Base station, terminal device, and communication system

Abstract

This base station comprises: a group control unit that forms one or more groups from a plurality of antennas on the basis of an index value of each of the antennas; a communication control unit that forms cells from the one or more groups by associating the groups with the communication resources of the respective cells; and a communication unit that uses antennas forming a group which is associated with the communication resource of a cell to conduct communication with a terminal device present in the cell. The index value of each of the antennas may be an index value of the relationship between an antenna and another antenna or a terminal device. The terminal device may comprise: an estimation unit that estimates the index value of each of the antennas on the basis of a radio signal which is transmitted from each of the plurality of antennas disposed in a distributed manner, information which indicates the result of electromagnetic simulation, or sensing information with respect to the antennas; and a terminal transmission unit that transmits a radio signal which contains the index value of each of the antennas.

Description

Base station, terminal device and communication system

[0001] The present invention relates to a base station, a terminal device, and a communication system.

[0002] The fifth-generation mobile communication system (5G) uses high-frequency millimeter-wave bands. Future wireless systems will be required to provide even faster and larger-capacity communications. Therefore, the sixth-generation mobile communication system (6G) is expected to use higher frequency bands to ensure wider bandwidth.

[0003] However, in high frequency bands, radio waves have large propagation losses and tend to travel in a straight line. Therefore, distributed antenna systems that can improve communication connectivity even in high frequency bands are being studied (see Non-Patent Document 1).

[0004] FIG. 7 is a diagram showing an example of the configuration of a cellular system. A wireless digital processing unit (BBU: Base Band Unit) performs digital processing for wireless communication in layers above the physical layer. An extension unit (RRH: Remote Radio Head) performs radio frequency (RF) processing. The extension unit may also perform part of the processing in the physical layer. An antenna 11 is a transmission and reception point (TRP: Transmission and Reception Point). The antenna 11 may extend further from the extension unit or may be integrated with the extension unit.

[0005] 8 is a diagram showing a first example of the configuration of a distributed antenna system. In FIG. 8, multiple antennas 12 (distributed antennas) extending further from an extension unit cover a common cell. For example, antennas 12-1-1 and 12-1-2 extending further from an extension unit (RRH) "cell #1" cover cell "#1." Note that a terminal device "UE" serving as a user terminal may exist in the cell.

[0006] In a distributed antenna system, the communication area of ​​each cell is expanded by the antennas 12 extending further from the extension parts. This ensures line of sight of radio waves and shortens communication distances. Furthermore, communication capacity is increased by the multiple antennas 12 cooperating to perform MIMO (Multiple-Input Multiple-Output) communication.

[0007] 9 is a diagram showing an example of the configuration of a single frequency network (SFN). A plurality of sets of extensions and antennas 12 may extend a single cell (cell #1 in FIG. 9).

[0008] Fig. 10 is a diagram showing a second example of the configuration of a distributed antenna system. The communication device is a central station. The communication device also has communication resources for each cell. The communication resources (cell resources) are, for example, a data communication card and a communication infrastructure. In Fig. 10, multiple antennas 12 extend from each communication resource. Each antenna 12 transmits and receives radio signals to and from a terminal device (UE) within the cell.

[0009] Non-Patent Document 2 proposes consolidating communication functions in a communication device using analog RoF (Radio over Fiber) technology. A switching unit (switch) connects communication resources and antennas 12 for each cell. The communication device dynamically changes the communication area of ​​each cell in units of antennas 12 based on load indicators (traffic volume and number of connected users of each cell). Using this cell clustering method, the communication device forms cells.

[0010] “Docomo 6G White Paper 5.0”, [online], November 2022, NTT Docomo, Inc., [Retrieved May 17, 2024], Internet <URL: https: / / www.docomo.ne.jp / binary / pdf / corporate / technology / whitepaper_6g / DOCOMO_6G_White_PaperJP_20221116.pdf> Kota Ito, Mizuki Suga, Yushi Shirato, Naoki Kita, and Takeshi Onizawa, “Efficiently Accommodating High-frequency-band Wireless Systems by Using Analog Radio-over-fiber,” Vol.18, No.5, pp.19-23, [online], May 2020, [Retrieved May 17, 2020], NTT Technical Review, Internet<URL: https: / / doi.org / 10.53829 / ntr202005fa3>

[0011] 7, 8, and 9, the communication load may be concentrated on a specific remote radio head (RRH) and the communication resources of a specific cell due to the volume of communication traffic and the uneven distribution of terminal devices (UE). Also, in cells and time periods where the volume of communication traffic and the number of terminal devices wirelessly connected to the remote radio head are low, there is a high possibility that surplus communication resources will occur, which may result in waste in terms of power consumption, etc.

