JP2023133768A - Wireless communication system, unit rearrangement method therefor, and program - Google Patents

Abstract

To improve communication quality, such as throughput or delay time, by controlling a position of a base station device (unit) or a direction of radio waves.SOLUTION: In RU, a position acquisition unit 101 identifies its own position, and notifies a RAN controller of it together with a direction of radio waves. A direction control unit 102 controls the direction of the radio waves. In DU, a position acquisition unit 201 identifies its own position, and notifies the RAN controller of it. A traffic increase detection unit 202 detects a sign of traffic increase and notifies the RAN controller of it. In the RAN controller, a rearrangement calculation unit 301 calculates rearrangement of the RU, the DU, and antennas so that traffic with tendency of increase is dispersed to other radio base stations. A rearrangement unit 302 rearranges positions of the RU and the DU and the direction of the radio waves of the RU on the basis of a result of calculating the rearrangement.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless communication system and its unit relocation method and program, and particularly to wireless communication that improves communication quality such as throughput and delay time by controlling the position of a base station device (unit) and the direction of radio waves. The present invention relates to a system and its unit relocation method and program.

With the advancement of fifth-generation wireless communication systems (5G), it is expected that the demand for high-capacity, low-latency, and multi-connection communications will further increase compared to when it was first introduced. Additionally, as 5G is widely used in a wide variety of services such as robot control, connected cars, and AR/VR, it is becoming increasingly important to simultaneously satisfy the quality requirements of each service.

In order to meet the quality demands of diversified services, Non-Patent Document 1 proposes that a radio access network (RAN) consisting of a large number of base stations is divided into multiple logical networks (slices) and divided according to the service. RAN slicing technology has been proposed to flexibly customize slices.

On the other hand, Massive MIMO technology that simultaneously allocates resources to multiple terminals in the same direction by directing a narrow beam from a base station antenna in a specific direction is disclosed in Non-Patent Document 2.

In addition, the conventionally integrated base station functions are divided into a CU (Centralized Unit) that performs session processing, a distributed unit (DU) that performs baseband processing, and an RU (Radio Unit) that performs radio processing. The O-RAN Alliance is currently working on specifications to open up the interface specifications between each unit. The O-RAN Alliance is also considering specifications for a RAN controller (RIC: RAN Intelligent Controller) for integrated RAN control.

Furthermore, it is expected that each function of a base station will become more compact, and as robot and drone technology advances, the mobility of each function will increase. In Patent Document 1, a technique for avoiding communication congestion using a movable Wi-Fi AP is considered for the purpose of offloading traffic in a wireless communication system.

Japanese Patent Application Publication No. 2018-11156

Shunliang Zhang, "An Overview of Network Slicing for 5G," IEEE Wireless Communications, pp. 111-117, April 2019. Erik G. Larsson et al., "Massive MIMO for next generation wireless systems," IEEE Communications Magazine, pp. 186-195, Feb. 2014.

Conventionally, in order to improve the communication quality of wireless communication systems, technologies such as dividing the network for each service and dividing the space by generating narrow beams using Massive MIMO technology have been considered. However, since it does not control the physical location of the base station, it is difficult to deal with local traffic congestion.

On the other hand, technology is also being considered that uses mobile Wi-Fi APs to offload traffic in areas where it is congested. However, since the Wi-Fi AP is a separate system from the wireless communication system, there is a problem that integrated control cannot be performed.

The purpose of the present invention is to solve the above technical problems and provide a wireless communication system that can improve communication quality such as throughput and delay time by controlling the position of a base station device (unit) and the direction of radio waves. The purpose of the present invention is to provide a unit relocation method and program.

In order to achieve the above object, the present invention controls a plurality of radio base stations by a RAN controller, and each radio base station has at least one of a session unit (CU), a distributed unit (DU), and a radio unit (RU). A wireless communication system including one unit and having an open interface between each unit is characterized by having the following configuration.

(1) A means for notifying the RAN controller of the location of each RU, a means for detecting a radio base station whose traffic is increasing and notifying the RAN controller, and a means for distributing the increasing traffic to other radio base stations. The RAN controller is provided with means for calculating the relocation of each RU so that the RAN controller can relocate each RU, and means for relocating each RU based on the calculation result of the relocation.

(2) Further comprising means for notifying the RAN controller of the direction of radio waves for each RU to communicate with the wireless terminal, and the means for calculating the relocation further calculates the relocation of the direction of the radio waves of each RU. I did it like that.

(3) The system further includes means for notifying the RAN controller of positional information of DUs connected to each RU, and the means for calculating relocation further calculates relocation of each DU.

