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

Abstract

A wireless communication system according to one embodiment is a wireless communication system in which a wireless terminal enabled to perform multilink transmission and a base station perform wireless communication, the wireless communication system comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be subjected to multilink transmission between the wireless terminal and the base station; a calculation unit that calculates, on the basis of the communication quality information, a minimum capacity expected to be required for each link; a selection unit that selects, for each link, a channel position and bandwidth as a candidate settable to satisfy the calculated minimum capacity; an evaluation unit that evaluates communication quality for each link when a signal is transmitted by each selected candidate of a channel position and bandwidth; and a determination unit that determines a channel position and bandwidth for each link when the difference between the evaluation results of links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

Description

Wireless Communication System, Communication Control Device, Wireless Communication Method, and Communication Control Program

[0001] The present invention relates to a wireless communication system, a communication control device, a wireless communication method, and a communication control program.

[0002] For example, in the IEEE 802.be standard, multi-link transmission (Multi-Link Operation: MLO) that performs frame transmission by utilizing a plurality of transmission paths (links) with different frequency channels is planned to be defined.

[0003] A wireless device that performs MLO mounts a plurality of different wireless interfaces in one housing, establishes a plurality of transmission paths, and is called a multi-link device (MLD) (see, for example, Non-Patent Document 1).

[0004] Also, in MLO, it is possible to transmit a packet with one TID (Traffic-ID) through a plurality of links, and an increase in communication capacity can be expected.

[0005] "IEEE P802.11beTM / D5.0", Draft Standard for Information technology - Telecommunications and information exchange between systems Local and metropolitan area networks - Specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 8: Enhancements for extremely high throughput (EHT), Prepared by the 802.11 Working Group of the LAN / MAN Standards Committee of the IEEE Computer Society, November 2023

[0006] In MLO, links are assigned to multiple frequency channels for each TID. However, if the communication quality varies among the assigned frequency channels, and channels with poor communication quality are mixed in, the overall delay jitter of the link may increase.

[0007] Furthermore, if the order of packets differs significantly across multiple links, packet loss can occur at higher layers due to buffering issues, leading to a deterioration in service quality. In particular, streaming services such as video and audio can experience data loss, directly resulting in video and audio distortion.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a wireless communication system, a communication control device, a wireless communication method, and a communication control program that enable multilink transmission while maintaining communication quality and increasing transmission capacity.

[0009] A wireless communication system according to one embodiment of the present invention is a wireless communication system in which a wireless terminal capable of multilink transmission and a base station capable of multilink transmission perform wireless communication, and is characterized by comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit that calculates the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit that selects candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit that evaluates the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit; and a determination unit that determines the channel positions and bandwidths for each of the links when the difference between the results evaluated by the evaluation unit for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

[0010] Furthermore, a communication control device according to one embodiment of the present invention is a communication control device that controls wireless communication between a wireless terminal capable of multilink transmission and a base station capable of multilink transmission, and is characterized by comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit that calculates the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit that selects candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit that evaluates the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit; and a determination unit that determines the channel positions and bandwidths for each of the links when the difference between the results evaluated by the evaluation unit for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

[0011] Furthermore, a wireless communication method according to one embodiment of the present invention is a wireless communication method in which a wireless terminal capable of multilink transmission and a base station capable of multilink transmission perform wireless communication, and is characterized by including an acquisition step of acquiring communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation step of calculating the minimum capacity expected to be required for each of the links based on the communication quality information acquired in the acquisition step; a selection step of selecting candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated in the calculation step; an evaluation step of evaluating the communication quality when a signal is transmitted using each of the candidate channel positions and bandwidths selected in the selection step for each of the links; and a determination step of determining the channel positions and bandwidths for each of the links when the difference between the results evaluated in the evaluation step for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

[0012] Furthermore, a communication control program according to one embodiment of the present invention is a communication control program executed by a communication control device that controls wireless communication between a wireless terminal capable of multilink transmission and a base station capable of multilink transmission, and is a communication control program for causing a computer to function as each part of the communication control device, comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit that calculates the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit that selects candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit that evaluates the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit; and a determination unit that determines the channel positions and bandwidths for each of the links when the difference between the results evaluated by the evaluation unit for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

[0013] According to the present invention, it becomes possible to perform multilink transmission while maintaining communication quality and increasing transmission capacity.

