Method for enhanced multi-link operation and corresponding wireless communication device

Abstract

Embodiments of the present invention provide an improved switching mechanism for a multi-link device, which can perform frame exchange using multiple spatial streams and deterministically and automatically switch to a listening mode for multiple EML-enabled links to improve throughput and reduce latency. Embodiments of the present invention are applicable to multi-link operations performed using multi-radio devices or single-radio devices.

Description

Technical Field

[0001] The present invention generally relates to the field of wireless communications, and more specifically, to a method for enhanced multi-link operation in a wireless network and a corresponding wireless communication device. Background Art

[0002] Modern electronic devices often use Wi-Fi to wirelessly send and receive data with other electronic devices, and many of these electronic devices are "dual band" devices, which include at least two wireless transceivers capable of operating in different frequency bands (e.g., 2.4 GHz, 5 GHz, and 6 GHz). In most cases, wireless devices can only communicate through one frequency band at a time. For example, old low-power devices (e.g., battery-powered devices) typically operate on the 2.4 GHz band. New devices and devices that require greater bandwidth typically operate on the 5 GHz band. The availability of the 6 GHz band is a recent advancement that can provide higher performance, lower latency, and faster data rates.

[0003] The use of a single frequency band may not meet the bandwidth or latency requirements of some devices. Therefore, some developing wireless communication methods increase the communication bandwidth by operating on multiple frequency bands simultaneously (technically referred to as link aggregation or multi-link operation). Advantageously, multi-link operation can provide higher network throughput and better network flexibility compared to traditional technologies for wireless communication.

[0004] For MLD devices operating with only a single radio, enhanced multi-link single radio operation (EML) can provide throughput enhancement and latency reduction similar to concurrent dual-radio MLD. EML operation enables wireless devices with a single radio to receive data using multiple channels / links. When a wireless device operates in EML mode with an AP that supports EML mode, the device can listen to these enabled links by keeping the attached wireless stations (STAs) corresponding to the enabled links in an awake state ("listening mode"). The listening operation may include performing a clear channel assessment (CCA), and receiving an initial control frame of a frame exchange sequence initiated by the AP MLD. The initial control frame of the frame exchange sequence is sent before any data frame exchange and is sent by the AP MLD to a wireless device operating in EML mode. The initial control frame is typically a MU-RTS trigger frame or a buffer status report poll (BSRP) trigger frame.

[0005] However, existing methods of multi-link operation in EML mode cannot accurately determine when the wireless device will switch to listening mode for the enabled multi-link, for example, after the frame exchange sequence is completed. Therefore, there is a need for an improved switching mechanism for multi-link operation to utilize available links and improve latency and throughput of EML operation. Summary of the invention

[0006] The following summary is illustrative only and is not intended to be limiting in any way. That is, the following overview is provided to introduce the concepts, highlights, benefits, and advantages of the novel and non-obvious technologies described herein. Selected embodiments are further described in the detailed description below. Therefore, the following summary is neither intended to identify the essential features of the claimed subject matter nor to be used to determine the scope of the claimed subject matter.

[0007] The embodiment of the present invention provides an improved switching mechanism for a multi-link device, which can perform frame exchange using multiple spatial streams and automatically switch to a listening mode on an EML-enabled link at a determined time (according to a predetermined rule) to improve throughput and reduce latency. The embodiment of the present invention is applicable to multi-link operations performed by a multi-radio device or a single-radio device.

[0008] In a first aspect, the present invention provides a method for enhanced multi-link operation, characterized in that the method is executed by a multi-link device MLD in a wireless network, and the method includes: performing a listening operation on multiple enhanced multi-link EML links of the wireless network; receiving an initial control frame from an AP corresponding to the first EML link in a wireless access point AP MLD through a first EML link of the multiple EML links; enabling reception on the first EML link using multiple spatial streams; performing frame exchange using the multiple spatial streams to receive data from the AP through the first EML link; and, after a switching delay time after the frame exchange ends, switching to the listening operation on the multiple EML links.

[0009] In some embodiments, the method further includes: performing multiple frame exchanges using the multiple spatial streams to receive data from the AP via the first EML link; and, in response to a frame most recently received from the AP and requiring an immediate response, ending the frame exchange with the AP by not sending a response frame to the AP on the first EML link.

[0010] In some embodiments, the method further includes: performing multiple frame exchanges using the multiple spatial streams to receive data from the AP via the first EML link; and, in response to a frame most recently received from the AP, ending the frame exchange with the AP by sending a response frame to the AP on the first EML link indicating a switch to the listening operation.

[0011] In some embodiments, the method also includes: performing multiple frame exchanges using the multiple spatial streams to receive data from the AP through the first EML link; and, when the medium is in an idle state after sending a response frame to the AP in response to a frame most recently received from the AP, ending the frame exchange with the AP after a timeout interval after sending the response frame, wherein the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a wireless frame, and aSlotTime is a predefined time unit.

[0012] In some embodiments, the method further includes: performing multiple frame exchanges using the multiple spatial streams to receive data from the AP through the first EML link; and, when the medium is in an idle state after receiving a frame that does not require an immediate response from the AP, ending the frame exchange with the AP after a timeout interval equal to aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a wireless frame, and aSlotTime refers to a predefined time unit.

