WO2024013815A1

WO2024013815A1 - Wireless communication system, wireless communication method, centralized control device, and centralized control program

Info

Publication number: WO2024013815A1
Application number: PCT/JP2022/027292
Authority: WO
Inventors: 純一岩谷; ヒランタアベセカラ; 裕介淺井; 朗岸田; 花絵大谷; 信也大槻; 陸大宮; 泰司鷹取
Original assignee: 日本電信電話株式会社
Priority date: 2022-07-11
Filing date: 2022-07-11
Publication date: 2024-01-18

Abstract

A wireless communication system according to one embodiment is characterized by comprising a centralized control device that performs centralized control of a plurality of base stations, including a base station capable of performing multilink transmission with wireless terminals. Said system is also characterized by the centralized control device including: a utility function calculation unit that, for each wireless device, calculates, as a utility function, a ratio of a traffic volume transmittable with an allocated channel and bandwidth to an accommodation traffic volume; a multiplication unit that respectively multiplies each utility function calculated by the utility function calculation unit by a coefficient that positively correlates with a priority level predetermined for each wireless device; and a change control unit that performs control for changing the channel and the bandwidth of each wireless device so as to maximize the total of the utility functions each of which has been multiplied by the coefficient by the multiplication unit.

Description

Wireless communication system, wireless communication method, central control device and central control program

The present invention relates to a wireless communication system, a wireless communication method, a centralized control device, and a centralized control program.

For example, in IEEE802.11 (wireless LAN), a single device is equipped with multiple different wireless LAN interfaces and has a function of establishing multiple transmission paths, and such a device is called a multilink device (MLD). It is called.

Multilink transmission (multilink function) includes, for example, an AP MLD equipped with multiple base station (AP: Access Point) functions in one housing, and multiple wireless terminals (STA: Station) installed in one housing. This is wireless communication in which a link is formed between each STA and MLD.

Therefore, in multi-link transmission, it is possible to improve the reliability of data reception by transmitting the same data in parallel, or to improve the transmission efficiency by transmitting different data.

Additionally, RATOP (Resource allocation based on Area Throughput Optimization Policy) is known as a method for centrally controlling the frequency bandwidth and channels used by wireless LAN APs to maximize the effective throughput of the entire system. For example, see Non-Patent Document 1).

In RATOP, a centralized control device grasps the status of each AP and allocates radio resources such as frequency channels and bandwidths that each AP should use.

For example, in RATOP, as an evaluation index for radio resource allocation, the amount of traffic that can be sent out based on the allocated radio resources (channel/bandwidth) is calculated based on the estimated maximum traffic amount (accommodated traffic amount) of each AP. The ratio (utility function) of the estimated amount (traffic amount that can be sent) is defined. Then, the central control device performs control to maximize the total value of the utility functions.

The present invention provides a wireless communication system, a wireless communication method, and a wireless communication method capable of centrally controlling the allocation of wireless resources so as to expand communication capacity according to priority for a system including a base station capable of multi-link transmission. The purpose is to provide a centralized control device and a centralized control program.

A wireless communication system according to an embodiment of the present invention includes a base station capable of multi-link transmission with a wireless terminal, and includes a plurality of base stations capable of communicating with the wireless terminal for each wireless device accommodated, and the base station. In a wireless communication system comprising a central control device that centrally controls each station, the central control device determines, for each of the wireless devices, the ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the allocated channel and bandwidth. a utility function calculation unit that calculates the function as a function; and a multiplication unit that multiplies each of the utility functions calculated by the utility function calculation unit by a coefficient that has a positive correlation with a predetermined priority for each wireless device; The wireless device is characterized by comprising a change control unit that performs control to change the channel and bandwidth of each of the wireless devices so that the sum of the utility functions after being multiplied by the respective coefficients by the multiplication units is maximized.

Furthermore, the wireless communication method according to an embodiment of the present invention includes a base station that is capable of multi-link transmission with a wireless terminal, and each wireless device that accommodates a plurality of base stations that can communicate with the wireless terminal. In the centrally controlled wireless communication method, a utility function calculating step of calculating, as a utility function, a ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the allocated channel and bandwidth for each of the wireless devices, and each of the calculated utility functions. , a multiplication step of multiplying each wireless device by a coefficient having a positive correlation with a predetermined priority, and a multiplication step of multiplying each wireless device by a coefficient having a positive correlation with a predetermined priority, and a multiplication step of multiplying the wireless The method is characterized in that it includes a change control step of controlling to change the channel and bandwidth of each device.

