Method, system, and program

Abstract

The present invention reduces overhead in reporting a measurement result for one or more beams and suppresses a decrease in the accuracy of selecting an optimum beam. A reception-side device performs: repeatedly measuring one or more beams transmitted from one or more transmission points; acquiring, from values obtained through measurements performed a prescribed number of times for each of the one or more beams, first information which reflects a variation in reception signal strength during a measurement period for the prescribed number of times and which has a data size smaller than that of the values obtained through the measurements performed the prescribed number of times for each of the one or more beams; and transmitting the first information to a transmission-side device. The transmission-side device performs beam management on the basis of the first information.

Description

Method, system, and program

[0001] The present disclosure relates to beam management in wireless communications.

[0002] In wireless communications such as the 5th Generation Mobile Communication System (5G), distributed MIMO (Multi-Input Multi-Output) is proposed, in which one or more antennas near a mobile station are selected from among multiple antennas distributed within the communication area of ​​a single base station for communication. Distributed MIMO reduces blind spots in radio waves and reduces the impact of obstructions by distributing antennas.

[0003] 3GPP TR 38.802 V14.2.0 (2017-09)3GPP TS 38.214 V18.2.0 (2024-03)3GPP TS 38.213 V18.2.0 (2024-03)

[0004] When multiple transmit antennas are used, such as in distributed MIMO, a mobile station communicates using a beam designated by a network-side control device. The radio wave strength of a radio signal transmitted by a beam changes over time due to the movement of the mobile station and changes in the surrounding environment. Therefore, the mobile station periodically measures the received signal strength of multiple beams, including a communication beam, for each radio frame or slot, and reports the measurement results to the network-side control device. An example of the received signal strength of a beam is RSRP (Reference Signal Received Power), which is the received power using a reference signal. Other information reported by the mobile station includes, for example, strength measurement using SSB (Synchronization Signal Blocks) and signal-to-interference-plus-noise power ratio (SINR) using ZP-CSI-RS (Zero-Power Channel State Information Reference Signal). A reference signal is a signal intended to measure the radio wave propagation environment. Based on the measurement results from the mobile station, the control device reselects a beam pattern for each of the multiple beams, including the communication beam, that is more appropriate in response to changes in the movement of the mobile station and the surrounding environment. This allows the mobile station to be provided with a communication beam that can provide better quality wireless communication depending on the movement of the mobile station and changes in the surrounding environment. A beam pattern is simply the direction and width of a beam.

[0005] However, when a mobile station is stationary, the radio wave reception environment fluctuates little, and the quality of wireless communication using communication beams is unlikely to fluctuate significantly. Therefore, periodic reporting of received signal strengths for multiple beams from the mobile station can result in overhead. On the other hand, simply reducing the frequency of reports would result in the control device being notified of the latest measured values ​​of received signal strength, but would not convey to the control device, for example, the probabilistic behavior of received signal strength and the temporal and spatial change trends of the beams. As a result, when the control device selects a beam pattern for each of multiple new beams based on reports from the mobile station, it may not be able to eliminate the influence of probabilistically fluctuating received signal strength or consider the temporal and spatial change trends of the beams, resulting in the inability to select the optimal beam for data communication.

[0006] One aspect of the present disclosure is to provide a method, system, and program that can reduce overhead in reporting measurement results for one or more beams and suppress a decrease in accuracy in selecting the optimal beam.

[0007] One aspect of the present disclosure is a method in which a receiving device repeatedly measures one or more beams transmitted from one or more transmission points, obtains first information from a predetermined number of measurement values ​​for each of the one or more beams, which reflects fluctuations in received signal strength during the predetermined number of measurement periods, and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams, and transmits the first information to a transmitting device, wherein the first information is used by the transmitting device for beam management.

[0008] Another aspect of the present disclosure is a system including a receiving device and a transmitting device, wherein the receiving device performs the following: repeatedly measures one or more beams transmitted from one or more transmission points; acquires, from a predetermined number of measurement values ​​for each of the one or more beams, first information that reflects fluctuations in received signal strength during the predetermined number of measurement periods and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams; and transmits the first information to the transmitting device; and the transmitting device performs beam management based on the first information.

[0009] Another aspect of the present disclosure is a program for causing a computer to perform the following: repeatedly measuring one or more beams transmitted from one or more transmission points; obtaining first information that reflects fluctuations in received signal strength during a predetermined number of measurement periods from a predetermined number of measurement values ​​for each of the one or more beams and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams; and transmitting the first information to a transmitting device, wherein the first information is used by the transmitting device for beam management.

[0010] According to one aspect of the present disclosure, a method, system, and program can be provided that can reduce overhead in reporting measurement results for one or more beams and suppress a decrease in accuracy in selecting the optimal beam.

[0011] FIG. 1 is a diagram illustrating an example of the system configuration of a communication system according to the first embodiment. FIG. 2 is a diagram illustrating an example of the hardware configuration of a mobile station. FIG. 3 is a diagram illustrating an example of the functional configuration of a mobile station. FIG. 4 is a diagram illustrating an example of the functional configuration of a control device. FIG. 5 is a diagram illustrating an arrangement of RSRP measurement values ​​of a beam set in a mobile station. FIG. 6 is an example of a flowchart of a process for reporting RSRP measurement results of a beam set in a mobile station. FIG. 7 is an example of a flowchart of beam management process in a control device. FIG. 8 is a diagram illustrating an example of a sequence of beam management processing in a communication system. FIG. 9 is an example of a flowchart of a process for reporting RSRP measurement results of a beam set in a mobile station according to a first modification of the first embodiment. FIG. 10 is an example of a flowchart of a process for reporting RSRP measurement results of a beam set in a mobile station according to a fourth modification of the first embodiment. FIG. 11 is a diagram illustrating an example of quantization of RSRP measurement values ​​of a beam set. FIG. 12 is a diagram illustrating an example of encoding of RSRP measurement values ​​of a beam set after quantization. Fig. 13 is a diagram showing an example of encoding of RSRP measurement values ​​of a beam set after quantization. Fig. 14 is an example of a flowchart of a report data creation process of a mobile station in the second embodiment. Fig. 15 is an example of a flowchart of a beam set selection process of a control device in the second embodiment. Fig. 16 is a diagram showing an example of a method for selecting a beam to be reported. Fig. 17 is a diagram showing an example of a method for selecting a beam to be reported.

[0012] One aspect of the present disclosure is a method in which a receiving device repeatedly measures one or more beams transmitted from one or more transmission points, acquires first information, which reflects fluctuations in received signal strength during a predetermined number of measurement periods from a predetermined number of measurement values ​​for each of the one or more beams and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams, and transmits the first information to a transmitting device. The first information is used by the transmitting device for beam management.

[0013] In the downlink direction from a base station to a terminal station, for example, the receiving device is a terminal station, and the transmitting device is a base station or a control device that controls the base station. In the uplink direction from a terminal station to a base station, for example, the receiving device is a base station or a control device that controls the base station, and the transmitting device is a terminal station. A relay station that relays wireless communication between a base station and a terminal station may be included in either the receiving device or the transmitting device in both the downlink direction and the uplink direction. The terminal station is, for example, a mobile station of a user terminal such as a smartphone, a tablet terminal, or an in-vehicle device. However, the present invention is not limited to this, and the terminal station may also be a stationary terminal that does not move.

[0014] The receiving device measures the received signal strength indicator (RSSI) or the received signal power (RSRP) of a reference signal for one or more beams. The measurement of one or more beams is performed, for example, at a predetermined cycle or whenever a predetermined event occurs. The transmission point is, for example, a base station, a relay station, a terminal station, or an antenna provided therein. The number of measurements to be reported (predetermined number of times) is two or more. Note that the measurements for one or more beams are not limited to RSSI and RSRP, and may also be, for example, RSRQ (Reference Signal Received Quality) and SINR.

[0015] In one aspect of the present disclosure, a predetermined number of measurement results for one or more beams are processed into first information having a smaller data size than the predetermined number of measurement values ​​for the one or more beams and transmitted. This reduces the frequency of reporting measurement results for one or more beams compared to reports at a predetermined interval and reduces the data size of each report, thereby reducing overhead. Furthermore, since the first information reflects fluctuations in received signal strength during a predetermined number of measurement periods, the receiving device can convey to the transmitting device the temporal and spatial change trends and statistics of the beams. Furthermore, by the transmitting device using the first information to perform beam management, probabilistic fluctuation factors of received signal strength, as well as the temporal and spatial change trends and statistics of the beams, are taken into consideration, thereby improving the communication quality of the provided beams.

[0016] In one aspect of the present disclosure, the receiving device may acquire, as the first information, a moving average of a predetermined number of measurements obtained for each of one or more beams, thereby enabling the first information to more strongly reflect the real-time state of the radio wave reception environment at the location of the receiving device.

[0017] The receiving device may also obtain a moving average by multiplying the most recent measurement value by a first coefficient and adding the result of multiplying the moving average of the measurement values ​​from the first measurement to the previous measurement by a value obtained by subtracting the first coefficient from 1. The first coefficient may be a value greater than 0 and less than 1, and may be based on the moving speed and the frequency used by the receiving device. This allows newer measurement values ​​to have a greater influence on the first information. Because the radio wave reception environment changes from moment to moment, assigning a greater weight to more recent measurement values ​​can increase the likelihood that a new beam selected based on the first information is a beam that provides better quality communication at the location of the receiving device. The receiving device does not need to store a predetermined number of measurement values ​​for each of one or more beams, but only needs to store a moving average of the measurement values ​​from the first measurement to the most recent measurement, thereby conserving memory in the receiving device.

