Access point device, station device, control method, and program

Abstract

According to the present invention, when operating in an enhanced multi-link single radio (EMLSR) mode, an access point device that performs wireless communication based on the IEEE 802.11 standard determines whether a prescribed type of frame has been received from a station device connected to the access point device. Upon determining that the prescribed type of frame has been received, the access point device cancels the EMLSR mode and performs data communication with the station device. After the data communication has been performed, the access point device transitions the operation mode thereof to the EMLSR mode.

Description

Access point device, station device, control method, and program

[0001] The present invention relates to an access point device and a station device for communicating data.

[0002] In recent years, with the increase in the amount of data being communicated, the development of communication technologies such as wireless local area networks (LANs) has been progressing. The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as the main communication standard for wireless LANs. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax.

[0003] Furthermore, the IEEE802.11be standard, which is the successor to IEEE802.11ax, is being developed. A new function under consideration for the IEEE802.11be standard is multi-link communication, in which an AP and a STA establish multiple links on different frequency channels and communicate in parallel. Patent Document 1 also describes a mechanism for establishing multiple links for multi-link operation.

[0004] Furthermore, the specifications of the IEEE 802.11bn (UHR (Ultra High Reliability) standard), which is the successor to the IEEE 802.11be standard, are also under consideration.

[0005] Japanese Patent Application Laid-Open No. 2021-103805

[0006] In multi-link operation, a communication device is defined as using the STR (simultaneous transmit and receive) mode, which allows the device to simultaneously transmit and receive frames over multiple links. This mode consumes a lot of power because multiple links are on standby for communication. Therefore, the IEEE 802.11be standard defines the EMLSR (enhanced multi-link single radio) mode as a method for saving power in communication devices. This mode is defined only for non-AP MLD (non-access point multi-link device) in the IEEE 802.11be standard. In other words, there is currently no provision for applying the EMLSR mode to an AP MLD (access point multi-link device).

[0007] While operating in this EMLSR mode, the non-AP MLD waits to receive an initial control frame transmitted by the AP MLD simultaneously over multiple links (EMLSR links) established with the AP MLD.

[0008] Here, different channels are generally selected for each EMLSR link. The AP MLD then selects one link and transmits an initial control frame over that link. At this time, the AP MLD selects the optimal link (e.g., a link using an uncongested channel) and transmits the initial control frame. When the non-AP MLD receives the initial control frame, it exchanges data with the AP MLD over the link that received it. While operating in EMLSR mode, the non-AP MLD does not simultaneously transmit or receive over multiple links. Therefore, the non-AP MLD can save power consumption while still exchanging data with the AP MLD when it receives the initial control frame.

[0009] However, as mentioned above, no method for reducing power consumption of AP MLD, including EMLSR mode, has been specified, and reducing power consumption of AP MLD is one of the topics under discussion in the IEEE 802.11bn standard specifications.

[0010] In order to reduce the power consumption of AP MLD, it is desirable to be able to quickly respond to changes in the throughput or transmission delay required by non-AP MLDs connected to the AP MLD while achieving power saving. However, no method for achieving this has been considered at present.

[0011] An access point device according to one aspect of the present invention is an access point device that performs wireless communication based on the IEEE 802.11 standard, and is characterized by having: a determination means for determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is operating in EMLSR (enhanced multi-link single radio) mode; a communication control means for canceling the EMLSR mode and performing data communication with the station device when the determination means determines that a frame of the predetermined type has been received; and a transition means for transitioning to the EMLSR mode after data communication has been performed by the communication control means.

[0012] 1 is a diagram illustrating an example of the configuration of a network system. FIG. 2 is a diagram illustrating an example of the hardware configuration of a communication device (AP MLD / non-AP MLD). FIG. 3 is a diagram illustrating an example of the functional configuration of a communication device (AP MLD / non-AP MLD). FIG. 4 is a flowchart illustrating an example of control of AP MLD. FIG. 5 is a schematic diagram illustrating an example of information elements to be communicated. FIG. 6 is a schematic diagram illustrating an example of information elements to be communicated. FIG. 7 is a flowchart illustrating an example of control of non-AP MLD. FIG. 8 is a flowchart illustrating an example of control of AP MLD. FIG. 9 is a schematic diagram illustrating the relationship between modes and power saving. FIG. 10 is a schematic diagram illustrating the relationship between EMLSR mode and power saving. FIG. 11 is a schematic diagram illustrating a modified example.

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0014] The following embodiments and modifications disclose a configuration for quickly responding to changes in the throughput or transmission delay required by the non-AP MLD while operating the AP MLD in a power-saving manner. Also, as another aspect, a mechanism for the AP MLD to perform power-saving operation is disclosed.

[0015] 1 shows an example of the configuration of a network system according to this embodiment. The network system according to this embodiment includes one access point device (hereinafter simply referred to as an AP, AP STA, or access point) and two station devices (hereinafter simply referred to as STAs, Non-AP STAs, or stations).

[0016] The AP 101 and the STA 102 are configured to be able to communicate wireless frames conforming to the IEEE802.11bn standard, which is the successor to the IEEE802.11be standard and targets a maximum transmission speed of 46.08 Gbps.

[0017] IEEE stands for Institute of Electrical and Electronics Engineers. IEEE 802.11bn, the successor standard to IEEE 802.11be, has high reliability, low latency, and improved throughput during congestion as its main features. One of the goals of 802.11bn is to reduce power consumption in APs. Wireless frames communicated under this successor standard are also called UHR (Ultra High Reliability) PPDUs. PPDU stands for Physical Layer Protocol Data Unit.

[0018] The name UHR was chosen for convenience in light of the goals and key features of the successor standard, and may be a different name once the standard is fully developed. Similarly, the name IEEE 802.11bn may be a different name once the standard is fully developed. However, it should be noted that this specification and the appended claims are essentially applicable to all successor standards to the 802.11be standard.

[0019] 1 , the AP 101 is an access point that supports a multi-band function that provides networks using a plurality of different frequency channels. In this embodiment, the AP 101 is a dual-band access point that provides a 2.4 GHz band network and a 5 GHz band network, for example.

[0020] Furthermore, the AP 101 and the STA 102 of this embodiment can establish multiple communication links between the devices and perform multi-link communication. Hereinafter, the communication link will also be referred to simply as a link. The AP 101 that performs multi-link communication will also be referred to as an AP multi-link device (AP MLD) 101, and the STA 102 that performs multi-link communication will also be referred to as a non-AP MLD 102.

[0021] For example, AP 101 can establish link 103 in a 2.4 GHz band network with STA 102 and communicate therewith. In parallel with this, AP 101 and STA 102 can also establish link 104 in the 5 GHz band, for example, and communicate therewith. In this case, STA 102 executes multi-link communication in which it also communicates via link 103 in parallel with link 104. For convenience, in this embodiment, this mode in which two communication links are established and simultaneous communication is referred to as the normal mode of multi-link operation. Hereinafter, multi-link operation is also referred to as MLO.

[0022] In this embodiment, the normal mode is assumed to be an STR (simultaneous transmit and receive) mode in which the STA and AP can simultaneously transmit and receive data over two or more links. However, this is not limited to this. For example, the normal mode may be an NSTR mode in which a restriction is imposed such that a link pair in multi-link operation must be used for simultaneous transmission or simultaneous reception, and the AP 101 and the STA 102 communicate under this restriction. NSTR stands for nonsimultaneous transmit and receive.

[0023] In this way, the AP 101 can improve the throughput of communication with the STA 102 by establishing links with the STA 102 on a plurality of different frequency channels.

[0024] Incidentally, a non-AP MLD conforming to the IEEE 802.11be standard can also operate in a multi-link operation mode known as EMLSR (enhanced multi-link single radio) mode. A non-AP MLD operating in this mode establishes an EMLSR link with an AP MLD. In EMLSR mode, the link used for actual data communication is considered to be a single link, but this mode enables communication by dynamically switching the link actually used for communication based on factors such as wireless channel congestion. The non-AP MLD 102 of this embodiment also supports the EMLSR mode. A non-AP MLD 102 operating in EMLSR mode and on standby for communication operates in a state in which it scans the communication status of each channel of the EMLSR link. A non-AP MLD operating in a state of scanning the communication state in EMLSR mode does not transmit simultaneously on multiple links or wait to receive frames other than initial control frames while operating in that state.

