Base station and connection switching device

Abstract

This base station comprises: one or more communication devices that include communication resources for each cell and that form a plurality of cells by means of a plurality of distributed antennas; a plurality of switching units that switch connection relationships between the communication resources included in the one or more communication devices and the plurality of antennas; and one or more combining / distributing units that combine or distribute input signals between the plurality of switching units.　

Description

Base station and connection switching device

[0001] The present invention relates to a base station and a connection switching device.

[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, so distributed antenna systems that can improve communication connectivity even in high frequency bands have been studied (see, for example, Non-Patent Document 1).

[0004] Before explaining the distributed antenna system, a general cellular system will be described. FIG. 5 is a diagram showing an example of the configuration of a cellular system. A base station in a cellular system is composed of a radio digital processing unit (BBU: Base Band Unit) and one or more remote radio heads (RRH: Remote Radio Head). The radio digital processing unit performs digital processing for wireless communication in a layer above the physical layer. The remote radio head performs radio frequency (RF) processing. The remote radio head may also perform part of the processing in the physical layer. The antenna 11 is a transmission and reception point (TRP: Transmission and Reception Point). The antenna 11 may extend further from the remote radio head or may be integrated with the remote radio head.

[0005] 5, the antennas 11-1 to 11-3 form different "cells #1" to #3, and transmit and receive radio signals to and from the terminal device "UE" located within the cells. In this way, the antennas 11-1 to 11-3 are distributed and arranged in different locations, thereby forming a wide communication area.

[0006] Fig. 6 is a diagram showing a first configuration example of a distributed antenna system. In Fig. 6, multiple antennas 12 (distributed antennas) are provided for one extension unit. As shown in Fig. 6, multiple antennas 12 (distributed antennas) extending further from one extension unit cover a common cell. For example, antennas 12-1-1 and 12-1-2 extending further from a certain extension unit cover cell "#1."

[0007] In a distributed antenna system, the communication area of ​​each cell can be expanded compared to a cellular system by using multiple antennas 12 extending from the extension portion. This allows the communication distance to be shortened while ensuring the line of sight of radio waves. In addition, the communication capacity can be increased by having multiple antennas 12 covering a common cell cooperate to perform MIMO (Multiple-Input Multiple-Output) communication.

[0008] Also, as shown in Fig. 7, a single frequency network (SFN) can be configured in which a single cell is expanded by multiple sets of extensions and antennas 12. Fig. 7 is a diagram showing an example of the configuration of a single frequency network. Fig. 7 shows how a single cell "#1" is expanded by using multiple sets of extensions and antennas 12.

[0009] Unlike the distributed antenna system shown in Figure 6, which separates the wireless digital processing unit and the extension unit, a distributed antenna system has also been proposed in which functions are consolidated into a communication device and multiple antennas 12 are extended. Figure 8 is a diagram showing a second configuration example of a distributed antenna system. The communication device is provided with communication resources for each cell. The communication resources (cell resources) represent the processing capabilities required to form one cell (e.g., the number of connected users, the number of MIMO layers, baseband processing capabilities, fronthaul capacity, etc.) and are included, for example, in function unit cards and circuit boards that constitute various function units of the communication device. In Figure 8, multiple antennas 12 are connected to each communication resource via a switching unit (switch).

[0010] 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 a load index (such as the traffic volume or number of connected users of each cell). By using such a cell clustering method, the communication device can form cells and achieve load balancing among the communication devices and cell resources.

[0011] “DOCOMO 6G White Paper 5G Evolution and 6G Version 5.0”, [online], NTT Docomo, Inc., [Retrieved August 8, 2024], Internet <URL: https: / / www.docomo.ne.jp / english / binary / pdf / corporate / technology / whitepaper_6g / DOCOMO_6G_White_PaperEN_v5.0.pdf> , January 2023.

[0012] 5, 6, and 7, the communication load may be concentrated on the communication resources of a specific extension and a specific cell due to the amount of communication traffic and the uneven distribution of terminal devices (UE). Also, in cells and time periods where the amount of communication traffic or the number of terminal devices wirelessly connected to the extension is low, there is a high possibility that surplus communication resources will occur, which may result in waste in terms of power consumption, etc.

