Communication device, communication system, control method, and program

Abstract

To provide a mechanism that allows report of propagation information in a mode for reducing the influence of the movement of a terminal and reduces deterioration of precoding performance.SOLUTION: A communication device is disclosed comprising: receiving means that receives a propagation path information report including an identifier with which whether a report is for sub-band precoding or for wide-band precoding can be identified; identification means that identifies whether the report is for sub-band precoding or for wide-band precoding on the basis of the identifier; generation means that executes precoding of transmission data according to a result of identification performed by the identification means; and transmission means that transmits the transmission data generated by the generation means.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] In wireless communications, there is a precoding technology that generates a signal that takes current propagation path information into account on the transmitting side to improve transmission efficiency. When precoding is performed between a base station conforming to the 3GPP (3rd Generation Partnership Project) (registered trademark) standard and a terminal, the base station determines instructions to the terminal depending on the communication status with the terminal, and then transmits a reference signal and a report instruction. The terminal then reports propagation path information to the base station using a report configuration based on this report instruction (see, for example, Patent Document 1). Based on this reported propagation path information, the base station transmits precoded data. Examples of report instructions include a wideband that represents a communication bandwidth (e.g., 20 MHz) using one piece of propagation path information, and a subband that divides the same communication bandwidth into multiple bandwidths and represents multiple pieces of propagation path information. Furthermore, precoding has not been performed between terminals conforming to the 3GPP standard in the past. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-100274 Summary of the Invention [Problem to be solved by the invention]

[0004] When implementing precoding communication between terminals that conform to the 3GPP standard, the following problems arise. In terminal-to-terminal communication, unlike base station-to-terminal communication, both terminals may be moving. It takes a certain amount of time to determine the instructions to send to the terminal based on the communication conditions. However, in terminal-to-terminal communication, when the terminals are moving, the communication conditions may fluctuate more significantly than in base station-to-terminal communication. As a result, the determined instructions may not be appropriate at that time, which could result in a degradation of precoding performance.

[0005] The present invention has been made in consideration of at least one of the above-mentioned problems, and an object of the present invention is to provide a mechanism that enables reporting of channel information in a manner that is less susceptible to the influence of terminal movement and reduces degradation of precoding performance. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a communication device, comprising: a receiving means for receiving a channel state report including an identifier for identifying whether the channel state report is for subband precoding or wideband precoding; Identification means for identifying whether the signal is for subband precoding or wideband precoding based on the identifier; generating means for performing precoding of transmission data in accordance with the identification result of the identifying means; The data transmission system is characterized by comprising a transmitting means for transmitting the transmission data generated by the generating means. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to provide a mechanism that enables reporting of propagation path information in a manner that is less susceptible to the influence of terminal movement and reduces degradation of precoding performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is a diagram illustrating an example of a reporting configuration of propagation path information for subbands. [Figure 2] FIG. 10 is a diagram illustrating an example of a reporting configuration of propagation path information for wideband. [Figure 3] FIG. 2 is a block diagram illustrating a configuration of a terminal according to the first embodiment. [Figure 4] FIG. 2 is a software functional block diagram of a terminal according to the first embodiment. [Figure 5] 1 is a configuration diagram of a wireless communication system according to a first embodiment. [Figure 6] FIG. 10 is a diagram illustrating processing on the reference signal receiving side in the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating a reporting configuration of propagation path information for subbands in the first embodiment. [Figure 8] FIG. 10 is a diagram illustrating a reporting configuration of propagation path information for wideband in the first embodiment. [Figure 9] FIG. 10 is a diagram illustrating processing on the reference signal transmitting side in the first embodiment. [Figure 10] FIG. 10 is a diagram illustrating processing on the reference signal transmitting side in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. In the following description, the "number ***" in TS*** represents the number of the technical specification in the 3GPP standard.

