Control device, control method, and program

Abstract

To properly select a beam.SOLUTION: A control unit (1400) comprises an acquisition part (1410) which acquires a measurement result including information related to reception quality of a plurality of beams, an update part (1420) which updates, based upon the measurement result, a database including information representing relationship between a plurality of beams for a plurality of propagation environments, respectively, and a selection part (1430) which uses the database to execute selection processing to select a beam.SELECTED DRAWING: Figure 14

Description

[Technical Field]

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

[0002] Fifth generation (5G) mobile communication systems support high frequency bands such as millimeter wave bands. Because high frequency bands have large propagation losses, beamforming technology may be used to compensate for the propagation losses. Beamforming is a technique for changing the shape and direction (angle) of a beam by controlling the phase and amplitude of radio signals transmitted or received by multiple antenna elements.

[0003] Hereinafter, a combination of radio waves (signals) transmitted or received by multiple antenna elements is referred to as a "beam." Specifically, a beam obtained by combining signals transmitted by multiple antenna elements is referred to as a "transmit beam." A beam obtained by combining signals received by multiple antenna elements is referred to as a "receive beam."

[0004] Since the area covered by a single beam is limited, mobile communication systems may use multiple beams to secure a coverage area in a high frequency band. Patent Document 1 and Patent Document 2 disclose a base station that uses multiple beams. Patent Document 3 discloses a base station that selects a transmission beam for transmission to a terminal device from multiple beam candidates. Non-Patent Document 1 discloses a technology for selecting a user (terminal device) to communicate with. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2020-523872 [Patent Document 2] WO2019 / 155578 issue [Patent Document 3] WO2018 / 128048 issue [Non-patent literature]

[0006] [Non-Patent Document 1] Uchida et al., "Invited Lecture: Study on High-Frequency Band Distributed Antenna Systems for the 6G Era," IEICE Technical Report RCS2020-148, December 2020 Summary of the Invention [Problem to be solved by the invention]

[0007] In some situations, a wireless communication device (e.g., a base station) selects a beam to be used for communication with a terminal device based on a measurement result of reception quality reported from the terminal device. To this end, the wireless communication device selects a beam for measuring reception quality from among multiple beam candidates. If the reception quality falls below a predetermined level, a beam failure occurs. Therefore, the wireless communication device needs to select an appropriate beam so that the reception quality is at or above the predetermined level.

[0008] In 5G, a wireless communication device may have multiple transmission and reception points (TRPs). In this configuration, it is assumed that a first TRP and a second TRP are adjacent to each other and that the coverage areas of the first TRP and the second TRP overlap each other. In this case, when the first TRP and the second TRP communicate with a terminal device located in an area where their coverage areas overlap, interference occurs between the first TRP and the second TRP. Therefore, the wireless communication device needs to select an appropriate beam taking interference into consideration.

[0009] Although not limited to the above-mentioned situations, wireless communication devices are required to appropriately select beams in various situations. The present disclosure provides a technique for appropriately selecting beams. [Means for solving the problem]

[0010] In one or more embodiments, a control device is provided, comprising: an acquisition unit that acquires measurement results including information on reception qualities of a plurality of beams, an update unit that updates a database that includes information indicating relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results, and a selection unit that executes a selection process to select a beam using the database.

[0011] In one or more embodiments, a control method is provided, which includes obtaining measurement results including information regarding reception qualities of a plurality of beams, updating a database including information representing relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results, and performing a selection process to select a beam using the database.

[0012] In one or more embodiments, a program is provided that causes a computer including a processor and a memory to acquire measurement results including information on reception qualities of a plurality of beams, update a database including information indicating relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results, and perform a selection process that selects a beam using the database. [Effects of the Invention]

[0013] According to the above configuration, it is possible to appropriately select a beam. Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating an example of a wireless communication system according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a wireless terminal. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a control device. [Figure 4]FIG. 1 illustrates an example of the configuration of a wireless device. [Figure 5] FIG. 2 is a diagram illustrating an example of the configuration of a baseband signal processing unit. [Figure 6] 3A and 3B are diagrams illustrating an example of the configuration of a beam management unit and an example of the configuration of a storage unit. [Figure 7] FIG. 2 is a diagram conceptually illustrating an example of the data structure of a plurality of tables included in a first database. [Figure 8] 10 is a flowchart showing an example of the flow of a process for updating the first database. [Figure 9] 10 is a flowchart showing an example of the flow of a first selection process. [Figure 10] 10 is a flowchart showing an example of the flow of a second selection process. [Figure 11] FIG. 2 is a diagram conceptually illustrating an example of the data structure of a plurality of tables included in a second database. [Figure 12] FIG. 10 is a diagram conceptually illustrating an example of the data structure of a plurality of tables included in a third database. [Figure 13] FIG. 10 is a diagram conceptually illustrating an example of the data structure of a plurality of tables included in a fourth database. [Figure 14] FIG. 10 is a diagram illustrating an example of the configuration of a control device according to a second embodiment. [Figure 15] 10 is a flowchart showing an example of a processing flow of a control device according to the second embodiment. [Figure 16] FIG. 10 is a diagram illustrating an example of a combination of software and hardware that realizes the functions of a control device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] One or more embodiments will be described below with reference to the accompanying drawings. In this specification and drawings, elements that can be similarly described will be designated by the same reference numerals, and redundant description will be omitted.

[0016] The explanation will be given in the following order: 1. Overview of the embodiment 2. First embodiment 2-1. Wireless communication system configuration 2-2. Wireless terminal configuration 2-3.Configuration of wireless communication device 2-4.Control device configuration 2-5. Wireless device configuration 2-6. Configuration of the baseband signal processing section 2-7. Beam control unit configuration 2-8. Configuration of the first database 2-9. Example of operation of beam selection unit 2-10.Processing flow 2-11.Effects 2-12. Variations 3. Second embodiment 3-1.Control device configuration 3-2. Processing flow 4. Other Embodiments

[0017] <<1. Overview of the embodiment>> A summary of one or more embodiments is provided below.

[0018] (1)Technical issues As described above, a wireless communication device (e.g., a base station) is required to appropriately select a beam in various situations, such as when the wireless communication device selects a beam for measuring reception quality, when the wireless communication device selects a beam to be used for communication with a terminal device, and so on.

[0019] (2) Technical Features In order to solve the above problem, in one or more embodiments, a control device is provided, which includes an acquisition unit, an update unit, and a selection unit.

[0020] The acquisition unit acquires measurement results including information on the reception quality of multiple beams. The update unit updates the database based on the measurement results. The database includes information indicating the relationship between multiple beams for each of multiple propagation environments. The selection unit executes a selection process that selects a beam using the database.

[0021] The selection unit may select a relationship corresponding to the current propagation environment from the information representing the relationship, and perform the selection process using the selected relationship.

[0022] The information representing the relationship may include first information representing a first relationship between differences in reception quality among the plurality of beams.Furthermore, the information representing the relationship may include second information representing a second relationship between the number of reports of reception quality among the plurality of beams.

[0023] The above selection process may include at least one of a first selection process for selecting a beam to be used for measuring reception quality and a second selection process for selecting a beam to be used for communication with a wireless terminal.

[0024] According to the above configuration, the control device can appropriately select a beam. Note that the technical features of one or more embodiments described hereinafter are not limited to the above-mentioned technical features. Furthermore, one or more embodiments may provide other effects instead of or in addition to the above-mentioned effects.

[0025] <<2. First Embodiment>> Next, the first embodiment and its modified examples will be described with reference to FIGS.

[0026] <2-1. Wireless communication system configuration> 1 is a diagram showing an example of the configuration of a wireless communication system 1. For example, the wireless communication system 1 is a system that complies with the technical specifications of 3GPP (Third Generation Partnership Project). Specifically, the wireless communication system 1 may be a device that complies with the technical specifications of 5G. Naturally, the wireless communication system 1 is not limited to this example.

[0027] The wireless communication system 1 includes multiple wireless terminals 10-1 and 10-2 and a wireless communication device 20. In the example of Fig. 1, the wireless communication system 1 includes two wireless terminals, but the wireless communication system 1 may include one wireless terminal or three or more wireless terminals. Hereinafter, when there is no need to distinguish between the wireless terminals 10-1 and 10-2, they may be simply referred to as "wireless terminal 10."

[0028] The wireless terminal 10 may be referred to as a user equipment (UE) or a mobile station. For example, the wireless terminal 10 may be a mobile terminal such as a smartphone, a mobile phone, or a tablet. The wireless terminal 10 may also be a relay device having a relay function.

[0029] The wireless communication device 20 performs wireless communication with a plurality of wireless terminals 10-1 and 10-2. The wireless communication device 20 may be, for example, a node of a radio access network (RAN).

[0030] In the following, a link through which a signal is transmitted from the wireless communication device 20 to the wireless terminal 10 is referred to as a "downlink." A signal transmitted on the downlink is referred to as a "downlink signal." Furthermore, a link through which a signal is transmitted from the wireless terminal 10 to the wireless communication device 20 is referred to as an "uplink." A signal transmitted on the uplink is referred to as an "uplink signal."

[0031] <2-2. Wireless terminal configuration> The wireless terminals 10-1 and 10-2 have the same configuration. In the following, the configuration of the wireless terminal 10-1 will be described, and the description of the wireless terminal 10-2 will be omitted.

