Method for recovering permission to use transmission opportunity and relevant device

Abstract

To provide an invention related to a field of radio communication, especially, a method for recovering permission to use transmission opportunity and a relevant device.SOLUTION: A method includes the following steps. A first device receives a first frame from a second device. The first device recovers permission to use transmission opportunity TXOP on the basis of the first frame. The first frame indicates that the second device's using first time resource is stopped. The first time resource is allocated to the second device from the acquired TXOP by the first device, by using a single user trigger frame. The first frame can indicate that the second device's using the allocated time resource (first time resource) is stopped, so that the first device previously withdraws / recovers permission to use the TXOP, on the basis of the instruction of the first frame. Thereby, a use rate of the channel resource and reliability of the recovery of the permission to use the TXOP can be improved.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202110056633.4, entitled "Method and Related Apparatus for Restoring Permission to Use Transmission Opportunities," filed with the State Intellectual Property Office of China on January 15, 2021, and Chinese Patent Application No. 202110437428.2, entitled "Method and Related Apparatus for Restoring Permission to Use Transmission Opportunities," filed with the State Intellectual Property Office of China on April 22, 2021, both of which are incorporated by reference in their entirety herein.

[0002] Technical Field TECHNICAL FIELD This application relates to the field of wireless communication technologies, and more particularly to a method and related apparatus for recovering permission to use a transmission opportunity. [Background technology]

[0003] The 802.11 protocol suite is a set of communications standards defined by the Institute of Electrical and Electronics Engineers (IEEE) for wireless local area networks (WLANs), starting with IEEE 802.11a / b / g, through IEEE 802.11n and IEEE 802.11ac, with IEEE 802.11ax and IEEE 802.11be under development.

[0004] Generally, the physical layer (PHY) frame in the IEEE 802.11 standard is also called the physical layer protocol data unit (PPDU). The IEEE 802.11 ax standard proposes four frame structures: high efficiency single-user PPDU (HE SU PPDU), high efficiency multi-user PPDU (HE MU PPDU), high efficiency trigger based PPDU (HE TB PPDU), and high efficiency extended range PPDU (HE ER PPDU). In the IEEE 802.11ax standard, the HE SU PPDU applies to the scenario where a station (STA) transmits data to another STA, and can be applied to uplink transmission and downlink transmission. The HE TB PPDU applies to a scenario in which an access point (AP) sends a trigger frame (TF) to schedule non-AP STAs for uplink transmission.

[0005] In the current IEEE802.11ax standard, the trigger frame can only trigger the HE TB PPDU, but not the HE SU PPDU. However, since the AP usually has a stronger channel access capability, the next generation IEEE802.11be standard needs to support the AP-triggered SU PPDU. Therefore, to implement the AP-triggered SU PPDU, the AP may send a single-user trigger frame to allocate some or all of the remaining time resources in the transmission opportunity (TXOP) to the associated STA (for simplicity, hereafter referred to as the designated STA for short). The designated STA can then communicate with another STA or the AP in the allocated time resource. However, if the duration of the time resource allocated by the AP to the designated STA is long and the designated STA completes the required transmission after using the time resource for a certain time period (i.e., there is a remaining duration in the allocated time resource), or if the designated STA finds that the remaining duration is insufficient to transmit a complete SU PPDU after using the time resource for a certain time period, the remaining duration may cause a waste of channel resources and allow another station to obtain permission to use the channel through contention. However, the AP cannot recover the permission to use the TXOP. Therefore, how to improve the channel utilization and the reliability of TXOP recovery is an urgent problem to be solved now. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE DISCLOSURE The embodiments of the present application provide a method and related apparatus for recovering permission to use a transmission opportunity, so as to improve channel resource utilization and reliability of recovering permission to use a TXOP.

[0007] The following describes the present application from different aspects. It should be understood that cross-reference can be made to the following implementations and beneficial effects of the different aspects. [Means for solving the problem]

[0008] According to a first aspect, the present application provides a method for recovering permission to use a transmission opportunity. The method includes: a first device receives a first frame from a second device. The first device recovers permission to use a TXOP based on the first frame. The first frame indicates that the second device has stopped using a first time resource. The first time resource is allocated to the second device from an obtained transmission opportunity TXOP by using a single-user trigger frame by the first device. That is, the second device may return permission to use a TXOP by transmitting the first frame to the first device. The first device may be an AP, the second device may be a STA, or the second device may be another AP.

[0009] In this embodiment of the present application, the first frame may indicate that the second device has stopped using the allocated time resource (first time resource), and thus the first device may revoke / recover permission to use TXOP in advance based on the first frame received from the second device. This improves the utilization of channel resources. Also, in this manner of returning permission to use TXOP by transmitting the first frame, other stations may not be able to obtain permission to use the channel through contention during the remaining duration included in the first time resource. This improves the reliability of the recovery of permission to use TXOP.

[0010] Regarding the first aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field. The first field indicates the remaining time resource of the TXOP, and the second field indicates the first time resource. That is, this embodiment of the present application is applicable to an AP-triggered SU PPDU scenario. Therefore, the channel resource utilization and TXOP recovery reliability in the trigger-based SU PPDU scenario can be improved.

[0011] Regarding the first aspect, in one possible implementation, the first frame carries first indication information, which indicates that the second device has stopped using the first time resource. Specifically, the first device parses the first indication information carried in the first frame, and the first device revokes / recovers the permission to use the TXOP in advance based on the first indication information. This can improve channel resource utilization.

[0012] Regarding the first aspect, in one possible implementation, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0013] In this embodiment of the present application, the first device parses the first indication information and the second indication information carried in the first frame, so that the first device can revoke / recover permission to use TXOP in advance and know whether the second device has further time resource allocation request. For example, when the duration of the time resource (i.e., the first time resource) allocated by the first device to the second device is short, if the second device does not complete the required transmission after using the time resource for a certain period of time, but finds that the remaining duration of the first time resource is insufficient to transmit a complete SU PPDU, by using the first frame carrying the first indication information and the second indication information, the first device can revoke / recover permission to use TXOP in advance and prevent the waste of the remaining duration. Furthermore, the second device can reapply to the first device for time resource, and the signaling overhead used to apply for time resource can be reduced.

[0014] Regarding the first aspect, in one possible implementation, the A-control field in the first frame includes the first indication information, or the A-control field in the first frame includes the first indication information and the second indication information. That is, in this application, the meaning of the A-control field included in an existing type of frame (e.g., a QoS data frame or a QoS null data frame) is enhanced / modified to indicate that the second device has stopped using the first time resource. This can reduce the complexity of implementing the solution.

