Wireless communication system and communication control program

Abstract

A wireless communication system (1) comprises: a server (3) that is connected to a core network; a plurality of RUs (4) that are connected to the server (3) and communicate wirelessly with a UE (6); and a plurality of RISs (5) that are controlled by the server (3), and can control reflection phases and change radio wave reflection directions by inclining electrical reflection wavefronts. The RISs (5) are connected to the server (3) by a communication line to which the server (3) and the RUs (4) are connected.

Description

Wireless communication system and communication control program

[0001] The present invention relates to wireless communication systems such as 5G networks.

[0002] 5G (fifth generation mobile communication system) has features such as high-speed communication, high reliability, low latency, and multiple simultaneous connections, and various new services that take advantage of these features have been proposed. 5G employs wireless communication using millimeter waves, and radio waves emitted from base station antennas may not reach areas shaded by obstructions, resulting in areas where communication is unavailable. In response to this, technology using a reconfigurable intelligent surface (RIS) has been proposed to expand the communication area. A RIS is a reflector that can change the reflection direction by controlling the reflection phase and tilting the electrical reflection wavefront. For example, Patent Document 1 and Patent Document 2 disclose wireless communication systems using a RIS.

[0003] 3 shows an example configuration of a conventional wireless communication system 91 equipped with a RIS 95. As shown in the figure, in the wireless communication system 91, a DU / CU 93 is connected to a 5GC 92, which is a core network device in a 5G core network, and an RU 94 is connected to the DU / CU 93. The 5GC 92 is also connected to a RIS controller 98 via a cloud network 97, and the operation of the RIS 95 is controlled by the RIS controller 98. A UE 96 serving as a user terminal communicates with the RU 94 via radio waves reflected by the RIS 95. As a result, the UE 96 can communicate with the RU 94 via the RIS 95 even in a situation where direct communication with the RU 94 is not possible due to a communication obstacle or the like.

[0004] Japan Special Table No. 2023-538822 Publication Japanese Special Table No. 2023-550809

[0005] As described above, RIS is used to provide a communication area in an area shaded by a communication obstacle. Therefore, in order to install and control a new RIS, a separate communication network must be installed for the installed RIS, which increases costs. Furthermore, when the Internet is used as the communication network for the RIS, it is difficult to increase communication speeds, making it difficult to perform stable real-time control.

[0006] An object of one aspect of the present invention is to realize a wireless communication system that can increase the wireless communication area and communication capacity while suppressing an increase in costs.

[0007] In order to solve the above problems, the wireless communication system of the present invention comprises a communication control device connected to a core network, a plurality of wireless units connected to the communication control device and performing wireless communication with user terminals, and a plurality of reflectors controlled by the communication control device and capable of changing the reflection direction of radio waves by controlling the reflection phase and tilting the electrical reflection wavefront, and the reflectors are connected to the communication control device by communication lines that connect the communication control device and the wireless units.

[0008] According to the above configuration, a wireless communication area can be established using both the wireless unit and the reflector, thereby increasing the wireless communication area and communication capacity. Furthermore, since the reflector is connected to the communication control device via a communication line that connects the communication control device and the wireless unit, there is no need to lay a separate communication line to connect the reflector and the communication control device. This eliminates the need to install a separate communication line to connect the reflector and the communication control device. This reduces the cost of building a communication network. Furthermore, since the communication control device and the wireless unit are connected via a communication line that enables stable, high-speed communication, stable, high-speed communication can also be performed between the reflector and the communication control device. This allows high-speed, highly reliable control of the reflector. The operations of the distributed / central unit and the wireless unit included in the communication control device may be controlled by a RAN Intelligent Controller (RIC).

[0009] According to the present invention, it is possible to increase the wireless communication area and communication capacity, suppress the increase in costs involved in building a communication network, and achieve high-speed and highly reliable control of a reflector.

[0010] It is a diagram showing an example of the configuration of a wireless communication system 1 according to the present embodiment.It is a diagram explaining the configuration of a fronthaul in more detail.It is a diagram showing an example of the configuration of a conventional wireless communication system.

