Terminal, base station, and program for performing beamforming using multiple antennas

Abstract

A base station has a plurality of antennas corresponding to beamforming capable of transmitting downlink beams in a plurality of orientations. The terminal is provided with: a plurality of antennas corresponding to beamforming and capable of transmitting uplink beams to a plurality of orientations; the communication quality measuring unit is used for measuring the communication quality of a plurality of downlink beams from each base station aiming at each uplink beam in different directions in the terminal; a downlink optimal beam selection unit that selects a downlink optimal beam having a communication quality equal to or greater than a predetermined condition from among a plurality of downlink beams in each base station, for each uplink beam in different orientations; and an uplink optimal beam selection unit that selects, from among the plurality of uplink beams in the terminal, an uplink optimal beam in which the sum of the communication quality of the downlink optimal beams in all the base stations is equal to or greater than a predetermined condition.

Description

Technical Field

[0001] The present invention relates to a beamforming technology using multiple antennas between a terminal and a base station. Background Art

[0002] The higher the frequency band of radio waves used between a terminal and a base station, the farther the radio waves cannot reach. Therefore, there is a technology called "beamforming" that reduces the wide-angle range of radio waves and concentrates the power, thereby making the radio waves reach a longer distance.

[0003] "Beamforming" refers to a technology that uses a narrowed wide-angle beam to perform concentrated transmission in order to compensate for transmission loss. The synchronization signal for multiple beamforming is set as an SS / PBCH (Synchronization Signal / Physical Broadcast Channel) block, and a half frame containing the block is generated at each constant cycle. In addition, there are types of beamforming such as full digital, analog, and hybrid.

[0004] The "multi-antenna" sequentially transmits beamformed wireless signals through beam scanning.

[0005] In addition, multi-antennas supporting beamforming are also called massive MIMO, and are composed of tens to hundreds of antenna elements.

[0006] According to the existing cellular system, antenna equipment and accommodation areas are managed for each base station. Therefore, interference may occur between other adjacent base stations depending on the location of the terminal or the time period, thereby reducing the communication quality.

[0007] In response to this, there is also "AP Clustering Technology" in which a terminal communicates by connecting to multiple base stations. CFmMIMO (Cell-Free Massive Multi Input Multi Output) is applied to this technology to achieve high quality of communication between the terminal and the base station and low power consumption of the base station (for example, refer to Non-Patent Document 1).

[0008] According to CFmMIMO, each base station is equipped with multiple antennas in a dispersed manner and connected to suppress the influence of interference between the terminal and multiple base stations. In addition, the base station sends a reference signal to the terminal while scanning the downlink beam in multiple directions. The terminal receives the reference signal and notifies the base station of the identifier of the best downlink beam with the maximum received signal power.

[0009] Prior art literature

[0010] Non-patent literature

[0011] Non-Patent Literature 1: "KDDI Research Institute, Demonstration Experiment of MIMO Technology Achieving Improved Communication Quality and Energy Saving", [online], [retrieved on September 5, 2019], Internet <URL: https: / / k-tai.watch.impress.co.jp / docs / news / 1384661.html> Summary of the invention

[0012] Problems to be solved by the invention

[0013] In recent years, there are also terminals that can be equipped with multiple antennas that support beamforming and transmit multiple uplink beams.

[0014] In the case of a cellular system, in order to connect to a base station, a terminal can select an uplink optimal beam that maximizes the received signal power.

[0015] However, for example, in the following example, it is difficult to decide whether to combine multiple uplink beams of the terminal with multiple downlink beams of the base station.

[0016] (Example 1)

[0017] When a terminal is connected to multiple base stations at the same time, the combination of the terminal's multiple uplink beams and the multiple downlink beams of the multiple base stations is

[0018] (Example 2)

[0019] When a base station communicates with multiple terminals at the same time, the combination of multiple downlink beams of the base station and multiple uplink beams of each of the multiple terminals

[0020] That is, in order to assume multiple connections in which one or more terminals communicate simultaneously with one or more base stations, even if uplink beams and downlink beams are determined with priority given to one path, communication quality (eg, received signal power) may deteriorate for other paths.

