on mobility information.

[0053] Figure 5 is a sequence diagram showing an example of the UE-to-UE Relay establishment process according to the first embodiment. The sequence shown in Figure 5 is equivalent to the sequence of the UE-to-UE Relay establishment process described in Section 6.7.1 of TS23.304.

[0054] In this embodiment, the mobility information of the relay device is notified to the End UE by adding the mobility information of the relay device to the Discovery message used in the existing sequence. In addition, in this embodiment, the process by which the End UE selects a relay device is modified so that the relay device is selected based on mobility information rather than radio wave strength.

[0055] First, Source End UE301, Target End UE302, and Relay303 perform service authentication and provisioning (S501).

[0056] Next, Source End UE301 performs 5G ProSe UE-to-UE Relay Discovery (S502). There are two types of 5G ProSe UE-to-UE Relay Discovery: Model A and Model B. 5G ProSe UE-to-UE Relay Discovery is defined in Section 6.3.2.4 of TS23.304.

[0057] Model A is implemented by a relay device notifying surrounding communication devices of an announcement message (UE-to-UE Relay Discovery Announcement message) (see Section 6.3.2.4.2 of TS23.304). In this embodiment, the relay device (Relay303) adds its own mobility information to the announcement message and notifies surrounding communication devices of this announcement message. The End UEs (Source End UE301 and Target End UE302) obtain the mobility information of the relay device from the received announcement message. According to TS23.304 and TS24.554, the UE-to-UE Relay Discovery Announcement message is a type of 5G ProSe direct discovery message.

[0058] Model B is implemented through the following two notifications (see Section 6.3.2.4.3 of TS23.304): (1) Notification of a discovery request message (UE-to-UE Relay Discovery Solicitation message) from the Source End UE to the Target End UE. According to TS23.304 and TS24.554, the UE-to-UE Relay Discovery Solicitation message is a type of 5G ProSe direct discovery message. (2) Notification of a discovery response message (UE-to-UE Relay Discovery Response message) from the Target End UE to the Source End UE after receiving a discovery request message. According to TS23.304 and TS24.554, a UE-to-UE Relay Discovery Response message is a type of 5G ProSe direct discovery message.

[0059] In the case of UE-to-UE Relay, the detection request message and detection response message are transmitted via surrounding relay devices.

[0060] In this embodiment, when the relay device (Relay303) forwards a detection request message, it adds its own mobility information to the detection request message and notifies the End UE (Target End UE302) of the detection request message. Also in this embodiment, when the relay device (Relay303) forwards a detection response message, it adds its own mobility information to the detection response message and notifies the End UE (Source End UE301) of the detection response message. The End UE obtains the mobility information of the relay device from the received detection response message.

[0061] In the case of Model B, the End UEs (Source End UE301 and Target End UE302) may also add their own mobility information to the message. In this case, the destination End UE can know the mobility information of the source End UE and the mobility information of the relay device. The destination End UE can then comprehensively evaluate the connection strength from the mobility information of the entire UE-to-UE Relay, including its own mobility information. In addition, the relay device can also evaluate the connection strength from the mobility information of the source End UE and its own mobility information. The relay device may decide (or determine) whether or not to relay the message based on the connection strength.

[0062] Next, the Source End UE301 selects a relay device based on the connection strength evaluated based on the received mobility information (S503). Details of the process flow for the End UE to select a relay device will be described later.

[0063] The subsequent processing follows the existing sequence, so I will briefly explain it.

[0064] Source End UE301 notifies Relay303 of a Direct Communication Request message (S504) in order to establish a unicast Layer 2 link with Relay303.

[0065] Relay303 and Source End UE301 establish security (S505).

[0066] After security is established, Relay303 notifies Target End UE302 of a Direct Communication Request (S506) to establish a unicast Layer 2 link with Target End UE302.

[0067] Target End UE302 and Relay303 establish security (S507).

[0068] After security is established, the Target End UE302 notifies the Relay303 of the Direct Communication Accept message (S508).

[0069] For IP traffic, Relay303 assigns an IP (Internet Protocol) v4 address or IPv6 prefix to Target End UE302 (S509).

[0070] Relay303 notifies Source End UE301 of the Direct Communication Accept message (S510).

[0071] For IP traffic, Relay303 assigns an IPv4 address or IPv6 prefix to Source End UE301 (S511).

[0072] In the case of IP traffic, Relay303 functions as a DNS server. Therefore, upon request from Source End UE301, Relay303 notifies Source End UE301 of the IPv4 address or IPv6 prefix of Target End UE302 (S512).

[0073] Finally, Source End UE301 communicates with Target End UE302 via Relay303 (S513).

[0074] Next, we will describe the processing flow in which the End UE selects a relay device based on mobility information.

[0075] Figure 6 is a flowchart showing an example of the relay device (or relay device candidate) selection process according to the first embodiment. In the processing flow shown in Figure 6, the End UE selects a relay device (or relay device candidate) from the received mobility information. In this embodiment, the mobility information is used by the Source End UE 301 to select a relay device in S503 of Figure 5. The selection of relay device candidates will be described later in the third embodiment.

[0076] First, the Source End UE301 receives a message from a nearby communication device (S601). Then, the Source End UE301 obtains mobility information from the received message (S602).

[0077] Next, the Source End UE301 evaluates the connection strength based on the acquired mobility information (S603). Details of the connection strength evaluation will be described later.

[0078] Next, Source End UE301 determines whether the evaluated connection strength is above a threshold (S604).

[0079] If the connection strength is not above the threshold (No in S604), Source End UE301 terminates processing.