Further, the centralized control device according to an embodiment of the present invention includes a base station capable of multi-link transmission with wireless terminals, and each wireless device accommodated has a plurality of base stations capable of communicating with the wireless terminal. In the centralized control device that performs centralized control, a utility function calculation unit that calculates, as a utility function, a ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the assigned channel and bandwidth for each of the wireless devices; and the utility function calculation unit a multiplier that multiplies each of the utility functions calculated by a coefficient that has a positive correlation with a predetermined priority for each wireless device; and a multiplier that multiplies each of the utility functions calculated by the coefficients. The present invention is characterized by comprising a change control unit that performs control to change the channel and bandwidth of each of the wireless devices so as to maximize the total.

According to the present invention, it is possible to centrally control radio resource allocation for a system including a base station capable of multi-link transmission so as to expand communication capacity according to priority.

1 is a diagram illustrating a configuration example of a wireless communication system according to an embodiment. FIG. 2 is a functional block diagram illustrating functions of the central control device. FIG. 2 is a diagram schematically illustrating a utility function U calculated by the central control device for a plurality of base stations capable of multi-link transmission and a plurality of base stations that do not perform multi-link transmission. 4 is a diagram schematically showing wireless devices of each base station shown in FIG. 3. FIG. 1 is a flowchart illustrating an example of the operation of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating a hardware configuration of a central control device according to an embodiment. 1 is a diagram illustrating a configuration example of a wireless communication system that does not include a multilink device. FIG. 3 is a diagram showing a specific example of a RATOP algorithm executed by the central control device.

First, the background of the invention will be explained. FIG. 7 is a diagram illustrating a configuration example of a wireless communication system 1 that does not include a multilink device. The wireless communication system 1 is, for example, a wireless LAN system that does not include AP MLD and STA MLD, and the above-mentioned RATOP is applied.

As shown in FIG. 7, the wireless communication system 1 includes, for example, a plurality of base stations 2, a central control device 3, and a plurality of wireless terminals 4 connected to a network 100. Each base station 2 accommodates a plurality of wireless terminals 4 by being centrally controlled by a central control device 3 . Hereinafter, a base station may be referred to as an AP.

The centralized control device 3 performs RATOP control for a plurality of base stations 2. At this time, it is assumed that the control index is the utility function U (=corresponding to satisfaction level) shown in equation (1) below.

a: AP identifier b: Bandwidth c: Channel (primary channel)
R: Data rate (MCS)

The expected throughput of AP (a) depends on the channel usage status of other APs. Further, the accommodated traffic amount (depending on the amount of generated data) is, for example, the estimated maximum traffic value of AP (a) shown in the following equation (2).

Then, the centralized control device 3 performs processing to maximize the sum ΣU of the utility functions U according to the following algorithm.

RATOP algorithm:
(A): The central control device 3 "tentatively allocates" the channel/bandwidth used by each AP according to predetermined rules.
(B): The centralized control device 3 calculates the sum ΣU of the utility functions U of each AP in the above case (A).
(C): The centralized control device 3 reallocates channels and bandwidths to APs with a low utility function U, and performs control so that ΣU does not decrease. Then, the centralized control device 3 repeats the step (C) within a range of predetermined conditions.

FIG. 8 is a diagram showing a specific example of the RATOP algorithm executed by the central control device 3. As shown in FIG. 8, the central control device 3 performs phase I (initial calculation) and phase II (optimization) processing.

In Phase I, the central control device 3 selects one AP and sets it as AP-a (S100), selects a bandwidth b that can be allocated to AP-a (S102), and selects a bandwidth b that can be allocated to AP-a. Channel c is selected (S104), and utility function U of AP-a is calculated (S106).

Then, the centralized control device 3 executes the process of S104 and the process of S106 for all channels c, and repeats the process for all bandwidths b.

Next, the centralized control device 3 selects the combination (b, c) that maximizes the utility function U (S108), and repeats the process for all APs.

In phase II, the centralized control device 3 selects, for example, an AP with a small utility function U, and then selects the combination (parameters) of (b, c) in which the utility function U becomes maximum and the sum ΣU of the utility functions U does not deteriorate. The process of selecting is repeated (S110).

Then, the centralized control device 3 sets the combinations (b, c) selected by each AP as the allocated bandwidth and channel after control.