[0021] Means used to solve problems

[0022] In the case of simultaneous multiple connections between a terminal and a base station, the present invention can provide a terminal, a base station, and a program for selecting an optimal combination of an uplink beam and a downlink beam in beamforming.

[0023] According to the present invention, a terminal communicates with multiple base stations simultaneously, the multiple base stations having multiple antennas corresponding to beamforming capable of sending downlink beams to multiple directions, wherein:

[0024] The terminal has:

[0025] Multiple antennas for beamforming, which can send uplink beams in multiple directions;

[0026] A communication quality measurement unit, which measures the communication quality of multiple downlink beams from each base station for each uplink beam in a different orientation in the terminal;

[0027] a downlink best beam selection unit, which selects, for each uplink beam in a different azimuth, a downlink best beam whose communication quality exceeds a predetermined condition from among a plurality of downlink beams in each base station; and

[0028] The uplink best beam selection unit selects, from among the plurality of uplink beams in the terminal, the uplink best beam for which the sum of the communication qualities of the downlink best beams in all base stations is equal to or greater than a predetermined condition.

[0029] According to other embodiments of the terminal of the present invention,

[0030] The terminal further includes a beam table notification unit that notifies the base station control device via the base station of a beam table that associates an identifier of the uplink beam of the terminal with identifiers of optimal downlink beams of each base station.

[0031] According to other embodiments of the terminal of the present invention,

[0032] The downlink optimal beam selection unit selects one or more downlink optimal beams whose communication quality meets or exceeds a predetermined condition.

[0033] The beam table notification unit associates identifiers of one or more downlink optimal beams of each base station in the beam table.

[0034] According to other embodiments of the terminal of the present invention,

[0035] The beam table notification unit further associates the communication quality of the optimal downlink beam of each base station in the beam table with respect to the identifier of each uplink beam of the terminal.

[0036] According to other embodiments of the terminal of the present invention,

[0037] The beam table notification unit further notifies the terminal of a combination of identifiers of uplink beams that can be transmitted simultaneously among the plurality of uplink beams.

[0038] According to the present invention, a base station communicates with a plurality of terminals simultaneously, the plurality of terminals having a plurality of antennas corresponding to beamforming capable of sending uplink beams to a plurality of directions, wherein:

[0039] The base station has:

[0040] Multiple antennas for beamforming, which can send downlink beams in multiple directions;

[0041] A communication quality measurement unit, which measures the communication quality of multiple uplink beams from each terminal for each downlink beam in different directions in the base station;

[0042] an uplink best beam selection unit, which selects, for each downlink beam in different directions, an uplink best beam having a communication quality exceeding a predetermined condition for each terminal from among a plurality of uplink beams; and

[0043] The downlink best beam selection unit selects, from among a plurality of downlink beams in the base station, a downlink best beam whose total sum of communication qualities of uplink best beams in all terminals is equal to or greater than a predetermined condition.

[0044] According to other implementations of the base station of the present invention,

[0045] The base station further includes a beam table notification unit that notifies the base station control device of a beam table that associates an identifier of a downlink beam of the base station with an identifier of an uplink optimal beam of each terminal.

[0046] According to other implementations of the base station of the present invention,

[0047] The uplink optimal beam selection unit selects one or more uplink optimal beams whose communication quality meets or exceeds a predetermined condition.

[0048] The beam table notification unit associates the identifiers of one or more uplink optimal beams for each terminal in the beam table.

[0049] According to other implementations of the base station of the present invention,

[0050] The beam table notification unit further associates the communication quality of the uplink optimal beam of each terminal in the beam table with respect to the identifier of each downlink beam of the base station.

[0051] According to other implementations of the base station of the present invention,

[0052] The beam table notification unit further notifies the base station of a combination of identifiers of downlink beams that can be transmitted simultaneously among the plurality of downlink beams.

[0053] According to the present invention, a program is provided for causing a computer mounted on a terminal to function, the terminal communicating simultaneously with a plurality of base stations having multiple antennas corresponding to beamforming capable of transmitting downlink beams in a plurality of directions, wherein:

[0054] The terminal has multiple antennas corresponding to beamforming capable of sending uplink beams in multiple directions.