[0012] In contrast, in Figure 10, it is possible to distribute the load of communication resources between cells. However, if specific antennas 12 belong to different cells, radio wave interference between those antennas 12 may increase, resulting in a deterioration in the quality of wireless communication. In addition, radio wave shielding or the like may reduce communication connectivity, resulting in a deterioration in the quality of wireless communication. Thus, there is a problem in that it is not possible to distribute the load between cells while suppressing deterioration in the quality of wireless communication.

[0013] In view of the above circumstances, an object of the present invention is to provide a base station, a terminal device, and a communication system that are capable of distributing the load between cells while suppressing deterioration in the quality of wireless communication.

[0014] One aspect of the present invention is a base station comprising: a group control unit that forms one or more groups from a plurality of antennas based on an index value for each antenna; a communication control unit that forms a cell from the one or more groups by associating the group with communication resources for each cell; and a communication unit that performs communication with a terminal device present in the cell using the antennas that form the group associated with the communication resources of the cell.

[0015] One aspect of the present invention is a terminal device comprising an estimation unit that estimates an index value for each antenna based on a radio signal transmitted from each of a plurality of distributed antennas, information representing the results of a radio wave simulation, or sensing information for the antennas, and a terminal transmission unit that transmits a radio signal including an index value for each antenna.

[0016] One aspect of the present invention is a communication system comprising a terminal device, a base station, and a plurality of antennas arranged in a distributed manner, wherein the terminal device has an estimation unit that estimates an index value for each antenna based on a radio signal transmitted from each of the plurality of antennas arranged in a distributed manner, or information representing the results of a radio wave simulation, or sensing information for the antennas, and a terminal transmission unit that transmits a radio signal including the index value for each antenna, and the base station has a group control unit that obtains the index value for each antenna by a radio signal including the index value for each antenna, radio wave simulation, or sensing of the antennas, and forms one or more groups from the plurality of antennas based on the index value for each antenna, a communication control unit that forms the cell from the one or more groups by associating the group with communication resources for each cell, and a communication unit that performs communication with a terminal device present in the cell using the antennas that form the group associated with the communication resources of the cell.

[0017] According to the present invention, it is possible to distribute the load among cells while suppressing deterioration in the quality of wireless communication.

[0018] FIG. 1 is a diagram illustrating an example of the configuration of a communication system in a first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a cell in the first embodiment. FIG. 3 is a sequence diagram illustrating an example of the operation of the communication system in the first embodiment. FIG. 4 is a flowchart illustrating an example of the operation of forming an antenna group in the first embodiment. FIG. 5 is a diagram illustrating an example of the configuration of a communication system in a second embodiment. FIG. 6 is a diagram illustrating an example of the hardware configuration of a communication device in each embodiment. FIG. 7 is a diagram illustrating an example of the configuration of a cellular system. FIG. 8 is a diagram illustrating a first example of the configuration of a distributed antenna system. FIG. 9 is a diagram illustrating an example of the configuration of a single frequency network. FIG. 10 is a diagram illustrating a second example of the configuration of a distributed antenna system.

[0019]

[0023] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Fig. 1 is a diagram showing an example of the configuration of a communication system 1 according to the first embodiment. The communication system 1 is a system that performs wireless communication, such as a distributed antenna system.

[0020] The communication system 1 includes a base station 2, Y (Y is an integer equal to or greater than 2) antennas 3, and X (X is an integer equal to or greater than 1) terminal devices 4. The Y antennas 3 are pre-arranged and distributed throughout a communication area. The terminal device 4 includes a terminal receiving unit 41, an estimation unit 42, and a terminal transmitting unit 43. The terminal receiving unit 41 and the terminal transmitting unit 43 include terminal antennas (not shown).

[0021] The base station 2 includes a plurality of communication devices 21 and a switching unit 22 (switch). The communication devices 21 and the switching units 22 may be installed close to each other, or may be installed separately using a connecting line (e.g., optical fiber). The communication devices 21 include a group control unit 211, a communication control unit 212, a transmission unit 213, a signal processing unit 214, a beam control unit 215, and a communication unit 216 (transmitter / receiver). Some of the functional units of the communication devices 21 may be included in the antenna 3. Furthermore, some of the functional units of the terminal device 4 may be included in the antenna 3.

[0022] Like the CU (Central Unit), DU (Distributed Unit), and RU (Radio Unit) in the NR (New Radio) of the fifth generation mobile communication system (5G), some of the functional units (e.g., the signal processing unit 214 and the beam control unit 215) may be separated from the communication device 21 as separate devices.

[0023] The communication device 21 includes communication resources (not shown) for each cell. The communication resources (cell resources) include, for example, a data communication card and a communication infrastructure. The switching unit 22 is connected to the communication resources (not shown) for each cell and to Y antennas 3 that are distributed.

[0024] The base station 2 performs wireless communication with a terminal device 4 present in the cell via an antenna 3 within the cell. The antenna 3 is a transmission / reception point (TRP). The terminal device 4 is a user equipment (UE), such as a smartphone terminal or a tablet terminal. The terminal device 4 performs wireless communication with a communication device 21 via the antenna 3 within the cell.