[0032] 2 is a block diagram showing an example of the configuration of wireless terminal 10-1. Wireless terminal 10-1 includes wireless communication section 210, storage section 220, and processing section 230.

[0033] The wireless communication unit 210 is an element that performs wireless communication with the wireless communication device 20. For example, the wireless communication unit 210 includes an antenna, a radio frequency (RF) circuit, and the like.

[0034] The storage unit 220 includes a volatile memory and a non-volatile memory. The volatile memory may include, for example, a random access memory (RAM). The non-volatile memory may include, for example, one or more of a read only memory (ROM), a hard disk drive (HDD), and a solid state drive (SSD). The non-volatile memory stores program code (instructions) for implementing various functions of the wireless terminal 10-1.

[0035] The processing unit 230 includes one or more processors. The one or more processors may include, for example, one or more of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a microcontroller. The processing unit 230 executes program codes stored in the storage unit 220 to realize various functions of the wireless terminal 10-1.

[0036] <2-3. Configuration of wireless communication device> As shown in Fig. 1, the wireless communication device 20 includes a control device 21 and multiple wireless devices 22-1 and 22-2. In the example of Fig. 1, the wireless communication device 20 includes two wireless devices 22-1 and 22-2, but the wireless communication device 20 may include one wireless device, or three or more wireless devices. Hereinafter, when there is no need to distinguish between the wireless devices 22-1 and 22-2, they may be simply referred to as "wireless device 22."

[0037] For example, the control device 21 may be a CU (Central Unit or Centralized Unit), a DU (Distributed Unit), or a RIC (RAN Intelligent Controller). The control device 21 may be configured to have some of the functions of an RU (Radio Unit or Remote Unit).

[0038] At least one of the radio devices 22-1 and 22-2 may be located at a location physically separated from the control device 21. For example, at least one of the radio devices 22-1 and 22-2 may be an RU (Radio Unit or Remote Unit), a TRP (Transmission and Reception point), or an AP (Access Point). Therefore, the radio communication device 20 may have a configuration of a Distributed Antenna Systems (DAS). Note that the radio devices 22-1 and 22-2 may have a configuration having some of the functions of an RU.

[0039] The control device 21 is connected to radio device 22-1 via a transmission path 23-1. The control device 21 communicates with radio device 22-1 via the transmission path 23-1. The control device 21 is connected to radio device 22-2 via a transmission path 23-2. The control device 21 communicates with radio device 22-2 via the transmission path 23-2.

[0040] The transmission paths 23-1 and 23-2 are media used for transmitting information, and may be, for example, optical fibers, metal cables, or wireless propagation paths.

[0041] For example, a radio over fiber (RoF) technology may be applied between the control device 21 and the wireless devices 22-1 and 22-2. In another example, a common public radio interface (CPRI) technology or an evolved common public radio interface (eCPRI) technology may be applied between the control device 21 and the wireless devices 22-1 and 22-2.

[0042] The control device 21 is connected to the plurality of radio devices 22-1 and 22-2 as described above, and is configured to communicate with the plurality of radio terminals 10-1 and 10-2 via the plurality of radio devices 22-1 and 22-2.

[0043] <2-4. Control device configuration> 3 is a block diagram showing an example of the configuration of the control device 21. The control device 21 includes a transmission line interface (IF) 310, a storage unit 320, and a processing unit 330.

[0044] The transmission path IF 310 includes an interface for communicating with the radio device 22-1 via the transmission path 23-1, and an interface for communicating with the radio device 22-2 via the transmission path 23-2.

[0045] The storage unit 320 includes a volatile memory and a non-volatile memory. The volatile memory may include, for example, a RAM. The non-volatile memory may include, for example, one or more of a ROM, a HDD, and an SSD. The non-volatile memory stores program code (instructions) for implementing various functions of the control device 21.

[0046] Furthermore, the nonvolatile memory stores information (data) used in the operation of the control device 21. Specifically, the nonvolatile memory stores a database (DB) 340.

[0047] The processing unit 330 includes one or more processors. The one or more processors may include, for example, one or more of a CPU, an MPU, and a microcontroller. The processing unit 330 executes program codes stored in the storage unit 320 to realize various functions of the control device 21.

[0048] The processing unit 330 has a baseband signal processing unit 331 as a functional block (functional module). The baseband signal processing unit 331 performs transmission processing and reception processing of baseband signals. The processing unit 330 may further include components other than the above-mentioned functional blocks. That is, the processing unit 330 can perform operations other than those performed by the above-mentioned functional blocks.

[0049] Note that the radio device 22 may have some of the functions of the baseband signal processing unit 331. In another example, another device (not shown) physically separated from the control device 21 may have some of the functions of the baseband signal processing unit 331. The detailed configuration of the baseband signal processing unit 331 will be described later.

[0050] <2-5. Wireless Device Configuration> The radio devices 22-1 and 22-2 have the same configuration. In the following, the configuration of the radio device 22-1 will be described, and the description of the radio device 22-2 will be omitted.

[0051] 4 is a block diagram showing an example of the configuration of the wireless device 22-1. The wireless device 22-1 includes a transmission path interface (IF) 410, a storage unit 420, a processing unit 430, and a wireless communication unit 440.

[0052] The transmission line IF 410 is an interface for communicating with the control device 21 via the transmission line 23-1.

[0053] The storage unit 420 includes a volatile memory and a non-volatile memory. The volatile memory may include, for example, a RAM. The non-volatile memory may include, for example, one or more of a ROM, a HDD, and an SSD. The non-volatile memory stores program code (instructions) for implementing various functions of the wireless device 22-1.

[0054] The processing unit 430 includes one or more processors. The one or more processors may include, for example, one or more of a CPU, an MPU, and a microcontroller. The processing unit 430 executes program codes stored in the storage unit 420 to realize various functions of the wireless device 22-1.

[0055] The wireless communication unit 440 is an element that performs wireless communication with the wireless terminal 10. The wireless communication unit 440 transmits a radio frequency signal to the wireless terminal 10 and receives a radio frequency signal from the wireless terminal 10. For example, the wireless communication unit 440 can be implemented by a plurality of antennas and a radio frequency (RF) circuit. Specifically, the wireless communication unit 440 includes a plurality of antennas (antenna elements) 441-1 to 441-N, where N is an integer equal to or greater than 2.

[0056] In this example, wireless communication unit 440 includes multiple antennas 441-1 to 441-N, but the configuration of wireless communication unit 440 is not limited to this example. Wireless communication unit 440 may include a single antenna capable of controlling the beam direction. For example, wireless communication unit 440 may include a directional antenna such as a lens antenna or a metamaterial.

[0057] The processing unit 430 has a signal processing unit 431 as a functional block (functional module). The signal processing unit 431 performs processing to convert a baseband signal into a radio frequency signal, and processing to convert a radio frequency signal into a baseband signal. In another example, the control device 21 may perform these processes.

[0058] Signal processing unit 431 controls the shape and direction (angle) of a beam formed by at least one of multiple antennas 441-1 to 441-N (i.e., performs beamforming). Specifically, signal processing unit 431 adjusts the amplitude and phase of a radio frequency signal. For this processing, control device 21 determines amplitude setting values ​​and phase setting values, and notifies signal processing unit 431 of these setting values. Note that the amplitude and phase adjustment may be performed on a baseband signal.

[0059] In this example, as shown in FIG. 1, radio device 22-1 can form multiple beams 1 to m. Identifiers are assigned in advance to each beam shape and direction. Hereinafter, these identifiers will be referred to as "beam numbers." For example, beam numbers 1 to m are assigned to beams 1 to m, respectively. Furthermore, radio device 22-2 can form multiple beams m+1 to n. Beam numbers m+1 to n are assigned to beams m+1 to n, respectively.

[0060] <2-6. Configuration of the baseband signal processing section> 5 is a block diagram showing an example of the configuration of the baseband signal processing unit 331 in the control device 21. The baseband signal processing unit 331 includes a transmission signal processing unit 510, a reception signal processing unit 520, a scheduling unit 530, and a beam management unit 540.

[0061] The transmission signal processing unit 510 generates a signal to be transmitted to the wireless terminal 10. The transmission signal processing unit 510 transmits the generated signal to the wireless device 22 via the transmission path IF310.

[0062] The received signal processing unit 520 receives the signal received by the radio device 22 via the transmission path IF 310 .

[0063] Radio device 22 receives the measurement results of the reception quality of the beam from radio terminal 10 and transmits the measurement results of the reception quality of the beam to reception signal processing unit 520. Reception signal processing unit 520 receives the measurement results of the reception quality of the beam from radio device 22. Reception signal processing unit 520 transmits the measurement results of the reception quality to beam management unit 540.

[0064] In this example, the reception quality is information measured in the radio terminal 10 when the radio device 22 transmits a downlink signal using a transmission beam. For example, the reception quality may be information indicating reception power (e.g., RSRP (Reference Signal Received Power)). The reception power is measured using, for example, a synchronization signal or a reference signal. The synchronization signal may be, for example, an NR (New Radio) SSS (Secondary Synchronization Signal). The reference signal may be, for example, a CSI-RS (Channel State Information-Reference Signal) or an NR PBCH-DMRS (Physical Broadcast Channel-Demodulation Reference Signal).

[0065] In another example, the reception quality may be information representing Reference Signal Received Quality (RSRQ), Signal to Noise Ratio (SNR), Signal to Interference Ratio (SIR), or Signal to Interference plus Noise Ratio (SINR).