[0018] Furthermore, the number of measurements to be reported (predetermined number of measurements) may be the number of measurements corresponding to a moving average window. The moving average window may be based on the moving speed and the frequency used by the receiving device. Since the moving speed and the frequency used by the receiving device are among the factors that affect the radio wave reception environment of the receiving device, by taking these factors into consideration, the length of the moving average window can be set to fully take into account the probabilistic behavior of radio waves.

[0019] The receiving device may further determine, based on the moving speed and frequency of the receiving device, whether to use a first method for acquiring a moving average by calculating a moving average of measurement values ​​for a number of measurements corresponding to a moving average window, or a second method for acquiring a moving average by multiplying the most recent measurement value by a first coefficient and adding a value obtained by multiplying the moving average of measurement values ​​from the first measurement to the previous measurement by a value obtained by subtracting the first coefficient from 1. The second method only requires storing the moving average of measurement values ​​from the first measurement to the most recent measurement, thereby saving memory in the receiving device. By determining whether to acquire the first information using the first method or the second method based on the moving speed and frequency of the receiving device, memory resources of the receiving device can be used efficiently.

[0020] In one aspect of the present disclosure, the receiving device may convert a predetermined number of measurement values ​​for each of the one or more beams into one of a predetermined number of classes and encode the converted measurement values ​​for each of the one or more beams using a predetermined encoding method to obtain first information. The encoding method may be, for example, run-length encoding. The transmitting device may decode the first information into the converted measurement values ​​for each of the one or more beams and perform beam management based on the converted measurement values ​​for each of the one or more beams. This allows the receiving device to notify the transmitting device of fluctuations in received signal strength over a predetermined number of measurement periods in a form that is closer to the actual measurement value.

[0021] Furthermore, the receiving device may acquire the first information by reading the converted measurement values ​​for each of the one or more beams in a predetermined order in a first reading order in which the converted measurement values ​​are read in chronological order. In this case, the size of the first information can be made smaller as the correlation in the time direction between the received signal strengths for a predetermined number of times for the one or more beams becomes stronger.

[0022] Furthermore, the receiving device may acquire the first information in a predetermined order for each of the one or more beams, starting with reading the converted measurement values ​​for the first beam in chronological order and reading the measurement values ​​for the nth beam in the reverse order of that for the (n-1)th beam. n is a variable indicating the beam and takes a value from 1 to the number of beams. In this case, the stronger the correlation in the time direction and the space direction between the received signal intensities for a predetermined number of times for the one or more beam patterns, the smaller the size of the first information can be.

[0023] Furthermore, the receiving device may acquire the first information by encoding a predetermined number of measurement values ​​for each of one or more beams using a predetermined encoding method in a reading order that results in a smaller data size after encoding out of the two reading orders. In this case, the receiving device may transmit the first information and information on the adopted reading order to the transmitting device. This makes it possible to further reduce the data size of the first information.

[0024] Furthermore, the receiving device may acquire the first information by encoding a predetermined number of measurement values ​​for each of a predetermined number of beams whose most recent measurement values ​​are the top of the predetermined number of measurement values ​​using a predetermined encoding method. Alternatively, the receiving device may acquire the first information by encoding a predetermined number of measurement values ​​for each of a predetermined number of beams whose statistical values ​​are the top of the predetermined number of measurement values ​​using a predetermined encoding method. Examples of statistical values ​​include an average value, a median value, a standard deviation value, etc. This allows the data size of the first information to be further reduced.

[0025] Another aspect of the present disclosure can be specified as a system including the receiving device and the transmitting device, and also as a receiving device that executes the processing of the method.

[0026] Another aspect can also be specified as a program for causing a receiving device and a transmitting device to execute the method, and a computer-readable, non-transitory storage medium on which the program is recorded.

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

[0028] First Embodiment Fig. 1 is a diagram showing an example of the system configuration of a communication system 100 according to a first embodiment. The communication system 100 is a distributed MIMO system including a mobile station 1, a control device 2, and a plurality of distributed base stations. The control device 2 is a device on a core network to which the distributed base stations are connected. However, it is also possible to consider the control device 2 as the core network itself or a system included in the core network. The core network includes, for example, an optical fiber network. The control device 2 controls the distributed base stations and the mobile station 1.

[0029] A distributed base station, together with other distributed base stations in the same communication area, provides a radio access network to mobile stations 1 located within the communication area. The three distributed base stations shown in Fig. 1 are assumed to be located within the same communication area. Each of the distributed base stations is connected to a control device 2.

[0030] The distributed base station is equipped with an antenna that can form multiple beam patterns. The antenna equipped in the distributed base station is, for example, an adaptive array antenna. An adaptive array antenna is an array antenna in which multiple antenna elements are arranged. An adaptive array antenna can adaptively control the weighting of each antenna element according to the radio wave propagation environment, and electrically change the beam pattern. The beam pattern can also be said to be the directivity of the beam formed by the adaptive array antenna. The beam pattern of the distributed base station is controlled by the control device 2. Note that the distributed base station may be equipped with one antenna or multiple antennas.

[0031] The mobile station 1 is, for example, a terminal station such as a smartphone, a tablet terminal, a wearable terminal, or an in-vehicle data communication device. However, the present invention is not limited to this, and the mobile station 1 may be a stationary terminal device. The mobile station 1 may also be a relay station that relays wireless communication between a distributed base station and a terminal station. The relay station may be, for example, a small base station, a mobile base station, an in-vehicle device, or a smartphone. In the first embodiment, the mobile station 1 also includes multiple antennas. However, the present invention is not limited to this, and the mobile station 1 may include a single antenna.

[0032] The mobile station 1 receives designation of multiple beams, including a data communication beam and a measurement beam, from the control device 2, and measures the received signal strength of a reference signal for the multiple beams at a predetermined period. In the first embodiment, when a reporting condition is satisfied, the mobile station 1 obtains a moving average of a predetermined number of measurement values ​​for each of the multiple beams and reports the moving average to the control device 2. This reduces the frequency of reporting the received signal strength of the multiple beams from the mobile station 1 to the control device 2, reduces the data size in one report, and reduces overhead.

[0033] The example shown in FIG. 1 includes three transmission points: distributed base stations RU#1, RU#2, and RU#3. Three beams, b0, b1, and b2, are transmitted from distributed base station RU#1. Distributed base station RU#1 is also represented by transmission points m_(0), m_(1), and m_(2) of beams b0, b1, and b2. Characters in parentheses following the underscore are indicated as subscripts in the figure. Two beams, b3 and b4, are transmitted from distributed base station RU#2. Two beams, b5 and b6, are transmitted from distributed base station RU#3. Hereinafter, when reporting data from mobile station 1 is described, the configuration shown in FIG. 1 is assumed. Mobile station 1 is an example of a "receiving device." Control device 2 is an example of a "transmitting device."

[0034] 2 is a diagram illustrating an example of the hardware configuration of the mobile station 1. The mobile station 1 includes a CPU 101, a main memory device 102, an external memory device 103, an output device 104, an operation device 105, a wireless communication device 106, and an antenna 107. The CPU 101 is also referred to as a processor. The CPU 101 is not limited to a single processor, and may have a multi-processor configuration. In addition to the CPU 101, a graphics processing unit (GPU), a digital signal processor (DSP), and the like may also be included. The CPU 101 may also cooperate with a hardware circuit such as a field programmable gate array (FPGA).

[0035] The CPU 101 executes a computer program executablely deployed in the main memory device 102 to provide processing for the mobile station 1. The main memory device 102 stores the computer program executed by the CPU 101, data processed by the CPU 101, etc. The main memory device 102 is, for example, a dynamic random access memory (DRAM), a static random access memory (SRAM), a read only memory (ROM), etc. Furthermore, the external memory device 103 is used as a storage area supporting the main memory device 102, and stores the computer program executed by the CPU 101, data processed by the CPU 101, etc. The external memory device 103 is, for example, a hard disk drive, a solid state drive (SSD), etc. Furthermore, a drive device for a removable storage medium may be connected to the mobile station 1. The removable storage medium is, for example, a Blu-ray disc, a digital versatile disc (DVD), a compact disc (CD), a flash memory card, etc. The CPU 101 is an example of a "control unit" of a "mobile station."

[0036] The output device 104 is, for example, a display device such as a liquid crystal display or an electroluminescence panel. However, the output device 104 may also include a speaker or other device for outputting sound. The operation device 105 is, for example, a touch panel with a touch sensor superimposed on a display. The wireless communication device 106 is connected to an antenna 107, and connects to a wireless access network via the antenna 107 using a mobile wireless communication method such as 5G, and receives wireless signals from a distributed base station. The wireless communication device 106 is also connected to the control device 2 on the control plane. Note that the hardware configuration of the mobile station 1 is not limited to that shown in FIG. 2 .

[0037] The control device 2 includes a CPU, a main memory device, an external memory device, an output device, an operation device, and a communication device. The CPU, main memory device, external memory device, output device, and operation device of the control device 2 are similar to the CPU 101, main memory device 102, external memory device 103, output device 104, and operation device 105. The communication device of the control device 2 communicates with a distributed base station and an external network such as the Internet via optical fiber, for example. The communication device of the control device 2 may be a single device or a combination of multiple devices.

[0038] 3 is a diagram showing an example of the functional configuration of the mobile station 1. The functional configuration of the mobile station 1 includes a control unit 11, a measurement unit 12, and a measurement result storage unit 13. The functions of the control unit 11, the measurement unit 12, and the measurement result storage unit 13 are achieved by the CPU 101 executing a predetermined program.

