Wireless communication system, wireless communication method, wireless communication processing device, and wireless communication processing program

Abstract

In the present invention, the following processing is performed in a learning phase. A base station device 20 is caused to transmit a control signal toward a relay device 22. The relay device 22 dynamically selects a phase weight for determining a beam direction of a reflected wave in accordance with a set value. A channel state of CH2 is estimated from a CH2 reference signal of a low frequency arrived from a terminal device 24 to the base station device 20. Communication quality of CH1 is measured from a CH1 reference signal of a high frequency arrived from the terminal device 24 to the base station device 20. The set value, the channel state, and the communication quality are learned to generate a learning model. In an estimation phase, the latest channel state obtained in CH2 is applied to the learning model to estimate an optimum set value predicted to make the communication quality best under the latest state.

Description

[Technical Field]

[0001] This disclosure relates to a wireless communication system, a wireless communication method, a wireless communication processing device, and a wireless communication processing program, and in particular to a wireless communication system, a wireless communication method, a wireless communication processing device, and a wireless communication processing program that are suitable when using a repeater capable of dynamic control of beam direction. [Background technology]

[0002] Non-Patent Documents 1 and 2 below disclose wireless communication systems that use relay devices that can dynamically control beam directions.

[0003] Fig. 1 shows an example of a conventional wireless communication system that uses a relay device having the above-mentioned functions. The system shown in Fig. 1 includes a wireless communication base station device 10. The base station device 10 has a function of transmitting multiple beams. Here, it is assumed that the number of transmission beams of the base station device 10 is Ntx.

[0004] The system shown in FIG. 1 also includes a relay device 12 and a terminal device 14. The relay device 12 may be one or more. FIG. 1 shows an example configuration including M relay devices 12. The relay device 12 has the function of relaying wireless signals between the base station device 10 and the terminal device 14. Specifically, the relay device 12 is configured as a reflector or repeater that can dynamically control the beam direction. The relay device 12 can also generate multiple relay beams. Here, it is assumed that the number of relay beams generated by the relay device 12 is Nrelay.

[0005] The terminal device 14 can establish wireless communication with the base station device 10 directly or via the relay device 12. The terminal device 14 can also generate multiple beams. Here, it is assumed that the number of terminal beams emitted by the terminal device 14 is Nrx.

[0006] 1, a plurality of wireless propagation paths can be formed between a base station device 10 and a terminal device 14 using a plurality of relay devices 12. This makes it possible to obtain path diversity, an expansion effect of the number of MIMO multiplexing, and the like, and to obtain high communication efficiency. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] HJ Kwon et al., “Machine Learning-Based Beamforming…”, IEEE Access, Vol. 9, pp. 28066-28075 (2021). [Non-patent document 2] K. Diamantaras et al., “Optimal Mobile Relay Beamforming…”, 2019 IEEE 29th International Workshop on Machine Learning for Signal Processing (2019). Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming, Qingqing Wu, Rui Zhang, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, p5394-5409, VOL. 18, NO. 11, November 2019 Summary of the Invention [Problem to be solved by the invention]

[0008] In the conventional wireless communication system described above, in order for the relay device 12 to properly relay signals between the base station device 10 and the terminal device 14, it is necessary to set an appropriate beam direction in the relay device 12. However, the relay device 12 cannot control the beam direction by itself. Therefore, in the wireless communication system described above, it becomes necessary to search for the beam direction for each combination of beams and then instruct the relay device 12 to select the optimal beam direction.

[0009] Here, the number of beam searches L required for the system shown in FIG. 1 is enormous, as shown in the following equation. L = (Number of transmitting beams Ntx) * (Number of relay beams Nrelay) * (Number of relay devices M) * (Number of terminal beams Nrx)

[0010] Therefore, in the wireless communication system as shown in FIG. 1, there is a problem in that the overhead of searching for combinations of beams including the relay device 12 becomes large.

[0011] The present disclosure has been made in consideration of the above-mentioned problems, and has as its first object to provide a wireless communication system that can sufficiently reduce the overhead associated with beam selection in a relay device while using a relay device that can dynamically control the beam direction.

[0012] A second object of the present disclosure is to provide a wireless communication method that uses a relay device capable of dynamically controlling the beam direction, while being able to sufficiently reduce the overhead required for beam selection in the relay device.