[0080] On the other hand, if the connection strength is above the threshold (Yes in S604), the Source End UE301 selects the device (the device that sent the message) as the relay device (S605). Then, the Source End UE301 terminates processing.

[0081] In this embodiment, the threshold value is the maximum value of the most recently evaluated connection strength. In other words, the communication device with the highest connection strength in the most recent instance is selected as the relay device.

[0082] Next, we will describe an example of a method for evaluating connection strength based on mobility information.

[0083] One example of a method for evaluating connection strength is to use relative speed. When the relative speed is low, the distance between devices can be kept constant for a relatively long time, making communication less likely to be interrupted. In this case, the connection strength between devices is judged to be high. Conversely, when the relative speed is high, the distance between devices widens relatively quickly, increasing the likelihood of connection interruption, so the connection strength between devices is judged to be low.

[0084] To calculate the relative speed, the information indicating the moving speed included in Speed-Info406 in MobilityInfo400 and the information indicating the moving direction included in Geolocation-Info409 in MobilityInfo400 are used. As the moving speed, any one of the maximum speed, the minimum speed, and the average speed may be used. The communication device may periodically observe the latitude and longitude information included in Geolocation-Info409 in GeolocationMobilityInfo400 to obtain the moving speed and the moving direction. The communication device calculates a relative speed vector from the speed vector of the source communication device calculated from the obtained moving speed and moving direction and the speed vector obtained based on the generated own mobility information. Then, the communication device evaluates the connection strength in N (N is an integer of 2 or more) levels based on the comparison between the magnitude (V) of the calculated relative speed vector and one or more threshold values. For example, when evaluating the connection strength in two levels (high or low), one threshold value (T) is set. In this case, for example, the communication device may evaluate the connection strength as "2" (high) if V≤T, and "1" (low) if T<V. Also, in this case, regarding the selection of relay device candidates in the third embodiment described later, for example, the threshold value compared with the connection strength in S604 is set to an arbitrary value such as "2". Also, for example, when evaluating the connection strength in four levels, three threshold values (T1<T2<T3) are set. In this case, for example, the communication device may evaluate the connection strength as "4" (high) if V≤T1, "3" (somewhat high) if T1<V≤T2, "2" (somewhat low) if T2<V≤T3, and "1" (low) if T3<V. Also, in this case, regarding the selection of relay device candidates in the third embodiment described later, for example, the threshold value compared with the connection strength in S604 is set to an arbitrary value such as "3" or "4". Alternatively, the communication device may evaluate the reciprocal of the magnitude (V) of the calculated relative speed vector as the connection strength.

[0085] As another example of the method for evaluating the connection strength, the following method can be considered.

[0086] For example, a communication device may determine that the connection strength between devices is high if the mobility area information included in the notified Mobility-Area-Info407 is the same as the mobility area information in its own generated mobility information. In this case, the communication device may evaluate the connection strength as "2". On the other hand, if this is not the case, the communication device may determine that the connection strength between devices is low (for example, it may evaluate the connection strength as "1").

[0087] Furthermore, if the latitude and longitude information included in the notified Geolocation-Info409 is close to the latitude and longitude information in its own generated mobility information, the communication device may determine that the connection strength between devices is high. In this case, the communication device may evaluate the connection strength as "2," for example. On the other hand, if this is not the case, the communication device may determine that the connection strength between devices is low (for example, it may evaluate the connection strength as "1"). Here, "close" may mean that the distance between communication devices calculated from this latitude and longitude information is less than or equal to a predetermined value.

[0088] Furthermore, if the period during which the stop scale included in StaticDuration-Info408 matches the stop scale in its generated mobility information is long, the communication device may determine that the connection strength between devices is high. In this case, the communication device may evaluate the connection strength as "2," for example. On the other hand, if this is not the case, the communication device may determine that the connection strength between devices is low (for example, it may evaluate the connection strength as "1"). Here, the stop scale refers to the period from the scheduled stop start time to the scheduled stop end time, and "long" may mean that the period during which these stop scales match is greater than or equal to a predetermined value.

[0089] Alternatively, the communication device may simply determine that the connection strength between devices is high if the movement status (moving or stopped) included in Mobility-StatusIndication403 matches the movement status in its generated mobility information. In this case, the communication device may evaluate the connection strength as "2," for example. On the other hand, if this is not the case, the communication device may determine that the connection strength between devices is low (for example, it may evaluate the connection strength as "1").

[0090] Furthermore, the communication device may evaluate the connection strength using any combination of the above methods (for example, by taking the average or weighted average of the above connection strength values).

[0091] Furthermore, the communication device may evaluate the connection strength by considering both mobility information and radio wave strength.

[0092] Which information in the mobility information is used for connection strength evaluation (which evaluation method is used) may be determined by the base station, the End UE, or the relay device.

[0093] In this way, communication devices can establish relay communication that is less prone to interruptions by selecting devices with high connection strength (in other words, devices with similar relative movements) as relay devices based on mobility information.

[0094] According to this embodiment, the relay device adds its mobility information to announcement messages or detection request messages and detection response messages, and notifies the End UE of these messages. The End UE evaluates the connection strength based on the notified mobility information (and its own mobility information) and selects a relay device based on the connection strength. As a result, a relay device with a high connection strength is selected based on the mobility information, which reduces or prevents communication interruptions in relay communication and ensures communication stability. Therefore, relay communication can be performed appropriately.