[0010] As explained in the "Problem to be Solved by the Invention" section above, unlike base station-terminal communication, in terminal-to-terminal communication, both terminals may be in motion. It takes a certain amount of time to determine the instructions to be given to the terminal depending on the communication situation. Note that terminal-to-terminal communication may be communication via a PC5 interface (for example, an air interface between V2X (Vehicle to Everything) devices).

[0011] On the other hand, if report contents are configured autonomously instead of based on a report instruction, configuring the report contents does not take a relatively long time. Specifically, this is because, when report contents are configured based on a report instruction or autonomously, it takes extra time from receiving a report instruction to receiving a reference signal for CSI measurement. Note that, when based on a report instruction, a CSI (Channel State Information) report (an example of a propagation path information report) is implemented in an aperiodic or semi-persistent manner. Note that, when report contents are configured autonomously, a CSI report is implemented in a periodic manner. However, with the current reporting configuration, it is not possible to distinguish whether the report is for a wideband or a subband. In particular, when the reporting configuration for a subband is as shown in FIG. 1 and the reporting configuration for a wideband is as shown in FIG. 2, the first two fields (CRI and Rank Indicator) are the same, making it difficult to immediately distinguish. Note that CRI is an abbreviation for Channel state information-reference signal Resource Indicator.

[0012] Each of the embodiments described below aims to solve at least part of these problems.

[0013] [First embodiment] FIG. 3 is a diagram showing an example of the functional configuration of the terminal 30 according to this embodiment.

[0014] Reference numeral 301 denotes a control unit that controls itself by executing a control program stored in a storage unit 302. Reference numeral 302 denotes a storage unit that stores the control program executed by the control unit 301 and various information such as communication parameters. Various operations described below are performed by the control unit 301 executing the control program stored in the storage unit 302. Reference numeral 303 denotes a radio receiving unit for receiving signals conforming to the 3GPP standard. Reference numeral 304 denotes a radio transmitting unit for transmitting signals conforming to the 3GPP standard.

[0015] An output unit 305 performs various outputs and has a function of outputting visually perceptible information such as an LCD (Liquid Crystal Display) or LED (Light Emitting Diode), or audible output such as a speaker. The output unit 305 has a function of outputting at least either visual information or audible information. An input unit 306 allows the user to perform various inputs or acquire sensor information.

[0016] FIG. 4 is a block diagram showing an example of the configuration of software functional blocks of the terminal 30. As shown in FIG.

[0017] 401 indicates the entire software function block.

[0018] 402 is a signal transmission unit that transmits signals conforming to the 3GPP standard.

[0019] 403 is a signal receiving unit that receives signals conforming to the 3GPP standard.

[0020] 404 is a data storage unit that stores and holds information such as the software itself and authentication information.

[0021] An input / output control unit 405 controls the output unit 305 and the input unit 306 .

[0022] A CSI table format identification unit 406 identifies the format in which the CSI for conveying channel information is configured. The CSI table format identification unit 406 identifies whether the CSI report is for subband precoding or wideband precoding based on table identification information (described later) included in the CSI report.

[0023] Reference numeral 407 denotes a precoding designation unit for designating whether to perform precoding processing based on a wideband CSI report, precoding processing based on a subband CSI report, or no precoding processing.

[0024] A precoding implementation unit 408 executes precoding in accordance with the designation by the precoding designation unit 407 .

[0025] A subband SINR determination unit 409 determines the SINR, which is the signal-to-interference-plus-noise ratio, for the subband currently used in communication. SINR stands for Signal-to-Interference-plus-Noise Ratio.

[0026] Fig. 5 is a diagram showing an example of the configuration of a wireless communication system according to this embodiment. As shown in Fig. 5, the wireless communication system according to this embodiment has terminal 30A and terminal 30B. Note that, although there may actually be a large number of terminals, Fig. 5 shows only the configuration necessary for explaining this embodiment.

[0027] Hereinafter, we will mainly describe the case where terminal 30A first transmits a reference signal, then terminal 30B transmits a CSI report based on the received reference signal, and then terminal 30A performs precoding based on the received CSI report and transmits data.

