Communication device, communication method, program, and communication system

Abstract

A communication device for communicating with a communication partner terminal, the communication device comprising: a communication unit configured to transmit a precoded radio signal to the communication partner terminal and receive a precoded radio signal from the communication partner terminal, and transmit a transmission instruction for instructing transmission of a propagation path information report to the communication partner terminal; and a setting unit configured to set precoding of a radio signal to be transmitted to the communication partner terminal based on the propagation path information report received from the communication partner terminal.

Description

Technical Field

[0001] This invention relates to communication equipment, communication methods, programs, and communication systems. Background Technology

[0002] In recent years, the 3rd Generation Partnership Project (3GPP®) has been developing specifications for Long Term Evolution (LTE) and 5G New Radio (5G NR).

[0003] In addition, in radio communication, there are precoding techniques where the transmitting side generates a signal that incorporates information about the current propagation path to improve transmission efficiency.

[0004] When precoding is performed between a base station and a terminal according to the standards developed in 3GPP, the base station determines the content of instructions regarding the terminal based on the communication status with the terminal, and then sends reference signals and instructions for reporting. Furthermore, the terminal, using its configuration based on these instructions, reports propagation path information to the base station. The base station then transmits precoded data based on the propagation path information reported from the terminal.

[0005] On the other hand, within 3GPP, a standard specification called sidelink communication (hereinafter referred to as sidelink) has been developed that does not involve a base station. This specification enables direct radio communication between terminals (user equipment (UE)) using an interface called PC5 without going through a base station or core network. Patent Document 1 describes a method for returning propagation path information to a terminal that transmitted a reference signal based on a reference signal in the sidelink. Existing technical documents Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-526741 Summary of the Invention The problem the invention aims to solve

[0007] In the case of sidelink communication, since both terminals are mobile, the propagation path state is assumed to vary more significantly compared to communication between a fixed base station and terminals. Therefore, bidirectional precoding is desired between terminals for stable communication.

[0008] This invention was made in view of at least one of the aforementioned problems. One aspect of the invention relates to providing a mechanism that enables bidirectional precoding operations between terminals. Solution for solving the problem

[0009] A communication device according to one aspect of the present invention communicates with a communication counterpart terminal and includes: a communication unit for: transmitting a precoded radio signal to the communication counterpart terminal and receiving a precoded radio signal from the communication counterpart terminal, and transmitting a transmission command to the communication counterpart terminal for instructing the transmission of a propagation path information report; and a setting unit for setting a precoding of the radio signal to be transmitted to the communication counterpart terminal based on the propagation path information report received from the communication counterpart terminal. Advantages of the invention

[0010] According to the present invention, bidirectional precoding operations between terminals enable stable communication even when the communication state between terminals changes. Attached Figure Description

[0011] Figure 1 This is a diagram illustrating an example configuration of a communication system according to this embodiment. Figure 2 This is a block diagram illustrating an example of the functional configuration of a terminal according to this embodiment. Figure 3 This is a sequence diagram according to the first embodiment. Figure 4 This is a flowchart based on the first embodiment. Figure 5 This is a flowchart based on the first embodiment. Figure 6 This is a sequence diagram according to the second embodiment. Figure 7 This is a flowchart based on the second embodiment. Figure 8 This is an example message format illustrating a precoded change notification according to the second embodiment. Figure 9 This is an example message format illustrating a precoded change notification according to the second embodiment. Figure 10 This is a sequence diagram according to the third embodiment. Figure 11 This is a flowchart based on the third embodiment. Figure 12 This is a sequence diagram according to the fourth embodiment. Figure 13 This is a flowchart based on the fourth embodiment. Detailed Implementation

[0012] The embodiments will now be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features can be freely combined. Furthermore, in the drawings, the same or similar components are indicated by the same reference numerals, and overlapping descriptions are omitted.

[0013] [First Embodiment] (System Configuration) Figure 1 This is a diagram illustrating an example of the system configuration of a communication device according to this embodiment. Figure 1 The illustrated system includes terminal A 101 and terminal B 102. In Figure 1 In this context, it is assumed that the connection processing for side link communication between terminals has been completed, and terminals A 101 and B 102 are in a state where side link communication can be performed between them.