[0039] The control unit 11 receives designation of data communication beams and measurement beams from the control device 2. The control unit 11 instructs the measurement unit 12 to start measuring the received signal strength (RSRP) of the reference signal for each of the data communication beams and measurement beams at a predetermined period. Hereinafter, a set of data communication beams and measurement beams is referred to as a beam set. One or more data communication beams may be included in a beam set. A measurement beam is a beam pattern for measuring received signal strength, etc., in preparation for updating the data communication beam in response to a deterioration in communication quality. A beam set may include multiple measurement beams. A beam set may include, for example, at least one measurement beam from each transmission point within the communication area of ​​a central base station. However, the method for selecting measurement beams included in a beam set is not limited to this. Hereinafter, the measurement, measurement value, and measurement result of the received signal strength of the reference signal for each beam included in a beam set will be simply referred to as the measurement, measurement value, and measurement result of the RSRP of the beam set, respectively. In addition, the measured value of the received signal strength of the reference signal for each beam included in the beam set may simply be referred to as the RSRP of the beam set.

[0040] When the control unit 11 receives the measurement value of the RSRP of the beam set from the measurement unit 12, it determines whether or not the reporting conditions are satisfied. The reporting conditions are, for example, that one or more of the following is satisfied: the RSRP of the data communication beam is less than a predetermined threshold, the RSRP of the measurement beam is equal to or greater than a predetermined threshold, and there is a measurement beam with a higher RSRP than the data communication beam. However, the reporting conditions are not limited to these.

[0041] The control unit 11 reports to the control device 2 when the reporting conditions are met. The report data to the control device 2 includes the RSRP measurement results (RSRP Report) for each beam included in the beam set. If the reporting conditions are not met, the control unit 11 does not report to the control device 2. The control unit 11 calculates the moving average of the measurement values ​​for a predetermined number of times for each beam included in the beam set, and transmits this to the control device 2 as the measurement result of the RSRP of the beam set. Details of how to calculate the moving average of the measurement values ​​will be described later.

[0042] When the control unit 11 receives a new beam set from the control device 2, it instructs the measurement unit 12 to update the target of RSRP measurement to the new beam set. Then, it determines whether or not to report the RSRP measurement results of the new beam set.

[0043] The measurement unit 12 starts measuring the RSRP for each beam included in the beam set at a predetermined period in accordance with instructions from the control unit 11. The RSRP measurement period is, for example, 0.125 ms, which is a typical 5G slot time length. However, the RSRP measurement period is not limited to this. The measurement unit 12 outputs the measured value of the RSRP of the beam set to the control unit 11.

[0044] The measurement result memory unit 13 is created in a memory area of ​​the main memory device 102. The measurement result memory unit 13 stores the measured values ​​of the RSRP of the beam set. The measured values ​​of the RSRP of the beam set are stored by the control unit 11 each time a measurement is performed. In addition, in the measurement result memory unit 13, if the total data size of the stored measured values ​​of the RSRP of the beam set exceeds a predetermined threshold, the oldest data is deleted. In addition, when a new beam set is received from the control device 2 or a beam selection procedure is executed and the beam set is updated, all stored data in the measurement result memory unit 13 is deleted, i.e., refreshed, by the control unit 11. Note that the functional configuration of the mobile station 1 is not limited to the example shown in Figure 3.

[0045] 4 is a diagram showing an example of the functional configuration of the control device 2. The control device 2 includes, as its functional configuration, a control unit 21. The functions of the control unit 2 are achieved by the CPU executing a predetermined program.

[0046] The control unit 21 determines a beam set, for example, through a beam selection procedure with the mobile station 1, and notifies the mobile station 1 of the beam set. The beam selection procedure is a procedure disclosed in the 3GPP standard in which the angular resolution of the beam is narrowed down in order from low to high, and the optimum beam is selected for the mobile station 1. However, the method for determining the beam set is not limited to the beam selection procedure.

[0047] The control unit 21 receives notification from the mobile station 1 that it is necessary to report the measurement results of the beam set, and provides the mobile station 1 with a communication opportunity for reporting. The control unit 21 receives a report from the mobile station 1 using the communication opportunity. When the control unit 21 receives report data from the mobile station 1, it determines whether or not to update the beam set based on the measurement results of the RSRP of the beam set included in the report data. The conditions for determining whether or not to update the beam set may be the same as or different from the reporting conditions of the mobile station 1. If it is decided to update the beam set, the control unit 21 selects a new beam set. A new beam set is, for example, a beam set in which at least one of one or more beams from one or more transmission points has been changed to a new beam pattern, and / or in which the data communication beam has been changed to a different beam pattern or a beam from a different transmission point.

[0048] The control unit 21 notifies the mobile station 1 of the new beam set. In the first embodiment, the mobile station 1 reports the moving average value of the RSRP for a predetermined number of measurements as the measurement result of the RSRP of the beam set, so the control unit 21 selects a new beam set based on the moving average value of the RSRP of each beam included in the beam set. The method of selecting a beam set based on the moving average value may be, for example, the implementation of a beam selection procedure specified in the 3GPP standard or any other existing method. Note that the functional configuration of the control device 2 is not limited to the example shown in Figure 4.

[0049] <Process for obtaining moving average value of RSRP measurement value by mobile station>

[0050] Figure 5 is a diagram showing the RSRP measurement values ​​of the beam set in the mobile station 1 arranged by beam. The following explanation of the creation of report data will be based on the RSRP measurement values ​​of the beam set shown in Figure 5. Figure 5 is based on the system configuration shown in Figure 1. In Figure 5, the vertical axis indicates time, i.e., the number of measurements, and the horizontal axis indicates the beam number. The order of the measurement cycles is indicated by variable k (k > 0). The measurement cycle is set to Tm. The number of the measurement beam is indicated by variable n. Where N is the number of measurement beams, n takes values ​​from 1 to N. In the example shown in Figure 5, N = 6.

[0051] The data communication beam is designated b0_(θ_(0), m_(0)). The measurement beam is designated bn_(θ_(n), m_(n)). m_(n) indicates the transmission point. θ_(n) indicates the index corresponding to the azimuth angle. A beam may simply be referred to as bn. The characters in parentheses after the underscore are displayed as subscripts in the figures.

[0052] In the first embodiment, the moving average value of RSRP is acquired as report data for each of the data communication beam b0 and the measurement beam bn. Hereinafter, the moving average value of RSRP when the kth RSRP measurement is performed for the beam set will be described.

[0053] First, the control unit 11 obtains the moving average window size Lk as the largest integer equal to or less than the value calculated by the following equation 1. λ is the wavelength. v is the moving speed of the mobile station 1. Cλ is a coefficient. Tm is the measurement period. λ is calculated as the reciprocal of the frequency f used by the mobile station 1. Cλ is a value indicating a multiple of the wavelength, and for example, a value specified in the range from 2 to 10 is used. The moving speed v may be a measured value, or a predetermined value may be used.

[0054] The moving average window size Lk calculated by Equation 1 indicates the number of samples, i.e., the number of times RSRP is measured. The moving average window size Lk calculated by Equation 1 becomes smaller the faster the moving speed of the mobile station 1 and the higher the frequency used. In other words, the moving average window size Lk calculated by Equation 1 is calculated as a size that takes into account probabilistic fluctuations in the received signal strength measured by the mobile station, and can reduce the impact of probabilistic instantaneous fluctuations in the received signal strength in the moving average value. This can prevent frequent beam update requests. Note that if the control device 2 specifies a lifetime for the current beam set, the value obtained by dividing the lifetime by the measurement period Tm may be used as the upper limit of the moving average window size Lk.

[0055] Next, the control unit 11 obtains the forgetting factor η based on the following equation 2. The constant Cη is a value equal to or greater than 1. The forgetting factor η calculated by equation 2 decreases as the moving average window size Lk increases, and decreases as the moving average window size Lk decreases. The half-life is approximately Cη×Lk / 2.8854.

[0056] Based on the moving average window size Lk and the forgetting factor η, the control unit 11 calculates the moving average value γ(b0) of the communication beams included in the beam set and the moving average value γ(bn) of the RSRP of each measurement beam at the time the kth measurement is completed. The k-ith RSRP measurement value of the nth beam bn is defined as s_(n, k-i). The variable i takes values ​​in the order of Lk-1 to 0. The moving average value of the RSRP of the nth beam bn from the k-(Lk-1)th to the k-ith measurement is defined as S_(n, k-i). S_(n, k-i) is calculated using the following equation 3. w_(k-i) is the weight for the k-ith measurement value. The weight w_(k-i) is calculated using equation 4. The initial value of the weight w_(1) is 1. In this case, the initial value of the moving average value S_(n, 1) is s_(n, 1). The moving average value of the communication beam b0 can be calculated using the following equation 3, similar to that of the measurement beam bn, with n = 0. The moving average value γ(bn) of the RSRP of each beam included in the beam set is an example of "first information."

[0057] Since the forgetting factor η calculated by the above equation 2 is a value of 0<η<1, the range of values ​​of the weight w_(k-i) calculated based on the above equation 4 is 1<w_(k-i)<2. Equation 3 is an exponential moving average equation, and in the moving average value S_(n,k-i) calculated by equation 3, the newer the measurement value, the greater the weight assigned. Furthermore, in equation 3, the older the measurement value, the smaller the weight exponentially. Note that if the number of measurement values ​​stored in the measurement result storage unit 13 is less than Lk, the moving average value γ(bn) may be calculated by equation 3 using all data stored in the measurement result storage unit 13. That is, if the current number of measurements k is less than the moving average window size Lk, the variable i in equations 3 and 4 takes values ​​in the order of k-1 to 0, instead of Lk. 1 / w_(k-i) in equation 3 is an example of a "first coefficient."