[0066] Hereinafter, the measurement results of the reception quality of the beam will be simply referred to as "measurement results" for the sake of simplicity.

[0067] The scheduling unit 530 allocates radio resources used for communication with the wireless terminal 10. For example, the radio resources may include antennas, beams, frequencies, time, etc. Then, the scheduling unit 530 transmits the results of the allocation of the radio resources to the transmission signal processing unit 510 and the reception signal processing unit 520.

[0068] Furthermore, the scheduling unit 530 transmits information regarding the transmission beam used when transmitting a radio frequency signal to the wireless terminal 10, and information regarding the reception beam used when receiving a radio frequency signal from the wireless terminal 10, to the wireless device 22 (specifically, the signal processing unit 431) via the transmission path IF310.

[0069] In another example, the baseband signal processing unit 331 may control the beam. In this configuration, the scheduling unit 530 transmits information about the transmit beam to the transmit signal processing unit 510. The transmit signal processing unit 510 may control the transmit beam in accordance with this information. Furthermore, the scheduling unit 530 transmits information about the receive beam to the receive signal processing unit 520. The receive signal processing unit 520 may control the receive beam in accordance with this information.

[0070] The beam management unit 540 receives the measurement results from the received signal processing unit 520. The beam management unit 540 creates the DB 340 based on the measurement results. The DB 340 includes information indicating the relationships between multiple beams 1 to n for each of multiple propagation environments. The beam management unit 540 updates the DB 340 based on the measurement results. The beam management unit 540 uses the DB 340 to select at least one beam from the multiple beams 1 to n. The beam management unit 540 transmits information about the selected beam to the transmitted signal processing unit 510 or the scheduling unit 530. The details of the beam management unit 540 will be described later.

[0071] <2-7. Beam Control Unit Configuration> 6 is a block diagram showing an example of the configuration of the beam management unit 540 and an example of the configuration of the storage unit 320. The beam management unit 540 includes a measurement result acquisition unit 610, a database (DB) update unit 620, and a beam selection unit 630. The DB 340 includes a first database (DB) 341.

[0072] The measurement result acquisition unit 610 receives (acquires) the measurement result from the received signal processing unit 520. An example in which the wireless terminal 10-1 measures the reception quality of a beam will be described below. For example, the wireless device 22-1 transmits a reference signal to the wireless terminal 10-1. The wireless terminal 10-1 measures the reception quality of the reference signal for multiple beams selected (instructed) by the beam management unit 540 (specifically, the beam selection unit 630). The wireless terminal 10-1 transmits the measurement result to the wireless device 22-1. The measurement result includes information related to the reception quality of the multiple beams.

[0073] In this example, the wireless terminal 10-1 selects a predetermined number k1 of beams from among the measured beams in descending order of reception quality. Then, the wireless terminal 10-1 transmits (reports) information about the reception quality of the selected predetermined number k1 of beams as measurement results to the wireless device 22-1. For example, k1 is an integer equal to or greater than 2. The measurement result acquisition unit 610 transmits the measurement results to the DB update unit 620.

[0074] The DB update unit 620 receives the measurement results from the measurement result acquisition unit 610. The DB update unit 620 uses the measurement results to create and update the first DB 341. The DB update unit 620 may update the first DB 341 every time it receives a measurement result.

[0075] In another example, the DB update unit 620 may accumulate the measurement results until a predetermined period has elapsed, and update the first DB 341 each time the predetermined period has elapsed. In yet another example, if there is a wireless terminal 10 with small temporal fluctuations in reception quality, the DB update unit 620 may set a low frequency for reflecting the measurement results received from that wireless terminal 10 in the first DB 341. With this configuration, the first DB 341 is updated less frequently, thereby reducing the load on the update process.

[0076] The beam selection unit 630 uses the first DB 341 to perform a selection process to select at least one beam from the plurality of beams 1 to n.

[0077] The selection process includes a first selection process for selecting multiple beams to be used for measuring reception quality. Hereinafter, the multiple beams selected by the first selection process are referred to as "multiple beams Bma." The beam selection unit 630 transmits information about the multiple beams Bma to the transmission signal processing unit 510. As a result, the transmission signal processing unit 510 transmits reference signals to the target wireless terminal 10 using the multiple beams Bma. Then, the wireless terminal 10 measures reception quality for the multiple beams Bma.

[0078] The selection process includes a second selection process for selecting a beam to be used for communication with the wireless terminal 10. Hereinafter, the wireless terminal 10 to be communicated with is referred to as "wireless terminal 10a." Furthermore, the beam selected by the second selection process is referred to as "beam Bmb." The beam selection unit 630 transmits information about beam Bmb to the scheduling unit 530. The scheduling unit 530 assigns beam Bmb to the wireless terminal 10a. The wireless communication device 20 communicates with the wireless terminal 10a using beam Bmb.

[0079] <2-8. Configuration of the first database> 7 is a diagram conceptually showing an example of the data structure of a plurality of tables 700-1 to 700-n included in the first DB 341. Note that the format of the first DB 341 is not limited to a table format, and may be another format.

[0080] As in the above, an example will be described in which wireless terminal 10-1 reports the measurement results to wireless communication device 20. The measurement results reported from wireless terminal 10-1 include information about the beam (hereinafter referred to as the "first beam") having the highest reception quality among the predetermined number k1 of beams. For example, the measurement results include information about the difference between the reception quality of the first beam and the reception qualities of each of the other beams. Note that the measurement results may further include information indicating the respective values ​​of the reception quality of the predetermined number k1 of beams.

[0081] For example, it is considered that the propagation environment when the first beam is beam 1 is different from the propagation environment when the first beam is beam 2. Measurement results are organized for each propagation environment to select an appropriate beam. In the first DB341, the multiple propagation environments are distinguished based on the first beam. The first DB341 includes information (first information) that indicates the relationship between the difference in reception quality among multiple beams 1 to n for each of the multiple propagation environments in which the first beam is different from one another. Hereinafter, the relationship between the difference in reception quality may be referred to as the "first relationship." In this example, the first relationship is the difference from the reception quality of the first beam.

[0082] Furthermore, the first DB 341 includes information (second information) that indicates the relationship between the number of times of reporting reception quality among multiple beams 1 to n for each of multiple propagation environments in which the first beams are different from one another. Hereinafter, the relationship between the number of times of reporting reception quality may be referred to as the "second relationship." In this example, the second relationship indicates the magnitude relationship between the number of times of reporting among multiple beams 1 to n.

[0083] Specifically, the first DB 341 includes a plurality of tables 700-1 to 700-n. Table 700-1 includes a "first relationship and a second relationship" when the first beam is beam 1. On the other hand, table 700-n includes a "first relationship and a second relationship" when the first beam is beam n. Hereinafter, when there is no need to distinguish between the plurality of tables 700-1 to 700-n, they may be simply referred to as "table 700."

[0084] Since the structures of the tables 700-1 to 700-n are the same, the following description will be given of table 700-1.

[0085] Table 700-1 includes, as configuration items, beam number 710, difference in reception quality 720, and number of reports 730. These configuration items are stored in the first DB 341 in a state in which they are associated with each other.

[0086] As described above, the beam number 710 is information for identifying a beam.

[0087] In this example, the difference in reception quality 720 corresponds to the first relationship described above and represents the difference from the reception quality of the first beam (beam 1 in this example). In this example, the difference in reception quality 720 is expressed in decibels (dB). dB is a unit for expressing a relative difference in the strength (level) of a received signal. The unit dB is also used for the differences in reception quality in other DBs 342 to 344, which will be described later. Naturally, the difference in reception quality 720 is not limited to this and may be expressed in other units depending on the reception quality used. The difference in reception quality 720 may be the latest value, or may be a representative value calculated from the differences between two or more reception qualities. For example, the representative value may be an average value or a median value. The difference in reception quality 720 may be information (for example, rank information) indicating whether the difference from the reception quality is large or small.

[0088] Since the wireless terminal 10 reports the reception qualities of a predetermined number k1 of beams in descending order of reception quality, there is a possibility that there are beams for which the reception quality is not reported in the table 700-1. In this case, the DB update unit 620 may set the difference in reception quality 720 of such beams to a value greater than the maximum value of the difference in reception quality 720 among the beams for which the reception quality has been reported.

[0089] The number of reports 730 corresponds to the second relationship described above and indicates the number of times the measurement result is reported. Specifically, the number of reports 730 indicates the number of times the first beam (beam 1) is included in the measurement result when the first beam is beam 1. The number of reports 730 may be a cumulative value or an average value of cumulative values ​​over a certain period of time. The number of reports 730 is not limited to a numerical value indicating the number of times, and may be information indicating whether the number of times is high or low (for example, rank information).

[0090] <2-9. Example of operation of beam selection unit> Next, the operation of the beam selection unit 630 will be described. As described above, the first DB 341 includes a plurality of tables 700-1 to 700-n corresponding to a plurality of propagation environments. The beam selection unit 630 selects one table 700 corresponding to the current propagation environment based on the current communication status with the wireless terminal 10. The beam selection unit 630 performs the selection process using the difference in reception quality 720 (first relationship) or the number of reports 730 (second relationship) included in the selected table 700.

[0091] Next, the first selection process and the second selection process will be described in detail.

[0092] (1) First selection process Here, an example will be described in which the beam selection unit 630 selects a plurality of beams Bma whose reception quality is to be measured by the wireless terminal 10-1.

