CN113904700B

CN113904700B - Wi-Fi multi-link equipment and wireless communication method adopted by same

Info

Publication number: CN113904700B
Application number: CN202110757475.5A
Authority: CN
Inventors: 徐建芳; 张正义; 谢弘道; 石镕豪
Original assignee: MediaTek Inc
Current assignee: MediaTek Inc
Priority date: 2020-07-07
Filing date: 2021-07-05
Publication date: 2023-02-07
Anticipated expiration: 2041-07-05
Also published as: CN113904700A

Abstract

The invention provides Wi-Fi multilink equipment and a communication method adopted by the same, which can dynamically change the operation mode parameters of the Wi-Fi multilink equipment. The invention provides a Wi-Fi multi-link device, which can comprise: a Transmit (TX) circuit; a Receive (RX) circuit; and a control circuit for controlling the RX circuit to receive a first frame under an operation mode parameter having a first setting, controlling the TX circuit to transmit a second frame in response to the first frame under the operation mode parameter having the first setting, and after the second frame is transmitted, controlling the RX circuit to receive at least one physical layer protocol data unit (PPDU) under the operation mode parameter having a second setting, wherein the second setting is different from the first setting.

Description

Wi-Fi multi-link device and wireless communication method adopted by same

Technical Field

The present invention relates to Wireless communications, and more particularly, to a Wireless Fidelity (Wi-Fi) Multi-Link Device (MLD) with dynamic mode switching and related methods.

Background

In Wi-Fi multi-link operation, there are multiple links (links) between two Wi-Fi MLDs (including one Access Point (AP) and one non-AP Station (STA)), which occupy different Radio-Frequency (RF) bands. One Wi-Fi MLD can independently perform Channel Access (e.g., enhanced Distributed Channel Access (EDCA)) over multiple wireless links, respectively. In particular, these wireless links may operate independently to increase overall throughput (throughput) and/or improve connection stability. For example, a Wi-Fi MLD may have a spatial stream (spatial stream) specified on a wireless link. The performance of the wireless link may be improved if the wireless link may use more resources to transmit or receive within a particular time period. Therefore, an innovative design capable of dynamically changing Wi-Fi MLD operating mode parameters (operation mode parameters) is needed.

Disclosure of Invention

The invention provides Wi-Fi multilink equipment and a communication method adopted by the same, which can dynamically change the operation mode parameters of the Wi-Fi multilink equipment.

The invention provides a Wi-Fi multilink device, which can comprise: transmit (TX) circuitry; a Receive (RX) circuit; and a control circuit for controlling the RX circuit to receive a first frame under an operation mode parameter having a first setting, controlling the TX circuit to transmit a second frame in response to the first frame under the operation mode parameter having the first setting, and after the second frame is transmitted, controlling the RX circuit to receive at least one physical layer protocol data unit (PPDU) under the operation mode parameter having a second setting, wherein the second setting is different from the first setting.

Another Wi-Fi multi-link device provided by the present invention may comprise: transmit (TX) circuitry; a Receive (RX) circuit; and control circuitry to control the TX circuitry to transmit a first frame under operating mode parameters having a first setting, to control the RX circuitry to receive a second frame in response to the first frame under the operating mode parameters having the first setting, and to control the TX circuitry to transmit at least one physical layer protocol data unit (PPDU) under operating mode parameters having a second setting after receiving the second frame, wherein the second setting is different from the first setting.

The invention provides a wireless communication method adopted by Wi-Fi multilink equipment, which comprises the following steps: controlling a Receive (RX) circuit to receive a first frame at an operating mode parameter having a first setting; control Transmit (TX) circuitry to transmit a second frame in response to the first frame under the operating mode parameter with the first setting; after the second frame transmission, controlling the RX circuitry to receive at least one physical layer protocol data unit (PPDU) in an operating mode parameter having a second setting, wherein the second setting is different from the first setting.