[0058] The moving average value γ(bn) of the RSRP of each beam calculated from the above equations 1 to 4 becomes smaller as the speed of the mobile station 1 increases and as the frequency used by the mobile station 1 increases, and the weight of the newer measurement value increases. On the other hand, the moving average value γ(bn) of the RSRP of each beam calculated from the above equations 1 to 4 becomes larger as the speed of the mobile station 1 decreases and as the frequency used by the mobile station 1 decreases, and the difference in weight between the first to kth measurement values ​​decreases.

[0059] Since the window size of the moving average value of the RSRP of a beam set is Lk, the measurement result storage unit 13 may be configured to hold the measured values ​​of the RSRP of the beam set for Lk times. Alternatively, taking into account the forgetting factor η, the measurement result storage unit 13 may be configured to hold the measured values ​​of the RSRP of the beam set for L = log(0.01) / log(η) times.

[0060] According to the above formulas 1 and 2, the moving average window size Lk and the forgetting factor η are values ​​that depend on the moving speed v of the mobile station 1. For example, the lifetime of a beam set is set in seconds or shorter time units. On the other hand, the moving speed of the mobile station 1 does not change significantly in seconds or shorter time units, and the moving speed of the mobile station 1 can be considered constant over such short periods. Therefore, in the first embodiment, the same values ​​of the moving average window size Lk and the forgetting factor η are used while RSRP measurements are being performed for one beam set. For example, in the first embodiment, the values ​​of the moving average window size Lk and the forgetting factor η calculated using the measured value of the moving speed of the mobile station 1 when the beam set is notified from the control device 2 are used to calculate the moving average value of the measured value of RSRP for that beam set. However, the moving speed of the mobile station 1 used to calculate the moving average window size Lk and the forgetting factor η are not limited to this, and for example, a preset value may be used.

[0061] If the same values ​​are used for the moving average window size Lk and the forgetting factor η while RSRP measurements are being performed for one beam set, the difference between the moving average calculated from the measurement values ​​for the moving average window size Lk and the moving average calculated from the measurement values ​​for all measurements is negligibly small. This is because, in Equation 3, the older the measurement value, the smaller the weight exponentially. Furthermore, up to the moving average window size Lk, the moving average calculated from the measurement values ​​for the moving average window size Lk, as calculated using Equation 3, is the same as the moving average calculated from the measurement values ​​for all measurements. Therefore, in the first embodiment, by updating the moving average using Equation 3 each time a beam is measured, the mobile station 1 only needs to store the latest moving average and does not need to store the measurement values ​​for each measurement. This allows the mobile station 1 to limit the memory capacity of the main memory device 102 reserved as the measurement result memory unit 13 to the data size of the number of beams included in the beam set multiplied by the moving average value.

[0062] As described above, in the first embodiment, the mobile station 1 uses the same values ​​for the moving average window size Lk and the forgetting factor η while RSRP measurements are being performed for one beam set, updates the moving average value based on Equation 3 for each measurement, and reports the moving average value calculated from the measurement values ​​for all measurements to the control device 2. Hereinafter, in the first embodiment, the moving average value S_(n, i) of the measurement values ​​from the first to the i-th measurement for the nth beam is calculated using the following Equations 3A and 4A. In Equations 3A and 4A, the variable i takes values ​​from 2 to k. 1 / w_(i) in the following Equation 3A is an example of a "first coefficient".

[0063] <Processing Flow> Figure 6 is an example of a flowchart of a reporting process of RSRP measurement results of a beam set by the mobile station 1. The process shown in Figure 6 is repeatedly executed while the wireless communication device 106 of the mobile station 1 is in operation. The process shown in Figure 6 is executed mainly by the CPU 101 of the mobile station 1, but for convenience, the description will be made focusing on the functional components.

[0064] In OP11, the control unit 11 determines whether or not a beam set has been received from the control device 2. If a beam set has been received from the control device 2 (OP11: YES), the processing proceeds to OP12. If a beam set has not been received from the control device 2 (OP11: NO), the processing proceeds to OP15.

[0065] In OP12, the control unit 11 updates the beam set to be used to the received beam set, and refreshes the measurement result storage unit 13. In OP13, the control unit 11 acquires the moving speed of the mobile station 1, and acquires the moving average window size Lk using Equation 1. In OP14, the control unit 11 acquires the forgetting factor η using Equation 2.

[0066] In OP15, the control unit 11 determines whether or not the timing for measuring RSRP has arrived. If the timing for measuring RSRP has arrived (OP15: YES), the process proceeds to OP16. If the timing for measuring RSRP has not arrived (OP15: NO), the control unit 11 enters a standby state until the timing for measuring RSRP arrives. It is assumed that an opportunity for communication between the control device 2 and the control unit 2 to report the measurement results has been provided before the process of OP15.

[0067] In OP16, the control unit 11 acquires the measurement value of the RSRP of the beam set from the measurement unit 12. In OP17, the control unit 11 calculates the moving average value γ(bn) of each beam based on Equations 3A and 4A using the forgetting factor η acquired in OP14, and updates the moving average value γ(bn) of each beam held in the measurement result storage unit 13 with the newly calculated moving average value γ(bn). For example, the moving average value γ(bn) of each beam held in the measurement result storage unit 13 is overwritten and saved.

[0068] In OP18, the control unit 11 determines whether or not to report the measurement results of the RSRP of the beam set to the control device 2. If the reporting conditions are met, the control unit 11 decides to report the measurement results to the control device 2 (OP18: YES), and the processing proceeds to OP19. If the reporting conditions are not met, the control unit 11 decides not to report the measurement results to the control device 2 (OP18: NO), and the processing proceeds to OP11.

[0069] In OP19, the control unit 11 creates report data to be sent to the control device 2. Details of the report data creation process will be described later. In OP19, the control unit 11 transmits the report data to the control device 2. Thereafter, the process shown in Fig. 6 ends, and is repeatedly executed from OP11.

[0070] Fig. 7 is an example of a flowchart of the beam management process of the control device 2. The process shown in Fig. 7 is started, for example, when an initial beam set is determined by carrying out a beam selection procedure with the mobile station 1. The process in Fig. 7 is executed by the CPU of the control device 2, but for convenience, the description will be focused on the functional components.

[0071] In OP31, the control unit 21 determines whether or not a report of the measurement result of the RSRP of the beam set has been received from the mobile station 1. If report data has been received from the mobile station 1 (OP31: YES), the processing proceeds to OP32. If report data has not been received from the mobile station 1 (OP31: NO), the processing shown in Fig. 7 ends and is restarted.

[0072] In OP32, the control unit 21 determines whether the beam set has been updated. The determination of whether the beam set has been updated may be made based on the moving average value of the RSRP of the received beam set. For example, similar to the reporting conditions, one or more of the following conditions must be met: the moving average value of the RSRP of the data communication beam is less than a predetermined threshold, the moving average value of the RSRP of the measurement beam is equal to or greater than a predetermined threshold, and there is a measurement beam with a higher moving average value of the RSRP than the data communication beam. If the beam set has been updated (OP32: YES), the processing proceeds to OP33. If the beam set has not been updated (OP32: NO), the processing shown in FIG. 7 ends.

[0073] In OP33, the control unit 21 selects a beam set based on the measurement results of the RSRP of the beam set from the mobile station 1. The beam set selection method may be, for example, implementing a beam selection procedure specified in the 3GPP standard or any other existing method. In OP34, the control unit 21 transmits the newly selected beam set to the mobile station 1. Thereafter, the processing shown in Figure 7 ends. The processing shown in Figure 7 is an example of "beam management" of the "transmitting side device".

[0074] Figure 8 is a diagram showing an example of a sequence of beam management processing in communication system 100. In S101, the control device 2 selects a beam set. The selection of the beam set in S101 may be the selection of the initial beam set, or may be the selection of a beam set based on the measurement results of the RSRP of the beam set. In S102, the control device 2 transmits the newly selected beam set to the mobile station 1. The mobile station 1 receives the new beam set from the control device 2 (OP11: YES in Figure 6).

[0075] In S103, the mobile station 1 updates the beam set to be used to the received beam set and refreshes the measurement result storage unit 13 (OP12 in FIG. 6). In S104, the mobile station 1 calculates the moving average window size Lk and the forgetting factor η (OP13 and OP14 in FIG. 6). In S105, since the measurement timing has arrived (OP15: YES in FIG. 6), the mobile station 1 measures the RSRP of the beam set (OP16 in FIG. 6). In S106, the mobile station 1 calculates the moving average value of each beam included in the beam set and updates the moving average value of each beam stored in the measurement result storage unit 13 (OP17 in FIG. 6). In S107, the measurement value in this measurement does not satisfy the reporting condition, and the mobile station 1 decides not to report to the control device 2 (OP18: NO in FIG. 6).

[0076] Thereafter, the RSRP measurement for the beam set received in S102 is repeated without reporting to the control device 2, and in S111, the kth measurement timing arrives (OP15: YES in FIG. 6), so the mobile station 1 measures the RSRP of the beam set (OP16 in FIG. 6). In S112, the mobile station 1 calculates the moving average value of each beam included in the beam set and updates the moving average value of each beam stored in the measurement result storage unit 13 (OP17 in FIG. 6). In S113, the reporting condition is satisfied for the kth measurement value, and the mobile station 1 decides to report to the control device 2 (P18: YES in FIG. 6). In S114, the mobile station 1 transmits report data to the control device 2, including the latest moving average value of each beam stored in the measurement result storage unit 13, as the measurement result of the RSRP of the beam set (OP19 in FIG. 6). The control device 2 receives report data from the mobile station 1 (OP31 in FIG. 7: YES).