[0014] (Functional configuration of communication equipment) The functional configuration of the communication device according to this embodiment will then be described. Note that the configuration of the functional blocks described below is merely an example.

[0015] A part or all of a functional block can be replaced by other functional blocks that implement similar functions, a part of a functional block can be omitted, or further functional blocks can be added. Furthermore, a functional block described below can be divided into multiple functional blocks, or multiple functional blocks can be integrated into one functional block. Alternatively, only some functional blocks can be composed of hardware, while other functions can be composed of software. When a functional block is composed of software, the processor constituting the control unit 201 described below executes a control program stored in the storage unit 202 described below for implementing the functions. Thus, functionality as a functional block is provided.

[0016] Figure 2 This is a functional block diagram illustrating an example of the functional configuration of terminal A 101 and terminal B 102 according to this embodiment. Figure 2 In this system, control unit 201 controls the operation of the terminal. Storage unit 202 stores information for control of control unit 201 and information about communication.

[0017] The reception quality measurement unit 203 measures the reception quality used to generate a Channel State Information (CSI) report to be sent to the communication counterpart terminal by using a reference signal included in the radio signal transmitted from the communication counterpart terminal. Furthermore, the reception quality measurement unit 203 generates the CSI report to be sent to the communication counterpart terminal based on the measured reception quality. Note that the CSI report may also be referred to as a propagation path information report.

[0018] The precoding setting unit 204 makes judgments and sets settings related to precoding operations based on information related to the CSI report. Additionally, the precoding setting unit 204 sets the precoding for the radio signal to be transmitted to the communication partner terminal based on the CSI report received from the communication partner terminal.

[0019] The message generation unit 205 generates messages to be sent to the communication counterpart terminal, such as a send instruction (CSI report send instruction) to indicate the sending of a CSI report or a precoding setting change notification. The message analysis unit 206 analyzes messages already received from the communication counterpart terminal (such as CSI report send instructions or precoding setting change notifications). Note that the CSI report send instruction can also be referred to as a propagation path information report send instruction.

[0020] Radio communication unit 207 transmits radio signals to and receives radio signals from the counterpart terminal via sidelink communication. Radio communication unit 207 also transmits a CSI report transmission command generated by message generation unit 205 to the counterpart terminal. Radio communication unit 207 also transmits precoded radio signals to and receives precoded radio signals from the counterpart terminal. Furthermore, upon receiving a CSI report transmission command from the counterpart terminal, radio communication unit 207 transmits a CSI report generated by reception quality measurement unit 203 to the counterpart terminal.

[0021] Furthermore, if the precoding is set based on a CSI report received from the other party's terminal and the currently set precoding setting value is changed, the radio communication unit 207 sends a precoding setting change notification to the other party's terminal.

[0022] Furthermore, when setting precoding based on a CSI report received from the other party's terminal, and when the currently set precoding settings have not changed, the radio communication unit 207 does not send a precoding setting change notification to the other party's terminal.

[0023] The communication status judgment unit 208 judges the communication status with the other party terminal through the side link.

[0024] The reception quality measurement unit 203 is an example of a measurement unit. The precoding setting unit 204 is an example of a setting unit. The radio communication unit 207 is an example of a communication unit. The message generation unit 205 is an example of a generation unit. The communication status judgment unit 208 is an example of a judgment unit.

[0025] (Processing Example) Will use Figure 3 The illustrated operation sequence diagram and Figure 4and Figure 5 The illustrated flowchart describes the operation in the first embodiment.

[0026] Figure 3 An example of a sequence representing a process for bidirectional precoding and simultaneous sidelink communication between terminal A 101 and terminal B 102, as illustrated in the first embodiment, is given. Additionally, Figure 4 and Figure 5 Is with Figure 3 The sequence diagram in the diagram corresponds to the flowchart describing the operations of terminal A 101 and terminal B 102.

[0027] Terminal A 101 and Terminal B 102 communicate via Figure 2 The illustrated control unit 201 executes the control program stored in the storage unit 202 to achieve this. Figure 4 and Figure 5 The flowcharts describe the various processes. It is assumed that a portion of the process is implemented in cooperation with the aforementioned hardware and functional units.