[0055] The program causes the computer to function as the following means:

[0056] A communication quality measurement unit, which measures the communication quality of multiple downlink beams from each base station for each uplink beam in a different orientation in the terminal;

[0057] a downlink best beam selection unit, which selects, for each uplink beam in a different azimuth, a downlink best beam whose communication quality exceeds a predetermined condition from among a plurality of downlink beams in each base station; and

[0058] The uplink best beam selection unit selects, from among the plurality of uplink beams in the terminal, the uplink best beam for which the sum of the communication qualities of the downlink best beams in all base stations is equal to or greater than a predetermined condition.

[0059] According to the present invention, a program is provided for causing a computer mounted on a base station to function, the base station communicating simultaneously with a plurality of terminals having a plurality of antennas corresponding to beamforming capable of transmitting uplink beams in a plurality of directions, wherein:

[0060] The base station has multiple antennas corresponding to beamforming capable of sending downlink beams to multiple directions.

[0061] The program causes the computer to function as the following means:

[0062] A communication quality measurement unit, which measures the communication quality of multiple uplink beams from each terminal for each downlink beam in different directions in the base station;

[0063] an uplink best beam selection unit, which selects, for each downlink beam in different directions, an uplink best beam having a communication quality exceeding a predetermined condition for each terminal from among a plurality of uplink beams; and

[0064] The downlink best beam selection unit selects, from among a plurality of downlink beams in the base station, a downlink best beam whose total sum of communication qualities of uplink best beams in all terminals is equal to or greater than a predetermined condition.

[0065] Effects of the Invention

[0066] According to the terminal, the base station, and the program of the present invention, when multiple connections are simultaneously established between the terminal and the base station, it is possible to select an optimal combination of uplink beams and downlink beams in beamforming.

[0067] Other features and advantages of the present invention will become clear from the following description with reference to the accompanying drawings. In addition, in the accompanying drawings, the same or similar structures are marked with the same reference numerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0069] Figure 1 It is a diagram showing the configuration of beamforming in the first embodiment.

[0070] Figure 2 It is a functional configuration diagram of a terminal in the first embodiment.

[0071] Figure 3 This is the communication quality table in the first embodiment.

[0072] Figure 4 This is the beam table in the first embodiment.

[0073] Figure 5 This is a timing chart in the first embodiment.

[0074] Figure 6 This is a configuration diagram showing a combination of beams that can be used simultaneously by a terminal in the first embodiment.

[0075] Figure 7 is based on Figure 6 beam table.

[0076] Figure 8 It is a diagram showing the configuration of beamforming in the second embodiment.

[0077] Fig. 9 It is a functional configuration diagram of a base station in the second embodiment.

[0078] Fig.10 This is the communication quality table in the second embodiment.

[0079] Fig.11 This is the beam table in the second embodiment. DETAILED DESCRIPTION

[0080] The following detailed description of the embodiments is made with reference to the accompanying drawings. In addition, the following embodiments do not limit the invention involved in the technical solution. In addition, not all feature combinations described in the embodiments are necessary for the invention. Two or more features of the multiple features described in the embodiments may also be combined arbitrarily. In addition, the same or similar configurations are marked with the same reference numerals, and repeated descriptions are omitted.

[0081] The following examples are described above.

[0082] <Example 1>

[0083] When a terminal is connected to multiple base stations at the same time, the combination of the terminal's multiple uplink beams and the multiple downlink beams of the multiple base stations is

[0084] <Example 2>

[0085] When a base station communicates with multiple terminals at the same time, the combination of multiple downlink beams of the base station and multiple uplink beams of each of the multiple terminals

[0086] <Example 1>

[0087] Figure 1 It is a diagram showing the configuration of beamforming in the first embodiment of the present invention.

[0088] according to Figure 1 , which means that when a terminal is connected to multiple base stations at the same time, the terminal's multiple uplink beams are combined with the multiple downlink beams of multiple base stations.

[0089] according to Figure 1 The system comprises a terminal 1, three base stations 21 to 23 and a base station control device 3.

[0090] The terminal 1 has a multi-antenna compatible with beamforming capable of transmitting uplink beams in multiple directions, and simultaneously communicates with multiple base stations 2. Here, the transmission beam from the terminal 1 is referred to as an "uplink beam".