[0025] The communication device 21 is an aggregation station. The group control unit 211 acquires predetermined information for each antenna 3 as an index value for each antenna 3. The predetermined information is, for example, information representing the results of a radio wave simulation and sensing information (environmental information). The radio wave simulation is, for example, ray tracing. The sensing information is information generated using a sensor, such as positioning information for each antenna 3 generated using sensing technology such as satellite positioning technology, imaging technology, and LiDAR (Light Detection and Ranging). The satellite positioning technology is, for example, GPS (Global Positioning System).

[0026] The group control unit 211 may acquire the index value for each antenna 3 from each antenna 3, for example, using a wireless signal. The group control unit 211 may acquire the index value for each antenna 3 from the terminal transmission unit 43 via each antenna 3. Here, the group control unit 211 acquires the index value for each antenna 3 from the terminal device 4 using a wireless signal (report signal) transmitted from the terminal transmission unit 43. The group control unit 211 may acquire the index value for each antenna 3 from the terminal transmission unit 43 when a beam sweep for a beam search is executed.

[0027] The group control unit 211 may acquire an index value for each antenna 3, for example, by simulating (radio wave simulation) a radio signal transmitted from each of a plurality of dispersedly arranged antennas 3. The group control unit 211 may measure the index value for each antenna 3 in advance via the switching unit 22 using omnidirectional radio waves transmitted from each antenna 3. The group control unit 211 may measure the index value for each antenna 3 in advance via the switching unit 22 by sensing each antenna 3.

[0028] The group control unit 211 forms one or more antenna groups (TRP groups) in advance before a cell is formed from one or more antennas 3. For example, the group control unit 211 selects one or more antennas 3 for each antenna group based on the index value for each antenna 3. The group control unit 211 forms an antenna group from the selected one or more antennas 3.

[0029] The group control unit 211 (group management unit) stores management information for the formed antenna groups. The management information for the antenna groups is, for example, identification information (for example, a management number) for each antenna 3 that forms the antenna group.

[0030] The communication control unit 212 forms (clusters) a cell from one or more antenna groups, with the antenna group being the smallest unit. Since cells are formed in units of antenna groups (multiple antennas whose index values ​​satisfy the conditions to be satisfied) rather than in units of antennas 12, deterioration of the quality of wireless communication is suppressed.

[0031] The communication control unit 212 acquires load information of communication resources for each cell from the communication unit 216. The load information is, for example, the amount of communication traffic in each cell and the number of terminal devices 4 wirelessly connected to the communication resources for each cell (number of connected users). The communication control unit 212 selects one or more antenna groups from among multiple antenna groups for each cell based on the load of communication resources for each cell.

[0032] When a cell is formed, the shape of the cell (the result of the selection of antenna 3) changes dynamically based on the load information of the communication resources for each cell, so that the load is distributed among the cells. Furthermore, since cells are formed in units of antenna groups, the amount of processing (amount of calculation) required for forming a cell can be reduced compared to when cells are formed in units of antenna 3.

[0033] The communication control unit 212 stores management information of the formed cell. The cell management information is, for example, identification information (e.g., management number) of each antenna group that forms the cell. The communication control unit 212 transmits a switching control signal to the switching unit 22 to switch the connection between the communication resource for each cell and the selected antenna 3.

[0034] The transmission unit 213 transmits data signals to and from a higher-level device (not shown) for the base station 2. The transmission unit 213 outputs data signals transmitted from the higher-level device (not shown) to the signal processing unit 214. The transmission unit 213 transmits data signals transmitted from the signal processing unit 214 to the higher-level device (not shown). The transmission unit 213 may transmit data signals and control signals to and from other communication devices 21. The transmission unit 213 may transmit data signals and control signals to and from other base stations 2 (not shown). The transmission unit 213 may transmit data signals and control signals to and from other control nodes (not shown).

[0035] The signal processing unit 214 performs predetermined signal processing related to wireless communication. For example, the signal processing unit 214 performs modulation processing (radio frequency processing) on ​​a data signal input from the transmission unit 213. The signal processing unit 214 outputs the data signal after the modulation processing to the beam control unit 215. For example, the signal processing unit 214 performs demodulation processing on the data signal input from the beam control unit 215. The signal processing unit 214 outputs the data signal after the demodulation processing to the transmission unit 213.

[0036] The beam control unit 215 generates a beamforming signal for controlling the beam formed by the antenna 3. The beamforming signal represents at least one of the phase and amplitude of the beam.

[0037] The communication unit 216 transmits the data signal input from the beam control unit 215 to each antenna 3 via the switching unit 22 based on the beamforming signal. The communication unit 216 transmits the data signal input from the switching unit 22 to the signal processing unit 214 via the beam control unit 215. The communication unit 216 transmits the data signal input from the signal processing unit 214 via the beam control unit 215 to the switching unit 22.