[0093] In this example, the beam selection unit 630 executes the first selection process at the following first to third points in time. First time point: the time point when the wireless terminal 10-1 initially connects to a cell covered by the wireless communication device 20. Second point in time: the point in time when the beam used for communication with the wireless terminal 10-1 is changed. The second point in time may be, for example, the point in time when the beam Bmb described above is determined. Third point: The point when the first DB341 was updated.

[0094] The following describes, as an example, the processing content at the first point in time. At the first point in time, the beam selection unit 630 acquires the beam number used when the wireless terminal 10-1 initially connected to the cell covered by the wireless communication device 20. For example, the beam selection unit 630 can acquire information on the beam number from a component of the baseband signal processing unit 331 (for example, the received signal processing unit 520 or the beam management unit 540).

[0095] For example, assume that the wireless terminal 10-1 initially connects to a cell using beam 1. In this case, the beam selection unit 630 acquires information on beam number 1. The beam selection unit 630 selects multiple beams Bma that have reception qualities that are little different from the reception quality of the currently used beam (i.e., beam 1). This is for the following reason: A beam that has reception qualities that are little different from the reception quality of beam 1 is likely to have a coverage area that is close to or adjacent to beam 1. Therefore, it can be expected that a relatively high reception quality will be measured.

[0096] Specifically, the beam selection unit 630 regards the currently used beam (i.e., beam 1) as the first beam and selects one table 700 corresponding to the current propagation environment. In this example, the beam selection unit 630 refers to table 700-1 when the first beam is beam 1. The beam selection unit 630 selects a predetermined number k2 of beams in table 700-1 in order of smallest difference 720 in reception quality as multiple beams Bma. k2 is an integer equal to or greater than 2.

[0097] According to this configuration, the beam selection unit 630 can select, as the beams Bma, multiple beams whose reception quality is smaller than that of beam 1. Therefore, when the wireless terminal 10-1 measures the reception quality of the multiple beams Bma, the reception quality of one or more of the multiple beams Bma is likely to satisfy the above-mentioned predetermined level. Therefore, it is possible to avoid beam failure. In other words, it is possible to avoid disconnection of communication between the wireless terminal 10-1 and the wireless communication device 20.

[0098] In another example, the beam selector 630 may select a predetermined number k2 of beams in the table 700-1 in descending order of the number of reports 730 as the beams Bma. A beam with a large number of reports 730 indicates that it is frequently included together with the first beam (in this example, beam 1) in the measurement results. The reception quality of such a beam may differ little from the reception quality of the first beam. In other words, a beam with a large number of reports 730 is likely to have a coverage area close to or adjacent to the first beam. Therefore, it is expected that a relatively high reception quality will be measured. As described above, it is possible to avoid beam obstruction. That is, it is possible to avoid disconnection of communication between the wireless terminal 10-1 and the wireless device 22.

[0099] (2) Second selection process Here, an example will be described in which the radio communication device 20 communicates with a plurality of radio terminals 10-1 and 10-2, and the beam selection unit 630 selects the beam Bmb to be used for communication with the radio terminal 10-2.

[0100] The beam selection unit 630 obtains information on the currently used (currently assigned) beam number from the scheduling unit 530. For example, assume that the wireless communication device 20 is communicating with the wireless terminal 10-1 using beam 1. In this case, the beam selection unit 630 obtains information on beam number 1. The beam selection unit 630 selects, as beam Bmb, a beam having a reception quality that is significantly different from the reception quality of the currently used beam (i.e., beam 1). This is for the following reason: A beam having a reception quality that is significantly different from the reception quality of beam 1 is likely to have a coverage area that is far from the coverage area of ​​beam 1. Therefore, it is expected that interference with beam 1 will be reduced.

[0101] Specifically, the beam selection unit 630 regards the currently used beam (i.e., beam 1) as the first beam and selects one table 700 corresponding to the current propagation environment. In this example, the beam selection unit 630 refers to table 700-1 when the first beam is beam 1. The beam selection unit 630 selects, as beam Bmb, a beam in table 700-1 for which the difference 720 in reception quality is equal to or greater than a predetermined first threshold Th1.

[0102] According to this configuration, beam Bmb is likely to have a coverage area that is far from the coverage area of ​​the first beam (in this example, beam 1). When the wireless communication device 20 communicates with the wireless terminal 10-2 using beam Bmb, interference with beam 1 that is currently being used can be reduced.

[0103] If the wireless communication device 20 is currently using multiple beams, the beam selection unit 630 may regard each of the multiple beams as a first beam and refer to multiple tables 700. The beam selection unit 630 may select, as beam Bmb, a beam for which the difference 720 in reception quality in each of the multiple tables 700 is equal to or greater than a predetermined first threshold value Th1.

[0104] Furthermore, the beam selection unit 630 may select beam Bmb as follows: The beam selection unit 630 selects, in table 700-1, a beam for which the difference in reception quality 720 is equal to or greater than a predetermined first threshold Th1 as beam candidate Bmb'. Here, it is assumed that beam candidate Bmb' is beam n. In this case, the beam selection unit 630 refers to table 700-n when the first beam is beam candidate Bmb' (i.e., beam n). If, in table 700-n, the difference in reception quality 720 for beam 1 is equal to or greater than a predetermined first threshold Th1, the beam selection unit 630 determines beam candidate Bmb' (i.e., beam n) as beam Bmb. This configuration can further enhance the effect of reducing interference with beam 1 currently being used.

[0105] In yet another example, the beam selector 630 may select as beam Bmb a beam in table 700-1 whose report count 730 is smaller than a predetermined second threshold Th2. A beam with a small report count 730 indicates that the beam is included less frequently together with the first beam (in this example, beam 1) in the measurement results. Such a beam is likely to have a coverage area far from the coverage area of ​​the first beam. With this configuration, when the wireless communication device 20 communicates with the wireless terminal 10-2 using beam Bmb, interference with the currently used beam 1 can be reduced.

[0106] <2-10. Processing flow> Next, the flow of processing in the control device 21 will be described with reference to FIGS.

[0107] 8 is a flowchart showing an example of the flow of a process for updating the first DB 341. The measurement result acquisition unit 610 acquires the measurement results (801). The measurement result acquisition unit 610 transmits the measurement results to the DB update unit 620. The DB update unit 620 updates the first DB 341 using the measurement results (802).

[0108] FIG. 9 is a flowchart showing an example of the flow of the first selection process. The beam selection unit 630 executes the flowchart of FIG. 9 at a first time point. The beam selection unit 630 acquires the beam number used when the wireless terminal 10 initially connected to a cell covered by the wireless communication device 20 (901). Next, the beam selection unit 630 refers to the first DB 341 (902). Specifically, the beam selection unit 630 considers the beam corresponding to the beam number acquired in step 901 to be the first beam and refers to the first DB 341. The beam selection unit 630 then refers to the table 700 for when the first beam is the beam corresponding to the beam number acquired in step 901. Next, the beam selection unit 630 selects multiple beams Bma from the table 700 referenced in step 902 as described above (903). Then, the beam selection unit 630 transmits information about the multiple beams Bma to the transmission signal processing unit 510 (904).

[0109] Furthermore, the beam selection unit 630 executes the flowchart of Fig. 9 at a second time point. For example, the beam selection unit 630 may execute the flowchart of Fig. 9 after executing the flowchart of Fig. 10, which will be described later. In this case, the beam selection unit 630 acquires information about beam Bmb in step 901. Then, in step 902, the beam selection unit 630 assumes that the beam to be used next (i.e., beam Bmb) is the first beam, and selects one table 700 corresponding to the current propagation environment. Specifically, the beam selection unit 630 refers to the table 700 when the first beam is beam Bmb. The subsequent processing is the same as that described above.

[0110] Furthermore, the beam selection unit 630 executes the flowchart of Fig. 9 at a third point in time. In this case, the beam selection unit 630 acquires the currently used beam number from the scheduling unit 530 in step 901. The subsequent processing is the same as that described above.

[0111] 10 is a flowchart showing an example of the flow of the second selection process. The beam selection unit 630 acquires the currently assigned beam number from the scheduling unit 530 (1001). Next, the beam selection unit 630 refers to the first DB 341 (1002). Specifically, the beam selection unit 630 considers the beam corresponding to the beam number acquired in step 1001 to be the first beam and refers to the first DB 341. The beam selection unit 630 then refers to the table 700 for when the first beam is the beam corresponding to the beam number acquired in step 1001. Next, the beam selection unit 630 selects the beam Bmb from the table 700 referenced in step 1002 as described above (1003). Then, the beam selection unit 630 transmits information about the beam Bmb to the scheduling unit 530 (1004).

[0112] <2-11.Effects> The above configuration has the following advantages: The control device 21 uses the measurement results to update the first DB 341. The control device 21 executes the first selection process and the second selection process using the first DB 341, and can select a beam suitable for the current propagation environment.

[0113] For example, Non-Patent Document 1 describes a method for selecting a beam so as to reduce interference between TRPs. In the method described in Non-Patent Document 1, the position of a wireless terminal is estimated in an environment where there are no obstacles between the TRP and the wireless terminal. Then, a beam is selected using the estimated position of the wireless terminal. Therefore, in the method described in Non-Patent Document 1, there is a possibility that a beam cannot be appropriately selected in an environment where there are obstacles between the TRP and the wireless terminal.