[0015] Regarding the first aspect, in one possible implementation, the control identifier of the A-control field is a first value. The first value indicates that the A-control field contains first indication information. That is, in this embodiment of the present application, the new A-control field is designed to indicate that the second device has stopped using the first time resource. This can improve the versatility of implementing the solution.

[0016] Regarding the first aspect, in one possible implementation, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field, and the second indication is carried in at least one bit in bits 4 to 8 in the CAS control field.

[0017] In this embodiment of the present application, the existing A control field (i.e., the CAS control field) is improved to indicate that the second device has stopped using the first time resource, or to indicate that the second device has stopped using the first time resource and indicates whether the second device needs more time resources for data transmission, which can further simplify the complexity of implementing the solution.

[0018] Regarding the first aspect, in one possible implementation, the frame type field in the first frame indicates that the first frame is a control frame, and the frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource. That is, in this embodiment of the present application, a new type of frame is designed to specifically indicate that the second device returns permission to use TXOP. This can improve the flexibility and versatility of implementing the solution.

[0019] According to a second aspect, the present application provides a method for recovering permission to use a transmission opportunity, the method including: a second device determining a first frame, and the second device transmitting the first frame to the first device, the first frame indicating that the second device has stopped using a first time resource, the first time resource being allocated to the second device from a transmission opportunity TXOP obtained by the first device by using a single-user trigger frame.

[0020] Regarding the second aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0021] Regarding the second aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0022] Regarding the second aspect, in one possible implementation, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0023] Regarding the second aspect, in one possible implementation, the A-control field in the first frame includes the first indication information, or the A-control field in the first frame includes the first indication information and the second indication information.

[0024] Regarding the second aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0025] Regarding the second aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0026] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0027] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0028] Regarding the second aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0029] Regarding the second aspect, in one possible implementation, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0030] In this embodiment of the present application, if the first frame is a quality of service QoS null data frame or if the first frame is a new type of frame that specifically indicates a return, the first frame is allowed to transmit after the end of the first time resource. In this way, other stations may not be able to obtain permission to use the channel through contention in the first time resource, and the reliability of recovering permission to use the TXOP is improved.

[0031] According to a third aspect, the present application provides a method for recovering permission to use a transmission opportunity. The method includes: a first device receives a second frame. If the duration between the end of the transmission of the second frame and the end of the first time resource is shorter than a preset duration T, the first device recovers permission to use a transmission opportunity TXOP. The destination address of the second frame is the address of the second device. Alternatively, the sender address of the second frame is the address of the second device, and the second frame is a frame that does not require a response frame. The first time resource is allocated by the first device to the second device from the obtained TXOP. That is, the first device may determine a value relationship between a time threshold (i.e., a preset duration T) and a duration T' between the end of the reception of the second frame and the end of the first time resource to determine whether to recover permission to use a TXOP in advance. In this solution, a time threshold T is set. Even if T' is less than T, permission to use a TXOP may be pre-recovered to improve channel resource utilization.

[0032] Regarding the third aspect, in one possible implementation, the first device receives a first frame from the second device when a duration between an end of the second frame and an end of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0033] In this embodiment of the present application, if T' is greater than T, the first frame may indicate that the second device has stopped using the allocated time resource (first time resource), so that the first device can revoke / recover permission to use TXOP in advance based on the first frame received from the second device. This improves the utilization of channel resources. Also, other stations may not be able to obtain permission to use the channel through contention during the remaining duration included in the first time resource, so that the reliability of recovering permission to use TXOP is improved.

[0034] Regarding the third aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field. The first field indicates the remaining time resource of the TXOP, and the second field indicates the first time resource. That is, this embodiment of the present application is applicable to an AP-triggered SU PPDU scenario. Therefore, the channel resource utilization and TXOP recovery reliability in the trigger-based SU PPDU scenario can be improved.

[0035] Regarding the third aspect, in one possible implementation, the first frame carries first indication information. The first indication information indicates that the second device has stopped using the first time resource. Specifically, the first device parses the first indication information carried in the first frame, and the first device revokes / recovers the permission to use the TXOP in advance based on the first indication information. This can improve channel resource utilization.

[0036] Regarding the third aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0037] In this embodiment of the present application, the first device parses the first indication information and the second indication information carried in the first frame, so that the first device can revoke / recover permission to use TXOP in advance, and can know whether the second device has further time resource allocation request. For example, when the duration of the time resource (i.e., the first time resource) allocated by the first device to the second device is short, if the second device uses the time resource for a certain period of time and does not complete the required transmission, but finds that the remaining duration of the first time resource is insufficient to transmit a complete SU PPDU, the first device can revoke / recover permission to use TXOP in advance by using the first frame carrying the first indication information and the second indication information, and prevent the waste of the remaining duration. Furthermore, the second device may reapply to the first device for the time resource, which can reduce the signaling overhead used to apply for the time resource.

[0038] Regarding the third aspect, in one possible implementation, the A-control field in the first frame includes the first indication information, or the A-control field in the first frame includes the first indication information and the second indication information. That is, in this application, the meaning of the A-control field included in an existing type of frame (e.g., a QoS data frame or a QoS null data frame) is enhanced / modified to indicate that the second device has stopped using the first time resource. This can reduce the complexity of implementing the solution.

[0039] Regarding the third aspect, in one possible implementation, the control identifier of the A-control field is a first value. The first value indicates that the A-control field contains first indication information. That is, in this embodiment of the present application, a new A-control field is designed to indicate that the second device has stopped using the first time resource. This can improve the versatility of implementing the solution.

[0040] Regarding the third aspect, in one possible implementation, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit in bits 4 to 8 in the CAS control field.

[0041] In this embodiment of the present application, the existing A control field (i.e., the CAS control field) is enhanced to indicate that the second device has stopped using the first time resource, or indicate that the second device has stopped using the first time resource and indicates whether the second device needs more time resources for data transmission, which can further simplify the complexity of implementing the solution.

[0042] Regarding the third aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame, and a frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource. That is, in this embodiment of the present application, a new type of frame is designed to specifically indicate that the second device returns permission to use TXOP. This can improve the flexibility and versatility of implementing the solution.