[0025] Data communication of user data and the like using the EMLSR link between the AP MLD 101 and the non-AP MLD 102 is triggered by the transmission of an initial control frame. For example, when the non-AP MLD 102 detects through scanning that it has received an initial control frame from the AP MLD 101, it activates the link that received the frame to transmit data such as user data. Then, data communication of user data and the like is performed with the AP MLD over the activated link. This mechanism allows the non-AP MLD 102 to exchange data with the AP MLD with high throughput or low latency while saving power consumption.

[0026] Incidentally, power saving of AP MLDs is one of the topics being discussed in the study of the specifications of the IEEE 802.11bn standard. In light of this, in this embodiment, the concept of EMLSR mode is also applied to the AP MLD 101. In this case, a mechanism is provided that enables power saving operation on the AP side using the EMLSR mode and can quickly respond to changes in the throughput or transmission delay required by non-AP MLDs connected to the AP MLD.

[0027] A more detailed explanation follows. While FIG. 1 shows a network system consisting of one AP MLD 101 and one non-AP MLD 102 as an example, the number of non-AP MLDs constituting the network system may be greater than that shown. While the AP MLD 101 and non-AP MLD 102 are described as supporting UHR PPDU communication (transmission and reception), they can also be configured to support PPDU communication of legacy standards that predate the UHR standard. Specifically, the AP 101 and STA 102 can also be configured to support PPDU transmission and reception according to IEEE 802.11a / b / g / n / ac / ax / be standards, etc.

[0028] Furthermore, the frequency bands used by the AP MLD 101 and the non-AP MLD 102 are not limited to the 2.4 GHz band and 5 GHz band described above. For example, different frequency bands, such as the 6 GHz band, Sub 1 GHz band, or millimeter wave band, may be used. Furthermore, the AP 101 and the STA 102 can communicate using bandwidths such as 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, and 640 MHz. The bandwidths used by each communication device are not limited to these. Furthermore, although the present embodiment illustrates a case in which the links 103 and 104 performing multi-link communication are links of different frequency bands, this is not limiting. The AP MLD 101 can also perform multi-link communication with the non-AP MLD 102 using multiple links of the same frequency band but different channels.

[0029] The AP MLD 101 and non-AP MLD 102 can also be configured to support wireless communication based on other communication standards, such as Bluetooth (registered trademark), NFC, and Bluetooth (registered trademark) Low Energy (LE). NFC stands for Near Field Communication. The AP 101 and STA 102 can also be configured to support wired communication using an Ethernet (registered trademark) cable or wired communication using optical fiber. Specific examples of the AP 101 include, but are not limited to, a wireless LAN router and a personal computer (PC). The AP MLD 101 and non-AP MLD 102 may also be information processing devices, such as wireless chips that support the transmission and reception of UHR PPDUs. In this case, various controls can be performed by hardware circuits within the wireless chip. The wireless chip may be configured so that various processes are executed by cooperation between a processor, memory, and hardware circuit such as an ASIP (Application-Specific Instruction Set Processor) inside the wireless chip.

[0030] Specific examples of the STA 102 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, and wearable devices such as smart glasses.

[0031] 2 shows an example of the hardware configuration of the communication device (AP MLD 101, non-AP MLD 102). As an example of the hardware configuration, the communication device has a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and antennas 207 and 208.

[0032] The storage unit 201 is configured with ROM and / or RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. RAM stands for Random Access Memory, and ROM stands for Read Only Memory. Note that the storage unit 201 may be a storage medium such as a non-volatile storage device, such as a hard disk or SSD (Solid State Drive), in addition to memories such as ROM and RAM.

[0033] The control unit 202 is configured with, for example, a processor such as a CPU or MPU, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), etc. Here, CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 executes programs stored in the storage unit 201 and controls the entire device by operating hardware circuits such as the ASIC. Note that the control unit 202 may control the entire device in cooperation with the programs stored in the storage unit 201 and an OS (operating system).

[0034] The control unit 202 also controls the functional unit 203 to perform predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processes. For example, if the communication device is a camera such as a digital still camera or a smartphone equipped with a camera, the functional unit 203 is an imaging unit that captures images of the surroundings via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unit 203 is a printing unit that performs printing on a sheet such as paper based on print data obtained from the outside via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that performs projection of image data or video data obtained from the outside via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, for example. The data processed by the functional unit 203 may be data stored in the storage unit 201 or data communicated with another AP or STA via the communication unit 206 (described later). Furthermore, a communication device such as the AP 101 can also provide a network storage function such as a network attached storage (NAS). This function is provided to other communication devices as a web service such as a network storage service. For example, a communication device such as an STA connects to a network storage service provided by the AP MLD 101 using a protocol such as SMB, FTP, or WebDAV. The communication device such as the STA then uploads files to the storage service and downloads files from the storage. This upload and download data communication is also realized by communicating UHR PPDUs between devices.

[0035] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, and vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel.

[0036] The output unit 205 functions as a display unit that presents information to the user, and the input unit functions as a receiving unit that receives user operations.

[0037] The communication unit 206 controls wireless communications compliant with the IEEE 802.11 standard series and IP communications. In this embodiment, the communication unit 206 cooperates with the antennas 207 and 208 to execute communication control for transmitting and receiving UHR PPDUs, which are wireless frames of the UHR standard, and PPDUs conforming to earlier standards. The antennas 207 and 208 are antennas capable of transmitting and receiving signals in at least one frequency band, for example, the sub-GHz band, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, and the millimeter wave band. Note that, while a communication device equipped with two antennas is illustrated as an example in this embodiment, the present invention is not limited to this. The number of antennas may be three or more.

[0038] If the communication device is compatible with the aforementioned NFC standard, Bluetooth standard, wired communication standard, or the like, the communication unit 206 may be configured to control wireless communication or wired communication in accordance with these communication standards. The communication units 206 of the AP MLD 101 and non-AP MLD 102 each have a hardware circuit that decodes and encodes signals communicated over each link. Each antenna and hardware circuit is configured to be capable of individual power control. It is also possible to configure the device to have a separate communication unit corresponding to each link.

[0039] Next, the functional configuration of the AP MLD 101 and non-AP MLD 102 will be described with reference to Fig. 3. The communication devices such as the AP MLD 101 and non-AP MLD 102 have functional units such as a multi-link control unit 301, a multi-link communication setting UI unit 302, a frame generation unit 305, and a frame transmission / reception unit 306.

[0040] The multilink control unit 301 is a functional block that controls communication initiation processing for establishing one or more links used by a communication device for wireless communication with a partner device, mode determination and change processing, link addition and deletion processing after communication has started, and communication termination processing for deleting all links. Specifically, the connection processing is composed of authentication processing, association processing, and 4-way handshake processing. In the case of AP MLD 101, the partner device is an STA such as non-AP MLD 102, and in the case of non-AP MLD 102, the partner device is an AP such as AP MLD 101. The multilink control unit 301 also controls the power saving mode. Specifically, when the power saving mode is enabled, it performs power control such as stopping the power supply to some hardware circuits.

[0041] The multi-link communication setting UI (User Interface) unit 302 provides a setting screen as a UI for the user to input settings related to multi-link communication. The UI unit 302 is also a functional block that accepts user operations on the setting screen via the input unit 204 and stores the settings in the storage unit 201 as operation settings of the communication device. The UI unit 302 accepts a setting change operation for enabling or disabling power saving mode via a setting screen (not shown). The UI unit 302 also stores operation settings related to the AP power saving mode corresponding to the setting change operation in the storage unit 201. The operation settings are used as appropriate to determine whether to execute the control of the flowchart described below.