[0013] In some embodiments, the frame exchange includes: receiving a frame including a duration field from the AP; and initializing a timer based on the duration field, wherein the timer begins counting down the frame.

[0014] In some embodiments, the method further comprises: ending the frame exchange in response to the value of the timer reaching zero.

[0015] In some embodiments, the method further includes clearing the timer when the medium is idle after a timeout interval after sending a response frame in response to a frame most recently received from the AP, wherein the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a wireless frame, and aSlotTime refers to a predefined time unit.

[0016] In some embodiments, the method further comprises: receiving a second frame from the AP indicating switching to the listening operation, wherein the switching to the listening operation of the plurality of EML links is performed in response to the second frame.

[0017] In a second aspect, the present invention provides a method for enhanced multi-link operation, characterized in that the method is performed by a multi-link device MLD in a wireless network, and the method includes: initiating a frame exchange with the STA by sending an initial control frame to the STA corresponding to the first EML link in the wireless station STA MLD on the first EML link among multiple enhanced multi-link EML links; and, in response to receiving an immediate response frame from the STA, performing another frame exchange using multiple spatial streams of the wireless network to send data to the STA through the first EML link.

[0018] In some embodiments, the method further includes: when no immediate response frame requested by the AP is received, sending a second initial control frame to the STA.

[0019] In a third aspect, the present invention provides a wireless communication device, characterized in that the wireless communication device includes a wireless transceiver and a processor, the wireless transceiver is used to communicate in a wireless network, and the processor is configured to: perform a listening operation on multiple enhanced multi-link EML links of the wireless network; receive an initial control frame from an AP corresponding to the first EML link in a wireless access point AP multi-link device MLD through a first EML link among the multiple EML links; enable reception on the first EML link using the multiple spatial streams; perform frame exchange using the multiple spatial streams to receive data from the AP through the first EML link; and, after a switching delay time after the frame exchange ends, switch to the listening operation on the multiple EML links.

[0020] In some embodiments, the processor may be further operable to: perform multiple frame exchanges using the multiple spatial streams to receive data from the AP via the first EML link; and, in response to a most recently received frame that requires an immediate response, end the frame exchange with the AP by not sending a response frame to the AP on the first EML link.

[0021] In some embodiments, the processor may be further operable to: perform multiple frame exchanges using the multiple spatial streams to receive data from the AP via the first EML link; and, in response to a frame most recently received from the AP, end the frame exchange with the AP by sending a response frame to the AP on the first EML link indicating a switch to the listening operation.

[0022] In some embodiments, the processor may be further operated to: perform multiple frame exchanges using the multiple spatial streams to receive data from the AP through the first EML link; and, when the medium is in an idle state after sending a response frame to the AP, end the frame exchange with the AP after a timeout interval after sending the response frame, wherein the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to the inter-frame interval, aRxPHYStartDelay refers to the start delay of receiving a wireless frame, and aSlotTime is a predefined time unit.

[0023] In some embodiments, the processor may be further operated to: perform multiple frame exchanges using the multiple spatial streams to receive data from the AP through the first EML link; and, when the medium is in an idle state after receiving a frame that does not require an immediate response from the AP, end the frame exchange with the AP after a timeout interval equal to aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to the inter-frame interval, aRxPHYStartDelay refers to the start delay of receiving a wireless frame, and aSlotTime refers to a predefined time unit.

[0024] In some embodiments, the frame exchange includes receiving a frame including a duration field from the AP.

[0025] In some embodiments, the processor is further operable to: initialize a timer based on the duration field, wherein the timer begins counting down a frame.

[0026] In some embodiments, the processor is further operable to: end the frame exchange in response to the value of the timer reaching zero.

[0027] In some embodiments, the processor may be further operated to: clear the timer after a timeout interval after sending a response frame in response to a frame most recently received from the AP, wherein the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a wireless frame, and aSlotTime refers to a predefined time unit.

[0028] Those skilled in the art will no doubt understand these and other objects of the present invention after reading the following detailed description of the preferred embodiments shown in the accompanying drawings. The detailed description will be given in the following embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention may be more fully understood by reading the following detailed description and by referring to the examples given in the accompanying drawings, in which:

[0030] Figure 1 A block diagram of an exemplary wireless network in which a single-radio STA MLD operating in EML mode performs multi-link operations is shown.

[0031] Figure 2 1 is a block diagram of an exemplary wireless network in which a single radio STA MLD operating in EML mode performs multi-link operations according to an embodiment of the present invention. The single radio STA MLD deterministically switches to a listening mode on an available link to reduce delay.

[0032] Figure 3 1 is a block diagram of an exemplary wireless network in which a single radio STA MLD operating in EML mode performs multi-link operations according to an embodiment of the present invention. The single radio STA MLD deterministically switches to a listening mode to reduce delay when a link is unavailable.

[0033] Figure 4 1 is a block diagram of an exemplary wireless network in which a single radio STA MLD operating in EML mode performs multi-link operations according to an embodiment of the present invention. The single radio STA MLD deterministically switches to a listening mode to reduce delay after its reception fails.

