JP7521611B2 - Radio relay control method and radio relay device - Google Patents

Description

The present invention relates to a technology for relaying radio waves of wireless communication between a wireless base station and a wireless terminal by reflecting them using a dynamic reflector.

In order to realize high-speed, high-capacity wireless access, the use of high-frequency bands that can secure wide bandwidth is attracting attention. For example, the 5th generation mobile communication system realizes high-speed, high-capacity communication using the 28 GHz band. As another example, the wireless LAN standard IEEE802.11ad (millimeter wave wireless LAN system) realizes high-speed, high-capacity communication using the 60 GHz band.

High-frequency radio waves are more susceptible to attenuation and diffraction than low-frequency radio waves. As a result, issues with using high-frequency bands include shorter transmission distances due to radio wave attenuation and poor reception quality due to obstructions such as obstacles.

To compensate for radio wave attenuation, beamforming using multi-element antennas at the transmitting and receiving stations is effective. In this case, the beamforming gain can compensate for radio wave attenuation and extend the transmission distance. However, in the case of beamforming, the receiving station mainly receives radio waves transmitted intensively from the transmitting station in a specific direction. In other words, since the receiving station receives strong radio waves from a specific direction, it mainly receives radio waves from one path with high reception power. As a result, the spatial multiplexing number remains at 1 (2 in the case of polarization multiplexing), so it is difficult to achieve the effect of spatial diversity, which improves reception quality by receiving the same signal from multiple paths.

On the other hand, there is a method of installing multiple antennas to improve the deterioration of reception quality due to obstruction by obstacles and out-of-line-of-sight. For example, by installing multiple transmitting antennas at different positions, the range of obstruction and out-of-line-of-sight can be reduced, improving reception quality. In addition, installing multiple transmitting antennas can solve the problems in beamforming mentioned above. However, using multiple transmitting antennas increases network costs and makes it difficult to secure a large installation site. Therefore, from the perspective of providing multiple transmission points, it is effective to use reflectors, etc., which are lower cost and have fewer installation size restrictions.

In the past, it was difficult to dynamically control the reflection characteristics of a reflector, but in recent years, metasurface reflectors (dynamic reflectors) that can dynamically control reflection characteristics such as the reflection direction have been developed, making it possible to realize a method of obtaining spatial multiplexing and spatial diversity gain while reducing occlusion and non-line-of-sight ranges using dynamic reflectors (see, for example, non-patent documents 1, 2, and 3).

One method for controlling the reflection characteristics of a dynamic reflector is to change the reflection characteristics by controlling the phase of the radio waves when the dynamic reflector reflects them. For example, a method has been considered in which the phase of the radio waves reflected by a dynamic reflector configured as an array element is changed based on channel information (CSI: Channel State Information) between the transmitting and receiving stations (see, for example, Non-Patent Document 3).

C. Liaskos, A. Tsioliaridou, A. Pitsillides, S. Ioannidis, and I. Akyildiz, "Using any surface to realize a new paradigm for wireless communications," Communications of the ACM, Vol.61, No.11, Nov. 2018. E. Baser, M. D. Renzo, J. D. Rosny, M. Debbah, M-S Alouini, and R. Zhang, "Wireless communications through reconfigurable intelligent surfaces," IEEE Access, Vol.7, Aug. 2019. Q. Wu, and R. Zhang, “Intelligent reflecting surface enhanced wireless network via joint active and passive beamforming,” IEEE transaction on wireless communications, vol.18, no.11, Nov. 2019.

However, while conventional methods based on channel information between transmitting and receiving stations can optimize the characteristics at the receiving station, they require channel information for each array element through which the radio waves pass. For example, if a dynamic reflector is made up of 100 array elements, it is necessary to calculate the amount of phase change based on 100 sets of channel information. In other words, there is an issue that a large overhead is generated in order to obtain the channel information.

In addition, a certain amount of computational resources is required to calculate the amount of phase change for each array element, and it is conceivable that the phase change could be calculated on the wireless base station side. In this case, the wireless base station must be equipped with a new function in order to achieve quality improvement using a dynamic reflector. Furthermore, if the wireless base station and the dynamic reflector are installed in separate locations, a communication means is required to reflect the amount of phase change calculated by the wireless base station in the dynamic reflector, and the dynamic reflector also needs a function for linking with the wireless base station.

A method of reducing overhead can be considered by using the location information of the wireless terminal instead of channel information when calculating the amount of phase change. Furthermore, by having the function of acquiring location information on the dynamic reflector rather than the wireless base station, there is no need to add a new function to the wireless base station, and no need for a means of communication with the dynamic reflector.

However, when controlling a dynamic reflector based on position information, it is necessary to accurately determine the settings for the reflection direction of the dynamic reflector in advance (such as the angle of incidence and angle of reflection). If the settings are inaccurate, or if an error occurs in the reflection direction for some reason while the dynamic reflector is in operation, it will not be able to reflect in the correct direction relative to the position information of the terminal device, making it difficult to perform the expected function.

In view of the above problems, the present invention aims to provide a wireless relay control method and a wireless relay device that can determine the optimal reflection direction setting value according to the position information of a wireless terminal using a discriminator generated by machine learning information that associates the reflection direction setting value with the position information and reception quality information of a wireless terminal.