[0043] According to a fourth aspect, the present application provides a method for recovering permission to use a transmission opportunity, the method including: a second device receives or transmits a second frame, the second frame being a frame that does not require a response frame, and if the duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T, the second device does not transmit any more PPDUs.

[0044] Specifically, when the second device receives an acknowledgement frame (i.e., the second frame) at any time in the first time resource or transmits a frame (i.e., the second frame) that does not request a response frame at any time in the first time resource, if it determines that the duration T' between the end of the second frame and the end of the first time resource is shorter than T, the second device assumes by default that the first device has regained use of the TXOP, i.e., the second device is no longer allowed to transmit a SU PPDU in the remaining duration of the first time resource, preventing the second device from failing to transmit the SU PPDU.

[0045] Regarding the fourth aspect, in one possible implementation, if the duration between the end of the second frame and the end of the first time resource is greater than a preset duration T, the second device transmits a first frame to the first device, the first frame indicating that the second device has stopped using the first time resource. The first time resource is allocated by the first device to the second device from the acquired TXOP.

[0046] That is, if T' is greater than T, the first frame may indicate that the second device has stopped using the allocated time resource (first time resource). Therefore, the first device can revoke / recover permission to use the TXOP in advance based on the first frame received from the second device. Thus, the utilization of the channel resource is improved. Also, the reliability of recovering permission to use the TXOP is improved, since other stations may not be able to obtain permission to use the channel through contention during the remaining duration included in the first time resource.

[0047] Regarding the fourth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates the remaining time resource of the TXOP and the second field indicates the first time resource.

[0048] Regarding the fourth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0049] Regarding the fourth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0050] Regarding the fourth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0051] Regarding the fourth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0052] Regarding the fourth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0053] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0054] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0055] With respect to the fourth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0056] With respect to the fourth aspect, in one possible implementation, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if an end time of the first frame is later than an end time of the first time resource and a start time of the first frame is earlier than an end time of the first time resource.

[0057] In this embodiment of the present application, if the first frame is a quality of service QoS null data frame or if the first frame is a new type of frame that specifically indicates a return, the first frame is allowed to be transmitted after the end of the first time resource, thus improving the reliability of recovering the permission to use the TXOP, without other stations having to obtain permission to use the channel through contention during the remaining duration included in the first time resource.

[0058] According to a fifth aspect, the present application provides a method for recovering permission to use a transmission opportunity. The method includes: a first device transmits a second frame, where the destination address of the second frame is the address of the second device. If the duration between the end of the second frame and the end of the first time resource is shorter than a preset duration T, the first device recovers permission to use a transmission opportunity TXOP. The first time resource is allocated by the first device to the second device from the obtained TXOP. That is, in a UL scenario, the first device can further transmit an acknowledgement frame (i.e., the second frame) with the address of the second device as the destination address at any time in the first time resource. If the first device determines that the duration T' between the end of the acknowledgement frame and the end of the first time resource is shorter than the preset duration T, the first device may recover permission to use the TXOP in advance, improving the utilization of channel resources.

[0059] With respect to the fifth aspect, in one possible implementation, the first device receives a first frame from the second device when a duration between an end of the second frame and an end of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0060] Regarding the fifth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates the remaining time resource of the TXOP and the second field indicates the first time resource.

[0061] Regarding the fifth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0062] Regarding the fifth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0063] Regarding the fifth aspect, in one possible implementation, the A-control field in the first frame includes the first indication information, or the A-control field in the first frame includes the first indication information and the second indication information.

[0064] Regarding the fifth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0065] With respect to the fifth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0066] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0067] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0068] With respect to the fifth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0069] According to a sixth aspect, the present application provides a method for recovering permission to use a transmission opportunity, the method including: a second device receives a second frame from a first device, and if a duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T, the second device does not transmit any more PPDUs.

[0070] Regarding the sixth aspect, in one possible implementation, if the duration between the end of the second frame and the end of the first time resource is longer than a preset duration T, the second device transmits a first frame to the first device, the first frame indicating that the second device has stopped using the first time resource, and the first time resource is allocated by the first device to the second device from the acquired TXOP.

[0071] Regarding the sixth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0072] Regarding the sixth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0073] Regarding the sixth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0074] Regarding the sixth aspect, in one possible implementation, the A-control field in the first frame includes the first indication information, or the A-control field in the first frame includes the first indication information and the second indication information.

[0075] Regarding the sixth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0076] With respect to the sixth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0077] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0078] Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit among the fourth to eighth bits in the CAS control field.

[0079] With respect to the sixth aspect, in one possible implementation, the frame type field in the first frame indicates that the first frame is a control frame and the frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0080] With respect to the sixth aspect, in one possible implementation, if the first frame is a quality of service (QoS) null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if an end time of the first frame is later than an end time of the first time resource and a start time of the first frame is earlier than an end time of the first time resource.

[0081] According to a seventh aspect, the present application provides a method for recovering permission to use a transmission opportunity, the method including: a first device determining a third frame, and the first device transmitting the third frame to a second device, the third frame indicating that the first device actively recovers permission to use a transmission opportunity TXOP.

[0082] In this embodiment of the present application, if an AP needs to revoke permission to use a TXOP for some reason (e.g., an urgent service arrives that will transmit immediately), the AP can actively recover / revoke the AP's permission to use a TXOP by sending an active recovery frame (i.e., the third frame in this application).

[0083] Regarding the seventh aspect, in one possible implementation, the third frame is a block acknowledgement (BA) frame returned by the first device based on the data frame received from the second device, wherein a BA control field in the BA frame indicates that the first device actively regains permission to use the TXOP.

[0084] In this embodiment of the present application, the existing enhanced BA control field in the BA frame is enhanced to indicate that the first device actively recovers permission to use the TXOP, which can reduce the complexity of implementing the solution.

[0085] With respect to the seventh aspect, in one possible implementation, the third frame is an aggregated frame, and the aggregated frame is obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, and the BA frame is generated by the first device based on a data frame received from the second device.

[0086] In this embodiment of the present application, another frame (i.e., the fourth frame) transmitted by aggregating with the BA frame indicates that the first device actively recovers the permission to use the TXOP, thus improving the versatility of implementing the solution.

[0087] Regarding the seventh aspect, in one possible implementation, the A-control field in the fourth frame includes a third indication, the third indication indicating that the first device actively recovers permission to use the TXOP.

[0088] In this embodiment of the present application, a QoS data frame or a QoS null data frame including an A control field in the fourth frame indicates that the first device actively regains permission to use the TXOP, thereby reducing the complexity of implementing the solution.

