WO2023054252A1

WO2023054252A1 - Communication device, communication device control method, and program therefor

Info

Publication number: WO2023054252A1
Application number: PCT/JP2022/035679
Authority: WO
Inventors: 智行 ▲高▼田
Original assignee: キヤノン株式会社
Priority date: 2021-09-30
Filing date: 2022-09-26
Publication date: 2023-04-06
Also published as: JP2023051565A

Abstract

The present invention enables the provision of a communication device for executing a frame exchange sequence with a number of spatial streams that accords with the spatial stream capability of each link for which an EMLMR link is established.

Description

COMMUNICATION DEVICE, COMMUNICATION DEVICE CONTROL METHOD, AND THEREOF

The present invention relates to a communication device that performs wireless communication, a control method for the communication device, and a program therefor.

With the recent increase in the amount of data being communicated, the development of communication technologies such as wireless LAN (Local Area Network) is underway. The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as a major wireless LAN communication standard. The IEEE 802.11 standard series includes standards such as IEEE 802.11a/b/g/n/ac/ax. For example, the latest standard, IEEE802.11ax, uses OFDMA (orthogonal frequency multiple access) to achieve a high peak throughput of up to 9.6 gigabits per second (Gbps), as well as a technology that improves communication speeds under congested conditions. (see Patent Document 1). Note that OFDMA is an abbreviation for Orthogonal frequency-division multiple access.

A task group called IEEE 802.11be was launched as a successor standard aimed at further improving throughput, improving frequency utilization efficiency, and improving communication latency.

In IEEE802.11be, multi-link communication is being considered, in which one AP constructs multiple links with one STA (station) in frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz, and performs simultaneous communication. there is An AP in multi-link communication is called an AP MLD (Access point multi-link device), and an STA is called a non-AP MLD (non-Access point multi-link device).

Also, in IEEE 802.11be, enhanced multi-link multi-radio (EMLMR) operation in multi-link communication is under consideration. The non-AP MLD operating in EMLMR mode performs initial frame exchange after initial frame exchange with the number of spatial streams according to the per-link spatial stream capability for each EMLMR link. Until the end of the frame exchange sequence on the link, it operates as follows. The operation is to receive a PPDU (Physical layer convergence protocol data unit) with the number of spatial streams that maximizes the value presented in the EMLMR supported MCS AND NSS SET subfield of the Common Info field of the Basic variant Multi-Link element, and This is the operation of transmitting PPDU with the number of spatial streams indicated in the supported MCS AND NSS SET subfield.

JP 2018-50133 A

　When multiple EMLMR links are established, it has not been considered to execute the frame exchange sequence with the number of spatial streams according to the spatial stream capability for each link on which the EMLMR links are established.

An object of the present invention is to provide a communication device that executes a frame exchange sequence with the number of spatial streams according to the spatial stream capability for each link on which an EMLMR link is established.

A communication device according to the present invention is a communication device that operates as a multi-link device conforming to the IEEE802.11 series standard, and includes a first enhanced multi-link multi-radio (EMLMR) link and a second enhanced multi-radio (EMLMR) link. -link multi-radio) link, without allocating a particular link's spatial stream to said first EMLMR link and said second EMLMR link when performing a frame exchange sequence on two links; and control means for controlling execution of a frame exchange sequence with a respective number of spatial streams of the link and said second EMLMR link.

According to the present invention, it is possible to provide a communication device that executes a frame exchange sequence with the number of spatial streams according to the spatial stream capability for each link on which an EMLMR link is established.

1 is a diagram showing the configuration of a network in the present invention; FIG. 1 is a diagram showing a hardware configuration of a communication device according to the present invention; FIG. 1 is a diagram showing a functional configuration of a communication device according to the present invention; FIG. 1 is a diagram showing an overview of Multi-Link communication; FIG. FIG. 10 is a diagram showing a Basic variant Multi-Link element included in an Association Request frame; FIG. 10 is a diagram showing the EMLMR Capabilities subfield included in the Common Info field of the Basic variant Multi-Link element; Fig. 4 is a flowchart of the processing performed to initiate a frame exchange sequence on an EMLMR link in accordance with the present invention; Fig. 4 is a flowchart of the processing performed to initiate a frame exchange sequence on an EMLMR link in accordance with the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

(Configuration of wireless communication system)
FIG. 1 shows the configuration of a network searched by a communication device 101 (hereinafter referred to as Non-AP MLD 101) according to this embodiment. A communication device 102 (hereafter, AP MLD 102 ) is an access point (AP) that has a role of constructing the wireless network 100 . AP MLD 102 can communicate with Non-AP MLD 101 . This embodiment applies to Non-AP MLD 101 and AP MLD 102 .