[0091] according to Figure 1 , the multiple antennas of terminal 1 can respectively transmit uplink beams #1 to #4 in four directions. The multiple antennas scan the reference signal of the uplink beam while transmitting the reference signal of the uplink beam to different directions. The reference signal includes the identifier # of the uplink beam.

[0092] Base stations 21 to 23 each have a multi-antenna compatible with beamforming capable of transmitting downlink beams in multiple directions, and simultaneously communicate with terminal 1. Here, a transmission beam from each base station 21 to 23 is referred to as a "downlink beam".

[0093] according to Figure 1 , the multiple antennas of base stations 21 to 23 can respectively transmit downlink beams #1 to #8 in eight directions. The multiple antennas scan the reference signal of the downlink beam while transmitting the reference signal of the downlink beam to different directions. The reference signal includes the identifier # of the downlink beam.

[0094] The base station control device 3 determines the optimal downlink beam for communicating with the terminal 1 for each of the base stations 21 to 23, and controls the base station. The base station control device 3 also manages the uplink beam of the terminal 1.

[0095] Figure 2 It is a functional configuration diagram of a terminal in the first embodiment of the present invention.

[0096] according to Figure 2The terminal 1 includes a communication quality measuring unit 101, a downlink optimal beam selecting unit 102, an uplink optimal beam selecting unit 103, an uplink beam controlling unit 104, a beam table notifying unit 105, and an uplink beam notifying unit 106 together with a multi-antenna 100. These functional structural units other than the multi-antenna are implemented by executing a program that enables a computer mounted on the terminal to function. In addition, the processing flow of these functional structural units can also be understood as a beam selection method in a terminal having multiple antennas.

[0097] [Communication Quality Measurement Unit 101]

[0098] The communication quality measurement unit 101 measures the communication quality of a plurality of downlink beams from each base station 2 for each uplink beam in a different azimuth in the terminal 1. The communication quality may be, for example, received signal power.

[0099] Figure 3 This is the communication quality table in the first embodiment of the present invention.

[0100] according to Figure 3 , for each uplink beam #1 to uplink beam #4 of the terminal 1, the received signal power (communication quality) of the downlink beam #1 to downlink beam #8 of each base station 21 to base station 23 is shown.

[0101] [Downlink optimal beam selection unit 102]

[0102] The best downlink beam selection unit 102 selects a “best downlink beam” having a communication quality exceeding a predetermined condition from among a plurality of downlink beams in each base station for each uplink beam in different azimuths in the terminal 1 .

[0103] As the "predetermined condition" for selecting the optimal downlink beam, for example, the downlink beam with the highest communication quality may be selected.

[0104] according to Figure 3 For example, for uplink beam #1 of terminal 1, among downlink beams #1 to #8 in base station 21, downlink beam #1 with the highest communication quality is selected as the best downlink beam. Similarly, next, for uplink beam #1 of terminal 1, among downlink beams #1 to #8 in base station 22, downlink beam #4 with the highest communication quality is selected as the best downlink beam.

[0105] Furthermore, for uplink beam #2 of terminal 1, downlink beam #3 having the highest communication quality is selected as the best downlink beam from among downlink beams #1 to #8 in base station 21.

[0106] [Uplink optimal beam selection unit 103]

[0107] The uplink best beam selection unit 103 selects, from among the plurality of uplink beams in the terminal 1, an “uplink best beam” for which the sum of the communication qualities of the downlink best beams in all the base stations 2 is equal to or greater than a predetermined condition.

[0108] As a "predetermined condition" for selecting the best uplink beam, for example, a downlink beam with the highest communication quality may be selected.

[0109] according to Figure 3 For example, among the multiple uplink beams #1 to #4 in the terminal 1, the sum of the communication qualities of the best downlink beams in all the base stations 2 is calculated.

[0110] Based on the uplink beam #1 of terminal 1, the sum of the communication qualities of downlink beam #1 of base station 21, downlink beam #4 of base station 22, and downlink beam #7 of base station 23, which are the best downlink beams, is calculated. Similarly, based on the uplink beam #2 of terminal 1, the sum of the communication qualities of downlink beam #3 of base station 21, downlink beam #4 of base station 22, and downlink beam #4 of base station 23, which are the best downlink beams, is calculated.