[0038] The switching unit 22 switches the connection relationship between the input and output of the data signal based on a switching control signal from the communication control unit 212. That is, the switching unit 22 switches the connection between the communication resources (not shown) for each cell and the selected antenna 3. The switching unit 22 transmits the data signal input from the communication unit 216 to each antenna 3 based on the connection relationship between the input and output of the data signal. The switching unit 22 transmits the data signal input from each antenna 3 to the communication unit 216 based on the connection relationship between the input and output of the data signal.

[0039] 2 is a diagram illustrating an example of the configuration of a cell 5 in the first embodiment. The communication device 21 includes a communication resource 217 (e.g., a data communication card and a communication infrastructure) for each cell 5. The communication device 21 may include multiple communication resources 217 for each cell 5.

[0040] The communication resource 217 dynamically controls, for each antenna 3, the transmission processing of radio waves (radio signals) in the antennas 3 connected to the communication resource 217 via the switching unit 22. The communication resource 217 dynamically controls, for each antenna 3, the reception processing of signals based on radio waves (radio signals) received by the antennas 3 connected to the communication resource 217 via the switching unit 22.

[0041] The communication device 21 forms an antenna group 51 before forming the cell 5. The communication device 21 forms the cell 5 from one or more antenna groups 51, with the antenna group 51 being the smallest unit.

[0042] Here, the switching unit 22 switches the connection between the communication resource 217 for each cell 5 and each antenna 3 forming the antenna group 51. In Fig. 2, the switching unit 22 connects the communication resource 217-1 to each antenna 3 of the antenna group 51-1 in the cell 5-1. The switching unit 22 connects the communication resource 217-2 to each antenna 3 of the antenna group 51-2 in the cell 5-2. The switching unit 22 connects the communication resource 217-3 to each antenna 3 of the antenna group 51-3 in the cell 5-3.

[0043] The group control unit 211 forms an antenna group 51 made up of one or more antennas 3 in advance before a cell 5 is formed. Here, n antennas 3 to be connected to communication resources 217 for each cell 5 are selected based on a selection condition.

[0044] The selection condition is, for example, determined in advance as a condition that must be satisfied by the index value "k" of the relationship between the antennas 3. The relationship between the antennas 3 is, for example, the connectivity of communication between each antenna 3 and a common terminal device 4. The relationship between the antennas 3 may also be, for example, the interference of radio waves between multiple antennas 3. An antenna group 51 is formed from the n antennas 3 selected based on the selection condition.

[0045] The index value of the relationship between the antennas 3 is, for example, an index value from the perspective of spatial multiplexing quality. The index value from the perspective of spatial multiplexing quality is, for example, an index value of coherence between the antennas 3. The index value of coherence between the antennas 3 is, for example, the distance between the antennas 3, the overlap rate of the communication areas for each antenna 3, a spatial correlation value, a correlation value of the reception strength (reception level) of the wireless signal, and a correlation value of the reception strength in multiple beam directions. The index value is compared with, for example, a threshold value.

[0046] The index value of the relationship between the antennas 3 may be, for example, an index value in terms of connectivity. The index value in terms of connectivity is, for example, an index value representing the degree to which radio waves between the antennas 3 are likely to be simultaneously blocked. The index value representing the degree to which radio waves are likely to be simultaneously blocked is, for example, an overlap rate of the angles of arrival (AoA) of the same radio signals transmitted from the terminal devices 4 to the antennas 3 using radio waves, a correlation value of the reception levels of the radio signals, and a correlation value of the reception strengths in multiple beam directions.

[0047] The selection conditions may combine multiple index values ​​(e.g., an index value from the perspective of spatial multiplexing quality and an index value from the perspective of connectivity). The selection conditions may change the index value depending on, for example, the time period and the communication area. The selection conditions may set an upper limit "N" on the number of antennas 3 for each antenna group 51. Furthermore, the group control unit 211 may not only add antennas 3 to the antenna group 51 based on the selection conditions, but also add antennas 3 to the antenna group 51 based on instructions and operations from the operator of the base station 2.

[0048] The group control unit 211 may add only antennas 3 that satisfy the selection conditions to the antenna group 51. The group control unit 211 may add antennas 3 to the antenna group 51 so that at least one antenna 3 in the antenna group 51 satisfies the selection conditions.

[0049] The communication device 21 may dynamically change one or more antenna groups 51 forming a cell 5 at regular intervals. The communication device 21 may dynamically change one or more antenna groups 51 forming a cell 5 when a predetermined condition is satisfied. For example, the communication device 21 may dynamically change one or more antenna groups 51 forming a cell 5 based on load information of the communication resources 217 for each cell 5. For example, the communication device 21 may dynamically change one or more antenna groups 51 forming a cell 5 based on instructions and operations from an operator of the base station 2.