[0042] Returning to the explanation of FIG. 3, the frame generation unit 305 is a block that generates UHR PPDUs, which are wireless frames for communicating with the outside. The frame transmission / reception unit 306 transmits the wireless frames generated by the frame generation unit 305 and receives wireless frames from the other device. In the case of the non-AP MLD 102, it transmits Probe Request frames, Association Request frames, and data frames to the AP. The non-AP MLD 102 also transmits Authentication Request frames and other frames for connection processing to the AP. The AP also transmits a Request To Send (RTS) frame, a Null Data PPDU (NDP) frame, an enhanced multi-link (EML) Operating Mode Notification frame, and an initial control frame to the AP.

[0043] In the case of the AP MLD 101, it transmits a beacon frame, a probe response frame, an association response frame, and a data frame to the STA. The AP MLD 101 also transmits an association request frame, an authentication request frame, and other frames for connection processing to the STA. It also transmits the above-mentioned initial control frame to the STA as a non-AP MLD.

[0044] <Communication Control Using EMLSR Mode> Next, communication control using the EMLSR mode of this embodiment will be described with reference to the flowcharts of FIGS. 4 and 8 to 10 and the schematic diagrams of information elements of FIGS.

[0045] Figures 4 and 9 are flowcharts explaining an example of communication control in the AP MLD 101, and Figures 8 and 10 are flowcharts explaining an example of communication control in the non-AP MLD 102. Figures 5 to 7 are schematic diagrams explaining information elements communicated between devices.

[0046] Each process shown in the flowcharts of Figures 4 and 9 is executed by the processor of the control unit 202 of the AP MLD 101 executing a computer program stored in the storage unit 201. Note that some processes such as transmission and modulation are realized by the processor of the control unit 202 working in cooperation with various processors, ASICs, DSPs, FPGAs, etc. that constitute the communication unit 206, and the ASICs, DSPs, FPGAs, etc. that constitute the antenna and control unit 202. Note that this is not a limitation, and it is of course also possible to configure the communication unit 206 and the antenna to work in cooperation to execute each process shown in the flowcharts. Note that when it is desired to clearly indicate the subject of the process, the functional unit described in Figure 3 will be used as the subject in the description.

[0047] 8 and 10 are performed by the processor of the control unit 202 of the non-AP MLD 102 executing a computer program stored in the storage unit 201. Note that some of the processing, such as transmission and modulation, is realized by the processor of the control unit 202 working in cooperation with the various processors, ASICs, DSPs, FPGAs, etc. that make up the communication unit 206, and the ASICs, DSPs, FPGAs, etc. that make up the control unit 202.

[0048] However, the present invention is not limited to this, and it is of course possible to configure the communication unit 206 and the antenna to cooperate to execute each process shown in the flowchart. When it is desired to clearly indicate the subject of the process, the functional unit described in FIG. 3 will be used as the subject in the description.

[0049] The operation of the AP MLD 101 will be described with reference to Fig. 4. The processes shown in Fig. 4 are excerpts of a series of processes from when the AP MLD 101 starts operating as an MLO until it starts operating in EMLSR mode, which is an MLO mode. Note that if the control unit 202 of the AP MLD 101 determines that an operation setting that does not use the power saving mode is stored in the storage unit 201, it executes control of a normal mode (not shown) instead of the control shown in Fig. 4. In other words, it is assumed that the controls shown in Fig. 4 are executed when an operation setting that uses the power saving mode is stored in the storage unit 201.

[0050] A brief description of the normal mode (not shown) follows. In normal mode, the AP MLD 101 establishes and maintains the two networks described above. STAs such as the non-AP MLD 102 are allowed to connect to the AP MLD 101 in EMLSR mode. For STAs connected to the AP MLD 101 in EMLSR mode, the EMLSR link is activated using the initial control frame as described above as a trigger. Data communication, such as user data, can then be performed using the activated EMLSR link. Furthermore, the AP MLD 101 in normal mode provides data communication using multiple links simultaneously as appropriate for non-AP MLDs connected to the AP MLD 101 in STR mode or NSTR mode.

[0051] Returning to the explanation of FIG. 4 , the control when the operation setting for using the power saving mode is performed will be described. First, the MLO device search phase in which the STA searches for an AP to connect to, and the MLO setup phase in which the STA performs a multilink connection to the AP found as a result of the search will be described. In S400, the multilink control unit 301 cooperates with the frame generation unit 305, frame transmission / reception unit 306, communication unit 206, and antennas 207-208 to execute control for including in a frame and transmitting information indicating that the EMLSR mode is to be enabled. The frame transmitted in S400 is the frame transmitted in the MLO device search phase and the MLO setup phase.

[0052] More specifically, the AP MLD 101 includes information indicating that it is about to enable the EMLSR mode in a Beacon frame or a Probe Response frame. Hereinafter, the information indicating that it is about to enable the EMLSR mode will be simply referred to as "enablement information." Furthermore, information indicating that it is about to disable the EMLSR mode, which will be described later, will be simply referred to as "disablement information."

[0053] The Beacon frame is a frame that the AP MLD 101 transmits periodically at a predetermined cycle (for example, every 100 ms). The Probe Response frame is a frame that is transmitted as a response to a Probe Request frame received from an STA such as the non-AP MLD 102. However, the present invention is not limited to this, and it is also possible to configure the frame to transmit information indicating that the EMLSR mode is being enabled or disabled at any other timing during the connection destination search phase or connection phase, or in any other frame.

[0054] As will be described in detail later, when the STA of the opposing device completes the search process in the search phase and starts connection processing to the AP MLD 101, the AP 101 performs a multi-link setup procedure.

[0055] The AP MLD 101 may include validation information in an Association Response frame or a Reassociation Response frame transmitted in the Multi-Link Setup procedure. These frames are response frames that store response information when an Association Request frame or a Reassociation Request frame is received from an STA such as the non-AP MLD 102.

[0056] The AP MLD 101 may also transmit a frame including a UHR Operation element that controls the operation of a device that complies with the IEEE802.11 UHR standard to a STA such as the non-AP MLD 102, and include activation information in the element.

[0057] A specific example of including activation information in a UHR Operation element will be described with reference to Figure 5. The UHR Operation element is composed of fields 500 to 506. The UHR Operation element includes a UHR Operation Parameters field 503 and an EMLSR Control field 506. The UHR Operation element also includes the same type of information as the EHT Operation element defined in IEEE 802.11be.

[0058] An Element ID field 500, a Length field 501, and an Element ID Extension field 502 each contain information similar to the fields of the same name defined in the IEEE 802.11be standard.

[0059] The UHR Operation Parameters field 503 includes an EMLSR Control Present subfield 515. The field 503 also includes information similar to the EHT Operation Parameters field defined in the IEEE 802.11be standard.

[0060] The Basic UHR-MCS And Nss Set field 504 contains information similar to the Basic EHT-MCS And Nss Set field defined in the IEEE 802.11be standard. The UHR Operation Information field 505 contains information similar to the EHT Operation Information field. The EMLSR Control field 506 contains information for controlling device operations related to the EMLSR mode. Details of this field will be described later.

[0061] The UHR Operation Parameters field 503 is composed of subfields 510 to 515. The UHR Operation Information Present subfield 510 contains information similar to the EHT Operation Information Present subfield defined in the IEEE 802.11be standard. The Disabled Subchannel Bitmap Present subfield 511 contains information similar to the subfield of the same name defined in the IEEE 802.11be standard. The UHR Default PE Duration subfield 512 contains information similar to the EHT Default PE Duration subfield defined in the IEEE 802.11be standard. The Group Address BU Indication Limit subfield 513 contains the same information as the subfield of the same name defined in the IEEE 802.11be standard. The Group Address BU Indication Exponent subfield 514 contains the same information as the subfield of the same name defined in the IEEE 802.11be standard. The EMLSR Control Present subfield 515 indicates whether the UHR Operation element includes the EMLSR Control field 506. This subfield consists of 1 bit. If its value is 1, it means that the UHR Operation element includes the EMLSR Control field 506. On the other hand, if it is 0, it means that the UHR Operation element does not include the EMLSR Control field 506.