[0034] Figure 5 The present invention is a flowchart of an exemplary sequence of exemplary computer-implemented steps for a process in which a multi-link device in a wireless network performs downlink EML operations and automatically switches to a listening mode on an enabled wireless link according to an embodiment of the present invention.

[0035] Figure 6FIG. 1 is a block diagram of an exemplary computer system platform on which an embodiment of the present invention may be implemented according to an embodiment of the present invention.

[0036] In the following detailed description, for the purpose of illustration, many specific details are set forth so that those skilled in the art can more thoroughly understand the embodiments of the present invention. However, it is apparent that one or more embodiments may be implemented without these specific details, and different embodiments may be combined as needed, and should not be limited to the embodiments listed in the accompanying drawings. DETAILED DESCRIPTION

[0037] The following description is a preferred embodiment of the present invention, which is only used to illustrate the technical features of the present invention, and is not used to limit the scope of the present invention. Certain words are used throughout the specification and claims to refer to specific components. It should be understood by those skilled in the art that manufacturers may use different names to refer to the same components. Therefore, the present specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as a basis for distinction. The terms "component", "system" and "device" used in the present invention can be entities related to computers, wherein the computer can be hardware, software, or a combination of hardware and software. The terms "including" and "comprising" mentioned in the following description and claims are open-ended terms, so they should be interpreted as "including, but not limited to...". In addition, the term "coupled" means an indirect or direct electrical connection. Therefore, if a device is described as coupled to another device, it means that the device can be directly electrically connected to the other device, or indirectly electrically connected to the other device through other devices or connection means.

[0038] Reference will now be made in detail to several embodiments. Although the subject matter will be described in conjunction with alternative embodiments, it should be understood that they are not intended to limit the claimed subject matter to these embodiments. On the contrary, the claimed subject matter is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the claimed subject matter defined by the appended claims.

[0039] In addition, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will recognize that embodiments may be practiced without these specific details or their equivalents. In other cases, well-known methods, processes, components, and circuits are not described in detail to avoid unnecessarily obscuring aspects and features of the subject matter.

[0040] Portions of the following detailed description are presented and discussed in terms of methods. Although the drawings (e.g., Figure 5) discloses its steps and sequence, but these steps and sequence are exemplary. The embodiment is very suitable for executing various other steps or variations of the steps listed in the flowcharts of the drawings of this article, and executing in an order different from that depicted and described in this article.

[0041] Some parts of the detailed description are presented according to the process, steps, logic blocks, processing and other symbolic representations of the operations on data bits that can be performed on computer memory. These descriptions and representations are the means by which the technical personnel in the field of data processing use the essence of their work to convey to other technical personnel in the field most effectively. Here, steps, computer-executed steps, logic blocks, processes, etc. are generally considered to be the self-consistent sequence of steps or instructions that lead to the desired result. These steps are steps that require physical manipulation of physical quantities. Usually, although not necessarily, these quantities (quantities) take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared and otherwise manipulated in a computer system. Mainly for general purposes, it has been proven that it is convenient to refer to these signals as bits, values, components, symbols, characters, items, numbers, etc. sometimes.

[0042] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless otherwise expressly stated, as will be apparent from the following discussion, it should be understood that throughout the discussion, terms such as "access," "write," "include," "store," "transmit," "associate," "identify," "encode," etc., are used to refer to operations and processes of a computer system or similar electronic computing device that transform data represented as physical (electronic) quantities in the computer system's registers and memories into other similarly represented physical quantities in the computer system's memories or registers or other such information storage, transmission, or display devices.

[0043] Automatic multi-channel EML operation for multi-link devices

[0044] The embodiment of the present invention provides an improved enhanced multi-link (EML) operation for a multi-link device, which can use / utilize multiple spatial streams on an EML enabled link (enabled link, referring to a link that supports EML operation, also referred to as an "EML link", such as a first EML link, sometimes referred to as an "enabled link" in the present invention) to perform frame exchange and deterministically / automatically switch to a listening mode on multiple EML enabled links to improve throughput and reduce delay. The embodiment of the present invention is applicable to multi-link operations performed by a multi-radio device or a single-radio device. It can be understood that according to the number of different wireless signals received by the terminal at the same time, the terminal can be divided into a multi-radio (e.g., dual-radio) device and a single-radio device.

[0045] For ease of understanding and explanation, the embodiment of the present invention is described by taking a single radio device as an example, but the present invention should not be limited to this example scenario. According to a method for automatically switching to a listening mode on one or more EML channels, each station (STA) of a non-access point (AP) multi-link device (MLD) operating on an enhanced multi-link single radio operation (EML) channel listens to the corresponding channel using a 1x1 spatial stream to receive an initial control frame. When the AP MLD (access point multi-link device) obtains channel access rights on one of the EML (enhanced multi-link single radio operation) channels (e.g., the first channel), the AP MLD transmits an initial control frame on that channel (e.g., the first channel). The STA listening on the same channel receives the initial control frame and responsively enables multiple spatial streams to receive data on that channel (e.g., the first channel) (e.g., the STA switches all antennas to the channel receiving the initial control frame).