[0014] This figure shows an example configuration and overview of a wireless communication system according to one embodiment. This figure shows an overview of a wireless terminal and base station according to one embodiment, and an example of multilink transmission performed by the wireless terminal and base station. This figure illustrates packet data transmission of a comparative example using each of the first to third links. This figure illustrates the functions of a base station according to one embodiment. This figure illustrates a method by which the evaluation unit evaluates communication quality using RTT. This figure illustrates a method by which the evaluation unit evaluates communication quality using standby time. This flowchart shows an example of operation of a wireless communication system according to one embodiment. This figure shows an example of hardware configuration of a base station (or communication control device) according to one embodiment.

[0015] A wireless communication system according to one embodiment will be described below with reference to the drawings. Figure 1 is a diagram showing an example of the configuration and overview of a wireless communication system 10 according to one embodiment.

[0016] As shown in Figure 1, in one embodiment of the wireless communication system 10, for example, a plurality of wireless terminals (Non-AP MLDs) 20, each capable of multilink transmission, perform wireless communication with a base station (AP-MLD) 30, which is also capable of multilink transmission.

[0017] Furthermore, the wireless communication system 10 includes a communication control device 40, a Wi-Fi® sniffer 42, and a network monitoring service 44. The wireless communication system 10 collects and analyzes quality information for each channel that can be set in each link (frequency channel band) of multilink transmission performed between each of the multiple wireless terminals 20 and the base station 30, and performs multilink transmission while maintaining communication quality and increasing transmission capacity.

[0018] For example, the base station 30 may acquire connection information and channel scan information that it can verify using its NIC (Network Interface Card).

[0019] Furthermore, the Wi-Fi sniffer 42 may be, for example, a Wi-Fi terminal operating in sniffer mode, and may perform packet capture to observe the packet flow of each channel and the transmission status of the base station 30 to be controlled over a predetermined period of time.

[0020] Furthermore, the wireless communication system 10 may utilize information (such as the busy rate) obtained from the base station 30 by using a Wi-Fi controller service provided by the monitoring service 44.

[0021] The base station 30 then collects information from each of the above-mentioned information sources and, for example, uses the results of analysis by its own communication control program (analysis program) to determine the channel setting.

[0022] Furthermore, the communication control device 40 (or monitoring service 44) may collect information from each of the above-mentioned information sources and determine the channel setting using, for example, the results of analysis performed by its own communication control program (analysis program).

[0023] Figure 2 shows an overview of a wireless terminal 20 and a base station 30 according to one embodiment, and an example of multilink transmission performed by the wireless terminal 20 and the base station 30.

[0024] The wireless terminal (STA MLD) 20 includes, for example, a first STA (Non-AP STA) 210 using the 2.4 GHz band, a second STA 220 using the 5 GHz band, and a third STA 230 using the 6 GHz band. The base station (AP MLD) 30 includes, for example, a first AP 310 using the 2.4 GHz band, a second AP 320 using the 5 GHz band, and a third AP 330 using the 6 GHz band.

[0025] The wireless terminal 20 and base station 30 perform multilink transmission by forming a first link with the first STA 210 and the first AP 310, a second link with the second STA 220 and the second AP 320, and a third link with the third STA 230 and the third AP 330.

[0026] At this time, the wireless terminal 20 and the base station 30 transmit packet data for each TID using each of the first to third links. Each of the first to third links can independently select and configure a channel. When the wireless terminal 20 and the base station 30 can obtain the necessary communication capacity using each of the first to third links, they configure the channel position and bandwidth so that the quality on each channel is uniformly maintained at or above a predetermined value.

[0027] For example, the wireless communication system 10 selects a combination of channel setting candidates that maximizes capacity from among the candidate channel setting candidates selected on the condition that each link maintains a quality of a predetermined value or higher.