[0062] The EMLSR Control field 506 is present if the value of the EMLSR Control Present subfield 515 is 1, and is absent if the value is 0. This field consists of subfields 520 and 521. The EMLSR Mode subfield 520 indicates whether the EMLSR mode is to be enabled.

[0063] This subfield consists of 1 bit. If its value is 1, it means that the EMLSR mode is about to be enabled. On the other hand, if its value is 0, it means that the EMLSR mode is about to be disabled. The EMLSR Link Bitmap subfield 521 indicates the link ID of the link to be used as the EMLSR link. This subfield consists of 16 bits, and the i-th bit corresponds to the state of the link whose Link ID is i. For example, bit 0 corresponds to the state of the link whose Link ID is 0, bit 1 corresponds to the state of the link whose Link ID is 1, and so on.

[0064] Storing a 1 in the EMLSR Mode subfield 520 is an example of including enablement information in the frame, and storing a 0 in the EMLSR Mode subfield 520 is an example of including disablement information in the frame.

[0065] The AP MLD 101 that transmitted the activation information receives information indicating whether to permit or deny the AP MLD from enabling the EMLSR mode as a response to the activation information from an MLD device such as the non-AP MLD 102. Hereinafter, information permitting the AP MLD to enable the EMLSR mode will be referred to as "permission information," and information denying the AP MLD from enabling the EMLSR mode will be referred to as "denial information."

[0066] This information can be included in a Probe Request frame, an Association Request frame, or a Reassociation Request frame transmitted by an MLD device such as the non-AP MLD 102.

[0067] Specifically, an MLD device such as the non-AP MLD 102 includes a Probe Request Multi-Link element in a Probe Request frame, which can be configured to include permission information or denial information.

[0068] 6 shows an example of a Probe Request Multi-Link element. The Probe Request Multi-Link element is composed of fields 600 to 605. The Probe Request Multi-Link element includes a Multi-Link Control field 603 and a Common Info field 604. With the exception of some subfields, fields 603 and 604 contain the same information as the elements of the same name specified in the IEEE 802.11be standard. An Element ID field 600, a Length field 601, and an Element ID Extension field 602 each contain the same information as the fields of the same name specified in IEEE 802.11be. The Multi-link Control field 603 contains the same information as the field of the same name defined in the IEEE 802.11be standard, except for some subfields in the Presence Bitmap subfield 612. Details of this field will be described later. The Common Info field 604 contains the same information as the field of the same name defined in the IEEE 802.11be standard, except for the inclusion of the EMLSR Control subfield 632.

[0069] This field will be described in more detail below. The Link Info field 605 contains the same information as the field of the same name defined in the IEEE 802.11be standard.

[0070] The Multi-link Control field 603 is made up of subfields 610 to 612. The Type subfield 610 and the Reserved subfield 611 each contain the same information as the subfields of the same names defined in the IEEE 802.11be standard.

[0071] The Presence Bitmap subfield 612 consists of subfields 620 and 621. The AP MLD ID Present subfield 620 contains the same information as the subfield of the same name defined in the IEEE 802.11be standard. The EMLSR Control Present subfield 612 indicates whether the Probe Request Multi-Link element includes the EMLSR Control subfield 632 in its Common Info 604 field. This subfield consists of 1 bit. If its value is 1, it means that the Probe Request Multi-Link element includes the EMLSR Control subfield 632. On the other hand, if it is 0, it means that the Probe Request Multi-Link element does not include the EMLSR Control subfield 632 .

[0072] The Common Info field 604 is made up of subfields 630 to 632. A Common Info Length subfield 630 and an AP MLD ID subfield 631 each contain the same information as the subfields of the same name defined in the IEEE 802.11be standard.

[0073] The EMLSR Control subfield 632 is present when the value of the EMLSR Control Present subfield 621 is 1, and is not present when the value is 0. This subfield consists of an EMLSR Mode subfield 640 and an EMLSR Link Bitmap subfield 641. Setting the EMLSR Mode subfield 640 to 1 means that the AP MLD 101 is permitted to enable the EMLSR mode. On the other hand, setting the EMLSR Mode subfield 640 to 0 means that the AP MLD 101 is not permitted to enable the EMLSR mode.

[0074] Furthermore, when an MLD device responds with permission information or denial information in an Association Request frame or a Reassociation Request frame, the information is included in a Basic Multi-Link element.

[0075] The information elements in this case will be explained using Figure 7. Figure 7 shows an example of the configuration of a Basic Multi-Link element included in an Association Request frame or Reassociation Request frame transmitted by the non-AP MLD 102. The Basic Multi-Link element is composed of fields 700 to 705. Each field contains the same information as the element of the same name specified in IEEE 802.11be, except for some subfields in the Multi-link Control field 703 and the Common Info field 704. The Element ID field 700, Length field 701, and Element ID Extension field 702 each contain the same information as the field of the same name specified in the IEEE 802.11be standard. The Multi-link Control field 703 contains the same information as the field of the same name defined in the IEEE 802.11be standard, except for some subfields in the Presence Bitmap subfield 712. Details of this field will be described later. The Common Info field 704 contains the same information as the field of the same name defined in the IEEE 802.11be standard, except for the inclusion of an EMLSR Control subfield 739. Details of this field will be described later. The Link Info field 705 contains the same information as the field of the same name defined in the IEEE 802.11be standard. The Multi-link Control field 703 is made up of subfields 710 to 712. The Type subfield 710 and the Reserved subfield 711 each contain the same information as the subfields of the same name defined in the IEEE 802.11be standard.

[0076] The Presence Bitmap subfield 712 is made up of subfields 720 to 726 and the EMLSR Control Present subfield 621 .

[0077] The subfield 712 includes a Link ID Info Present subfield 720, a BSS Parameters Change Count Present subfield 721, a Medium Synchronization Delay Information Present subfield 722, an EML Capabilities Present subfield 723, an MLD Capabilities and Operations Present subfield 724, an AP MLD ID Present subfield 725, and an Extended MLD Capabilities and Operations Present subfield 726. Each of the subfields 720 to 726 contains the same information as the subfields of the same name defined in the IEEE 802.11be standard. The EMLSR Control Present subfield 621 is the same as that in the Probe Request Multi-Link element described above.

[0078] The Common Info field 704 is made up of subfields 730 to 738 and the EMLSR Control subfield 632 . The field 704 includes a Common Info Length subfield 730, an MLD MAC Address subfield 731, a Link ID Info subfield 732, a BSS Parameters Change Count subfield 733, a Medium Synchronization Delay Information subfield 734, an EML Capabilities subfield 735, an MLD Capabilities and Operations subfield 736, an AP MLD ID subfield 737, and an Extended MLD Capabilities and Operations subfield 738. Each of the subfields 730 to 737 contains information similar to the subfields of the same name defined in the IEEE 802.11be standard. The EMLSR Control subfield 632 is the same as that in the Probe Request Multi-Link element described above. That is, the Basic Multi-Link element also contains the EMLSR Mode subfield 640 and EMLSR Link Bitmap subfield 641 described above.

[0079] When the non-AP MLD 102 transmits permission information, it stores 1 in the EMLSR Mode subfield of the UHR Operation element, whereas when it transmits denial information, it stores 0 in the EMLSR Mode subfield of the UHR Operation element.

[0080] Returning to the explanation of Figure 4, the AP MLD 101 and non-AP MLD 102 execute the multi-link setup procedure by exchanging frames containing information about the multi-link communication described in Figures 5 to 7. In other words, they exchange requests and acceptance / non-acceptance of MLO, such as which link to use in multi-link communication and which mode to operate in. Then, they establish multi-link communication using the agreed-upon operating mode and link.

[0081] In S401, the control unit 301 determines whether the multi-link setup procedure has been completed successfully. If it is determined that the multi-link setup procedure has been completed successfully, the process proceeds to S402. If it is determined that the multi-link setup procedure has not been completed successfully, the control unit 301 continues exchanging frames for the setup procedures.