[0011] Hereinafter, one embodiment of the present invention will be described in detail.

[0012] (Configuration example of wireless communication system) Fig. 1 shows a configuration example of a wireless communication system 1 according to this embodiment. As shown in the figure, the wireless communication system 1 includes a 5GC 2, a server (communication control device) 3, an RU (wireless unit) 4, and a RIS (reflector) 5. Note that the wireless communication system 1 according to this embodiment is assumed to be a 5G network, but is not limited to this and can be applied to any wireless communication network having similar functions.

[0013] The 5GC2 is a core network device that controls a core network consisting of exchanges, subscriber information management devices, etc., and performs tasks such as establishing user sessions and transferring user data.

[0014] The server 3 is a server device that constitutes a data center provided for each predetermined region, and has the functions of a virtualized DU / CU (Distributed Unit / Central Unit) 31 and an AI App 32.

[0015] The DU / CU 31 performs processing on the data link layer, MAC layer, and upper layer side of the physical layer. Specifically, the DU / CU 31 performs processing on the Packet Data Convergence Protocol (PDCP), which is a protocol that performs confidentiality, validity confirmation, order alignment, header compression, etc., the Radio Link Control (RLC), which is a protocol that performs retransmission control, etc., the Media Access Control (MAC), which is a protocol that performs scheduling related to wireless transmission and reception, data multiplexing and demultiplexing processing, and error correction processing using Hybrid Automatic Repeat reQuest (HARQ), etc., and the High PHY, which is a layer above the physical layer and performs processing such as scrambling and layer mapping.

[0016] The AI ​​App 32 is a functional block that runs an AI (Artificial Intelligence) application and intelligently controls the operations of the DU / CU 31, the RU 4, and the RIS 5. As will be described in detail later, in this embodiment, the AI ​​App 32 particularly controls the operation of the RIS 5 by AI. Although not shown, the server 3 may be provided with a RAN Intelligent Controller (RIC), which may control the operations of the DU / CU 31 and the RU 4.

[0017] The RUs 4 correspond to base stations installed at multiple locations and are devices that mainly perform PHY layer processing. The RUs 4 transmit and receive radio waves to and from UEs (User Equipment) 6, and also communicate with the server 3. The RUs 4 perform processes such as digital beamforming, inverse fast Fourier transform / fast Fourier transform, and DA converter / AD converter, and communicate with the UEs 6 via antennas.

[0018] In the above example, the functional division between the DU / CU 31 and the RU 4 conforms to Split Option 7-2x, which is a provision for dividing the O-RAN fronthaul functions. However, the present invention is not limited to this example. The DU and the CU may be separated into different functional blocks. Alternatively, the DU may be a DU to which multiple RUs 4 are connected using a fronthaul switch, instead of a CU.

[0019] The RIS (Reconfigurable Intelligent Surface) 5 is a reflector that can change the reflection direction of radio waves by controlling the reflection phase and tilting the electrical reflection wave surface. The RIS 5 is provided near the RU 4 and is connected to the server 3 via the same communication line that connects the RU 4 and the DU / CU 31.

[0020] (Fronthaul Configuration) Fig. 2 is a diagram illustrating the fronthaul configuration, i.e., the connection state of the DU / CU 31, RU 4, and RIS 5 in more detail. The RU 4 is communicatively connected to the DU / CU 31 of the server 3 by eCPRI (evolved Common Public Radio Interface) via, for example, a fiber serving as a backbone communication line between base stations. The RIS 5 is also connected to the server 3 by a communication line connecting the RU 4 and the server 3. The communication between the RU 4 and the server 3 and the communication between the RIS 5 and the server 3 are performed in parallel by wavelength division multiplexing such as CWDM (Coarse Wavelength Division Multiplexing).

