Terminal device, relay device, control method, and program in wireless communication system using relay device as extension antenna for terminal device

Abstract

To allow a terminal device to communicate with a base station device by using a relay device having an RF relay function as an extended antenna.SOLUTION: There is provided a terminal device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency, amplifies the signal, and relays the signal to the base station device, and converts a signal of a second frequency transmitted by the base station device to the first frequency, amplifies the signal, and relays the signal to the terminal device. The relay device has a relay function that converts the frequency of a received signal and amplifies the signal, and relays the signal without demodulating or decoding the signal, and a communication function that communicates with the terminal device and is different from the relay function. The terminal device acquires capability information related to the relay function of the relay device via the communication function of the relay device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wireless communication system in which a relay device is used as an extension antenna for a terminal device. [Background technology]

[0002] As a technology for the sixth generation cellular communication system, a technology is being considered in which a relay device having a radio frequency (RF) relay function is used as an extended antenna capable of beamforming (see Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] K. Yamazaki, T. Ohseki, Y. Amano, H. Shinbo, T. Murakami, and Y. Kishi, “Proposal for a User-Centric Ran Architecture Towards Beyond 5G”, 2021 ITU Kaleidoscope: Connecting Physical and Virtual Worlds (ITU K), February 2021. Summary of the Invention [Problem to be solved by the invention]

[0004] There has been little progress in studying specific methods for using such relay devices as extension antennas in cellular communication systems. [Means for solving the problem]

[0005] The present invention provides a control technique for a terminal device to communicate with a base station device using a relay device having an RF relay function as an extension antenna.

[0006] A terminal device according to one embodiment of the present invention is a terminal device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency and amplifies it to relay it to the base station device, and converts the signal of the second frequency transmitted by the base station device to the first frequency and amplifies it to relay it to the terminal device, wherein the relay device has relay means that converts the frequency of a received signal and amplifies it, and relays the signal without demodulating or decoding it, and a communication means that communicates with the terminal device and is different from the relay means, and the terminal device has an acquisition means that acquires capability information regarding the relay means of the relay device via the communication means of the relay device.

[0007] A relay device according to one embodiment of the present invention is a relay device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency and amplifies it to relay it to the base station device, and converts a signal of the second frequency transmitted by the base station device to the first frequency and amplifies it to relay it to the terminal device, the relay device having a relay means that converts the frequency of a received signal and amplifies it, and relays the signal without demodulating or decoding it, and a communication means that communicates with the terminal device and is different from the relay means, and the communication means notifies the terminal device of capability information regarding the relay means of the relay device. Effect of the Invention

[0008] According to the present invention, a terminal device can communicate with a base station device by using a relay device having an RF relay function as an extension antenna. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Diagram 2]11 is a diagram illustrating an example of a processing flow in which a terminal device acquires capability information of a relay device. [Diagram 3] 11 is a diagram showing an example of a process flow in which a terminal device actively notifies a base station device of capability information. [Figure 4] 11 is a diagram showing an example of a processing flow in which a terminal device identifies detailed states of a transmission path between the terminal device, a base station device, and a relay device. [Diagram 5] 1 is a diagram showing one example of the configuration of a relay device that converts the frequency of a signal received from a terminal device into one of a plurality of frequencies. [Figure 6] 11 is a diagram illustrating an example of a process flow for controlling a conversion destination of a frequency of a wireless signal in a relay device. [Figure 7] 11 is a diagram illustrating an example of a process flow in which a terminal device detects a relay device having only a relay function. [Figure 8] FIG. 2 is a diagram illustrating an example of a hardware configuration of a terminal device and a relay device. [Figure 9] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal device. [Figure 10] FIG. 2 illustrates an example of a functional configuration of a portion of a relay device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] (System Configuration) Fig. 1 shows an example of the configuration of a wireless communication system according to this embodiment. In this wireless communication system, a terminal device 101 is connected to multiple relay devices 121 and 122, and the relay devices 121 and 122 relay communication between the terminal device 101 and a base station device 151. The terminal device 101 and the base station device 151 are wireless communication devices that comply with the 5th generation (5G) or later cellular communication standard of the 3rd Generation Partnership Project (3GPP (registered trademark)), for example. Note that Fig. 1 shows an example in which there is one each of the terminal device 101 and the base station device 151, but it is naturally assumed that there are many of these communication devices.

[0012] In this embodiment, the relay devices 121 and 122 are connected to the terminal device 101 and operate to function as pseudo antennas extended from the terminal device 101 by relaying only communications involving the terminal device 101. That is, the relay devices 121 and 122 function as extended antennas (extended antennas) of the terminal device 101, and are configured to use wireless communication between the terminal device 101 and the relay devices 121 and 122 instead of cables. As a result, the terminal device 101 communicates with the base station device 151 using the relay devices 121 and 122 as antennas provided in the terminal device. The base station device 151 does not recognize the relay devices 121 and 122 individually. That is, the terminal device 101 and the relay devices 121 and 122 are combined to operate as a virtual terminal device. In the following, the relay devices 121 and 122 may be called virtual antennas because they function as antennas of the virtual terminal device. More precisely, each of one or more antennas possessed by the relay devices 121 and 122 is used as a virtual antenna, but when there is no need to distinguish between them, the relay devices 121 and 122 that perform relay transmission may be called a virtual antenna (it may be said that the relay devices 121 and 122 function as virtual antennas). The relay devices 121 and 122 are configured to relay only communications involving the terminal device 101, and do not relay communications of other terminal devices. The relay devices 121 and 122 may be, for example, wireless devices held by users, such as smart watches, but are not limited thereto.

[0013] The relay devices 121 and 122 amplify a radio signal transmitted from the terminal device 101 and relay it to the base station device 151, and also amplify a radio signal transmitted from the base station device 151 and relay it to the terminal device 101. The relay devices 121 and 122 do not demodulate and decode the radio signal transmitted between the terminal device 101 and the base station device 151. That is, the relay devices 121 and 122 have a radio frequency (RF) relay function (function as a radio repeater). Here, the signal 111 transmitted and received between the terminal device 101 and the relay devices 121 and 122 is transmitted over a short-distance communication line using a high frequency band (Terahertz (THz) band) such as the 300 GHz band. On the other hand, the signal 141 transmitted and received between the relay devices 121 and 122 and the base station device 151 is transmitted over a relatively long-distance communication line using a relatively low frequency band (millimeter wave band) such as the 39 GHz band. That is, the relay devices 121 and 122 convert signals received in a first frequency band (THz band) for communication with the terminal device 101 to a second frequency band (millimeter wave band) for communication with the base station device 151 and relay the converted signals, and also convert signals received in the second frequency band to the first frequency band and relay the converted signals.

[0014] As a wireless repeater, the relay devices 121 and 122 only amplify and convert the frequency of the communication between the terminal device 101 and the base station device 151, but also have a communication function for accepting control by the terminal device 101. In the present embodiment, the relay devices 121 and 122 are assumed to have a function as a wireless repeater, but the following discussion may be applied as necessary to a case where the relay devices 121 and 122 are configured to perform regenerative relay. As shown in FIG. 1, for example, the relay devices 121 and 122 have a communication function unit 131, which is a communication function for accepting control by the terminal device 101, and a relay function unit 132. The communication function unit 131 has a function for performing Sidelink communication in the 3GPP cellular communication standard with the terminal device 101, for example. This is an example, and the communication function unit 131 may be configured to communicate with the terminal device 101 by a communication function such as a wireless local area network (LAN) or Bluetooth (registered trademark). The terminal device 101 discovers the relay devices 121 and 122 with which it communicates via its communication function unit 131 using, for example, a side link communication function, and connects to the relay devices 121 and 122 through communication with the communication function unit 131 .