[0111] Finally, the uplink beam #2 of the terminal 1 having the highest sum of the communication qualities of the best downlink beams in all the base stations 2 is selected as the “best uplink beam”.

[0112] [Uplink beam control unit 104]

[0113] The uplink beam control unit 104 controls the multi-antenna 100 so as to communicate with a plurality of base stations 2 simultaneously using the “uplink optimal beam”.

[0114] [Beam table notification unit 105]

[0115] The beam table notification unit 105 creates a "beam table" in which identifiers of a plurality of uplink beams of the terminal 1 are associated with identifiers of optimal downlink beams of each base station.

[0116] The beam table can be used for beam management, for example. The following control is defined as a beam table based on the specification of beam management.

[0117] Beam determination: selection of transmit beam / receive beam

[0118] Beam measurement: The communication quality of the received signal of the beam

[0119] Beam reporting: reporting of information related to the beam

[0120] Beam sweeping: scanning of a spatial area (e.g. 360 degrees)

[0121] Figure 4 This is the beam table in the first embodiment of the present invention.

[0122] according to Figure 4 , the plurality of uplink beams #1 to #4 in the terminal 1 are arranged in a vertical column. Then, for each uplink beam, an identifier of the best downlink beam of each base station 21 to base station 23 is associated.

[0123] according to Figure 4 , for example, create a beam table like the following.

[0124] With respect to the uplink beam #1 of the terminal 1, among the best downlink beams received from the base station 21, an identifier of the best downlink beam #1 having the highest received signal strength is associated.

[0125] The uplink beam #2 of the terminal 1 is associated with the identifier of the downlink best beam #3 having the highest received signal strength among the downlink best beams received from the base station 21 .

[0126] The uplink beam #3 of the terminal 1 is associated with the identifier of the downlink best beam #4 having the highest received signal strength among the downlink best beams received from the base station 21 .

[0127] The uplink beam #4 of the terminal 1 is associated with the identifier of the downlink best beam #2 having the highest received signal strength among the downlink best beams received from the base station 21 .

[0128] …

[0129] In this way, from the perspective of the terminal 1, the other base stations 21 and 23 can also be associated in the same manner.

[0130] In addition, the beam table notification unit 105 may further associate the “communication quality” of the best downlink beam from each base station 2 with respect to the identifier # 1 to the identifier # 4 of each uplink beam of the terminal 1 in the beam table.

[0131] Then, the beam table notification unit 105 notifies the base station control device 3 of the beam table via the base station 2. The base station control device 3 can know which downlink optimal beam of each base station 21 to base station 23 is selected based on the uplink beam selected by the terminal 1 to improve communication quality.

[0132] [Uplink beam notification unit 106]

[0133] The uplink beam notification unit 106 notifies each base station 2 of the identifier of the uplink beam of the terminal 1 and the identifier of the optimal downlink beam of the base station corresponding to the identifier of the uplink beam.

[0134] Figure 5This is a timing chart in the first embodiment of the present invention.

[0135] The uplink beam notification unit 106 notifies each base station 2 of the identifier of the uplink optimal beam selected for the terminal 1 .

[0136] Figure 6 This is a configuration diagram showing a combination of beams that can be used simultaneously by a terminal in the first embodiment of the present invention.

[0137] according to Figure 6 , assuming that the terminal 1 has multiple multi-antennas 100. The number of uplink beams that the terminal 1 can send simultaneously is also multiple.

[0138] In this case, the beam table notification unit 105 further notifies the terminal 1 of a combination of identifiers of uplink beams that can be transmitted simultaneously among a plurality of uplink beams.

[0139] Number of beams that can be used simultaneously: 2

[0140] Combinations that can be used simultaneously (uplink beam #1, uplink beam #3)

[0141] (Uplink beam #1, Uplink beam #4)

[0142] (Uplink beam #2, Uplink beam #3)

[0143] (Uplink beam #2, Uplink beam #4)

[0144] Figure 7 is based on Figure 6 beam table.

[0145] The aforementioned optimal downlink beam selection unit 102 may select one or more optimal downlink beams whose communication quality satisfies a predetermined condition or higher.

[0146] For example, when the communication quality is the received signal power, it is possible to set a predetermined condition such as the following and select a plurality of downlink optimal beams.