The wireless relay control method of the present invention is a wireless relay control method for relaying communications between a wireless base station and a wireless terminal using a wireless relay device having a dynamic reflector, wherein the wireless relay device performs a dynamic reflection process in which the phase of the radio waves reflected by the dynamic reflector is controlled based on a setting value including information on the angle of incidence and angle of reflection of the radio waves, and the incident radio waves are reflected in any direction, and a control process in which a discriminator generated by machine learning collects learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and determines the optimal setting value corresponding to the location information of the wireless terminal, and outputs the setting value to the dynamic reflection process.
Further, a wireless relay control method according to the present invention is a wireless relay control method for relaying communication between a wireless base station and a wireless terminal by a wireless relay device having a dynamic reflector, the wireless relay device performing a dynamic reflection process of controlling a phase of a radio wave reflected by the dynamic reflector based on a setting value and reflecting an incident radio wave in an arbitrary direction, and a control process of determining an optimal setting value corresponding to the location information of the wireless terminal by a discriminator generated by machine learning by collecting learning information correlating location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and outputting the setting value to the dynamic reflection process, the information collection phase having a process of outputting the setting value for learning to the dynamic reflection process, and a process of outputting the setting value for learning to the dynamic reflection process. The method includes a process of acquiring information from the wireless terminal, a process of transmitting learning information associating the setting value, the location information, and the reception quality information to an information processing unit inside or outside the wireless relay device, and a process in which the information processing unit records the learning information and performs machine learning, and a process of receiving from the information processing unit a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that results in the best reception quality, and in generating the discriminator, the information processing unit sets the location information of multiple wireless terminals that have the same setting value as a location information group, calculates the center of gravity of all the location information included in the location information group as a representative point, and generates the discriminator by associating one setting value with the location information of the representative point, and in the direction determination phase, a process of discriminating the setting value corresponding to the location information received from the wireless terminal by the discriminator, and setting the setting value discriminated by the discriminator in the dynamic reflection processing.

In addition, the wireless relay device of the present invention is a wireless relay device that relays communications between a wireless base station and a wireless terminal using a dynamic reflector, and is characterized in having a dynamic reflection unit that controls the phase of the radio waves reflected by the dynamic reflector based on a setting value including information on the angle of incidence and angle of reflection of the radio waves, and reflects the incident radio waves in any direction, and a control unit that determines the optimal setting value corresponding to the location information of the wireless terminal using a discriminator generated by machine learning by collecting learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and outputs the setting value to the dynamic reflection unit.
Further, a wireless relay device according to the present invention is a wireless relay device that relays communication between a wireless base station and a wireless terminal using a dynamic reflector, the wireless relay device comprising: a dynamic reflector that controls a phase of a radio wave reflected by the dynamic reflector based on a setting value and reflects an incident radio wave in an arbitrary direction; and a control unit that collects learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, determines the optimal setting value corresponding to the location information of the wireless terminal using a discriminator generated by machine learning, and outputs the setting value to the dynamic reflection unit; and the wireless relay device has an information collection phase and a direction determination phase, and in the information collection phase, the control unit outputs the learning setting value to the dynamic reflection unit, and when the learning setting value is set to the dynamic reflection unit, the control unit outputs the location information of the wireless terminal that communicates with the dynamic reflection unit. and acquiring information about the wireless terminal and the reception quality information from the wireless terminal, outputting learning information associating the setting value, the location information, and the reception quality information to an information processing unit, the information processing unit recording the learning information and performing machine learning, and receiving from the information processing unit a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that provides the best reception quality, wherein in generating the discriminator, the information processing unit sets the location information of a plurality of the wireless terminals having the same setting value as a location information group, calculates a center of gravity of the location information group as a representative point, and generates the discriminator by associating one setting value with the location information of the representative point, and wherein in the direction determination phase, the control unit discriminates the setting value corresponding to the location information received from the wireless terminal by the discriminator, and sets the setting value discriminated by the discriminator to the dynamic reflection unit.

The wireless relay control method and wireless relay device according to the present invention can determine the optimal reflection direction setting value according to the location information of a wireless terminal using a discriminator generated by machine learning information that associates the reflection direction setting value with the location information and reception quality information of a wireless terminal. This reduces the error in the setting value, and makes it possible to control the reflection direction of a dynamic reflector with less overhead than a method that calculates the setting value based on channel information.

1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment of the present invention. FIG. 13 is a diagram showing an example of a reflection direction by a dynamic reflector. FIG. 1 is a diagram illustrating an example of the configuration of a wireless relay device of a comparative example. FIG. 2 is a diagram illustrating an example of the configuration of a wireless relay device according to the present embodiment. FIG. 2 is a diagram illustrating an example of the operation of the entire wireless communication system according to the embodiment. FIG. 11 is a diagram illustrating an example of a process in an information collection phase. FIG. 13 is a diagram illustrating an example of a process in a direction determination phase.

Below, we will explain embodiments of the wireless relay control method and wireless relay device related to the present invention with reference to the drawings.

Figure 1 shows an example of the configuration of a wireless communication system 10 according to this embodiment. In Figure 1, the wireless communication system 10 has a wireless base station 100, a wireless relay device 200, and a wireless terminal 300. In the wireless communication system 10, wireless communication is performed between the wireless base station 100 and the wireless terminal 300 using the wireless relay device 200. For the wireless communication, a high frequency band such as the millimeter wave band is used.

In FIG. 1, a radio base station 100 transmits radio waves, for example, via a transmission beam formed by multiple antennas.