[0013] A third object of the present disclosure is to provide a wireless communication processing device that uses a relay device capable of dynamically controlling the beam direction and that can sufficiently reduce the overhead required for beam selection in the relay device.

[0014] Furthermore, a fourth object of the present disclosure is to provide a wireless communication processing program for sufficiently reducing the overhead involved in beam selection in a relay device while using a relay device capable of dynamically controlling the beam direction. [Means for solving the problem]

[0015] In order to achieve the above object, a first aspect is a wireless communication system including a base station device, a relay device, and a terminal device, the base station device is configured to provide a control signal including a setting value to the relay device; the relay device is configured to dynamically select a phase weight that determines a beam direction of a reflected wave in accordance with the set value; the terminal device is configured to transmit a low-frequency reference signal and a high-frequency reference signal; During the learning phase, a process of causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; and executing a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on the plurality of data sets; In the estimation phase, a process of estimating a latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; It is desirable that the communication device further comprises a processing device configured to execute a process of causing the base station device to transmit a control signal including the optimum setting value.

[0016] A second aspect is a wireless communication method for realizing wireless communication using a base station device, a relay device, and a terminal device, comprising: a step of the base station device providing a control signal including a setting value to the relay device; the relay device dynamically selecting a phase weight that determines a beam direction of a reflected wave in accordance with the set value; a step of transmitting a low frequency reference signal and a high frequency reference signal by the terminal device; During the learning phase, causing the base station device to transmit the control signal to the relay device; estimating, from the low-frequency reference signal that has arrived at the base station device, a state of a channel that transmits the low-frequency signal; measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, estimating the latest state of the channel from the low-frequency reference signal arriving at the base station device; A step of fitting the latest state to the learning model to estimate optimal setting values that are predicted to maximize the communication quality under the latest state; transmitting a control signal including the optimum setting value to the base station device; It is desirable to include:

[0017] A third aspect is a wireless communication processing device for realizing wireless communication using a base station device that transmits a control signal including a setting value, a relay device that receives the control signal and dynamically selects a phase weight that determines a beam direction of a reflected wave in accordance with the setting value, and a terminal device that transmits a low-frequency reference signal and a high-frequency reference signal, During the learning phase, causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, a process of estimating a latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; a process of transmitting a control signal including the optimal setting value to the base station device; Preferably, the system is configured to execute the following:

[0018] A fourth aspect is a wireless communication processing program for realizing wireless communication using a base station device that transmits a control signal including a setting value, a relay device that receives the control signal and dynamically selects a phase weight that determines a beam direction of a reflected wave in accordance with the setting value, and a terminal device that transmits a low-frequency reference signal and a high-frequency reference signal, During the learning phase, causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, a process of estimating a latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; a process of transmitting a control signal including the optimal setting value to the base station device; It is preferable that the program include a program that causes the processing unit to execute the above. [Effects of the Invention]

[0019] According to the first to fourth aspects, it is possible to sufficiently reduce the overhead required for beam selection in the relay device while using a relay device capable of dynamically controlling the beam direction. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a conventional wireless communication system using a relay device. [Figure 2] FIG. 2 is a diagram for explaining an overview of a learning phase according to the first embodiment of the present disclosure. [Figure 3] FIG. 2 is a diagram for explaining an outline of an estimation phase according to the first embodiment of the present disclosure. [Figure 4]1 is a block diagram illustrating a configuration of a wireless communication system according to a first embodiment of the present disclosure. [Figure 5] 1 is a block diagram illustrating a configuration of a processing device included in a wireless communication system according to a first embodiment of the present disclosure. [Figure 6] 1 is a block diagram illustrating a configuration of a base station device included in a wireless communication system according to a first embodiment of the present disclosure. [Figure 7] 2 is a block diagram illustrating a configuration of a relay device included in the wireless communication system according to the first embodiment of the present disclosure. FIG. [Figure 8] 1 is a block diagram illustrating a configuration of a terminal device included in a wireless communication system according to a first embodiment of the present disclosure. [Figure 9] 4 is a flowchart illustrating an operation in a learning phase according to the first embodiment of the present disclosure. [Figure 10] 4 is a flowchart illustrating an operation in an estimation phase according to the first embodiment of the present disclosure. [Figure 11] FIG. 10 is a block diagram illustrating a configuration of a second example of a relay device that can be used in the first embodiment of the present disclosure. [Figure 12] FIG. 10 is a block diagram illustrating the configuration of a second example of a terminal device that can be used in the first embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0021] Embodiment 1 [Features of the first embodiment] 2 is a diagram illustrating the operation of the learning phase, which is a first feature of the first embodiment of the present disclosure. The wireless communication system of this embodiment includes a base station device 20, a relay device 22, and a terminal device 24.