[0028] Figure 3 illustrates packet data transmission in a comparative example using each of the first to third links. As shown in Figure 3, in packet data transmission in a comparative example using each of the first to third links, there can be significant differences in communication quality between links.

[0029] In the example shown in Figure 3, a packet with a single TID is transmitted through multiple links. For example, on the first link, the channel bandwidth is narrow, resulting in high latency. On the second link, there is a lot of interference, leading to frequent packet retransmissions and transmission waiting states. On the third link, there is less interference and sufficient transmission capacity. When there are such large differences in communication capacity and quality between links, the overall latency jitter of the links can increase.

[0030] Therefore, the wireless communication system 10 according to one embodiment is configured to enable multilink transmission by increasing transmission capacity while maintaining the overall communication quality of the links, even when a packet with a single TID is transmitted through multiple links.

[0031] Figure 4 illustrates the functions of a base station 30 according to one embodiment. As shown in Figure 4, the base station 30 has an acquisition unit 31, a calculation unit 32, a selection unit 33, an evaluation unit 34, and a determination unit 35. Note that Figure 4 does not show the basic functions of a base station that are generally present in the base station 30.

[0032] The acquisition unit 31 acquires communication quality information indicating the communication quality of the signal to be transmitted via multilink between the wireless terminal 20 and the base station 30, and outputs the acquired communication quality information to the calculation unit 32.

[0033] The calculation unit 32 calculates the minimum capacity expected to be required for each link based on the communication quality information acquired by the acquisition unit 31, and outputs the calculated minimum capacity to the selection unit 33.

[0034] The selection unit 33 selects candidate channel positions and bandwidths for each link that can be set to satisfy the minimum capacities calculated by the calculation unit 32, and outputs the selection results to the evaluation unit 34.

[0035] The selection unit 33 divides the frequency band so that each link does not interfere with one another, and selects candidate channels that are set to channels that are separated by a certain value or more. The selection unit 33 then selects channel settings (channel position, bandwidth, (primary channel) or settable channel number) that satisfy predetermined requirements for channel capacity as candidate channel settings. For bandwidths where there are no candidate channels, the selection unit 33 may choose not to use that bandwidth as the selection result.

[0036] The evaluation unit 34 evaluates the communication quality for each link when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit 33, and outputs the evaluation results to the determination unit 35. The results evaluated by the evaluation unit 34 are, for example, quantified wireless quality conditions such as delay values.

[0037] For example, the evaluation unit 34 may use the delay time required for packet arrival in the Upper MAC between transmission and reception between the wireless terminal 20 and the base station 30 as an indicator for evaluating communication quality. Alternatively, the evaluation unit 34 may evaluate communication quality using other easily observable indicators. For example, the evaluation unit 34 may evaluate communication quality using RTT (Round-Trip Time) or waiting time.

[0038] Figure 5 illustrates a method by which the evaluation unit 34 evaluates communication quality using RTT.

[0039] For example, the evaluation unit 34 may evaluate the communication quality using the time from the start of transmission to the completion of normal reception, which is measured at the wireless terminal 20 targeted by an observation device such as a packet capture device.

[0040] In this case, the evaluation unit 34 checks the capture result set in which the transmitting address and receiving address are those of the target wireless terminal 20, and confirms the sequence number of the packet. The evaluation unit 34 then takes the difference between the transmission start time of the sequence number and the reception completion time of the ACK frame after successful reception as the RTT. The evaluation unit 34 may also obtain a statistical mean or median as the analysis value by increasing the number of samples checked.

[0041] Further, the evaluation unit 34 may estimate the time from the start of transmission to the completion of normal reception using the MCS, retransmission rate, etc., and evaluate the communication quality.

[0042] In this case, the evaluation unit 34 estimates the MCS of an individual from the received power value, and calculates the frame time length using a typical frame size. Then, the evaluation unit 34 may calculate the time until a frame is normally received using the retransmission rate and the MAC overhead, and acquire it as the RTT.

[0043] FIG. 6 is a diagram illustrating a method in which the evaluation unit 34 evaluates communication quality using the waiting time.