[0082] In S402, the control unit 301 determines whether a frame including permission information has been received during the exchange with the AP MLD 102 with which Multi-Link communication has been established, as shown in the procedure described above.

[0083] If it is determined that a frame including permission information has been received, the process proceeds to S403. On the other hand, if it is not determined that a frame including permission information has been received (i.e., if it is determined that a frame including denial information has been received, or if the response frame does not include an information element corresponding to denial information or permission information), the process proceeds to S404.

[0084] In S403, the control unit 301 starts the EMLSR mode in cooperation with each unit such as the communication unit 206 and the antennas 207 and 208. Specific control after starting the EMLSR mode will be described later using the flowchart in FIG.

[0085] Meanwhile, in S404, the control unit 301 starts operation in the normal mode in cooperation with each unit such as the communication unit 206 and the antennas 207 and 208. The operation in the normal mode may be performed by performing the data communication control described at the beginning of FIG.

[0086] Next, the search phase processing and MLO setup phase processing executed by the non-AP MLD 102 will be explained using Fig. 8. This operation is executed when the non-AP MLD 102 starts search phase processing to search for AP MLDs that support MLO. Note that the processes shown in Fig. 8 and Fig. 10 are excerpts of the processing when the non-AP MLD 102 determines the MLO mode and performs multi-link communication with the AP MLD 101.

[0087] The non-AP MLD 102 searches for surrounding APs by scanning beacon frames emitted by the surrounding APs, transmitting probe request frames to the surrounding APs, and receiving probe response frames.The non-AP MLD 102 then exchanges information elements related to Multi-Link described in Figures 5 to 7 to discover AP MLDs that support MLO and establish a connection with the discovered AP MLDs.

[0088] In S800, the control unit 301 determines whether or not it has received a response frame to the search or a frame for MLO setup from the AP MLD 101, the response frame including information (activation information) indicating that the EMLSR mode is being activated.

[0089] If it is determined that a frame including validation information has been received, the process proceeds to S801. On the other hand, if it is determined that a frame including validation information has not been received (i.e., if a frame including invalidation information has been received or if it is determined that a frame including neither invalidation information nor validation information has been received), the process proceeds to S802.

[0090] In S801, the control unit 301 determines whether or not to permit the enabling of the EMLSR mode. At this time, the non-AP MLD 101 can be configured to make this determination based on information previously stored in the storage unit 201. Next, in S802, the control unit 301 cooperates with the generating unit 305, the transmitting / receiving unit 306, the communication unit 206, the antennas 207 and 208, etc., to transmit an inquiry frame and / or a setup frame containing information corresponding to the determination result. Specifically, if the non-AP MLD 102 determines to permit the enabling of the EMLSR mode, it transmits the frame containing permission information. On the other hand, if the non-AP MLD 102 determines not to permit the enabling of the EMLSR mode, it transmits the frame containing rejection information.

[0091] In S803, the control unit 301 determines whether the multi-link setup procedure has been completed successfully. If it is determined that the multi-link setup procedure has been completed successfully, the process proceeds to S804. If it is determined that the multi-link setup procedure has not been completed successfully, the process proceeds to S800, where the exchange of frames for various procedures such as search and setup continues.

[0092] In S804, the control unit 301 determines whether or not the AP MLD 101 has offered permission to enable the EMLSR mode during procedures such as discovery and setup. If the control unit 301 determines that permission to enable the EMLSR mode has been offered, the process proceeds to S805. On the other hand, if the control unit 301 does not determine that permission to enable the EMLSR mode has been offered (i.e., if denial information has been transmitted or if enable / disable information is not included in the frame received from the AP), the process proceeds to S806.

[0093] In S805, the control unit 301 cooperates with the generation unit 305, the transmission / reception unit 306, the communication unit 206, the antennas 207 to 208, etc. to start operation in EMLSR mode. Details of this operation will be described later using FIG. 10. Meanwhile, in S806, the control unit 301 cooperates with the generation unit 305, the transmission / reception unit 306, the communication unit 206, the antennas 207 to 208, etc. to start control for communication with the AP in a normal mode (such as STR mode). In this normal mode, general multi-link communication is performed, such as simultaneous data communication using multiple link pairs that have established communication.

[0094] <Communication Control in EMLSR Mode> Next, communication control after starting operation in the EMLSR mode will be described with reference to FIGS.

[0095] First, the control after the AP MLD 101 starts operating in the EMLSR mode will be described with reference to Fig. 9. In S900, the control unit 301 of the AP MLD 101, in cooperation with the communication unit 206, listens to multiple EMLSR links and determines whether a predetermined type of frame has been received from an EMLSR non-AP MLD. An EMLSR non-AP MLD is a non-AP MLD, such as the non-AP MLD 102, that has already established a connection with the AP MLD 101 and is operating in the EMLSR mode.

[0096] The EMLSR link that the AP MLD 101 listens to in S900 is the link presented in the procedure described in Fig. 4. That is, it is the link that the AP MLD 101 presented to the EMLSR non-AP MLD in the EMLSR Link Bitmap subfield 521 of the UHR Operation element. In this embodiment, the description will be given assuming that the link 103 and the link 104 described in Fig. 1 are presented as EMLSR links.

[0097] At this time, the AP MLD 101 uses antennas 207 and 208 to listen to received signals on both the channel corresponding to link 103 and the channel corresponding to link 104 .

[0098] The predetermined type of frame is a frame that causes an operation to execute data exchange with the EMLSR mode temporarily released, or an initial control frame for executing data exchange while maintaining the EMLSR mode. Hereinafter, a frame that causes an operation to execute data exchange with the EMLSR mode temporarily released will be referred to as an EMLSR mode temporary release frame.

[0099] These frames may be newly defined Media Access Control (MAC) frames to indicate temporary release. The initial control frame may also be a newly defined MAC frame for the purpose of informing the AP that the STA wishes to start communication over the EMLSR link. These frames may be management frames or data frames.

[0100] Furthermore, an existing specific type of control frame or data frame may be regarded as an EMLSR mode temporary release frame when operating in the EMLSR mode.

[0101] For example, an RTS frame, which is a frame used by non-AP MLD to request a transmission opportunity, is an example of an EMLSR mode temporary release frame.An NDP frame, which is a data frame that does not contain any substantial data, is also an example of an EMLSR mode temporary release frame.

[0102] It should be noted that the EMLSR mode temporary release frame and the initial control frame are defined as MAC frames of different types, or MAC frames of the same type but with different values ​​for fields within the frame.

[0103] Also, an EML Operating Mode Notification frame in which the value of the EMLSR Mode subfield of the EML Control field is 0 is an example of an EMLSR mode temporary release frame.

[0104] Next, in S901, the control unit 301 determines whether the frame received in S900 is an EMLSR mode temporary release frame. If the frame received in S900 is an EMLSR mode temporary release frame, the process proceeds to S902. If the frame received in S900 is not an EMLSR mode temporary release frame (i.e., if it is an initial control frame), the process proceeds to S905.

[0105] In S902, the control unit 301 temporarily cancels the EMLSR mode and transitions to normal mode. Then, communication is performed with the non-AP MLD that sent the EMLSR mode temporary release frame to reconfigure the MLO operation mode. The MLO operation mode with the non-AP MLD is then switched to a communication mode utilizing multiple links, such as STR mode or NSTR mode. Then, data communication utilizing multiple links is performed. When data communication is completed, the AP MLD 101 re-transitions to EMLSR mode. When re-transitioning, the AP MLD 101 may notify the non-AP MLD connected to the AP MLD 101 of activation information. Alternatively, the AP MLD 101 may automatically re-transition to EMLSR mode upon completion of data communication. When re-transitioning is complete, the control unit 301 proceeds to S906. In S902, data communication can be performed using multiple links simultaneously. Therefore, while maintaining the EMLSR mode described later, data exchange can be performed with a higher throughput or a smaller transmission delay compared to an operation in which data communication is performed via one EMLSR link.