[0022] In the learning phase, the following processing is executed to learn the relationship between the radio propagation path between the base station device 20 and the terminal device 24 and the phase weight used in the relay device 22.

[0023] (1) The base station device 20 transmits a control signal to the relay device 22. (2) The repeater 22 receives the control signal and sets a phase weight that determines the reflection direction of the beam. (3) The terminal device 24 outputs a high-frequency millimeter wave signal as a measurement signal. The measurement signal reaches the base station device 20 via the relay device 22. The base station device 20 detects the communication quality in the high frequency band based on the received measurement signal. Hereinafter, the result detected in this manner is referred to as "millimeter wave quality." (4) The terminal device 24 further transmits CSI (Channel State Information) on a low-frequency signal to estimate the channel state. The CSI includes information indicating the state of the channel that constitutes the wireless propagation path, such as scattering, attenuation, and power attenuation. The CSI is received by the base station device 20 as shown in the figure.

[0024] (5) The base station device 20 stores three pieces of data, namely, the "phase weight" set by the relay device 22, the "low frequency CSI" received from the terminal device 24, and the "millimeter wave quality" received via the relay device 22, as a data set, and performs machine learning processing. This allows the base station device 20 to learn what "millimeter wave quality" can be obtained by setting what "phase weight" under what "low frequency CSI."

[0025] 3 is a diagram illustrating the operation of the estimation phase, which is a second feature of the first embodiment of the present disclosure. In the estimation phase, the following processing is executed to estimate phase weights that achieve the best communication quality based on the learning model learned in the learning phase.

[0026] (1) The terminal device 24 transmits low-frequency CSI. The low-frequency CSI includes information indicating the latest state of the radio propagation path and is received by the base station device 20. (2) In the base station device 20, the channel state indicated by the low-frequency CSI is applied to the above learning model, and a phase weight that realizes optimal communication quality under the current state is estimated. (3) The base station device 20 transmits a control signal to the relay device 22 to convey the estimated phase weight. (4) The repeater 22 sets the phase weight specified by the control signal, so that the beam of the repeater 22 is directed in a direction that achieves efficient relaying. (5) After that, a transmission signal using a high frequency millimeter wave is transmitted between the base station device 20 and the terminal device 24.

[0027] As described above, in the wireless communication system of this embodiment, beam setting for the relay device 22 can be performed remotely from the base station device 20. Furthermore, by using a learning model generated in advance, the optimal phase weight can be easily determined without incurring a large search load. Therefore, according to this system, even if the number of transmission beams Ntx, the number of relay beams Nrelay, the number of relay devices M, and the number of terminal beams Nrx are large, optimal beam setting can be achieved without causing excessive search overhead.

[0028] [Configuration of the First Embodiment] 4 is a block diagram illustrating the overall configuration of a wireless communication system according to this embodiment. The system according to this embodiment includes a base station device 20, a relay device 22, a terminal device 24, and a processing device 25. The number of base station devices 20 is not limited to one, and multiple devices may be used. Similarly, the number of relay devices 22 and terminal devices 24 may each be multiple.

[0029] The processing device 25 has the function of collecting, storing, and processing information received and demodulated by the base station device 20. The learning of the data set and the estimation process using the learning model described above are executed in the processing device 25.

[0030] Both the base station device 20 and the terminal device 24 have the function of transmitting and receiving signals in two or more different frequency bands. In the example shown in Fig. 4, the base station device 20 and the terminal device 24 each have a transceiver for channel 1 (CH1) and a transceiver for channel 2 (CH2). In this embodiment, it is assumed that data communication in a high frequency band, i.e., millimeter waves, is performed in CH1, and communication in a low frequency band is performed in CH2.

[0031] However, the combination of CH and frequency band is not limited to this, and CH1 may be used for communication in a low frequency band and CH2 for communication in a high frequency band. Furthermore, the frequency band used for communication is not limited to the one exemplified in this embodiment. Furthermore, it does not matter whether the frequency band is a licensed band or an unlicensed band.