[0050] In addition, the communication device 21 may form an antenna cluster 52 (TRP cluster, access point cluster) formed from one or more antennas 3 (access points) of all antennas 3 in the same cell 5, independently of the antenna group 51, for a terminal device "UE" present in that cell 5. For example, the communication device 21-1 may form an antenna cluster 52 formed from antennas 3-13 and 3-14 in cell 5-2, independently of the antenna group 51-2, for a terminal device 4-3 present in cell 5-2. Since the freedom of selection of antennas 3 constituting the antenna cluster 52 is not limited to the antenna group 51, the possibility of limiting the spatial multiplexing number is reduced. Furthermore, the possibility of a decrease in connectivity between different antenna groups 51 is reduced. For example, even if terminal device 4-3 moves from the communication area of ​​antenna group 51-2-1 to the communication area of ​​antenna group 51-2-2, terminal device 4-3 can improve connectivity with antennas 3-13 and 3-14 in antenna cluster 52 that spans antenna groups 51-2-1 and 51-2-2.

[0051] When multiple cells 5 are formed by multiple communication resources 217, one of the multiple communication devices 21 may be a parent device, and the remaining communication devices 21 may be child devices. The parent communication device 21 communicates with the child communication devices 21, for example, using the transmission unit 213. The parent communication device 21 may collectively form the cells 5 of the child devices.

[0052] In addition, a higher-level device (not shown) for the base station 2, a control device (not shown) separate from the communication device 21, or the switching unit 22 may perform the process of forming the cell 5 instead of the communication device 21.

[0053] Next, an example of the operation of the communication system 1 will be described. FIG. 3 is a sequence diagram showing an example of the operation of the communication system 1 in the first embodiment. In FIG. 3, as an example, the communication device 21-1 is the parent device, and the communication device 21-2 is the child device. The communication device 21-1 transmits a reference signal "#1" to the terminal device 4 using the antenna 3 connected to the communication device 21-1 via the switching unit 22. The reference signal includes identification information of the antenna 3 (step S101-1). The communication device 21-2 transmits a reference signal "#2" to the terminal device 4 using the antenna 3 connected to the communication device 21-2 via the switching unit 22 (step S101-2). Note that the antenna 3 may transmit the reference signal while changing the beam direction by performing a beam sweep.

[0054] The terminal receiver 41 acquires reference signals (radio signals) transmitted from each of the antennas 3 distributed throughout the communication area. The estimation unit 42 estimates, for each antenna 3, the reception strength (received power), signal-to-noise power ratio, the time length from the transmission time of the radio signal to the reception time of the radio signal, the round trip time (RTT) of the radio signal, channel state information (CSI) based on the radio signal, position information of the antenna 3, and the direction of arrival (AoA) of the radio signal, using the received reference signals (radio signals). The estimation unit 42 may estimate these for each antenna 3 based on information representing the results of a radio wave simulation such as ray tracing. The estimation unit 42 may also estimate these for each antenna 3 by sensing the antenna 3. The terminal transmitter 43 transmits a report signal "#1" of the estimation result to the communication device 21-1 (step S102-1). The report signal may include a value of the estimation result (estimated index value) or an index representing a classification result of the value of the estimation result.

[0055] Similarly, the estimation unit 42 estimates the reception strength, etc. of the wireless signal transmitted from the antenna 3 for each antenna 3 using the received reference signal. The estimation unit 42 may estimate the reception strength, etc. of the wireless signal transmitted from the antenna 3 for each antenna 3 by radio wave simulation. The terminal transmission unit 43 transmits a report signal "#2" of the estimation result to the communication device 21-2 (step S102-2-1). The communication device 21-2 (slave) transfers the report signal "#2" of the estimation result to the communication device 21-1 (parent device) using the transmission unit 213-2 (step S102-2-2).

[0056] The estimation unit 42 (generation unit) may include, in the report signal, not only information on the estimation result but also predetermined feedback information. The feedback information is, for example, information on the planned communication traffic volume, the predicted traffic volume, the planned requested amount of resource allocation, and the predicted requested amount of resource allocation in the terminal device 4. The feedback information may include an index indicating the classification result of each of these pieces of information.

[0057] The communication device 21 may specify the timing at which the terminal device 4 transmits the report signal to the terminal device 4. Here, the communication device 21 may specify the timing at which the terminal device 4 transmits the report signal to the terminal device 4 so as to coincide with the timing at which the receiving beam is formed by the antenna 3.

[0058] Furthermore, the estimation unit 42 may generate feedback information for each beam formed by the antenna 3. The estimation unit 42 may aggregate the feedback information generated for each beam. The terminal transmitting unit 43 may transmit the aggregated feedback information to the antenna 3 in accordance with the timing at which a beam having the highest reception strength of the radio signal at the terminal receiving unit 41 is formed among the beams formed by the antenna 3.