[0147] (Predetermined condition 1) A maximum of xx downlink beams in descending order of received signal power

[0148] (Predetermined condition 2) The received signal power is above yydBm in the downlink beam

[0149] (Predetermined condition 3) Maximum xx downlink beams with received signal power above yydBm

[0150] thus, Figure 7 The beam table and Figure 4 By comparing the beam table, for each uplink beam of terminal 1, there is more than one associated optimal downlink beam.

[0151] In addition, Figure 7 The beam table also contains Figure 6 A combination of beams that can be used simultaneously by terminal 1 in.

[0152] Thus, the base station control device 3 that has received the beam table can know that the optimal downlink beam with high communication quality to the base station 2 is associated with each beam that can be used simultaneously by the terminal 1 .

[0153] <Example 2>

[0154] Figure 8 It is a diagram showing the configuration of beamforming in the second embodiment of the present invention.

[0155] according to Figure 8 ,and Figure 1 In comparison, when one base station 2 communicates with a plurality of terminals simultaneously, a combination of a plurality of downlink beams of the base station and a plurality of uplink beams of each of the plurality of terminals is shown.

[0156] The terminal 1 has multiple antennas corresponding to beamforming that can transmit uplink beams in multiple directions. The functions of the terminal 1, the base station 2, and the base station control device 3 are similar to Figure 1 Exactly the same.

[0157] Fig. 9 It is a functional configuration diagram of a base station in the second embodiment of the present invention.

[0158] according to Fig. 9 The base station 2 includes a communication quality measurement unit 201, an uplink optimal beam selection unit 202, a downlink optimal beam selection unit 203, a downlink beam control unit 204, a beam table notification unit 205, and a downlink beam notification unit 206 together with the multi-antenna 200. These functional components other than the multi-antenna are implemented by executing a program that enables a computer mounted on the base station to function. In addition, the process flow of these functional components can also be understood as a beam selection method in a base station with multiple antennas.

[0159] Compare Fig. 9 With the aforementioned Figure 2 , the following functions are relatively the same.

[0160] < Figure 2 Terminal side> <-> < Fig. 9 Base station side>

[0161] Communication quality measurement unit 101 Communication quality measurement unit 201

[0162] Downlink optimal beam selection unit 102 Uplink optimal beam selection unit 202

[0163] Uplink best beam selection unit 103 Downlink best beam selection unit 203

[0164] Uplink beam control unit 104 Downlink beam control unit 204

[0165] Beam table notification unit 105 Beam table notification unit 205

[0166] Uplink beam notification unit 106 Downlink beam notification unit 206

[0167] [Multiple Antennas 200]

[0168] The multi-antenna 200 is a beamforming-compatible multi-antenna capable of transmitting downlink beams in multiple directions.

[0169] [Communication Quality Measurement Unit 201]

[0170] The communication quality measurement unit 201 measures the communication quality of a plurality of uplink beams from each of the terminals 11 to 13 for each downlink beam in a different azimuth in the base station 2 .

[0171] Fig.10 This is a communication quality table in the second embodiment of the present invention.

[0172] according to Fig.10 For each downlink beam #1 to downlink beam #8 in a different azimuth in the base station 2, the received signal power (communication quality) of multiple uplink beams #1 to uplink beams #4 from the terminals 11 to 13 is associated.

[0173] [Uplink optimal beam selection unit 202]

[0174] The uplink optimal beam selection unit 202 selects the uplink optimal beam having a communication quality that satisfies a predetermined condition or higher from among a plurality of uplink beams for each of the terminals 11 to 13 for each of the downlink beams in different azimuths.

[0175] according to Fig.10 For example, for downlink beam #1 of base station 2, uplink beam #1 with the highest communication quality is selected as the best uplink beam among uplink beams #1 to #4 in terminal 11. Similarly, next, for downlink beam #1 of base station 2, uplink beam #4 with the highest communication quality is selected as the best uplink beam among downlink beams #1 to #4 in terminal 12.

[0176] Furthermore, for downlink beam #2 of base station 2, uplink beam #3 having the highest communication quality is selected as the best uplink beam among uplink beams #1 to #4 in terminal 11.

[0177] Furthermore, the uplink optimal beam selection unit 202 may select one or more uplink optimal beams whose communication quality satisfies a predetermined condition or higher.