Each of the Non-AP MLD 101 and AP MLD 102 can perform wireless communication conforming to the IEEE802.11be (EHT) standard. Note that IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. The Non-AP MLD 101 and AP MLD 102 can communicate in frequencies of 2.4 GHz band, 5 GHz band and 6 GHz band. The frequency band used by each communication device is not limited to this, and different frequency bands such as the 60 GHz band may be used. Also, the Non-AP MLD 101 and AP MLD 102 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz and 320 MHz. The bandwidth used by each communication device is not limited to this, and different bandwidths such as 240 MHz and 4 MHz may be used.

The Non-AP MLD 101 and AP MLD 102 can realize multi-user (MU, Multi User) communication by multiplexing signals of a plurality of users by executing OFDMA communication conforming to the IEEE802.11be standard. OFDMA stands for Orthogonal Frequency Division Multiple Access. In OFDMA communication, a part of the divided frequency band (RU, Resource Unit) is assigned to each STA so as not to overlap each other, and the carriers of each STA are orthogonal. Therefore, the AP can communicate with multiple STAs in parallel within the defined bandwidth.

In general, radio waves reach different ranges depending on their frequency. It is known that the lower the frequency, the greater the radio wave diffraction and the greater the reach, and the higher the frequency, the less the radio wave diffraction and the shorter the reach. Even if there are obstacles on the way, low-frequency radio waves can reach around the obstacles, but high-frequency radio waves tend to travel in a straight line, making it difficult to reach them. On the other hand, the frequency of 2.4 GHz is often used by other devices, and it is known that microwave ovens emit radio waves in the same frequency band. In this way, even if the same device emits radio waves, it is conceivable that the strength of the radio waves and the SN (Signal/Noise) ratio of the received radio waves may differ depending on the location and environment of the device.

It should be noted that the Non-AP MLD 101 and AP MLD 102 are compliant with the IEEE802.11be standard, but in addition to this, they may also be compliant with the legacy standard, which is a standard prior to the IEEE802.11be standard. Specifically, the Non-AP MLD 101 and AP MLD 102 may support at least one of the IEEE802.11a/b/g/n/ac/ax standards. In addition to the IEEE802.11 series standard, other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA may be supported. UWB is an abbreviation for Ultra Wide Band, and MBOA is an abbreviation for Multi Band OFDM Alliance. Also, NFC is an abbreviation for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, and the like. Moreover, it may correspond to a communication standard for wired communication such as a wired LAN. Specific examples of the AP MLD 102 include, but are not limited to, wireless LAN routers and personal computers (PCs).

Also, the AP MLD 102 may be an information processing device such as a wireless chip capable of executing wireless communication conforming to the IEEE802.11be standard. Specific examples of the Non-AP MLD 101 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, headsets, and the like. Also, the Non-AP MLD 101 may be an information processing device such as a wireless chip capable of executing wireless communication conforming to the IEEE802.11be standard. Each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz and 320 MHz.

Also, the Non-AP MLD 101 and AP MLD 102 establish links via a plurality of frequency channels and perform multi-link communication. The IEEE 802.11 series standards define the bandwidth of each frequency channel as 20 MHz, except for the 60 GHz band. It is defined as 2.16 GHz in the 60 GHz band. Here, the frequency channel is a frequency channel defined in the IEEE802.11 series standard, and in the IEEE802.11 series standard, a plurality of frequencies are used in each of the 2.4 GHz band, 5 GHz band, 6 GHz band, and 60 GHz band. A frequency channel is defined. A bandwidth of 40 MHz or more may be used in one frequency channel by bonding with adjacent frequency channels.

For example, the AP MLD 102 has the ability to establish a link with the Non-AP MLD 101 via the first frequency channel in the 2.4 GHz band and communicate. In parallel with this, the Non-AP MLD 101 has the ability to establish a link and communicate with the AP MLD 102 via a second frequency channel in the 5 GHz band. In this case, the Non-AP MLD 101 performs multi-link communication that maintains the second link via the second frequency channel in parallel with the link via the first frequency channel. In this way, AP MLD 102 can improve throughput in communication with Non-AP MLD 101 by establishing links with Non-AP MLD 101 via multiple frequency channels.

In multi-link communication, multiple links with different frequency bands may be established between each communication device. For example, the Non-AP MLD 101 may establish links in each of the 2.4 GHz band, 5 GHz band, and 6 GHz band. Alternatively, links may be established via a plurality of different channels included in the same frequency band. For example, a 6ch link in the 2.4 GHz band may be established as the first link, and in addition, a 1ch link in the 2.4 GHz band may be established as the second link. Links with the same frequency band and links with different frequency bands may coexist. For example, the Non-AP MLD 101 may be able to establish a 1ch link in the 2.4GHz band and a 149ch link in the 5GHz band in addition to the first 6ch link in the 2.4GHz band. By establishing multiple connections with different frequencies between the Non-AP MLD 101 and the AP, even if one band is congested, communication can be established between the Non-AP MLD 101 and the other band. Therefore, it is possible to prevent a decrease in throughput and a communication delay in communication with the Non-AP MLD 101.