[0028] exist Figure 3 In this configuration, terminal A 101 and terminal B 102 are connected via side link communication through their respective radio communication units 207 (F301).

[0029] Terminal A 101 determines the communication status with terminal B 102 (F302, S401). For example, during the processing in F301, terminal A 101 may measure the reception quality of the radio signal received from terminal B 102 and determine the communication status with terminal B 102 based on the measured reception quality. Additionally, if the reception quality is less than or equal to a predetermined threshold, terminal A 101 may determine that the precoding information needs to be updated. Alternatively, if terminal A 101 has moved more than a predetermined distance from a location where precoding information was previously set, terminal A 101 may determine that the precoding information needs to be updated. In F302 and S401, if terminal A 101 determines that the precoding to be used for its own transmissions needs to be updated, terminal A 101 sends a CSI report transmission instruction message to terminal B 102 (F303, S402). The CSI report transmission instruction message may include a pmi-FormatIndicator. The pmi-FormatIndicator provides instructions on whether terminal B 102 should include the PMI corresponding to the broadband in the CSI report or include the PMI for each subband in the CSI report.

[0030] Additionally, terminal A 101 sends a reference signal (F304) to terminal B 102. The reference signal may be, for example, a channel state information reference signal (CSI-RS).

[0031] When a CSI report transmission instruction message is received during processing in S405, terminal B 102 measures the reception quality of the reference signal (F304) transmitted from terminal A 101 (S406). Terminal B 102 generates a CSI report based on information related to the measured reception quality and sends the CSI report to terminal A 101 (F305, S407). Note that sending a CSI report can be referred to as CSI feedback. When a CSI report is received in F305 and S403, terminal A 101 uses the received CSI report to calculate and set precoding information (F306, S404). The CSI report may include, for example, a channel quality indicator (CQI), a coding matrix indicator (PMI), or a rank indicator (RI). Alternatively, terminal A 101 may calculate the precoding information based on the PMI.

[0032] Subsequently, terminal A 101 transmits a radio signal (F307) to terminal B 102 using the configured precoding information. Note that transmitting a radio signal using precoding information means, for example, transmitting a radio signal multiplied by the precoding information (precoding matrix).

[0033] Similarly, terminal B 102 determines the communication status with terminal A 101 (F308, S501). The determination of the communication status can be the same as the determination method performed by terminal A 101 as described in the processing steps of F302 and S401. If terminal B 102 determines in F308 and S501 that it needs to update the precoding to be used for its own transmission, terminal B 102 sends a CSI report transmission instruction message to terminal A 101 (F309, S502). Terminal B 102 also sends a reference signal to terminal A 101 (F310). The reference signal can be, for example, CSI-RS.

[0034] When a CSI report transmission instruction message is received during processing in S505, terminal A 101 measures the reception quality of the reference signal (F310) transmitted from terminal B 102 (S506). Terminal A 101 generates a CSI report based on information related to the measured reception quality and sends the CSI report to terminal B 102 (F311, S507). When a CSI report is received in F312 and S503, terminal B 102 uses the received CSI report to calculate and set precoding information (F312, S504). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal B 102 may calculate the precoding information based on PMI.

[0035] Subsequently, terminal B 102 sends a signal (F313) to terminal A 101 using the precoded information it has set.

[0036] According to the first embodiment described above, terminal A 101 and terminal B 102 perform bidirectional precoding. This enables stable communication even when the communication state between the terminals changes.

[0037] [Second Embodiment] The system configuration and functional configuration of the device according to the second embodiment are similar to those of the first embodiment. (The following will be used...) Figure 6 The illustrated operation sequence diagram and Figure 7 The illustrated flowchart describes the operation in the second embodiment.

[0038] Figure 6 An example sequence illustrating a process for performing bidirectional precoding while simultaneously conducting sidelink communication between terminal A 101 and terminal B 102 is shown. Additionally, Figure 7 Is with Figure 6 The flowcharts corresponding to the sequence content describe the operations of terminal A 101 and terminal B 102.

[0039] Terminal A 101 and Terminal B 102 communicate via Figure 2 The illustrated control unit 201 executes the control program stored in the storage unit 202 to implement the various processes described in the flowchart. It is assumed that a portion of the processing is implemented in cooperation with the aforementioned hardware and functional units.