[0178] [Downlink optimal beam selection unit 203]

[0179] The downlink optimal beam selection unit 203 selects the downlink optimal beam whose total communication quality of the uplink optimal beams in all the terminals 1 is equal to or higher than a predetermined condition, from among the plurality of downlink beams in the base station 2 .

[0180] according to Fig.10 For example, among the multiple uplink beams #1 to #8 in the base station 2, the sum of the communication qualities of the best downlink beams in all the terminals 1 is calculated.

[0181] Based on downlink beam #1 of base station 2, the sum of the communication qualities of uplink beam #1 of terminal 11, uplink beam #4 of terminal 12, and uplink beam #3 of terminal 13, which are the best uplink beams, is calculated. Similarly, based on downlink beam #2 of base station 2, the sum of the communication qualities of uplink beam #3 of terminal 11, uplink beam #4 of terminal 12, and uplink beam #4 of terminal 13, which are the best uplink beams, is calculated.

[0182] Finally, the downlink beam #2 of the base station 2 having the highest total communication quality of the downlink best beams among all the terminals 11 to 13 is selected as the “downlink best beam”.

[0183] The downlink beam control unit 204 controls the multi-antenna 200 using the selected optimal downlink beam.

[0184] [Beam table notification unit 205]

[0185] The beam table notification unit 205 notifies the base station control device 3 of a beam table in which the identifier of the downlink beam of the base station and the identifier of the best uplink beam of each terminal are associated with each other.

[0186] Fig.11 This is a beam table in the second embodiment of the present invention.

[0187] according to Fig.11 , for example, create a beam table like the following.

[0188] With respect to the downlink beam #1 of the base station 2, among the best uplink beams received from the terminal 11, an identifier of the best uplink beam #1 having the highest received signal strength is associated.

[0189] The downlink beam #2 of the base station 2 is associated with the identifier of the uplink best beam #3 having the highest received signal strength among the uplink best beams received from the terminal 11 .

[0190] …

[0191] The downlink beam #8 of the base station 2 is associated with the identifier of the uplink best beam #2 having the highest received signal strength among the uplink best beams received from the terminal 11.

[0192] …

[0193] In addition, the beam table notification unit 205 may associate the identifiers of one or more uplink optimal beams for each terminal with each other in the beam table.

[0194] Furthermore, the beam table notification unit 205 may further associate the communication quality of the uplink best beam of each terminal in the beam table with respect to the identifier of each downlink beam of the base station.

[0195] Furthermore, the beam table notification unit 205 may further notify a combination of identifiers of downlink beams that can be simultaneously transmitted among a plurality of downlink beams in the base station.

[0196] [Downlink beam notification unit 206]

[0197] The downlink beam notification unit 206 notifies each terminal 1 of the identifier of the downlink beam of the base station 2 and the identifier of the best uplink beam of the terminal corresponding to the identifier of the downlink beam.

[0198] As described above in detail, according to the terminal, the base station, and the program of the present invention, when multiple connections are simultaneously established between the terminal and the base station, it is possible to select an optimal combination of uplink beams and downlink beams in beamforming.

[0199] In addition, since, for example, "wireless resources between terminals and base stations can be effectively utilized", it is possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs) of "building resilient infrastructure and promoting inclusive and sustainable industry".

[0200] The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

[0201] This application claims priority based on Japanese patent application No. 2022-156966 filed on September 29, 2022, the entire contents of which are incorporated herein by reference.

Claims

1. A terminal that communicates with multiple base stations simultaneously, the multiple base stations having multiple antennas corresponding to beamforming capable of sending downlink beams to multiple directions, wherein: The terminal has: Multiple antennas for beamforming, which can send uplink beams in multiple directions; A communication quality measurement unit, which measures the communication quality of multiple downlink beams from each base station for each uplink beam in a different orientation in the terminal; A downlink best beam selection unit, which selects a downlink best beam whose communication quality exceeds a predetermined condition from among a plurality of downlink beams in each base station for each uplink beam in a different azimuth; as well as The uplink best beam selection unit selects, from among the plurality of uplink beams in the terminal, the uplink best beam for which the sum of the communication qualities of the downlink best beams in all base stations is equal to or greater than a predetermined condition.