(1) Since it becomes possible to relocate RUs of other wireless base stations near the RU of a wireless base station whose traffic is increasing, it is possible to distributively process local increases in traffic using multiple RUs. It becomes possible. Therefore, even when wireless terminals are locally concentrated and traffic density temporarily becomes extremely high, communication quality such as throughput and delay time can be improved.

(2) In addition to the location of the RU, the direction of the radio waves is also optimized by relocation, so by directing more radio waves in the direction where there are more wireless terminals, communication quality such as throughput and delay time can be further improved. I can do it.

(3) Since the position of the DU connected to the relocated RU can also be relocated, the range in which RUs can be relocated can be expanded.

FIG. 1 is a functional block diagram showing the configuration of main parts of a radio access network (RAN) to which the present invention is applied. This is a sequence flow showing a procedure in which a distributed unit DU and a wireless unit RU notify a RAN controller of information regarding their own position and direction of radio waves. This is a sequence flow showing a procedure for detecting a local increase in traffic and dynamically rearranging the positions of the distributed unit DU and wireless unit RU and the direction of radio waves using the antenna ANT of the wireless unit RU. 12 is a flowchart showing a procedure in which the RAN controller calculates the positions of the distributed unit DU and the wireless unit RU, and the relocation of the radio wave direction of the wireless unit RU. FIG. 6 is a diagram showing an example of calculation of relocation of the position of the wireless unit RU and the direction of radio waves.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a functional block diagram showing the configuration of the main parts of a radio access network (RAN) to which the present invention is applied, and components unnecessary for explanation of the present invention are omitted here. In the present invention, the interfaces between the session unit CU, distributed unit DU, and radio unit RU of each radio base station are made common and open according to specifications compliant with the O-RAN Alliance.

The radio access network RAN accommodates a plurality of radio base stations, each base station including at least one of a session unit CU, a distribution unit DU and a radio unit RU. Base station A includes all of CU, DU and RU, base station B1, C1 includes CU and DU, base station D1 includes CU, base station D2 includes DU, base station B2, C1, C2, D3 contains RU.

Each CU of base stations A, B1, C1, and D1 is connected to core network CN via backhaul. The CU of each base station is connected to the DU of the same base station or other corresponding base stations by midhaul. The DU of each base station is fronthaul connected to the RU of the same base station or other corresponding base stations.

The CU and DU of each base station are connected to the RAN controller via a control signal interface, and can control slices, bandwidth, Massive MIMO, etc. The RAN controller and DU exchange information about the current location and the direction of radio waves for communicating with wireless terminals through the control signal interface and the RU connected to each DU through the fronthaul.

The radio access network RAN periodically acquires information regarding the location of each DU, the location of each RU, and the direction of radio waves for communicating with wireless terminals, and further detects local increases in traffic. Then, the positions of the DUs and RUs and the directions of the radio waves of the RUs are rearranged based on the information regarding the positions and the directions of the radio waves so that locally increased traffic is distributed to other radio base stations.

Each RU is mounted on a mobile V _RU such as a vehicle, robot, or drone, and can be moved to a designated relocation position. The DU is mounted on a mobile V _DU and can be moved to a designated relocation position. Each of the mobile bodies V _RU and V _DU moves the mounted DU and RU to the relocation position based on the calculation result of the relocation. Each RU rearranges the direction of radio waves for communicating with a wireless terminal using the antenna ANT, based on the calculation result of the rearrangement.

In addition to the functions of a general RU, each RU includes a position acquisition unit 101 that measures its current position using an appropriate system such as GPS, and a direction control unit 102 that controls the direction of radio waves. In addition to the functions provided by a general DU, the DU has a position acquisition unit 201 that measures its current position using an appropriate system such as GPS, and a traffic increase detection unit 202 that detects an excessive increase in the number of connected terminals or traffic. Equipped with

The RAN controller includes a relocation calculation section 301 and a relocation section 302 in addition to the functions of a general RAN controller. The relocation calculation unit 301 rearranges the DUs and RUs based on the information regarding the positions of the DUs and RUs and the direction of radio waves of each RU so that traffic increased at some base stations is distributed to other base stations. Calculate the relocation of the position and direction of the radio waves. The relocation unit 302 instructs each mobile body V DU and V _RU carrying the DU and _RU to move the DU and RU based on the calculation result of the relocation, and further instructs the direction control unit 102 of the RU to move the DU and RU. Change the direction of radio waves.

FIG. 2 is a sequence flow showing a procedure in which the distributed unit DU and the radio unit RU notify the RAN controller of information regarding their own location and radio wave direction, and is repeatedly executed at a predetermined period.

The RU acquires its current position P _RU in the position acquisition unit 101, acquires the current direction D _ANT in which each antenna ANT points in the direction control unit 102, and transmits it to the DU at time t1. If the RU supports Massive MIMO, obtain the beam direction as the radio wave direction D _ANT .