[0013] In contrast, in the distributed antenna system shown in Figure 8, the load of communication resources can be distributed between cells. However, as the area expands, the amount of communication resources required increases, resulting in increased costs and power consumption for forming the service area. Furthermore, due to restrictions on the number of physical ports of the communication devices, the number of communication devices required to expand the communication area also increases. As such, the distributed antenna system shown in Figure 8 has the problem of being unable to expand the communication area while reducing the amount of communication resources.

[0014] In view of the above circumstances, an object of the present invention is to provide a technology that can expand a communication area while reducing the amount of communication resources.

[0015] One aspect of the present invention is a base station comprising one or more communication devices each having communication resources for each cell and forming one or more cells using a plurality of antennas arranged in a distributed manner, the communication resources provided by the one or more communication devices, a plurality of switching units that switch the connection relationship with the plurality of antennas, and one or more combining / distributing units that combine or distribute input signals between the plurality of switching units.

[0016] One aspect of the present invention is a connection switching device connected to one or more base stations, which is a communication device provided at the one or more base stations, and which includes communication resources for each cell and one or more communication devices that form one or more cells using a plurality of antennas that are distributedly arranged, a plurality of switching units that switch the connection relationship with the plurality of antennas, and one or more combining / distributing units that combine or distribute input signals between the plurality of switching units.

[0017] According to the present invention, it is possible to expand the communication area while reducing the amount of communication resources.

[0018] Fig. 1 is a diagram showing a configuration example of a communication system in an embodiment. Fig. 2 is a diagram showing a configuration example of a base station in a first modified example of an embodiment. Fig. 3 is a diagram showing a configuration example of a communication system in a third modified example of an embodiment. Fig. 4 is a diagram showing a hardware configuration example of a communication device in an embodiment. Fig. 5 is a diagram showing a configuration example of a cellular system. Fig. 6 is a diagram showing a first configuration example of a distributed antenna system. Fig. 7 is a diagram showing a configuration example of a single frequency network. Fig. 8 is a diagram showing a second configuration example of a distributed antenna system.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] 1 is a diagram showing an example of the configuration of a communication system 100 according to an embodiment. The communication system 100 is a system that performs wireless communication, such as a distributed antenna system.

[0021] The communication system 100 includes a plurality of communication devices 1, a connection switching device 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 plurality of communication devices 1 and the connection switching device 2 constitute a base station B. In FIG. 1, the communication devices 1 constituting the base station B are two communication devices 1-1 and 1-2, but the number of communication devices 1 is not particularly limited. The Y antennas 3 may be pre-arranged and distributed throughout the communication area, or may be installed additionally.

[0022] 7 , the communication system 100 in the embodiment has a configuration in which functions are concentrated in the communication device 1 and an antenna 3 is extended. The communication devices 1 and the connection switching device 2 may be installed close to each other (for example, in the same location), or may be installed apart from each other using a connecting line (for example, optical fiber).

[0023] The communication devices 1-1 and 1-2 have the same configuration. The communication device 1 includes a communication control unit 110, a transmission unit 120, a signal processing unit 130, a beam control unit 140, and a communication unit 150 (transmitter / receiver). Some of the functional units of the communication device 1 (for example, the beam control unit 140 and the communication unit 150) may be included in the antenna 3.

[0024] In addition, some of the functions of the communication device 1 (for example, the signal processing unit 130) may be separated from the communication device 1 as separate devices, such as a CU (Central Unit), DU (Distributed Unit), and RU (Radio Unit) in the NR (New Radio) of the fifth generation mobile communication system (5G).

[0025] The communication device 1 is a central station. The communication device 1 includes communication resources (not shown) for each cell. The communication resources (cell resources) are, for example, function cards and circuit boards. Furthermore, the communication device 1 has a function that can dynamically control the area of ​​each cell on an antenna 3 basis based on index values ​​such as the traffic status of each cell and the number of connected users.

[0026] 1, when cell clustering is performed across multiple communication devices 1, one communication device 1 (e.g., communication device 1-1) may act as a parent device and other communication devices 1 (e.g., communication device 1-2) may act as child devices, with the parent communication device 1-1 performing the cell clustering collectively, or an upper node, a control device other than the communication device 1, or a connection switching device 2 may perform overall control to perform the cell clustering. In the following explanation, it is assumed that the parent communication device 1-1 performs the cell clustering collectively.

[0027] The base station B 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 the communication device 1 via the antenna 3 within the cell.