[0032] The relay device 22 is arranged to relay a transmission signal from the base station device 20 or the terminal device 24 to transmit it to the other side. By using the relay device 22, it is possible to avoid obstacles that exist between the base station device 20 and the terminal device 24. In addition, it is possible to obtain a spatial multiplexing effect by increasing the number of propagation paths. The relay device 22 has a communication device for receiving control signals. This allows the relay device 22 to be controlled and managed remotely.

[0033] The control signal is transmitted, for example, from base station device 20. While Fig. 4 shows an example in which base station device 20 communicating with terminal device 24 transmits the control signal, the control signal may also be transmitted from another base station device to relay device 23. The line for notifying the control signal may be wired or wireless, and the notification method may also be irrelevant. Processing can be performed in the same way even when there are multiple relay devices 22.

[0034] Fig. 5 is a block diagram for functionally explaining the configuration of the processing device 25. In addition to dedicated hardware, the processing device 25 includes an arithmetic processing unit and memory. Specifically, the functions of each part shown in Fig. 5 are realized by the arithmetic processing unit working in cooperation with the dedicated hardware to carry out processing in accordance with a program stored in the memory.

[0035] The processing device 25 includes a base station device IF 26. The base station device IF 26 is an interface for receiving information transferred from the base station device 20 and for transmitting a notification from the processing device 25 to the base station device 20. The information received by the base station device IF 26 includes information on millimeter wave quality obtained in CH1 and low frequency CSI obtained in CH2, i.e., channel information of the wireless propagation path.

[0036] The processing device 25 includes a database unit 28. The database unit 28 stores, as a data set, information transferred from the base station device 20 and the setting values of the phase weights provided to the relay device 22. Specifically, after the setting values for the phase weights are notified to the relay device 22, the processing device 25 stores, in the database unit 28, information on the millimeter wave quality of CH1 and the channel information of CH2 transmitted from the terminal device 24 in association with the setting values until the setting values are updated. When learning about all or a large number of setting values that can be adopted by the relay device 22 is completed, the processing device 25 is ready to select the setting values that provide the best communication quality for CH1.

[0037] The processing device 25 further includes a learning processing unit 30 and an estimation processing unit 32. The learning processing unit 30 calculates a learning model using a large number of data sets stored in the database unit 28. Meanwhile, the estimation processing unit 32 estimates setting values to be set in the relay device 22 to obtain the best millimeter wave quality by applying channel information acquired via the base station device IF 26 to the learning model generated by the learning processing unit 30. The setting values may be estimated directly by the estimation processing unit 32 from the channel information. Alternatively, the estimation processing unit 32 may estimate the communication quality of CH1 corresponding to the provisionally determined setting values from the channel information, and select setting values that provide the best estimated quality of CH1.

[0038] Fig. 6 is a block diagram for functionally explaining the configuration of base station device 20. Base station device 20 also includes a calculation processing unit and memory in addition to dedicated hardware. Specifically, the functions of each part shown in Fig. 6 are realized by the calculation processing unit working in cooperation with the dedicated hardware to carry out processing in accordance with a program stored in the memory.

[0039] The base station device 20 includes a CH1 transceiver 34 and a CH2 transceiver 36. The CH1 transceiver 34 has a function for performing wireless communication in a high frequency band, while the CH2 transceiver 36 has a function for performing wireless communication in a low frequency band.

[0040] The base station device 20 includes a quality acquisition unit 38 and an information acquisition unit 40. The quality acquisition unit 38 measures indicators related to the communication quality of CH1 based on a measurement signal transmitted through CH1. Specifically, it measures RSSI (Received Signal Strength Indicator), RSRQ (Reference Signal Received Quality), RSRP (Reference Signal Received Power), SINR (Signal-to-Interference-plus-Noise Ratio), throughput, received power, delay time, etc. Meanwhile, the information acquisition unit 40 acquires channel information for CH2 by channel estimation using low-frequency CSI transmitted through CH2.

[0041] The base station device 20 also includes a processing device IF 42. The processing device IF 42 is an interface for transferring information acquired by the base station device 20 to the processing device 25 and for receiving information notified from the processing device 25.