[0015] The relay function unit 132 has a wireless repeater function of amplifying and frequency converting a signal received from the terminal device 101 or the base station device 151, and outputting the amplified and frequency converted signal. The relay function unit 132 may operate in a frequency band different from that of the communication function unit 131. For example, the terminal device 101 may be configured to perform communication for controlling the relay devices 121 and 122 in a relatively low predetermined frequency band, and to perform communication with the base station device 151 via the relay devices 121 and 122 in a high frequency band such as the THz band or the millimeter wave band. This is just an example, and the communication function unit 131 may also use a frequency band used by the relay function unit 132, such as the THz band or the millimeter wave band. The communication function unit 131 and the relay function unit 132 are configured to operate in a frequency band corresponding to the operation of the terminal device 101. The terminal device 101 performs only control communication with the relay devices 121 and 122. In addition, by using relay devices 121 and 122 that are located at a short distance from the terminal device 101, the terminal device 101 does not need to transmit signals to the base station device 151 at high power, thereby reducing power consumption.

[0016] In the following, assuming that such a system configuration is used, various information to be transmitted and received between the terminal device 101, relay devices 121 and 122, and base station device 151 in this embodiment, and various processes to be executed will be described.

[0017] (Obtaining capability information about the wireless repeater part of a relay device) As described above, the terminal device 101 can execute control communication to control the relay devices 121 and 122. At that time, it is necessary for the terminal device 101 to recognize the capabilities of the relay devices 121 and 122. In particular, it is important for the terminal device 101 to recognize the relay communication function of the relay function unit 132 for communication with the base station device 151. In this embodiment, in consideration of such circumstances, the relay devices 121 and 122 use the communication function unit 131 to notify the terminal device 101 of capability information regarding the relay function unit 132. For example, the relay devices 121 and 122 transmit, as capability information, information indicating whether or not they have the relay function unit 132 to the terminal device 101. In addition, the relay devices 121 and 122 may transmit, as capability information, information indicating whether or not the relay function unit 132 can function as a virtual antenna of the terminal device 101 to the terminal device 101. By acquiring this information, the terminal device 101 becomes able to search for a relay device that can be used as a virtual antenna.

[0018] Furthermore, the relay devices 121 and 122 may notify the terminal device 101 of, for example, information indicating a frequency band available on the terminal device 101 side as capability information. That is, the relay devices 121 and 122 may notify the terminal device 101 of information on a first frequency band (for example, THz band) to which a radio signal transmitted from the base station device 151 is converted when relaying the radio signal to the terminal device 101 as a wireless repeater. The terminal device 101 may determine that the relay devices 121 and 122 are usable as virtual antennas, for example, on the condition that a frequency band available to the terminal device 101 matches a frequency band available to the relay devices 121 and 122. Furthermore, the relay devices 121 and 122 may notify the terminal device 101 of, for example, information indicating a second frequency band (for example, millimeter wave band) available for transmitting and receiving signals to and from the base station device 151 as capability information. The terminal device 101 may determine that the relay devices 121 and 122 can be used as virtual antennas, on the condition that the frequency bands available to the base station device 151 match the frequency bands available to the relay devices 121 and 122 on the base station device 151 side. These frequency bands may be notified to the terminal device 101 as a list of frequency bands available to the relay function unit 132, for example. The terminal device 101 can specify the frequency bands to be used in the communication performed by the terminal device 101 using the relay devices 121 and 122 by acquiring information on the frequency bands supported by the relay function units 132 in the relay devices 121 and 122. The relay devices 121 and 122 may notify the terminal device 101 of at least one of the above-mentioned first frequency band and second frequency band. In other words, the relay devices 121 and 122 do not necessarily have to notify the terminal device 101 of information on both the first frequency band and the second frequency band, but may notify the terminal device 101 of only information on either the first frequency band or the second frequency band.

[0019] The relay devices 121 and 122 may also notify the terminal device 101 of the number and configuration of physical antennas available in the relay function unit 132 as capability information. The information on the number of antennas may include, for example, information on the number of antennas available on the terminal device 101 side and the number of antennas available on the base station device 151 side. The information on the number of antennas may also include, for example, information indicating the number of antennas corresponding to each frequency band available on the relay devices 121 and 122. The information on the antenna configuration may include information on the positional relationship in which the antennas are arranged. The information on the antenna configuration may also include information on the number of streams that can be transmitted and received between the base station device 151 and the relay devices 121 and 122. Based on this information, the terminal device 101 may transmit multiple streams to the relay devices 121 and 122 using, for example, polarized waves or multiple frequency bands. The relay devices 121 and 122 may separate the multiple streams by polarized waves or frequency bands, and transmit these multiple streams in parallel using multiple antennas (and multiple frequency bands as necessary) on the base station device 151 side. In this way, the terminal device 101 can determine in what form communication can be performed via the relay devices 121 and 122 based on information on the number and configuration of antennas.

[0020] FIG. 2 shows an example of a process flow when the capability information of the relay devices 121 and 122 is provided to the terminal device 101. For example, the terminal device 101 transmits a message inquiring about capability information to each of the relay devices 121 and 122 (S201), and each of the relay devices 121 and 122 provides its own capability information to the terminal device 101 (S202). The terminal device 101 may transmit an inquiry message including information indicating whether or not the terminal device 101 is a terminal device that can use a virtual antenna. Then, when the terminal device 101 is capable of using a virtual antenna, the relay devices 121 and 122 may notify the terminal device 101 of information indicating whether or not the terminal device 101 has a function as a virtual antenna. The terminal device 101 may transmit an inquiry message including information about a frequency band (for example, a THz band) that can be used between the terminal device 101 and the relay device that functions as a virtual antenna. The terminal device 101 may transmit an inquiry message including information about a frequency band that the base station device 151 uses in communication. In these cases, the relay devices 121 and 122 may notify the terminal device 101 of information on a frequency band that can be used by the relay devices themselves as capability information, or may notify information indicating whether a frequency band included in an inquiry message is usable. The terminal device 101 may also transmit an inquiry message including information on the number and configuration of antennas that the relay devices 121 and 122 have. As described above, the relay devices 121 and 122 notify the terminal device 101 of information on the number and configuration of antennas that the relay devices have as capability information.

[0021] The terminal device 101 may obtain capability information on the wireless repeater part (relay function unit 132) from the relay devices 121 and 122, for example, by using a provision for sidelink communication in the 3GPP standard. In this case, the communication function units 131 of the relay devices 121 and 122 are configured to operate according to the provision for sidelink communication. In this case, for example, the capability information for sidelink communication can be used. In the sidelink communication, the terminal device transmits a UECapabilityEnquirySidelink message inquiring about obtaining capability information of another terminal device, and the other terminal device transmits a UECapabilityinformationSidelink message including capability information of the terminal device itself. For example, in the above-mentioned S201, the terminal device 101 transmits a first message obtained by extending the UECapabilityEnquirySidelink message to the relay devices 121 and 122. Then, when the communication function unit 131 of the relay devices 121 and 122 receives the message with the extended UECapabilityEnquirySidelink message, in the above-mentioned S202, it can transmit capability information regarding the wireless repeater part (relay function unit 132) to the terminal device 101 using the message with the extended UECapabilityinformationSidelink message.