[0089] Regarding the seventh aspect, in one possible implementation, the control identifier of the A-control field is a third value, the third value indicating that the A-control field includes third indication information.

[0090] With respect to the seventh aspect, in one possible implementation, a frame type field in the third frame indicates that the third frame is a control frame and a frame subtype field in the third frame indicates that the third frame is an active recovery frame, the active recovery frame indicating that the first device actively recovers permission to use a transmission opportunity TXOP.

[0091] In this embodiment of the present application, a new type of frame, namely the fourth frame, is specifically designed to indicate that the first device actively recovers the permission to use TXOP, thus improving the versatility of implementing the solution.

[0092] According to an eighth aspect, the present application provides a method for recovering permission to use a transmission opportunity, the method including: upon receiving a third frame from the first device, the second device does not transmit any more data frames or retransmits the data frame k times, the third frame indicating that the first device actively recovers permission to use a transmission opportunity TXOP, where k is an integer greater than 0.

[0093] Regarding the eighth aspect, in one possible implementation, the third frame is a block acknowledgement BA frame returned by the first device based on the data frame received from the second device, wherein a BA control field in the BA frame indicates that the first device actively recovers permission to use the TXOP.

[0094] With respect to the eighth aspect, in one possible implementation, the third frame is an aggregated frame, and the aggregated frame is obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, and the BA frame is generated by the first device based on a data frame received from the second device.

[0095] Regarding the eighth aspect, in one possible implementation, the A-control field in the fourth frame includes third indication information, the third indication information instructing the first device to actively recover permission to use the TXOP.

[0096] Regarding the eighth aspect, in one possible implementation, the control identifier of the A-control field is a third value, the third value indicating that the A-control field includes third indication information.

[0097] With respect to the eighth aspect, in one possible implementation, a frame type field of the third frame indicates that the third frame is a control frame and a frame subtype field of the third frame indicates that the third frame is an active recovery frame. The active recovery frame indicates that the first device is actively recovering permission to use a transmission opportunity TXOP.

[0098] According to a ninth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a first device or a chip in the first device, for example a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a transceiver unit configured to receive a first frame from a second device, the first frame indicating that the second device has stopped using a first time resource, the first time resource being allocated to the second device from a transmission opportunity TXOP acquired by the first device, the first time resource being allocated to the second device by the first device by using a single-user trigger frame; and a processing unit configured to recover permission to use the TXOP based on the first frame.

[0099] With respect to the ninth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0100] With respect to the ninth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0101] Regarding the ninth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0102] Regarding the ninth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0103] Regarding the ninth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0104] Regarding the ninth aspect, in one possible implementation, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit in bits 4 to 8 in the CAS control field.

[0105] With respect to the ninth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0106] According to a tenth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a second device or a chip in the second device, such as a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a processing unit configured to determine a first frame, the first frame indicating that the second device has stopped using a first time resource, the first time resource being allocated by the first device to the second device from an acquired transmission opportunity TXOP, the first time resource being allocated by the first device to the second device by using a single-user trigger frame; and a transceiver unit configured to transmit the first frame to the first device.

[0107] With respect to the tenth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0108] Regarding the tenth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0109] Regarding the tenth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0110] Regarding the tenth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0111] Regarding the tenth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0112] Regarding the tenth aspect, in one possible implementation, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit in bits 4 to 8 in the CAS control field.

[0113] With respect to the tenth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0114] With respect to the tenth aspect, in one possible implementation, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0115] According to an eleventh aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a first device or a chip in the first device, for example a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a transceiver unit configured to receive a second frame; and a processing unit configured to recover permission to use a transmission opportunity TXOP if a duration between a transmission end point of the second frame and an end point of the first time resource is shorter than a preset duration T. The destination address of the second frame is an address of the second device. Alternatively, the sender address of the second frame is an address of the second device, and the second frame is a frame that does not require a response frame. The first time resource is allocated by the first device to the second device from the obtained TXOP.

[0116] With respect to the eleventh aspect, in one possible implementation, the transceiver unit is further configured to: receive a first frame from the second device when a duration between an end of the second frame and an end of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0117] Regarding the eleventh aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0118] Regarding the eleventh aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0119] Regarding the eleventh aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0120] Regarding the eleventh aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0121] Regarding the eleventh aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0122] Regarding the eleventh aspect, in one possible implementation, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit in bits 4 to 8 in the CAS control field.

[0123] With respect to the eleventh aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame, and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0124] According to a twelfth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a second device or a chip in the second device, such as a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a transceiver unit configured to receive or transmit a second frame. The second frame is a frame that does not require a response frame. If the duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T, the second device does not transmit any more PPDUs.

[0125] Regarding the twelfth aspect, in one possible implementation, the second device further includes a processing unit configured to: determine to transmit, using the transceiver unit, a first frame to the first device if a duration between an end of the second frame and an end of the first time resource is greater than a preset duration T; the first frame indicates that the second device has stopped using the first time resource; and the first time resource is allocated by the first device to the second device from the acquired TXOP.

[0126] Regarding the twelfth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0127] Regarding the twelfth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0128] Regarding the twelfth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0129] Regarding the twelfth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0130] Regarding the twelfth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0131] Regarding the twelfth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0132] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0133] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0134] With respect to the twelfth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0135] With respect to the twelfth aspect, in one possible implementation, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0136] According to a thirteenth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a first device or a chip in the first device, for example a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a transceiver unit configured to transmit a second frame, a destination address of the second frame being an address of the second device; and a processing unit configured to recover permission to use a transmission opportunity TXOP if a duration between an end of the second frame and an end of a first time resource is shorter than a preset duration T. The first time resource is allocated by the first device to the second device from an acquired TXOP.

[0137] With respect to the thirteenth aspect, in one possible implementation, the processing unit is configured to: determine to receive, using the transceiver unit, a first frame from the second device if a duration between an end of the second frame and an end of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0138] With respect to the thirteenth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0139] Regarding the thirteenth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0140] Regarding the thirteenth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0141] With regard to the thirteenth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0142] Regarding the thirteenth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0143] Regarding the thirteenth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0144] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0145] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0146] With respect to the thirteenth aspect, in one possible implementation, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, where the time resource return frame indicates that the second device has stopped using the first time resource.