The wireless relay device 200 reflects the radio waves transmitted from the wireless base station 100 in a set reflection direction. The wireless relay device 200 has a dynamic reflector 211 and can dynamically control the reflection direction of the incident radio waves. In the example of FIG. 1, the wireless relay device 200 controls the reflection direction based on the position information of the wireless terminal 300, relays the signal transmitted by the wireless base station 100 to the wireless terminal 300, and relays the signal transmitted by the wireless terminal 300 to the wireless base station 100. Note that the wireless relay device 200 includes a metasurface reflector that uses a metasurface. In this embodiment, in the information collection phase described later, the wireless relay device 200 receives position information and reception quality information from the wireless terminal 300 corresponding to the learning setting value, associates the learning setting value with the position information and reception quality information, and performs machine learning by the information processing unit 240 described later provided inside or outside the wireless relay device 200. The wireless relay device 200 then uses a discriminator generated by machine learning to determine the optimal setting value for the reflection direction in accordance with the position information of the wireless terminal 300 , and controls the reflection direction of the dynamic reflector 211 .

The wireless terminal 300 receives radio waves reflected by the wireless relay device 200. Note that radio waves transmitted from the wireless terminal 300 are similarly reflected by the wireless relay device 200 and received by the wireless base station 100. Here, the wireless terminal 300 has a function of measuring (locating) its own position, and transmits position information indicating its measured position to the wireless relay device 200. Note that in this embodiment, the wireless terminal 300 has a function of measuring reception quality, and transmitting the measured reception quality information and position information to the wireless relay device 200. Note that in this embodiment, the wireless base station 100 does not have any special functions.

In this way, the wireless communication system 10 can form a propagation path between the wireless base station 100 and the wireless terminal 300 via the wireless relay device 200 to perform communication.

Here, in FIG. 1, there is one each of the radio base station 100, radio relay device 200, and radio terminal 300, but this embodiment can also be applied when one or more radio base stations 100 and one or more radio terminals 300 perform wireless communication via one or more radio relay devices 200 whose reflection direction can be controlled.

Figure 2 shows an example of the reflection direction by the dynamic reflector 211. In the example of Figure 2, downlink radio waves transmitted from the wireless base station 100 are reflected by the dynamic reflector 211 and received by the wireless terminal 300. Note that in the case of the uplink, the incident direction and the reflection direction are reversed, and the same can be considered by swapping the incident angle (incident angle) and the reflection angle (reflection angle).

In FIG. 2, the dynamic reflector 211 controls the reflection direction based on the position information notified from the wireless terminal 300. Here, the reflection direction is expressed as an incident angle and a reflection angle with respect to a predetermined reference position, and generally, the direction perpendicular to the surface of the dynamic reflector 211 is the reference direction (0 degrees). The angle between the incident direction of the radio wave transmitted from the wireless base station 100 and the reference direction is the incident angle, and the angle between the reflection direction of the radio wave reflected by the dynamic reflector 211 and the reference direction is the reflection angle. Note that, although FIG. 2 shows an example of the incident angle and reflection angle on a two-dimensional plane, in reality, radio waves incident from any direction in three-dimensional space are reflected in any direction.

[Comparative example wireless relay device 800]
Fig. 3 shows a configuration example of a wireless relay device 800 of a comparative example. The wireless relay device 800 of the comparative example corresponds to the wireless relay device 200 of the wireless communication system 10 shown in Fig. 1. The wireless relay device 800 calculates, for example, an incident angle and a reflection angle based on position information notified from the wireless terminal 300, and controls the reflection direction of the dynamic reflector 211.

In FIG. 3, the wireless relay device 800 has a dynamic reflection unit 210 including a dynamic reflector 211, a direction estimation unit 920, and a communication unit 930.

The dynamic reflector 210 has a dynamic reflector 211 and a reflection direction controller 212, and dynamically controls the reflection direction of radio waves communicated between the radio base station 100 and the radio terminal 300. The dynamic reflector 211 has multiple reflecting elements 211-1 to 211-m (m is an integer of 2 or more), and each reflecting element 211-i (an integer of 1≦i≦m) changes the reflection direction of the incident radio waves according to the respective phases applied by the reflection direction controller 212. Also, instead of applying a phase, the phase converter 213-i described below may be a switch that switches the reflecting element 211-i between active and inactive. In this case, the reflection direction can be controlled by changing the combination of active reflecting elements 211-i.

The reflection direction control unit 212 has phase conversion units 213-1 to 213-m and a phase control unit 214. Each phase conversion unit 213-i applies the phase output from the phase control unit 214 to the respective reflection element 211-i. The phase control unit 214 controls each of the phases that the m phase conversion units 213-i apply to the reflection element 211-i. The magnitude of the controlled phase (phase amount) is determined based on a set value (reflection direction information) notified by the control unit 220.

Based on the location information notified from the wireless terminal 300 via the communication unit 930, the direction estimation unit 920 calculates the angle of incidence at which radio waves are incident from the wireless base station 100 to the dynamic reflector 211 and the angle of reflection at which radio waves are reflected from the dynamic reflector 211 to the wireless terminal 300, and outputs a setting value according to the reflection direction to the dynamic reflection unit 210.

The communication unit 930 has an antenna 931, an RF unit 932, and a signal processing unit 933. The communication unit 930 receives location information notified from the wireless terminal 300.

The RF unit 932 converts the high-frequency signal received by the antenna 931 into a baseband signal.

The signal processing unit 933 demodulates the baseband signal output by the RF unit 932 and outputs the location information transmitted from the wireless terminal 300 to the direction estimation unit 920. The signal processing unit 933 has a function corresponding to any wireless communication system used to acquire location information from the wireless terminal 300.