[0022] The terminal device 101 may transmit, to the relay devices 121 and 122, information indicating an inquiry about capability information regarding the wireless repeater part in a message that is an extension of the UECapabilityEnquirySidelink message. This message may also include information inquiring about whether the relay devices 121 and 122 have a function as a wireless repeater (whether they can operate as a virtual antenna). The conventional UECapabilityEnquirySidelink message includes a frequencyBandListFilterSidelink that inquires about a frequency band corresponding to sidelink communication and a combination of frequency bands that can be combined and used in sidelink communication. This information includes only information about frequency bands for sidelink, and does not include information unrelated to sidelink communication, such as wireless repeaters. For this reason, in this embodiment, this information may be extended to make it possible to inquire about information about a frequency band that can be used regarding the wireless repeater part. The terminal device 101 may transmit, to the relay devices 121 and 122, a ue-CapabilityInformationSidelink that includes capability information of the terminal device, as in the conventional UECapabilityEnquirySidelink message. This is just an example, and capability information may not be transmitted from the terminal device 101 to the relay devices 121 and 122. In addition, the UECapabilityEnquirySidelink message may be extended to include information inquiring about the number and configuration of antennas of the wireless repeater parts of the relay devices 121 and 122.

[0023] The relay devices 121 and 122 notify the terminal device 101 of, for example, information indicating whether the relay devices 121 and 122 have a function as a wireless repeater, using a message that is an extension of the UECapabilityinformationSidelink message. The relay devices 121 and 122 can also notify the terminal device 101 of the supported frequency bands (and combinations of supported frequency bands) of the wireless repeater part, using information similar to the conventional supportedBandCombinationListSidelink and supportedBandListSidelink. The relay devices 121 and 122 also notify the terminal device 101 of the number and configuration of antennas of the wireless repeater part.

[0024] The relay devices 121 and 122 may notify the terminal device 101 of the above-mentioned capability information without following the rules of sidelink communication. For example, the capability information may be notified using a profile of Bluetooth (registered trademark). That is, the communication function units 131 of the terminal device 101 and the relay devices 121 and 122 may be configured to perform Bluetooth communication. Then, in the above-mentioned S202, the relay devices 121 and 122 may notify the terminal device 101 of information such as whether or not they have a function as a virtual antenna, a supported frequency band, the number and configuration of antennas, etc., using Generic Attribute Profile (GATT). The terminal device 101 may also notify the relay devices 121 and 122 of information about its own device using GATT. The communication function units 131 of the terminal device 101 and the relay devices 121 and 122 may transmit and receive capability information using wireless LAN.

[0025] The terminal device 101 identifies the relay devices 121 and 122 that can operate as virtual antennas, for example, from the acquired capability information of the relay devices 121 and 122. The terminal device 101 recognizes the configuration of the virtual antenna based on the frequency bands and the number and configuration of antennas that the relay devices 121 and 122 can use on the base station device 151 side, and can communicate with the base station device 151 using the configuration. The relay devices 121 and 122 may transmit their own capability information without receiving an inquiry message from the terminal device 101. For example, the relay devices 121 and 122 may voluntarily transmit their own capability information in response to, for example, being turned on or receiving a user operation to turn on the function as a virtual antenna. The terminal device 101 can recognize the presence of a device having a function as a virtual antenna in the vicinity by detecting such capability information.

[0026] (Update of terminal device capability information) As described above, the terminal device 101 can communicate with the base station device 151 by using the relay devices 121 and 122 as virtual antennas. The terminal device 101 notifies the base station device 151 of capability information such as the number of antennas, assuming the existence of such virtual antennas. For example, when the relay devices 121 and 122 each have two antennas on the base station device 151 side, the terminal device 101 can be said to have four antennas virtually because the two relay devices each have two antennas. Therefore, in such a case, the terminal device 101 can notify the base station device 151 of the fact that it has four antennas as capability information. On the other hand, in such an environment, for example, when one of the relay devices 121 and 122 is powered off or when a connection with a new relay device is established, the number of virtual antennas in the terminal device 101 can change.

[0027] Also, for example, when transmitting channel state information (CSI) to the base station device 151, the terminal device 101 can compress the CSI using artificial intelligence (AI) / machine learning (ML). For example, a first trained model for acquiring compressed CSI that can obtain a compression ratio determined by a predetermined standard, such as the lowest compression ratio or a compression ratio below a reference value, by ML using the uncompressed CSI as an input, and a second trained model for acquiring uncompressed CSI by ML using the compressed CSI as an input are acquired. At this time, the first trained model is held in the terminal device 101, and the second trained model is held in the base station device 151. For example, the terminal device 101 can acquire CSI by channel estimation in its own device, perform ML based on the information, generate a first trained model and a second trained model, and notify the base station device 151 of the second trained model. This second trained model is provided from the terminal device 101 to the base station device 151 as, for example, capability information. The capability information may indicate only whether or not the first learned model and the second learned model can compress and restore the CSI, and the second learned model may be notified to the base station device 151 separately from the capability information. As a result, when the terminal device 101 acquires CSI by channel estimation, the terminal device 101 compresses the CSI using the first learned model and transmits it to the base station device 151, and the base station device 151 inputs the received compressed CSI to the second learned model to obtain the result of channel estimation in the terminal device 101. On the other hand, for example, when the communication environment between the terminal device 101 and the base station device 151 changes significantly, it is assumed that the learned model will no longer be suitable for the communication environment. In this case, the terminal device 101 may update the second learned model notified to the base station device 151 as capability information.

[0028] Furthermore, the terminal device 101 can control the beam to be used in communication between the terminal device 101 and the base station device 151 by AI / ML. For example, the terminal device 101 and the base station device 151 measure wireless quality using only a part of many available beams, and perform ML to select an optimal beam from all available beams using the measurement results as input, thereby generating a trained model. In one example, the base station device 151 transmits a signal for measurement using all available beams, and the terminal device 101 selects an optimal beam from the measurement results of the signal, while using the measurement results of signals transmitted using some beams as input, a trained model can be generated by ML using the selected optimal beam as teacher data. At this time, the terminal device 101 can notify the base station device 151 as capability information that beam selection can be performed using the trained model. In this case, too, if the communication environment between the terminal device 101 and the base station device 151 changes significantly, it is assumed that the trained model will no longer be suitable for that communication environment. In this case, even though the terminal device 101 has notified the base station device 151 that it is capable of performing beam selection using a learned model as capability information, it is expected that the terminal device 101 will be unable to perform this.

[0029] In this way, it is assumed that the capability information of the terminal device 101 changes dynamically when a virtual antenna is used or when AI / ML is used. In contrast, conventionally, the terminal device 101 cannot provide its own capability information to the base station device 151 unless there is an inquiry from the base station device 151. For this reason, the base station device 151 may end up communicating with the terminal device 101 according to inaccurate capability information. Here, the base station device 151 acquires the capability information of the terminal device 101 when establishing a connection with the terminal device 101. For this reason, the terminal device 101 may disconnect the connection and execute a reconnection process every time the capability information changes. However, in this case, disconnection and reconnection are repeated every time the configuration of the virtual antenna or the communication situation in the terminal device 101 changes, and signaling overhead may increase significantly.