[0095] <Second Embodiment> In the first embodiment, an example of using mobility information in a sequence for establishing a UE-to-UE Relay using UE-to-UE Relay Discovery was described. In this embodiment, an example of using mobility information in a sequence for establishing a UE-to-UE Relay using integrated Discovery is described. Note that in the second embodiment, the same configuration and processing as in the first embodiment will not be described.

[0096] Figure 7 is a sequence diagram showing an example of the UE-to-UE Relay establishment process according to the second embodiment. The sequence shown in Figure 7 is equivalent to the sequence of the UE-to-UE Relay establishment process described in Section 6.7.3 of TS23.304. As described above, the process shown in Figure 7 uses integrated discovery.

[0097] In this embodiment, the mobility information of the relay device is notified to the End UE by adding the mobility information of the relay device to the Direct Communication Request message used in the existing sequence. In addition, in this embodiment, the process by which the End UE selects a relay device is modified so that the relay device is selected based on mobility information rather than signal strength. According to TS23.304 and TS24.554, the Direct Communication Request message can be said to be a type of 5G ProSe direct communication message.

[0098] First, the Source End UE301, Target End UE302, and relay devices (Relay-1 and Relay-2) perform service authentication and provisioning (S701).

[0099] Next, Source End UE301 broadcasts a Direct Communication Request message to Target End UE302, allowing relaying by the relay device (S702). Relaying permission is controlled by the Relay_Indication included in the Direct Communication Request message (see Section 11.3.56 of TS24.554, etc.). If the Direct Communication Request message includes Relay_Indication, relaying of the Direct Communication Request message is permitted. On the other hand, if the Direct Communication Request message does not include Relay_Indication, relaying of the Direct Communication Request message is not permitted. In this embodiment, Source End UE301 includes Relay_Indication in the Direct Communication Request message and broadcasts this message.

[0100] When the relay devices (Relay-1 and Relay-2) receive a Direct Communication Request message from the Source End UE301, they perform the following actions in S703. Specifically, the relay devices (Relay-1 and Relay-2) broadcast a Direct Communication Request message destined for the Target End UE302 without allowing relaying by the relay devices (S703). In other words, the relay devices (Relay-1 and Relay-2) broadcast the Direct Communication Request message without including Relay_Indication. In addition, in this embodiment, the relay devices (Relay-1 and Relay-2) add the mobility information of the relay devices to the Direct Communication Request message and broadcast this message.

[0101] When the Target End UE302 receives a Direct Communication Request message from one or more relay devices, it performs the following operation in S704: The Target End UE302 evaluates the connection strength based on the mobility information contained in the Direct Communication Request message and selects a relay device based on the evaluated connection strength (S704). The processing flow for selecting a relay device and the method for evaluating the connection strength are the same as in the first embodiment, so a description is omitted. Note that in S704, the selection of a relay device and the evaluation of the connection strength are performed by the Target End UE302, not the Source End UE.

[0102] Here, in S701, the Source End UE301 may also add its own mobility information to the Direct Communication Request message. In this case, the Target End UE can know the mobility information of the Source End UE and the mobility information of the relay device. The Target End UE can then comprehensively evaluate the connection strength from the mobility information of the entire UE-to-UE Relay, including its own mobility information. In addition, the relay device can also evaluate the connection strength from the mobility information of the Source End UE and its own mobility information. Based on the connection strength, the relay device may decide (or determine) whether or not to relay the Direct Communication Request message.

[0103] The subsequent processing follows the existing sequence, so we will explain it briefly. In this embodiment, we will explain using the case where Relay-1 is selected as the relay device as an example.

[0104] Relay-1 and Target End UE302 establish security (S705).

[0105] The Target End UE302 sends a Direct Communication Accept message to Relay-1 (S706).

[0106] For IP traffic, Relay-1 assigns an IPv4 address or IPv6 prefix to Target End UE302 (S707).

[0107] Source End UE301 and Relay-1 establish security (S708).

[0108] Relay-1 receives Quality of Service (QoS) information from Source End UE301. After receiving the QoS information, Relay-1 notifies Target End UE302 of the QoS information using a Link Modification Request message (S709).

[0109] When Target End UE302 receives a Link Modification Request from Relay-1, it responds to Relay-1 with a Link Modification Accept message (S710).

[0110] Relay-1 responds to Source End UE301 with a Direct Communication Accept message (S711).

[0111] For IP traffic, Relay-1 assigns an IPv4 address or IPv6 prefix to Source End UES301 (S712).

[0112] In the case of IP traffic, Relay-1 functions as a DNS server. Therefore, upon request from Source End UE301, Relay-1 notifies Source End UE301 of the IPv4 address or IPv6 prefix of Target End UE302 (S713).

[0113] Finally, Source End UE301 communicates with Target End UE302 via Relay-1 (S714).

[0114] According to this embodiment, the relay device adds its mobility information to the Direct Communication Request message and notifies the End UE of this message. The End UE evaluates the connection strength based on the notified mobility information (and its own mobility information) and selects a relay device based on the evaluated connection strength. As a result, a relay device with a high connection strength is selected based on the mobility information, which reduces or prevents communication interruptions in relay communication and ensures communication stability. Therefore, relay communication can be performed appropriately.

[0115] <Third Embodiment> In the first and second embodiments, examples of using mobility information in the sequence for establishing a UE-to-UE Relay were described. In this embodiment, an example of using mobility information in the sequence for re-selecting a relay device after establishing a UE-to-UE Relay will be described. Note that in the third embodiment, the same configurations and processes as in the first or second embodiment will not be described.