[0077] In S115, the control device 2 selects a beam set based on the measurement result of the RSRP of the beam set from the mobile station 1 (OP32 in FIG. 7). In S116, the control device 2 transmits the selected beam set to the mobile station 1 (OP33 in FIG. 7). The mobile station 1 receives the new beam set from the control device 2 (OP11 in FIG. 6: YES).

[0078] <Effects of the First Embodiment> In the first embodiment, the mobile station 1 transmits the moving average value of the measurement values ​​for the moving average window size Lk for each beam included in the beam set as a report of the RSRP measurement results of the beam set to the control device 2. For example, the data size of the RSRP measurement results transmitted from the mobile station 1 to the control device 2 in S114 of FIG. 8 can be reduced from a data size of (number of beams included in the beam set) x (number of measurements k) x (data size of the RSRP measurement values) to a data size of (number of beams included in the beam set) x (data size of the moving average value of RSRP). This makes it possible to reduce the overhead required for beam management.

[0079] Furthermore, in the first embodiment, the moving average window size Lk is determined based on the moving speed and operating frequency of the mobile station 1, so that the probabilistic fluctuations in received signal strength corresponding to the moving speed and operating frequency of the mobile station 1 can be fully taken into account in the moving average value of RSRP. Furthermore, a forgetting factor based on the moving average window size Lk is used, so that the faster the moving speed of the mobile station 1 or / and the higher the operating frequency, the greater the influence of new measurement values ​​and the smaller the influence of old measurement values. Conversely, the slower the moving speed of the mobile station 1 or / and the lower the operating frequency, the less the influence of new measurement values ​​and old measurement values ​​can be taken into account in the moving average value of RSRP. In other words, the fluctuations in the radio wave reception environment of the mobile station 1 can be reflected in the moving average value of RSRP. Therefore, according to the first embodiment, the beam set for the mobile station 1 can be selected taking into account the probabilistic fluctuations in received signal strength and the fluctuations in the radio wave reception environment of the mobile station 1. This allows a more suitable beam set to be selected, improving the accuracy of selecting a beam set, including a data communication beam.

[0080] The accuracy of beam set selection refers to, for example, the probability of selecting a beam that provides a larger RSRP in the mobile station 1. The method of creating report data in the first embodiment can take into account fluctuations in the radio wave reception environment of the mobile station 1, and is therefore effective when applied to, for example, a mobile station 1 whose travel route is not fixed, or a mobile station 1 that is in an environment where the radio wave reception environment fluctuates drastically, such as a busy downtown area with a large number of tall buildings.

[0081] <Variation 1 of the First Embodiment: Variation of the Moving Average Value Based on the RSRP Measurement Value> In the first embodiment, the mobile station 1 uses the same values ​​for the moving average window size Lk and the forgetting factor η while RSRP measurements are being performed for one beam set, updates the moving average value based on Equation 3 for each measurement, and reports the moving average value calculated from the measurement values ​​for all measurements to the control device 2. Instead, in Variation 1, the mobile station 1 calculates the moving average window size Lk using Equation 1 and the forgetting factor η using Equation 2 each time a report is performed, and finds the moving average value of each beam included in the beam set using Equations 3 and 4.

[0082] Fig. 9 is an example of a flowchart of a process of reporting RSRP measurement results of a beam set by a mobile station 1 in Modification 1 of the first embodiment. The process shown in Fig. 9 is repeatedly executed while the wireless communication device 106 of the mobile station 1 is in operation. The process shown in Fig. 9 is executed mainly by the CPU 101 of the mobile station 1, but for convenience, the process will be described mainly focusing on the functional components.

[0083] In OP21, the control unit 11 determines whether or not a beam set has been received from the control device 2. If a beam set has been received from the control device 2 (OP21: YES), the processing proceeds to OP22. If a beam set has not been received from the control device 2 (OP21: NO), the processing proceeds to OP23.

[0084] In OP22, the control unit 11 updates the beam set to be used to the received beam set, and refreshes the measurement result storage unit 13. In OP23, the control unit 11 determines whether or not the timing to measure RSRP has arrived. If the timing to measure RSRP has arrived (OP23: YES), the processing proceeds to OP15. If the timing to measure RSRP has not arrived (OP23: NO), the control unit 11 enters a standby state until the timing to measure RSRP arrives. It is assumed that an opportunity to communicate with the control device 2 to report the measurement results has been provided before the processing of OP23.

[0085] In OP24, the control unit 11 acquires the measurement value of the RSRP of the beam set from the measurement unit 12. In OP25, the control unit 11 stores the acquired measurement value of the RSRP of the beam set in the measurement result storage unit 13.

[0086] In OP26, the control unit 11 determines whether or not to report the measurement results of the RSRP of the beam set to the control device 2. If the reporting conditions are met, the control unit 11 decides to report the measurement results to the control device 2 (OP26: YES), and the processing proceeds to OP27. If the reporting conditions are not met, the control unit 11 decides not to report the measurement results to the control device 2 (OP26: NO), and the processing proceeds to OP21.

[0087] In OP27, the control unit 11 acquires, for example, a measurement value of the moving speed of the mobile station 1, and acquires the moving average window size Lk using Equation 1. In OP28, the control unit 11 acquires the forgetting factor η using Equation 2. In OP29, the control unit 11 acquires the moving average value of each beam included in the beam set using Equations 3 and 4.

[0088] In OP29A, the control unit 11 transmits report data including the moving average value of each beam included in the beam set acquired in OP29 to the control device 2. After that, the processing shown in Fig. 9 ends, and the processing shown in Fig. 9 is started repeatedly.

[0089] In OP29, if the measurement values ​​stored in the measurement result storage unit 13 do not fill the moving average window size Lk times, the moving average value γ(bn) may be calculated using all data stored in the measurement result storage unit 13 according to Equation 3. In FIG. 9, after determining whether or not to report the RSRP measurement results of the beam set to the control device 2 in OP26, the moving average value of RSRP is calculated for each beam included in the beam set, but this is not limited to this. For example, before determining whether or not to report in OP26, the moving average value of RSRP for each beam included in the beam set may be calculated, and whether or not to report may be determined using, as one of the reporting conditions, a condition such as the moving average value of the RSRP of the data communication beam being equal to or less than a threshold value.

[0090] In the first modification of the first embodiment, since the window size of the moving average value of the RSRP of the beam set is Lk, a storage capacity sufficient to hold the measurement values ​​of the RSRP of the beam set for Lk times is secured as the storage capacity of the measurement result storage unit 13. Alternatively, taking into account the forgetting coefficient η, a storage capacity sufficient to hold the measurement values ​​of the RSRP of the beam set for L = log(0.01) / log(η) times may be secured as the storage capacity of the measurement result storage unit 13.

[0091] In the first modification of the first embodiment, when it is decided to perform reporting, the moving average window size Lk and the forgetting factor η are calculated, and the moving average value of each beam included in the beam set is calculated. This makes it possible to report RSRP measurement results that take the radio wave reception environment into more accurate consideration to the control device 2.

[0092] <Modification 2 of First Embodiment: Modification of Moving Average Value Based on RSRP Measurement Value> In the first embodiment, the moving average value of RSRP is reported to the control device 2 as the measurement result of the RSRP of the beam set. The method for calculating the moving average value of RSRP reported to the control device 2 as the measurement result of the RSRP of the beam set is not limited to Equation 3, and for example, the moving average value obtained by either Equation 5 or Equation 6 below may be reported to the control device 2 as the measurement result of the RSRP of the beam set.

[0093] Equations 5 and 6 are equations for calculating a moving average value using the moving average window size calculated by equation 1. Equations 5 and 6 do not use the forgetting factor η calculated by equation 2 and are simple equations, so that the processing load on mobile station 1 involved in calculating the moving average value of RSRP can be reduced. Equation 5 is an equation for a simple moving average. Equation 6 is an equation for a weighted moving average, and is used to calculate a moving average value in which newer measurement values ​​have a greater influence.

[0094] <Modification 3 of First Embodiment: Modification of Reported Statistical Values ​​of RSRP Measurement Values>

[0095] In the first embodiment, the moving average value of RSRP is reported to the control device 2 as the measurement result of RSRP of the beam set. The measurement result of RSRP of the beam set that is reported to the control device 2 is not limited to the moving average value, but may be any statistical value of the measurement value of RSRP over a predetermined period. For example, if it is decided to report to the control device 2 on the kth measurement of the beam set, the statistical value calculated by the following equation 7 may be reported to the control device 2 as the measurement result of RSRP of the beam set. In equation 7, the variable i takes values ​​from 1 to k.

[0096]

[0097] In Equation 7, the value obtained by multiplying the measurement value s_(n, i) in the i-th measurement by the forgetting factor η is added to the value obtained by multiplying the statistical value S_(n, i-1) up to the i-1-th measurement by 1-η. Therefore, the mobile station 1 does not need to store the measurement value of each measurement, but simply stores the value of Equation 7, and each time a new measurement is performed, adds the value obtained by multiplying the measurement value by the power of the forgetting factor η. Therefore, when Equation 7 is used to determine the RSRP statistical value to be reported as the measurement result of the RSRP of the beam set, the size of the storage area of ​​the main storage device 102 reserved as the measurement result storage unit 13 can be kept small.