[0030] In this embodiment, in consideration of such circumstances, the terminal device 101 is enabled to spontaneously transmit capability information to the base station device 151 while maintaining a connection with the base station device 151. An example of the flow of this process is shown in FIG. 3(A) and FIG. 3(B). For example, when the terminal device 101 detects the need to change the capability information (S301), the terminal device 101 decides to transmit the capability information to the base station device 151 (S302). Then, the terminal device 101 spontaneously transmits the capability information to the base station device 151, for example. The terminal device 101 transmits UECapabilityInformation to the base station device 151 without receiving an inquiry message from the base station device 151. Also, the terminal device 101 may request, for example, the base station device 151 to transmit an inquiry message (S311). That is, the terminal device 101 transmits a message requesting transmission of a UECapabilityEnquiry message to the base station device 151. When the terminal device 101 receives UECapabilityEnquiry transmitted from the base station device 151 in response to this request message (S312), it transmits UECapabilityInformation to the base station device 151 in response to it (S313). In this way, in a state where the terminal device 101 has not received an inquiry about capability information from the base station device 151, it transmits a signal for transmitting capability information to the base station device 151. Then, the terminal device 101 notifies the base station device 151 of the changed capability information using this signal, so that the base station device 151 can control the communication of the terminal device 101 using accurate capability information.

[0031] A message for the terminal device 101 to transmit capability information or a capability information inquiry message to the base station device 151 is transmitted using, for example, a radio resource control (RRC) message, a physical uplink control channel (PUCCH), or a medium access control control element (MAC CE). When the terminal device 101 spontaneously transmits capability information, the capability information may include all of the changed capability information of the terminal device 101 to the base station device 151, or may include only the changed part of the capability information to the base station device 151. In addition, in a message for causing the base station device 151 to transmit a capability information inquiry message, the terminal device 101 may transmit only a request to transmit an inquiry message, or may transmit, for example, information indicating which item of the capability information is to be changed.

[0032] The capability information transmitted from the terminal device 101 to the base station device 151 may include, for example, MIMO (Multiple Input Multiple Output) related information and information on a corresponding frequency band. The MIMO related information may include, for example, setting information (SRSConfig) of a sounding reference signal (SRS), beam setting information (SpatialrelationInfo), and the number of layers (maxNumberMIMOLayersPDSCH, maxNumberMIMO-LayersCBPUSCH) of MIMO for each of the downlink and uplink. As described above, information required to execute the function, such as information on a model by AI / ML, may be included in the capability information.

[0033] For example, the terminal device 101 may determine that the capability information needs to be changed in response to a loss of connection with a relay device used as a virtual antenna, or in the case of a new connection with a relay device used as a virtual antenna. In addition, the terminal device 101 may determine whether the original CSI is restored as a result of inputting the compressed CSI obtained by inputting the CSI into a first trained model for compression into a second trained model for decompression, and may determine that the capability information needs to be changed (re-learning of the model) if the original CSI is not restored accurately (if the error exceeds a predetermined value). In addition, the terminal device 101 may input the measurement results of only a portion of the available beams into the trained model and determine whether the beam identified as the beam to be used is the optimal beam among all the available beams. That is, the terminal device 101 may, for example, periodically perform measurements on all the available beams, and determine whether the beam to be used determined according to the results of the measurements matches the beam identified using the trained model. Then, when those beams do not match, the terminal device 101 may determine that a change in capability information (re-learning of the model) is necessary. In one example, when re-learning of the model is necessary, the terminal device 101 may transmit a transmission request for capability information or a capability information inquiry message to the base station device 151 in response to completion of re-learning. In this way, since a re-learned model exists at the time when the message is transmitted, communication using the re-learned model can be performed in a short time.

[0034] In addition, the terminal device 101 may transmit a request to transmit capability information or a capability information inquiry message to the base station device 151 in response to determining that re-learning of the model is necessary. In this case, the base station device 151 can immediately stop using a trained model for decompressing CSI that is no longer suitable for the communication situation, for example. Note that until the terminal device 101 updates the trained model and provides it to the base station device 151, and until the base station device 151 receives the updated trained model, the CSI can be provided from the terminal device 101 to the base station device 151 in a conventional procedure. This makes it possible to prevent communication control based on inaccurate CSI caused by using an inappropriate trained model. In addition, the base station device 151 can transmit a measurement signal with all available beams to cause the terminal device 101 to perform re-learning, for example, in order to update a trained model for beam control that is no longer suitable for the communication situation.

[0035] (Reporting wireless quality to terminal devices by relay devices) When communication between the terminal device 101 and the base station device 151 is performed using the relay devices 121 and 122 as described above, both the wireless quality associated with the first transmission path (for example, THz band) between the terminal device 101 and the relay devices 121 and 122 and the wireless quality associated with the second transmission path (for example, millimeter wave band) between the relay devices 121 and 122 and the base station device 151 affect the communication quality of the communication between the terminal device 101 and the base station device 151. For example, it is assumed that a wireless signal transmitted from the base station device 151 is received at the relay devices 121 and 122 with low power, and noise caused by the relay devices 121 and 122 is added to the wireless signal, resulting in a low signal-to-noise ratio (SNR). When the wireless signal with a low SNR is amplified, not only the signal component but also the noise component is greatly amplified, so that the SNR of the wireless signal remains low even if the reception power of the wireless signal at the terminal device 101 is sufficient. Similarly, when the SNR of a wireless signal transmitted from the terminal device 101 and received at the relay devices 121 and 122 is low, even if the received power of the wireless signal transmitted from the relay devices 121 and 122 and received at the base station device 151 is sufficient, the SNR of the wireless signal remains low. That is, when the power of the signal arriving at the relay devices 121 and 122 is low, the SNR becomes low due to noise caused by the relay devices 121 and 122, and the wireless signal is amplified, even if the received power of the wireless signal at the terminal device 101 and the base station device 151 is sufficient, the SNR of the wireless signal may remain low.

[0036] In such a case, it may be assumed that the communication between the terminal device 101 and the base station device 151 cannot normally transmit and receive radio signals even though the radio quality (received power) in the terminal device 101 appears to be good. In response to this, the terminal device 101 can ensure a sufficiently high communication quality of the communication between the terminal device 101 and the base station device 151 by using, for example, a relay device in which the radio quality in both the first transmission path and the second transmission path can achieve a predetermined quality level as a virtual antenna. On the other hand, the terminal device 101 and the base station device 151 can recognize the communication quality of the communication via the entire transmission path between the terminal device 101 and the base station device 151 using an existing method such as channel estimation, but cannot recognize the communication quality that distinguishes between the first transmission path and the second transmission path. For this reason, the terminal device 101 cannot select an appropriate relay device for ensuring a sufficiently high communication quality of the communication between the terminal device 101 and the base station device 151.

[0037] In this embodiment, in consideration of such circumstances, the relay devices 121 and 122 specify the wireless quality of the first transmission path and the wireless quality of the second transmission path in the relay function unit 132 and notify the terminal device 101 of the result of the specification. For example, the relay function units 132 of the relay devices 121 and 122 measure a predetermined signal transmitted from the terminal device 101 and the base station device 151 to measure the wireless quality of the first transmission path and the wireless quality of the second transmission path, respectively. Then, the relay function unit 132 provides the result of the measurement to the communication function unit 131, and the communication function unit 131 notifies the terminal device 101 of the measurement value of the provided wireless quality. Here, the predetermined signal may be, for example, a reference signal or a synchronization signal generated using a known sequence, and the wireless quality may be, for example, the received power of the signal or a signal-to-noise and interference ratio (SINR). The relay function unit 132 may measure the wireless quality by, for example, correlation detection using a known sequence used to generate the predetermined signal. The relay function unit 132 may measure the reception power of the wireless signal using, for example, a power detector connected to antennas on the terminal device 101 side and the base station device 151 side. The power detector may be arranged so as to be accessible by the communication function unit 131. In this case, the relay function unit 132 may not have a correlation detection function or a function of providing information to the communication function unit 131. That is, the relay function unit 132 may be configured only with a function as a wireless repeater such as amplification of a received signal and frequency conversion. At least one of the wireless qualities of the first transmission path and the second transmission path may be measured and reported to the terminal device 101. That is, only the wireless quality of the first transmission path may be measured and reported, only the wireless quality of the second transmission path may be measured and reported, or both may be measured and reported.