[0040] exist Figure 6 In this configuration, terminal A 101 and terminal B 102 are connected via side link communication through their respective radio communication units 207 (F601).

[0041] Terminal A 101 determines the communication status with terminal B 102 (F602, S701). The determination of the communication status can be the same as the determination method described in the first embodiment. When terminal A 101 determines in F602 and S701 that it needs to update the precoding to be used for its own transmission, terminal A 101 sends a CSI report transmission instruction message to terminal B 102 (F603, S702). In addition, terminal A 101 sends a reference signal to terminal B 102 (F604). The reference signal can be, for example, CSI-RS.

[0042] Upon receiving a CSI report transmission instruction message, terminal B 102 measures the reception quality of the reference signal (F604) transmitted from terminal A 101. Terminal B 102 sends a CSI report to terminal A 101 based on information related to the measured reception quality (F605). When a CSI report is received in F605 and S703, terminal A 101 uses the received CSI report to calculate and set precoding information (F606, S704). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal A 101 may calculate the precoding information based on PMI. If terminal A 101 changes the set precoding information during the processing in F606 and S704 (S705), terminal A 101 sends a precoding change notification message to terminal B 102 (F607, S706).

[0043] When a precoded change notification message is received from terminal A 101 in F607 (S707), terminal B 102 sends a CSI report transmission instruction message to terminal A 101 (F608, S708). Additionally, terminal B 102 sends a reference signal to terminal A 101 (F609). The reference signal may be, for example, CSI-RS.

[0044] When a CSI report transmission instruction message is received in S608, terminal A 101 measures the reception quality of the reference signal received from terminal B 102. Terminal A 101 generates a CSI report based on information related to the measured reception quality and sends the CSI report to terminal B 102 (F610). When a CSI report is received in F610 and S709, terminal B 102 uses the received CSI report to calculate and set precoding information (F611, S710). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal B 102 may calculate the precoding information based on PMI.

[0045] Subsequently, terminal A 101 sends a signal (F612) to terminal B 102 using the configured precoding information. Additionally, terminal B 102 sends a signal (F613) to terminal A 101 using the configured precoding information.

[0046] In the second embodiment described above, when terminal A 101 changes its precoding information (i.e., when terminal A 101 changes its precoding information due to a change in communication state), terminal A 101 sends a precoding change notification message to terminal B 102 in F607. Additionally, terminal B 102, having already received the precoding change notification message, requests terminal A 101 to send a CSI report to terminal A 101 to update its precoding settings (F608).

[0047] This allows the precoding settings of terminal B 102 to be updated quickly if the precoding settings of terminal A 101 change. It also enables terminal A 101 and terminal B 102 to quickly perform bidirectional synchronous precoding operations, thereby achieving more stable communication than in the first embodiment.

[0048] Figure 8 An example of a message formatting scenario using SCI to notify of precoding change notification messages is illustrated. Setting up a precoding report in SCI enables precoding setting change notifications. Note that the second embodiment illustrates an example of setting a 2-bit field, but the field can be a 1-bit or 3-bit field.

[0049] Figure 9 An example of a message format for using Radio Resource Control (RRC) to notify precoding change notification messages is illustrated. In the ReportConfigNR-SL message of the RRC message, setting reportPrecoding-r16 enables precoding setting change notification.

[0050] [Third Embodiment] The system configuration and functional configuration of the device according to the third embodiment are similar to those of the first embodiment.

[0051] Will use Figure 10 The illustrated operation sequence diagram and Figure 11 The illustrated flowchart describes the operation of the third embodiment.

[0052] Figure 10 An example is given illustrating a sequence of processes used for bidirectional precoding while simultaneously performing sidelink communication between terminal A 101 and terminal B 102. Additionally, Figure 11 Is with Figure 10The flowcharts corresponding to the sequence content describe the operations of terminal A 101 and terminal B 102.

[0053] Terminal A 101 and Terminal B 102 communicate via Figure 2 The illustrated control unit 201 executes the control program stored in the storage unit 202 to implement the various processes described in the flowchart. It is assumed that a portion of the processing is implemented in cooperation with the aforementioned hardware and functional units.