The invention provides another wireless communication method adopted by Wi-Fi multilink equipment, which comprises the following steps: control the TX circuitry to transmit a first frame at an operating mode parameter having a first setting; control the RX circuitry to receive a second frame in response to the first frame at the operating mode parameter with the first setting; and after receiving the second frame, controlling the TX circuitry to transmit at least one PPDU at an operating mode parameter having a second setting, wherein the second setting is different from the first setting.

The present invention can dynamically change the operation mode parameters of the Wi-Fi multi-link device by implementing the above-described embodiments, for example, from transmitting/receiving frames under the operation mode parameters having the first setting to transmitting/receiving frames under the operation mode parameters having the second setting.

Drawings

Fig. 1 is a diagram illustrating a wireless fidelity (Wi-Fi) communication system according to an embodiment of the present invention.

Fig. 2 is a diagram illustrating a first dynamic operating mode switching scenario according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a second dynamic operating mode switching scenario according to an embodiment of the present invention.

Fig. 4 is a diagram illustrating a third dynamic operating mode switching scenario according to an embodiment of the present invention.

Fig. 5 is a diagram illustrating a fourth dynamic operation mode switching scenario according to an embodiment of the present invention.

Fig. 6 is a diagram illustrating a fifth dynamic operation mode switching scenario according to an embodiment of the present invention.

Fig. 7 is a diagram illustrating a sixth dynamic operation mode switching scenario according to an embodiment of the present invention.

Fig. 8 is a diagram illustrating a seventh dynamic operating mode switching scenario according to an embodiment of the present invention.

Fig. 9 is a diagram illustrating additional signaling provided by channel quality indicator feedback according to an embodiment of the present invention.

FIG. 10 is a schematic diagram of an alternative design implemented based on the dynamic operating mode switching scenario shown in FIG. 2.

FIG. 11 is a schematic diagram of an alternative design implemented based on the dynamic operating mode switching scenario shown in FIG. 3.

FIG. 12 is a schematic diagram of an alternative design implemented based on the dynamic operating mode switching scenario shown in FIG. 4.

FIG. 13 is a schematic diagram of an alternative design implemented based on the dynamic operating mode switching scenario shown in FIG. 7.

FIG. 14 is a schematic diagram of an alternative design implemented based on the dynamic operating mode switching scenario shown in FIG. 8.

Detailed Description

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. The present specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, within which a person skilled in the art can solve the technical problem to substantially achieve the technical result. Furthermore, the term "coupled" is intended to include any direct or indirect electrical connection. Thus, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. The following is a description of the best mode contemplated for carrying out the present invention, and is intended to illustrate the spirit of the invention and not to limit the scope of the invention, which is defined by the claims.

The following description is of the best embodiments contemplated by the present invention. The description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention should be determined with reference to the claims that follow.

Fig. 1 is a diagram illustrating a wireless fidelity (Wi-Fi) communication system according to an embodiment of the present invention. The Wi-Fi communication system 100 includes a plurality of Wi-Fi multi-link devices (MLDs) 102 and 104, which include an Access Point (AP) and a non-AP Station (STA). For example, the Wi-Fi MLD104 can be an AP, while the Wi-Fi MLD 102 can be a non-AP STA. For simplicity, only two Wi-Fi MLDs are shown in FIG. 1. In practice, the Wi-Fi communication system 100 allows for having more than two Wi-Fi MLDs, which include one AP and more than one non-AP STA located in the same Basic Service Set (BSS). By way of example and not limitation, both Wi-

Fi MLDs

102 and 104 can conform to the IEEE 802.11be standard.