　In the wireless network in Fig. 1, there is one AP MLD and one Non-AP MLD, but the number and arrangement of the AP MLD and Non-AP MLD are not limited to this. For example, in addition to the wireless network in FIG. 1, one non-AP MLD may be added. The frequency band of each link to be established at this time, the number of links, and the frequency width do not matter.

When performing multi-link communication, the AP MLD 102 and the non-AP MLD 101 transmit and receive data to and from the partner device via multiple links. Data transmission/reception may be performed on one of the links forming the multi-link.

Also, the AP MLD 102 and the Non-AP MLD 101 may be able to perform MIMO (Multiple-Input And Multiple-Output) communication. In this case, the AP MLD 102 and the Non-AP MLD 101 have multiple antennas and one transmits different signals from each antenna using the same frequency channel. The receiving side simultaneously receives all signals arriving from multiple streams using multiple antennas, separates and decodes the signals of each stream. By executing MIMO communication in this way, the AP MLD 102 and Non-AP MLD 101 can communicate more data in the same amount of time than when MIMO communication is not executed. Also, the AP MLD 102 and the Non-AP MLD 101 may perform MIMO communication on some links when performing multi-link communication.

(Configuration of AP MLD and Non-AP MLD)
FIG. 2 shows a hardware configuration example of the Non-AP MLD 101 in this embodiment. Non-AP MLD 101 has storage section 201 , control section 202 , function section 203 , input section 204 , output section 205 , communication section 206 and antenna 207 . A plurality of antennas may be provided.

The storage unit 201 is composed of one or more memories such as ROM and RAM, and stores computer programs for performing various operations described later and various information such as communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. As the storage unit 201, in addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, DVDs, etc. may be used. Also, the storage unit 201 may include a plurality of memories or the like.

The control unit 202 is composed of, for example, one or more processors such as CPU and MPU, and controls the entire Non-AP MLD 101 by executing computer programs stored in the storage unit 201 . Note that the control unit 202 may control the entire Non-AP MLD 101 through cooperation between the computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 also generates data and signals (radio frames) to be transmitted in communication with other communication devices. Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. Also, the control unit 202 may be provided with a plurality of processors such as multi-core processors, and the plurality of processors may control the entire Non-AP MLD 101 .

Also, the control unit 202 controls the function unit 203 to perform predetermined processing such as wireless communication, imaging, printing, and projection. The functional unit 203 is hardware for the Non-AP MLD 101 to execute predetermined processing.

The input unit 204 receives various operations from the user. The output unit 205 performs various outputs to the user via a monitor screen or a speaker. Here, the output from the output unit 205 may be display on a monitor screen, audio output from a speaker, vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be realized by one module like a touch panel. Also, the input unit 204 and the output unit 205 may be integrated with the Non-AP MLD 101 or may be separate.

The communication unit 206 controls wireless communication conforming to the IEEE802.11be standard. In addition to the IEEE802.11be standard, the communication unit 206 may control wireless communication conforming to other IEEE802.11 series standards, and wired communication such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202 .

Note that if the Non-AP MLD 101 supports the NFC standard, the Bluetooth standard, etc. in addition to the IEEE802.11be standard, it may control wireless communication in compliance with these communication standards. Also, if the Non-AP MLD 101 can perform wireless communication conforming to a plurality of communication standards, it may be configured to have separate communication units and antennas corresponding to each communication standard. The Non-AP MLD 101 communicates data such as image data, document data, and video data with the Non-AP MLD 101 via the communication unit 206 . The antenna 207 may be configured separately from the communication unit 206, or may be configured together with the communication unit 206 as one module.

Antenna 207 is an antenna capable of communication in the 2.4 GHz band, 5 GHz band, and 6 GHz band. Although the Non-AP MLD 101 has one antenna in this embodiment, it may have three antennas. Alternatively, different antennas may be provided for each frequency band. Also, if the Non-AP MLD 101 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

The AP MLD 102 has the same hardware configuration as the Non-AP MLD 101.

FIG. 3 shows a block diagram of the functional configuration of the Non-AP MLD 101 in this embodiment. The AP MLD 102 also has the same configuration. Here, the Non-AP MLD 101 is assumed to have a wireless LAN control section 301 . Note that the number of wireless LAN control units is not limited to one, and may be two, or three or more. Non-AP MLD 101 further has frame processing section 302 , EMLMR management section 303 , UI control section 304 and storage section 305 , and radio antenna 306 .