[0038] In addition, the relay devices 121 and 122 may, for example, periodically measure the wireless quality of the first transmission path and the second transmission path, respectively, or may perform the measurement in response to receiving an instruction from the terminal device 101. In one example, the base station device 151 may transmit a predetermined notification to the terminal device 101 when the received power of the signal from the terminal device 101 is sufficient but the quality such as the SNR is insufficient. Then, when the terminal device 101 receives the predetermined notification, it may transmit an instruction signal to the relay devices 121 and 122 to perform the measurement. Similarly, the terminal device 101 may transmit an instruction signal to the relay devices 121 and 122 to perform the measurement when the received power of the signal from the base station device 151 is sufficient but the quality such as the SNR is insufficient.

[0039] 4 shows an example of the flow of this process. In this process, the relay devices 121 and 122 measure radio quality such as the received power of a downlink radio signal transmitted from the base station device 151 (S401, S402), and also measure radio quality such as the received power of an uplink radio signal transmitted from the terminal device 101 (S403, S404). Note that the relay devices 121 and 122 are connected to the terminal device 101 and function as virtual antennas, and a signal transmitted from the base station device 151 is relayed to the terminal device 101, and a signal transmitted from the terminal device 101 is relayed to the base station device 151. The relay devices 121 and 122 notify the terminal device 101 of at least one of the measurement results of S402 and S404 (S405). Note that the notification of S405 can be performed using, for example, sidelink communication, Bluetooth, wireless LAN, or the like. In addition, when sidelink communication is used, the notification of S405 may be performed using a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH). In addition, the relay devices 121 and 122 may perform measurement and reporting periodically, or may perform measurement and reporting non-periodically according to a measurement instruction (S406) from the terminal device 101. In addition, the terminal device 101 may instruct the communication function unit 131 of the relay devices 121 and 122 to perform reporting on the condition that the measurement result satisfies a predetermined condition. In this way, the terminal device 101 can acquire the measurement result of the wireless quality of the first transmission path between the relay devices 121 and 122 and the terminal device 101 and the measurement result of the wireless quality of the second transmission path between the relay devices 121 and 122 and the base station device 151 in the relay devices 121 and 122.

[0040] When the terminal device 101 receives the measurement result of the wireless quality in the relay devices 121 and 122, the terminal device 101 transmits the measurement result to the base station device 151, for example. The base station device 151 may execute transmission power control or the like based on the measurement result. For example, when the wireless quality (for example, the received power in the relay devices 121 and 122) regarding the second transmission path is low, the base station device 151 performs control to increase the transmission power of the downlink signal. Also, when the measurement result of the received wireless quality indicates that the wireless quality regarding the first transmission path is low (for example, lower than a predetermined value), the terminal device 101 may perform control to increase the transmission power of the uplink signal. Also, when the terminal device 101 uses a relay device having insufficient wireless quality (wireless quality lower than a predetermined value) regarding at least one of the first transmission path and the second transmission path as a virtual antenna, the terminal device 101 may stop using the relay device. Also, the terminal device 101 may switch the relay device to be used. The terminal device 101 may instruct relay devices not used as virtual antennas to measure and report wireless quality. This allows the terminal device 101 to select a relay device with good wireless quality from among unused relay devices and use it as a new virtual antenna.

[0041] (Frequency conversion in repeater devices) As described above, the terminal device 101 multiplexes and transmits signals to the relay devices 121 and 122 using polarization or multiple frequency channels (for example, THz band), and the relay devices 121 and 122 convert the signals to signals of one frequency channel and relay them to the base station device 151. At this time, if the frequency channel after conversion in the relay devices 121 and 122 is fixedly given, many terminal devices using virtual antennas will use that frequency channel, and it will be difficult to secure sufficient resources for that frequency channel. Note that the "frequency channel" here may be set multiple times for one frequency band, or may be set only one for one frequency band. In other words, the frequency channel may be a partial band of one frequency band, or may be the entirety of one frequency band.

[0042] For this reason, in this embodiment, the relay devices 121 and 122 are configured to be able to use multiple different frequency channels included in a frequency band that can be used to relay a wireless signal to the base station device 151. Then, the relay devices 121 and 122 set the frequency channel to be used when relaying a signal to the base station device 151 according to an instruction from the terminal device 101. This makes it possible to prevent communications of many terminal devices using the relay devices from concentrating on a specific frequency channel, and also to improve the flexibility of frequency resource allocation.

[0043] 5 shows an example of the configuration of the relay devices 121 and 122 according to the present embodiment. For example, the terminal device 101 transmits radio signals including separate data on frequency channel A and frequency channel B. Then, when the relay devices 121 and 122 receive the radio signals, they separate the radio signals using a band pass filter (BPF) 502 that passes only the band of frequency channel A and a BPF that passes only the band of frequency channel B. Then, the relay devices 121 and 122 frequency convert the frequency of the radio signals to frequency C or frequency D using, for example, a waveform output by an oscillator 503. The frequency-converted radio signals are supplied to a switch 504 so as to be input to either a BPF 505 for frequency C or a BPF 506 for frequency D. For example, when a radio signal is to be output at frequency C, the switch 504 switches the output destination so that the radio signal is input to the BPF 505 and the radio signal is not input to the BPF 506. Furthermore, switch 504 switches the output destination so that, for example, when a radio signal should be output at frequency D, the radio signal is input to BPF 506 and the radio signal is not input to BPF 505. Then, when the frequency of the radio signal to be relayed is frequency C, the radio signal that has passed through BPF 505 is amplified and relayed (output from the antenna), and when the frequency of the radio signal to be relayed is frequency D, the radio signal that has passed through BPF 506 is amplified and relayed (output from the antenna).

[0044] In addition, while FIG. 5 shows an example in which two frequency bands (frequency C and frequency D) can be used to relay a wireless signal to the base station device 151, the relay devices 121 and 122 may be configured to be able to use three or more frequency bands. In addition, while an example in which the wireless signals transmitted from the terminal device 101 to the relay devices 121 and 122 are frequency-multiplexed is shown, the signals may be multiplexed using polarization or time, for example. In this case, the relay devices 121 and 122 may perform conversion processing of the wireless signals so that the signals are separated from each other using different polarizations or different times, and are transmitted at the same frequency and time using multiple antennas. However, in either case, when the relay function unit 132 operates as a wireless repeater, processing such as demodulation and decoding of signals, and re-encoding and re-modulation of signals does not need to be performed.

[0045] The relay devices 121 and 122 receive instruction information from the terminal device 101 using the communication function unit 131, for example. The instruction information includes the changed frequency. When the communication function unit 131 receives the instruction information from the terminal device 101, it supplies the instruction content to the control unit 501. Then, in the relay devices 121 and 122, the control unit 501 controls the frequency of the oscillator 503 and the switch 504 so that a radio signal of the instructed frequency is output. That is, the control unit 501 controls the transmission frequency of the oscillator 503, and further sets the output destination of the switch 504 so that the radio signal after the frequency change is input to an appropriate BPF. The relay devices 121 and 122 notify the terminal device 101 of the available frequency band (frequency channel) as capability information, as described above. The terminal device 101 transmits information on the frequency band indicated as available by the capability information to the base station device 151 as capability information of the own device. Then, the base station device 151 selects one of the available frequency bands indicated as the capability information, and allocates frequency resources included in the selected frequency band to the terminal device 101. The terminal device 101 instructs the relay devices 121 and 122 to use the allocated frequency band. Then, the control units 501 of the relay devices 121 and 122 convert the radio signal arriving from the terminal device 101 into a radio signal of that frequency band and relay it.