[0046] A wireless access point (AP) multi-link device (MLD) initiates frame exchange with a non-AP MLD (STA MLD) operating in EML mode by sending an initial control frame on one of a plurality of EML links (e.g., a first EML link) to a wireless station (STA, e.g., the STA corresponding to the first EML link in the STAMLD). After the non-AP MLD receives the initial control frame on one of the plurality of EML links, the non-AP MLD starts a timer (e.g., an E-timer) to track the duration of the frame exchange sequence initiated by the AP MLD. The timer may be initialized using the duration in the Duration / ID field of the initial control frame received from the AP of the AP MLD (e.g., the AP corresponding to the first EML link in the AP MLD). If the target STA fails to respond to the initial control frame (for example, due to detection of medium busy, due to reception of broadcast frames scheduled on other links of the EML link, etc.), the STA ends the frame exchange and switches to the listening operation on the EML link after the switching delay time. The timer is reset / cleared after a specific time interval after the end of the received initial control frame, for example, the specific time interval is aSIFSTime+aRxPHYStartDelay, where the variable aSIFSTime+aRxPHYStartDelay is defined by the capabilities of the wireless network. In the example of the present invention, aSIFSTime (a Short Inter Frame Time) refers to the inter-frame interval, such as a short inter-frame interval time, which generally refers to two inter-frame intervals in a frame exchange. aRxPHYStartDelay refers to the start delay of receiving a wireless frame, that is, the time from when the physical layer detects the beginning of a wireless signal to when it determines that it is a wireless signal. aSlotTime is a gap time, that is, a predefined time unit (such as fixed). This may occur, for example, when channel sensing indicates that the channel is busy, or when broadcast frame reception is scheduled on another EML link of the plurality of EML links.If the medium is idle within a timeout interval (e.g., aSIFSTime+aRxPHYStartDelay) after a physical layer protocol data unit (PPDU) sent by a STA of a non-AP MLD in response to receiving an initial control frame from an AP of an AP MLD ends, the STA ends the frame exchange and switches to a listening operation on the multiple EML links after a switching delay time. It can be understood that the switching delay time is a mode switching delay caused by a limitation of the device hardware. If the medium is idle within a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after a physical layer protocol data unit (PPDU) sent by a STA of a non-AP MLD in response to receiving a data frame (non-initial control frame) from an AP of an AP MLD ends, the STA ends the frame exchange and switches to a listening operation on the multiple EML links after a switching delay time. The timer is reset to zero (i.e., cleared). If the medium is clear after a response frame (which is in response to a frame other than the initial control frame) is received, the STA may also end the frame exchange and switch to / back to the listening operation on the multiple EML links.

[0047] The timer may start counting down from the end point of the received PPDU containing the frame, and may be reinitialized / updated using the duration of the duration / ID field in the non-initial control frame most recently received from the AP of the AP MLD that initiated the frame exchange. In response to the most recently received frame from the AP of the AP MLD, if the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the end of the PPDU sent by the STA of the non-AP MLD in response to receiving the PPDU, the timer maintains the current value and continues to count down. If the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the end of the PPDU containing the frame that does not require immediate acknowledgment is received from the AP of the AP MLD, the timer maintains the current value and continues to count down.

[0048] The AP MLD may indicate in a PPDU sent to a non-AP MLD STA in EML mode that it is requesting the STA to "switch to" listening operation, for example, because there is no more data to send or the TXOP is terminated early.

[0049] According to some embodiments, the non-AP MLD switches to a listening operation on the plurality of EML links after a switching delay time from the end of the frame exchange if any of the following conditions are met:

[0050] 1. The timer value in the non-AP MLD STA is zero;

[0051] 2. The non-AP MLD STA has sent a response to the PPDU indicating "Switch To" recently received from the AP of AP MLD;

[0052] 3. A non-AP MLD STA receives a PPDU from an AP MLD AP indicating "Switch to" and does not require an immediate response.

[0053] When an initial control frame or a non-initial control frame transmitted by the AP of the AP MLD fails (e.g., the AP fails to receive a response to the transmitted frame), if the AP of the AP MLD intends to continue transmitting to the same non-AP MLD (within an existing TXOP), the AP may start a frame exchange by transmitting another initial control frame to the STA of the non-AP MLD. If the initial control frame is transmitted on another link in the EML link, the AP may perform a backoff-off procedure before transmitting another initial control frame to the non-AP MLD. When the AP of the AP MLD transmits a non-initial PPDU within a TXOP without receiving a response frame from the STA, the AP may continue a frame exchange with the STA of the non-AP MLD (e.g., aSIFS+aSlotTime after the end of the frame transmitted by the AP) without transmitting an initial control frame to the non-AP MLD (within an existing TXOP). The AP may perform a backoff procedure as a continuation of the existing TXOP before continuing transmission. If the AP of the AP MLD performs a backoff procedure within its existing TXOP, it may not extend the TXNAV timer value. In this case, the non-AP MLD continues to count down.