The wireless LAN control unit 301 includes an antenna and circuits for transmitting and receiving wireless signals to and from other wireless LAN devices, and programs for controlling them. The wireless LAN control unit 301 executes wireless LAN communication control based on frames generated by the frame processing unit 302 according to the IEEE802.11 standard series.

The frame processing unit 302 processes wireless control frames transmitted and received by the wireless LAN control unit 301 . The content of the radio control generated and analyzed by the frame processing unit 302 may be restricted by settings saved in the storage unit 305 . Also, it may be changed by user setting from the UI control unit 304 . The information of the generated frame is sent to the wireless LAN control section 301 and transmitted to the communication partner. The frame information received by the wireless LAN control unit 301 is passed to the frame processing unit 302 and analyzed.

The EMLMR management unit 303 manages and controls which links are EMLMR links. Administrative controls include establishment of EMLMR links and deletion of EMLMR links.

"Establishment of an EMLMR link" refers to the state in which an EMLMR link is specified at the time of establishing a Multi-Link or after establishing a Multi-Link. Deleting an EMLMR link refers to removing the state of a link identified as an EMLMR link.

The UI control unit 304 includes hardware related to the user interface, such as a touch panel or buttons for receiving operations on the Non-AP MLD 101 by the user (not shown) of the Non-AP MLD 101, and programs that control them. Note that the UI control unit 304 also has a function of presenting information to the user, such as displaying images or outputting audio.

The storage unit 305 is a storage device that can be composed of a ROM and a RAM that store programs and data for the Non-AP MLD 101 to operate.

Fig. 4 shows the configurations of AP MLD and Non-AP MLD that perform Multi-Link communication.

A communication device that operates with Multi-Link is called an MLD (Multi-Link Device), and one MLD has multiple STAs and APs (Access Points) linked to each Link. An MLD with AP functions is called AP MLD, and an MLD without AP functions is called Non-AP MLD.

AP1 401 and STA1 404 in FIG. 4 establish Link1 407 via the first frequency channel. Similarly, AP2 402 and STA2 405 establish Link2 408 over a second frequency channel, and AP3 403 and STA3 406 establish Link3 409 over a third frequency channel.

Here, the AP MLD and the Non-AP MLD establish connections via frequency channels in the sub-GHz, 2.4 GHz, 3.6 GHz, 4.9 and 5 GHz, 60 GHz, and 6 GHz bands. The AP MLD and Non-AP MLD maintain the connection of the second link through the second frequency channel in parallel with the connection of the first link through the first frequency channel. Also, instead of connections in different frequency bands, multiple connections may be established via different frequency channels in the same frequency band.

In addition, each of Link1, Link2, and Link3 is assigned the number of spatial streams according to the spatial stream capability (per-link spatial stream capability). Assuming that there are six antennas, each link uses two antennas. That is, the spatial stream capability of each link is "2". As will be described later, when Link1 and Link2 and/or Link3 are EMLMR links, the spatial stream capability during EMLMR operation of Link1 is "4" or "6", and Link2 and/or Link3 is "0". becomes. As a result, it becomes possible to transmit and receive each data obtained by dividing one data or a plurality of different data via Link 1 using multiple antennas at the same timing and on the same frequency so as not to interfere spatially. The number of spatial streams is determined by the EHT Capabilities element or EHT Operation element included in the frame declaring that the no-AP MLD supports EHT. Specifically, it is determined based on the value of the Supported EHT-MCS And NSS Set field or Basic EHT-MCS And NSS Set field included in the EHT Capabilities element or EHT Operation element.

Fig. 5A shows the Basic Variant Multi-Link element in the Association Request frame. FIG. 5B shows the EMLMR Capabilities subfield contained in the Common Info field of the Basic variant Multi-Link element. If the EMLMR Support field is "0", it indicates that EMLMR is not supported, and if it is "1", it indicates that EMLMR is supported. When Multi-Link communication is established, all links establish EMLMR links. The Basic variant Multi-Link element is described as being included in the Association Request frame when establishing the Multi-Link, but it may also be included in the probe request frame, probe response frame, association response frame, beacon frame, etc. good.

An EMLMR link is established by sending, receiving, or exchanging a frame containing the EMLMR Support subfield with a value of 1 on each link that configures the Multi-Link. At that time, the EMLMR link may be established only with some of the links that make up the Multi-Link by doing this with only some of the links. Also, an EMLMR link may be established over multiple links, including other links, by transmitting, receiving, or exchanging a frame containing an EMLMR Support subfield with a value of 1 over one link. In that case, the EMLMR links may be established with all the links that make up the Multi-Link, or the EMLMR links may be established with only some of the links. In order to specify the link that establishes the EMLMR link, the link that establishes the EMLMR link is specified by including information for identifying the link that establishes the EMLMR link in the frame that includes the EMLMR Support subfield with a value of 1. May be specified. As information for identifying a link, a link ID (Link Identifier), a BSSID (Basic Service Set Identifier) corresponding to the link, a TID (Traffic Identifier), and the like can be used.