[0114] In contrast, as described above, the first DB 341 includes information on the first relationship (difference in reception quality 720) and the second relationship (number of reports 730) for each of a plurality of propagation environments in which the first beam differs from one another. The control device 21 selects one propagation environment (i.e., table 700) corresponding to the current propagation environment from among the plurality of propagation environments, and selects multiple beams Bma using the first relationship (difference in reception quality 720) or the second relationship (number of reports 730) in the selected propagation environment (table 700). That is, the control device 21 selects multiple beams Bma in consideration of the propagation environment, the reception quality of the beams, and the like. Therefore, even in an environment where there is an obstacle between the wireless terminal 10 and the wireless devices 22-1 and 22-2, it is possible to appropriately select multiple beams Bma for measuring the reception quality of the beams. As a result, it is possible to avoid disconnection of communication between the wireless terminal 10 and the wireless communication device 20.

[0115] Similarly, the control device 21 selects one propagation environment (i.e., table 700) corresponding to the current propagation environment from among a plurality of propagation environments, and selects beam Bmb using the first relationship (difference in reception quality 720) or the second relationship (number of reports 730) in the selected propagation environment (table 700). The control device 21 can select a beam that can reduce interference with the currently used beam as beam Bmb.

[0116] <2-12. Variations> The technology according to the present disclosure is not limited to the above-described embodiment. Two or more aspects arbitrarily selected from the above-described embodiment and the following modifications may be combined as appropriate as long as they are not mutually contradictory.

[0117] (1) Variation 1 The received signal processing unit 520 may measure the reception quality of the received beam based on the received uplink signal. In this configuration, the received signal processing unit 520 measures the reception quality of the reference signal received by the radio device 22. The received signal processing unit 520 transmits the measurement result to the measurement result acquisition unit 610. The beam selection unit 630 transmits information on the multiple beams Bma to the received signal processing unit 520. Then, the received signal processing unit 520 measures the reception quality of the reference signal received by the multiple beams Bma.

[0118] (2) Variation 2 In the second selection process, the beam selector 630 may select one or more beams that should not be used for communication with the wireless terminal 10 (i.e., that should not be assigned to the wireless terminal 10) and transmit information about the one or more beams to the scheduler 530. In this configuration, the beam selector 630 may select, as beam Bmb, a beam for which the difference in reception quality 720 is less than a predetermined third threshold Th3 in the table 700 corresponding to the currently assigned beam. In another example, the beam selector 630 may select, as beam Bmb, a beam for which the number of reports 730 is equal to or greater than a predetermined fourth threshold Th4.

[0119] (3) Variation 3 The beam selection unit 630 may predict whether the first beam will be switched based on temporal fluctuations in the reception quality of the beams. In this case, the beam selection unit 630 may perform the first selection process and the second selection process based on the above prediction. For example, it is assumed that the beam selection unit 630 predicts that the first beam will be switched from beam 1 to beam 2 based on the reception quality of multiple beams included in the measurement results. In this case, the beam selection unit 630 may perform the first selection process and the second selection process by referring to table 700-2 corresponding to beam 2. This configuration makes it possible to avoid a deterioration in communication quality that may occur when switching beams.

[0120] (4) Variation 4 The configuration of DB 340 is not limited to the above example (first DB 341). In table 700 of first DB 341, one of difference in reception quality 720 and number of reports 730 may be omitted.

[0121] Furthermore, the table 700 may include information for identifying the radio device 22 as an additional configuration item. In this case, the beam selection unit 630 may perform the first selection process as follows. For example, assume that the radio terminal 10-1 initially connects to the cell of the radio device 22-1 using beam 1. The beam selection unit 630 may select multiple beams Bma so that the multiple beams Bma include multiple beams corresponding to the radio devices 22-1 and 22-2. That is, the beam selection unit 630 may select multiple beams Bma so that at least one of beams 1 to m and at least one of beams m+1 to n are included in the multiple beams Bma. With this configuration, even if communication between the radio terminal 10-1 and the radio device 22-1 is disconnected, the radio terminal 10-1 can smoothly switch to the radio device 22-2.

[0122] (5) Variation 5 The control device 21 may measure the reception quality for the purpose of updating the DB 340 in order to improve the accuracy of the DB 340. In this case, the DB update unit 620 may select a wireless terminal 10 that has little effect on communication as the wireless terminal for measurement. Hereinafter, such a wireless terminal for measurement is referred to as "wireless terminal 10b."

[0123] For example, the DB update unit 620 may select a wireless terminal 10 with no communication data volume (or a relatively small communication data volume) as the wireless terminal 10b. In another example, the DB update unit 620 may select a wireless terminal 10 with a slow moving speed or a wireless terminal 10 in a stationary state as the wireless terminal 10b. For these wireless terminals, it is assumed that handover and beam switching are unlikely to occur and there is little need to measure reception quality. The DB update unit 620 may select such a wireless terminal 10 as the wireless terminal 10b and cause the wireless terminal 10b to measure reception quality for the purpose of updating the DB 340.

[0124] (6) Variation 6 The DB update unit 620 may select a beam for updating the DB 340 to improve the accuracy of the DB 340. Specifically, the DB update unit 620 may instruct the radio terminal 10 on the beam to be included in the measurement results. According to this configuration, the radio terminal 10 reports the reception quality of the instructed beam to the radio communication device 20 regardless of the reception quality. To achieve this, when multiple beams Bma are notified to the radio terminal 10, the DB update unit 620 may also transmit instruction information for instructing the radio terminal 10 on the reception quality of the beam to be included in the measurement results. The instruction information may be a control message or a flag. Furthermore, the DB update unit 620 may transmit the instruction information so that the reception qualities of multiple beams corresponding to the multiple radio devices 22-1 and 22-2 are included in the measurement results. That is, the DB update unit 620 may transmit the instruction information so that at least one of beams 1 to m and at least one of beams m+1 to n are included in the measurement results. In another example, the DB update unit 620 may transmit instruction information instructing to report the reception qualities of all of the multiple beams Bma, thereby enabling the DB update unit 620 to efficiently acquire the required measurement results.

[0125] (7) Variation 7 The DB 340 may store one or more of a second DB 342, a third DB 343, and a fourth DB 344 instead of or in addition to the first DB 341.

[0126] FIG. 11 is a diagram conceptually showing an example of the data structure of tables 1100-1 to 1100-s included in the second DB 342. As shown in FIG.

[0127] In the second DB 342, the multiple propagation environments are distinguished based on the first beam and the reception quality of the first beam. For example, a propagation environment in which the first beam is beam 1 and the reception quality of beam 1 is relatively poor is considered to be different from a propagation environment in which the first beam is beam 1 and the reception quality of beam 1 is relatively high. For example, if the reception quality of beam 1 is poor, the wireless terminal 10 may be located at the edge of the coverage area of ​​beam 1. On the other hand, if the reception quality of beam 1 is high, the wireless terminal 10 may be located near the center of the coverage area of ​​beam 1. The second DB 342 can also be said to be a database that reflects differences in the positional relationship between the wireless terminal 10 and the coverage area (i.e., differences in the propagation environment).

[0128] In this example, the reception quality of the first beam includes a first range R1, a second range R2, and a third range R3. The first range R1 is a range in which the reception quality value is less than a predetermined first value z1. The second range R2 is a range in which the reception quality value is equal to or greater than the first value z1 and less than a predetermined second value z2. The third range R3 is a range in which the reception quality value is equal to or greater than the second value z2.

[0129] In this example, the reception quality of the first beam is divided into three ranges, but this is not limiting and the reception quality of the first beam may be divided into two ranges, or into four or more ranges.

[0130] Specifically, the second DB 342 includes a plurality of tables 1100-1 to 1100-s. Hereinafter, when there is no need to distinguish between the plurality of tables 1100-1 to 1100-s, they may be simply referred to as "table 1100."

[0131] Since the multiple tables 1100-1 to 1100-s have the same structure, only table 1100-1 will be described below. Table 1100-1 is a table for the case where the first beam is beam 1 and the reception quality of beam 1 is in a first range R1.

[0132] Table 1100-1 includes, as its configuration items, a beam number 1110, a difference in reception quality 1120, and a number of reports 1130. These configuration items are stored in association with each other in second DB 342. The beam number 1110, the difference in reception quality 1120, and the number of reports 1130 are the same as the beam number 710, the difference in reception quality 720, and the number of reports 730 described above, respectively, and therefore description thereof will be omitted.

[0133] In this configuration, DB update section 620 updates a plurality of tables 1100-1 to 1100-s in accordance with the value of the reception quality of the first beam.

[0134] The beam selection unit 630 selects one propagation environment (i.e., table 1100) corresponding to the current propagation environment from among multiple propagation environments based on the first beam and the reception quality of the first beam determined from the measurement results acquired at the current time. The beam selection unit 630 performs the selection process using the first relationship (difference in reception quality 1120) or the second relationship (number of reports 1130) in the selected propagation environment (table 1100).

[0135] For example, the beam selection unit 630 executes the first selection process as follows: The beam selection unit 630 acquires the measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a first beam and the reception quality of the first beam from the measurement results. Assume that the first beam is beam 1 and the reception quality of beam 1 is in a first range R1. In this case, the beam selection unit 630 refers to table 1100-1 and selects multiple beams Bma as described above.