[0054] Figure 1 An exemplary wireless network 100 is shown in which a single radio STA MLD operating in EML mode performs multi-link operations. AP MLD (Access Point Multi-Link Device) 105 includes concurrent dual radios, such as Figure 1 As shown, the concurrent dual radio frequency includes Radio 1 (110, also called the first radio frequency module) and Radio 2 (115, also called the second radio frequency module) operating on wireless channels Channel 1 (also called the first channel or simply ch1) and Channel 2 (also called the second channel or simply ch2) respectively. Figure 1As shown, Channel 1 is initially busy, and Channel 2 is initially available. AP MLD 105 sends an initial MU-RTS frame via Channel 2 (eg, Figure 1 120) to initiate a frame exchange (shown as "data" in the figure) with the non-AP (STA) MLD 120. In response, the non-AP MLD 120 (i.e., STA MLD) sends a CTS frame (marked as "C" in the figure) to the AP MLD 105 via Channel 2. Then, using Radio 2 115 of the AP MLD 105 and Radio 125 of the non-AP MLD 120, the AP MLD 105 transmits data to the non-AP MLD 120 in EML operation, wherein Radio 125 (a single radio module supported by the STA 120) is configured to operate in EML mode to perform frame exchanges on Channel 1 and Channel 2. When the non-AP MLD 120 participates in a frame exchange with the AP MLD on one link, the non-AP MLD 120 will not transmit or receive on any other link until the frame exchange sequence in EML mode ends.

[0055] The non-AP MLD 120 receives the PPDU sent using Channel 2 using multiple spatial streams (e.g., 2x2 spatial streams) after a short interframe space (SIFS) after the end of its response frame C. However, when the AP MLD 110 has stopped transmitting data on Channel 2 and Channel 1 becomes available to send a new initial control frame to start a new frame exchange, the non-AP MLD 120 may not receive the new initial frame on Channel 1 because the non-AP MLD 120 has not yet switched to the listening operation / mode on Channel 1 and Channel 2. In this example, the APMLD 110 does not know when the non-AP MLD 120 will switch to the listening mode on Channel 1 and Channel 2. Therefore, in order to reduce or prevent the non-AP MLD 120 from missing the reception of the initial control frame, it is advantageous that the non-AP MLD 120 deterministically switches to the listening mode on Channel 1 and Channel 2 after sending or receiving data in a multi-link EML operation on one channel (e.g., Channel 2), so that the available links can be effectively utilized.

[0056] Figure 2According to an embodiment of the present invention, an exemplary wireless network 200 is shown in which a single radio MLD operating in EML mode performs multi-link operation, which deterministically switches to a listening mode on a link enabled for EML mode to reduce latency and improve the utilization efficiency of the link enabled for EML mode. AP MLD 205 includes a concurrent dual radio with Radio 1 (210) and Radio 2 (215), wherein Radio 1 (210) and Radio 2 (215) operate on wireless channels Channel 1 and Channel 2, respectively. Figure 2 As shown, the AP MLD initiates a frame exchange sequence with the non-AP (STA) MLD 220 operating in the EML mode by sending an initial control frame (labeled "R" in the figure) to the STA of the non-AP MLD on one of the links enabled for the EML mode (e.g., Channel 2). The non-AP MLD 220 operating in the EML mode performs a listening operation using a 1x1 spatial stream on each wireless link (e.g., Channel 1 and Channel 2) (labeled "1x1 on ch1" and "1x1 on ch2" in the figure).

[0057] When an initial control frame is received from the AP of the AP MLD 205 on one of the EML enabled links for EML mode (e.g., Channel 1 and Channel 2 in the figure), the non-AP MLD 220 enables multiple spatial streams (2x2) on the link (e.g., Channel 2), and the STA of the non-AP MLD 220 operating on the link performs frame exchange using multiple spatial streams (2x2) after responding to the received initial control frame (as marked "2x2 on ch2" in the figure). After the frame exchange has ended and a switching delay time has passed, the non-AP MLD 220 switches to a listening operation on the EML enabled link (e.g., Channel 1, Channel 2, and / or other wireless links). In this way, when one of the EML enabled links is available, a new frame exchange can be initiated using the link to reduce delay and improve wireless performance.

[0058] Figure 3According to an embodiment of the present invention, an exemplary wireless network 300 is shown in which a single radio MLD operating in EML mode performs multi-link operations, and a STA of the single radio MLD deterministically switches to a listening mode when the STA ends the frame exchange by not sending a response frame in response to a received frame, for example, when the link is unavailable due to a busy channel; or when the STA has pre-scheduled data reception (for example, broadcast frame reception) on another link of the EML link. The AP MLD 305 includes a concurrent dual radio having Radio 1 (310) and Radio 2 (315), wherein Radio 1 (310) and Radio 2 (315) operate on wireless channels Channel 1 and Channel 2, respectively. As shown in FIG. Figure 3 As shown, AP MLD 305 initially detects that Channel 1 is busy. The AP of AP MLD obtains channel access rights on Channel 2 and sends an initial control frame (such as Figure 3 The STA of non-AP MLD 320 receives the initial control frame (such as Figure 3 ), the STA enables a link with multiple spatial streams (e.g., two receive antennas and two transmit antennas) to perform frame exchange.