[0028] The connection switching device 2 is connected to communication resources (not shown) for each cell and Y antennas 3 that are distributed. The connection switching device 2 switches the antennas 3 connected to each communication resource provided by the communication device 1 in response to an instruction from the communication device 1. In this embodiment, the connection switching device 2 includes a switch as well as a multiplexer / distributor that combines or distributes uplink signals and downlink signals, respectively, as a mechanism for switching the connection between each communication resource and each antenna 3. This makes it possible to set a single frequency network for some or all cells. This makes it possible to achieve flexible resource control in the communication device 1 and alleviate constraints on the number of physical ports.

[0029] In cell clustering in a communication device 1, a cell set as a single frequency network can form multiple communication areas using a single communication resource (cell resource). However, because a cell is formed using only a single communication resource (cell resource) for a wide communication area, there is a concern that throughput may decrease as the number of terminal devices 4 accommodated increases due to the expansion of the communication area. Taking such a trade-off into consideration, the present invention makes it possible to increase the options for forming cells in cell clustering according to resource requirements.

[0030] Furthermore, the multiplexer / distributor provided in the connection switching device 2 makes it possible to expand the upper limit of the number of connections of the antennas 3, which is limited by the number of physical ports of the communication device 1. Therefore, the present invention makes it possible to improve the flexibility and scalability of cell clustering control, such as realizing cell clustering specialized for area deployment (TRP deployment).

[0031] [Configuration of communication device 1] The communication control unit 110 acquires load information of communication resources for each cell from the communication unit 150. 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 110 dynamically controls the area of ​​each cell for each antenna 3 based on the load information of communication resources for each cell.

[0032] Furthermore, the communication control unit 110 may dynamically control the plurality of antennas 3 to form a single frequency network.

[0033] When a cell is formed, the shape of the cell (the result of the selection of the antenna 3) changes dynamically based on the load information of the communication resources of each cell, so that the load is distributed among the cells.

[0034] The communication control unit 110 stores management information for the formed cells. The cell management information is, for example, identification information (e.g., management number) for each antenna forming the cell. The communication control unit 110 transmits a switching control signal for switching the connection between the communication resources for each cell and the selected antenna 3 to the connection switching device 2 via the signal processing unit 130 or the like. In response to this, the communication control unit 110 instructs the connection switching device 2 to control switching of the connection with each antenna 3.

[0035] The communication control unit 110 also controls the allocation of communication resources to each terminal device 4 .

[0036] The transmission unit 120 transmits data signals to and from a higher-level device (not shown) for the base station B. The transmission unit 120 outputs the data signals transmitted from the higher-level device (not shown) to the signal processing unit 130. The transmission unit 120 transmits the data signals transmitted from the signal processing unit 130 to the higher-level device (not shown). The transmission unit 120 may transmit data signals and control signals to and from another communication device 1. The transmission unit 120 may transmit data signals and control signals to and from another base station B (not shown). The transmission unit 120 may transmit data signals and control signals to and from another control node (not shown).

[0037] The signal processing unit 130 performs signal processing on the input signal. The signal processing unit 130 performs modulation processing (radio frequency processing) on, for example, a data signal input from the transmission unit 120 or a switching control signal input from the communication control unit 110. The signal processing unit 130 outputs the data signal or switching control signal that has been modulated to the beam control unit 140. The signal processing unit 130 performs demodulation processing on, for example, a data signal input from the beam control unit 140. The signal processing unit 130 outputs the data signal that has been demodulated to the transmission unit 120.

[0038] The beam control unit 140 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.

[0039] Based on the beamforming signal, the communication unit 150 transmits the data signal input from the beam control unit 140 to each antenna 3 via the connection switching device 2. The communication unit 150 transmits the data signal input from the connection switching device 2 to the signal processing unit 130 via the beam control unit 140. The communication unit 150 transmits the switching control signal input from the signal processing unit 130 via the beam control unit 140 to the connection switching device 2.

[0040] [Configuration of connection switching device 2] The connection switching device 2 includes a switching unit 21, a plurality of combining / distributing units 22-1 to 22-2, and a switching unit 23. While Fig. 1 shows a configuration in which the connection switching device 2 includes a plurality of combining / distributing units 22-1 to 22-2, it is sufficient for the connection switching device 2 to include one or more combining / distributing units 22.