[0098] The forgetting factor η in Equation 7 is a value in the range of 0≦η≦1. For example, it may be the reciprocal of a value calculated by using a predetermined value as the velocity of the mobile station 1 in Equation 2, or it may be a predetermined constant. Equation 7 makes it possible to calculate a statistical value that has a greater influence as the measurement value becomes more recent.

[0099] <Variation 4 of First Embodiment> In Variation 4 of the first embodiment, the mobile station 1 switches the method of calculating the RSRP statistical value based on the speed and frequency. For example, when calculating the moving average value using the method shown in Variation 1 of the first embodiment, the slower the speed of the mobile station 1 and / or the smaller the frequency used, the larger the moving average window size Lk becomes, and the greater the number of samples becomes. Accordingly, the storage area and size of the measurement result storage unit 13 also become larger. Therefore, in Variation 3, the mobile station 1 calculates the moving average window size Lk using Equation 1, and if the moving average window size Lk is equal to or greater than a threshold, determines to report, for example, the statistical value calculated using Equation 7 to the control device 2 as the measurement result of the RSRP of the beam set.

[0100] Fig. 10 is an example of a flowchart of a process for reporting RSRP measurement results of a beam set by a mobile station 1 in Modification 4 of the first embodiment. The process shown in Fig. 10 is started when the wireless communication device 106 of the mobile station 1 is started, and is executed repeatedly. The process shown in Fig. 10 ends when the wireless communication device 106 of the mobile station 1 is stopped.

[0101] In OP41, the control unit 11 determines whether or not a beam set has been received from the control device 2, and if a beam set has been received (OP41: YES), the control unit 11 updates the beam set and refreshes the measurement result storage unit 13 (OP42). If a beam set has not been received (OP41: NO), the processing shown in Fig. 10 ends.

[0102] In OP43, the control unit 11 obtains the moving average window size Lk by Equation 1. The velocity of the mobile station 1 is determined using the measured value at this time point. In OP44, the control unit 11 determines whether or not the moving average window size Lk is less than the threshold value TH. If the moving average window size Lk is less than the threshold value TH (OP44: YES), the processing proceeds to OP45.

[0103] 9 is performed, the moving average value of RSRP is calculated by Equation 3, and is reported to the control device 2 as the measurement result of RSRP of the beam set. When the moving average value of RSRP calculated by Equation 3 is reported to the control device 2 as the measurement result of RSRP of the beam set (OP29A), the processing proceeds to OP46. In OP46, the control unit 11 determines whether or not a beam set has been received from the control device 2, and if a beam set has been received (OP46: YES), the processing proceeds to OP42. If a beam set has not been received (OP46: NO), the processing proceeds to OP45.

[0104] In OP44, if the moving average window size Lk is equal to or larger than the threshold value TH (OP44: NO), the process proceeds to OP51. The processes from OP51 to OP56 are processes for reporting the statistical value calculated by Equation 7 as the measurement result of the RSRP of the beam set to the control device 2.

[0105] In OP51, the control unit 11 determines whether or not the timing for measuring RSRP has arrived, and if the timing for measuring RSRP has arrived (OP51: YES), the control unit 11 acquires the measured value of RSRP of the beam set from the measurement unit 12 (OP52). If the timing for measuring RSRP has not arrived (OP51: NO), the control unit 11 enters a standby state until the timing for measuring RSRP arrives.

[0106] In OP53, the control unit 11 obtains the statistical value of RSRP in the current measurement for each beam included in the beam set using Equation 7, and stores the obtained value in the measurement result storage unit 13. In the measurement result storage unit 13, the statistical value of RSRP in the previous measurement is overwritten and saved with the statistical value of RSRP in the current measurement. Since the statistical value of RSRP in the previous measurement is held in the measurement result storage unit 13, the statistical value of RSRP in OP53 using Equation 7 is obtained by adding the value obtained by multiplying the statistical value of RSRP up to the previous measurement by 1-η to the value obtained by multiplying the current measurement value by η.

[0107] In OP54, the control unit 11 determines whether or not to report the measurement results of the RSRP of the beam set to the control device 2. If the reporting conditions are met, the control unit 11 decides to report the measurement results to the control device 2 (OP54: YES), and reports the RSRP statistical values ​​in the current measurement for each beam acquired in OP53 to the control device 2 as the measurement results of the RSRP of the beam set (OP55). If the reporting conditions are not met, the control unit 11 decides not to report the measurement results to the control device 2 (OP54: NO), and the processing proceeds to OP51.

[0108] In OP56, the control unit 11 determines whether or not a beam set has been received from the control device 2, and if a beam set has been received (OP56: YES), the processing proceeds to OP42. If a beam set has not been received (OP56: NO), the processing proceeds to OP51.

[0109] According to the fourth modification of the first embodiment, when the moving average window size Lk based on the moving speed and operating frequency of the mobile station 1 is greater than a threshold, the statistical value calculated by Equation 7 is reported to the control device 2 as the measurement result of the RSRP of the beam set. This prevents the size of the measurement result storage unit 13 from increasing. Furthermore, when the moving average window size Lk is greater than the threshold, the moving speed of the mobile station 1 is likely to be slow and there is little change in the radio wave reception environment. Therefore, for each beam of the beam set, the RSRP statistical value calculated by Equation 7 and the moving average value calculated by Equation 3 are likely to reflect the measurement value at each time to the same degree, and the influence of differences in the statistical values ​​used in beam selection can be minimized. Note that when the moving average window size Lk based on the moving speed and operating frequency of the mobile station 1 is greater than a threshold, the moving average values ​​obtained by Equations 3 and 4 of the first embodiment may be calculated instead of the statistical value calculated by Equation 7.

[0110] <Second embodiment> In the second embodiment, the mobile station 1 reports the measurement result of the RSRP of the beam set, which is coded and compressed, to the control device 2. In the second embodiment, explanations common to the first embodiment will be omitted. In the second embodiment, the system configuration of the communication system 100, and the hardware configuration and functional configuration of the mobile station 1 and the control device 2 are the same as those in the first embodiment.

[0111] 11 is a diagram illustrating an example of quantization of the RSRP measurement value of a beam set. In the second embodiment, the mobile station 1 quantizes the RSRP measurement value using multiple thresholds in preparation for encoding the RSRP measurement value of a beam set.

[0112] The upper part of Figure 11 shows an example of changes in the measured RSRP value of one beam. For example, in the example shown in Figure 11, each measured value is classified into one of classes from 0 to 3 and quantized using three thresholds. The three thresholds may be, for example, MCS (Modulation and Coding Scheme) receiving sensitivity +20 dB, MCS receiving sensitivity +3 dB, and MCS receiving sensitivity. However, the threshold values ​​used for quantizing the measured RSRP value are not limited to these. Receiving sensitivity is the minimum signal strength guaranteed for demodulating the MCS.

[0113] The bottom of Figure 11 shows an example of the result of quantizing the measured RSRP value of a beam set to any of 0 to 3 using the above three thresholds. The example shown in Figure 11 is the result of quantizing the measured RSRP value of the beam set shown in Figure 5. Note that the thresholds used to quantize the measured RSRP value of a beam set are not limited to three, and may be more or less than three.

[0114] By quantizing the RSRP measurement values ​​of a beam set, the data size of a single measurement value of one beam can be reduced. Furthermore, the RSRP measurement values ​​of the beam set after quantization retain the relative relationships between the RSRP measurement values, such as the strength and weakness, and the tendency of fluctuation. Therefore, in the control device 2, the selection of a beam set based on the RSRP measurement values ​​of the beam set after quantization can be performed almost in the same way as when using the RSRP measurement values ​​of the beam set before quantization.

[0115] 12 is a diagram showing an example of encoding of the RSRP measurement values ​​of a quantized beam set. In the second embodiment, the mobile station 1 encodes the RSRP measurement values ​​of a quantized beam set using run-length encoding. FIG. 12 shows encoded data when the RSRP measurement values ​​of a quantized beam set are encoded using sweep pattern A. In sweep pattern A, as shown in FIG. 12, the quantized measurement values ​​are swept in ascending order of beam number, starting from beam b0, from the oldest measurement value for one beam to the oldest measurement value for the other beam, and then the quantized measurement values ​​are swept in order to move on to the next beam.

[0116] When the example of the RSRP measurement value of the quantized beam set shown in FIG. 11 is run-length encoded using sweep pattern A, the resulting encoded data is (3,7), (2,8), (3,1), (2,1), (1,6), (0,8), (1,1), (0,6), (1,1), (2,1), (0,3), (1,9), and (0,4). (p,h) indicates that the value of p occurs h times in succession. If the size of the RSRP measurement value is 2 bits, sending the RSRP measurement value of the beam set shown in FIG. 11 as is will result in 2 bits x 56 measurement values ​​= 112 bits. On the other hand, when encoding using sweep pattern A, the length will be (2 bits (intensity) + 4 bits (run length)) x 13 = 78 bits, which reduces the size of the data reported to the control device 2.

[0117] 13 is a diagram showing an example of encoding the RSRP measurement values ​​of a quantized beam set. Fig. 13 shows encoded data when the RSRP measurement values ​​of a quantized beam set are encoded using sweep pattern B. In sweep pattern B, for example, as shown in Fig. 13, the quantized measurement values ​​are swept in ascending order of beam number starting from beam b0, with the oldest measurement value for beam b0 being swept first, before moving on to the next beam, and the beams other than beam b0 are swept in the opposite direction to the previous beam.