[0136] For example, the beam selection unit 630 performs the second selection process as follows. An example will be described in which the beam selection unit 630 selects a beam Bmb to be used for communication with the wireless terminal 10-2. Assume that the wireless communication device 20 is communicating with the wireless terminal 10-1 using beam 1. The beam selection unit 630 acquires measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a first beam and the reception quality of the first beam from the measurement results. If the first beam is beam 1 and the reception quality of beam 1 is in a first range R1, the beam selection unit 630 refers to table 1100-1 and selects beam Bmb as described above.

[0137] According to this configuration, the second DB 342 includes information on the first relationship and the second relationship for each range of reception quality of the first beam. Therefore, the second DB 342 reflects more propagation environments than the first DB 341. This can further improve the effect of appropriately selecting a beam.

[0138] FIG. 12 is a diagram conceptually showing an example of the data structure of a plurality of tables 1200-1 to 1200-t included in the third DB 343. As shown in FIG.

[0139] In the third DB 343, the multiple propagation environments are distinguished based on a first combination of beams. Here, the "first combination of beams" refers to a combination of a beam having the highest reception quality (referred to as the "first beam" as described above) and a beam having the second highest reception quality (referred to as the "second beam" hereinafter) among a predetermined number k1 of beams included in the measurement results. Hereinafter, the "first combination of beams" will be simply referred to as the "first combination."

[0140] For example, a propagation environment in which the first beam is beam 1 and the second beam is beam 2 is considered to be different from a propagation environment in which the first beam is beam 1 and the second beam is beam 3. The third DB 343 is a database that reflects such differences in propagation environments.

[0141] Specifically, the third DB 343 includes a plurality of tables 1200-1 to 1200-t. Hereinafter, when there is no need to distinguish between the plurality of tables 1200-1 to 1200-t, they may be simply referred to as "table 1200."

[0142] Since the structures of the tables 1200-1 to 1200-t are the same, only table 1200-1 will be described below. Table 1200-1 is a table for the case where the first combination is a combination of beam 1 and beam 2.

[0143] Table 1200-1 includes, as configuration items, a beam number 1210, a difference in reception quality 1220, and a number of reports 1230. These configuration items are stored in the third DB 343 in a state in which they are associated with each other.

[0144] The beam number 1210 and the number of reports 1230 are the same as the beam number 710 and the number of reports 730 described above, respectively, and therefore will not be described here.

[0145] The difference in reception quality 1220 may be the difference from the reception quality of a first beam. The difference in reception quality 1220 may be the difference from the reception quality of a second beam. The difference in reception quality 1220 may be the average value of the difference from the reception quality of the first beam and the difference from the reception quality of the second beam.

[0146] In this configuration, the DB update unit 620 acquires the measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a first combination from the measurement results. Then, the DB update unit 620 updates the table 1200 corresponding to the determined first combination.

[0147] The beam selection unit 630 selects one propagation environment (i.e., table 1200) that corresponds to the current propagation environment from among multiple propagation environments based on a first combination determined from measurement results acquired at the current time. The beam selection unit 630 performs selection processing using the first relationship (difference in reception quality 1220) or the second relationship (number of reports 1230) in the selected propagation environment (table 1200).

[0148] For example, the beam selection unit 630 executes the first selection process as follows: The beam selection unit 630 acquires the measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a first combination from the measurement results. Here, it is assumed that the first combination is a combination of beam 1 and beam 2. In this case, the beam selection unit 630 refers to table 1200-1 and selects multiple beams Bma as described above.

[0149] For example, the beam selection unit 630 performs the second selection process as follows. An example will be described in which the beam selection unit 630 selects a beam Bmb to be used for communication with the wireless terminal 10-2. It is assumed that the wireless communication device 20 is communicating with the wireless terminal 10-1 using beam 1. The beam selection unit 630 acquires measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a first combination from the measurement results. Here, it is assumed that the first combination is a combination of beam 1 and beam 2. In this case, the beam selection unit 630 refers to table 1200-1 and selects beam Bmb as described above. Note that even if beam 2 is currently being used and the first combination is a combination of beam 1 and beam 2, the beam selection unit 630 still refers to table 1200-1.

[0150] According to this configuration, the third DB 343 includes information on the first relationship and the second relationship for each first combination. Therefore, the third DB 343 reflects more propagation environments than the first DB 341. This can further improve the effect of appropriately selecting beams.

[0151] The third DB 343 may be referred to when switching beams (for example, at the time of handover). For example, when the beam used for communication with the wireless terminal 10-1 is switched from beam 1 to beam 2, the beam selection unit 630 may refer to the table 1200-1 and select multiple beams Bma as described above.

[0152] Although a combination of two beams is used in the third DB 343, the configuration is not limited to this. The third DB 343 may be created to include information on the first relationship and the second relationship for each combination of three or more beams.

[0153] 13 is a diagram conceptually showing an example of the data structure of tables 1300-1 to 1300-u included in the fourth DB 344. In this example, it is assumed that the control device 21 is connected to three or more wireless devices 22.

[0154] In the fourth DB 344, the multiple propagation environments are distinguished based on a second combination of beams and a third combination of wireless devices. Here, the "third combination of wireless devices" refers to a "combination of a first wireless device and a second wireless device" included among three or more wireless devices 22. The first wireless device is the wireless device 22 that forms the third beam having the highest reception quality in the first beam set. The second wireless device is the wireless device 22 that forms the fourth beam having the highest reception quality in the second beam set. The first beam set is a set of all beams included in the measurement results. The second beam set is a set obtained by removing the beam formed by the first wireless device from the first beam set. Furthermore, the "second combination of beams" here refers to a combination of a third beam and a fourth beam. Hereinafter, the "second combination of beams" will be simply referred to as the "second combination," and the "third combination of wireless devices" will be simply referred to as the "third combination." The fourth DB 344 can also be said to be a database that reflects the difference in propagation environment from the viewpoint of reception quality from two wireless devices.

[0155] Specifically, the fourth DB 344 includes a plurality of tables 1300-1 to 1300-u. Hereinafter, when there is no need to distinguish between the plurality of tables 1300-1 to 1300-u, they may be simply referred to as "tables 1300."

[0156] Since the structures of the multiple tables 1300-1 to 1300-u are the same, only table 1300-1 will be described below. Table 1300-1 is a table for the case where "the second combination is a combination of beam 1 and beam m+1, and the third combination is a combination of radio equipment 22-1 and radio equipment 22-2."

[0157] Table 1300-1 includes, as configuration items, a beam number 1310, a difference in reception quality 1320, and a number of reports 1330. These configuration items are stored in the fourth DB 344 in a state in which they are associated with each other.

[0158] The beam number 1310 and the number of reports 1330 are the same as the beam number 710 and the number of reports 730 described above, respectively, and therefore will not be described here.

[0159] The difference in reception quality 1320 may be the difference from the reception quality of the third beam. The difference in reception quality 1320 may be the difference from the reception quality of the fourth beam. The difference in reception quality 1320 may be the average value of the difference from the reception quality of the third beam and the difference from the reception quality of the fourth beam.

[0160] In this configuration, the DB update unit 620 acquires the measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines the second combination and the third combination from the measurement results. Then, the DB update unit 620 updates the table 1300 corresponding to the determined "second combination and third combination."

[0161] The beam selection unit 630 selects one propagation environment (i.e., table 1300) that corresponds to the current propagation environment from among multiple propagation environments based on the "second combination and third combination" determined from the measurement results currently acquired. The beam selection unit 630 performs selection processing using the first relationship (difference in reception quality 1320) or the second relationship (number of reports 1330) in the selected propagation environment (table 1300).

[0162] For example, the beam selection unit 630 executes the first selection process as follows: The beam selection unit 630 acquires the measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines the second combination and the third combination from the measurement results. Here, it is assumed that the second combination is a combination of beam 1 and beam m+1, and the third combination is a combination of radio equipment 22-1 and radio equipment 22-2. In this case, the beam selection unit 630 refers to table 1300-1 and selects multiple beams Bma as described above.

[0163] For example, the beam selection unit 630 performs the second selection process as follows. An example will be described in which the beam selection unit 630 selects a beam Bmb to be used for communication with the wireless terminal 10-2. It is assumed that the wireless communication device 20 is communicating with the wireless terminal 10-1 using beam 1. The beam selection unit 630 acquires measurement results from the measurement result acquisition unit 610. The beam selection unit 630 determines a second combination and a third combination from the measurement results. Here, it is assumed that the second combination is a combination of beam 1 and beam m+1, and the third combination is a combination of wireless device 22-1 and wireless device 22-2. The beam selection unit 630 refers to table 1300-1 and selects beam Bmb as described above.

[0164] According to this configuration, the fourth DB 344 includes information on the first relationship and the second relationship for each second combination and for each third combination. The fourth DB 344 reflects more propagation environments than the first DB 341. This can further improve the effect of appropriately selecting beams.

[0165] When multiple wireless devices 22-1 and 22-2 are communicating with the same wireless terminal 10, the beam selection unit 630 may refer to the fourth DB 344. For example, when wireless device 22-1 is communicating with wireless terminal 10-1 using beam 1 and wireless device 22-2 is communicating with wireless terminal 10-1 using beam m+1, the beam selection unit 630 may refer to table 1300-1 and perform the first selection process or the second selection process.

[0166] Note that there may be combinations of beams that are unlikely to be established as the "second combination." The DB update unit 620 may delete information corresponding to such combinations of beams in advance from the fourth DB 344. The DB update unit 620 may delete information corresponding to such combinations of beams according to the difference 1320 in reception quality and the number of reports 1330.