[0041] The switching unit 21 switches the connection relationship between the input and output based on a switching instruction signal transmitted from the communication device 1. Specifically, the switching unit 21 switches the connection relationship so that a data signal transmitted from the communication device 1 can be output from an output destination connected to a desired antenna 3. In other words, the switching unit 21 switches the connection relationship between the communication resources of the communication device 1 and the antenna 3.

[0042] The switching unit 21 outputs the data signal transmitted from the communication device 1 to the combining / distributing unit 22 or the switching unit 23. For example, when transmitting the same data signal to multiple antennas 3, the switching unit 21 may output the data signal to the combining / distributing unit 22. When transmitting the same data signal to multiple antennas 3, for example, the switching unit 21 may transmit the data signal to multiple antennas 3 that constitute a single frequency network, or when diversity transmission (reception in the case of uplink) is performed. For example, when transmitting different data signals to each antenna 3, the switching unit 21 may output each data signal to the switching unit 23. When transmitting different data signals to each antenna 3, for example, the switching unit 21 may transmit the data signals to antennas 3 of different cells.

[0043] The switching unit 21 transmits the data signal input from the combining / dividing unit 22 or the switching unit 23 to the communication unit 150 based on the connection relationship between the input and output of the data signal. The switching unit 21 is one aspect of a first switching unit.

[0044] The combining / distributing unit 22 is provided between the switching unit 21 and the switching unit 23. The combining / distributing unit 22 copies and distributes an input signal, or combines multiple input signals. For example, the combining / distributing unit 22 copies and distributes a data signal transmitted from the communication device 1 and outputs the resulting signal to the switching unit 23. Also, for example, the combining / distributing unit 22 combines multiple signals output from the switching unit 23 and outputs the resulting signal to the switching unit 21.

[0045] For example, the combining / distributing unit 22 may transmit a different signal for each port for a control signal called C-plane, rather than copying the entire signal for the purpose of beam control that identifies the antenna 3. Also, for example, the combining / distributing unit 22 may transmit a different signal for each port for a monitoring signal called M-plane, rather than copying the entire signal for the purpose of monitoring that identifies the antenna 3.

[0046] The switching unit 23 switches the connection relationship between the input and output based on a switching instruction signal transmitted from the communication device 1. Specifically, the switching unit 23 switches the connection relationship so that the data signal transmitted from the communication device 1 can be output from the output destination connected to the desired antenna 3. In other words, the switching unit 23 switches the connection relationship between the communication resources of the communication device 1 and the antenna 3.

[0047] The switching unit 23 transmits the data signals distributed by the combining / distributing unit 22 to different antennas 3. Furthermore, the switching unit 23 transmits the data signals output from the switching unit 21 to each antenna 3 based on the connection relationship between the input and output of the data signals. The switching unit 23 outputs the data signals input from each antenna 3 constituting the single frequency network to the combining / distributing unit 22. Furthermore, the switching unit 23 outputs the data signals input from each antenna 3 of different cells to the switching unit 21. The switching unit 23 is one aspect of the second switching unit.

[0048] 1, the present invention is characterized in that the combining / distributing unit 22 is provided between the switching unit 21 and the switching unit 23. With this configuration, it becomes possible to change the cell size in units of antennas 3 and realize cell clustering including single-frequency networks, regardless of the number of output ports of the communication device 1.

[0049] According to the communication system 100 configured as described above, the base station B includes a communication device 1 that has communication resources for each cell and forms multiple cells using multiple antennas 3 that are distributedly arranged, a switching unit 21 and a switching unit 23 that switch the connection relationship between the communication resources of the communication device 1 and the multiple antennas 3, and a combining / distributing unit 22 that combines or distributes input signals between the switching unit 21 and the switching unit 23.

[0050] This allows a single-frequency network to be flexibly incorporated into the service area of ​​a distributed antenna system. In this way, by increasing the area of ​​the single-frequency network depending on the number of terminal devices 4 and the communication load, it is possible to conserve resources by reducing the number of operating communication devices 1. As a result, cell clustering can further reduce costs and power consumption. Furthermore, by distributing signals using the combining / distributing unit 22, the constraint on the number of antennas 3 connected due to the number of physical ports of the communication device 1 can be alleviated, thereby increasing the number of antennas 3 connected per communication device 1. This allows for efficient area expansion. As a result, it is possible to improve the flexibility and scalability of cell clustering control, such as realizing cell clustering specialized for area expansion. As described above, the base station B of the present invention can expand its communication area while reducing the amount of communication resources required at the base station B.