[0044] For example, the evaluation unit 34 may estimate the channel busy rate using the number of interfering terminals for each frequency channel. For example, the evaluation unit 34 uses the number of interfering terminals as the number of wireless terminals 20 connected to the surrounding base stations 30 or the wireless terminals 20 whose channel is to be set. Then, the evaluation unit 34 uses, for example, the analysis method of the waiting time with respect to the number of interfering terminals shown in the following Document A.

[0045] Document A: Oliver, Miquel, and Ana Escudero. "Study of different CSMA / CA IEEE 802.11-based implementations." EUNICE contribution (1999).

[0046] Further, the evaluation unit 34 may estimate the waiting time using the busy rate measured by a direct observation device (not shown). For example, when the busy rate is the occupancy time rate of the transmission frames on the channel with respect to the previous time, the probability of accessing the channel during the available time is (channel vacancy rate = 100% - channel busy rate).

[0047] For a simple calculation, the evaluation unit 34 may calculate the waiting time = [access right acquisition time in CSMA / CA access during available time] + (channel busy rate / channel vacancy rate) × [channel busy time]. Then, the evaluation unit 34 may use, for example, the analysis method shown in the following Document B.

[0048] Document B: G. Bianchi, "Performance analysis of the IEEE 802.11 distributed coordination function," in IEEE Journal on Selected Areas in Communications, vol. 18, no. 3, pp. 535-547, March 2000, doi: 10.1109 / 49.840210.

[0049] Then, the evaluation unit 34 may measure the response time when a load such as Ping is applied, or estimate the response time by adding the above-mentioned waiting time.

[0050] The determination unit 35 (FIG. 4) selects an optimal combination from the candidate groups of channel settings that are candidates for each link. Here, the optimal combination is, for example, a combination in which the total capacity is maximized and the difference in the communication quality evaluation of each link is within a predetermined range.

[0051] Specifically, the determination unit 35 determines the position and bandwidth of each channel of each link when the difference between the results evaluated by the evaluation unit 34 for each link is within a predetermined range and the multi-link transmission capacity between the wireless terminal 20 and the base station 30 is maximized.

[0052] Note that each function shown in FIG. 4 is not limited to being possessed by the base station 30, and may be provided in, for example, the communication control device 40.

[0053] Next, an operation example of the wireless communication system 10 according to an embodiment will be described. FIG. 7 is a flowchart showing an operation example of the wireless communication system 10 according to an embodiment.

[0054] In step 100 (S100), the base station 30 (or the communication control device 40, etc.) acquires information necessary for calculating each link capacity.

[0055] In step 102 (S102), the base station 30 (or the communication control device 40, etc.) calculates the required capacity for each link.

[0056] In step 104 (S104), the base station 30 (or communication control device 40, etc.) selects candidate channel locations and bandwidths that satisfy the capacity of each link.

[0057] In step 106 (S106), the base station 30 (or communication control device 40, etc.) evaluates the quality of each channel candidate.

[0058] In step 108 (S108), the base station 30 (or communication control device 40, etc.) determines a combination of channels in which the differences in the quality evaluation results of each link fall within a predetermined range and the total capacity of each link is maximized.

[0059] Thus, the wireless communication system 10 according to one embodiment determines the channel position and bandwidth of each link when the difference in the results of evaluating the communication quality of each link falls within a predetermined range and the multilink transmission capacity between the wireless terminal 20 and the base station 30 is maximized. Therefore, it is possible to perform multilink transmission with increased transmission capacity while maintaining communication quality.

[0060] Furthermore, the functions of the wireless terminal 20, base station 30, and communication control device 40 may be partially or entirely comprised of hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or they may be comprised of programs executed by a processor such as a CPU.

[0061] For example, the base station 30 and the communication control device 40 can each be implemented using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0062] Figure 8 shows an example of the hardware configuration of a base station 30 (or communication control device 40) according to one embodiment. As shown in Figure 8, for example, the base station 30 has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and is equipped with computer functions. The base station 30 is also configured to input and output data to and from a computer-readable storage medium 57.