[0116] Figure 8 is a sequence diagram showing an example of the UE-to-UE Relay reselection process according to the third embodiment. The reselection of the relay device by the UE-to-UE Relay reselection process is performed after the UE-to-UE Relay is established. Figure 8 shows the process flow for changing the relay device from Relay-1 to Relay-2. The sequence shown in Figure 8 is equivalent to the sequence of the UE-to-UE Relay reselection process described in Section 6.7.4 of TS 23.304.

[0117] In this embodiment, mobility information of candidate relay devices is notified to the End UE by adding mobility information to periodically notified messages and Link Modification Request messages. In addition, in this embodiment, the process by which the End UE decides to re-select a relay device and the process of selecting a relay device are modified to be based on mobility information rather than radio wave strength. According to TS23.304 and TS24.554, a Link Modification Request message can be said to be a type of 5G ProSe direct communication message.

[0118] Source End UE301 and Target End UE302 are configured with Relay-1 and PC5 unicast links (S801).

[0119] Source End UE301 and Target End UE302 are configured with Relay-2 and PC5 unicast links (S802).

[0120] Source End UE301 and Target End UE302 are forwarding traffic via Relay-1 (S803).

[0121] The relay devices (Relay-1 and Relay-2) add the relay device's mobility information to the message they send to the Source End UE301 and then send the message to the Source End UE301 (S804). The messages sent from the relay devices to the Source End UE301 are messages that are periodically notified. Examples of periodically notified messages include announcement messages (UE-to-UE Relay Discovery Announcement message) and PC5 RRC messages (measurement report). The Source End UE301 can periodically evaluate the connection strength with the relay devices by obtaining mobility information from the periodically notified messages. The connection strength with Relay-1 can be used to decide whether to re-select a relay device, and the connection strength with Relay-2 can be used to select a candidate relay device when re-selecting a relay device.

[0122] Next, Source End UE301 decides to perform a re-selection of the relay device (S805).

[0123] The following describes the processing flow for deciding whether to re-select the relay device.

[0124] Figure 9 is a sequence diagram showing an example of the UE-to-UE Relay reselection decision process according to the third embodiment. Figure 9 shows the process flow in which the End UE decides to perform reselection of the relay device based on the mobility information it receives.

[0125] First, the Source End UE301 receives a message from the relay device (S901). Then, the Source End UE301 obtains mobility information from the received message (S902).

[0126] Next, the Source End UE301 evaluates the connection strength based on the acquired mobility information (S903). The details of the connection strength evaluation are the same as in the first embodiment, so the explanation is omitted.

[0127] Next, Source End UE301 determines whether the evaluated connection strength is below a threshold (S904).

[0128] If the connection strength is not below the threshold (No in S904), Source End UE301 returns to S901 and waits for the next message to be received.

[0129] On the other hand, if the connection strength is below the threshold (Yes in S904), the Source End UE301 decides to re-select the relay device (S905). Then, the Source End UE301 terminates the process.

[0130] Returning to the explanation of Figure 8, the Source End UE301 then selects a candidate relay device (S806). The candidate relay device is selected based on mobility information, similar to the relay device itself. The Source End UE301 may select multiple candidate relay devices. The Source End UE301 may obtain the mobility information used to select the candidate relay device from the message notified in S804, or it may obtain (receive) mobility information again from surrounding communication devices after deciding to perform a re-selection. If mobility information is obtained again, 5G ProSe UE-to-UE Relay Discovery is performed as in the first embodiment. When using Model B, if the Direct Discovery set is not set in the discovery request message, the surrounding communication device that received the message, rather than the Target End UE, will return the discovery response message. As mentioned above, the discovery request message is a UE-to-UE Relay Discovery Solicitation message. The discovery response message is a UE-to-UE Relay Discovery Response message. Surrounding communication devices can notify the End UE of their mobility information by adding their own mobility information to a detection response message and sending the detection response message.

[0131] Next, we will describe the processing flow by which End UE selects candidate relay devices based on mobility information.

[0132] The selection of relay device candidates is processed according to the processing flow shown in Figure 6, similar to the selection of relay devices described in the first embodiment. Therefore, a detailed explanation of the selection of relay device candidates is omitted. The difference from the first embodiment is that, in the selection of relay device candidates, an arbitrary value is used as the connection strength threshold in S604, as described above, and communication devices whose connection strength is equal to or greater than the threshold are selected as relay device candidates. As described above, multiple relay device candidates may be selected.

[0133] Returning to the explanation of Figure 8, the Source End UE301 then sends a Link Modification Request message to the Target End UE302 via the relay device (Relay-1) (S807, S808). This message contains a relay reselection instruction. In addition, the Source End UE301 adds mobility information of the selected relay device candidate to this message.

[0134] The Target End UE302 selects a relay device from the relay device candidates according to the relay reselection instruction included in the received Link Modification Request (S809). The relay device is selected based on mobility information according to the processing flow shown in Figure 6, similar to the first embodiment. Selecting a relay device can be considered as selecting or determining the communication path between the Source End UE301 and the Target End UE302.

[0135] In S807, the Source End UE301 may also add its own mobility information to the Link Modification Request message. In this case, the Target End UE can know the mobility information of the Source End UE and the mobility information of the candidate relay device. The Target End UE can then comprehensively evaluate the connection strength from the mobility information of the entire UE-to-UE Relay, including its own mobility information.

[0136] The subsequent processing follows the existing sequence, so I will briefly explain it.

[0137] The Target End UE302 sends a Link Modification Accept message to the Source End UE301 via the relay device (Relay-1) (S810, S811). This message contains the user information ID of the new relay device (Relay-2) selected by the Target End UE302.