The EMLMR Supported MCS And NSS Set subfield indicates the maximum number of spatial streams when transmitting and receiving PPDU during EMLMR operation. ELMMR operation of a specific link reduces the number of spatial streams assigned to links other than the EMLMR-operating link, and allows the specific link to transmit and receive PPDUs with the increased number of spatial streams.

Although an instruction was given to establish the EMLMR link when establishing the Multi-Link, the establishment of the EMLMR link may be specified in an Action frame that is transmitted after the Multi-Link is established. In that case, a frame called an EML (Enhanced Multi-Link) Operating Mode Notification frame should be prepared and instructed to establish an EMLMR link. For example, in the case of Non AP MLD, when a frame containing an EMLMR Support subfield with a value of 1 is received and an EML Operating Mode Notification frame containing an EMLMR Mode subfield with a value of 1 is transmitted, those frames are The sent and received links establish an EMLMR link. Alternatively, some or all of the other links that make up the multi-link may establish the EMLMR link. Also, in the case of AP MLD, when a frame containing an EMLMR Support subfield with a value of 1 is transmitted, and an EML Operating Mode Notification frame containing an EMLMR Mode subfield with a value of 1 is received, these frames are transmitted and received. link establishes an EMLMR link. Alternatively, some or all of the other links that make up the multi-link may establish the EMLMR link. In that case, the link that establishes the EMLMR link may be specified by including information for identifying the link that establishes the EMLMR link in the EML Operating Mode Notification frame. As information for identifying a link, a link ID (Link Identifier), a BSSID (Basic Service Set Identifier) corresponding to the link, a TID (Traffic Identifier), and the like can be used.

Although it has been explained that the Non-AP MLD takes the lead in establishing the EMLMR link, the AP MLD may instruct the establishment of the EMLMR link. In addition, the EML Operating Mode Notification frame is an Action frame that non-AP MLD transmits in order to operate in EMLMR mode. It is the frame that needs to be sent to operate in EMLMR mode after it is deleted later.

Next, the operation of the AP MLD 102 when operating in EMLMR mode and exchanging frames after establishing an EMLMR link will be described using FIGS. 6 and 7. FIG. The main movement below is the movement of the frame processing unit 302 or the ELMMR control unit 303, but the movement as a communication device is the movement of the AP MLD 102. Therefore, the following description will be made with the control unit 202 of the communication apparatus as the subject of operation. It should be noted that this movement may be executed by the non AP MLD 101.

First, the movement when transmitting the start frame will be explained using FIG. Since the frame exchange sequence starts from the timing at which the start frame is transmitted, the present invention expresses that the EMLMR link that performs the ELMMR operation continues the frame exchange sequence. In S0, the control unit 202 determines that there is data to be transmitted to the communication device that is the communication partner. Data to be transmitted includes data requested to be transmitted from an arbitrary communication device to a communication device serving as a communication partner, or data generated by the function unit 203 .

In S1, the control unit 202 determines whether or not multiple EMLMR links have been established. For example, if not only Link1 but also Link2 are established, it is determined as Yes, and if only Link1 is established, it is determined as No. A conceivable method for checking whether multiple EMLMR links have been established is to determine whether each of the multiple links has transmitted and received a frame containing an EMLMR Support subfield with a value of 1. Alternatively, there is a method for determining whether each of the multiple links has transmitted a frame containing an EMLMR Support subfield with a value of 1 and received an EML Operating Mode Notification frame containing an EMLMR Mode subfield with a value of 1. Conceivable. Alternatively, it may be confirmed whether or not a plurality of ELMMR links are established by performing the above determination on any one of the links that constitute the multi-link, instead of on each of the plurality of links.

In that case, the EMLMR Support subfield with a value of 1 and the frame containing the information for identifying the link that establishes the EMLMR link are exchanged, and the link in which the information for identifying the link in the frame sent by both sides matches If there are multiple, it may be determined that multiple ELMMR links have been established. Here, in the case of non-AP MLD, instead of the frame containing the information for identifying the link that establishes the EMLMR link and the EMLMR Support subfield, EML Operating that contains information for identifying the link that establishes the EMLMR link A Mode Notification frame may be transmitted. In the case of AP MLD, receive an EML Operating Mode Notification frame containing information for identifying the link for establishing the EMLMR link, instead of the frame containing the information for identifying the link for establishing the EMLMR link and the EMLMR Support subfield You may

If it is determined as No in S1, the process proceeds to S8. At S8, the control unit 202 transmits a start frame via the EMLMR link. The start frame of the ELMMR link is the first frame transmitted in the frame exchange sequence defined in the IEEE802.11 standard Annex G. For example, there are RTS (Request To Send) frame and MU-RTS Trigger frame. This start frame serves as an instruction to start frame exchange on the EMLMR link after the EMLMR link is established.