[0167] Although the fourth DB 344 uses a combination of two beams and a combination of two wireless devices, the configuration is not limited to this. The fourth DB 344 may be created to include information on the first relationship and the second relationship for each combination of three or more beams and for each combination of three or more wireless devices 22.

[0168] (8) Variation 8 Although DB340 records the number of times that measurement results have been reported, this configuration is not limiting. DB340 may also record the number of times that reception quality has been measured, or the number of times that measurements have been performed but not reported to the control device 21. The beam selector 630 may use this information to distinguish between beams that have been measured a small number of times and beams that were not included in the measurement results because of their low reception quality. This can further improve the effectiveness of appropriately selecting beams.

[0169] (9) Variation 9 The DB update unit 620 may create the DB 340 using machine learning. For example, clustering, which is one type of unsupervised learning, may be used. The DB update unit 620 may group measurement results of similar propagation environments using clustering, and create information representing a first relationship or a second relationship of reception quality between multiple beams 1 to n for each of the multiple groups (propagation environments). The grouping may be performed based on the similarity of the measurement results. For example, the similarity of the measurement results may be determined by defining an n-dimensional vector having the measurement results of multiple beams 1 to n as elements and using the cosine similarity of the vector. Alternatively, the Euclidean distance of normalized vectors may be used as the similarity of the measurement results. Furthermore, the beam selection unit 630 may calculate the similarity between the currently acquired measurement result and the average measurement result of each of the multiple groups (propagation environments), and perform selection processing using the first relationship or the second relationship of the group (propagation environment) with the highest similarity. When calculating the average measurement results for each of multiple groups (propagation environments), the measurement results may be normalized before averaging. This configuration allows the creation of DB 340 that accurately reflects differences in the propagation environments.

[0170] As another example of machine learning, a neural network may be used. The DB update unit 620 may use the neural network to create a database that outputs the priority (evaluation value) of each beam according to the combination of beams (first beam and second beam) and the difference in reception quality, etc. Measurement results of reception quality may be used as training data for configuring the neural network. This is expected to improve the accuracy of the DB 340.

[0171] (10) Variation 10 The control device 21 may change the number of beams and the beam shape according to the time period and location. In the above example, the control device 21 can form beams 1 to n, but may reduce the number of beams during time periods with low communication traffic. For example, the control device 21 may reduce the number of beams in an office district at night or in a residential district at night. Furthermore, the control device 21 may change the shape of the beams so as to reduce the coverage area during time periods with low communication traffic. In this case, the control device 21 may determine whether the communication traffic is low based on the number of wireless terminals connected to the multiple wireless devices 22-1 and 22-2.

[0172] Furthermore, the control device 21 may create the DB 340 according to time period and location. For example, the amount of communication in an office district at night is smaller than the amount of communication in an office district during the day. Therefore, the propagation environment in an office district at night is considered to be different from the propagation environment in an office district during the day. The control device 21 may create a first DB 341 to a fourth DB 344 to be used in a first time period (e.g., daytime) and a first DB 341 to a fourth DB 344 to be used in a second time period (e.g., nighttime).

[0173] (11) Variation 11 A plurality of radio devices 22-1 and 22-2 may communicate with the same radio terminal 10. In this case, the beam selector 630 may refer to two tables included in the DB 340. For example, assume that the beam selector 630 refers to the first DB 341 in the first selection process. The beam selector 630 refers to the table 700 corresponding to the beam used by the radio device 22-1 and performs the first selection process as described above. Furthermore, the beam selector 630 refers to the table 700 corresponding to the beam used by the radio device 22-2 and performs the first selection process as described above. This configuration makes it possible to measure the reception quality of the beams formed by the plurality of radio devices 22-1 and 22-2. As a result, improvement in communication quality can be expected. Note that if there is no selectable beam, the beam selector 630 may transmit a response indicating that beam assignment is not possible.

[0174] Furthermore, when multiple radio devices 22-1 and 22-2 communicate with the same radio terminal 10, the beam selection unit 630 may select as beam Bmb the beam having the highest reception quality determined from the measurement results currently acquired for each of the multiple radio devices 22-1 and 22-2. That is, the beam selection unit 630 may select as beam Bmb the beam having the highest reception quality among beams 1 to m, and may also select as beam Bmb the beam having the highest reception quality among beams m+1 to n.

[0175] <<3. Second Embodiment>> Next, a second embodiment will be described with reference to Figures 14 and 15. The first embodiment described above is a specific embodiment, but the second embodiment is a more generalized embodiment.

[0176] <3-1. Configuration of the control device> 14 is a diagram showing an example of the configuration of the control device 1400. The control device 1400 includes an acquisition unit 1410, an update unit 1420, and a selection unit 1430.

[0177] The above-described functional modules 1410, 1420, and 1430 included in the control device 1400 may be implemented by at least one of one or more processors and a memory. The one or more processors may include, for example, one or more of a CPU, an MPU, and a microcontroller. The memory may include a volatile memory and a non-volatile memory. The memory may store program code (instructions). The one or more processors may implement functions of the control device 1400 (e.g., the acquisition unit 1410, the update unit 1420, and the selection unit 1430) by executing the program code stored in the memory.

[0178] The acquisition unit 1410 acquires measurement results of reception quality for multiple beams. The update unit 1420 updates a database (DB) 1421 based on the measurement results. For example, the DB 1421 is stored in the memory described above. The DB 1421 includes information indicating the relationship between multiple beams for each of multiple propagation environments. The selection unit 1430 executes a selection process to select a beam using the database 1421.

[0179] The acquiring unit 1410 may operate in the same manner as the above-described measurement result acquiring unit 610. The updating unit 1420 may operate in the same manner as the above-described DB updating unit 620. The DB 1421 may include at least one of the first DB 341 to the fourth DB 344, similar to the above-described DB 340. The selecting unit 1430 may operate in the same manner as the above-described beam selecting unit 630.

[0180] <3-2. Processing flow> FIG. 15 is a flowchart illustrating an example of the processing flow of the control device 1400.

[0181] The acquisition unit 1410 acquires measurement results of reception quality for a plurality of beams (1501). Update section 1420 The DB 1421 is updated based on the measurement results (1502). The selection unit 1430 executes a selection process to select a beam using the DB 1421 (1503).

[0182] According to the above configuration, the control device 1400 can appropriately select a beam.

[0183] <<4. Other Embodiments>> It should be noted that the above-described embodiment and modified examples are merely examples, and the scope of the technical idea of ​​the present disclosure is not limited to the above-described configurations. Other aspects conceivable within the scope of the technical idea of ​​the present disclosure are also included in the scope of the present disclosure.

[0184] The process steps shown in the flowcharts do not necessarily have to be performed in the order shown. The process steps may be performed in an order different from that shown, two or more process steps may be performed in parallel, some process steps may be omitted, and additional process steps may be added.

[0185] The functions of the devices (wireless terminal 10, wireless communication device 20, and control device 1400) described in this specification may be realized by software, hardware, or a combination of software and hardware. Program code (instructions) constituting the software may be stored, for example, in a computer-readable recording medium inside or outside each device, and may be loaded into memory and executed by a processor at runtime. Alternatively, a non-transitory computer-readable recording medium on which the program code is recorded may be provided.

[0186] For example, FIG. 16 is a diagram illustrating a combination of software and hardware that realizes the functions of the control device 1400. The information processing device 1600 includes a non-transitory recording medium 1610, a memory 1620, and a processor 1630. These components are connected to one another via an internal bus. The non-transitory recording medium 1610 stores program code that realizes the function modules 1410 to 1430 of the control device 1400. The program code that realizes the function modules 1410 to 1430 is read into the memory 1620. The processor 1630 reads the program code from the memory 1610. 6 The wireless terminal 10 and the wireless communication device 20 execute the program code read out by the non-transitory storage medium 1410 to 1430, thereby performing the processing of the functional modules 1410 to 1430. Similarly, the wireless terminal 10 and the wireless communication device 20 may also be realized by a combination of a non-transitory storage medium, a memory, and a processor.

[0187] Some or all of the above-described embodiments and modified examples can be described as, but are not limited to, the following supplementary notes.

[0188] (Appendix 1) an acquisition unit that acquires measurement results including information about the reception quality of a plurality of beams; an updating unit that updates a database including information representing a relationship between the plurality of beams for each of a plurality of propagation environments based on the measurement results; a selection unit that executes a selection process for selecting a beam using the database; A control device comprising:

[0189] (Appendix 2) The selection unit selecting the relationship corresponding to a current propagation environment from the information representing the relationship; performing the selection process using the selected relationship; 10. The control device of claim 1.

[0190] (Appendix 3) In the information representing the relationship, the plurality of propagation environments are distinguished based on a first beam having the highest reception quality at the time when the measurement result is acquired, The selection unit regards a beam that is currently being used or that should be used next as the first beam and selects the relationship that corresponds to the current propagation environment. 3. The control device according to claim 2.

[0191] (Appendix 4) In the information representing the relationship, the plurality of propagation environments are distinguished based on a first beam having the highest reception quality at the time when the measurement result is acquired and the reception quality of the first beam, The selection unit selects the relationship corresponding to the current propagation environment based on the first beam and the reception quality of the first beam determined from the measurement result acquired at the current time. 3. The control device according to claim 2.