[0028] FIG. 6 is a flowchart showing the reference signal receiving process performed in the terminal 30B of this embodiment.

[0029] Here, when terminal 30B receives a reference signal (“YES” in S600) while in a reference signal reception waiting state (“NO” in S600), it generates a CSI report (S601). If the CSI report is for subband precoding, it has a format as shown in FIG. 7, and the first field contains a value of 0x01 as table identification information. If the CSI report is for wideband precoding, it has a format as shown in FIG. 8, and the first field contains a value of 0x02 as table identification information.

[0030] The terminal 30B determines whether to use the table for subband precoding (whether to use the table for wideband precoding), and sets the table identification information to either 0x01 or 0x02 depending on the result of the determination. Note that the method of determination here is arbitrary, and may be determined depending on the state of the radio wave propagation environment, for example.

[0031] Terminal 30B transmits the generated CSI report to terminal 30A (S602). This enables terminal 30A to determine whether the CSI report is for subband preceding or wideband preceding, based on only the first field.

[0032] FIG. 9 is a flowchart showing a reference signal transmitting process performed in the terminal 30A of this embodiment.

[0033] Here, terminal 30A first transmits a reference signal (S901) and waits until it receives a CSI report from terminal 30B (S902). Note that at this time, terminal 30A transmits only a reference signal to terminal 30B, and does not transmit a report instruction.

[0034] If the determination result in S902 is Yes, the CSI table format identification unit 406 is used to determine whether the table identification information of the CSI report includes 0x01 (S903).

[0035] If the determination result in S903 is Yes, the CSI report is for subband precoding, so precoding using information for subband precoding is performed (S904), and the data is transmitted (S906).

[0036] If the determination result in S903 is No, precoding using the information for wideband precoding is performed (S905), and data is transmitted (S906).

[0037] The processes of S904 and S905 are performed by the precoding designation unit 407 designating whether subband precoding or wideband precoding is to be performed.

[0038] As a result, it becomes possible to transmit appropriate CSI reports in terminal-to-terminal communications that comply with the 3GPP standard, thereby reducing degradation in precoding performance.

[0039] In this embodiment, the roles of the receiver and transmitter of the reference signal are separated. However, the receiver and transmitter processes may be executed in parallel between the same terminals.

[0040] [Second embodiment] In the second embodiment, the functional configuration of the terminal, the configuration of the software function blocks of the terminal, the configuration of the network, the processing on the reference signal receiving side, the format for subband precoding, and the format for wideband precoding are as shown in Figures 3 to 8, as in the first embodiment.

[0041] 10 is a flowchart showing the processing on the reference signal transmission side performed by the terminal 30A of this embodiment. Here, the processing of steps S901, S902, and S903 is the same as in the first embodiment, so the same reference numerals are used and the description will be omitted.

[0042] If the determination result in S903 is Yes, the subband SINR determination unit 409 is used to determine whether the SINR value (an example of a value in a propagation path information report) of the subband currently being used in communication is equal to or greater than 3 dB (an example of a predetermined value) (S1004).

[0043] If the determination result in S903 is No, the CSI table format identification unit 406 is used to determine whether the table identification information of the CSI report includes 0x02 (S1005).

[0044] If the determination result in S1004 is Yes, precoding using the subband information is performed (S1006), and data is transmitted (S1009).

[0045] If the determination result in S1004 is No, precoding using wideband information is performed (S1007), and data is transmitted (S1009). This is possible because the reporting structure of the propagation path information for the subband includes the propagation path information for the wideband.

[0046] If the determination result in S1005 is Yes, precoding using the wideband information is performed (S1007), and data is transmitted (S1009).

[0047] If the result of the determination in S1005 is No, it is decided not to perform precoding (S1008), and data is transmitted (S1009).

[0048] Note that steps S1005, S1007, and S1008 are processed by the precoding designation unit 407 designating whether to perform subband precoding, wideband precoding, or no precoding.