[0059] If the communication system 1 includes a control device (not shown) separate from the communication device 21, the communication device 21 may transfer the report signal to the control device (not shown). If a host device (not shown) for the base station 2 forms a cell 5, the communication device 21 may transfer the report signal to the host device (not shown).

[0060] The communication device 21-1 (parent device) aggregates the report signals received from each terminal device 4. Based on the aggregated report signals, the communication device 21-1 selects one or more antennas 3 for each antenna group 51. The communication device 21-1 forms each antenna group 51 from the one or more antennas 3 selected for each antenna group 51 (step S103).

[0061] The communication device 21-1 (parent device) forms each cell 5 with the antenna group 51 as the smallest unit based on the aggregated report signal (step S104). The communication device 21-1 transmits a switching control signal to the switching unit 22. Based on the switching control signal, the switching unit 22 switches the connection between the communication resource 217 for each cell 5 and the selected antenna 3 (step S105).

[0062] Note that even if the communication device 21-1 has acquired a report signal, it may skip steps S103 to S105 and execute step S107. For example, after executing step S102, the communication device 21-1 may skip steps S103 and S105, or may skip steps S104 and S105.

[0063] The communication device 21-1 transmits the data signal "#1" to the terminal device 4-1 via, for example, the antenna 3-1 and the antenna 3-2 connected to the communication resource 217-1 by the switching unit 22 (step S106-1).

[0064] The communication device 21-1 may form an antenna cluster 52 (TRP cluster) formed from a plurality of antennas 3 in the cell 5 for the terminal device 4 present in the cell 5, independently of the antenna group 51. In addition, the communication device 21-2 transmits a data signal "#2" to the terminal device 4-3 via, for example, the antennas 3-9 and 3-10 connected to the communication resource 217-2 by the switching unit 22 (step S106-2).

[0065] For example, the terminal device 4-1 transmits a data signal to the communication device 21-1 via the antennas 3-1 and 3-2 connected to the communication resource 217-1 by the switching unit 22 (step S107-1). For example, the terminal device 4-3 transmits a data signal to the communication device 21-2 via the antennas 3-9 and 3-10 connected to the communication resource 217-2 by the switching unit 22 (step S107-2).

[0066] 4 is a flowchart showing an example of an operation for forming an antenna group 51 in the first embodiment. The group control unit 211 calculates an index value "k ｘｙ " is acquired from antenna 3 "x" or antenna 3 "y" (another antenna) as an example of a value in the selection condition. The group control unit 211 acquires the index value "k ｘｙ " may be obtained from the terminal device 4 "y" using a report signal as illustrated in FIG. 3 (step S201).

[0067] The group control unit 211 initializes a variable "i" representing the number (control number) of the antenna group 51 to be determined to "1." The group control unit 211 initializes a variable "n" representing the number of antennas 3 added to the antenna group 51 "#i" to "0" (step S202).

[0068] The group control unit 211 selects one antenna 3 (initial antenna) that will be the basis for the antenna group 51 “#i” from among the antennas 3 that have not been added to any of the antenna groups 51 .

[0069] The group control unit 211 may randomly select one base antenna 3 from among the antennas 3 that have not been added to any antenna group 51. The group control unit 211 may select one base antenna 3 by giving priority to the antenna 3 with the widest communication area. The group control unit 211 may select one base antenna 3 by giving priority to the antenna 3 with the smallest assigned number (management number). The group control unit 211 may select one base antenna 3 based on instructions and operations from the operator of the base station 2.

[0070] If the variable "i" representing the number of the antenna group 51 is "1", the group control unit 211 initializes the variable "M" representing the number of antennas 3 that remain unadded (remaining addition candidates) to "Y", the total number of antennas 3. On the other hand, if the variable "i" is not "1", the group control unit 211 subtracts "n", the number of antennas 3 that have been added to the antenna group 51 "#(i-1)", from the variable "M" (step S203).

[0071] The group control unit 211 initializes the variable "n", which indicates the number of antennas 3 added to the antenna group 51 "#i", to "1". The group control unit 211 also initializes the variable "j", which indicates the number of the antenna 3 to be determined, to "1" (step S204).

[0072] If the number of antennas 3 "n" added to antenna group 51 "#i" does not reach the upper limit "N" of the number of antennas 3 that form antenna group 51 "#i" (n<N), and if there are antennas 3 (addition candidates) remaining for which the determination of whether to add them to antenna group 51 "#i" has not been performed (j≦M), the group control unit 211 repeatedly executes each step from step S205 to step S209.

[0073] The group control unit 211 determines the index value "k" of the antenna 3 "#j". ｘｙ The selection condition is determined based on a predetermined threshold and the index value "k ｘｙ" is a condition expressed using the comparison result with ", and may be, for example, a condition that the index value is less than a threshold value, or a condition that the index value is equal to or greater than a threshold value. The selection condition may be expressed, for example, using an evaluation function that takes the index value as an argument. The evaluation function may be expressed using multiple index values. In the evaluation function, each index value of the multiple index values ​​may be weighted (step S205).