[0046] 6 shows an example of the flow of frequency setting processing of the relay devices 121 and 122. In this processing, first, the relay devices 121 and 122 transmit capability information including frequency bands available for relaying wireless signals to the base station device 151 to the terminal device 101 (S601). Then, the terminal device 101 notifies the base station device 151 (for example, via the relay devices 121 and 122, or directly without via the relay devices 121 and 122) of capability information indicating the frequency bands available to the relay devices 121 and 122 as the frequency bands available to the terminal device 101 (S602). Then, the base station device 151 selects one of the frequency bands indicated by the capability information, allocates resources for uplink communication in that frequency band, and notifies the terminal device 101 of information indicating the allocated resources (for example, via the relay devices 121 and 122, or directly without via the relay devices 121 and 122) (S603). The base station device 151 may notify the terminal device 101 of a combination of information on a frequency band to be used and information indicating which resource in the frequency band is to be allocated. If the information designating a frequency resource specifies a frequency band including the frequency resource, the information on the frequency band may not be notified to the terminal device 101. The terminal device 101 transmits an instruction to the relay devices 121 and 122 to relay an uplink signal to the base station device 151 using a frequency band corresponding to the allocated frequency resource (S604). Then, in accordance with the instruction, the relay devices 121 and 122 control, for example, the oscillator 503 and the switch 504 to perform settings to relay the uplink signal to the base station device 151 using the designated frequency band (S605).

[0047] The base station device 151 may notify the terminal device 101 of information indicating which frequency band is to be used in which time slot (time). In this case, the terminal device 101 may similarly notify the relay devices 121 and 122 of information associating the time slot with the frequency band to be used, and the control units 501 of the relay devices 121 and 122 may execute a control process to change the frequency band to be used over time according to the information. This makes it possible to switch the frequency band to be used at an appropriate timing, and it becomes possible to use a large number of frequency bands more flexibly. In addition, information associating a plurality of time slots (times) with the corresponding frequency bands to be used may be notified to the relay devices 121 and 122. The relay devices 121 and 122 perform control to use the corresponding frequency band in each of the plurality of time slots. In this way, by notifying information specifying the time change of the frequency band to be used, it is possible to reduce the number of times of transmission of the instruction signal, and it becomes possible to switch the frequency band to be used frequently and flexibly. The terminal device 101 may transmit the instruction of the frequency band to be used to the multiple relay devices 121 and 122 individually, or may transmit the instruction to all of them at once by multicast.

[0048] Thereafter, the terminal device 101 transmits an uplink signal using a time and frequency range in the frequency band before conversion by the relay devices 121 and 122, which corresponds to the resource allocated in S603 (e.g., a specific time and frequency range in the frequency band to be used indicated by the resource block). For example, if the lower end of the frequency band (e.g., frequency C or frequency D in FIG. 5) used when relaying a wireless signal from the relay devices 121 and 122 to the base station device 151 is f2, the lower end of the allocated frequency resource is f2+Δ, and the lower end of the frequency band (e.g., frequency A in FIG. 5) when transmitting a wireless signal from the terminal device 101 to the relay devices 121 and 122 is f0, the terminal device 101 transmits an uplink signal in a frequency resource whose lower end is f0+Δ. In addition, as shown in Fig. 5, when transmitting radio signals using multiple frequency bands to the relay devices 121 and 122, for example, when the lower ends of two frequency bands (for example, frequency A and frequency C in Fig. 5) are f0 and f1, respectively, the terminal device 101 transmits uplink signals in frequency resources whose lower ends are f0+Δ and f1+Δ. In this way, for example, the base station device 151 can flexibly allocate radio resources, and it is possible to avoid congestion in only a specific frequency band.

[0049] (Identification of intermediate devices with analogue functionality only) In the above example, the terminal device 101 uses the side link communication function or the like to discover and connect to the relay devices 121 and 122 having the communication function unit 131, and uses the connected relay devices 121 and 122 as virtual antennas. The terminal device 101 determines its own device's (virtual) capabilities, such as the number of layers of MIMO, by recognizing the relay device that can be used as a virtual antenna, so that it is necessary to recognize the relay device when using a virtual antenna. On the other hand, if the relay devices 121 and 122 have only the relay function unit 132 and do not have the communication function unit 131, it is assumed that the terminal device 101 cannot discover the relay devices 121 and 122 because it cannot use the side link communication function or the like.

[0050] In this embodiment, in consideration of such circumstances, in order to discover a relay device having only the relay function unit 132, the terminal device 101 transmits at least one of a signal in a first frequency band (for example, THz band) used when communicating with the base station device 151 using a virtual antenna and a signal in a second frequency band (for example, millimeter wave band) converted by the relay device, and detects radio waves in the frequency band after frequency conversion (performed when a relay device exists). That is, when a relay device exists nearby, a radio signal transmitted by the terminal device 101 is frequency converted by the relay device and output, so that when the terminal device 101 can detect the radio signal after frequency conversion, it can determine that a relay device exists nearby. That is, when the terminal device 101 detects a signal in the second frequency band after transmitting a signal in the first frequency band, or when it detects a signal in the first frequency band after transmitting a signal in the second frequency band, it can determine that a relay device exists nearby.

[0051] The terminal device 101 may periodically transmit at least one of a signal in the first frequency band and a signal in the second frequency band, and perform a process of detecting a signal in the converted frequency band. However, this is not limited to this, and the terminal device 101 may transmit a signal and perform a process of detection when a predetermined event is detected. For example, the terminal device 101 may transmit a signal and perform a process of detection when a user operation on the terminal device 101 instructs the start of detection. For example, the relay device is a device whose existence can be recognized by a user, such as a wireless device held by a user, such as a smart watch, and it is assumed that the user turns on the switch of the device to instruct the start of detection of the device.

[0052] Here, the relay device has a constant amplification factor, for example. At this time, the terminal device 101 transmits a signal with sufficiently weak power. This prevents a signal transmitted by the terminal device 101 in a first frequency band from strongly interfering with signals from other terminal devices in the base station device 151, even if the signal is amplified by the relay device and output in a second frequency band. Similarly, the terminal device 101 transmits a signal in the second frequency band with sufficiently weak power and detects a signal in the first frequency band. Note that THz band signals are subject to large distance attenuation, and even if they are amplified and output, the range of their radio waves is limited, so it is assumed that they will not interfere with other signals.