[0106] Next, control when it is not determined that a frame of a predetermined type has been received will be described. The control unit 301 determines whether data to be communicated with the EMLSR non-AP MLD exists. For example, when data to be transmitted to the EMLSR non-AP MLD occurs, the control unit 301 determines that data to be communicated with the EMLSR non-AP MLD exists. This data is, for example, data addressed to the EMLSR non-AP MLD and received from an external network such as the Internet via a wired LAN or the like. Note that this data may also be data addressed to the EMLSR non-AP MLD and received from a communication device or the like connected to the wired LAN.

[0107] If the control unit 301 determines that there is data to be communicated with the EMLSR non-AP MLD, the process proceeds to S904; if it does not determine that there is data to be communicated with the EMLSR non-AP MLD, the process proceeds to S906.

[0108] In S904, the control unit 301 cooperates with the generation unit 305, the transmission / reception unit 306, the communication unit 206, the antennas 207-208, etc. to transmit an initial control frame to the EMLSR non-AP MLD that is the destination of the data communication. More specifically, the AP MLD 101 transmits an initial control frame defined in the IEEE802.11be standard to the EMLSR non-AP MLD that is the destination of the EMLSR data communication via either link 103 or link 104. When the transmission is complete, the process proceeds to S905. The control unit 301 may determine which link to use to transmit the initial control frame based on the communication congestion status, etc.

[0109] In S905, the control unit 301 cooperates with the generation unit 305, the transmission / reception unit 306, the communication unit 206, the antennas 207 and 208, etc. to enable one link that has transmitted or received the initial control frame so that normal data communication can be performed. Then, data exchange with the non-AP MLD is performed over the enabled link. In other words, data exchange is performed over the EMLSR link that has been enabled for communication while maintaining the EMLSR mode.

[0110] Note that after receiving an EMLSR mode temporary release frame or an initial control frame, the AP MLD 101 may transmit a response frame to the sender of the frame before executing data exchange. A CTS (Clear To Send) frame or an ACK frame may be used as the response frame. Furthermore, the AP MLD 101 may also perform control equivalent to CTS when transmitting an initial control frame to a non-AP MLD in order to transmit a data frame. In this case, the AP MLD 101 may transmit a CTS-to-self frame over the enabled EMLSR link before executing data exchange.

[0111] Furthermore, the EMLSR mode temporary release frame or the initial control frame and the subsequent data exchange may be performed in a single frame exchange sequence. Alternatively, each may be included in a different frame exchange sequence. In this embodiment, data exchange refers to a process of transmitting a data frame from one side to another and a series of exchanges in which one side transmits a frame containing information indicating to the other side that the data frame has been received. The frame containing information indicating to the other side that the data frame has been received is, for example, an ACK frame or a Block ACK frame.

[0112] In S906, the control unit 301 determines whether to terminate operation in EMLSR mode. Specifically, the AP MLD 101 determines to terminate operation in EMLSR mode when it determines that it has received a setting change operation to disable power saving mode. It also determines to terminate operation in EMLSR mode when the amount of data communication with the non-AP MLD is on the rise, or when it infers that the amount of data communication is on the rise based on past communication trends, etc. It may also be determined to terminate operation in EMLSR mode when the number of STAs connected to the non-AP MLD exceeds a predetermined value. Furthermore, when the amount of data communication is not on the rise, etc., the control unit 301 determines not to terminate operation in EMLSR mode.

[0113] If the control unit 301 determines not to terminate operation in EMLSR mode, it proceeds to S900. On the other hand, if the control unit 301 determines to terminate operation in EMLSR mode, it transmits a frame notifying that effect. This frame may be a frame including information (disabling information) indicating that EMLSR mode is being disabled. It may also be an EML Operating Mode Notification frame in which the EMLSR Mode subfield of the EML Control field has a value of 0. When the AP MLD 101 terminates operation in EMLSR mode, it begins operating as a normal MLO capable of simultaneous communication in the network corresponding to link 103 and the network corresponding to link 104.

[0114] Finally, the control after the non-AP MLD 102 starts operating in the EMLSR mode will be described with reference to FIG.

[0115] In S1000, the control unit 301 of the non-AP MLD 102 determines whether data to be transmitted has occurred to the AP MLD 101. If it is determined that data to be transmitted has occurred, the process proceeds to S1002, and if it is not determined that data to be transmitted has occurred, the process proceeds to S1006.

[0116] In S1006, the control unit 301, in cooperation with each unit, determines whether or not an initial control frame has been received from the AP MLD 101. If it is determined that an initial control frame has been received from the AP MLD 101, the process proceeds to S1004, and if it is not determined that an initial control frame has been received, the process proceeds to S1005.

[0117] In S1002, the control unit 301 determines whether to transition to a normal Multi-Link mode such as STR mode and perform communication in order to exchange data.

[0118] When the non-AP MLD 102 determines that a situation has arisen in which data exchange using multiple links is required, it determines that communication should be performed by transitioning to the normal multi-link mode. More specifically, when the control unit 301 determines that data that requires data exchange with high throughput or low latency has occurred, it determines that communication should be performed by transitioning to the normal multi-link mode. If the control unit 301 determines that communication should be performed by transitioning to the normal multi-link mode, it proceeds to S1003, and if it does not determine that communication should be performed by transitioning to the normal multi-link mode, it proceeds to S1004.

[0119] In S1003, the control unit 301 cooperates with the various units to transmit the EMLSR mode temporary release frame described above to the AP MLD 101. Then, the control unit 301 transitions to a normal Multi-Link mode such as STR mode and executes data exchange with the AP MLD 101. Once the data exchange is complete, mode negotiation with the AP MLD 101 is performed again and the mode is re-transitioned to the EMLSR mode. Alternatively, the mode is automatically re-transitioned to the EMLSR mode upon completion of the data exchange. Once the re-transition is complete, the control unit 301 advances the process to S1005.

[0120] Meanwhile, in S1004, the control unit 301 cooperates with each unit to transmit an initial control frame to the AP MLD 101. Note that if an initial control frame is received from the AP MLD in S1006, the process of transmitting the initial control frame to the AP MLD 101 is omitted. Next, the control unit 301 cooperates with each unit to enable one link that transmitted or received the initial control frame so that normal data communication can be performed. Then, data exchange with the AP MLD 101 is performed via the enabled link. In other words, data exchange is performed via the EMLSR link that has been enabled for communication while maintaining the EMLSR mode. When the control unit 301 determines that the series of data exchanges has been completed, the process proceeds to S1005.

[0121] The control unit 301 transmits the EMLSR mode temporary release frame or the initial control frame through one of the EMLSR links. The control unit 301 can appropriately determine which EMLSR link to use to transmit the frame, taking into account the channel usage status, etc.

[0122] As described above, the non-AP MLD 102 may be configured to transmit an EMLSR mode temporary release frame or an initial control frame, and then perform actual data exchange only after receiving a response frame. In this case, if the non-AP MLD 102 does not receive a response frame from the AP MLD 101, it may not perform data exchange and may retransmit the EMLSR mode temporary release frame or the initial control frame. Alternatively, if the non-AP MLD 102 transmits an EMLSR mode temporary release frame but does not receive a response frame, it may be controlled to consider the AP MLD 101 to be operating in EMLSR mode. In this case, the non-AP MLD 102 may attempt data exchange only over the EMLSR link through which it transmitted the EMLSR mode temporary release frame.

[0123] Returning to the explanation of FIG. 10 , in S1005, the control unit 301 determines whether to terminate the EMLSR mode. If it is determined that the EMLSR mode should be terminated, the EMLSR mode is terminated and a transition to a normal multi-link mode such as STR mode is made. On the other hand, if it is determined that the EMLSR mode should not be terminated, the process proceeds to S1000. Specifically, the control unit 301 determines to terminate operation in the EMLSR mode when the amount of data communication with the AP MLD 101 is on the rise or when it infers that the amount of data communication is on the rise based on past communication trends, etc. Furthermore, if the amount of data communication is not on the rise, etc., the control unit 301 determines not to terminate operation in the EMLSR mode and proceeds to S1000.