[0054] exist Figure 10 In this configuration, terminal A 101 and terminal B 102 are connected via side link communication through their respective radio communication units 207 (F1001).

[0055] Terminal A 101 determines the communication status with terminal B 102 (F1002, S1101). The determination of the communication status can be the same as the determination method described in the first embodiment. When terminal A 101 determines in F1002 and S1101 that it needs to update the precoding to be used for its own transmission, terminal A 101 sends a CSI report transmission instruction message to terminal B 102 (F1003, S1102). In addition, terminal A 101 sends a reference signal to terminal B 102 (F1004). The reference signal can be, for example, CSI-RS.

[0056] Upon receiving a CSI report transmission command message, terminal B 102 measures the reception quality of the reference signal (F1004) received from terminal A 101. Terminal B 102 generates a CSI report based on information related to the measured reception quality and sends the CSI report (F1005) to terminal A 101. Additionally, after sending the CSI report, terminal B 102 sends a reference signal (F1007) to terminal A 101. The reference signal may be, for example, CSI-RS.

[0057] When a CSI report is received in F1005 and S1103, terminal A 101 uses the received CSI report to calculate and set precoding information (F1006, S1104). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal A 101 may calculate the precoding information based on PMI.

[0058] If, during the processing of F1006 and S1104, terminal A 101 has changed the set precoding information (S1105), terminal A 101 measures the reception quality of the reference signal received from terminal B 102 (F1007). Furthermore, terminal A 101 creates a CSI report based on the measured reception quality and sends the created CSI report, along with a precoding change notification message, to terminal B 102 (F1008, S1106). When the precoding change notification message and CSI report are received from terminal A 101 in F1108 and S1107, terminal B 102 uses the received CSI report to calculate and set the precoding information (F1009, S1108). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal B 102 may calculate the precoding information based on PMI. Subsequently, terminal A 101 sends a signal (F1010) to terminal B 102 using the configured precoding information. Additionally, terminal B 102 sends a signal (F1011) to terminal A 101 using the configured precoding information.

[0059] In the third embodiment described above, after sending a CSI report to terminal A 101, terminal B 102 also sends a reference signal (F1007). Furthermore, if terminal A 101 changes the precoding information settings based on the received CSI report, terminal A 101 measures the reference signal (F1007) sent from terminal A 101 and sends both a precoding change notification and a CSI report (F1008) to terminal B 102.

[0060] This allows the precoding settings of terminal B 102 to be updated even more quickly than in the second embodiment, should the precoding settings of terminal A change. It also enables terminal A 101 and terminal B 102 to perform bidirectional synchronous precoding operations more quickly, resulting in even more stable communication than in the second embodiment.

[0061] [Fourth Embodiment] The system configuration and functional configuration of the device according to the fourth embodiment are similar to those of the first embodiment.

[0062] Will use Figure 12 The illustrated operation sequence diagram and Figure 13 The illustrated flowchart describes the operation of the fourth embodiment.

[0063] Figure 12 An example is given illustrating a sequence of processes used for bidirectional precoding while simultaneously performing sidelink communication between terminal A 101 and terminal B 102. Additionally, Figure 13 Is with Figure 11The flowcharts corresponding to the sequence content describe the operations of terminal A 101 and terminal B 102.

[0064] Terminal A 101 and Terminal B 102 communicate via Figure 2 The illustrated control unit 201 executes the control program stored in the storage unit 202 to implement the various processes described in the flowchart. It is assumed that a portion of the processing is implemented in cooperation with the aforementioned hardware and functional units.

[0065] exist Figure 12 In this configuration, terminal A 101 and terminal B 102 are connected via their respective radio communication units 207 through side link communication (F1201).

[0066] Terminal A 101 determines the communication status with terminal B 102 (F1202, S1301). The determination of the communication status can be the same as the determination method described in the first embodiment. When terminal A 101 determines in F1202 and S1301 that it needs to update the precoding to be used for its own transmission, terminal A 101 sends a CSI report transmission instruction message to terminal B 102 (F1203, S1302). In addition, terminal A 101 sends a reference signal to terminal B 102 (F1204). The reference signal can be, for example, CSI-RS.