[0074] The index value of antenna 3 "#j" is "k ｘｙ does not satisfy the selection condition (step S205: No), the group control unit 211 proceeds to step S207.

[0075] The index value of antenna 3 "#j" is "k ｘｙ If it is determined that "#j" satisfies the selection condition (step S205: Yes), the group control unit 211 adds antenna 3 "#j" to antenna group 51 "#i". The group control unit 211 adds "1" to variable "n", which represents the number of antennas 3 added to antenna group 51 "#i" (step S206). The group control unit 211 increments variable "j" so that variable "j" represents the number of antenna 3 that will be the next target of determination (step S207).

[0076] The group control unit 211 determines whether the variable "j" representing the number of the antenna 3 is equal to or less than the variable "M" (step S208). If it is determined that the variable "j" representing the number of the antenna 3 exceeds the variable "M" (step S208: No), the group control unit 211 proceeds to step S210.

[0077] If it is determined that the variable "j" representing the number of antenna 3 is equal to or less than the variable "M" (step S208: Yes), the group control unit 211 determines whether or not antenna 3 "#j" is one of the candidates for addition (antennas 3 that remain unadded) (step S209).If it is determined that antenna 3 "#j" is not one of the candidates for addition (step S209: No), the group control unit 211 proceeds to step S207.

[0078] If it is determined that antenna 3 "#j" is one of the candidates for addition (step S209: Yes), the group control unit 211 determines whether the number "n" of antennas 3 added to antenna group 51 "#i" is less than the upper limit "N" as a repetition condition (step S210). Note that the group control unit 211 may not only determine whether the number "n" of antennas 3 is less than the upper limit "N", but also determine whether an addition repetition condition is satisfied. Furthermore, whether the number "n" of antennas 3 is less than the upper limit "N" and the repetition condition may be weighted.

[0079] If it is determined that the number "n" of antennas 3 added to antenna group 51 "#i" is less than the upper limit "N" (step S210: Yes), the group control unit 211 returns the process to step S205.

[0080] If it is determined that the number "n" of antennas 3 added to antenna group 51 "#i" is equal to or greater than the upper limit "N" (step S210: No), the group control unit 211 determines whether the result of subtracting the number "n" of antennas 3 added to antenna group 51 "#i" from variable "M" is less than 1. That is, the group control unit 211 determines whether there are any remaining antennas 3 (addition candidates) for which determination of addition to antenna group 51 "#i" has not been performed (step S211). The group control unit 211 increments variable "i" so that variable "i" represents the number of the antenna group 51 to be determined next (step S212). The group control unit 211 returns to step S203.

[0081] As described above, the estimation unit 42 estimates the index value for each antenna 3 based on predetermined information. For example, the estimation unit 42 estimates the index value for each antenna 3 based on radio signals transmitted from each of a plurality of antennas 3 distributed throughout a communication area. The estimation unit 42 may estimate the index value for each antenna 3 based on radio wave simulation such as ray tracing of the transmitted radio signals. The estimation unit 42 may estimate the index value for each antenna 3 based on sensing information (e.g., information about the placement of the antennas 3) generated using sensing technologies such as satellite positioning technology, imaging technology, and LiDAR. The terminal transmission unit 43 may transmit a radio signal including the index value for each antenna 3 to the base station 2 via the antenna 3 and the switching unit 22.

[0082] The group control unit 211 acquires a radio signal including an index value for each antenna 3, for example, via the communication unit 216. The group control unit 211 may acquire the index value for each antenna 3, for example, by simulating (radio wave simulation) a radio signal transmitted from each of a plurality of antennas 3 that are distributed in a distributed manner. The group control unit 211 may acquire the index value for each antenna 3, for example, by sensing each antenna 3. The group control unit 211 forms one or more antenna groups 51 (groups) from the plurality of antennas 3 based on the index value for each antenna 3. The index value for each antenna 3 is, for example, an index value of the relationship between the antenna 3 and other antennas. The index value for each antenna 3 may also be, for example, an index value of the relationship between the antenna 3 and a terminal device 4.

[0083] The communication control unit 212 forms a cell 5 from one or more antenna groups 51 by associating the antenna groups 51 with communication resources 217. For example, the communication control unit 212 forms a cell 5 from one or more antenna groups 51 by associating the antenna groups 51 with communication resources 217 based on the load of the communication resources 217 for each cell 5. The load of the communication resources 217 is not limited to being expressed by a specific index as long as it is possible to distribute the load among cells. For example, the load of the communication resources 217 may be expressed by the amount of communication traffic in each cell 5 or by the number of terminal devices 4 wirelessly connected to the communication resources 217 for each cell 5. The communication unit 216 performs communication with the terminal devices 4 present in the cell 5 using the antennas 3 that form the antenna group 51 associated with the communication resources 217 of the cell 5.