[0124] The above-described processing makes it possible to operate the AP MLD in a power-saving manner while quickly responding to changes in the throughput or transmission delay amount required by the non-AP MLD.

[0125] The effect of this embodiment will be described with reference to Fig. 11. Fig. 11 is a schematic diagram illustrating the relationship between the EMLSR mode and the normal mode such as the STR mode in this embodiment and power consumption.

[0126] The AP MLD 101 operates in the EMLSR mode during a period 1100 before transmitting a response frame 1111 to the EMLSR mode temporary release frame 1110 .

[0127] While operating in EMLSR mode, the AP MLD 101 waits to receive an EMLSR mode temporary release frame or an initial control frame over multiple EMLSR links. However, the AP MLD 101 can actually receive and decode data frames over only one link. It can also transmit frames over only one link. While operating in EMLSR mode, the AP MLD 101 waits to receive frames over multiple EMLSR links. In this case, the control unit 301 cooperates with each component to control the supply of power to circuits for listening to multiple channels corresponding to the multiple EMLSR links and to circuits for transmitting and receiving frames over one link. In this case, the control unit 301 stops the supply of power and / or clock signals to circuits that are necessary for simultaneously exchanging frames over two links but that can be powered down in EMLSR mode without causing any problems. For example, the control unit 301 controls so that power and / or clock signals are not supplied to circuit 2 shown in FIG. 12 . This reduces the power consumption required to maintain circuits that are necessary for simultaneously exchanging frames over two links but do not need to operate in EMLSR mode, such as circuit 2 shown in Fig. 12. This reduces power consumption compared to the period during which normal multi-link operation is performed.

[0128] Next, the non-AP MLD 102 transmits an EMLSR mode temporary release frame 1110 to the AP MLD 101 via one of the EMLSR links.

[0129] When the AP MLD 101 receives the EMLSR mode temporary release frame 1110 from the non-AP MLD 102, it transmits a response frame 1111 to the non-AP MLD 102 via one of the EMLSR links. Then, it releases the EMLSR mode and starts normal multi-link operation. At this time, as shown in Figure 12 for normal multi-link operation, power is supplied to the circuits required to exchange frames simultaneously via two links, and actual data exchange also takes place, resulting in a large power consumption.

[0130] During a period 1101, the AP MLD 101 exchanges data with the non-AP MLD 102 over multiple links using a normal mode such as the STR mode or the NSTR mode.

[0131] In the data exchange procedure, the AP MLD 101 receives a data frame 1112 and transmits a response frame (here, an ACK frame 1113) to the non-AP MLD 102. When a series of data exchanges is completed, the AP MLD 101 transitions back to the EMLSR mode (period 1102).

[0132] 11 and 12, it is possible to introduce the EMLSR mode into the AP MLD 101, while quickly transitioning from the EMLSR mode to a normal mode such as the STR mode or the NSTR mode. Therefore, it is possible to quickly respond to changes in the throughput or transmission delay amount required by the non-AP MLD, while enabling power-saving operation in the AP MLD 101.

[0133] <Variation 1> The operations of S402 and S404 in FIG. 4 performed by the AP MLD 101 described in the above embodiment can be omitted. In this case, the AP MLD 101 starts operating in the EMLSR mode regardless of whether it receives a frame from the non-AP MLD 102 containing information indicating that EMLSR mode is permitted to be enabled. Furthermore, in this case, the non-AP MLD 102 can omit the operations of S801, S803, and S805. In this case, the non-AP MLD 102 determines that the AP MLD 101 will operate in the EMLSR mode based on the reception of a frame from the AP MLD 101 containing information indicating that the EMLSR mode is being enabled. Then, if the non-AP MLD 102 determines that the AP MLD 101 will operate in the EMLSR mode, it simply executes the process of S804.

[0134] In the above embodiment, the power supply to a circuit that is necessary for simultaneously exchanging frames over two links but that can be stopped without causing any problems in EMLSR mode is stopped. However, the power control method is not limited to this, and a more proactive power saving control can also be performed.

[0135] Here, the power state corresponding to the EMLSR mode is referred to as the first power state, and the power state corresponding to the normal mode is referred to as the second power state. In order to further reduce power consumption in the first power state, a general-purpose hardware processor such as a CPU constituting the control unit 202 can be controlled to operate in a power-saving mode. This will be specifically described using FIG. 13.

[0136] In the second modification, it is assumed that the control unit 202 is configured by a general-purpose hardware processor such as a CPU, and executes a control program to control the communication unit 206 such as a wireless chip. In other words, the control unit 202 includes a general-purpose hardware processor that controls communication in cooperation with the communication chip.

[0137] The instruction set architecture of this general-purpose hardware processor can be x64 architecture, ARM architecture, RISC-V architecture, etc. It may also be x86 architecture or MIPS architecture.

[0138] When the control unit 301 of the AP MLD 101 transitions the power state of the AP MLD 101 to the first power state, the control unit 301 changes the operation mode of the general-purpose hardware processor so that the AP MLD 101 operates in a power-saving state.

[0139] The change in the operating mode may be any mode that has the effect of causing clock gating and / or power gating within the general-purpose hardware processor.Furthermore, the operating mode may be changed so that general-purpose memories such as DRAMs (Dynamic Random Access Memory) operate in a power-saving state.

[0140] The effect of this will be explained as follows: When designing the AP MLD 101, a general-purpose hardware processor and general-purpose memory are appropriately selected that have the hardware capacity to process data without any problems, taking into consideration the load of data processing in normal modes such as STR mode and NSTR mode.

[0141] Therefore, compared to the normal mode, there is an abundance of processing capacity during periods 1100 and 1102 when the processing load is expected to be low. In this embodiment, the processing capacity of the general-purpose hardware processor and general-purpose memory can be intentionally reduced during periods 1100 and 1102 when the load is low, thereby reducing power consumption, thereby achieving further power savings. Therefore, power consumption during EMLSR mode operation can be reduced more than during normal mode operation such as STR or NSTR mode.

[0142] It is also possible to configure the system so that the first power state and the second power state are switched for each state constituting the EMLSR mode. Specifically, different power states can be used for the state in which the EMLSR link is listened to and the communication state in which communication is actually performed using the EMLSR link. For example, in this case, when listening for packets in the EMLSR mode, a first power state can be adopted in which the general-purpose hardware processor and general-purpose memory are operated in a power-saving state. On the other hand, in the communication state in which data communication is actually performed using the EMLSR link, a second power state can be adopted in which the general-purpose hardware processor and general-purpose memory are operated in a normal mode.

[0143] <Modification 3> In the above embodiment, the case where the non-AP MLD 102 is configured to start operating in EMLSR mode in S804 has been described. However, the non-AP MLD 102 may not start operating in EMLSR mode, but may simply start appropriate control so that it can communicate with the AP MLD 101 that has started operating in EMLSR mode. In other words, the non-AP MLD itself may be configured not to transition to EMLSR mode.

[0144] In this case, the processes in FIG. 10 used to explain the details of step S804 may be modified as follows. First, the process in FIG. 10 begins when the process in step S804 in this modified example is started. In S1006, the control unit 301, in cooperation with the other units, determines whether any frame has been received from the AP MLD 101, not limited to an initial control frame. At this time, the AP MLD 101 is operating in EMLSR mode and transmits frames only through one link, so the non-AP MLD 102 receives frames only through one link. If the non-AP MLD 102 determines that any frame has been received from the AP MLD 101, the process proceeds to S1004; if it does not determine that any frame has been received, the process proceeds to S1000. Furthermore, in S1004, the control unit 301 cooperates with each unit to transmit an initial control frame to the AP MLD 101. Note that if any frame has been received from the AP MLD in S1006, the process of transmitting the initial control frame to the AP MLD 101 is omitted. Next, the control unit 301 cooperates with each unit to execute data exchange with the AP MLD 101 over one link that has transmitted the initial control frame or one link that has received any frame. In other words, data exchange is performed while maintaining a state corresponding to the AP MLD 101 operating in EMLSR mode. When the control unit 301 determines that the series of data exchanges has been completed, it advances the process to S1000. The non-AP MLD 102 of this modified example, which does not start operation in the EMSLR mode, can simply repeat the receiving operation of the modified example without making the determination in S1005.