[0138] Source End UE301 sends a Link Modification Ack to Target End UE302 via Relay-1 (S812, S813).

[0139] Finally, Source End UE301 communicates with Target End UE302 via the new relay device (Relay-2) (S814).

[0140] According to this embodiment, a relay device candidate adds its mobility information to a message (such as a periodically notified message) and notifies the End UE of this message. The Source End UE evaluates the connection strength based on the notified mobility information (and its own mobility information) and selects a relay device candidate based on the connection strength. The Source End UE adds the relay device candidate's mobility information to a Link Modification Request message and notifies the Target End UE of this message. The Target End UE evaluates the connection strength based on the notified mobility information (and its own mobility information) and re-selects a relay device based on the connection strength. As a result, a relay device with a high connection strength is re-selected based on the mobility information, which reduces or prevents communication interruptions in relay communication, ensures communication stability, and reduces the load associated with re-selecting a relay device. Therefore, relay communication can be performed appropriately.

[0141] <Fourth Embodiment> In the third embodiment, an example of using mobility information in a sequence for re-selecting a relay device was described. In this embodiment, an example of using mobility information in a sequence for re-selecting a relay device using integrated Discovery will be described. Furthermore, in the integrated Discovery of the second embodiment, a single-hop UE-to-UE Relay involving one relay device was described. In this embodiment, in addition to the above, a multi-hop UE-to-UE Relay involving multiple relay devices will be described. Note that in the fourth embodiment, the same configurations and processes as in the first, second, or third embodiment will not be described.

[0142] Figure 10 is a sequence diagram showing an example of the UE-to-UE Relay reselection process according to the fourth embodiment. The reselection of the relay device by the UE-to-UE Relay reselection process is performed after the UE-to-UE Relay is established. Figure 10 shows the process flow for changing the relay devices from Relay-1 and Relay-2 to Candidate Relay-1 and Candidate Relay-2, respectively. As described above, the process shown in Figure 10 uses integrated discovery.

[0143] Source End UE301 and Target End UE302 forward traffic via Relay-1 and Relay-2 (S1001).

[0144] The relay devices (Relay-1 and Relay-2) add the relay device's mobility information to the message they send to the Source End UE301 and then send the message to the Source End UE301 (S1002). The process in S1002 is the same as the process in S804 in Figure 8 of the third embodiment, so the explanation is omitted. The Source End UE301 obtains mobility information from the messages that are notified periodically.

[0145] Next, Source End UE301 decides to perform a re-selection of the relay device (S1003). The decision to perform the re-selection is carried out according to the processing flow shown in Figure 9, similar to the third embodiment. Therefore, the explanation of the decision to perform the re-selection is omitted.

[0146] When Source End UE301 decides to perform reselection, it performs the following action in S1004: Source End UE301 broadcasts a Direct Communication Request message to Target End UE302, allowing relaying by the relay device (S1004). Here, relaying permission is controlled by Relay_Indication included in the message. In this embodiment, the way Relay_Indication is used changes to support multi-hop. In single-hop, Relay_Indication is used like a flag, and message relaying is included in the message only if permitted. In contrast, in multi-hop, Relay_Indication is used as a parameter representing the number of times relaying is permitted. When establishing a multi-hop UE-to-UE Relay with two relay devices, Source End UE301 stores "2" in Relay_Indication. When a surrounding communication device receives a message containing Relay_Indication, it decrements the value of Relay_Indication by 1 before notifying the next communication device of the message. When the value of Relay_Indication is 0, relaying of that message is not permitted. In this embodiment, Source End UE301 broadcasts the Direct Communication Request message with Relay_Indication set to 2 in order to allow relaying twice.

[0147] When Candidate Relay-1 receives a Direct Communication Request message from Source End UE301, it performs the following action in S1005: Candidate Relay-1 includes a value of 1 (Relay_Indication decremented by 1) in the Direct Communication Request message and broadcasts this message to the surrounding area (S1005). In addition, in this embodiment, Candidate Relay-1 adds its mobility information to the Direct Communication Request message and broadcasts this message.

[0148] When Candidate Relay-2 receives a Direct Communication Request message from Candidate Relay-1, it performs the following action in S1006. Specifically, Candidate Relay-2 includes 0 (Relay_Indication decremented by 1) in the Direct Communication Request message and broadcasts this message to the surrounding area (S1006). In addition, in this embodiment, Candidate Relay-2 adds its mobility information to the Direct Communication Request message and broadcasts this message.

[0149] The Target End UE302 receives Direct Communication Request messages from one or more relay devices (S1006). The Target End UE302 then evaluates the connection strength based on the mobility information contained in the Direct Communication Request message and selects a relay device based on the evaluated connection strength (S1007). The processing flow for selecting a relay device and the method for evaluating the connection strength are the same as in the first embodiment, so their explanation is omitted. In this way, the Target End UE302 can select or determine a relay device, i.e., a communication path between the Source End UE301 and the Target End UE302, based on the evaluated connection strength.

[0150] Here, in S1004, the Source End UE 301 may also add its own mobility information to the Direct Communication Request message. In this case, the Target End UE can know the mobility information of the Source End UE and the mobility information of the relay device candidate. The Target End UE can then comprehensively evaluate the connection strength from the mobility information of the entire UE-to-UE Relay, including its own mobility information. In addition, the relay device candidate can also evaluate the connection strength from the mobility information of the Source End UE and its own mobility information. The (first) relay device candidate may decide (or determine) whether or not to relay the Direct Communication Request message based on the connection strength. Furthermore, in the case of multi-hop, the second and subsequent relay device candidates can also evaluate the connection strength with the previous relay device candidate from the received Direct Communication Request message. Similarly, the second and subsequent relay device candidates may decide (or determine) whether or not to relay the Direct Communication Request message based on the connection strength.