In this way, the wireless relay device 800 of the comparative example calculates the angle of incidence and the angle of reflection of the dynamic reflector 211 based on the terminal's own position information notified by the wireless terminal 300, and controls the reflection direction.

Here, the direction estimation unit 920 determines the reference direction (0 degree direction) in advance, as described in FIG. 2. The direction estimation unit 920 also has the position information of the dynamic reflector 211 (here, the orthogonal coordinates are [x0, y0, z1]). Then, the reflection angle is calculated using the position information notified from the wireless terminal 300 (here, the orthogonal coordinates are [x1, y1, z1]). In this case, the reflection angle in the horizontal direction can be geometrically calculated as arctan((y1-y0)/(x1-x0)). The reflection angle in the vertical direction can be calculated as arctan((z1-z0)/sqrt((x1-x0) ² +(y1-y0) ² )). Similarly, the incident angle can be calculated using the position information of the wireless base station 100 instead of the position information of the wireless terminal 300.

If there is an estimation error in the angle calculated from the position information, the radio waves cannot be reflected accurately in the direction of the wireless terminal 300 or the wireless base station 100. For example, possible causes of the angle estimation error include a position estimation error of the wireless terminal 300 and the difference between the actual installation angle of the dynamic reflector 211 and the reference direction. In other words, the above calculation method is effective when the direction perpendicular to the surface of the dynamic reflector 211 is accurately set as the reference direction, and if there is an error in the reference direction, the angle of incidence and the angle of reflection will contain errors. As a result, the radio waves will not be reflected in the expected direction.

In contrast, the wireless relay device 200 according to the present embodiment can determine the setting value that provides the best reception quality for the position information of the wireless terminal 300 by machine learning learning information that associates the position information of the wireless terminal 300 and reception quality information for the learning setting value. In other words, in the present embodiment, unlike the comparative example, there is no need to geometrically calculate the angle of incidence and the angle of reflection based on the position information of the wireless terminal 300 (or the wireless base station 100), and the setting value for the reflection direction can be obtained from the position information of the wireless terminal 300 without being affected by errors in the reference angle.

[Wireless relay device 200]
FIG. 4 shows an example of the configuration of the wireless relay device 200 according to this embodiment. The wireless relay device 200 has a dynamic reflection unit 210, a control unit 220, a communication unit 230-1, and a communication unit 230-2. The information processing unit 240 described later may be included inside the wireless relay device 200, or may be provided as a separate device outside. Unlike the wireless relay device 800 of the comparative example, the wireless relay device 200 does not need to geometrically calculate the angle of incidence and the angle of reflection based on the position information of the wireless terminal 300, and can determine the setting value that provides the best reception quality for the position information of the wireless terminal 300 by machine learning learning information that associates the position information of the wireless terminal 300 with the reception quality information for the learning setting value. Furthermore, the wireless relay device 200 according to this embodiment can dynamically control the reflection direction of the radio wave with less overhead than the conventional technology without using channel information for all of the multiple reflecting elements 211-i and without having an advanced signal processing function that processes the channel information for all of the reflecting elements 211-i.

(Dynamic reflection section 210)
The dynamic reflector 210 has basically the same configuration as the block of the same reference numeral in the wireless relay device 800 of the comparative example described in FIG. 3, and includes a plurality of reflecting elements 211-1 to 211-m and a reflection direction controller 212. and dynamically controls the reflection direction of radio waves communicated between the radio base station 100 and the radio terminal 300 (dynamic reflection processing).

The dynamic reflector 211 has multiple reflecting elements 211-1 to 211-m, and can dynamically reflect radio waves communicated between the wireless base station 100 and the wireless terminal 300 in any direction depending on the phase applied to each reflecting element 211-i. Also, instead of applying a phase, the phase conversion unit 213-i described below may be a switch that switches the reflecting elements 211-i between active and inactive. In this case, the reflection direction can be controlled by changing the combination of active reflecting elements 211-i.

The reflection direction control unit 212 has phase conversion units 213-1 to 213-m and a phase control unit 214.

Each phase conversion unit 213-i applies the phase output from the phase control unit 214 to its respective reflection element 211-i.

The phase control unit 214 controls the phases that the m phase conversion units 213-i apply to the reflecting elements 211-i. The magnitude of the controlled phase (phase amount) is determined based on a setting value (reflection direction information) notified by the control unit 220.

In the wireless relay device 200 according to the present embodiment, an example of dynamically controlling the phase of radio waves will be described, but the wireless relay device may be configured to relay radio waves using a repeater having a power amplifier. The wireless relay device 200 may also dynamically control the reflection direction of radio waves at arbitrarily set timing.

(Communication unit 230)
The communication unit 230 has two systems, a communication unit 230-1 and a communication unit 230-2. Note that, although a case where the communication unit 230 has two systems, a communication unit 230-1 and a communication unit 230-2, is described here, the communication unit 230 may have one system and be used in a time-division manner.

The communication unit 230-1 has an antenna 231-1, an RF unit 232-1, and a signal processing unit 233-1. The communication unit 230-1 receives notification information: 1 (first notification information) transmitted from the wireless terminal 300. Here, the notification information: 1 includes, for example, the position information and reception quality information of the wireless terminal 300.

The RF unit 232-1 converts the high-frequency signal received by the antenna 231-1 into a baseband signal.