As shown in fig. 1, the Wi-Fi MLD 102 includes a processor 112, a memory 114, a control circuit 116, a Receive (RX) circuit 118, a Transmit (TX) circuit 120, and a plurality of antennas 122. The memory 114 is used to store program codes. The processor 112 is used to load and execute program code to manage the Wi-Fi MLD 102. The control circuit 116 is used to control wireless communications with the Wi-Fi MLD 104. When the Wi-Fi MLD 102 is a non-AP STA and the Wi-Fi MLD104 is an AP, the control circuit 116 controls the TX circuit 120 to process Uplink (UL) communications (traffic) between the AP and the non-AP STA and controls the RX circuit 118 to process Downlink (DL) communications between the AP and the non-AP STA. Due to the inherent characteristics of Wi-Fi MLD 102, TX circuit 120 includes multiple TX chains (TX chains), while RX circuit 118 includes multiple RX chains (RX chains). In this embodiment, the Wi-Fi MLD 102 is equipped with dynamic operating mode switching functionality.

For downlink communications between the AP and the non-AP STA, the control circuit 116 is to control the RX circuit 118 to receive a first frame under an operation mode parameter having a first setting (e.g., a default setting), control the TX circuit 120 to transmit a second frame in response to the first frame under the operation mode parameter having the first setting, and control the RX circuit 118 to receive at least one DL Physical layer Protocol Data Unit (PPDU) under an operation mode parameter having a second setting (e.g., a maximum setting or a non-default setting) for a remaining period of a transmission opportunity (TXOP) after transmitting the second frame, wherein the second setting is different from the first setting. Furthermore, the control circuit 116 is also configured to control the RX circuit 118 to resume (resume) the operating mode parameter having the first setting (e.g., the default setting) at the end of the TXOP.

In one exemplary mode switch design, the first frame may be a Request To Send (RTS) frame, the second frame may be a Clear To Send (CTS) frame in response To the RTS frame, where the RTS frame does not carry any operating mode parameter change indication and the CTS frame may or may not carry an operating mode parameter change indication specifying use of the second setting. When the CTS frame does not carry any operation mode parameter change indication, the CTS frame may serve as an indication indicating that the operation mode parameter maximum setting is used (i.e., second setting = maximum setting).

In another exemplary mode switch design, the first frame may be an RTS frame and the second frame may be a CTS frame in response to the RTS frame, where the CTS frame does not carry any operating mode parameter change indication and the RTS frame may or may not carry an operating mode parameter change indication specifying use of the second setting. When the RTS frame does not carry any operation mode parameter change indication, the RTS frame may serve as an indication indicating that the operation mode parameter maximum setting is used (i.e., second setting = maximum setting).

In yet another mode switch design example, the first Frame may be a query Frame (inquiry Frame) sent after the RTS/CTS handshake (handshaking) is completed, and the second Frame may be a Response Frame (RF) in Response to the query Frame, where the Response Frame is specifically designed to carry an indication of a change in operating mode parameters specifying use of a second setting (e.g., a maximum setting or a non-default setting).

For uplink communications between the AP and the non-AP STA, the control circuitry 116 is to control the TX circuitry 120 to transmit a first frame under operating mode parameters having a first setting (e.g., a default setting), control the RX circuitry 118 to receive a second frame in response to the first frame under operating mode parameters having the first setting, and control the TX circuitry 120 to transmit at least one UL PPDU under operating mode parameters having a second setting (e.g., a maximum setting or a non-default setting) for a remaining period of the TXOP after receiving the second frame, wherein the second setting is different from the first setting. Furthermore, the control circuitry 116 is also configured to control the TX circuitry 120 to resume operating mode parameters having a first setting (e.g., a default setting) at the end of the TXOP.

The Wi-Fi MLD 102 may have different operating modes on each link established between the Wi-

Fi MLDs

102 and 104. In some embodiments of the present invention, the operation mode parameter allowing dynamic switching may be at least one of a Number of Spatial Streams (NSS), a bandwidth, a decoding capability (e.g., a Modulation and Coding Scheme (MCS)), a maximum Media Access Control Protocol Data Unit (MPDU) length, a maximum aggregated Media Access Control Service Data Unit (a-MSDU) length, or a maximum aggregated Media Access Control Protocol Data Unit (a-MPDU) length index. For example, a default bandwidth may be set to 80 megahertz (MHz) and a maximum bandwidth may be set to 160MHz. As another example, the default decoding capability may cover only MCS0-MCS3, and the maximum decoding capability may cover all MCSs. As another example, the default maximum MPDU length on each link may be set to 8K, and the maximum MPDU length may be set to 11K.