[0151] In the sequence following the selection of a relay device, processing is performed in the same manner as in a single hop. Specifically, security establishment, sending of a Direct Communication Accept message, and assignment of an IPv4 address or IPv6 prefix are repeatedly performed in each section of the selected relay device. Therefore, a detailed explanation is omitted. Information about the relay device selected by the Target End UE is included in the Direct Communication Accept message and notified to the next relay device.

[0152] According to this embodiment, a relay device candidate adds its mobility information to a Direct Communication Request message and notifies the End UE of this message. The End UE evaluates the connection strength based on the notified mobility information (and its own mobility information) and re-selects a relay device based on the connection strength. As a result, a relay device with a high connection strength is selected based on the mobility information, which reduces or prevents communication interruptions in relay communication, ensures communication stability, and reduces the load associated with re-selecting a relay device. Furthermore, in this embodiment, communication interruptions can be reduced or prevented in multi-hop relay communication, ensures communication stability, and reduces the load associated with re-selecting a relay device. Therefore, relay communication can be performed appropriately.

[0153] <Other Embodiments> This disclosure can also be implemented by supplying a program that implements one or more of the functions of each of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. Furthermore, this disclosure can also be implemented by a circuit (e.g., an ASIC or FPGA) that implements one or more functions.

[0154] This disclosure is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of this disclosure.

[0155] The names of the functional units, messages, parameters, fields, etc., described in the embodiments described above are examples and may be changed to other names.

[0156] Furthermore, some (or sometimes all) of the above-mentioned functional blocks may be replaced with other functional blocks that perform similar functions, some functional blocks may be omitted, or additional functional blocks may be added.

[0157] Furthermore, one functional block as described above may be divided into multiple functional blocks, or multiple functional blocks may be integrated into a single functional block.

[0158] The order of the processing procedures, sequences, flowcharts, etc., in the embodiments described above is not limited to the specific order presented, and may be rearranged or additional steps may be added, as long as they do not contradict each other.

[0159] The matters described in the above embodiments may be incorporated into other embodiments, insofar as they do not contradict each other.

[0160] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0161] [Note 1] A communication device that operates as a relay device in a UE (User Equipment)-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means for transmitting the mobility information toward the End UE, A communication device having the following features.

[0162] [Note 2] The communication device according to Appendix 1, wherein the mobility information includes information indicating at least one of the following: the movement state of the communication device, the movement speed of the communication device, the stop time of the communication device, the movement area of ​​the communication device, the position of the communication device, and the direction of movement of the communication device.

[0163] [Note 3] The transmission means is a communication device according to Appendix 1 or 2, which transmits the mobility information to the End UE, including it in a 5G ProSe direct discovery message.

[0164] [Note 4] The transmission means is a communication device according to any one of the appendices 1 to 3, which transmits the mobility information to the End UE in a 5G ProSe direct communication message.

[0165] [Note 5] A communication device that operates as an End UE in a UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of the relay device from the relay device, A generation means for generating second mobility information relating to the movement of the communication device, A first determination means for determining the connection strength between the communication device and the relay device based on the first mobility information and the second mobility information, A communication device having the following features.

[0166] [Note 6] The first mobility information includes first information indicating at least one of the following: the movement state of the relay device, the movement speed of the relay device, the stopping time of the relay device, the movement area of ​​the relay device, the position of the relay device, and the direction of movement of the relay device. The communication device according to Appendix 5, wherein the second mobility information includes second information indicating at least one of the following: the movement state of the communication device, the movement speed of the communication device, the stop time of the communication device, the movement area of ​​the communication device, the position of the communication device, and the direction of movement of the communication device.

[0167] [Note 7] The communication device as described in Appendix 6, wherein the determination means calculates the relative speed between the relay device and the communication device from the moving speed and direction of the relay device and the moving speed and direction of the communication device based on the first information and the second information, and determines the connection strength based on the relative speed.

[0168] [Note 8] The communication device according to Appendix 6 or 7, wherein the determination means compares the movement state of the relay device and the movement state of the communication device based on the first information and the second information to determine the connection strength.

[0169] [Note 9] The communication device according to any one of the appendices 6 to 8, wherein the determination means calculates the distance between the relay device and the communication device from the position of the relay device and the position of the communication device based on the first information and the second information, and determines the connection strength based on the distance.

[0170] [Note 10] The communication device according to any one of the appendices 6 to 9, wherein the determination means compares the mobile area of ​​the relay device and the mobile area of ​​the communication device based on the first information and the second information to determine the connection strength.

[0171] [Note 11] When establishing or re-selecting a UE-to-UE Relay, The receiving means receives the mobility information from one or more relay devices, and the determining means determines the connection strength between one or more relay devices and the communication device based on the mobility information. The communication device according to any one of appendices 5 to 10, further comprising a first selection means for selecting the relay device having the highest connection strength among the respective connection strengths as the relay device in the UE-to-UE Relay.

[0172] [Note 12] When establishing or re-selecting a UE-to-UE Relay, The receiving means receives the mobility information from one or more relay devices, and the determining means determines the connection strength between one or more relay devices and the communication device based on the mobility information. The communication device according to any one of appendices 5 to 11, further comprising a second selection means for selecting a relay device as a candidate relay device in a UE-to-UE Relay, wherein the relay device has a connection strength equal to or greater than a first threshold among the respective connection strengths.