Next, a wireless communication system 10 according to an embodiment will be described. FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 10 according to an embodiment. The wireless communication system 10 is a wireless LAN system including an AP MLD and a STA MLD, and the above-mentioned RATOP is applied to the MLD.

As shown in FIG. 1, the wireless communication system 10 includes, for example, base stations 20-1, 20-2, and 30 connected to a network 100, a central control device 40, and a plurality of

wireless terminals

50 and 52. Note that when one of the plurality of configurations, such as base stations 20-1 and 20-2, is not specified, it is simply abbreviated as base station 20 or the like.

Each of the base stations 20-1, 20-2, and 30 accommodates a plurality of

wireless terminals

50 and 52 by being centrally controlled by the central control device 40. Hereinafter, the base stations 20-1, 20-2, and 30 may be described as APs.

The wireless terminals 50 are STA and MLD, respectively. Each of the wireless terminals 52 is a terminal that does not have a multilink function.

The base stations 20-1 and 20-2 are each AP MLD, and have an MLD section 200 and

wireless devices

202 and 204.

The MLD unit 200 transmits and receives signals to and from the central control device 40 and the

wireless devices

202 and 204, and performs processing for the base station 20 to function as an AP MLD using the

wireless devices

202 and 204.

The wireless device 202 has a function as a base station (AP) that performs wireless communication using, for example, a 5 GHz band. The wireless device 204 has a function as a base station (AP) that performs wireless communication using, for example, a 6 GHz band.

The base station 30 has one wireless device 300 and does not have a multilink function. The wireless device 300 has a function as a base station (AP) that performs wireless communication using, for example, a 5 GHz band.

The centralized control device 40 centrally controls the base stations 20-1, 20-2, and 30 by, for example, wireless communication.

FIG. 2 is a functional block diagram illustrating the functions of the central control device 40. As shown in FIG. 2, the centralized control device 40 includes, for example, a wireless communication section 41, a collection section 42, a utility function calculation section 43, a multiplication section 44, a change control section 45, and a main control section 46.

The wireless communication unit 41 transmits and receives signals to and from the base stations 20-1, 20-2, and 30 by wireless communication, respectively.

The collection unit 42 collects information regarding the base stations 20-1, 20-2, and 30 via the wireless communication unit 41, and outputs the information to the utility function calculation unit 43. For example, the collection unit 42 collects information (traffic information, etc.) regarding each of the

wireless devices

202, 204, and 300.

Based on the information collected by the collection unit 42, the utility function calculation unit 43 calculates, as a utility function, the ratio of the amount of traffic that can be sent to the amount of traffic that can be accommodated based on the allocated channel and bandwidth for each of the

wireless devices

202, 204, and 300. and outputs the calculated utility function to the multiplier 44.

The accommodated traffic amount (data generation amount) depends on the traffic distribution ratio to each of the

wireless devices

202, 204, and 300. For example, based on the information collected by the collection unit 42, the utility function calculation unit 43 calculates the amount of accommodated traffic so as to distribute it in proportion to the amount of traffic that can be sent, the amount of accommodated traffic, or the bandwidth of each of the

wireless devices

202, 204, and 300, for example. Assume quantity.

The multiplication unit 44 multiplies each of the utility functions calculated by the utility function calculation unit 43 by a coefficient that has a positive correlation with the priority determined in advance for each of the

wireless devices

202, 204, and 300. Then, the multiplication unit 44 outputs the utility functions multiplied by the respective coefficients to the change control unit 45.

Note that the coefficient multiplied by the multiplication unit 44 is determined in advance in order to maintain the priorities and fairness of each of the

wireless devices

202, 204, and 300. For example, a coefficient having a larger value is determined for a wireless device with a high priority than a wireless device with a low priority.

The change control unit 45 performs control to change the channels and bandwidths of each of the

wireless devices

202, 204, and 300 so that the sum of the utility functions after multiplication by the coefficients by the multiplication unit 44 is maximized.

In addition, the change control unit 45 selects the wireless devices in order from the wireless devices with the smallest utility function or the wireless devices of the base station with the smallest sum of the utility functions after the multiplication unit 44 multiplies the wireless devices in the base station by the coefficient. control to change the channels and bandwidth allocated to Furthermore, in order to give priority to the control order of a base station with a high priority, wireless devices within the base station may be multiplied by different small coefficients to compare the magnitude of the utility function between base stations.

Further, the change control unit 45 changes the channel and bandwidth allocated to each wireless device in order from the wireless device with the highest priority indicated by the coefficient or the base station with the largest sum of the coefficients of each of the wireless devices it accommodates. Control may also be performed.