To better understand the technical features of the proposed dynamic operation mode switching scheme, several examples are provided below.

Fig. 2 is a diagram illustrating a first dynamic operating mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set a default Receive (RX) NSS =1 and a maximum RX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen to a channel (channel). Control circuitry 116 controls RX circuitry 118 to receive an RTS frame from Wi-Fi MLD (which is an AP) 104, where the TXOP is initialized by sending the RTS frame. RX circuitry 118 receives an RTS frame on a link, and control circuitry 116 controls TX circuitry 120 to respond with a CTS frame on the same link, where the RTS/CTS mechanism requires a TXOP for frame exchange. Where the RTS frame is received based on a default operating mode parameter (e.g., RX NSS = 1). In this embodiment, the CTS frame carries an operation mode parameter change indication IND designating use of RX NSS = 2. In other words, wi-Fi MLD 102 will control RX circuit 118 to switch another RX chain (RX chain) to that link for enhanced RX NSS capability. After the CTS frame is sent by TX circuitry 120, control circuitry 116 controls RX circuitry 118 to operate under the changed operating mode parameters (e.g., RX NSS = 2) and other unchanged parameters, receiving one or more DL PPDUs on the link for the remainder of the TXOP. Therefore, the DL PPDU may be received through RX NSS =2 for the remaining period of the TXOP. At the end of the TXOP, control circuit 116 controls RX circuitry 118 to restore default operating mode parameters (e.g., RX NSS = 1) on the link. It is noted that if the CTS frame does not carry any operation mode parameter change indication, the maximum setting is inferred from such CTS frame (e.g. RX NSS = 4).

Fig. 3 is a diagram illustrating a second dynamic operation mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set default RX NSS =1 and maximum RX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen for channels. Control circuitry 116 controls RX circuitry 118 to receive an RTS frame from Wi-Fi MLD (which is the AP) 104, where the RTS frame is sent to initialize the TXOP. RX circuitry 118 receives an RTS frame on a link, and control circuitry 116 controls TX circuitry 120 to respond with a CTS frame on the same link, where the RTS/CTS mechanism requires a TXOP for frame exchange. After the TX circuitry 120 sends the CTS frame, the RX circuitry 118 receives a query frame sent from the Wi-Fi MLD (which is the AP) 104, where the query frame is used to query for possible operational mode changes for a subsequent time period of the TXOP on the link. After RX circuitry 118 receives the inquiry frame, TX circuitry 120 returns a response frame. Both RTS frames and query frames are received based on default operating mode parameters (e.g., RX NSS = 1). In this embodiment, the response frame carries an operation mode parameter change indication IND specifying use of RX NSS =4. In other words, wi-Fi MLD 102 will control RX circuitry 118 to switch the other RX chain (RX chain) to that link for achieving its maximum RX NSS capability. After TX circuitry 120 transmits the response frame, control circuitry 116 controls RX circuitry 118 to operate at the changed operating mode parameters (e.g., RX NSS = 4) and other unchanged parameters and to receive one or more DL PPDUs on the link for the remainder of the TXOP. Therefore, the DL PPDU may be received through RX NSS =4 for the remaining period of the TXOP. At the end of the TXOP, control circuit 116 controls RX circuitry 118 to restore default operating mode parameters (e.g., RX NSS = 1) on the link.