[0147] According to a fourteenth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a second device or a chip in the second device, such as a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a transceiver unit configured to receive a second frame from a first device; and a processing unit configured to determine that the second device will not transmit any more PPDUs if a duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T.

[0148] With respect to the fourteenth aspect, in one possible implementation, the processing unit is further configured to: transmit, using the transceiver unit, a first frame to the first device if a duration between an end of the second frame and an end of the first time resource is longer than a preset duration T. The first frame indicates that the second device has stopped using the first time resource. The first time resource is allocated by the first device to the second device from the obtained TXOP.

[0149] With respect to the fourteenth aspect, in one possible implementation, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication, and the single-user trigger frame includes a first field and a second field, where the first field indicates a remaining time resource of the TXOP and the second field indicates the first time resource.

[0150] Regarding the fourteenth aspect, in one possible implementation, the first frame carries first indication information, the first indication information indicating that the second device has stopped using the first time resource.

[0151] Regarding the fourteenth aspect, in one possible implementation, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0152] Regarding the fourteenth aspect, in one possible implementation, the A control field in the first frame includes the first indication information, or the A control field in the first frame includes the first indication information and the second indication information.

[0153] Regarding the fourteenth aspect, in one possible implementation, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0154] Regarding the fourteenth aspect, in one possible implementation, the control identifier of the A-control field is a second value, the second value indicating that the A-control field is a command and status CAS control field.

[0155] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0156] Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit among the fourth to eighth bits in the CAS control field.

[0157] With respect to the fourteenth aspect, in one possible implementation, the frame type field in the first frame indicates that the first frame is a control frame and the frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0158] With respect to the fourteenth aspect, in one possible implementation, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0159] According to a fifteenth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a first device or a chip in the first device, such as a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a processing unit configured to determine a third frame; and a transceiver unit configured to transmit the third frame to a second device. The third frame indicates that the first device actively recovers permission to use the transmission opportunity TXOP.

[0160] Regarding the fifteenth aspect, in one possible implementation, the third frame is a block acknowledgement (BA) frame returned by the first device based on the data frame received from the second device, wherein a BA control field in the BA frame indicates that the first device actively recovers permission to use the TXOP.

[0161] With respect to the fifteenth aspect, in one possible implementation, the third frame is an aggregated frame, and the aggregated frame is obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, and the BA frame is generated by the first device based on a data frame received from the second device.

[0162] Regarding the fifteenth aspect, in one possible implementation, the A-control field in the fourth frame includes third indication information, the third indication information instructing the first device to actively recover permission to use the TXOP.

[0163] Regarding the fifteenth aspect, in one possible implementation, the control identifier of the A-control field is a third value, the third value indicating that the A-control field includes third indication information.

[0164] With respect to the fifteenth aspect, in one possible implementation, a frame type field in the third frame indicates that the third frame is a control frame and a frame subtype field in the third frame indicates that the third frame is an active recovery frame. The active recovery frame indicates that the first device is actively recovering permission to use a transmission opportunity TXOP.

[0165] According to a sixteenth aspect, the present application provides an apparatus for recovering permission to use a transmission opportunity. The apparatus for recovering permission to use a transmission opportunity may be a second device or a chip in the second device, for example a Wi-Fi chip. The apparatus for recovering permission to use a transmission opportunity includes: a processing unit configured to determine that when the second device receives a third frame from the first device, the second device will not transmit any more data frames using the transceiver unit, or will retransmit the data frame k times using the transceiver unit. The third frame indicates that the first device actively recovers permission to use a transmission opportunity TXOP. k is an integer greater than 0.

[0166] Regarding the sixteenth aspect, in one possible implementation, the third frame is a block acknowledgement BA frame returned by the first device based on the data frame received from the second device, wherein a BA control field in the BA frame indicates that the first device actively regains permission to use the TXOP.

[0167] With respect to the sixteenth aspect, in one possible implementation, the third frame is an aggregated frame, and the aggregated frame is obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, and the BA frame is generated by the first device based on a data frame received from the second device.

[0168] Regarding the sixteenth aspect, in one possible implementation, the A-control field in the fourth frame includes a third indication, the third indication indicating that the first device actively recovers permission to use the TXOP.

[0169] Regarding the sixteenth aspect, in one possible implementation, the control identifier of the A-control field is a third value, the third value indicating that the A-control field includes third indication information.

[0170] With respect to the sixteenth aspect, in one possible implementation, a frame type field of the third frame indicates that the third frame is a control frame and a frame subtype field of the third frame indicates that the third frame is an active recovery frame, the active recovery frame indicating that the first device actively recovers permission to use a transmission opportunity TXOP.

[0171] According to a seventeenth aspect, the present application provides a communication device. The communication device is specifically the first device in the first, third, fifth or seventh aspect, and includes a processor and a transceiver. The processor is configured to support the first device to perform corresponding functions in the above method. The transceiver is configured to support communication of the first device to receive or transmit information, frames or instructions in the above method. The first device may further include a memory. The memory is configured to be coupled to the processor and stores necessary program instructions and data for the first device.

[0172] According to an eighteenth aspect, the present application provides a communication device. The communication device is specifically the second device in the second, fourth, sixth or eighth aspects, and includes a processor and a transceiver. The processor is configured to support the second device to perform corresponding functions in the above method. The transceiver is configured to support communication of the second device to receive or transmit information, frames or instructions in the above method. The second device may further include a memory. The memory is configured to be coupled to the processor and stores necessary program instructions and data for the second device.

[0173] According to a nineteenth aspect, the present application provides an apparatus, implemented in the form of a chip product, including an input / output interface and a processing circuit. The apparatus is a chip in a first device of the first, third, fifth or seventh aspects. The input / output interface is configured to receive or transmit information, frames or instructions in the aforementioned method. The processing circuit is configured to support the first device to perform corresponding functions in the aforementioned method.

[0174] According to a twentieth aspect, the present application provides an apparatus, implemented in the form of a chip product, including an input / output interface and a processing circuit. The apparatus is a chip in a second device of the second, fourth, sixth or eighth aspects. The input / output interface is configured to receive or transmit information, frames or instructions in the aforementioned method. The processing circuit is configured to support the second device to perform corresponding functions in the aforementioned method.

[0175] According to a twenty-first aspect, the present application provides a computer readable storage medium having stored thereon program instructions which, when executed on a computer, cause the computer to perform a method for recovering permission to use a transmission opportunity according to the first aspect, the third aspect, the fifth aspect or the seventh aspect. Alternatively, the program instructions, when executed on a computer, cause the computer to perform a method for recovering permission to use a transmission opportunity according to the second aspect, the fourth aspect, the sixth aspect or the eighth aspect.