The signal processing unit 233-1 demodulates the baseband signal output by the RF unit 232-1 and outputs the notification information: 1 transmitted from the wireless terminal 300 to the control unit 220. The signal processing unit 233-1 has a function corresponding to any wireless communication system used to obtain the notification information: 1 from the wireless terminal 300.

The communication unit 230-2 has an antenna 231-2, an RF unit 232-2, and a signal processing unit 233-2. The communication unit 230-2 has a function of transmitting notification information: 2 (second notification information) output by the control unit 220 to the information processing unit 240, and receiving notification information 3 (third notification information) transmitted by the information processing unit 240. Here, notification information: 2 is information (learning information) that associates notification information: 1 (position information and reception quality of the wireless terminal 300) with the setting value of the reflection direction when the reception quality is measured. In addition, notification information: 3 is information of a discriminator created by the information processing unit 240 through machine learning of the learning information. Note that the discriminator is a software processing block (or discrimination table) for discriminating the setting value of the reflection direction that provides the best reception quality from the position information notified from the wireless terminal 300 during operation.

The RF unit 232-2 converts the high-frequency signal received by the antenna 231-2 into a baseband signal and outputs it to the signal processing unit 233-2, and also converts the baseband signal output by the signal processing unit 233-2 into a high-frequency signal and transmits it from the antenna 231-2.

The signal processing unit 233-2 demodulates the baseband signal output by the RF unit 232-2 and outputs notification information: 3 transmitted from the information processing unit 240 to the control unit 220, and also modulates notification information: 2 output by the control unit 220 into a baseband signal and outputs it to the RF unit 232-2. The signal processing unit 233-2 has a function corresponding to any wireless communication system used to notify the information processing unit 240 of notification information: 2 and to obtain notification information: 3 from the information processing unit 240.

In the above explanation, a communication unit 230-1 for receiving notification information: 1 from the wireless terminal 300 and a communication unit 230-2 for transmitting notification information: 2 to the information processing unit 240 and receiving notification information: 3 from the information processing unit 240 are provided separately, but they may also be configured as a single communication unit 230.

In addition, when the information processing unit 240 is installed in the same location as the wireless relay device 200, or when it is mounted on the wireless relay device 200, the connection between the communication unit 230-2 and the information processing unit 240 may be wired rather than wireless.

(Control unit 220)
The control unit 220 has a direction estimation unit 221 and an information transfer unit 222. The control unit 220 executes an information collection phase in which the control unit 220 associates the location information and reception quality notified from the wireless terminal 300 with a learning setting value set in the dynamic reflection unit 210 and notifies the information processing unit 240 of the association, and a direction determination phase in which the control unit 220 determines a setting value of the reflection direction that provides the best reception quality based on a discriminator downloaded from the information processing unit 240 and transmits the setting value to the dynamic reflection unit 210 (control process).

In the direction determination phase, the direction estimation unit 221 determines a setting value for the reflection direction based on notification information: 1 (in this phase, only the position information of the wireless terminal 300 may be used) acquired via the communication unit 230-1 and notification information: 3 (a discriminator that obtains a setting value for the reflection direction from the position information of the wireless terminal 300) downloaded from the information processing unit 240, and outputs the setting value to the dynamic reflection unit 210.

In the information collection phase, the information transfer unit 222 acquires notification information: 1 from the wireless terminal 300 and transmits notification information: 2 to the information processing unit 240. Specifically, the information transfer unit 222 associates the information contained in the notification information: 1 acquired via the communication unit 230-1 (the position information and reception quality of the wireless terminal 300) with the setting value of the reflection direction set by the direction estimation unit 221 in the dynamic reflection unit 210, generates notification information: 2, and transmits it to the information processing unit 240 via the communication unit 230-2.

In this way, the wireless relay device 200 determines the setting value of the reflection direction that provides the best reception quality using a discriminator created by learning from the notification information: 1, which includes at least the position information and reception quality information notified from the wireless terminal 300, and the notification information: 2, which associates the setting value of the reflection direction of the dynamic reflection unit 210. This makes it possible to set the reflection direction in the dynamic reflection unit 210 with high accuracy according to the position of the wireless terminal 300.

Figure 5 shows an example of the operation of the entire wireless communication system 10 according to this embodiment. In Figure 5, blocks with the same reference numerals as in Figures 1 and 4 indicate the same things.

In Figure 5, radio waves (high frequency data signals) transmitted from the radio base station 100 are reflected by the dynamic reflection unit 210 of the radio relay device 200 and received by the radio terminal 300. Note that Figure 5 shows an example of a downlink from the radio base station 100 to the radio terminal 300, but the same is true for an uplink from the radio terminal 300 to the radio base station 100. Each operation from (1) to (7) shown in Figure 5 will be explained below.

Operation (1) The control unit 220 of the wireless relay device 200 outputs learning setting values to the dynamic reflection unit 210.

Operation (2) The wireless terminal 300 measures the reception quality when receiving the data signal of the wireless base station 100 reflected by the dynamic reflection unit 210. Here, the reception quality is, for example, the reception power, SNR, error rate, throughput, and the number of retransmissions. Note that the measurement of the reception quality may be performed using a predetermined known signal or a normal communication signal.

Operation (3) The wireless terminal 300 notifies the wireless relay device 200 of information related to the measured reception quality (reception quality information) and the location information at the time of measuring the reception quality (notification information: 1). The notification information: 1 is transmitted by a communication system different from the communication system between the wireless base station 100 and the wireless terminal 300. For example, Wi-Fi (registered trademark) used in wireless LANs, BLE (Bluetooth (registered trademark) Low Energy), a low-power short-range communication method, D2D (device to device) for device-to-device communication, etc. may be used.