FIG. 4 is a diagram illustrating a third dynamic operating mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set a default Bandwidth (BW) =80MHz, and a maximum bandwidth =160MHz. On each link, the Wi-Fi MLD 102 operates in a default mode to listen to the channel. Control circuitry 116 controls RX circuitry 118 to receive an RTS frame from Wi-Fi MLD (i.e., AP) 104, where the RTS frame is sent to initialize the TXOP, while the RTS frame carries an operational mode parameter change indication IND indicating that BW =160MHz is used. After RX circuitry 118 receives an RTS frame, control circuitry 116 controls TX circuitry 120 to respond on the same link with a CTS frame, where the RTS/CTS mechanism requires a TXOP to exchange frames and the CTS frame also carries an indication IND' to accept or reject the operation mode parameter change request. Where the RTS frame is received according to default operating mode parameters (e.g., BW =80 MHz). If the control circuit 116 accepts the operation mode parameter change request, the control circuit 116 controls the RX circuit 118 to change the bandwidth on the link to 160MHz. In other words, the control circuit 116 controls the RX circuit 118 to operate at the changed operating mode parameter (e.g., BW =160 MHz) and other unchanged parameters, and to receive one or more DL PPDUs on the link for the remaining period of the TXOP. Therefore, during the remaining period of TXOP, DL PPDU may be received with BW =160MHz. At the end of the TXOP, the control circuitry 116 controls the RX circuitry 118 to restore the default operating mode parameters (e.g., BW =80 MHz) on the link.

Fig. 5 is a diagram illustrating a fourth dynamic operation mode switching scenario according to an embodiment of the present invention. In this embodiment, wi-Fi MLD104 may be an AP, wi-Fi MLD 102 may be a non-AP STA, and Wi-Fi MLD 102 on a link may set default Transmit (TX) NSS =1 and maximum TX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen for channels. Control circuitry 116 controls TX circuitry 120 to send an RTS frame on a link to initialize a TXOP. The RTS frame is sent according to default operating mode parameters (e.g., TX NSS = 1). In this embodiment, the RTS frame carries an operation mode parameter change indication IND specifying the use of TX NSS = 2. In other words, wi-Fi MLD 102 will control TX circuitry 120 to switch another TX chain (TX chain) to that link for enhanced TX NSS capability. RX circuitry 118 receives a CTS frame from Wi-Fi MLD (which is the AP) 104 on the same link in response to the RTS frame, where the RTS/CTS mechanism requires a TXOP for frame exchange. After the CTS frame is received by RX circuitry 118, control circuitry 116 controls TX circuitry 120 to operate at the changed operating mode parameters (e.g., TX NSS = 2) and other unchanged parameters and to transmit one or more UL PPDUs on the link for the remaining period of the TXOP. Accordingly, the UL PPDU may be transmitted through TX NSS =2 for the remaining period of the TXOP. At the end of the TXOP, control circuitry 116 controls TX circuitry 120 to restore default operating mode parameters (e.g., TX NSS = 1) on the link.

Fig. 6 is a diagram illustrating a fifth dynamic operating mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set a default TX NSS =1 and a maximum TX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen to the channel. The control circuit 116 controls the TX circuit 120 to send an RTS frame on a link and then controls the RX circuit 118 to receive a CTS frame from the Wi-Fi MLD (which is the AP) 104 on the same link in response to the RTS frame. Where the RTS/CTS mechanism requires a TXOP for frame exchange. After the CTS frame is received by RX circuitry 118, control circuitry 116 controls TX circuitry 120 to send a notification frame (notification frame) notifying of the change in operating mode for the subsequent period of the TXOP on the link. In this embodiment, the notification frame carries an operation mode parameter change indication IND specifying the use of TX NSS = 2. In other words, wi-Fi MLD 102 will control TX circuitry 120 to switch another TX chain (TX chain) to that link for enhanced TX NSS capability. Both RTS frames and notification frames are sent based on default operating mode parameters (e.g., TX NSS = 1). After RX circuitry 118 receives a response frame from Wi-Fi MLD (which is the AP) 104 in response to the announcement frame, control circuitry 116 controls TX circuitry 120 to operate at the changed operating mode parameters (e.g., TX NSS = 2) and other unchanged parameters and to transmit one or more UL PPDUs on the link for the remaining period of the TXOP. Accordingly, the UL PPDU may be transmitted by TX NSS =2 for the remaining period of the TXOP. At the end of the TXOP, control circuitry 116 controls TX circuitry 120 to restore default operating mode parameters (e.g., TX NSS = 1) on the link.