The DU acquires its current position P _DU in the position acquisition unit 201, and transmits it to the RAN controller at time t2, along with the position P _Ru and the radio wave direction D _ANT acquired from the RU. The RAN controller updates and registers the received position P _RU , P _DU and radio wave direction D _ANT information.

Figure 3 shows the procedure for detecting a local increase in the number of connected terminals or wireless traffic, and dynamically relocating the positions of the distributed unit DU and wireless unit RU, as well as the radio wave direction of the wireless unit RU, using the antenna ANT. This is the sequence flow.

When the traffic increase detection unit 202 of a certain distributed unit DU (DU _T ) detects an increasing trend in the number of wireless terminals MN connected to that wireless unit RU or the amount of wireless traffic, the traffic increase detection unit 202 of a certain distributed unit DU (DU _T ) detects an increasing trend in the number of wireless terminals MN connected to that wireless unit RU or the amount of wireless traffic. Traffic increase information is sent to the RAN controller via the control signal interface.

This traffic increase information describes an ID unique to the distributed unit _DUT and the amount of traffic. The RAN controller calculates the position of each distributed unit DU and radio unit RU and the relocation with respect to the radio direction of each RU in response to receiving the traffic augmentation information.

FIG. 4 is a flowchart showing a procedure in which the RAN controller calculates relocation. In step S1, the distributed unit DU _T that transmitted the traffic increase information is based on the location information of the RU that is periodically updated and registered. The location of the wireless unit _RUT connected to is obtained.

In step S2, the top N wireless units RU that are close to the wireless unit RU _T are selected as candidates for relocation. In step S3, relocation targets are narrowed down to the top n (n≦N) wireless units RUs with the most free resource capacity from among the N wireless units RUs. In step S4, a relocation calculation is performed for distributing and arranging the narrowed down n wireless units RU in the vicinity of the wireless unit RU _T.

In this embodiment, the n RUs are rearranged so that a large number of wireless terminals MN connected to the wireless unit RU _T can be handed off to the n RUs after the rearrangement at a rate according to their free capacity. The position is calculated. In step S5, a direction is calculated for rearranging the radio waves of the n wireless units RU after the rearrangement so that they are directed more toward the direction where there are more wireless terminals MN.

FIG. 5 is a diagram showing an example of calculating the relocation of a wireless unit RU and its antenna ANT. When base stations 50-57 all include wireless units RU and an increase in traffic is detected at base station 50, It shows.

First, the top five RUs (base stations 51-56) that are close to the base station 50 are selected as candidates for relocation. Relocation targets are narrowed down to the top four base stations 51-55 with the highest capacity. Then, the positions to relocate the narrowed-down four base stations 51-55 are calculated, and furthermore, the direction in which the radio waves of each wireless unit RU are to be relocated is calculated.

Returning to FIG. 4, in step S6, it is determined whether relocation is necessary for each distributed unit DU connected to the n wireless units RU after the relocation. In this embodiment, a distributed unit DU whose distance from the wireless unit RU after relocation exceeds a predetermined threshold is determined to require relocation, and the process proceeds to step S7, where the position to relocate the distributed unit DU is calculated. .

In the present embodiment, an appropriate position where the distances from the connected wireless unit RU and the session processing unit CU are both equal to or less than a predetermined threshold is calculated as the position where the distributed unit DU is to be relocated.

Returning to FIG. 3, at time t12, the calculation result of the relocation is transmitted to the corresponding distributed unit DU via the control signal interface. If the objects to be relocated are the distributed unit DU, the wireless unit RU, and its antenna ANT, the position where the distributed unit DU is to be relocated, the position where the wireless unit RU is to be relocated, and the direction in which the radio waves are to be relocated are transmitted.

When the distributed unit DU receives the relocation calculation result, it extracts the position where the connected wireless unit RU is to be relocated and the direction in which its radio waves are to be relocated, and at time t13, it sends a fronthaul to the wireless unit RU. Send via. Furthermore, if the relocation calculation result includes the position where the distributed unit DU is to be relocated, it instructs its own mobile device V _DU to move to the relocation position.

When the radio unit RU receives the relocation calculation result from the distributed unit DU, it instructs its own mobile unit VR _U to move to the relocation position, and also instructs the direction control unit 102 in the direction of the radio waves. Relocate.

According to this embodiment, RUs of other wireless base stations can be relocated near the RU of a wireless base station whose traffic is increasing, so local increases in traffic can be distributed among multiple RUs. This makes it possible to improve communication quality such as throughput and delay time.

In addition, according to this embodiment, in addition to the RU, the direction and beam direction of the antenna ANT are also optimized by rearranging, so that by directing more radio waves in the direction where there are many wireless terminals, throughput, delay time, etc. communication quality can be further improved.