In S9, the control unit 202 determines whether or not a response frame has been received. The response frame of the ELMMR link is a frame transmitted as a response from the communication device that received the start frame in the frame exchange sequence defined in the IEEE802.11 standard Annex G. For example, there is a CTS (Clear To Send) frame.

At S10, the control unit 202 selects a space that maximizes the number of spatial streams presented in the EMLMR Supported MCS AND NSS SET subfield of the Common Info field of the Basic variant Multi-Link element transmitted by the non-AP MLD before the start of this flow. Start frame exchange sequence with stream number. As a result, one EMLMR link performs EMLMR operation. In S17, it is determined whether or not the frame exchange sequence has ended. The description so far has been made assuming a so-called normal ELMMR operation.

Next, the operation when it is determined as Yes in S1, that is, when multiple EMLMR links are established, will be described. In S2, based on the communication performance prediction, it is determined whether or not the condition for transmitting the start frame over a plurality of ELMMR links is met. For prediction of communication performance, a method of prediction based on the degree of congestion of the channel corresponding to each link, that is, the number of non-AP MLDs connected to the AP MLD can be considered. Also, a method of measuring the received signal strength and/or the signal-to-noise power ratio of each link and predicting the communication performance of each link is conceivable. For example, if the channel on one of Link1 and Link2 is significantly more congested than the other link, or the received signal strength is low, either Link1 or Link2 will not work as both links cannot operate well. to S8 for EMLMR operation. However, if the channels of Link1 and Link2 are similarly congested or sufficiently empty, or if the received signal strength is low or sufficiently high, no improvement in communication performance can be expected by the EMLMR operation. In order to transmit and receive data with the number of spatial streams according to the spatial stream capability of , the process proceeds to S3.

At S3, the control unit 202 transmits a start frame over a plurality of EMLMR links. However, the number of spatial streams specified at this time specifies the number of spatial streams according to the spatial stream capability of each link. That is, it is the number determined by the EHT Capabilities element or the EHT Operation element included in the frame declaring that the non-AP MLD supports EHT. Other links that have not established an EMLMR link are not links that perform a frame exchange sequence.

In S4, the control unit 202 determines whether or not a response frame has been received on at least one EMLMR link. If no response frame is received within the specified period, it is determined that the frame exchange sequence will not be executed on the ELMMR link, and the process ends. On the other hand, when a response frame is received, the process proceeds to S5. In S5, the control unit 202 determines whether or not there are a plurality of EMLMR links that have received the response frame. When S5 is determined as No, the process proceeds to S10. If the determination in S5 is Yes, the process proceeds to S6. In S6, the control unit 202 performs frame exchange with the number of spatial streams according to the spatial stream capability of each link on the EMLMR link that received the response frame. In S7, it is determined whether or not the frame exchange sequence has ended, and if the determination is Yes, the process ends.

Next, the operation when receiving the start frame will be explained using FIG. In the numbering in FIG. 7, the steps overlapping with the numbering in FIG. 6 have already been explained in FIG. 6, so the explanation will be omitted. In S11, this flow is executed after the control unit 202 receives the start frame on the ELMMR link. In S12, the control unit 202 determines whether or not another start frame has been received on an EMLMR link other than the selected EMLMR link during the period from the start of reception of the start frame to the start of transmission of the response frame. to detect If determined as No in S12, the process proceeds to S18. At S18, the control unit 202 transmits a response frame to the received start frame. The rest is as described with reference to FIG.

If it is determined as Yes in S12, the process proceeds to S13. In S13, based on the prediction of communication performance, it is determined whether or not conditions for transmitting response frames over a plurality of EMLMR links are met. As with S2, a method of predicting communication performance based on the degree of congestion of the channel corresponding to each link, that is, the number of non-AP MLDs connected to the AP MLD, can be considered. Also, a method of measuring the received signal strength and/or the signal-to-noise power ratio of each link and predicting the communication performance of each link is conceivable.

If it is determined as No in S13, the process proceeds to S16. In S16, the control unit 202 selects one EMLMR link from the EMLMR links that have transmitted or received the start frame based on a predetermined criterion. EMLMR operations are performed on the selected EMLMR link. The determination method based on the predetermined criteria is the following determination method. There are roughly three determination methods: (1) selection based on information for identifying the link (link ID, etc.), (2) selection based on the order in which the EMLMR links were established, and (3) communication performance. (the degree of congestion of the channel corresponding to the link (the number of STAs connected to the AP), etc.).