[0173] [Note 13] The receiving means receives the first mobility information during the UE-to-UE Relay connection. The communication device according to any one of appendices 5 to 12, further comprising a second determination means for determining whether to perform UE-to-UE Relay reselection when the connection strength falls below a second threshold.

[0174] [Note 14] A communication device that operates as a relay device in a UE-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means that periodically transmits the mobility information to the End UE during a UE-to-UE Relay connection, A communication device having the following features.

[0175] [Note 15] The transmission means is a communication device as described in Appendix 14, which transmits the mobility information to the End UE, including it in a 5G ProSe direct discovery message.

[0176] [Note 16] The transmission means is a communication device as described in Appendix 14 or 15, which transmits the mobility information to the End UE, including it in a PC5 RRC message.

[0177] [Note 17] A communication device that operates as an End UE in a UE-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means for transmitting the mobility information to a relay device, A communication device having the following features.

[0178] [Note 18] A communication device that operates as a relay device in a UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of the End UE from the End UE, A generation means for generating second mobility information relating to the movement of the communication device, A first determination means for determining the connection strength between the communication device and the End UE based on the first mobility information and the second mobility information, A communication device having the following features.

[0179] [Note 19] The communication device according to Appendix 19, further comprising a second determination means for determining whether or not to relay a message based on the aforementioned connection strength.

[0180] [Note 20] The communication device according to Appendix 19, wherein the second determination means determines to relay the message if the connection strength is equal to or greater than a threshold, and determines not to relay the message if the connection strength is less than a threshold.

[0181] [Note 21] The communication device according to Appendix 19 or 20, wherein the second determination means determines whether or not to relay the message when the receiving means receives the message which includes a relay instruction.

[0182] [Note 22] The communication device according to any one of the appendices 19 to 21, further comprising a transmission means for transmitting the second mobility information in the message when the second decision means decides to relay the message.

[0183] [Note 23] A communication device that operates as an End UE in a UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of the relay device and second mobility information relating to the movement of the other End UE from the relay device and another End UE, respectively. A generation means for generating third mobility information relating to the movement of the communication device, A selection means for selecting a communication path between the communication device and the other End UE based on the first mobility information, the second mobility information and the third mobility information, A communication device having the following features.

[0184] [Note 24] A control method performed by a communication device acting as a relay device in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process of transmitting the mobility information to the End UE, A control method including

[0185] [Note 25] A control method performed by a communication device operating as an End UE in a UE-to-UE Relay, A step of receiving first mobility information relating to the movement of the relay device from the relay device, A step of generating second mobility information relating to the movement of the communication device, A step of determining the connection strength between the communication device and the relay device based on the first mobility information and the second mobility information, A control method including

[0186] [Note 26] A control method performed by a communication device acting as a relay device in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process includes periodically transmitting the aforementioned mobility information to the End UE during the UE-to-UE Relay connection, A control method including

[0187] [Note 27] A control method performed by a communication device operating as an End UE in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process of transmitting the mobility information to a relay device, A control method including

[0188] [Note 28] A control method performed by a communication device acting as a relay device in a UE-to-UE Relay, A step of receiving first mobility information regarding the movement of the End UE from the End UE, A step of generating second mobility information relating to the movement of the communication device, A step of determining the connection strength between the communication device and the End UE based on the first mobility information and the second mobility information, A control method including

[0189] [Note 29] A control method performed by a communication device operating as an End UE in a UE-to-UE Relay, A step of receiving first mobility information relating to the movement of the relay device and second mobility information relating to the movement of the other End UE from the relay device and another End UE, respectively. A step of generating third mobility information relating to the movement of the communication device, A step of selecting a communication path between the communication device and the other End UE based on the first mobility information, the second mobility information and the third mobility information, A control method including

[0190] [Note 30] A program for causing a computer to execute any of the control methods described in Appendix 24 to 29. [Explanation of Symbols]

[0191] 101 Hardware Configuration 102 Control Unit 103 Storage section 104 Wireless Communication Section 105 Communication Antenna Control Unit 106 GPS Communication Unit 107 GPS Antenna Control Unit 200 Software Features 201 Software Features 202 Signal Transmission Unit 203 Signal receiving section 204 Data Storage Unit 205 Connection Control Unit 206 Mobility Information Generation Unit 207 Connection strength evaluation section 208 Relay device selection section 209 Relay device candidate selection unit 210 Re-selection Implementation Decision Department 211 Message Relay Decision-Making Section 301 End UE 302 End UE 303 Relay device 304 Relay device

Claims

1. A communication device that operates as a relay device in a UE (User Equipment)-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means for transmitting the mobility information toward End UE, A communication device having the following features.

2. The communication device according to claim 1, wherein the mobility information includes information indicating at least one of the following: the movement state of the communication device, the movement speed of the communication device, the stop time of the communication device, the movement area of ​​the communication device, the position of the communication device, and the direction of movement of the communication device.

3. The communication device according to claim 1 or 2, wherein the transmitting means transmits the mobility information to the End UE, including it in a 5G ProSe direct discovery message.

4. The communication device according to claim 1 or 2, wherein the transmitting means transmits the mobility information to the End UE, including it in a 5G ProSe direct communication message.

5. A communication device that operates as the End UE in a UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of the relay device from the relay device, A generation means for generating second mobility information relating to the movement of the communication device, A first determination means for determining the connection strength between the communication device and the relay device based on the first mobility information and the second mobility information, A communication device having the following features.