As described above, the CTS frame/response frame can carry an operation mode change indication. In some embodiments of the invention, more signaling may be exchanged during the initialization phase of a period (e.g., TXOP), which may further improve the efficiency of the period. For example, the CTS frame/response frame may also carry a sounding request (sounding request) since RX chain switching may require extra sounding (sounding) to guarantee RX quality. For another example, the CTS frame/response frame may also carry a RX chain bitmap (bitmap) that indicates which antennas are used on a certain link for RX operation and allows the sender (sending RTS frame/query frame) to use appropriate beamforming parameters obtained from previous sounding.

Fig. 7 is a diagram illustrating a sixth dynamic operating mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set default RX NSS =1 and maximum RX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen for channels. After RX circuitry 118 receives an RTS frame from Wi-Fi MLD (which is the AP) 104 on a link, control circuitry 116 controls TX circuitry 120 to respond with a CTS frame on the same link, where the RTS/CTS mechanism requires a TXOP for frame exchange. Where the RTS frame is received according to a default operating mode parameter (e.g., RX NSS = 1). In the present embodiment, the CTS frame carries an operation mode parameter change indication IND designating the use of RX NSS =2, and carries a probe request SR. After the Wi-Fi MLD (which is an AP) 104 receives the CTS frame, the Wi-Fi MLD104 accepts the probe request SR, then initiates a probing process by transmitting a Null Data Packet Acknowledgement (NDPA) frame and a Null Data Packet (NDP) frame, and the Wi-Fi MLD (non-AP STA) 102 replies a Channel Quality Indicator (CQI) feedback (feedback, FB) in the probing process. After the CTS frame is transmitted by TX circuitry 120, control circuitry 116 controls RX circuitry 118 to operate at the changed operating mode parameters (e.g., RX NSS = 2) and other unchanged parameters and to receive one or more DL PPDUs on the link for the remainder of the TXOP. Therefore, the DL PPDU may be received through RX NSS =2 for the remaining period of the TXOP. At the end of the TXOP, control circuit 116 controls RX circuit 118 to restore default operating mode parameters (e.g., RX NSS = 1) on the link.

Fig. 8 is a diagram illustrating a seventh dynamic operation mode switching scenario according to an embodiment of the present invention. In this embodiment, the Wi-Fi MLD104 may be an AP, the Wi-Fi MLD 102 may be a non-AP STA, and the Wi-Fi MLD 102 on a link may set default RX NSS =1 and maximum RX NSS =4. On each link, the Wi-Fi MLD 102 operates in a default mode to listen to the channel. RX circuitry 118 receives an RTS frame on a link from Wi-Fi MLD (which is the AP) 104, and control circuitry 116 controls TX circuitry 120 to respond with a CTS frame on the same link, where the RTS/CTS mechanism requires a TXOP for frame exchange. Where the RTS frame is received according to a default operating mode parameter (e.g., RX NSS = 1). In this embodiment, the CTS frame carries an operation mode parameter change indication IND that specifies using RX NSS =2, and also carries an RX chain bitmap BMP. After the Wi-Fi MLD (i.e., AP) 104 receives the CTS frame, the Wi-Fi MLD104 decides to probe with reference to a RX chain bitmap BMP indicating the RX NSS employed by the Wi-Fi MLD (which is an AP-less STA) 102, and initiates a probing process by sending an NDPA frame and an NDP frame. The Wi-Fi MLD 102 replies with a CQI FB during the sounding procedure, wherein the CQI FB is based on the RX bitmap BMP carried in the CTS frame. After the CTS frame is transmitted by TX circuitry 120, control circuitry 116 controls RX circuitry 118 to operate at the changed operating mode parameters (e.g., RX NSS = 2) and other unchanged parameters and to receive one or more DL PPDUs on the link for the remainder of the TXOP. Therefore, the DL PPDU may be received through RX NSS =2 for the remaining period of the TXOP. At the end of the TXOP, control circuit 116 controls RX circuitry 118 to restore default operating mode parameters (e.g., RX NSS = 1) on the link.