2. The terminal according to claim 1, wherein: The terminal further includes a beam table notification unit that notifies the base station control device via the base station of a beam table that associates an identifier of the uplink beam of the terminal with identifiers of optimal downlink beams of each base station.

3. The terminal according to claim 2, wherein: The downlink optimal beam selection unit selects one or more downlink optimal beams whose communication quality meets or exceeds a predetermined condition. The beam table notification unit associates identifiers of one or more downlink optimal beams of each base station in the beam table.

4. The terminal according to claim 2 or 3, wherein: The beam table notification unit further associates the communication quality of the optimal downlink beam of each base station in the beam table with the identifier of each uplink beam of the terminal.

5. The terminal according to claim 2 or 3, wherein: The beam table notification unit further notifies the terminal of a combination of identifiers of uplink beams that can be transmitted simultaneously among the plurality of uplink beams.

6. A base station that communicates with a plurality of terminals simultaneously, the plurality of terminals having a plurality of antennas corresponding to beamforming capable of sending uplink beams in a plurality of directions, wherein: The base station has: Multiple antennas for beamforming, which can send downlink beams in multiple directions; A communication quality measurement unit, which measures the communication quality of multiple uplink beams from each terminal for each downlink beam in different directions in the base station; An uplink best beam selection unit, which selects, for each downlink beam in different directions, an uplink best beam whose communication quality exceeds a predetermined condition from among a plurality of uplink beams for each terminal; as well as The downlink best beam selection unit selects, from among a plurality of downlink beams in the base station, a downlink best beam whose total sum of communication qualities of uplink best beams in all terminals is equal to or greater than a predetermined condition.

7. The base station according to claim 6, wherein: The base station further includes a beam table notification unit that notifies the base station control device of a beam table that associates an identifier of a downlink beam of the base station with an identifier of an uplink optimal beam of each terminal.

8. The base station according to claim 7, wherein: The uplink optimal beam selection unit selects one or more uplink optimal beams whose communication quality meets or exceeds a predetermined condition. The beam table notification unit associates the identifiers of one or more uplink optimal beams for each terminal in the beam table.

9. The base station according to claim 7 or 8, wherein: The beam table notification unit further associates the communication quality of the uplink optimal beam of each terminal in the beam table with respect to the identifier of each downlink beam of the base station.

10. The base station according to claim 7 or 8, wherein: The beam table notification unit further notifies the base station of a combination of identifiers of downlink beams that can be transmitted simultaneously among the plurality of downlink beams.

11. A program for causing a computer mounted on a terminal to function, the terminal communicating simultaneously with a plurality of base stations having multiple antennas corresponding to beamforming capable of transmitting downlink beams in a plurality of directions, wherein: The terminal has multiple antennas corresponding to beamforming capable of sending uplink beams in multiple directions. The program causes the computer to function as the following means: A communication quality measurement unit, which measures the communication quality of multiple downlink beams from each base station for each uplink beam in a different orientation in the terminal; A downlink best beam selection unit, which selects a downlink best beam whose communication quality exceeds a predetermined condition from among a plurality of downlink beams in each base station for each uplink beam in a different azimuth; as well as The uplink best beam selection unit selects, from among the plurality of uplink beams in the terminal, the uplink best beam for which the sum of the communication qualities of the downlink best beams in all the base stations is equal to or greater than a predetermined condition.

12. A program for causing a computer mounted on a base station to function, the base station communicating simultaneously with a plurality of terminals having a plurality of antennas corresponding to beamforming capable of transmitting uplink beams in a plurality of directions, wherein: The base station has multiple antennas corresponding to beamforming capable of sending downlink beams to multiple directions. The program causes the computer to function as the following means: A communication quality measurement unit, which measures the communication quality of multiple uplink beams from each terminal for each downlink beam in different directions in the base station; An uplink best beam selection unit, which selects, for each downlink beam in different directions, an uplink best beam whose communication quality exceeds a predetermined condition from among a plurality of uplink beams for each terminal; as well as The downlink best beam selection unit selects a downlink best beam whose total communication quality of the uplink best beams in all the terminals is equal to or higher than a predetermined condition, from among the plurality of downlink beams in the base station.

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