[0176] According to a twenty-second aspect, the present application provides a computer program product comprising program instructions, which when the computer program product runs on a computer, causes the computer to perform a method for recovering permission to use a transmission opportunity according to the first aspect, the third aspect, the fifth aspect or the seventh aspect. Alternatively, when the computer program product runs on a computer, the computer performs a method for recovering permission to use a transmission opportunity according to the second aspect, the fourth aspect, the sixth aspect or the eighth aspect.

[0177] According to a twenty-third aspect, an embodiment of the present application provides a wireless communication system, the system including a first device according to the ninth, eleventh, thirteenth or fifteenth aspect, and a second device according to the tenth, twelfth, fourteenth or sixteenth aspect.

[0178] According to an embodiment of the present application, the first frame may indicate that the second device has stopped using the allocated time resource (first time resource). Therefore, the first device revokes / recovers the permission to use TXOP in advance based on the indication of the first frame. This can improve the channel resource utilization and the reliability of the recovery of the permission to use TXOP. [Brief description of the drawings]

[0179] [Figure 1a] 1 is a schematic diagram of the architecture of a communication system according to the present application;

[0180] [Figure 1b] FIG. 2 is a schematic diagram of the structure of an access point according to an embodiment of the present application;

[0181] [Figure 1c] 1 is a schematic diagram of a STA structure with a single antenna / radio frequency.

[0182] [Figure 2a]FIG. 1 is a schematic diagram of applying a single-user trigger frame to a P2P scenario.

[0183] [Figure 2b] FIG. 1 is a schematic diagram of applying a single-user trigger frame to a UL transmission scenario.

[0184] [Figure 2c] FIG. 2 is a schematic diagram of remaining duration.

[0185] [Diagram 3] 2 is a schematic flowchart of a transmission opportunity permission recovery method according to an embodiment of the present application;

[0186] [Figure 4] 2 is a schematic diagram of a structure of a first frame according to an embodiment of the present application;

[0187] [Diagram 5] FIG. 1 is a schematic diagram of an application scenario for recovering permission to use a TXOP in a UL scenario according to an embodiment of the present application.

[0188] [Figure 6] FIG. 1 is a schematic diagram of an application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application.

[0189] [Figure 7] FIG. 2 is another schematic diagram of a structure of a first frame according to an embodiment of the present application.

[0190] [Figure 8] FIG. 2 is another schematic diagram of a structure of a first frame according to an embodiment of the present application.

[0191] [Figure 9] FIG. 13 is a schematic diagram of another application scenario of recovering permission to use a TXOP in a UL scenario according to an embodiment of the present application.

[0192] [Figure 10] FIG. 13 is a schematic diagram of another application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application.

[0193] [Figure 11a] FIG. 2 is another schematic diagram of a structure of a first frame according to an embodiment of the present application.

[0194] [Figure 11b] FIG. 2 is another schematic diagram of a structure of a first frame according to an embodiment of the present application.

[0195] [Figure 12] FIG. 2 is a schematic diagram of a Frame Control field structure according to an embodiment of the present application;

[0196] [Figure 13] 1 is a schematic diagram of a scenario in which boundary crossing transmission of a SU END frame is allowed in a UL scenario according to an embodiment of the present application;

[0197] [Figure 14] 1 is a schematic diagram of a scenario in which boundary crossing transmission of a SU END frame is allowed in a P2P scenario according to an embodiment of the present application;

[0198] [Figure 15] FIG. 13 is a schematic diagram of another application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application;

[0199] [Figure 16] 4 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application;

[0200] [Figure 17]FIG. 1 is a schematic diagram of a scenario for restoring permission to use a TXOP based on a pre-configured duration T in a P2P scenario according to the present application.

[0201] [Figure 18] 4 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application;

[0202] [Figure 19] FIG. 1 is a schematic diagram of a scenario for restoring permission to use a TXOP based on a pre-configured duration T in a UL scenario according to the present application.

[0203] [Figure 20] 4 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application;

[0204] [Figure 21] FIG. 2 is a schematic diagram of the structure of an improved BA frame according to an embodiment of the present application.

[0205] [Figure 22] FIG. 2 is a schematic diagram of an application scenario in which a first device actively recovers permission to use a TXOP according to the present application.

[0206] [Diagram 23] FIG. 2 is another schematic diagram of an application scenario in which a first device actively recovers permission to use a TXOP according to the present application.

[0207] [Figure 24] FIG. 2 is another schematic diagram of an application scenario in which a first device actively recovers permission to use a TXOP according to the present application.

[0208] [Diagram 25] 1 is a schematic diagram of the structure of an apparatus 1 for recovering permission to use a transmission opportunity according to an embodiment of the present application;

[0209] [Figure 26] 1 is a schematic diagram of the structure of a communication device 1000 according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0210] The following clearly describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application.

[0211] In the description of this application, unless otherwise specified, " / " means "or." For example, A / B can represent A or B. The term "and / or" in this specification only describes the association relationship between related objects, and indicates that there are three possible relationships. For example, A and / or B can represent the following three cases: only A exists, both A and B exist, and only B exists. In addition, "at least one" means one or more, and "more than one" means two or more. Terms such as "first" and "second" do not limit the quantity or execution order, and terms such as "first" and "second" do not indicate clear differences.

[0212] In this application, words such as "example" and "for example" denote providing an example, illustration, or explanation. Any embodiment or design scheme described in this application as an "example" or "for example" should not be described as preferred or having more advantages over another embodiment or design scheme. Rather, use of the word "example" or "for example" is intended to present the relevant concept in a concrete manner.

[0213] The technical solutions provided in the present application may be applied to various communication systems, such as systems using the IEEE 802.11 standard. For example, the IEEE 802.11 standard includes, but is not limited to, the 802.11ax standard, the 802.11be standard, or the next generation 802.11 standard. Scenarios to which the technical solutions of the present application are applied include communication between an AP and one or more STAs, communication between APs, communication between STAs, etc. For example, FIG. 1a is a schematic diagram of an architecture of a communication system according to the present application. As shown in FIG. 1a, the communication system may include one AP and two STAs (e.g., STA1 and STA2 in FIG. 1a). The AP may communicate with STA1, or the AP may further communicate with STA2.