Furthermore, according to this embodiment, the position of the DU connected to the relocated RU can also be relocated, so the range in which RUs can be relocated can be expanded.

According to the above-described embodiment, it is possible to improve communication quality such as throughput and delay time of wireless communication, so it is possible to provide a variety of communication and entertainment to many people regardless of geographical or economic disparity. be able to provide it. As a result, Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, ``Build resilient infrastructure and promote inclusive and sustainable industrialization,'' and Goal 11, ``Make cities inclusive, safe and resilient.'' It will be possible to contribute to "making the world more sustainable and more sustainable."

101...Position acquisition unit, 102...Direction control unit, 201...Position acquisition unit, 202...Traffic increase detection unit, 301...Relocation calculation unit, 302...Relocation unit

Claims (13)

Multiple wireless base stations are controlled by a RAN controller, each wireless base station includes at least one of a session unit (CU), a distributed unit (DU), and a radio unit (RU), and the interface between each unit is open. In wireless communication systems,
means for notifying the RAN controller of the location of each RU;
means for detecting a wireless base station whose traffic is increasing and notifying a RAN controller;
means for calculating relocation of each RU in the RAN controller so that the increasing traffic is distributed to other radio base stations;
A wireless communication system comprising: means for rearranging each RU based on the calculation result of the rearrangement. 2. The means for calculating relocation calculates relocation so that other RUs are distributed in the vicinity of an RU connected to a wireless base station whose traffic tends to increase. wireless communication system. 3. The wireless communication system according to claim 1, wherein the relocation means moves the first mobile body carrying the RU to a position according to the calculation result of the relocation. Further comprising means for notifying the RAN controller of the direction of radio waves for each RU to communicate with the wireless terminal,
4. The wireless communication system according to claim 1, wherein the means for calculating the relocation further calculates the relocation of the radio wave direction of each RU to be relocated. further comprising means for notifying the RAN controller of the location information of each DU,
5. The wireless communication system according to claim 1, wherein the means for calculating the relocation further calculates the relocation of a DU connected to the RU to be relocated. 6. The wireless communication system according to claim 5, wherein the means for calculating the relocation calculates the relocation of each DU based on the position of the CU to which each DU is connected and the position of the RU after the relocation. system. 7. The wireless communication system according to claim 5, wherein the relocation means moves the second mobile body carrying the DU to a position according to the calculation result of the relocation. Multiple wireless base stations are controlled by a RAN controller, each wireless base station includes at least one of a session unit (CU), a distributed unit (DU), and a radio unit (RU), and the interface between each unit is open. In the unit relocation method of a wireless communication system,
Notify the RAN controller of the location of each RU,
Detects wireless base stations whose traffic is increasing and notifies the RAN controller.
calculating relocation of each RU in the RAN controller so that the increasing traffic is distributed to other radio base stations;
A unit relocation method for a wireless communication system, characterized in that each RU is relocated based on the calculation result of the relocation. Each RU notifies the RAN controller of the direction of radio waves for communicating with wireless terminals,
When calculating the relocation, further calculate the relocation of the radio wave direction of each RU to be relocated,
9. The method of relocating units in a wireless communication system according to claim 8, further comprising rearranging the direction of radio waves. Notify the location information of each DU to the RAN controller,
When calculating the relocation, further calculating the relocation of the DU connected to the RU to be relocated,
10. The unit relocation method for a wireless communication system according to claim 8 or 9, characterized in that the position of each DU is relocated. Multiple wireless base stations are controlled by a RAN controller, each wireless base station includes at least one of a session unit (CU), a distributed unit (DU), and a radio unit (RU), and the interface between each unit is open. In the wireless communication system unit relocation program,
The procedure for notifying the RAN controller of the location of each RU,
A procedure for detecting a wireless base station whose traffic is increasing and notifying the RAN controller;
calculating relocation of each RU in a RAN controller so that the increasing traffic is distributed to other radio base stations;
A unit relocation program for a wireless communication system, characterized in that the program causes a computer to execute a procedure for relocating each RU based on the calculation result of the relocation. further including a procedure for notifying the RAN controller of the direction of radio waves for each RU to communicate with the wireless terminal;
In the step of calculating the relocation, further calculating the relocation of the radio wave direction of each RU to be relocated,
12. The unit relocation program for a wireless communication system according to claim 11, wherein the program relocates a direction of a radio wave. further comprising a step of notifying the RAN controller of the location information of each DU,
In the step of calculating the relocation, further calculating the relocation of the DU connected to the RU to be relocated,
The unit relocation program for a wireless communication system according to claim 11 or 12, characterized in that the program relocates the position of each DU.

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