Fig. 9 is a diagram illustrating additional signaling provided by channel quality indicator (channel quality indicator) feedback according to an embodiment of the present invention. For any sounding procedure (NDPA + NDP + CQI FB) applied to any Link of Multi-Link Operation (MLO), the CQI FB may also carry the RX chain bitmap BMP. In this way, a reduction in sounding overhead can be achieved if the same RX chain is used on some links in the future.

In the above embodiment, the AP MLD uses the RTS frame as the initial control frame of the frame exchange sequence. However, these are for illustrative purposes only and are not meant to be limitations of the present invention. In some embodiments of the present invention, the initial control Frame of the Frame exchange sequence initiated by the AP MLD may be a Trigger Frame (TF), such as a Multi-User Request To Send (MU-RTS) Frame or a Buffer Status Report Poll (BSRP) Frame. Fig. 10-14 illustrate additional dynamic operating mode switching scenarios. In the case where an AP MLD (e.g., one of the Wi-

Fi MLDs

102 and 104 shown in fig. 1) sends a MU-RTS frame as a trigger frame TF, a non-AP MLD (e.g., the other of the Wi-

Fi MLDs

102 and 104 shown in fig. 1) may respond with a CTS frame as a response frame RF after receiving the MU-RTS frame. In another case where an AP MLD (e.g., one of the Wi-

Fi MLDs

102 and 104 shown in fig. 1) transmits a BSRP frame as the trigger frame TF, a non-AP MLD (e.g., the other of the Wi-

Fi MLDs

102 and 104 shown in fig. 1) may respond with a Buffer Status Report (BSR) frame as the response frame RF after receiving the BSRP frame. The operating mode change signaling design employed by the RTS/CTS mechanism may also be employed by the MU-RTS/CTS mechanism and the BSRP/BSR mechanism. Details of the dynamic operating mode switching example shown in fig. 10-14 are omitted herein for the sake of brevity, as those of ordinary skill in the art can readily understand the details of the dynamic operating mode switching example shown in fig. 10-14 after reading the above paragraphs directed to fig. 2-4 and fig. 7-8. It should be noted that one Wi-Fi MLD of the present invention may support one or more of the dynamic operating mode switching scenarios described above.

Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A Wi-Fi multilink device, comprising:

a transmitting circuit;

a receiving circuit; and

control circuitry to control the receive circuitry to receive a first frame under an operating mode parameter having a first setting, to control the transmit circuitry to transmit a second frame in response to the first frame under the operating mode parameter having the first setting, and to control the receive circuitry to receive at least one physical layer protocol data unit under an operating mode parameter having a second setting after the second frame is transmitted, wherein the second setting is different from the first setting;

wherein, prior to receiving the first frame, the control circuitry is further to control the receive circuitry to receive a third frame at the operating mode parameter having the first setting and to control the transmit circuitry to transmit a fourth frame responsive to the third frame at the operating mode parameter having the first setting;

wherein the third frame is one of a request to send frame, a multi-user request to send frame, and a buffer status report poll frame, and the fourth frame is one of a clear to send frame and a buffer status report frame.

2. The Wi-Fi multilink device of claim 1, wherein one of the third frame and the fourth frame carries an operating mode parameter change indication specifying use of the second setting.

3. The Wi-Fi multilink device of claim 1, wherein neither the third frame nor the fourth frame carries an operation mode parameter change indication specifying use of the second setting.

4. The Wi-Fi multilink device of claim 1, wherein the fourth frame further carries a probe request.

5. The Wi-Fi multilink device of claim 1, wherein the fourth frame also carries a receive chain bitmap.

6. The Wi-Fi multi-link device of claim 1,

wherein the first frame is a query frame and the second frame is a response frame responsive to the query frame and carrying an indication of a change in operating mode parameters specifying use of the second setting.