[0214] An access point (AP) in this application is a device with a wireless communication function, and supports communication based on a wireless local area network (WLAN) protocol. An access point may have a function of communicating with another device (e.g., a station or another access point) in a WLAN network. Of course, an access point may have a function of communicating with further other devices. In a WLAN system, an access point may be referred to as an access point station (AP STA). A device with a wireless communication function may be an entire device, or a chip or processing system mounted on the entire device. A device in which a chip or processing system is disposed may implement the method and functions in the embodiments of this application under the control of the chip or processing system. An AP in the embodiments of this application is a device that provides services for STAs, and may support 802.11 series protocols. For example, an AP may be a communication entity, such as a communication server, a router, a switch, or a bridge. An AP may include a macro base station, a micro base station, a relay station, etc. in various forms. Of course, an AP may alternatively be a chip or processing system within these devices in various forms to implement the method and functions in the embodiments of this application.

[0215] A station (STA) in this application is a device with wireless communication capability, supports communication based on a WLAN protocol, and has the capability of communicating with other stations or access points in a WLAN network. In a WLAN system, a station may be referred to as a non-access point station (non-AP STA). For example, a STA is any user communication device that allows a user to communicate with an AP and further with a WLAN. A device with wireless communication capability may be an entire device, or a chip or processing system mounted on the entire device. A device in which a chip or processing system is disposed may implement the methods and functions in the embodiments of this application under the control of the chip or processing system. For example, a STA may be a user device that can connect to the Internet, such as a tablet computer, a desktop computer, a laptop computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, a netbook, a personal digital assistant (PDA), a mobile phone, etc. Alternatively, the STA may be an Internet of Things node in the Internet of Things, an in-car communication device in the Internet of Vehicles, an entertainment device, a gaming device or system, a Global Positioning System device, etc. Alternatively, the STA may be a chip and processing system in the aforementioned terminals.

[0216] WLAN systems can provide high-speed and low-latency transmission. With the continuous evolution of WLAN application scenarios, WLAN systems will be applied to more scenarios and industries, such as the Internet of Things industry, Internet of Vehicles industry, banking industry, enterprise offices, stadium exhibition halls, concert halls, hotel rooms, dormitories, hospital wards, classrooms, supermarkets, squares, streets, production workshops, warehouses, etc. Of course, devices (e.g., access points or stations) supporting WLAN communication may be sensor nodes (e.g., smart water meters, smart electricity meters, or smart air detection nodes) in smart cities, smart devices (e.g., smart cameras, projectors, displays, televisions, stereos, refrigerators, washing machines, etc.) in smart homes, nodes in the Internet of Things, entertainment terminals (e.g., augmented reality (AR), virtual reality (VR), or other wearable devices), smart devices (e.g., printers, projectors, speakers, or stereos) in smart offices, Internet of Vehicles devices in the Internet of Vehicles, infrastructure in everyday life scenarios (e.g., vending machines, supermarket self-service navigation stations, self-service cashiers, or self-service ordering machines), devices in large sports and music venues, etc. The specific forms of STAs and APs are not limited in the embodiments of this application, and are merely examples for the purposes of description herein.

[0217] It should be understood that the 802.11 standard focuses on the physical layer (PHY) part and the media access control (MAC) layer part. For example, FIG. 1b is a schematic diagram of the structure of an access point according to an embodiment of the present application. The AP may have multiple antennas / radio frequencies or may have a single antenna / radio frequency. The antenna / radio frequency is used for transmitting and receiving data packets. In some implementations, the antenna or radio frequency part of the AP may be separated, i.e., located remotely from the main body of the AP. In FIG. 1b, the AP may include a physical layer processing circuit and a media access control processing circuit. The physical layer processing circuit may be configured to process physical layer signals, and the MAC layer processing circuit may be configured to process MAC layer signals. As another example, FIG. 1c is a schematic diagram of the structure of a station according to an embodiment of the present application. FIG. 1c is a schematic diagram of the structure of a STA with a single antenna / radio frequency. In a practical scenario, the STA may alternatively have multiple antennas / radio frequencies, and may be a device with more than two antennas. The antenna / radio frequency is used for transmitting and receiving data packets. In some implementations, the antenna or radio frequency portion of the STA may be separated, in other words, located remotely from the main body of the STA. In FIG. 1c, the STA may include a PHY processing circuit and a MAC processing circuit. The physical layer processing circuit may be configured to process physical layer signals, and the MAC layer processing circuit may be configured to process MAC layer signals.

[0218] In order to better understand the technical solution provided in this application, the following briefly describes an application scenario of the method for recovering permission to use a transmission opportunity provided in this embodiment of the present application.

[0219] The method of recovering permission to use a transmission opportunity provided in this embodiment of the present application may be applied to a point-to-point (or peer-to-peer, P2P) communication scenario, an uplink (UL) transmission scenario, etc., which is not limited here. The data transmission format used in the P2P scenario and the UL scenario in this embodiment of the present application is SU PPDU, etc., which is not limited here.

[0220] It should be understood that the trigger frame in the current IEEE 802.11ax standard is designed for multiple users to transmit uplink TB PPDUs simultaneously. Therefore, the current trigger frame needs to indicate information such as modulation and coding scheme (MCS), resource unit (RU), and transmission power. Since the AP usually has a stronger channel access function, the next generation IEEE 802.11be standard needs to support AP-triggered SU PPDU. Currently, to implement AP-triggered SU PPDU, an AP may transmit a single-user trigger frame to allocate a part of the time resource in the TXOP to an associated STA (for simplicity, hereinafter referred to as designated STA or target STA for short). The designated STA then communicates with another STA or AP in the allocated time resource. The communication between the designated STA and another STA may be understood as P2P communication or P2P transmission, and the communication between the designated STA and the AP may be understood as UL communication or UL transmission.

[0221] For example, FIG. 2a is a schematic diagram of applying a single-user trigger frame to a P2P scenario. As shown in FIG. 2a, after obtaining a TXOP, the AP may use a single-user trigger frame (e.g., a modified multi-user request to send (mMU-RTS) frame in FIG. 2a) to allocate some or all of the remaining time resource in the TXOP (e.g., the first time resource in FIG. 2a) to a designated STA (e.g., STA1 in FIG. 2a). In the following embodiments of the present application, the first time resource may be referred to as a single-user service period (SU SP). This is not limited here. The mMU-RTS frame may carry information about STA1, the remaining time resource of the TXOP, the duration of the first time resource allocated to STA1, and so on. Thus, in the allocated first time resource, STA1 may transmit a SU PPDU to STA2, and STA2 may transmit a block acknowledgement (BA) frame of the SU PPDU to STA1. In this embodiment of the present application, it is easy to understand that the start time of the first time resource is not earlier than the start time of the TXOP, and the end time of the first time resource is not later than the end time of the TXOP, i.e., the start time of the first time resource is equal to or greater than the start time of the TXOP, and the end time of the first time resource is equal to or less than the end time of the TXOP.