[0059] Since the STA detects that Channel 2 is physically or virtually busy, the STA cannot respond to the initial control frame. Therefore, in order to prevent missing a new initial control frame, the non-AP MLD 320 switches to the listening operation on the above-mentioned multiple EML-enabled links after a preset time interval (e.g., aSIFSTime+aRxPHYStartDelay or aSIFSTime) and a switching delay time after the end of the initial control frame. In this way, the switching to the listening mode on the multiple EML-enabled links is determined. Therefore, the non-AP MLD 320 can then receive the control frame on Channel 1 and respond with a response frame to start frame exchange, and then receive data on Channel 1 using 2x2 spatial streams in EML mode. After the frame exchange is completed, when Channel 2 becomes available, the process can be performed again to perform EML operation using 2x2 spatial streams on Channel 2. The non-AP MLD 320 switches to the listening operation on multiple EML links after the frame exchange is completed.

[0060] Figure 4According to an embodiment of the present invention, an exemplary wireless network 400 is shown in which a single radio MLD operating in EML mode performs multi-link operation, and deterministically switches to a listening mode after a STA reception failure of the single radio MLD to reduce delay and improve the utilization efficiency of multiple links enabled for EML mode. AP MLD 405 includes a concurrent dual radio including Radio 1 (410) and Radio 2 (415), wherein Radio 1 (410) and Radio 2 (415) operate on wireless channels Channel 1 and Channel 2, respectively. Figure 4 As shown, the STA of non-AP MLD 420 receives the initial control frame (marked R in the figure) from the AP of AP MLD 405 on the EML-enabled link (such as Channel 2). Therefore, the STA of non-AP MLD 420 enables the link with 2x2 spatial streams on Channel 2 to perform frame exchange. However, in some cases, the STA of non-AP MLD 420 may not successfully receive the frame sent by the AP after responding to the initial control frame (such as Figure 4 Therefore, after a preset time interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay or aSIFSTime+aRxPHYStartDelay) and a switching delay time have passed after the response transmission to the initial control frame ends, the non-AP MLD 420 switches to a listening operation on an EML-enabled link (e.g., Channel 1, Channel 2, and / or other wireless links). In this way, when the STA deterministically switches to the listening mode, delay can be advantageously reduced by utilizing available links.

[0061] In order to perform uplink (UL) transmission, the non-AP MLD operating in EML mode may initiate a frame exchange with the AP of the AP MLD on the EML enabled link, and the AP of the AP MLD starts a timer, the duration of which is set to indicate the duration information of the frame exchange sequence initiated by the non-AP MLD. For example, the timer may be initialized with the duration specified in the Duration / ID field of the frame most recently received from the STA of the non-AP MLD that initiated the frame exchange. If the medium is idle for a timeout interval after the AP of the AP MLD transmits a PPDU as a response to an initial frame received from the STA of the non-AP MLD, the timer in the AP of the AP MLD will be reset to 0.

[0062] The timer in the AP of the AP MLD starts counting down from the end of reception of the PPDU containing the above frame, and reinitializes / updates the timer using the duration specified by the Duration / ID field in the non-initial frame most recently received from the non-AP MLD STA that initiated the frame exchange. If the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the end of a PPDU transmitted by the AP of the AP MLD (in response to the most recent frame received from the non-AP MLD STA), the timer maintains the current value and continues to count down. If the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the end of a PPDU containing a frame that does not require immediate acknowledgment received from a non-AP MLD STA, the timer maintains the current value and continues to count down.

[0063] A non-AP MLD in EML mode may indicate "switching back" to listening mode in a PPDU sent to the AP of the AP MLD, for example, when there is no more data to send or the TXOP is terminated early. In addition, a non-AP MLD may switch to listening operation after a switching delay time if any of the following conditions are met:

[0064] 1. The value of the TXNAV timer is zero;

[0065] 2. After the initial PPDU transmitted by the non-AP MLD STA is completed, the medium is idle for a timeout interval;

[0066] 3. The non-AP MLD STA has indicated "switching to" listening mode in the most recently sent PPDU that does not require an immediate response;

[0067] 4. The non-AP MLD STA receives the solicited response to the most recently sent PPDU indicating "switch to".

[0068] The AP MLD may invoke a new fallback and initiate a frame exchange with the non-AP MLD operating in EML mode on one of the enabled links after the switch delay time indicated by the non-AP MLD if any of the following conditions are met:

[0069] 1. The value of the timer in the AP of AP MLD is zero;

[0070] 2. The AP of AP MLD has sent a response to a PPDU recently received from a STA of non-AP MLD indicating "Switch To";

[0071] 3. The AP of AP MLD has received a PPDU from a STA of non-AP MLD indicating "switching to" and does not require an immediate response.

[0072] Figure 5 1 is a flowchart of an exemplary sequence of computer-implemented steps for performing downlink (DL) EML operations on an enabled wireless link and automatically switching to a listening mode according to an embodiment of the present invention. Some steps of the process can be performed by a multi-link non-AP having a single radio but operating on multiple spatial streams (e.g., 2x2).

[0073] In step 505, the AP MLD operating in the EML mode sends an initial control frame (e.g., MU-RTS frame) to the non-AP MLD via a first wireless channel (e.g., Channel 2) in the wireless network. The initial control frame includes a duration / ID field, which may indicate the duration of the frame exchange sequence.