[0084] This makes it possible to distribute the load between cells while suppressing deterioration in the quality of wireless communication.

[0085] For example, n antennas 3 connected to communication resources (cell resources) of a cell 5 are selected based on a selection condition. An antenna group 51 is formed from the selected n antennas 3. The index values ​​of one or more antennas 3 forming the antenna group 51 satisfy the selection condition. Since a cell 5 is formed in units of such antenna groups 51, deterioration in the quality of wireless communication is suppressed.

[0086] For example, the shape of the cells 5 changes dynamically in units of antenna groups 51 based on load information of the communication resources 217 for each cell 5, thereby distributing the load among the cells 5. Furthermore, since the cells 5 are formed in units of antenna groups 51, the amount of processing required to form the cells 5 can be reduced compared to when the cells 5 are formed in units of antennas 3.

[0087] Second Embodiment The second embodiment differs from the first embodiment mainly in that the communication device 21 includes a switching unit 22. The second embodiment will be described mainly focusing on the differences from the first embodiment.

[0088] 5 is a diagram showing an example of the configuration of a communication system 1 in the second embodiment. The communication device 21 may include a switching unit 22. The switching unit 22 is connected to communication resources for each cell 5 and Y antennas 3. The switching unit 22 switches the connection relationship between the input and output of data signals based on a switching control signal from the communication control unit 212. That is, the switching unit 22 switches the connection between the communication resources 217 for each cell 5 and the selected antenna 3.

[0089] This makes it possible to suppress an increase in the cost of the base station 2 and to suppress deterioration in the quality of wireless communication, while distributing the load among cells.

[0090] (Hardware Configuration) FIG. 6 is a diagram illustrating an example of the hardware configuration of the communication device 21 in each embodiment. The communication device 21 is realized as software by a processor 101, such as a CPU (Central Processing Unit), executing a program stored in a storage device 103 having a non-volatile recording medium (non-transitory recording medium) and a memory 102. The program may be recorded on a computer-readable recording medium. Examples of computer-readable recording media include portable media such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), and a CD-ROM (Compact Disc Read Only Memory), and non-transitory recording media such as a hard disk or a solid-state drive (SSD) built into a computer system. The communication unit 216 executes predetermined communication processing.

[0091] The communication device 21 may be realized using hardware including an electronic circuit (electronic circuit or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0092] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0093] For example, "base station," "radio base station," "NodeB," "eNodeB," "gNodeB," "access point," "cell," "macrocell," "small cell," "femtocell," and "picocell" can be read interchangeably.

[0094] For example, "antenna," "TRP (Transmission and Reception Point)," "Remote Radio Unit (RRU)," "Radio Unit (RU)," "Distributed Antenna (DA)," "panel," "TP (Transmission Point)," and "RP (Reception Point)" can be read interchangeably.

[0095] The present invention is applicable to distributed antenna systems.

[0096] 1...communication system, 2...base station, 3...antenna, 4...terminal device, 5...cell, 11...antenna, 12...antenna, 21...communication device, 22...switching unit, 41...terminal receiving unit, 42...estimation unit, 43...terminal transmitting unit, 51...antenna group, 52...antenna cluster, 211...group control unit, 212...communication control unit, 213...transmission unit, 214...signal processing unit, 215...beam control unit, 216...communication unit, 217...communication resource

Claims

1. A base station comprising: a group control unit that forms one or more groups from multiple antennas based on an index value for each antenna; a communication control unit that forms a cell from the one or more groups by associating the group with communication resources for each cell; and a communication unit that performs communication with a terminal device present in the cell using the antennas that form the group associated with the communication resources of the cell.

2. The base station according to claim 1, wherein the index value for each antenna is an index value of the relationship between the antenna and another antenna, or an index value of the relationship between the antenna and the terminal device.

3. A terminal device comprising: an estimation unit that estimates an index value for each of a plurality of antennas that are distributed and arranged based on a radio signal transmitted from each of the antennas, information representing the results of a radio wave simulation, or sensing information for the antennas; and a terminal transmission unit that transmits a radio signal including an index value for each of the antennas.

4. A communication system comprising a terminal device, a base station, and a plurality of antennas arranged in a distributed manner, wherein the terminal device has an estimation unit that estimates an index value for each antenna based on a radio signal transmitted from each of the plurality of antennas arranged in a distributed manner, or information representing the results of a radio wave simulation, or sensing information for the antennas, and a terminal transmission unit that transmits a radio signal including the index value for each antenna, and the base station has a group control unit that obtains the index value for each antenna by the radio signal including the index value for each antenna, radio wave simulation, or sensing of the antennas, and forms one or more groups from the plurality of antennas based on the index value for each antenna, a communication control unit that forms the cell from the one or more groups by associating the group with communication resources for each cell, and a communication unit that performs communication with a terminal device present in the cell using the antennas that form the group associated with the communication resources of the cell.

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