[0145] (Another embodiment 1) The disclosure of this embodiment also includes the following configuration.

[0146] (Configuration 1) An access point device that performs wireless communication based on the IEEE 802.11 standard, comprising: a determination means for determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is operating in EMLSR (enhanced multi-link single radio) mode; a communication control means for canceling the EMLSR mode and performing data communication with the station device when the determination means determines that a frame of the predetermined type has been received; and a transition means for transitioning to the EMLSR mode after data communication has been performed by the communication control means.

[0147] (Configuration 2) The communication device according to configuration 1, wherein the predetermined type of frame is an RTS (Request To Send) frame.

[0148] (Configuration 3) The communication device according to configuration 1, wherein the predetermined type of frame is an NDP (Null Data PPDU) frame.

[0149] (Configuration 4) The communication device according to configuration 1, wherein the predetermined type of frame is an EML (enhanced multi-link) Operating Mode Notification frame.

[0150] (Configuration 5) A station device that performs wireless communication based on the IEEE 802.11 standard, comprising: a communication control means that transmits a predetermined type of frame to an access point device to which the station device is connected, the access point device operating in EMLSR (enhanced multi-link single radio) mode; and the communication control means further comprises communication control means that, after transmitting the predetermined type of frame, performs data communication with the access point device that has released the EMLSR mode using reception of the predetermined type of frame as a trigger.

[0151] (Configuration 6) The station device according to configuration 5, wherein the predetermined type of frame is an RTS (Request To Send) frame.

[0152] (Configuration 7) The station device according to configuration 5, wherein the predetermined type of frame is an NDP (Null Data PPDU) frame.

[0153] (Configuration 8) The station device according to configuration 5, wherein the predetermined type of frame is an EML (enhanced multi-link) Operating Mode Notification frame.

[0154] (Configuration 9) An access point device that performs wireless communication based on the IEEE 802.11 standard, comprising: a determination means for determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is in a first power state and operating in EMLSR (enhanced multi-link single radio) mode; a communication control means for transitioning to a second power state and performing data communication with the station device after the determination means has determined that a frame of the predetermined type has been received; a control means for controlling the power state of the communication device to transition from the second power state to the first power state after data communication has been performed by the communication control means; the first power state is a power state that consumes less power than the second power state; and when transitioning the power state of the communication device to the first power state, the control means changes the operating mode of a general-purpose hardware processor that controls communication in cooperation with a communication chip so that the general-purpose hardware processor operates in a power-saving state.

[0155] (Configuration 10) The access point device according to Configuration 9, wherein the instruction set architecture of the general-purpose hardware processor is either an x64 architecture, an ARM architecture, or a RISC-V architecture.

[0156] (Configuration 11) The access point device according to configuration 9 or 10, wherein the change in the operation mode causes clock gating and / or power gating within the general-purpose hardware processor.

[0157] (Configuration 12) The access point device according to any one of Configurations 9 to 11, wherein the predetermined type of frame is an initial control frame.

[0158] (Configuration 13) A control method for an access point device that performs wireless communication based on the IEEE 802.11 standard, comprising: a determination step of determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is operating in EMLSR (enhanced multi-link single radio) mode; a communication control step of canceling the EMLSR mode and performing data communication with the station device when it is determined in the determination step that a frame of the predetermined type has been received; and a transition step of transitioning to the EMLSR mode after data communication has been performed in the communication control step.

[0159] (Configuration 14) A control method for a station device that performs wireless communication based on the IEEE 802.11 standard, comprising: a transmission control step of transmitting a predetermined type of frame to an access point device to which the station device is connected, the access point device operating in EMLSR (enhanced multi-link single radio) mode; and a communication control means for transmitting the predetermined type of frame and then performing data communication with the access point device that has released the EMLSR mode as a trigger upon receiving the predetermined type of frame.

[0160] (Configuration 15) A program for causing a computer to execute the control method according to configuration 13 or 14.

[0161] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0162] According to one aspect of the above embodiment or modification, it is possible to operate the AP MLD in a power-saving manner while quickly responding to changes in the throughput or transmission delay required by the non-AP MLD. In addition, as another aspect of the present invention, it is possible for the AP MLD to perform power-saving operation.

[0163] This application claims priority based on Japanese Patent Application No. 2023-131393, filed on August 10, 2023, the entire contents of which are incorporated herein by reference.

[0164] 101 AP MLD 102 non-AP MLD 206 Communication Department

Claims

1. An access point device that performs wireless communication based on the IEEE 802.11 standard, comprising: a determination means for determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is operating in EMLSR (enhanced multi-link single radio) mode; a communication control means for canceling the EMLSR mode and performing data communication with the station device when the determination means determines that a frame of the predetermined type has been received; and a transition means for transitioning to the EMLSR mode after data communication has been performed by the communication control means.

2. The communication device according to claim 1, wherein the predetermined type of frame is an RTS (Request To Send) frame.

3. The communication device according to claim 1, wherein the predetermined type of frame is a Null Data PPDU (NDP) frame.

4. The communication device according to claim 1, wherein the predetermined type of frame is an enhanced multi-link (EML) Operating Mode Notification frame.

5. A station device performing wireless communication based on the IEEE 802.11 standard, comprising: a communication control means for transmitting a predetermined type of frame to an access point device to which the station device is connected, the access point device operating in EMLSR (enhanced multi-link single radio) mode; and a communication control means for performing data communication with the access point device which has released the EMLSR mode after transmitting the predetermined type of frame, triggered by the reception of the predetermined type of frame.

6. The station device according to claim 5, wherein the predetermined type of frame is an RTS (Request To Send) frame.

7. The station device according to claim 5, wherein the predetermined type of frame is a Null Data PPDU (NDP) frame.

8. The station device according to claim 5, wherein the predetermined type of frame is an enhanced multi-link (EML) Operating Mode Notification frame.

9. An access point device performing wireless communication based on the IEEE 802.11 standard, comprising: a determination means for determining whether a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is in a first power state and operating in EMLSR (enhanced multi-link single radio) mode; a communication control means for transitioning to a second power state and performing data communication with the station device after the determination means has determined that the frame of the predetermined type has been received; a control means for controlling the transition of the power state of the communication device from the second power state to the first power state after data communication has been performed by the communication control means; the first power state is a power state that consumes less power than the second power state; and when transitioning the power state of the communication device to the first power state, the control means changes the operating mode of a general-purpose hardware processor that controls communication in cooperation with a communication chip so that the general-purpose hardware processor operates in a power-saving state.

10. The access point device according to claim 9, wherein the instruction set architecture of the general-purpose hardware processor is any one of the x64 architecture, the ARM architecture, and the RISC-V architecture.

11. The access point device according to claim 10, wherein the change in the operation mode causes clock gating and / or power gating within the general-purpose hardware processor.

12. The access point device according to claim 9, wherein the predetermined type of frame is an initial control frame.

13. A control method for an access point device that performs wireless communication based on the IEEE 802.11 standard, comprising: a determination step of determining whether or not a frame of a predetermined type has been received from a station device connected to the access point device when the access point device is operating in EMLSR (enhanced multi-link single radio) mode; a communication control step of canceling the EMLSR mode and performing data communication with the station device if it is determined in the determination step that a frame of the predetermined type has been received; and a transition step of transitioning to the EMLSR mode after data communication has been performed in the communication control step.

14. A method for controlling a station device that performs wireless communication based on the IEEE 802.11 standard, comprising: a transmission control step of transmitting a predetermined type of frame to an access point device to which the station device is connected, the access point device being operating in EMLSR (enhanced multi-link single radio) mode; and a communication control means for performing data communication with the access point device that has released the EMLSR mode after transmitting the predetermined type of frame, triggered by the reception of the predetermined type of frame.

15. A program for causing a computer to execute the control method according to claim 13 or 14.

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