[0042] The base station device 20 further includes a control signal generator 44. The control signal generator 44 has a function of generating a control signal to be notified to the relay device 22 based on information notified from the processing device 25. The control signal includes information on the phase weight to be set in the relay device 22.

[0043] Fig. 7 is a block diagram for functionally explaining the configuration of relay device 22. Relay device 22 also includes a processing unit and memory in addition to dedicated hardware. Specifically, the functions of each part shown in Fig. 7 are realized by the processing unit working in cooperation with the dedicated hardware to carry out processing according to a program stored in the memory.

[0044] Fig. 7 specifically shows the structure of a relay device 22 configured as an intelligent reflector. The relay device 22 shown in Fig. 7 includes a control management communication unit 46. The control management communication unit 46 receives a control signal transmitted from the base station device 20 and acquires a setting value included in the control signal.

[0045] The repeater 22 also includes a weight setting unit 48 and a reflector 50. The weight setting unit 48 determines the phase weight to be provided to the reflector 50 based on the setting value acquired by the control management communication unit 46. For example, if a reflection angle to be achieved by the repeater 22 is specified as the setting value, the phase weight is determined so that the millimeter wave signal of CH1 is reflected at the specified angle.

[0046] The reflecting unit 50 includes a plurality of reflecting elements. Each reflecting element shifts the phase of the reflected radio waves to reflect the high-frequency radio waves arriving through CH1 in the intended direction. The reflecting unit 50 can dynamically and arbitrarily control the reflection direction of the radio waves by setting a different phase shift amount for each reflecting element as a phase weight.

[0047] Fig. 8 is a block diagram for functionally explaining the configuration of the terminal device 24. The terminal device 24 also includes a processing unit and memory in addition to dedicated hardware. Specifically, the functions of each part shown in Fig. 8 are realized by the processing unit working in cooperation with the dedicated hardware to carry out processing in accordance with a program stored in the memory.

[0048] The terminal device 24 includes a CH1 transceiver 52 and a CH2 transceiver 54. The CH1 transceiver 52 has a function for performing wireless communication in a high frequency band, while the CH2 transceiver 54 has a function for performing wireless communication in a low frequency band.

[0049] The terminal device 24 also includes a CH1 reference signal generator 56 and a CH2 reference signal generator 58. The CH1 reference signal generator 56 generates a reference signal for measuring the radio quality of CH1, i.e., a signal indicated as "measurement signal (millimeter wave)" in Fig. 2 and Fig. 3. On the other hand, the CH2 reference signal generator 58 generates a reference signal for performing channel estimation of CH2, i.e., a signal indicated as "channel estimation (low frequency)" in Fig. 2 or Fig. 3.

[0050] The reference signals generated by the CH1 reference signal generator 56 or the CH2 reference signal generator 58 are transmitted from the CH1 transceiver 52 or the CH2 transceiver 54 via the transmission timing controller 60. The transmission timing controller 60 has a function of adjusting the transmission timing of these reference signals. Specifically, the transmission timing controller 60 adjusts the transmission timing of these reference signals so that measurements of CH1 and CH2 can be performed simultaneously or within a certain time error range.

[0051] [Processing flow in the first embodiment] 9 shows a flowchart for explaining the flow of processing executed in the learning phase in the wireless communication system of this embodiment. First, a transmission trigger is transmitted from the processing device 25 (100). Note that the transmission trigger may be generated by the base station device 20 instead of the processing device 25.

[0052] Upon receiving the transmission trigger, the base station device 20 transmits a control signal to the relay device 22 (step 102). The relay device 22 sets relay parameters such as a phase weight, a beam weight, or a beam angle based on the information contained in the control signal (step 104).

[0053] The terminal device 24 transmits a reference signal for CH1 and a reference signal for CH2 (steps 106, 108). These reference signals are transmitted simultaneously or within an allowable time error range. A transmission trigger for the reference signals may be provided to the terminal device 24 via the relay device 22, or may be periodically generated by the terminal device 24 itself.

[0054] Base station device 20 receives the reference signal of CH1 and measures the communication quality of CH1 measured by that signal (step 110). Specifically, as described above, it measures RSSI, RSRQ, RSRP, SINR, throughput, received power, delay time, etc. Base station device 20 also receives the reference signal of CH2 and performs channel estimation for CH2 based on that signal (step 112). Then, the quality measurement result of CH1 and the channel estimation result of CH2 are transferred to processing device 25 (step 114). Note that the quality measurement and channel estimation results may be processed by calculation before being transferred.