[0074] In step 510, the non-AP MLD operating in the EML mode performs a listening operation using a 1x1 spatial stream on a plurality of wireless channels (e.g., a plurality of EML-enabled links) enabled for EML operation (supporting EML operation). The STA of the non-AP MLD receives an initial control frame on a first wireless channel and enables reception of frames using a plurality of spatial streams after sending a response frame in response to the initial control frame. After a switching delay time at the end of the frame exchange, the non-AP MLD switches to a listening operation on an EML-enabled link (a link enabled for EML operation).

[0075] In step 515, the STA of the non-AP MLD sends a response frame (eg, a CTS frame) to the AP MLD and enables 2x2 spatial streams on the first wireless channel. The non-AP MLD stops sending or receiving data on other EML-enabled links.

[0076] In step 520, the STA of the non-AP MLD performs a frame exchange sequence to wirelessly receive data from the AP MLD using 2x2 spatial streams on the first wireless channel. For example, the frame exchange may include receiving a PPDU. If the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the STA of the non-AP MLD has finished sending a PPDU in response to a frame recently received from the AP of the AP MLD, the STA ends the frame exchange. After the frame exchange ends, the timer maintains the current value and continues to count down. If the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the PPDU containing a frame that does not require immediate acknowledgment received from the AP of the AP MLD ends, the STA ends the frame exchange. The timer maintains the current value and continues to count down.

[0077] In step 525, the STA of the non-AP MLD switches to the listening operation on the multiple wireless channels (i.e., multiple EML links) after the frame exchange is completed. Step 525 may include: when the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the STA of the non-AP MLD sends a response to the most recently received PPDU, or when the medium is idle for a timeout interval (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) after the STA of the non-AP MLD receives a PPDU that does not require an immediate response, or the STA of the non-AP MLD has sent a response to the PPDU indicating "switched to" recently received from the AP of the AP MLD, or the STA of the non-AP MLD has received a PPDU indicating "switched to" and does not require an immediate response from the AP of the AP MLD, the STA of the non-AP MLD switches to the listening operation on the enabled wireless link after the switching delay time. For example, the AP MLD may indicate "switched to" in the PPDU sent to the STA of the non-AP MLD in the EML mode.

[0078] Exemplary Computer Control System

[0079] Figure 6An exemplary wireless device (also described as a wireless communication device) 600 on which an embodiment of the present invention can be implemented is shown. Embodiments of the present invention relate to a wireless device capable of automatically switching channels in a wireless network to perform EML operations according to an embodiment of the present invention. The following discussion describes such an exemplary electronic system or computer system, which can be used as a platform for implementing embodiments of the present invention. For example, the exemplary computer system can be a wireless access point (AP) or a wireless station (STA).

[0080] The wireless device 600 can deterministically switch to a listening mode on an EML-enabled link after performing a frame exchange sequence using the EML-enabled link to effectively receive data from another multi-link device in a wireless network. The wireless device 600 may include a single radio operating on multiple spatial streams (e.g., 2x2). The wireless device 600 includes a processor 605, which is used to run software applications and an optional operating system. The memory 610 may include a read-only memory and / or a random access memory, for example, to store applications and data (e.g., a table of index values) for use by the processor 605 and data received or sent by a radio frequency module (also referred to as a wireless transceiver) 615. The radio frequency module 615 can communicate with other electronic devices through a wireless network (e.g., WLAN) using multiple spatial streams (e.g., multiple antennas), and is typically operated according to IEEE standards (e.g., IEEE 802.11ax, IEEE 802.11ay, IEEE 802.11be, etc.), but the present invention is not limited to this.

[0081] The use of ordinal terms such as "first", "second", "third", etc. in the claims to modify claim elements does not in itself indicate any priority, precedence or order of one claim element relative to another claim element, or a temporal order of performing method actions, but is merely used as a marker to distinguish one claim element with the same name from another element with the same name using ordinal numbers.

[0082] Although the present invention has been described by way of example and in terms of preferred embodiments, it should be understood that the present invention is not limited to the disclosed embodiments. Instead, it is intended to cover various modifications and similar structures (as will be apparent to those skilled in the art), for example, combinations or replacements of different features in different embodiments. Therefore, the scope of the appended claims should be given the broadest interpretation to cover all such modifications and similar structures.

Claims

1. A method for enhanced multi-link operation, characterized in that: The method is performed by a multi-link device MLD in a wireless network, and the method includes: Performing a listening operation on a plurality of enhanced multi-link (EML) links of the wireless network; receiving an initial control frame from an AP corresponding to the first EML link among the wireless access points AP MLD through a first EML link of the plurality of EML links; enabling reception on the first EML link utilizing multiple spatial streams; performing frame exchange using the plurality of spatial streams to receive data from the AP through the first EML link; and, After a switching delay time after the frame exchange is completed, switching to the listening operation on the multiple EML links; wherein, when the medium is in an idle state after sending a response frame to the AP in response to a frame most recently received from the AP, the frame exchange with the AP is terminated after a timeout interval after sending the response frame; or, when the medium is in an idle state after receiving a frame from the AP that does not require an immediate response, the frame exchange with the AP is terminated after the timeout interval; The timeout interval is equal to aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a radio frame, and aSlotTime is a predefined time unit.