Operation (4) Notification information: 1 transmitted from the wireless terminal 300 is received by the communication unit 230 (communication unit 230-1) of the wireless relay device 200 and output to the control unit 220. The control unit 220 associates the notification information: 1 with the learning setting value set in the dynamic reflection unit 210 in operation (1) (notification information: 2).

Operation (5) The control unit 220 transmits the notification information: 2 from the communication unit 230 (communication unit 230-2) to the information processing unit 240. The information processing unit 240 collects the notification information: 2 as learning information. The notification information: 2 is transmitted by a communication system different from the communication system between the wireless base station 100 and the wireless terminal 300. For example, the use of wireless communication such as Wi-Fi (registered trademark) used in wireless LANs, cellular communication, or wired communication such as optical communication may be used. The information processing unit 240 may also receive the notification information: 1 directly from the wireless terminal 300. In this case, the information processing unit 240 has a function of associating the notification information: 1 received from the wireless terminal 300 with the setting value received from the control unit 220.

Operation (6) The information processing unit 240 performs machine learning using the learning information collected from the control unit 220. The information processing unit 240 then performs machine learning on the learning information that associates the position information of the wireless terminal 300 with the reception quality information for the learning setting values, thereby generating a discriminator as a learning result that discriminates the setting value that provides the best reception quality for the position information of the wireless terminal 300. The information processing unit 240 may be included in the wireless relay device 200 and installed in the same location as the dynamic reflection unit 210, or may be separate from the wireless relay device 200 and installed in a different location from the dynamic reflection unit 210.

Operation (7) The control unit 220 downloads the discriminator from the information processing unit 240 as notification information: 3 via the communication unit 230 (communication unit 230-2).

In this way, in the information collection phase during learning, the wireless relay device 200 according to this embodiment can generate a discriminator that discriminates the setting value that provides the best reception quality for the position information of the wireless terminal 300 by machine learning learning information that associates the position information and reception quality information of the wireless terminal 300 with the learning setting value. Then, in the direction determination phase during operation, the wireless relay device 200 can use the discriminator generated in the learning process to determine the setting value that provides the best reception quality for the position information notified from the wireless terminal 300, and set it in the dynamic reflection unit 210.

Here, the operations from (1) to (5) shown in FIG. 5 may be executed repeatedly. In this case, the learning setting value is switched in sequence, and learning information for a plurality of reflection directions within a predetermined range is collected. The information processing unit 240 performs machine learning on the learning information recorded by collecting data, and generates a discriminator that discriminates the optimal reflection direction setting value corresponding to the position information of the wireless terminal 300. For example, the information processing unit 240 can generate a discriminator that discriminates the combination of the position information of the wireless terminal 300 and the reflection direction setting value that statistically provides the best reception quality. This allows the control unit 220 of the wireless relay device 200 to obtain the optimal reflection direction setting value from the position information of the wireless terminal 300.

Figure 6 shows an example of the processing in the information gathering phase. Note that in Figure 6, the explanation focuses on [Collection Process-1], but the same processing is repeatedly executed from [Collection Process-1] to [Collection Process-n] (n is a positive integer) while sequentially changing the reflection direction. Below, the processing flow of the information gathering phase will be explained in order.

In step S10, the control unit 220 determines the reflection direction for evaluating the reception quality. Here, the same process is performed while switching between multiple reflection directions in a predetermined range from [Collection process-1] to [Collection process-n].

In step S11, the control unit 220 sets a setting value corresponding to the reflection direction for evaluating the reception quality in the dynamic reflection unit 210.

In step S12, the dynamic reflection unit 210 switches the reflection direction of the dynamic reflector 211 based on the setting value set by the control unit 220.

In step S13, the wireless terminal 300 measures the reception quality of the radio waves reflected by the dynamic reflector 211.

In step S14, the wireless terminal 300 transmits notification information: 1, which includes information on the reception quality measured in step S13 (reception quality information) and the location information of the wireless terminal 300 at the time of measurement, to the communication unit 230 (communication unit 230-1). The notification information: 1 received by the communication unit 230-1 is output to the control unit 220.

In step S15, the control unit 220 creates notification information: 2 by associating the reception quality information and location information contained in notification information: 1 with the setting values set in the dynamic reflection unit 210 in step S11.

In step S16, the control unit 220 transmits notification information: 2 from the communication unit 230 (communication unit 230-2) to the information processing unit 240.

In step S17, the information processing unit 240 records the setting values associated with the reception quality information and location information contained in the notification information: 2 as learning information in a storage medium such as a memory.

In this manner, [Collection Process-1] is executed from step S10 to step S17. Then, similar processes are executed from [Collection Process-2] to [Collection Process-n] while changing the reflection direction determined in step S10 and the setting value set in the dynamic reflection unit 210 in step S11. Then, after [Collection Process-n] is executed, the process of step S18 is executed.

In step S18, the information processing unit 240 performs a learning process by machine learning based on the learning information collected by the processes from [collection process-1] to [collection process-n] and stored in the storage medium of the information processing unit 240. Then, the information processing unit 240 generates a discriminator by machine learning that discriminates the setting value that provides the best reception quality for the position information of the wireless terminal 300.

Figure 7 shows an example of processing in the direction determination phase. Note that Figure 7 is executed following the information collection phase described in Figure 6. Below, the processing following the processing of step S18 in the information collection phase will be explained in order.