[0055] The processing device 25 stores the above information transferred from the base station device 20 and the setting value provided to the relay device 22 on the control signal as a set of data in the database unit 28 (step 116). Thereafter, the processing of steps 106 to 116 described above is repeated for a fixed period of time. The fixed period is set to a time during which a predetermined number of data sets are obtained for one setting value. During this time, the terminal device 24 may be stationary or moving.

[0056] After the above-mentioned fixed period has elapsed, that is, after a predetermined number of data sets have been acquired for one setting value, a new control signal is provided to the relay device 22, and the setting value is updated. By repeating this process, information is collected regarding the relationship between the communication quality of CH1, the channel state of CH2, and the setting value of the relay device.

[0057] Once information has been collected about many or all of the setting values that can be adopted by the relay device 22, a learning process is performed (step 118). The learning process is performed by the processing device 25. By the learning process of this step, a learning model that associates the state of CH2, the setting values of the relay device 22, and the communication quality in CH1 is obtained.

[0058] In this embodiment, CSI for CH2 may be acquired from the reference signal of CH2, and the arrival direction of the reference signal as seen from the base station device 20 may be estimated from the CSI. When the arrival direction of the reference signal is estimated, a learning model may be created using the arrival direction as a main factor representing the state of CH2.

[0059] 10 shows a flowchart for explaining the flow of processing executed in the estimation phase in the wireless communication system of this embodiment. The estimation phase starts after the learning phase ends. The processing of the estimation phase starts when the terminal device 24 transmits a reference signal on CH2 (step 120).

[0060] When the base station device 20 receives the reference signal for CH2, it performs channel estimation for CH2 using that signal (step 122).Then, the estimation result is transferred to the processing device 25 (step 124).

[0061] Processing device 25 applies the channel estimation results to the learning model obtained in the learning process to estimate setting values to be set in relay device 22 (step 126). The estimation results are notified to base station device 20 (step 128). Then, base station device 20 adds the notified information to a control signal and transmits it to the relay device (step 130).

[0062] The relay device 22 changes the setting value that determines the beam direction based on the information added to the control signal (step 132). Thereafter, data is transmitted and received between the base station device 20 and the terminal device 24 (steps 134, 136).

[0063] 10 shows how the terminal device 24 periodically generates a reference signal for CH2, resulting in periodically updating the setting value of the relay device 22. By repeating this process, the wireless communication system of this embodiment can make the setting of the relay device 22 follow environmental changes in the wireless propagation path. Therefore, the wireless communication system of this embodiment can maintain efficient wireless communication for a long period of time.

[0064] As described above, according to the wireless communication system of this embodiment, by using the learning model learned in the learning phase, it is possible to issue optimal setting values to the relay device 22 in the estimation phase without requiring a large search load. Therefore, according to the wireless communication system of this embodiment, it is possible to sufficiently reduce the overhead required for beam selection in the relay device 22 while using a relay device 22 that can dynamically control the beam direction.

[0065] [Modification of the first embodiment] In the first embodiment described above, the learning phase and the estimation phase are performed separately and independently. However, the present disclosure is not limited to this. For example, in the estimation phase, the terminal device 24 may transmit a reference signal for CH1 together with a reference signal for CH2, and information may be collected in the same manner as in the learning phase.

[0066] Furthermore, the learning phase and the estimation phase do not necessarily have to be performed serially, but may be performed in parallel, which allows the learning model to be updated in real time while estimating the optimal beam settings.

[0067] In the first embodiment described above, an intelligent reflector is used as the relay device 22. However, the present disclosure is not limited to this, and a smart repeater may be used as the relay device 22.

[0068] Fig. 11 shows the configuration of a relay device 62 using a smart repeater that can be used in this embodiment. In Fig. 11, blocks that are the same as those shown in Fig. 7 are given the same reference numerals, and their explanations will be omitted or simplified.

[0069] As shown in FIG. 11, a relay device 62 using a smart repeater includes a user-side antenna unit 64. The user-side antenna unit 64 is an antenna unit for communicating with a user, i.e., a terminal device 24. The user-side antenna unit 64 has multiple antenna elements and is capable of forming beams. Each antenna element is connected to a variable phase shifter. The direction of the beam formed by the relay device 62 can be dynamically controlled by controlling the phase amount (phase weight) added to each element by the variable phase shifter.