The main control section 46 controls each section that constitutes the central control device 40.

In other words, the centralized control device 40 multiplies the utility function calculated for each wireless device by a coefficient corresponding to the priority of each wireless device, and controls the allocation of wireless resources based on the utility function after multiplying by the coefficient. I do.

FIG. 3 is a diagram schematically illustrating a utility function U calculated by the central control device 40 for a plurality of base stations capable of multi-link transmission (AP MLD) and a plurality of base stations that do not perform multi-link transmission. be. Further, FIG. 4 is a diagram schematically showing wireless devices of each base station shown in FIG. 3.

Here, a plurality of base stations capable of multi-link transmission (AP MLD) are referred to as base stations 20-1 and 20-2, and a plurality of base stations that do not perform multi-link transmission (single base station) are referred to as base stations 30-1 and 20-2. The score shall be 30-2. Furthermore, base stations 20-1 and 20-2 each include

wireless devices

202 and 204. It is also assumed that the base stations 30-1 and 30-2 are equipped with either a wireless device that uses a 5 GHz band or a 6 GHz band.

In FIG. 3, Ai indicates the amount of accommodated traffic, and Bi indicates the amount of traffic that can be sent out (i is a variable). In other words, the utility function Ui=Bi/Ai. Moreover, ai is a predetermined coefficient.

Then, the centralized control device 40 performs control so as to maximize the sum of the utility function U after being multiplied by the coefficient shown in equation (3) below.

Further, the centralized control device 40 may determine the wireless device whose parameters are to be controlled based on the utility function U for each of the base stations 20-1, 20-2, 30-1, and 30-2. For example, the centralized control device 40 may first control parameters for wireless devices or base stations with a small utility function U (for example, a1U1+a2U2, etc.) for each base station after multiplication by a coefficient, and then control parameters for each wireless device or base station. Control may be performed to ensure fairness. In addition, in order to prioritize the control order of base stations with high priority, wireless devices within the base station are multiplied by different small coefficients (for example, b1, b2) to compare the magnitude of the utility function between base stations. You can.

Furthermore, the centralized control device 40 may control the parameters in the order of wireless devices with a high priority (wireless devices with a large predetermined coefficient), or in the order based on the value of the utility function U after multiplying by the coefficient. Parameters of the wireless device may also be controlled.

Next, an example of the overall operation of the wireless communication system 10 will be described. FIG. 5 is a flowchart illustrating an example of the operation of the wireless communication system 10 according to an embodiment.

First, each of the base stations 20-1, 20-2, and 30 determines whether or not there is an instruction to collect information from the central control device 40 (S200), and if there is an instruction (S200: Yes), the base stations 20-1, 20-2, and 30 If there is no instruction (S200: No), the process of S200 is repeated.

In step 202 (S202), the base stations 20-1, 20-2, and 30 transmit the traffic status and the like of the

wireless devices

202, 204, and 300 that they accommodate to the central control device 40.

In step 204 (S204), the base stations 20-1, 20-2, and 30 issue a control instruction (or It is determined whether there is a control instruction (to update the traffic distribution) from the central control device 40. When the base stations 20-1, 20-2, and 30 determine that there is a control instruction (S204: Yes), the process proceeds to S206, and when it is determined that there is no control instruction (S204: No), the process proceeds to S200. Return to processing.

In step 206 (S206), the base stations 20-1, 20-2, and 30 perform change control to change the bandwidth b and channel c (parameters) (or control to update the traffic allocation).

In this way, the wireless communication system 10 according to one embodiment controls the allocation of wireless resources based on the utility function multiplied by a coefficient according to the priority, and therefore includes a base station capable of multi-link transmission. Wireless resource allocation can be centrally controlled for the system so as to expand communication capacity according to priority.

Note that each function of the central control device 40 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or may be executed by a processor such as a CPU. It may also be configured as a program.

For example, the central control device 40 can be realized using a computer and a program, and the program can be recorded on a storage medium or provided through a network.

FIG. 6 is a diagram illustrating the hardware configuration of the central control device 40 according to one embodiment. As shown in FIG. 6, the centralized control device 40 has an input section 400, an output section 410, a communication section 420, a CPU 430, a memory 440, and an HDD 450 connected to each other via a bus 460, and has a function as a computer. The central control device 40 is also capable of inputting and outputting data to and from a computer-readable storage medium 470.