When making a selection based on information for identifying a link (link ID, etc.), refer to the Link ID subfield of the Multi-Link element shown in FIG. 5A. Link ID is an ID assigned to each link by establishing Multi-Link. When IDs are assigned in the order in which link IDs are established, the link with the lowest link ID number among the multiple EMLMR links is selected as one EMLMR link. Alternatively, a link with a higher link ID number may be selected as one EMLMR link.

If the selection is based on the order in which the ELMMR links were established, more specifically, the selection is based on at least one of the following orders.
- The order in which frames containing the EMLMR Support subfield with a value of 1 were transmitted - The order in which frames containing the EMLMR Support subfield with a value of 1 were received - The frames containing the EMLMR Support subfield with a value of 1 were transmitted and The order in which the EML Operating Mode Notification frames containing the EMLMR Mode subfield with a value of 1 were sent (for non-AP MLD)
- The order in which EML Operating Mode Notification frames containing the EMLMR Mode subfield with a value of 1 are received (in the case of AP MLD)
- The order in which a frame containing an EMLMR Support subfield with a value of 1 is received and an EML Operating Mode Notification frame containing an EMLMR Mode subfield with a value of 1 is transmitted (in the case of non-AP MLD)
- The order in which a frame containing an EMLMR Support subfield with a value of 1 is transmitted and an EML Operating Mode Notification frame containing an EMLMR Mode subfield with a value of 1 is received (in the case of AP MLD)

If the frame contains information for identifying a link that establishes an EMLMR link, the EMLMR link identified by that information may be selected based on the order in which the information is transmitted or received. Also, the EMLMR link identified by the information may be selected based on the order in which the transmitted information for identifying the link establishing the EMLMR link matches the received information.

An order is assigned to each EMLMR link starting with a value of 1 according to this order. That is, the EMLMR link with the link order of 1 is the EMLMR link selected according to the predetermined criteria. For example, if the EMLMR links are selected in the order in which the frames containing the EMLMR Support subfield with a value of 1 are received, the AP MLD receives the frame containing the EMLMR Support subfield with a value of 1 on Link1, and then on Link2. , Link1 is assigned the order of 1, so Link1 is selected. As described in other embodiments, when selecting a plurality of EMLMR links, the links are selected in descending order of order up to a prescribed value that allows the EMLMR links to be established.

When selecting based on communication performance, the degree of congestion of the channel corresponding to each EMLMR link is measured, and the EMLMR link with the lowest degree of congestion is selected as one EMLMR link. As a measuring method, there is a method of judging by the number of STAs connected to the AP, and a method of obtaining the channel occupancy rate in each link of the Multi-Link can be considered.

If it is determined as Yes in S13, the process proceeds to S14. In S14, the control unit 202 transmits response frames through the plurality of EMLMR links from which the start frame was received, and transitions to S15. In S15, the control unit 202 executes frame exchange with the number of spatial streams according to the spatial stream capability of each link on the EMLMR link that transmitted the response frame. In S7, it is determined whether or not the frame exchange sequence has ended, and if the determination is Yes, the process ends.

As described above, in the first embodiment, the method of properly controlling the operation in the EMLMR mode when a plurality of start frames are exchanged with the communication device of the other party before the start of the EMLMR operation has been described. A specific method for proper control is a control method for exchanging frames on one EMLMR link or on a plurality of EMLMR links depending on whether or not to exchange frame exchange sequences on a plurality of EMLMR links. Continue the frame exchange sequence on the selected EMLMR link, and if there is an unselected EMLMR link, temporarily stop the frame exchange sequence on that EMLMR link.

[Other Examples]
In the first embodiment, it is determined in S5 of FIG. 6 whether or not there are a plurality of EMLMR links that have received the response frame, and depending on the result, the process transitions to either step S6 or S10. However, S5 may be skipped. In this case, it is determined in S4 whether a response frame has been received on at least one ELMMR link, and if the result is Yes, the process proceeds to step S6.

Although the method of selecting one EMLMR link is disclosed in the first embodiment, a plurality of EMLMR links may be operated in EMLMR mode. For example, assume that four links, Link1 to Link4, are formed between a communication device and a communication device on the other end. When Link1 and Link2 are operated as an EMLMR link, there is a method of allocating the spatial stream of Link3 to Link1 and the spatial stream of Link4 to Link2. As a result, the number of spatial streams of Link1 and Link2 increases, while the number of spatial streams of Link3 and Link4 decreases. Since such a case is conceivable, when a plurality of EMLMR links that increase the number of spatial streams can exist, a plurality of EMLMR links can be selected based on a predetermined criterion in S8 of FIG. 6 and S16 of FIG.