In step S19, the information processing unit 240 transmits notification information: 3 including the discriminator generated in step S18 to the communication unit 230 (communication unit 230-2), and the notification information: 3 is output from the communication unit 230 to the control unit 220. Here, pre-processing may be performed to reduce the overhead of the notification information: 3. For example, the position information of multiple wireless terminals 300 with the same reflection direction setting value may be treated as a position information group, the center of gravity of all the position information included in the position information group may be calculated as a representative point, and a discriminator may be generated by associating one setting value with the position information of the representative point.

In step S20, the control unit 220 records the discriminator generated by the information processing unit 240 in a storage medium such as an internal memory.

Through the processing up to this point, the control unit 220 of the wireless relay device 200 is able to determine the reflection direction that provides the best reception quality for the location information notified by the wireless terminal 300, and the wireless relay device 200 performs direction determination processing during operation as follows.

In step S21, the wireless terminal 300 transmits notification information: 1 including at least its own location information to the communication unit 230 (communication unit 230-1), similar to step S14 described in FIG. 6. The notification information: 1 received by the communication unit 230-1 is output to the control unit 220. Note that the notification information: 1 may include reception quality information, similar to the information collection phase, or may only include location information. Furthermore, the notification information: 1 may include an identification number of the wireless terminal 300 (such as a serial number or a MAC (Media Access Control) address). This makes it possible to manage each wireless terminal 300 individually.

Here, steps S22, S23, and S24 shown in FIG. 7 may not be executed, but if information collection is performed during the direction determination phase, steps S22, S23, and S24 may be executed. This allows the information processing unit 240 to collect learning information even during operation, so that a more accurate discriminator can be generated. In this case, the information processing unit 240 may update the discriminator recorded in the control unit 220 periodically or when a certain amount of learning information has been accumulated. The update may be performed by notifying the control unit 220 that a new discriminator has been generated from the information processing unit 240 side, or by polling periodically from the control unit 220 side. Note that steps S22, S23, and S24 correspond to steps S15, S16, and S17 in FIG. 6, respectively. In either case, the next step S25 is executed in the direction determination phase.

In step S25, the control unit 220 determines the reflection direction corresponding to the position information contained in the notification information: 1 notified from the wireless terminal 300 in step S21 using the discriminator acquired in step S20, and determines the reflection direction.

In step S26, the control unit 220 sets a setting value corresponding to the reflection direction determined in step S25 in the dynamic reflection unit 210.

In step S27, the dynamic reflection unit 210 switches the reflection direction of the dynamic reflector 211 based on the setting value set by the control unit 220.

In this way, in the information collection phase during learning, the wireless relay device 200 according to this embodiment can generate a discriminator that discriminates the setting value that provides the best reception quality for the position information of the wireless terminal 300 by machine learning learning information that associates the position information and reception quality information of the wireless terminal 300 with the learning setting value. Then, in the direction determination phase during operation, the wireless relay device 200 can use the discriminator generated in the learning process to determine the setting value that provides the best reception quality for the position information notified from the wireless terminal 300, and set it in the dynamic reflection unit 210.

As described above in the embodiments, the wireless relay control method and wireless relay device according to the present invention can determine the optimal reflection direction setting value according to the position information of the wireless terminal using a discriminator generated by machine learning information that associates the reflection direction setting value with the position information and reception quality information of the wireless terminal. This reduces the error in the setting value, and makes it possible to control the reflection direction of the dynamic reflector with less overhead than a method that calculates the setting value based on channel information.

10: Wireless communication system; 100: Wireless base station; 200, 800: Wireless relay device; 210: Dynamic reflector; 211: Dynamic reflector; 211-i: Reflection element; 212: Reflection direction control unit; 213-i: Phase conversion unit; 214: Phase control unit; 220: Control unit; 221, 920: Direction estimation unit; 222: Information transfer unit; 230, 230-1, 230-2, 930: Communication unit; 231-1, 231-2, 931: Antenna; 232-1, 232-2, 932: RF unit; 233-1, 233-2, 933: Signal processing unit; 240: Information processing unit; 300: Wireless terminal

Claims (12)