2. The method according to claim 1, characterized in that The method further includes: receiving another initial control frame from an AP corresponding to any one of the EML links in the AP MLD through any one of the multiple EML links; and, In response to the other initial control frame most recently received from the AP, do not send a response frame to the AP on any of the EML links and switch to the listening operation on the multiple EML links after a preset time interval and the switching delay time after the end of receiving the other initial control frame, wherein the preset time interval is aSIFSTime+aRxPHYStartDelay or aSIFSTime.

3. The method according to claim 1, characterized in that The method further includes: performing a plurality of frame exchanges using the plurality of spatial streams to receive data from the AP through the first EML link; and, In response to a first frame received from the AP for requesting the STA to switch to the listening operation, frame exchange with the AP is ended by sending a response frame indicating switching to the listening operation to the AP over the first EML link.

4. The method according to claim 1, characterized in that The frame exchange includes: receiving a frame including a duration field from the AP; and, A timer is initialized according to the duration field, wherein the timer starts counting down the frame.

5. The method according to claim 4, characterized in that The method also includes ending the frame exchange in response to the value of the timer reaching zero.

6. The method according to claim 4, characterized in that The method further includes: The timer is cleared when the medium is idle after a timeout interval after sending a response frame in response to the most recently received frame from the AP, where the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, where aSIFSTime refers to the inter-frame space, aRxPHYStartDelay refers to the start delay for receiving a radio frame, and aSlotTime refers to a predefined time unit.

7. The method according to claim 1, characterized in that The method further includes: A second frame indicating switching to the listening operation is received from the AP, wherein the switching to the listening operation for the plurality of EML links is performed in response to the second frame.

8. A method for enhanced multi-link operation, characterized in that: The method is performed by a multi-link device MLD in a wireless network, and the method includes: Initiating frame exchange with a STA in the wireless station STA MLD corresponding to the first EML link by sending an initial control frame on a first EML link in a plurality of enhanced multi-link EML links; and, In response to receiving the immediate response frame from the STA, performing another frame exchange using a plurality of spatial streams of the wireless network to send data to the STA over the first EML link; When no immediate response frame requested by the AP is received, a second initial control frame is sent to the STA.

9. A wireless communication device, characterized in that: The wireless communication device includes a wireless transceiver and a processor, the wireless transceiver is used to communicate in a wireless network, and the processor is configured to: Performing a listening operation on a plurality of enhanced multi-link (EML) links of the wireless network; Receiving an initial control frame from an AP corresponding to the first EML link in the wireless access point AP multi-link device MLD through a first EML link among the multiple EML links; enabling reception on the first EML link utilizing multiple spatial streams; performing frame exchange using the plurality of spatial streams to receive data from the AP through the first EML link; as well as, After a switching delay time after the frame exchange is completed, switching to the listening operation on the multiple EML links; wherein, when the medium is in an idle state after sending a response frame to the AP in response to a frame most recently received from the AP, the frame exchange with the AP is terminated after a timeout interval after sending the response frame; or, when the medium is in an idle state after receiving a frame from the AP that does not require an immediate response, the frame exchange with the AP is terminated after the timeout interval; The timeout interval is equal to aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a radio frame, and aSlotTime is a predefined time unit.

10. The wireless communication device according to claim 9, wherein: The processor is further operable to: receiving another initial control frame from an AP corresponding to any EML link in the AP MLD through any EML link of the plurality of EML links; as well as, In response to the other initial control frame most recently received, do not send a response frame to the AP on any of the EML links and switch to the listening operation on the multiple EML links after a preset time interval and the switching delay time after the end of receiving the other initial control frame, wherein the preset time interval is aSIFSTime+aRxPHYStartDelay or aSIFSTime.

11. The wireless communication device according to claim 9, wherein: The processor is further operable to: performing a plurality of frame exchanges using the plurality of spatial streams to receive data from the AP through the first EML link; and, In response to a first frame received from the AP for requesting the STA to switch to the listening operation, frame exchange with the AP is ended by sending a response frame indicating switching to the listening operation to the AP over the first EML link.

12. The wireless communication device according to claim 9, wherein: The frame exchange includes: A frame including a duration field is received from the AP.

13. The wireless communication device according to claim 12, wherein: The processor is further operable to initialize a timer based on the duration field, wherein the timer begins counting down a frame.

14. The wireless communication device according to claim 13, wherein: The processor is further operable to end the frame exchange in response to the value of the timer reaching zero.

15. The wireless communication device according to claim 13, wherein: The processor may be further operated to: clear the timer after a timeout interval after sending a response frame in response to a frame most recently received from the AP, wherein the timeout interval is equal to aSIFSTime+aRxPHYStartDelay or aSIFSTime+aslotTime+aRxPHYStartDelay, wherein aSIFSTime refers to an inter-frame interval, aRxPHYStartDelay refers to a start delay for receiving a wireless frame, and aSlotTime refers to a predefined time unit.

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