[0067] Upon receiving a CSI report transmission instruction message (F1203, S1307), terminal B 102 measures the reception quality of the reference signal (F1204) received from terminal A 101 (S1308). Subsequently, terminal B 102 generates a CSI report based on information related to the measured reception quality and sends the CSI report to terminal A 101 (F1205, S1309). Furthermore, after sending the CSI report and before completing the precoding settings update (i.e., after completing...), Figure 12 Before the processing of F1209 in the process, terminal B102 sends a reference signal (F1206) to terminal A101. The reference signal can be, for example, CSI-RS.

[0068] On the other hand, terminal A 101 measures the reception quality of the reference signal (F1206) sent from terminal B 102 (S1305), generates a CSI report based on information related to the measured reception quality, and sends the CSI report to terminal B 102 (F1207, S1306).

[0069] Terminal A 101 uses the CSI reports received in F1205 and S1303 to calculate and set precoding information (F1208, S1304). The CSI reports may include, for example, CQI, PMI, and RI. Alternatively, terminal A 101 may calculate the precoding information based on PMI.

[0070] exist Figure 12 In the example, the process in F1208 is shown to be executed after the process in F1207, but the order is not limited to this. Similar to... Figure 10 Terminal A 101 can also execute the processing procedure in F1208 after receiving the CSI report from terminal B 102 (i.e., after the processing procedure in F1205).

[0071] Similarly, terminal B 102 uses the CSI reports received in F1207 and S1310 to calculate and set precoding information (F1209, S1311). The CSI report may include, for example, CQI, PMI, and RI. Alternatively, terminal B 102 may calculate the precoding information based on PMI. Thereafter, terminal A 101 sends a signal to terminal B 102 using the set precoding information (F1210). Additionally, terminal B 102 sends a signal to terminal A 101 using the set precoding information (F1211).

[0072] In the fourth embodiment described above, after sending a CSI report to terminal A 101, terminal B 102 also sends a reference signal (F1206). Additionally, terminal A 101 measures the reference signal (F1206) sent from terminal B 102 and sends a CSI report (F1207) to terminal B 102.

[0073] In the fourth embodiment, since terminal A 101 does not send precoding change notifications to terminal B 102, the processing load on terminal A 101 can be reduced. This allows terminal A 101 and terminal B 102 to perform bidirectional synchronous precoding operations more quickly, thereby enabling even more stable communication than in the second embodiment.

[0074] [Other Embodiments] According to the present invention, a program for implementing one or more functions of the first to fourth embodiments described above is provided to a system or device via a network or storage medium. The present invention can also be implemented by one or more processors in the system or device reading and executing the program. Alternatively, the present invention can also be implemented by a circuit (e.g., an application-specific integrated circuit (ASIC)) implementing one or more functions.

[0075] This invention is not limited to the embodiments described above, and various changes and modifications can be made to the invention without departing from its spirit and scope. Therefore, the claims are appended hereto disclose the scope of the invention.

[0076] Note that the following notes are provided in connection with the above embodiments.

[0077] [Postscript 1] A communication device for communicating with a counterparty terminal, the communication device comprising: Communication unit, used for: Sending precoded radio signals to the communication counterpart terminal and receiving precoded radio signals from the communication counterpart terminal, and Send a transmission command to the communication counterpart terminal to instruct the transmission of a propagation path information report; and The setting unit is used to set the precoding of the radio signal to be sent to the communication counterpart terminal based on the propagation path information report received from the communication counterpart terminal.

[0078] [Postscript 2] According to the communication device described in Appendix 1, when the communication unit receives a transmission instruction from the communication counterpart terminal for instructing the transmission of the propagation path information report, the communication unit transmits the propagation path information report to the communication counterpart terminal.

[0079] [Postscript 3] According to the communication device described in Appendix 1 or 2, when the precoding is set based on the propagation path information report received from the communication counterpart terminal, and when the currently set precoding setting value is changed, the communication unit sends a precoding setting change notification to the communication counterpart terminal.

[0080] [Postscript 4] According to any one of Appendices 1 to 3, in the case where the precoding is set based on the propagation path information report received from the communication counterpart terminal, and where the currently set precoding setting value has not changed, the communication unit does not send a precoding setting change notification to the communication counterpart terminal.