[0051] (Variation 1) In the configuration shown in Fig. 1 , a connection switching device 2 may be provided inside each communication device 1. Fig. 2 is a diagram showing an example configuration of a base station Ba in Variation 1 of the embodiment. The base station Ba is made up of one or more communication devices 1a. As shown in Fig. 2, each communication device 1a includes a communication control unit 110, a transmission unit 120, a signal processing unit 130, a beam control unit 140, and a communication unit 150, as well as a connection switching device 2. As a result, each communication device 1a may switch connections between each antenna 3 and multiple data communication cards or communication infrastructures related to communication resources (cell resources) inside the device.

[0052] (Variation 2) The communication device 1 does not need to include the beam control unit 140. When configured in this manner, the signal processing unit 130 outputs the modulated data signal or the switching control signal to the communication unit 150. The signal processing unit 130 performs demodulation processing on the data signal input from the communication unit 150, for example. The communication unit 150 transmits the data signal output from the signal processing unit 130 to each antenna 3 via the connection switching device 2. The communication unit 150 transmits the data signal input from the connection switching device 2 to the signal processing unit 130.

[0053] (Modification 3) In the above example, the connection switching device 2 is provided inside the base station B. In contrast, the connection switching device 2 may be provided outside the base station B and connected to one or more base stations B. Fig. 3 is a diagram showing an example of the configuration of a communication system 200 in Modification 3 of the embodiment. The communication system 200 is a system that performs wireless communication, and is, for example, a distributed antenna system.

[0054] The communication system 200 includes a plurality of communication devices 1, a connection switching device 2, Y antennas 3, and X terminal devices 4. The plurality of communication devices 1 constitute a base station Bb. In FIG. 3, the communication devices 1 constituting the base station Bb are two communication devices 1-1 to 1-2, but the number of communication devices 1 is not particularly limited. As shown in FIG. 3, the connection switching device 2 is connected to each communication device 1 included in the base station Bb as an external device of the base station Bb. In FIG. 3, the connection switching device 2 is connected to one base station Bb, but the connection switching device 2 may be connected to a plurality of base stations Bb. The processing in the communication system 200 is the same as the processing described above.

[0055] (Hardware Configuration) FIG. 4 is a diagram illustrating an example of the hardware configuration of the communication device 1 according to an embodiment. The communication device 1 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 150 executes predetermined communication processing.

[0056] The communication device 1 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).

[0057] For example, "base station," "radio base station," "NodeB," "eNodeB," "gNodeB," "access point," "cell," "macrocell," "small cell," "femtocell," and "picocell" can be read interchangeably.

[0058] 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.

[0059] Although an embodiment of the present invention has been described above in detail 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.

[0060] The present invention is applicable to distributed antenna systems.

[0061] REFERENCE SIGNS LIST 1, 1-1 to 1-2, 1a, 1a-1 to 1a-2...communication device, 2...connection switching device, 3, 3-1 to 3-Y...antenna, 4, 4-1 to 4-X...terminal device, 21, 23...switching unit, 22, 22-1 to 22-2...combining and dividing unit, 100, 200...communication system, 110...communication control unit, 120...transmission unit, 130...signal processing unit, 140...beam control unit, 150...communication unit, B, Ba, Bb...base station

Claims

1. A base station comprising: one or more communication devices each having communication resources for each cell and forming one or more cells using a plurality of antennas arranged in a dispersed manner; a plurality of switching units that switch the connection relationship between the communication resources of the one or more communication devices and the plurality of antennas; and one or more combining / distributing units that combine or distribute input signals between the plurality of switching units.

2. The base station according to claim 1, wherein the plurality of switching units are a first switching unit and a second switching unit, the one or more combining / distributing units are provided on a portion of the communication path connecting the first switching unit and the second switching unit, and the first switching unit outputs the signal to the second switching unit via the one or more combining / distributing units or directly to the second switching unit depending on the input signal.

3. The base station according to claim 1 or 2, wherein the plurality of switching units and the one or more combining / distributing units are provided in the one or more communication devices.

4. A connection switching device connected to one or more base stations, comprising: a communication device provided at the one or more base stations, the communication resources provided by the one or more communication devices that form one or more cells using a plurality of antennas that are distributed and have communication resources for each cell; a plurality of switching units that switch the connection relationship with the plurality of antennas; and one or more combining / distributing units that combine or distribute input signals between the plurality of switching units.

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