Then, in S9 of FIG. 6, it is determined whether each selected EMLMR link has received a response frame, and in S10, each EMLMR link that has received the response frame performs an EMLMR operation. Also, the response frame may be transmitted through each EMLMR link selected in S18 of FIG. 7, and the EMLMR operation may be executed in each EMLMR link that transmitted the response frame in S10.

In the first embodiment, when the selection is made based on the order in which the ELMMR links are established, the selection is made from the lowest order. You can choose.

In the first embodiment, the Basic variant Multi-Link element was described, but it may be a Basic Multi-Link element, and the EMLMR Supported MCS And NSS Set subfield may be an EMLMR Rx NSS subfield and an EMLMR Tx NSS subfield. In this case, the EMLMR Rx NSS subfield indicates the maximum number of spatial streams in reception and the EMLMR Tx NSS subfield indicates the maximum number of spatial streams in transmission.

A recording medium recording the program code of the software that realizes the above functions is supplied to the system or apparatus, and the computer (CPU, MPU) of the system or apparatus reads and executes the program code stored in the recording medium. may In this case, the program code itself read out from the storage medium implements the functions of the above-described embodiments, and the storage medium storing the program code constitutes the above-described device.

Examples of storage media for supplying program codes include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, and DVDs. can.

In addition, by executing the program code read by the computer, not only the above functions are realized, but also based on the instructions of the program code, the OS running on the computer may perform part or all of the actual processing. may be performed to implement the functions described above. OS is an abbreviation for Operating System.

Furthermore, the program code read from the storage medium is written to the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer. Then, based on the instructions of the program code, the CPU provided in the function expansion board or function expansion unit may perform part or all of the actual processing to realize the above functions.

The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

The present invention is not limited to the above embodiments, and various changes and modifications are possible without departing from the spirit and scope of the present invention. Accordingly, the following claims are included to publicize the scope of the invention.

This application claims priority based on Japanese Patent Application No. 2021-162357 submitted on September 30, 2021, and the entire contents of the description are incorporated herein.

Claims

A communication device that operates as a Multi-Link Device compliant with the IEEE802.11 series standard,
When performing frame exchange sequences on two links, a first Enhanced multi-link multi-radio (EMLMR) link and a second Enhanced multi-link multi-radio (EMLMR) link, the spatial stream of a particular link is described above. control means for controlling execution of a frame exchange sequence with the number of spatial streams in each of said first EMLMR link and said second EMLMR link without assigning them to said first EMLMR link and said second EMLMR link; A communication device comprising:
The control means determines the first EMLMR link or the second EMLMR link as a link for EMLMR operation, and replaces each of the number of spatial streams in the link determined as the link for EMLMR operation with non- Control so that other communication devices operating as AP MLD continue frame exchange after the initial frame exchange in the frame exchange sequence with the number of spatial streams up to the value defined in the EMLMR Supported MCS AND NSS SET subfield The communication device according to claim 1, characterized in that:
The control means continues the frame exchange sequence under any one of the control described in claim 1 and the control described in claim 2 based on the prediction of communication performance. Item 3. The communication device according to item 2.
The communication device according to any one of claims 1 to 3, wherein the control means deletes the EMLMR link on which the frame exchange sequence is performed when the frame exchange sequence ends.
A control method for a communication device operating as a Multi-Link Device conforming to the IEEE802.11 series standard,
When performing frame exchange sequences on two links, a first Enhanced multi-link multi-radio (EMLMR) link and a second Enhanced multi-link multi-radio (EMLMR) link, the spatial stream of a particular link is described above. a control step of controlling to execute a frame exchange sequence with a number of spatial streams in each of said first EMLMR link and said second EMLMR link without assigning them to said first EMLMR link and said second EMLMR link; A control method, comprising:
In the control step, the first EMLMR link or the second EMLMR link is determined as a link for EMLMR operation, and in the link determined as a link for EMLMR operation, instead of each of the number of spatial streams, non - Perform frame exchange after the initial frame exchange in the frame exchange sequence with the number of spatial streams that maximizes the value defined in the ELMMR Supported MCS AND NSS SET subfield by the own device or other communication device operating as the AP MLD 6. The control method according to claim 5, wherein the control is performed such that
In the control step, the frame exchange sequence is continued under either one of the control according to claim 1 and the control according to claim 2 based on the prediction of communication performance. The control method according to claim 6.
The control method according to any one of claims 5 to 7, characterized in that, in said control step, the EMLMR link on which the frame exchange sequence has been performed is deleted as the frame exchange sequence ends.
A program for causing a computer to function as each means of the communication device according to any one of claims 1 to 4.