[0063] The input unit 50 is, for example, a keyboard and mouse. The output unit 51 is, for example, a display device such as a display that outputs images. The communication unit 52 is, for example, a wired and wireless network interface, and may also have the function of an output unit that outputs data to the outside.

[0064] The CPU 53 controls each component of the base station 30 and performs predetermined processing. The memory 54 and HDD 55 are storage units that store data, etc.

[0065] The storage medium 57 is capable of storing programs and the like that cause the base station 30 to execute its functions. Note that the architecture of the base station 30 is not limited to the example shown in Figure 8.

[0066] The functions realized by the components described herein may be implemented in a circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (a Central Processing Unit), conventional circuits, and / or combinations thereof, programmed to realize the functions described herein.

[0067] A processor includes transistors and other circuits and is considered circuitry or processing circuitry. A processor may also be a programmed processor that executes programs stored in memory.

[0068] In this specification, circuitry, unit, and means are hardware programmed to perform or execute the functions described herein. Such hardware may be any hardware disclosed herein, or any hardware known to be programmed to perform or execute the functions described herein.

[0069] If the hardware is a processor that is considered to be a type of circuitry, then the circuitry, means, or unit is a combination of hardware and software used to constitute the hardware and / or processor.

[0070] 10... Wireless communication system, 20... Wireless terminal, 30... Base station, 31... Acquisition unit, 32... Calculation unit, 33... Selection unit, 34... Evaluation unit, 35... Determination unit, 40... Communication control device, 42... Wi-Fi sniffer, 44... Monitoring service, 50... Input unit, 51... Output unit, 52... Communication unit, 53... CPU, 54... Memory, 55... HDD, 56... Bus, 57... Storage medium, 210... 1st STA, 220... 2nd STA, 230... 3rd STA, 310... 1st AP, 320... 2nd AP, 330... 3rd AP

Claims

1. A wireless communication system in which a wireless terminal capable of multilink transmission and a base station capable of multilink transmission perform wireless communication, comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit that calculates the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit that selects candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit that evaluates the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit; and a determination unit that determines the channel positions and bandwidths for each of the links such that the difference between the results evaluated by the evaluation unit for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

2. A communication control device for controlling wireless communication between a wireless terminal capable of multilink transmission and a base station capable of multilink transmission, comprising: an acquisition unit for acquiring communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit for calculating the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit for selecting candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit for evaluating the communication quality when a signal is transmitted using the candidate channel positions and bandwidths selected by the selection unit for each of the links; and a determination unit for determining the channel positions and bandwidths for each of the links when the difference between the evaluation results for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

3. A wireless communication method in which a wireless terminal capable of multilink transmission and a base station capable of multilink transmission perform wireless communication, comprising: an acquisition step of acquiring communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation step of calculating the minimum capacity expected to be required for each of the links based on the communication quality information acquired in the acquisition step; a selection step of selecting candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated in the calculation step; an evaluation step of evaluating the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected in the selection step; and a determination step of determining the channel positions and bandwidths for each of the links such that the difference between the results evaluated in the evaluation step for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized.

4. A communication control program executed by a communication control device that controls wireless communication between a wireless terminal capable of multilink transmission and a base station capable of multilink transmission, comprising: an acquisition unit that acquires communication quality information indicating the communication quality of a signal to be transmitted via multilink between the wireless terminal and the base station; a calculation unit that calculates the minimum capacity expected to be required for each of the links based on the communication quality information acquired by the acquisition unit; a selection unit that selects candidate channel positions and bandwidths for each of the links that can be set to satisfy the minimum capacities calculated by the calculation unit; an evaluation unit that evaluates the communication quality for each of the links when a signal is transmitted using each of the candidate channel positions and bandwidths selected by the selection unit; and a determination unit that determines the channel positions and bandwidths for each of the links when the difference between the results evaluated by the evaluation unit for each of the links falls within a predetermined range and the multilink transmission capacity between the wireless terminal and the base station is maximized; and a computer functioning as each part of the communication control device.

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