[0021] The RIS 5 is controlled by the DU / CU 31 having a control function for the RIS 5, and is controlled, for example, by a functional portion in the DU / CU 31 that executes the function of a CU. Communication between the DU / CU 31 and the RIS 5 may be performed via eCPRI. The DU / CU 31 may also control the RIS 5 using AI control by the AI ​​App 32. The RIS 5 may also be directly controlled by the AI ​​App 32. In this case, communication between the DU / CU 31 and the RIS 5 may be performed via an interface other than eCPRI, or the RIS 5 may be directly controlled by the AI ​​App 32. In other words, the RIS control unit that controls the RIS 5 is configured by at least one of the DU / CU 31 and the AI ​​App 32.

[0022] The DU / CU 31 collectively controls multiple connected RISs 5. This allows the DU / CU 31 to control the directivity of the reflected beam from each RIS 5 so that optimal beam control is performed for each UE 6. For example, the DU / CU 31 may control the RIS 5 based on CSI (Channel State Information) sent from each UE 6. This controls the directivity of the reflected beam from the RIS 5 so that the communication state for each UE 6 is good, thereby enabling control to optimize communication quality in the area. Here, by performing AI control using the AI ​​App 32, traffic prediction calculations can be performed based on the communication states of all UEs 6 controlled by the DU / CU 31, thereby achieving control to optimize traffic distribution.

[0023] Furthermore, it is possible to irradiate the area with radio waves from the RIS 5 in addition to the antenna of the RU 4. This makes it possible to expand the communication area and increase communication capacity.

[0024] Furthermore, the antenna of the RU 4 may be configured using, for example, massive MIMO (multiple input multiple output), and the DU / CU 31 may perform beam control by combining this massive MIMO with the RIS 5. This enables communication over a wider range with reduced interference between multiple UEs 6, further improving the efficiency of frequency band utilization.

[0025] Furthermore, when the location where the RU 4 is installed is not suitable for introducing Massive MIMO, beam control equivalent to that of a Massive MIMO base station can be performed by reducing the number of base station antennas 41 and combining them with the RIS 5. This makes it possible to perform beam control equivalent to that of a large antenna even with a relatively small antenna, suppressing increases in installation costs and improving frequency band utilization efficiency.

[0026] Furthermore, the AI ​​App 32 may predict the direction of movement based on information about handover due to movement of each UE 6 across the coverage area of ​​the RU 4, and may control the RIS 5 based on the information about the direction of movement. This allows the reflected beam to follow the movement of the UE 6, thereby further optimizing the communication state.

[0027] Furthermore, since the RIS 5 is connected to the server 3 via a communication line that connects the RU 4 and the server 3, there is no need to lay a separate communication line to connect the RIS 5 and the server 3. This makes it possible to suppress increases in costs when constructing a communication network. Furthermore, since the RU 4 and the server 3 are connected via a communication line that allows stable, high-speed communication, such as fiber, as described above, stable, high-speed communication can also be performed between the RIS 5 and the server 3. This makes it possible to perform high-speed, highly reliable control of the RIS 5.

[0028] [Example of Implementation by Software] As described above, the DU / CU 31 and the AI ​​App 32 are configured by being installed on a general-purpose server and virtualized. The functions of the DU / CU 31 and the AI ​​App 32 (hereinafter referred to as "communication control device") are programs that cause a computer to function as the communication control device, and can be realized by a program that causes a computer to realize each control function of the communication control device.

[0029] In this case, the communication control device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and the storage device.

[0030] The program may be stored non-transitory on one or more computer-readable storage media. The storage media may or may not be included in the communication control device. In the latter case, the program may be supplied to the communication control device via any wired or wireless transmission medium.

[0031] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention.

[0032] (Summary) A wireless communication system according to aspect 1 of the present invention comprises a communication control device connected to a core network, a plurality of wireless units connected to the communication control device and performing wireless communication with user terminals, and a plurality of reflectors controlled by the communication control device and capable of changing the reflection direction of radio waves by controlling the reflection phase and tilting the electrical reflection wavefront, wherein the reflectors are connected to the communication control device by communication lines that connect the communication control device and the wireless units.