[0070] The relay device 62 includes a base station antenna unit 66. The base station antenna unit 66 is an antenna unit for communicating with the base station device 20. The base station antenna unit 66 is also capable of beamforming, similar to the user-side antenna unit.

[0071] The relay device 62 further includes an amplifier 68. The amplifier 68 has a function of amplifying the power of a signal received by the user-side antenna 64 or the base station-side antenna 66. The amplifier 68 may also have a function of performing frequency conversion on the received signal. In addition, to support transmission using TDD (Time Division Duplex), the amplifier 68 may be provided with amplifiers corresponding to the uplink and downlink directions, respectively. In this case, the uplink and downlink timing may be separately obtained via the control and management communication unit 46, and the two amplifiers may be switched in accordance with that timing.

[0072] Relay device 62 having the above-described functions can dynamically control the beam direction based on the control signal provided from base station device 20, and can appropriately relay radio signals between base station device 20 and terminal device 24. Therefore, even if relay device 22 shown in Fig. 7 is replaced with relay device 62 shown in Fig. 11, the above-described excellent effects can be similarly obtained.

[0073] Embodiment 2 Fig. 12 is a block diagram for functionally explaining the configuration of a terminal device 70 used in the second embodiment of the present disclosure. The wireless communication system of this embodiment can be realized by a hardware configuration substantially similar to that of the first embodiment, except that the terminal device 24 described with reference to Fig. 8 is replaced with the terminal device 70 shown in Fig. 12. Note that in Fig. 12, explanations of blocks corresponding to those shown in Fig. 8 will be omitted or simplified.

[0074] The terminal device 70 used in this embodiment includes a terminal positioning unit 72. The terminal positioning unit 72 has a function of estimating the position of the terminal device 70. The position of the terminal device 70 is estimated by, for example, positioning using a Global Navigation Satellite System (GNSS), indoor positioning, self-position estimation, or the like.

[0075] The terminal device 70 further includes a terminal information generation unit 74. The terminal information generation unit 74 has a function of generating, as notification information, the terminal location information acquired by the terminal positioning unit 72. The terminal location information may be included in the reference signal of CH2 and notified, or may be included in a different signal and transmitted using CH2. When the terminal location information is included in a signal different from the reference signal, the transmission timing control unit 60 controls the transmission timing so that the signal is transmitted simultaneously with the reference signals of CH1 and CH2 or within a certain time error range.

[0076] A signal including the location information of the terminal device 70 is received by the base station device 20 together with a reference signal of CH1 or CH2. In this embodiment, the information acquisition unit 40 of the base station device 20 has a function of acquiring the terminal location information from the signal. The terminal location information is then transferred from the base station device 20 to the processing device 25.

[0077] In the learning phase, the processing device 25 stores the terminal location information in a data set in the database unit 28. Then, the learning processing unit 30 generates a learning model using the terminal location information as one element. Therefore, in this embodiment, a learning model based on the relationship between the state of CH2, the position of the terminal device 70, the setting value of the relay device 22, and the communication quality of CH1 can be obtained.

[0078] In the estimation phase, the processing device 25 first acquires the state of CH2 and the position of the terminal device 70. Then, the processing device 25, in the estimation processing unit 32, estimates the setting value of the relay device 22 that will bring about the best communication quality for CH1 under the current position of CH2 and the current position of the terminal device 70.

[0079] As described above, in this embodiment, a learning model can be generated that includes the position of the terminal device 70. Then, using this learning model, the setting values of the relay device 22 can be determined, taking into consideration the position of the terminal device 70. Therefore, according to the wireless communication system of this embodiment, the setting accuracy of the beam direction can be further improved compared to the first embodiment, and communication efficiency can be improved. [Explanation of symbols]

[0080] 20 Base station equipment 22, 62 Relay equipment 24, 70 Terminal equipment 25 Processing equipment 28 Database Department 30 Learning processing unit 32 Estimation processing unit 34, 52 CH1 transmitter / receiver 36, 54 CH2 transceiver 38 Quality Acquisition Department 40 Information acquisition department 44 Control signal generation unit 48 Weight setting section 50 Reflector 56 CH1 reference signal generation section 58 CH2 reference signal generation section 60 Transmission timing control section 72 Terminal positioning unit 74 Terminal information generation unit

Claims

1. A wireless communication system including a base station device, a relay device, and a terminal device, the base station device is configured to provide a control signal including a setting value to the relay device; the relay device is configured to dynamically select a phase weight that determines a beam direction of a reflected wave in accordance with the set value; the terminal device is configured to transmit a low-frequency reference signal and a high-frequency reference signal; During the learning phase, a process of causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; and executing a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on the plurality of data sets; In the estimation phase, a process of estimating a latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; a processing unit configured to cause the base station device to transmit a control signal including the optimal setting value.