[0118] When the example of the measured RSRP values ​​of the quantized beam set shown in Figure 11 is run-length encoded using sweep pattern B, the resulting encoded data is (3,7), (2,1), (3,1), (2,8), (1,6), (0,1), (1,1), (0,13), (1,1), (2,1), (1,5), (0,3), (1,4), (0,4). When encoded using sweep pattern B, the data becomes (2 bits (intensity) + 4 bits (run length)) x 14 = 84 bits, which reduces the size of the data reported to the control device 2.

[0119] Run-length encoding using sweep pattern A has the characteristic of being able to obtain a higher compression rate when there is a high correlation between RSRP measurement values ​​in the time direction. Run-length encoding using sweep pattern B has the characteristic of being able to obtain a higher compression rate when there is a high correlation between RSRP measurement values ​​in the time direction and the space direction. Whether sweep pattern A or B is to be used may be set by an administrator of communication system 100. Alternatively, mobile station 1 may perform encoding using both patterns and report the encoded data using the pattern with the smaller data size to control device 2. In this case, mobile station 1 transmits information indicating the sweep pattern along with the encoded data to control device 2. In the second embodiment, the encoded data is an example of "first information."

[0120] In the second embodiment, the arrangement of beams in encoding is assumed to be commonly recognized between the mobile station 1 and the control device 2. For example, a rule for arranging beams in encoding, such as ascending order of beam numbers, may be set in advance between the mobile station 1 and the control device 2, the control device 2 may determine the arrangement of beams in encoding and notify the mobile station 1 together with the beam set, or the mobile station 1 may determine the arrangement of beams in encoding and notify the control device 2 together with the report data. The arrangement of beams in encoding is not limited to ascending order of beam numbers, but may be descending order of beam numbers or random. The arrangement of beams in encoding may be changed for each sweep pattern or may be changed for each report.

[0121] When reporting coded data of the RSRP measurement values ​​of the beam set to the control device 2, the more data there is, the more accurately the beam set can be selected. Therefore, in the second embodiment, the measurement result storage unit 13 stores the RSRP measurement values ​​of the beam set up to the upper limit of the allocated memory.

[0122] Fig. 14 is an example of a flowchart of a report data creation process of a mobile station 1 in the second embodiment. In the second embodiment, the mobile station 1 executes the reporting process of the RSRP measurement results of the beam set in the same flow as the process shown in Fig. 9 in Modification 1 of the first embodiment, for example. However, for the report data creation process, the process shown in Fig. 14 is executed instead of OP27 to OP29 in Fig. 9. That is, in the second embodiment, after the kth measurement, when the reporting condition is satisfied and it is determined to report the RSRP measurement results of the beam set to the control device 2 (OP26: YES in Fig. 9), the process shown in Fig. 14 is executed.

[0123] In OP61, the control unit 11 reads out and quantizes all RSRP measurement values ​​of the data set up to the kth time stored in the measurement result storage unit 13. In OP62, the control unit 11 encodes all quantized RSRP measurement values ​​using run-length encoding. The sweep pattern may be a pattern designated in advance, or the smaller size of the encoded data of both patterns may be used as report data. Thereafter, the process proceeds to OP29A in FIG. 9 , and the encoded data is transmitted to the control device 2 as the measurement result of the RSRP of the beam set.

[0124] Fig. 15 is an example of a flowchart of the beam set selection process of the control device 2 in the second embodiment. The process shown in Fig. 15 corresponds to the process in OP33 of Fig. 7 in the second embodiment. That is, the process shown in Fig. 15 is executed when a report of the measurement results of the RSRP of the beam set is received from the mobile station 1.

[0125] In OP71, the control unit 21 decodes the coded data included in the report data received from the mobile station 1 and obtains the measured value of the RSRP of the beam set after quantization. In OP72, the control unit 21 obtains a new beam set using pattern matching or a machine learning model. Hereinafter, the measured value of the RSRP of the beam set after quantization of the coded data included in the report data received from the mobile station 1 will be simply referred to as the report data.

[0126] Here, the combination of the beam pattern of the beam transmitted from each transmission point m_(n) and the beam pattern of the data communication beam is called a beam set model. A beam pattern is simply the direction and width of a beam.

[0127] When acquiring a new beam set by pattern matching, the control unit 21 regards, for example, report data such as that shown in Fig. 11 as image data and performs pattern matching on the vast amount of report data acquired in the past and the quantized RSRP. The control unit 21 extracts past report data whose degree of match with the report data is equal to or greater than a threshold, and selects a new beam set taking into consideration the beam update results in this report data (such as the duration of high communication quality).

[0128] When a new beam pattern is obtained using a machine learning model, a machine learning model that has learned the relationship between the quantized RSRP and the beam set model for multiple beam set models prepared in advance is used. The control unit 21, for example, inputs the measured value of the quantized RSRP of the report data into the machine learning model and obtains the probability of classification for each of the multiple beam pattern models as an output. The control unit 21, for example, determines the beam set model with the highest classification probability as the new beam set model to be notified to the mobile station 1.

[0129] When a new beam set to be notified to the mobile station 1 is selected, the process proceeds to OP34 in FIG.

[0130] <Effects of the Second Embodiment> In the second embodiment, the measurement values ​​of the RSRP of the beam set are quantized and encoded, thereby reducing the size of the data reported to the control device 2. The data obtained by quantizing and encoding the measurement values ​​of the RSRP of the beam set includes data corresponding to the measurement values ​​of each beam included in the beam set at all measurement times, and therefore the control device 2 can be notified of the probabilistic fluctuations in the received signal strength and the trends in the temporal and spatial fluctuations of the beams.

[0131] Furthermore, the accuracy of beam selection can be improved by accumulating beam sets that provide good past RSRP values ​​as beam set models used in beam selection in the control device 2. Therefore, the method of quantizing and encoding the RSRP measurement values ​​of the beam set and reporting the resulting encoded data to the control device 2 can be applied to, for example, a mobile station 1 that moves in a space with few obstructions and little fluctuation in the radio wave reception environment, such as a drone, and a mobile station 1 that repeatedly moves on a predetermined route, such as a train, thereby achieving a greater effect of enabling more accurate beam set selection. Note that the encoding method is not limited to the run-length method, and a discrete cosine transform method such as JPEG may also be used.

[0132] <Variation of Second Embodiment> In a variation of the second embodiment, the mobile station 1 reduces the size of encoded data reported to the control device 2 by narrowing down the measurement values ​​to be transmitted to the control device 2 from among the measurement values ​​of RSRP to be encoded.

[0133] Fig. 16 is a diagram showing an example of a method for selecting a beam to be reported. As one method for selecting a beam to be reported, the mobile station 1 selects, as the transmission target, the beams for measurement that have a predetermined number of the top most recent measurement values. In the example shown in Fig. 16, of the six measurement beams, the RSRP measurement values ​​of beams b1 and b4, which have the top two measurement values, are transmitted to the control device 2, but beams b2, b3, b5, and b6 are not transmitted to the control device 2. That is, in the example shown in Fig. 16, coded data in which the RSRP measurement values ​​of beams b0, b1, and b4 are coded is transmitted to the control device 2.

[0134] 17 is a diagram showing an example of a method for selecting beams to be reported. As another method for selecting beams to be reported, the mobile station 1 selects measurement beams having a predetermined number of the top average measurement values ​​as transmission targets. In the example shown in FIG. 17, of the six measurement beams, the RSRP measurement values ​​of beams b1 and b2 having the top two average measurement values ​​are transmitted to the control device 2, but beams b3, b4, b5, and b6 are not transmitted to the control device 2. That is, in the example shown in FIG. 17, coded data obtained by coding the RSRP measurement values ​​of beams b0, b1, and b2 is transmitted to the control device 2.

[0135] 16 and 17 show measurement values ​​after quantization, but beams to be reported may be selected based on measurement values ​​before quantization. Furthermore, the method of selecting beams to be reported is not limited to the method shown in FIGS. 16 and 17. For example, other statistical values ​​such as the median of measurement values ​​may be used. Furthermore, for example, beams whose predetermined evaluation value (such as the latest measurement value or average value) is equal to or greater than a predetermined threshold may be selected as beams to be reported.

[0136] In addition, if an upper limit size is set for the report data to the control device 2, the mobile station 1 may select a beam to report by excluding beams with lower evaluation values ​​until the size of the report data becomes less than the upper limit size.

[0137] In addition to the encoded data, the mobile station 1 also reports the beam numbers included in the encoded data to the control device 2. After decoding the encoded data, the control device 2 complements the measurement values ​​of the beams that were not selected with a predetermined value that does not affect the beam selection, such as 0, and performs beam selection as described in Fig. 15 .

[0138] In the modified example of the second embodiment, by narrowing down the beams to be reported, it is possible to reduce the size of the data to be reported to the control device 2. Furthermore, since beams with good evaluation values ​​of the measurement values ​​are selected as the beams to be reported, it is possible to minimize the impact on the accuracy of beam selection caused by measurement values ​​of some beams not being reported.

[0139] Other Embodiments The above-described embodiment is merely an example, and the present disclosure can be implemented with appropriate modifications within the scope of the gist thereof.

[0140] In the first and second embodiments, the communication system 100 has been described assuming that it is a distributed MIMO system. However, the present invention is not limited to distributed MIMO, and the techniques described in the first and second embodiments can also be applied to normal MIMO.

[0141] In the first and second embodiments, the description has been given assuming that the communication system 100 includes a distributed base station and a mobile station 1. However, this is not limiting, and instead of the mobile station 1, a communication device that is fixed at a predetermined location may be included in the communication system 100. In the case of a fixed communication device, since it does not move, the speed is 0, and in the first embodiment, the moving average window size Lk diverges to infinity. Therefore, the moving average window size Lk may be calculated using a predetermined value as the speed.