The input unit 400 is, for example, a keyboard and a mouse. The output unit 410 is, for example, a display device such as a display.

The communication unit 420 is a communication interface that performs wireless communication using, for example, a wireless LAN.

The CPU 430 controls each part of the central control device 40 and performs predetermined processing. The memory 440 and HDD 450 store data and the like.

The storage medium 470 is capable of storing programs and the like that execute the functions of the central control device 40. Note that the architecture configuring the centralized control device 40 is not limited to the example shown in FIG.

DESCRIPTION OF SYMBOLS 10... Wireless communication system, 20-1, 20-2, 30... Base station, 40... Central control device, 41... Wireless communication unit, 42... Collection unit, 43... Utility function calculation unit, 44... Multiplication unit, 45... Change control unit, 46... Main control unit, 50, 52... Wireless terminal, 100... Network, 200... MLD unit, 202, 204, 300... Wireless device, 400... Input unit, 410... Output unit, 420... Communication unit, 430... CPU, 440... Memory, 450... HDD, 460...Bus, 470...Storage medium

Claims

A wireless device including a base station capable of multi-link transmission with a wireless terminal, a plurality of base stations capable of communicating with the wireless terminal for each wireless device accommodated, and a central control device that centrally controls each of the base stations. In communication systems,
The central control device includes:
a utility function calculation unit that calculates, as a utility function, a ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the allocated channel and bandwidth for each of the wireless devices;
a multiplication unit that multiplies each of the utility functions calculated by the utility function calculation unit by a coefficient that has a positive correlation with a predetermined priority for each wireless device;
a change control unit that performs control to change the channel and bandwidth of each of the wireless devices so as to maximize the sum of the utility functions after each of the multiplication units multiplies the coefficients. Communications system.
The change control unit includes:
Channels to be assigned to the wireless devices in order from the wireless device having a smaller utility function after being multiplied by the coefficient by the multiplier, or the base station having a smaller total utility function after being multiplied by the coefficient by the multiplier. The wireless communication system according to claim 1, wherein control is performed to change the bandwidth and the bandwidth.
The change control unit includes:
The base station has a small sum of utility functions after multiplying the wireless device in the base station with a high priority by a small coefficient different from the coefficient, the wireless device with a high priority indicated by the coefficient, or accommodates The wireless communication system according to claim 1, wherein control is performed to change the channel and bandwidth allocated to each of the wireless devices in order from the base station having a larger sum of the coefficients of each of the wireless devices.
In a wireless communication method that includes a base station capable of multi-link transmission with a wireless terminal and centrally controls each of a plurality of base stations capable of communicating with the wireless terminal for each wireless device accommodated,
a utility function calculation step of calculating, as a utility function, a ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the allocated channel and bandwidth for each of the wireless devices;
a multiplication step of multiplying each of the calculated utility functions by a coefficient that has a positive correlation with a predetermined priority for each wireless device;
a change control step of controlling to change the channel and bandwidth of each of the wireless devices so as to maximize the sum of the utility functions after being multiplied by the respective coefficients.
In a centralized control device that includes a base station capable of multi-link transmission with a wireless terminal and centrally controls each of a plurality of base stations that can communicate with the wireless terminal for each wireless device it accommodates,
a utility function calculation unit that calculates, as a utility function, a ratio of the amount of traffic that can be transmitted to the amount of traffic that can be accommodated based on the allocated channel and bandwidth for each of the wireless devices;
a multiplication unit that multiplies each of the utility functions calculated by the utility function calculation unit by a coefficient that has a positive correlation with a predetermined priority for each wireless device;
and a change control unit that performs control to change the channel and bandwidth of each of the wireless devices so as to maximize the sum of the utility functions after each of the multiplication units multiplies the coefficients. Control device.
The change control unit includes:
The wireless device in the base station with a high priority is multiplied by a small coefficient different from the coefficient, and then the base station has a small sum of utility functions, the wireless device has a small utility function, or the multiplication unit multiplies the coefficient The centralized control device according to claim 5, wherein control is performed to change the channel and bandwidth allocated to the wireless device in order from the base station with the smallest sum of utility functions after multiplication by .
The change control unit includes:
Control is performed to change the channel and bandwidth allocated to each of the wireless devices in order from the wireless device having a higher priority indicated by the coefficient or the base station having a larger sum of the coefficients of each of the wireless devices accommodated. The centralized control device according to claim 5, characterized in that:
A central control program for causing a computer to function as each part of the central control device according to any one of claims 5 to 7.