[0192] (Appendix 5) In the information representing the relationship, the plurality of propagation environments are distinguished based on a first combination of beams; the first combination includes at least a first beam having the highest reception quality at the time when the measurement result is obtained and a second beam having the second highest reception quality at the time when the measurement result is obtained; The selection unit selects the relationship corresponding to the current propagation environment based on the first combination determined from the measurement results currently acquired. 3. The control device according to claim 2.

[0193] (Appendix 6) the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; In the information representing the relationship, the plurality of propagation environments are distinguished based on a second combination of beams and a third combination of the wireless devices; The third combination is a first radio device included in the plurality of radio devices, the first radio device forming a third beam having the highest reception quality in the first beam set; a second radio device included in the plurality of radio devices, the second radio device forming a fourth beam having the highest reception quality in the second beam set; At least the first beam set is a set of all beams included in the measurement result; the second beam set is a set obtained by deleting the beam formed by the first wireless device from the first beam set; the second combination includes at least the third beam and the fourth beam; The selection unit selects the relationship corresponding to the current propagation environment based on the second combination and the third combination determined from the measurement results currently acquired. 3. The control device according to claim 2.

[0194] (Appendix 7) In the information representing the relationship, the plurality of propagation environments are distinguished based on a similarity of the measurement results, the selection unit selects the relationship corresponding to the current propagation environment based on the similarity between the measurement result currently acquired and an average measurement result of each of the plurality of propagation environments. 3. The control device according to claim 2.

[0195] (Appendix 8) the similarity includes a cosine similarity of a vector having the reception qualities of the plurality of beams as elements. 8. The control device according to claim 7.

[0196] (Appendix 9) the information representing the relationship includes first information representing a first relationship of the difference in reception quality between the plurality of beams. 9. The control device according to any one of appendices 1 to 8.

[0197] (Appendix 10) the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; The selection unit selecting the first relationship corresponding to a current propagation environment in the first information; performing the selection process using the selected first relationship; The selection process includes: a first selection process for selecting a beam to be used for measuring the reception quality; a second selection process for selecting a beam to be used for communication with the wireless terminal; including at least one of 10. The control device according to claim 9.

[0198] (Appendix 11) the first selection process includes selecting a predetermined number of beams in order of smallest difference from a beam currently being used or to be used next; 11. The control device of claim 10.

[0199] (Appendix 12) the first selection process includes selecting the predetermined number of beams such that the predetermined number of beams includes a plurality of beams corresponding to two or more wireless devices among the plurality of wireless devices; 12. The control device of claim 11.

[0200] (Appendix 13) When the control device communicates with the plurality of wireless terminals, the second selection process includes selecting a beam whose difference from a currently used beam is greater than a predetermined first threshold. 11. The control device of claim 10.

[0201] (Appendix 14) When the control device communicates with the same wireless terminal via the plurality of wireless devices, the second selection process includes selecting, in each of the plurality of wireless devices, a beam having the highest reception quality determined from the measurement results currently acquired. 11. The control device of claim 10.

[0202] (Appendix 15) the information representing the relationship includes second information representing a second relationship between the number of reports of the reception quality among the plurality of beams. 9. The control device according to any one of appendices 1 to 8.

[0203] (Appendix 16) the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; The selection unit selecting the second relationship corresponding to a current propagation environment in the second information; performing the selection process using the selected second relationship; The selection process includes: a first selection process for selecting a beam to be used for measuring the reception quality; a second selection process for selecting a beam to be used for communication with the wireless terminal; including at least one of 16. The control device of claim 15.

[0204] (Appendix 17) The first selection process includes selecting a predetermined number of beams in descending order of the number of reports. 17. The control device of claim 16.

[0205] (Appendix 18) the second selection process includes selecting a beam whose number of reports is less than a predetermined second threshold. 17. The control device of claim 16.

[0206] (Appendix 19) the update unit selects a beam for updating the database. 19. A control device according to any one of appendices 1 to 18.

[0207] (Appendix 20) the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; the updating unit transmits instruction information for instructing the radio terminal about the reception quality of the beam to be included in the measurement result. 20. The control device of claim 19.

[0208] (Appendix 21) the updating unit transmits the instruction information so that the measurement result includes the reception qualities of beams corresponding to two or more radio devices among the plurality of radio devices. 21. The control device of claim 20.

[0209] (Appendix 22) the update unit creates the database to be used in a first time period and the database to be used in a second time period; 21. The control device of claim 20.

[0210] (Appendix 23) obtaining measurements including information about the reception quality of a plurality of beams; updating a database containing information representing relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results; performing a selection process for selecting a beam using the database; A control method comprising:

[0211] (Appendix 24) a computer including a processor and a memory, obtaining measurements including information about the reception quality of a plurality of beams; updating a database containing information representing relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results; performing a selection process for selecting a beam using the database; A program that executes the following. [Industrial Applicability]

[0212] The beam can be selected appropriately. [Explanation of symbols]

[0213] 1: Wireless communication system 10-1, 10-2: Wireless terminal 20: Wireless communication device 21: Control device 22-1, 22-2: Radio equipment 331: Baseband signal processing section 510: Transmission signal processing unit 520: Received signal processing unit 530: Scheduling Department 540: Beam Management Department 610: Measurement result acquisition section 620 :DB update section 630: Beam selection unit

Claims

1. an acquisition unit that acquires measurement results including information about the reception quality of a plurality of beams; an updating unit that updates a database including information representing a relationship between the plurality of beams for each of a plurality of propagation environments based on the measurement results; a selection unit that executes a selection process for selecting a beam using the database; Equipped with In the information representing the relationship, the plurality of propagation environments are distinguished based on a similarity of the measurement results, The selection unit selecting the relationship corresponding to the current propagation environment from the information representing the relationship based on the similarity between the measurement result currently acquired and the average measurement result of each of the plurality of propagation environments; performing the selection process using the selected relationship; Control device.

2. the similarity includes a cosine similarity of a vector having the reception qualities of the plurality of beams as elements. The control device according to claim 1 .

3. the information representing the relationship includes first information representing a first relationship of the difference in reception quality between the plurality of beams; The control device according to claim 1 or 2.

4. the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; The selection unit selecting the first relationship corresponding to a current propagation environment in the first information; performing the selection process using the selected first relationship; The selection process includes: a first selection process for selecting a beam to be used for measuring the reception quality; a second selection process for selecting a beam to be used for communication with the wireless terminal; including at least one of The control device according to claim 3 .

5. the first selection process includes selecting a predetermined number of beams in order of smallest difference from a beam currently being used or to be used next; The control device according to claim 4.

6. the first selection process includes selecting the predetermined number of beams such that the predetermined number of beams includes a plurality of beams corresponding to two or more wireless devices among the plurality of wireless devices; The control device according to claim 5 .

7. When the control device communicates with the plurality of wireless terminals, the second selection process includes selecting a beam whose difference from a currently used beam is greater than a predetermined first threshold. The control device according to claim 4.

8. When the control device communicates with the same wireless terminal via the plurality of wireless devices, the second selection process includes selecting, in each of the plurality of wireless devices, a beam having the highest reception quality determined from the measurement results currently acquired. The control device according to claim 4.

9. the information representing the relationship includes second information representing a second relationship between the number of times of reporting the reception quality among the plurality of beams. The control device according to claim 1 or 2.

10. the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; The selection unit selecting the second relationship corresponding to a current propagation environment in the second information; performing the selection process using the selected second relationship; The selection process includes: a first selection process for selecting a beam to be used for measuring the reception quality; a second selection process for selecting a beam to be used for communication with the wireless terminal; including at least one of The control device according to claim 9.

11. the first selection process includes selecting a predetermined number of beams in descending order of the number of reports; The control device according to claim 10.

12. the second selection process includes selecting a beam whose number of reports is less than a predetermined second threshold. The control device according to claim 10.

13. the update unit selects a beam for updating the database. A control device according to any one of claims 1 to 12.

14. the control device is connected to a plurality of radio devices that form the plurality of beams, and is configured to communicate with a plurality of radio terminals via the plurality of radio devices; the updating unit transmits instruction information for instructing the radio terminal about the reception quality of the beam to be included in the measurement result. The control device according to claim 13.

15. the updating unit transmits the instruction information so that the measurement result includes the reception qualities of beams corresponding to two or more radio devices among the plurality of radio devices. The control device according to claim 14.

16. the update unit creates the database to be used in a first time period and the database to be used in a second time period; The control device according to claim 14.

17. obtaining measurements including information about the reception quality of a plurality of beams; updating a database containing information representing relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results; performing a selection process for selecting a beam using the database; Including, In the information representing the relationship, the plurality of propagation environments are distinguished based on a similarity of the measurement results, Executing the selection process includes: selecting the relationship corresponding to the current propagation environment from the information representing the relationship based on the degree of similarity between the measurement result currently acquired and the average measurement result of each of the plurality of propagation environments; performing the selection process using the selected relationship; and Including, Control method.

18. a computer including a processor and a memory, obtaining measurements including information about the reception quality of a plurality of beams; updating a database containing information representing relationships between the plurality of beams for each of a plurality of propagation environments based on the measurement results; performing a selection process for selecting a beam using the database; A program for executing In the information representing the relationship, the plurality of propagation environments are distinguished based on a similarity of the measurement results, Executing the selection process includes: selecting the relationship corresponding to the current propagation environment from the information representing the relationship based on the degree of similarity between the measurement result currently acquired and the average measurement result of each of the plurality of propagation environments; performing the selection process using the selected relationship; and Including, program.

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