[0081] [Postscript 5] According to the communication device described in Appendix 3 or 4, the communication unit uses side link control information, i.e., SCI, to send the precoding setting change notification.

[0082] [Postscript 6] According to the communication device described in Appendix 3 or 4, the communication unit uses Radio Resource Control (RRC) messages to send the precoding setting change notification.

[0083] [Postscript 7] According to the communication device described in Appendix 3 or 4, in addition to the precoding setting change notification, the communication unit also sends the propagation path information report to the communication counterpart terminal.

[0084] [Postscript 8] A communication method executed by a communication device for communicating with a communication counterpart terminal, the communication method comprising: Sending precoded radio signals to and receiving the precoded radio signals from the communication counterpart terminal, and sending a transmission command to the communication counterpart terminal to instruct the transmission of a propagation path information report; and Based on the propagation path information report received from the communication counterpart terminal, precoding is set for the radio signal to be sent to the communication counterpart terminal.

[0085] [Postscript 9] A program that is executed by a communication device for communicating with a terminal of another communication partner: Sending precoded radio signals to and receiving the precoded radio signals from the communication counterpart terminal, and sending a transmission command to the communication counterpart terminal to instruct the transmission of a propagation path information report; and Based on the propagation path information report received from the communication counterpart terminal, precoding is set for the radio signal to be sent to the communication counterpart terminal.

[0086] [Postscript 10] A communication system comprising a plurality of communication devices according to Appendix 1.

[0087] This application claims the benefit of Japanese Patent Application 2024-039193, filed with the Japan Patent Office on March 13, 2024, the entire contents of which are incorporated herein by reference. Explanation of reference numerals in the attached figures

[0088] Terminal A, 101 102 Terminal B

Claims

1. A communication device for communicating with a counterparty terminal, the communication device comprising: Communication unit, used for: Sending precoded radio signals to the communication counterpart terminal and receiving precoded radio signals from the communication counterpart terminal, and Send a sending instruction to the communication counterpart terminal to instruct the transmission of a propagation path information report; as well as The setting unit is used to set the precoding of the radio signal to be sent to the communication counterpart terminal based on the propagation path information report received from the communication counterpart terminal.

2. The communication device according to claim 1, wherein, When the communication unit receives a sending instruction from the communication counterpart terminal to instruct the transmission path information report, the communication unit sends the transmission path information report to the communication counterpart terminal.

3. The communication device according to claim 1, wherein, When the precoding is set based on the propagation path information report received from the communication counterpart terminal, and when the currently set precoding setting value is changed, the communication unit sends a precoding setting change notification to the communication counterpart terminal.

4. The communication device according to claim 1, wherein, When the precoding is set based on the propagation path information report received from the communication counterpart terminal, and the currently set precoding setting value has not changed, the communication unit does not send a precoding setting change notification to the communication counterpart terminal.

5. The communication device according to claim 3, wherein, The communication unit uses Side Link Control Information (SCI) to send the precoding setting change notification.

6. The communication device according to claim 3, wherein, The communication unit uses Radio Resource Control (RRC) messages to send the precoding setting change notification.

7. The communication device according to claim 3, wherein, In addition to the precoding setting change notification, the communication unit also sends the propagation path information report to the communication counterpart terminal.

8. A communication method performed by a communication device, the communication device being used to communicate with a communication counterpart terminal, the communication method comprising: Sending a precoded radio signal to the communication counterpart terminal and receiving the precoded radio signal from the communication counterpart terminal, and sending a transmission instruction to the communication counterpart terminal to indicate the transmission of a propagation path information report; as well as Based on the propagation path information report received from the communication counterpart terminal, precoding is set for the radio signal to be sent to the communication counterpart terminal.

9. A program that is executed by a communication device for communicating with a communication counterpart terminal: Sending precoded radio signals to and receiving the precoded radio signals from the communication counterpart terminal, and sending a transmission command to the communication counterpart terminal to instruct the transmission of a propagation path information report; and Based on the propagation path information report received from the communication counterpart terminal, precoding is set for the radio signal to be sent to the communication counterpart terminal.

10. A communication system comprising a plurality of communication devices according to claim 1.

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