[0049] As described above, when the SINR of the currently used subband is not good, i.e., when it is less than 3 dB in this embodiment, another method, i.e., wideband precoding is used in this embodiment, with the aim of improving transmission efficiency. Note that, although this embodiment describes using wideband precoding when the SINR of the currently used subband is not good, a method that does not perform precoding may also be adopted.

[0050] In the first and second embodiments, a terminal that receives a reference signal autonomously transmits a CSI report, and the report includes an identifier of whether the CSI report is wideband information or subband information. However, the CSI report may be transmitted not only after receiving a reference signal but also after receiving an instruction to transmit the CSI report. In this case, the CSI report may include an identifier of whether the CSI report is wideband information or subband information.

[0051] (Other embodiments) In this embodiment, a recording medium storing software program code for implementing the above-described functions may be supplied to a system or device, and the computer (CPU, MPU) of the system or device may read and execute the program code stored on the recording medium. Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes this embodiment. The functions can also be implemented by a circuit (e.g., an ASIC or FPGA) that implements one or more functions. Note that ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array. Furthermore, some or all of the various processes described in the above flowcharts can be implemented by a hardware circuit cooperating with a processor such as a CPU or MPU.

[0052] Examples of storage media that can be used to supply the program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD (Compact Disc)-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, etc. Also usable are ROMs (Read Only Memory), DVDs (Digital Versatile Discs), HDDs (Hard Disk Drives), SSDs (Solid State Drives), etc.

[0053] In addition, the above-mentioned functions may be realized not only by the computer executing the read program code, but also by the operating system (OS) running on the computer performing some or all of the actual processing based on the instructions of the program code. OS is an abbreviation for Operating System.

[0054] Furthermore, the program code read from the storage medium may be written to a memory provided on a function expansion board inserted into a computer or a function expansion unit connected to the computer, and a CPU provided on the function expansion board or function expansion unit may then perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0055] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0056] The following additional notes are also provided regarding the above embodiments:

[0057] [Appendix 1] A receiving means for receiving a channel information report including an identifier that can identify whether the channel information report is for subband precoding or wideband precoding; Identification means for identifying whether the signal is for subband precoding or wideband precoding based on the identifier; generating means for performing precoding of transmission data in accordance with the identification result of the identifying means; a transmitting unit that transmits the transmission data generated by the generating unit. [Appendix 2] The communication device according to claim 1, wherein the generating means performs precoding based on subband information when the channel state report includes a first identifier as the identifier. [Appendix 3] 3. The communication device according to claim 1, wherein the generating means performs precoding based on wideband information when the propagation path information report does not include a first identifier as the identifier. [Appendix 4] The communication device according to any one of Supplementary notes 1 to 3, characterized in that the generation means performs precoding based on wideband information when the propagation path information report includes a second identifier as the identifier. [Appendix 5] 5. The communication device according to claim 1, wherein the generation means performs precoding based on wideband information when the channel state report includes a first identifier as the identifier and a value of the channel state report for a currently used subband is lower than a predetermined value. [Appendix 6] The communication device according to any one of Supplementary Notes 1 to 5, wherein the generation means does not perform precoding when the channel state report includes a first identifier as the identifier and the value of the channel state report for the currently used subband is lower than a predetermined value. [Appendix 7] The communication device according to any one of Supplementary Notes 1 to 6, wherein the transmitting means transmits data using a subband with relatively better channel characteristics when the channel information report includes a first identifier as the identifier and the channel information report value of the currently used subband is lower than a predetermined value. [Appendix 8] the receiving means receives the propagation path information report from another mobile communication device; 8. The communication device according to claim 1, wherein the transmitting means transmits the transmission data to the other communication device. [Appendix 9] A communication device comprising: a transmitting means for transmitting a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding. [Appendix 10] a first communication device, which is a communication device according to any one of Supplementary Notes 1 to 8; a second communication device, the second communication device being the communication device of Supplementary Note 9; The first communication device transmits a reference signal; The second communication device transmits the channel state report to the first communication device in response to the reference signal. [Appendix 11] The communication system described in Supplementary Note 10, characterized in that the identifier is placed before a field indicating a CRI (Channel state information-reference signal Resource Indicator). [Appendix 12] 11. The communication system of claim 10, wherein the identifier is placed before a field indicating a Rank Indicator. [Appendix 13] A control method for controlling communication, comprising: A receiving step of receiving a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding; An identification step of identifying whether the signal is for subband precoding or wideband precoding based on the identifier; a generating step of performing precoding of transmission data according to the identification result of the identifying step; a transmission step of transmitting the transmission data generated in the generation step. [Appendix 14] A receiving step of receiving, by a computer, a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding; An identification step of identifying whether the signal is for subband precoding or wideband precoding based on the identifier; a generating step of performing precoding of transmission data according to the identification result of the identifying step; a transmission step of transmitting the transmission data generated in the generation step; [Explanation of symbols]