2. The wireless communication system according to claim 1 , wherein the channel condition includes a direction of arrival of the low-frequency reference signal when it arrives at the base station device.

3. The terminal device A process of determining the location of the terminal itself; transmitting a signal including information about the terminal location on the low frequency channel; the data set includes the terminal location in addition to the setting values, the channel conditions, and the communication quality; the learning model defines a relationship between the setting value, the channel state, the communication quality, and the terminal location; the processing device is configured to further execute, in the estimation phase, a process of estimating a latest terminal position of the terminal device from the low-frequency signal arriving at the base station device; The wireless communication system described in claim 1 or 2, wherein the process of estimating the optimal setting value involves fitting the latest terminal position together with the latest state into the learning model to estimate the optimal setting value that is predicted to maximize the communication quality under the latest state.

4. 4. The wireless communication system according to claim 1, wherein the terminal device is configured to transmit the low-frequency reference signal and the high-frequency reference signal so that the difference between their transmission timings is within an acceptable range.

5. 5. The wireless communication system according to claim 1, wherein the relay device is an intelligent reflector having a reflecting section that reflects the high-frequency signal between the base station device and the terminal device, or a smart repeater having a base station side antenna section for communicating with the base station device, a user side antenna section for communicating with the terminal device, and an amplifier section that connects them.

6. A wireless communication method for realizing wireless communication using a base station device, a relay device, and a terminal device, comprising: a step of the base station device providing a control signal including a setting value to the relay device; the relay device dynamically selecting a phase weight that determines a beam direction of a reflected wave in accordance with the set value; a step of transmitting a low frequency reference signal and a high frequency reference signal by the terminal device; During the learning phase, causing the base station device to transmit the control signal to the relay device; estimating, from the low-frequency reference signal that has arrived at the base station device, a state of a channel that transmits the low-frequency signal; measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, estimating the latest state of the channel from the low-frequency reference signal arriving at the base station device; A step of fitting the latest state to the learning model to estimate optimal setting values that are predicted to maximize the communication quality under the latest state; transmitting a control signal including the optimum setting value to the base station device; A wireless communication method comprising:

7. A wireless communication processing device for realizing wireless communication using a base station device that transmits a control signal including a setting value, a relay device that receives the control signal and dynamically selects a phase weight that determines a beam direction of a reflected wave in accordance with the setting value, and a terminal device that transmits a low-frequency reference signal and a high-frequency reference signal, During the learning phase, causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, a process of estimating a latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; a process of transmitting a control signal including the optimal setting value to the base station device; a wireless communication processing device configured to execute

8. A wireless communication processing program for realizing wireless communication using a base station device that transmits a control signal including a setting value, a relay device that receives the control signal and dynamically selects a phase weight that determines a beam direction of a reflected wave in accordance with the setting value, and a terminal device that transmits a low-frequency reference signal and a high-frequency reference signal, During the learning phase, causing the base station device to transmit the control signal to the relay device; a process of estimating a state of a channel transmitting a low-frequency signal from the low-frequency reference signal that has arrived at the base station device; a process of measuring communication quality at the high frequency from the high frequency reference signal that has arrived at the base station device; a process of storing a data set including the setting value included in the control signal, the channel state, and the communication quality in a database unit; a process of learning a learning model that defines a relationship between the setting value, the channel state, and the communication quality based on a plurality of the data sets; In the estimation phase, a process of estimating the latest state of the channel from the low-frequency reference signal arriving at the base station device; A process of fitting the latest state to the learning model and estimating optimal setting values that are predicted to maximize the communication quality under the latest state; a process of transmitting a control signal including the optimal setting value to the base station device; A wireless communication processing program including a program that causes an arithmetic processing unit to execute the above.

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