[0053] For example, frequency and time resources for searching for a relay device may be prepared in the form of a resource pool. For example, a resource that allows the terminal device 101 to transmit a search signal and a corresponding resource for the terminal device 101 to receive a signal that has been converted and relayed are set. For example, a THz band frequency and time resource are prepared as a first resource, and a millimeter wave band frequency and time resource corresponding to the first resource are prepared as a second resource. Furthermore, a millimeter wave band frequency and time resource are prepared as a third resource, and a THz band frequency and time resource corresponding to the third resource are prepared as a fourth resource. The terminal device 101 transmits a signal in the first resource or the third resource, and determines whether the frequency-converted signal is detected in the second resource or the fourth resource, thereby determining whether a relay device exists. For example, the first resource may be set in a period in which the base station device 151 does not transmit a millimeter wave band signal. For example, the first resource is set in a time slot to which an uplink resource is assigned. In addition, the second resource corresponding to the first resource may also be set in the same time slot. If a relay device is present, the signal transmitted in the first resource in the THz band is converted into a signal in the second resource in the millimeter wave band by the relay device and relayed. According to the above-mentioned setting, since the base station device 151 does not transmit a millimeter wave band signal, the terminal device 101 can measure the millimeter wave band signal relayed by the relay device under interference-free conditions. In addition, the above-mentioned third resource may also be set at a timing when the base station device 151 does not transmit a millimeter wave signal, that is, in a time slot assigned to the uplink. The terminal device 101 transmits a millimeter wave signal in the third resource in which the base station device 151 does not transmit a millimeter wave signal, and performs a detection process of the THz band signal in the fourth resource.According to the above-mentioned setting, since the base station device 151 does not transmit a millimeter wave band signal, the relay device does not relay the millimeter wave band signal, and the terminal device 101 can measure the millimeter wave band signal relayed by the relay device under interference-free conditions. Note that, although it is assumed that a THz band signal is transmitted between another terminal device and a corresponding relay device, due to the high frequency of the signal, the interference of the signal with the signal transmitted between the terminal device 101 and the relay device can be ignored.

[0054] In this manner, the terminal device 101 can recognize a relay device that does not have the communication function unit 131 and use the relay device as a virtual antenna. In the above example, the terminal device 101 transmits a signal for searching for a relay device during a period in which the base station device 151 does not transmit a millimeter wave signal, but the present invention is not limited to this. For example, the terminal device 101 may notify the base station device 151 that it searches for a relay device and receive a resource for searching from the base station device 151. In this case, the terminal device 101 may transmit a signal for searching while the base station device 151 is transmitting a signal in the millimeter wave band. However, the base station device 151 is prevented from transmitting a signal in the millimeter wave band wireless resource used by the relay device when relaying the signal, corresponding to the wireless resource in which the terminal device 101 transmits the millimeter wave band signal for searching and the THz band wireless resource in which the terminal device 101 transmits the signal for searching. This can prevent interference caused by a signal from the base station device 151 in the wireless resource for the terminal device 101 to search for a relay device. Also, for example, it is assumed that the relay device can relay wireless signals in a plurality of frequency bands as described above. Therefore, the terminal device 101 may execute a detection process of the signal in the plurality of frequency bands. That is, the terminal device 101 may execute a detection process of the relay device using a combination of a plurality of frequency bands. Note that since the terminal device 101 knows the signal transmitted by itself, it may detect the signal from the relay device by performing correlation detection using a waveform obtained by frequency converting the signal, or may detect the signal from the relay device by simply performing power detection in the resource after frequency conversion.

[0055] Furthermore, when multiple relay devices exist, the terminal device 101 may execute a detection process so as to detect each of the multiple relay devices. For example, the terminal device 101 may form multiple beams and execute a detection process for each beam to detect relay devices present in the direction in which the beam is directed, and may use other beams to detect relay devices present in other directions. That is, the terminal device 101 may execute a detection process for each beam to detect relay devices present in different directions by separating them by beam. Note that, by changing the beam to be used over time, it is possible to specify which beam the relay device was found for, but this is not limited to this. For example, the terminal device 101 may execute a detection process for relay devices by using multiple beams in parallel, using different sequences for each beam. That is, the terminal device 101 may specify which beam the relay device is present in, depending on which sequence of signals was detected. Also, for example, when all relay devices to be searched for perform the same frequency conversion, the terminal device 101 may execute a detection process for relay devices by using multiple beams in parallel, using different frequency resources for each beam. That is, the terminal device 101 can identify in which beam direction the relay device exists, depending on which frequency resource a signal is detected.

[0056] FIG. 7 shows an example of a process flow in which the terminal device 101 searches for an intermediate device that does not have the communication function unit 131. The terminal device 101 transmits a search signal in a first resource (or a third resource) periodically or in response to the occurrence of a predetermined event (S701). For example, after the intermediate device is turned on by a user operation, the intermediate device converts the frequency of the signal to a second resource (or a fourth resource when the intermediate device receives a search signal transmitted using the third resource) (S702), amplifies the signal, and then outputs the signal (S703). The terminal device 101 detects the intermediate device in response to receiving a wireless signal transmitted from the intermediate device in the second resource (S704). For example, the terminal device 101 determines whether the received signal is a signal that has been frequency-converted from a wireless signal transmitted by the terminal device itself, thereby determining whether the received signal is a signal that has been relayed by the intermediate device, and can determine whether the intermediate device exists according to the determination result. However, the present invention is not limited to this, and may determine that a relay device exists when a power equal to or higher than a predetermined level is detected in the second resource. Then, when the terminal device 101 determines that a relay device exists, the terminal device 101 communicates with the base station device 151 using the relay device as a virtual antenna.

[0057] In this way, when there is a relay device that does not have a communication function unit 131, the terminal device 101 can detect the relay device and use the relay device as a virtual antenna to communicate with the base station device 151.

[0058] (Device configuration) Next, a configuration example of the terminal device 101 and the relay devices 121 and 122 configured to execute the above-mentioned processing will be described. Since the functions that the terminal device 101 and the relay devices 121 and 122 should have are as described above, only the general configuration of the terminal device 101 and the relay devices 121 and 122 will be described below. Since the base station device 151 has roughly the same functions as conventional base station devices, it will not be described here. The detailed operation of the base station device 151 is as described above.

[0059] FIG. 8 shows an example of a hardware configuration of the communication function unit 131 and the control unit 501 of the terminal device 101 and the relay devices 121 and 122 according to this embodiment. In the following, the communication function unit 131 and the control unit 501 of the relay devices may be simply called a relay device. In one example, the terminal device 101 and the relay devices 121 and 122 include a processor 801, a ROM 802, a RAM 803, a storage device 804, and a communication circuit 805. The processor 801 is a computer including one or more processing circuits such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and executes the overall processing of the device and each of the above-mentioned processes by reading and executing a program stored in the ROM 802 or the storage device 804. The ROM 802 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the terminal device 101 and the relay devices 121 and 122. The RAM 803 functions as a workspace when the processor 801 executes a program, and is a random access memory that stores temporary information. The storage device 804 is, for example, a removable external storage device. The communication circuit 805 is, for example, a circuit for wireless communication of 5G or its successor standard. Although one communication circuit 805 is illustrated in FIG. 8, the terminal device 101 and the relay devices 121 and 122 may have multiple communication circuits. For example, the terminal device 101 and the relay devices 121 and 122 may have a wireless communication circuit for each of 5G and its successor standard, and a common antenna for these circuits, and may have a configuration capable of executing a sidelink communication function. The terminal device 101 and the relay devices 121 and 122 may have separate antennas suitable for each standard. The terminal device 101 may further have a communication circuit conforming to a wireless communication standard other than a cellular communication standard, such as wireless LAN or Bluetooth (registered trademark). Furthermore, the relay devices 121 and 122 may have a communication circuit for wireless LAN or Bluetooth in addition to or instead of the communication circuit for cellular communication.