6. The first mobility information includes first information indicating at least one of the following: the movement state of the relay device, the movement speed of the relay device, the stopping time of the relay device, the movement area of ​​the relay device, the position of the relay device, and the direction of movement of the relay device. The communication device according to claim 5, wherein the second mobility information includes second information indicating at least one of the following: the movement state of the communication device, the movement speed of the communication device, the stop time of the communication device, the movement area of ​​the communication device, the position of the communication device, and the direction of movement of the communication device.

7. The communication device according to claim 6, wherein the determination means calculates the relative speed between the relay device and the communication device from the moving speed and direction of the relay device and the moving speed and direction of the communication device based on the first information and the second information, and determines the connection strength based on the relative speed.

8. The communication device according to claim 6, wherein the determination means compares the movement state of the relay device and the movement state of the communication device based on the first information and the second information to determine the connection strength.

9. The communication device according to claim 6, wherein the determination means calculates the distance between the relay device and the communication device from the position of the relay device and the position of the communication device based on the first information and the second information, and determines the connection strength based on the distance.

10. The communication device according to claim 6, wherein the determination means compares the movement area of ​​the relay device and the movement area of ​​the communication device based on the first information and the second information to determine the connection strength.

11. When establishing or re-selecting a UE-to-UE Relay, The receiving means receives the mobility information from one or more relay devices, and the determining means determines the connection strength between one or more relay devices and the communication device based on the mobility information. The communication device according to claim 5, further comprising a first selection means for selecting the relay device having the highest connection strength among the respective connection strengths as the relay device in UE-to-UE Relay.

12. When establishing or re-selecting a UE-to-UE Relay, The receiving means receives the mobility information from one or more relay devices, and the determining means determines the connection strength between one or more relay devices and the communication device based on the mobility information. The communication device according to claim 5, further comprising a second selection means for selecting a relay device as a candidate for a UE-to-UE relay, wherein the relay device has a connection strength equal to or greater than a first threshold among the respective connection strengths.

13. The receiving means receives the first mobility information during a UE-to-UE Relay connection. The communication device according to claim 5, further comprising a second determination means for determining whether to perform UE-to-UE Relay reselection when the connection strength falls below a second threshold.

14. A communication device that operates as a relay device in UE-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means that periodically transmits the mobility information toward the End UE during a UE-to-UE relay connection, A communication device having the following features.

15. The communication device according to claim 14, wherein the transmitting means transmits the mobility information to the End UE, including it in a 5G ProSe direct discovery message.

16. The communication device according to claim 14, wherein the transmitting means transmits the mobility information to the End UE, including it in the PC5 RRC message.

17. A communication device that operates as the End UE in a UE-to-UE Relay, A generation means for generating mobility information relating to the movement of the communication device, A transmission means for transmitting the mobility information to a relay device, A communication device having the following features.

18. A communication device that operates as a relay device in UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of End UE from End UE, A generation means for generating second mobility information relating to the movement of the communication device, A first determination means for determining the connection strength between the communication device and the End UE based on the first mobility information and the second mobility information, A communication device having the following features.

19. The communication device according to claim 18, further comprising a second determination means for determining whether or not to relay a message based on the connection strength.

20. The communication device according to claim 19, wherein the second determination means determines to relay the message if the connection strength is equal to or greater than a threshold, and determines not to relay the message if the connection strength is less than a threshold.

21. The communication device according to claim 19, wherein the second determination means determines whether or not to relay the message when the receiving means receives the message which includes a relay instruction.

22. The communication device according to any one of claims 19 to 21, further comprising a transmission means for transmitting the second mobility information in the message when the second decision means decides to relay the message.

23. A communication device that operates as the End UE in a UE-to-UE Relay, Receiving means for receiving first mobility information relating to the movement of the relay device and second mobility information relating to the movement of the other End UE from the relay device and another End UE, A generation means for generating third mobility information relating to the movement of the communication device, A selection means for selecting a communication path between the communication device and the other End UE based on the first mobility information, the second mobility information and the third mobility information, A communication device having the following features.

24. A control method performed by a communication device operating as a relay device in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process of transmitting the mobility information toward End UE, A control method including

25. A control method performed by a communication device operating as the End UE in a UE-to-UE Relay, A step of receiving first mobility information relating to the movement of the relay device from the relay device, A step of generating second mobility information relating to the movement of the communication device, A step of determining the connection strength between the communication device and the relay device based on the first mobility information and the second mobility information, A control method including

26. A control method performed by a communication device operating as a relay device in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process includes periodically transmitting the mobility information to the End UE during a UE-to-UE relay connection, A control method including

27. A control method performed by a communication device operating as the End UE in a UE-to-UE Relay, A step of generating mobility information relating to the movement of the communication device, The process of transmitting the mobility information to a relay device, A control method including

28. A control method performed by a communication device operating as a relay device in a UE-to-UE Relay, A step of receiving first mobility information relating to the movement of End UE from End UE, A step of generating second mobility information relating to the movement of the communication device, A step of determining the connection strength between the communication device and the End UE based on the first mobility information and the second mobility information, A control method including

29. A control method performed by a communication device operating as the End UE in a UE-to-UE Relay, A step of receiving first mobility information relating to the movement of the relay device and second mobility information relating to the movement of the other End UE from the relay device and another End UE, respectively. A step of generating third mobility information relating to the movement of the communication device, A step of selecting a communication path between the communication device and the other End UE based on the first mobility information, the second mobility information and the third mobility information, A control method including

30. A program for causing a computer to execute the control method described in any one of claims 24 to 29.

Images