[0033] According to the above configuration, a wireless communication area can be established using both the wireless unit and the reflector, thereby increasing the wireless communication area and increasing communication capacity. Furthermore, since the reflector is connected to the communication control device via a communication line that connects the communication control device and the wireless unit, there is no need to lay a separate communication line to connect the reflector and the communication control device. This makes it possible to suppress increases in costs when building a communication network. Furthermore, since the communication control device and the wireless unit are connected via a communication line that enables stable, high-speed communication, stable, high-speed communication can also be performed between the reflector and the communication control device. This makes it possible to perform high-speed, highly reliable control of the reflector.

[0034] A wireless communication system according to aspect 2 of the present invention may be configured such that, in the above-mentioned aspect 1, the communication control device controls the operation of each of the reflectors installed at multiple locations, thereby performing beam control for each of the user terminals.

[0035] According to the above configuration, the directivity of the beam reflected by the reflector is controlled so as to improve the communication state at each user terminal, thereby enabling control to optimize the communication quality in the area.

[0036] A wireless communication system according to aspect 3 of the present invention may be configured such that, in aspect 1 or 2 above, the communication line connecting the communication control device and the wireless unit is fiber, and communication between the communication control device and the wireless unit and communication between the reflector and the communication control device is performed by wavelength division multiplexing.

[0037] According to the above configuration, stable and high-speed communication can be performed between the communication control device and the wireless unit, and between the reflector and the communication control device.

[0038] A wireless communication system according to aspect 4 of the present invention may be configured such that, in at least one of aspects 1 to 3 above, the communication control device controls the reflector based on channel state information sent from each of the user terminals.

[0039] According to the above configuration, the directivity of the beam reflected by the reflector is controlled so as to improve the communication state at each user terminal, thereby enabling control to optimize the communication quality in the area.

[0040] A wireless communication system according to aspect 5 of the present invention may be configured such that, in at least one of aspects 1 to 4 above, the communication control device is a server that executes, by software, the functions of a distributed / central unit that processes the data link layer, MAC layer, and upper layer side of the physical layer, and the function of controlling the reflector.

[0041] According to the above configuration, the functions of the distributed / central unit and the reflector control function can be realized by a general-purpose server, and each resource can be flexibly used depending on the traffic, etc., thereby realizing effective use of resources.

[0042] A communication control program according to aspect 6 of the present invention is a communication control program for causing a computer to function as a communication control device provided in the wireless communication system in aspect 5 above, and may be configured to cause the computer to realize the functions provided by the communication control device.

[0043] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0044] REFERENCE SIGNS LIST 1 Wireless communication system 2 5GC 3 Server (communication control device) 4 RU (radio unit) 5 RIS (reflector) 6 UE (user terminal) 31 DU / CU (distributed / central unit) 32 AI App

Claims

1. A wireless communication system comprising: a communication control device connected to a core network; a plurality of wireless units connected to the communication control device and performing wireless communication with user terminals; and a plurality of reflectors controlled by the communication control device and capable of changing the reflection direction of radio waves by controlling the reflection phase and tilting the electrical reflection wavefront, wherein the reflectors are connected to the communication control device by communication lines that connect the communication control device and the wireless units.

2. The wireless communication system according to claim 1, wherein the communication control device controls the operation of each of the reflectors installed at a plurality of locations, thereby controlling beams for each of the user terminals.

3. A wireless communication system as described in claim 1, wherein the communication line connecting the communication control device and the wireless unit is fiber, and communication between the communication control device and the wireless unit and communication between the reflector and the communication control device is performed by wavelength division multiplexing.

4. The wireless communication system according to claim 1, wherein said communication control device controls said reflector based on channel state information sent from each of said user terminals.

5. The wireless communication system according to claim 1, wherein the communication control device is a server that executes, by software, the functions of a distributed / central unit that processes the data link layer, MAC layer, and upper layer side of the physical layer, and the function of controlling the reflector.

6. A communication control program for causing a computer to function as a communication control device provided in the wireless communication system according to claim 5, the program causing the computer to realize the functions provided by said communication control device.

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