[0142] The first and second embodiments have been described taking as an example a periodic report of the measurement results of the RSRP of a beam set from the mobile station 1. This is not limited to this, and even in an irregular report of the measurement results of the RSRP of a beam set from the mobile station 1, a moving average value or coded data may be reported as the measurement result of the RSRP of the beam set, as described in the first and second embodiments.

[0143] In the first and second embodiments, beam management in the control device 2 on the network side has been described. However, this is not limiting, and beam management in the mobile station 1 can also be applied by interchanging the processing of the mobile station 1 and the control device 2 in the first and second embodiments. That is, when the control device 2 receives a beam pattern from the mobile station 1, it may notify each distributed base station of the beam pattern of the mobile station 1, collect measurement values ​​of RSRP of the beam according to the beam pattern from the mobile station 1 from each distributed base station, and, similar to the mobile station 1 in the first and second embodiments, create report data from the measurement values ​​of RSRP for the beam pattern from the mobile station 1 and transmit the report data to the mobile station 1. In this case, the mobile station 1 may select a new beam pattern for the mobile station 1 based on the report data from the control device 2 and notify the control device 2. When the control device 2 notifies each distributed base station of the new beam pattern for the mobile station 1, each distributed base station performs regular measurement of RSRP for the beam pattern. In this case, however, the moving speed used to calculate the moving average window size Lk in the first embodiment is the moving speed of the transmitting mobile station 1. In beam management in the mobile station, the control device is an example of a "receiving device," and the mobile station 1 is an example of a "transmitting device."

[0144] In the first and second embodiments, the case where the measurement value of RSRP included in the beam set is reported has been described, but the measurement value to which the techniques described in the first and second embodiments can be applied is not limited to this. For example, the techniques described in the first and second embodiments can be applied to reports of measurement values ​​that are affected by probabilistic fluctuations in received signal strength such as RSSI (Received Signal Strength Indicator), RSRQ (Reference Signal Received Quality), and SINR, or trends in temporal and spatial fluctuations of beams.

[0145] In the first and second embodiments, the description is based on the premise that the beam set includes one beam for data communication. In the first and second embodiments, even if the beam set includes multiple beams for data communication, the mobile station 1 can perform processing in the same manner as when the beam set includes one beam for data communication.

[0146] Furthermore, the processes and means described in this disclosure can be freely combined and implemented as long as no technical contradictions arise.

[0147] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. Alternatively, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration (server configuration) by which each function is realized can be flexibly changed.

[0148] The present disclosure can also be realized by supplying a computer program that implements the functions described in the above embodiments to a computer, and having one or more processors in the computer read and execute the program. Such a computer program may be provided to the computer on a non-transitory computer-readable storage medium connectable to the computer's system bus or via a network. Non-transitory computer-readable storage media include any type of medium suitable for storing electronic instructions, such as any type of disk, including magnetic disks (e.g., floppy disks, hard disk drives (HDDs), etc.), optical disks (e.g., CD-ROMs, DVDs, Blu-ray disks), read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic cards, flash memory, or optical cards.

[0149] DESCRIPTION OF SYMBOLS 1. Mobile station 2. Control device 11. Control unit 12. Measurement unit 13. Measurement result storage unit 21. Control unit 100. Communication system 101. CPU 102. Main storage device 103. External storage device 106. Wireless communication device 107. Antenna

Claims

1. A method in which a receiving device repeatedly measures one or more beams transmitted from one or more transmission points, obtains first information from a predetermined number of measurements for each of the one or more beams, the first information reflecting fluctuations in received signal strength during the predetermined number of measurement periods, and has a smaller data size than the predetermined number of measurements for each of the one or more beams, and transmits the first information to a transmitting device, wherein the transmitting device uses the first information for beam management.

2. The method according to claim 1, wherein the receiving device acquires, as the first information, a moving average value of the predetermined number of measurement values ​​obtained for each of the one or more beams.

3. The method according to claim 2, wherein the receiving device obtains the moving average value by multiplying the latest measurement value by a first coefficient and adding the result obtained by multiplying the moving average value of the measurement values ​​from the first measurement to the previous measurement by 1 minus the first coefficient, and the first coefficient is a value greater than 0 and less than 1.

4. The method according to claim 3, wherein the first coefficient is based on the moving speed and the frequency used by the receiving device.

5. The method according to claim 4, wherein the receiving device: acquires the first coefficient 1 / w_(i) using equations A to C, where 1 / w_(i) is the first coefficient in the i-th measurement, coefficients Cλ and Cη, a wavelength λ corresponding to the frequency used by the receiving device, v the moving speed of the receiving device, and a measurement period Tm; acquires the moving average S_(n,i) of the measurement values ​​up to the i-th measurement of the n-th beam included in the one or more beams, where S_(n,i) is the moving average of the measurement values ​​from the first to the i-th measurement of an n-th beam included in the one or more beams, and s_(n,i) is the i-th measurement of the n-th beam; and acquires the moving average S_(n,i) of the measurement values ​​up to the i-th measurement of the n-th beam using equation D, wherein variable n is an integer from 1 to the number of the one or more beams, variable i and the coefficients Cλ and Cη are each integers greater than or equal to 1, w_(1) is 1, and S_(n,1) is s_(n,1).

6. The method according to claim 2, wherein the predetermined number of times is a number of measurements corresponding to a moving average window, and the moving average window is based on the moving speed and the frequency used by the receiving device.

7. The method according to claim 6, wherein the receiving device obtains the moving average value by multiplying the most recent measurement value by a first coefficient for a number of measurements corresponding to the most recent moving average window, and adding the result obtained by multiplying the moving average value of the measurement values ​​from the start of the moving average window to the previous time by 1 minus the first coefficient, and the first coefficient is a value greater than 0 and less than 1.

8. The method of claim 2, further comprising the step of determining, based on the moving speed and frequency of the receiving device, whether the receiving device will use a first method of obtaining the moving average by taking a moving average of measurement values ​​for a number of measurements corresponding to a moving average window, or a second method of obtaining the moving average by multiplying the most recent measurement value by a first coefficient and adding, for each measurement, a value obtained by multiplying the moving average of the measurement values ​​from the first measurement to the previous measurement by 1 minus the first coefficient.

9. The method according to claim 1, wherein the receiving device converts the predetermined number of measurement values ​​for each of the one or more beams into one of a predetermined number of classes, and encodes the converted predetermined number of measurement values ​​for each of the one or more beams using a predetermined encoding method to obtain the first information.

10. The method according to claim 9, wherein the receiving device is configured such that the predetermined encoding method is run-length encoding.

11. The method according to claim 10, wherein the receiving device acquires the first information by reading the converted measurement values ​​in chronological order in a predetermined order for each of the one or more beams.

12. The method of claim 10, wherein the receiving device acquires the first information in a predetermined order for each of the one or more beams, starting with reading the converted measurement values ​​for the first beam in chronological order and reading the measurement values ​​for the nth beam in the reverse order of that for the (n-1)th beam, where n is a variable indicating a beam and is an integer between 1 and the number of the one or more beams.

13. The method of claim 10, wherein the receiving device: encodes the predetermined number of measurement values ​​for each of the one or more beams using the predetermined encoding method in a reading order that results in a smaller data size after encoding: a first reading order in which the converted measurement values ​​are read in chronological order for each of the one or more beams in a predetermined order; or a second reading order in which the converted measurement values ​​for the first beam are read in chronological order for each of the one or more beams in the predetermined order for each of the one or more beams, starting with the first beam in chronological order and reading the converted measurement values ​​for the nth beam in the reverse order to that for the (n-1)th beam; to obtain the first information; and transmits the first information and information based on the first reading order or the second reading order, whichever is adopted, to the transmitting device.

14. The method according to claim 9, wherein the receiving device obtains the first information by encoding the predetermined number of measurement values ​​for each of a predetermined number of beams whose most recent measurement value is the highest among the predetermined number of measurement values ​​using a predetermined encoding method.

15. The method according to claim 9, wherein the receiving device obtains the first information by encoding the predetermined number of measurement values ​​for each of a predetermined number of beams having the highest statistical values ​​of the predetermined number of measurement values ​​using the predetermined encoding method.

16. The method of claim 9, wherein the transmitting device decodes the first information into the predetermined number of converted measurement values ​​for each of the one or more beams, and performs beam management based on the predetermined number of converted measurement values ​​for each of the one or more beams.

17. A system including a receiving device and a transmitting device, wherein the receiving device performs the following: repeatedly measures one or more beams transmitted from one or more transmission points; acquires, from a predetermined number of measurement values ​​for each of the one or more beams, first information that reflects fluctuations in received signal strength during the predetermined number of measurement periods and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams; and transmits the first information to the transmitting device; and the transmitting device performs beam management based on the first information.

18. The system according to claim 17, wherein the receiving device acquires, as the first information, a moving average value of the predetermined number of measurement values ​​obtained for each of the one or more beams.

19. The system described in claim 17, wherein the receiving device converts the predetermined number of measurement values ​​for each of the one or more beams into one of a predetermined number of classes, and encodes the converted predetermined number of measurement values ​​for each of the one or more beams using a predetermined encoding method to obtain the first information.

20. A program for causing a computer to perform the following: repeatedly measuring one or more beams transmitted from one or more transmission points; obtaining first information, which reflects fluctuations in received signal strength during a predetermined number of measurement periods from a predetermined number of measurement values ​​for each of the one or more beams and has a smaller data size than the predetermined number of measurement values ​​for each of the one or more beams; and transmitting the first information to a transmitting device, wherein the first information is used by the transmitting device for beam management.

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