A wireless relay control method for relaying communication between a wireless base station and a wireless terminal by a wireless relay device having a dynamic reflector, comprising the steps of:
The wireless relay device includes:
a dynamic reflection process for controlling a phase of the radio wave reflected by the dynamic reflector based on a set value including information on an incident angle and a reflection angle of the radio wave , and reflecting the incident radio wave in an arbitrary direction;
a control process of determining the optimal setting value corresponding to the location information of the wireless terminal using a discriminator generated by machine learning by collecting learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and outputting the setting value to the dynamic reflection process. 2. The wireless relay control method according to claim 1,
The method includes an information gathering phase and a direction determination phase,
In the information gathering phase,
A process of outputting the setting value for learning to the dynamic reflection process;
A process of acquiring, from the wireless terminal, the position information and the reception quality information of the wireless terminal that communicates when the setting value for learning is set by the dynamic reflection process;
a process of transmitting learning information, which associates the set value, the location information, and the reception quality information, to an information processing unit inside or outside the wireless relay device;
The information processing unit records the learning information and performs machine learning, and a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that provides the best reception quality is received from the information processing unit;
In the direction determination phase,
a process of determining, by the determiner, the setting value corresponding to the location information received from the wireless terminal;
The setting value determined by the discriminator is set in the dynamic reflection processing. 3. The wireless relay control method according to claim 2,
the information processing unit also acquires the learning information, performs machine learning, and updates the discriminator during the direction determination phase. 4. The wireless relay control method according to claim 2, further comprising:
the information processing unit regards the location information of a plurality of the wireless terminals having the same setting value as a location information group, calculates a center of gravity of all the location information included in the location information group as a representative point, and associates one of the setting values with the location information of the representative point to generate the discriminator. A wireless relay device that relays communication between a wireless base station and a wireless terminal using a dynamic reflector,
a dynamic reflection unit that controls a phase of the radio wave reflected by the dynamic reflector based on a set value including information on an incident angle and a reflection angle of the radio wave , and reflects the incident radio wave in an arbitrary direction;
a control unit that determines the optimal setting value corresponding to the location information of the wireless terminal using a discriminator generated by machine learning by collecting learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and outputs the setting value to the dynamic reflection unit. 6. The wireless relay device according to claim 5,
The method includes an information gathering phase and a direction determination phase,
In the information gathering phase,
The control unit is
outputting the setting value for learning to the dynamic reflection unit;
acquiring, from the wireless terminal, the position information and the reception quality information of the wireless terminal that communicates when the setting value for learning is set in the dynamic reflection unit;
outputting learning information that associates the setting value, the location information, and the reception quality information to an information processing unit;
The information processing unit records the learning information and performs machine learning, and receives from the information processing unit a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that provides the best reception quality;
In the direction determination phase,
The control unit is
determining, by the discriminator, the setting value corresponding to the location information received from the wireless terminal;
The setting value determined by the discriminator is set in the dynamic reflection unit. 7. The wireless relay device according to claim 6,
The wireless relay device, wherein the information processing unit acquires the learning information, performs machine learning, and updates the discriminator even during the direction determination phase. 8. The wireless relay device according to claim 6,
The wireless relay device is characterized in that the information processing unit treats the location information of multiple wireless terminals that have the same setting value as a location information group, calculates a center of gravity of the location information group as a representative point, and associates one of the setting values with the location information of the representative point to generate the discriminator. A wireless relay control method for relaying communication between a wireless base station and a wireless terminal by a wireless relay device having a dynamic reflector, comprising the steps of:
The wireless relay device includes:
A dynamic reflection process that controls the phase of the radio waves reflected by the dynamic reflector based on a set value and reflects the incident radio waves in an arbitrary direction;
a control process of determining an optimal setting value corresponding to the position information of the wireless terminal by a discriminator generated by machine learning by collecting learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measured the reception quality information, and outputting the setting value to the dynamic reflection process;
Do the following:
The method includes an information gathering phase and a direction determination phase,
In the information gathering phase,
A process of outputting the setting value for learning to the dynamic reflection process;
A process of acquiring, from the wireless terminal, the position information and the reception quality information of the wireless terminal that communicates when the setting value for learning is set by the dynamic reflection process;
a process of transmitting learning information, which associates the set value, the location information, and the reception quality information, to an information processing unit inside or outside the wireless relay device;
The information processing unit records the learning information and performs machine learning, and a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that provides the best reception quality is received from the information processing unit;
In generating the discriminator, the information processing unit sets the location information of the plurality of wireless terminals having the same setting value as a location information group, calculates a center of gravity of all the location information included in the location information group as a representative point, and generates the discriminator by associating one of the setting values with the location information of the representative point;
In the direction determination phase,
a process of determining, by the determiner, the setting value corresponding to the location information received from the wireless terminal;
The set value determined by the discriminator is set in the dynamic reflection processing.
A radio relay control method comprising: 10. The wireless relay control method according to claim 9,
The information processing unit also acquires the learning information, performs machine learning, and updates the classifier during the direction determination phase.
A radio relay control method comprising: A wireless relay device that relays communication between a wireless base station and a wireless terminal using a dynamic reflector,
a dynamic reflection unit that controls a phase of the radio wave reflected by the dynamic reflection plate based on a set value and reflects the incident radio wave in an arbitrary direction;
a control unit that determines an optimal setting value corresponding to the location information of the wireless terminal by a discriminator generated by machine learning by collecting learning information that associates location information and reception quality information received from the wireless terminal with the setting value when the wireless terminal measures the reception quality information, and outputs the setting value to the dynamic reflection unit;
having
The method includes an information gathering phase and a direction determination phase,
In the information gathering phase,
The control unit is
outputting the setting value for learning to the dynamic reflection unit;
acquiring, from the wireless terminal, the position information and the reception quality information of the wireless terminal that communicates when the setting value for learning is set in the dynamic reflection unit;
outputting learning information that associates the setting value, the location information, and the reception quality information to an information processing unit;
The information processing unit records the learning information and performs machine learning, and receives from the information processing unit a discriminator that discriminates a combination of the setting value and the location information of the wireless terminal that provides the best reception quality;
In generating the discriminator, the information processing unit regards the position information of a plurality of the wireless terminals having the same setting value as a position information group, calculates a center of gravity of the position information group as a representative point, and generates the discriminator by associating one of the setting values with the position information of the representative point;
In the direction determination phase,
The control unit is
determining, by the discriminator, the setting value corresponding to the location information received from the wireless terminal;
The set value determined by the determiner is set in the dynamic reflection section.
1. A wireless relay device comprising: The wireless relay device according to claim 11,
The information processing unit also acquires the learning information, performs machine learning, and updates the classifier during the direction determination phase.
1. A wireless relay device comprising:

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