[0060] Fig. 9 is a diagram showing an example of a functional configuration of the terminal device 101. The terminal device 101 has a first communication unit 901, a second communication unit 902, a virtual antenna control unit 903, and an AI / ML function unit. These functions can be implemented, for example, by the processor 801 executing a program stored in the ROM 802 or the storage device 804, or by the communication circuit 805. However, this is just one example, and the functions of Fig. 9 may be realized by other configurations. Also, the functions shown in Fig. 9 are just one example, and the various processes described above may be realized by other functional units.

[0061] The first communication unit 901 is, for example, a function unit for communicating with the communication function unit 131 of the relay devices 121 and 122. The first communication unit 901 has, for example, a side link communication function. The first communication unit 901 may have a Bluetooth communication function or a wireless LAN communication function instead of or in addition to the side link communication function. Control communication between the relay devices 121 and 122 is performed using the first communication unit 901. The second communication unit 902 communicates with the base station device 151. Communication of user data and communication of control data between the base station device 151 are performed via the second communication unit 902. When the second communication unit 902 does not use a virtual antenna, the second communication unit 902 may directly transmit, for example, a millimeter wave band signal to the base station device 151. When the second communication unit 902 uses a virtual antenna, the second communication unit 902 may transmit, for example, a THz band signal. The THz band signal is converted into a millimeter wave band signal via the relay devices 121 and 122 and transferred to the base station device 151. The second communication unit 902 also directly receives the millimeter wave band signal transmitted from the base station device 151, or receives the THz band signal converted by the relay devices 121 and 122.

[0062] The virtual antenna control unit 903 executes various controls to be performed when the relay devices 121 and 122 are used as virtual antennas and when they are used as virtual antennas. For example, the virtual antenna control unit 903 detects a relay device using the first communication unit 901 or the second communication unit 902, and executes a connection process with the relay device to use the relay device as a virtual antenna. In addition, the virtual antenna control unit 903 executes, for example, the above-mentioned various control communications associated with the use of the virtual antenna via the first communication unit 901 or the second communication unit 902. The AI / ML function unit 904 executes various processes using AI or ML. For example, the AI / ML function unit 904 may execute the above-mentioned CSI compression and beam selection. In addition, the AI / ML function unit 904 generates and updates a trained model by machine learning as necessary. For example, the AI / ML function unit 904 updates the trained model when the trained model becomes inappropriate due to an environmental change or the like. Furthermore, the AI / ML functional unit 904 executes the above-mentioned various control communications associated with the use of AI / ML, for example, via the second communication unit 902. For example, the AI / ML functional unit 904 can notify the base station device 151 of a change in capability information of the terminal device 101 when it becomes necessary to update a trained model related to compression and decompression of CSI.

[0063] 10 shows a functional configuration example of the communication function unit 131 and the control unit 501 (i.e., the parts other than the relay function unit 132) of the relay devices 121 and 122. The parts other than the relay function unit 132 of the relay devices 121 and 122 include a communication unit 1001, a capability information notifying unit 1002, and a measurement result notifying unit 1003 as their functions. These functions can be implemented, for example, by the processor 801 executing a program stored in the ROM 802 or the storage device 804, or by the communication circuit 805. However, this is just an example, and the functions of FIG. 10 may be realized by other configurations. Also, the functions shown in FIG. 10 are just an example, and the above-mentioned various processes may be realized by other functional units.

[0064] The communication unit 1001 has a function corresponding to the first communication unit 901 of the terminal device 101. That is, when the first communication unit 901 performs communication using the side link communication function, the communication unit 1001 also has the side link communication function. The capability information notifying unit 1002 notifies, for example, the terminal device 101 of the capability information of the relay function unit 132 via the communication unit 1001. For example, the capability information notifying unit 1001 notifies the terminal device 101 of whether or not the relay function unit 132 is included, the frequency band that the relay function unit 132 can use, and the number and configuration of antennas that can be used in the relay function unit 132. The measurement result notifying unit 1003 measures, for example, the wireless quality of a signal received in the relay function unit 132, and notifies the terminal device 101 of the measurement result. The measurement result notifying unit 1003 is configured to monitor, for example, the received power of a signal at each antenna of the relay function unit 132 to acquire the wireless quality.

[0065] As described above, the terminal device 101 according to this embodiment can use the relay device having an RF relay function as an extended antenna by performing appropriate control to communicate with the base station device 151. This makes it possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0066] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A terminal device in a wireless communication system including a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency, amplifies the signal, and relays the signal to the base station device, and converts a signal of the second frequency transmitted by the base station device to the first frequency, amplifies the signal, and relays the signal to the terminal device, The relay device includes a relay means for converting and amplifying a frequency of a received signal and relaying the signal without demodulating or decoding the signal, and a communication means for communicating with the terminal device, the communication means being different from the relay means; the terminal device has an acquisition means for acquiring capability information related to the relay means of the relay device via the communication means of the relay device; A terminal device comprising:

2. 2. The terminal device according to claim 1, wherein the capability information includes information indicating that the relay device has the relay means.

3. The terminal device according to claim 1 , wherein the capability information includes information indicating at least one of a frequency that can be used as the first frequency and a frequency that can be used as the second frequency.

4. The terminal device according to claim 1 , wherein the capability information includes information regarding the number and configuration of antennas possessed by the relay device.

5. The terminal device according to claim 1 , wherein the acquisition means acquires the capability information by using 3GPP sidelink communication.

6. A relay device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency, amplifies the signal, and relays the signal to the base station device, and converts a signal of the second frequency transmitted by the base station device to the first frequency, amplifies the signal, and relays the signal to the terminal device, A relay means for converting and amplifying a frequency of a received signal and relaying the signal without demodulating or decoding the signal; a communication means for communicating with the terminal device, the communication means being different from the relay means; The communication unit notifies the terminal device of capability information relating to the relay unit of the relay device.

13. A relay device comprising:

7. 7. The relay device according to claim 6, wherein the capability information includes information indicating that the relay device has the relay means.

8. 7. The relay device according to claim 6, wherein the capability information includes information indicating at least one of a frequency that can be used as the first frequency and a frequency that can be used as the second frequency.

9. The relay device of claim 6 , wherein the capability information includes information regarding the number and configuration of antennas that the relay device has.

10. 7. The relay device according to claim 6, wherein the communication unit notifies the capability information by using 3GPP sidelink communication.

11. A control method executed by a terminal device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency, amplifies the signal, and relays the signal to the base station device, and converts a signal of the second frequency transmitted by the base station device to the first frequency, amplifies the signal, and relays the signal to the terminal device, comprising: The relay device includes a relay means for converting and amplifying a frequency of a received signal and relaying the signal without demodulating or decoding the signal, and a communication means for communicating with the terminal device, the communication means being different from the relay means; The control method, comprising: acquiring capability information relating to the relay means of the relay device via the communication means of the relay device.

12. A control method executed by a relay device in a wireless communication system including a terminal device, a base station device to which the terminal device is connected, and a relay device that converts a signal of a first frequency transmitted by the terminal device to a second frequency, amplifies the signal, and relays the signal to the base station device, and converts a signal of the second frequency transmitted by the base station device to the first frequency, amplifies the signal, and relays the signal to the terminal device, comprising: The relay device includes a relay means for converting and amplifying a frequency of a received signal and relaying the signal without demodulating or decoding the signal, and a communication means for communicating with the terminal device, the communication means being different from the relay means; The control method, comprising: notifying the terminal device of capability information relating to the relay means of the relay device, using the communication means.

13. A program for causing a computer installed in a terminal device to execute the control method according to claim 11.

14. A program for causing a computer provided in a relay device to execute the control method according to claim 12.

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