7. The Wi-Fi multilink device of claim 6, wherein the response frame further carries a probe request.

8. The Wi-Fi multilink device of claim 6, wherein the response frame further carries a receive chain bitmap.

9. The Wi-Fi multi-link device of claim 1, wherein the control circuitry is further to control the transmit circuitry to send a channel quality indication feedback frame during sounding, the channel quality indication feedback frame carrying a receive chain bitmap.

10. The Wi-Fi multilink device of claim 1, wherein the operating mode parameter is at least one of a number of spatial streams, a bandwidth, a decoding capability, a maximum medium access control protocol data unit length, a maximum aggregate medium access control service data unit length, or a maximum aggregate medium access control protocol data unit length index.

11. The Wi-Fi multilink device of claim 1, wherein the at least one physical layer protocol data unit is received during a transmission opportunity, and the control circuit is further to control the receive circuit to resume the operating mode parameters with the first setting at an end of the transmission opportunity.

12. A Wi-Fi multi-link device, comprising:

a transmitting circuit;

a receiving circuit; and

control circuitry to control the transmit circuitry to transmit a first frame under an operating mode parameter having a first setting, to control the receive circuitry to receive a second frame in response to the first frame under the operating mode parameter having the first setting, and to control the transmit circuitry to transmit at least one physical layer protocol data unit under an operating mode parameter having a second setting after receiving the second frame, wherein the second setting is different from the first setting;

wherein, prior to transmitting the first frame, the control circuit is further configured to control the transmit circuit to transmit a request-to-transmit frame under an operation mode parameter having a first setting, and to control the receive circuit to receive a clear-to-transmit frame in response to the request-to-transmit frame under the operation mode parameter having the first setting.

13. The Wi-Fi multilink device of claim 12, wherein the request to send frame carries an operation mode parameter change indication specifying use of the second setting.

14. The Wi-Fi multi-link device of claim 12, wherein the request to send frame does not carry an operation mode parameter change indication specifying use of the second setting.

15. The Wi-Fi multi-link apparatus of claim 12,

the first frame is a notification frame carrying an operation mode parameter change indication specifying use of the second setting, and the second frame is a response frame responding to the notification frame.

16. The Wi-Fi multilink device of claim 12, wherein the operating mode parameter is at least one of a number of spatial streams, a bandwidth, a decoding capability, a maximum medium access control protocol data unit length, a maximum aggregate medium access control service data unit length, or a maximum aggregate medium access control protocol data unit length index.

17. The Wi-Fi multilink device of claim 12, wherein the at least one physical layer protocol data unit is sent during a transmission opportunity, and the control circuit is further to control the transmit circuit to resume the operating mode parameters with the first setting at an end of the transmission opportunity.

18. A wireless communication method employed by a Wi-Fi multilink device, comprising:

controlling a receiving circuit to receive a first frame under an operation mode parameter having a first setting;

control transmit circuitry to transmit a second frame in response to the first frame under the operating mode parameter having the first setting;

after the second frame is transmitted, controlling the receiving circuitry to receive at least one physical layer protocol data unit in an operating mode parameter having a second setting, wherein the second setting is different from the first setting;

wherein, prior to receiving the first frame, the receive circuitry is further controlled to receive a third frame at the operating mode parameter having the first setting, and to control the transmit circuitry to transmit a fourth frame responsive to the third frame at the operating mode parameter having the first setting;

19. A method of wireless communication employed by a Wi-Fi multilink device, comprising:

controlling a transmitting circuit to transmit a first frame under an operation mode parameter having a first setting;

control a receiving circuit to receive a second frame in response to the first frame at the operating mode parameter having the first setting; and

after receiving the second frame, controlling the transmit circuitry to transmit at least one physical layer protocol data unit under an operating mode parameter having a second setting, wherein the second setting is different from the first setting;

wherein, before transmitting the first frame, the transmission circuit is further controlled to transmit a request-to-transmit frame under an operation mode parameter having a first setting, and the reception circuit is controlled to receive a transmission-permitted frame in response to the request-to-transmit frame under the operation mode parameter having the first setting.