[0058] 30A, 30B terminals 402 signal transmission unit (an example of a transmission means) 403 Signal receiving unit (an example of receiving means) 404 Data Storage Unit 405 Input / Output Control Unit 406 CSI table format identification unit (an example of an identification means) 407 Precoding specification part 408 Precoding processing unit (an example of a generating means) 409 Subband SINR decision unit

Claims

1. A receiving means for receiving a channel information report including an identifier that can identify whether the channel information report is for subband precoding or wideband precoding; Identification means for identifying whether the signal is for subband precoding or wideband precoding based on the identifier; generating means for performing precoding of transmission data in accordance with the identification result of the identifying means; a transmitting unit that transmits the transmission data generated by the generating unit.

2. The communication device according to claim 1 , wherein the generating unit performs precoding based on subband information when the channel state report includes a first identifier as the identifier.

3. The communication device according to claim 1 , wherein the generating unit performs precoding based on wideband information when the channel state report does not include a first identifier as the identifier.

4. The communication device according to claim 1 , wherein the generating unit performs precoding based on wideband information when the channel state report includes a second identifier as the identifier.

5. 2. The communication device according to claim 1, wherein the generation means performs precoding based on wideband information when the channel state report includes a first identifier as the identifier and a value of the channel state report for a currently used subband is lower than a predetermined value.

6. 2. The communication device according to claim 1, wherein the generation means does not perform precoding when the channel state report includes a first identifier as the identifier and a value of the channel state report for a currently used subband is lower than a predetermined value.

7. 2. The communication device according to claim 1, wherein the transmitting means transmits data using a subband with relatively better channel characteristics when the channel state report includes a first identifier as the identifier and a value of the channel state report for a currently used subband is lower than a predetermined value.

8. the receiving means receives the propagation path information report from another mobile communication device; 2. The communication device according to claim 1, wherein said transmitting means transmits said transmission data to said other communication device.

9. A communication device comprising: a transmitting means for transmitting a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding.

10. a first communication device, which is a communication device according to any one of claims 1 to 8; a second communication device that is the communication device according to claim 9; The first communication device transmits a reference signal; The second communication device transmits the channel state report to the first communication device in response to the reference signal.

11. 11. The communication system according to claim 10, wherein the identifier is placed before a field indicating a channel state information-reference signal resource indicator (CRI).

12. 11. The communication system according to claim 10, wherein the identifier is placed before a field indicating a Rank Indicator.

13. A control method for controlling communication, comprising: A receiving step of receiving a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding; An identification step of identifying whether the signal is for subband precoding or wideband precoding based on the identifier; a generating step of performing precoding of transmission data according to the identification result of the identifying step; a transmission step of transmitting the transmission data generated in the generation step.

14. A receiving step of receiving, by a computer, a channel information report including an identifier that enables identification of whether the channel information report is for subband precoding or wideband precoding; An identification step of identifying whether the signal is for subband precoding or wideband precoding based on the identifier; a generating step of performing precoding of transmission data according to the identification result of the identifying step; a transmission step of transmitting the transmission data generated in the generation step;

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