[0222] Optionally, the mMU-RTS frame may further carry information such as whether the designated STA needs to respond to a Clear to Send (CTS) frame. For example, see FIG. 2a. After STA1 receives the mMU-RTS frame sent by the AP, STA1 determines by parsing the mMU-RTS frame that the AP has assigned a first time resource to STA1 and requires STA1 to respond to a CTS frame before sending a SU PPDU. STA1 can first send a CTS frame in the assigned first time resource, send a SU PPDU to STA2, and then receive a BA frame of the SU PPDU returned by STA2 to STA1. It should be understood that in a P2P scenario, the AP can regain the permission to use TXOP only after the end of the first time resource. It may be understood that the AP regains the permission to use the TXOP, the AP may transmit a PPDU (PPDU shown in FIG. 2a) in the time period from the end of the first time resource to the end of the TXOP (Ts in FIG. 2a), allocate the PPDU to another STA, etc. This is specifically determined based on the actual application scenario and is not limited here.

[0223] For example, FIG. 2b is a schematic diagram of applying a single-user trigger frame to a UL transmission scenario. As shown in FIG. 2b, after obtaining a TXOP, the AP can use a single-user trigger frame (e.g., mMU-RTS frame in FIG. 2b) to allocate some or all of the remaining time resources in the TXOP (e.g., the first time resource in FIG. 2b) to a designated STA (e.g., STA1 in FIG. 2b). The mMU-RTS frame may carry information about STA1, the remaining time resources of the TXOP, the duration of the first time resource allocated to STA1, and so on. Thus, in the allocated first time resource, STA1 may transmit a SU PPDU to the AP, and the AP may transmit a BA frame of the SU PPDU to STA1. Optionally, if the mMU-RTS frame further carries information that the designated STA needs to respond to the CTS frame, after receiving the MU-RTS frame, STA1 needs to first transmit one CTS frame and then transmit a SU PPDU to the AP. It should be understood that in a UL transmission scenario, the AP can regain permission to use the TXOP only after the end of the first time resource, see for example Fig. 2b. The AP transmits a PPDU at the end of the first time resource.

[0224] It should be understood that if the duration of the first time resource allocated by the AP to the designated STA is long and the designated STA completes the required transmission after using the first time resource for a certain time period, the designated STA does not use the first time resource in the remaining time period. For example, FIG. 2c is a schematic diagram of the remaining duration. As shown in FIG. 2c, if the duration of the first time resource allocated by the AP to the designated STA (e.g., STA1 in FIG. 2c) is long and STA1 finishes all transmission at time t1 in FIG. 2c, the designated STA does not use the first time resource in the remaining time period (e.g., the time period from t1 to t2 in FIG. 2c). Optionally, if the duration of the first time resource allocated by the AP to the designated STA is short and the designated STA does not complete the required transmission after using the first time resource for a certain time period, but the remaining duration of the first time resource is not enough to transmit a complete SU PPDU, the designated STA does not use the first time resource in the remaining duration. It can be understood that in any case where the first time resource has a remaining duration, the remaining duration may cause a waste of channel resources and allow another STA to obtain permission to use the channel through contention during the remaining duration. However, the AP cannot recover the permission to use TXOP. Therefore, an embodiment of the present application provides a method for recovering the permission to use a transmission opportunity. In this method, the permission to use a transmission opportunity can be recovered in advance, improving the utilization rate of channel resources and the reliability of recovering the permission to use TXOP.

[0225] The following describes in detail the technical solutions provided in the present application with reference to further accompanying drawings.

[0226] It should be noted that in this application, the first device may be an AP, and the second device may be a non-access point station (i.e., a non-AP STA) or an access point AP. For ease of explanation, the following uses the first device and the second device as examples for explanation in this application.

[0227] In addition, it can be understood that both the first device and the second device in the present application support the 802.11be protocol (or Wi-Fi7, referred to as EHT protocol) and can further support other WLAN communication protocols, such as 802.11ax and 802.11ac protocols. It should be understood that the first device and the second device in the present application can further support the next generation protocol of the 802.11be protocol. That is, the method provided in the present application is applicable to the 802.11be protocol and the next generation protocol of the 802.11be protocol.

[0228] An embodiment of the present application provides a method for recovering permission to use a transmission opportunity, in which a first device can recover / revoke permission to use a TXOP by receiving a first frame transmitted by a second device and indicating a return of the TXOP.

[0229] Specifically, Figure 3 is a schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application. As shown in Figure 3, the method for recovering permission to use a transmission opportunity includes the following steps:

[0230] S101: A first device receives a first frame from a second device.

[0231] In some possible implementations, a first device may receive a first frame from a second device. The first frame indicates that the second device has stopped using the first time resource. It should be understood that the first time resource may be allocated by the first device to the second device from the acquired TXOP using a single-user trigger frame. Specifically, after acquiring the TXOP, the first device may immediately allocate some or all of the time resources in the TXOP to the second device using a single-user trigger frame. Alternatively, after acquiring the TXOP, the first device may use a portion of the time resource and then allocate some or all of the remaining time resources in the TXOP to the second device using one single-user trigger frame.

[0232] Generally, after the first time resource is allocated to the second device, the second device can use the first time resource to perform uplink single-user PPDU transmission or P2P communication. The single-user trigger frame may include a first field and a second field. The first field indicates the remaining time resource of the TXOP. Specifically, the first field is a duration field, and the second field indicates the first time resource. That is, the single-user trigger frame may carry information indicating the remaining duration of the TXOP and carry information indicating the first time resource. The single-user trigger frame in this embodiment of the present application may be designed based on or using a multi-user (MU) request to send (RTS) frame (for ease of explanation, in the following of the present application, the single-user trigger frame is referred to as a modified or improved MU-RTS frame or mMU-RTS frame). Alternatively, the single-user trigger frame may be a new type of trigger frame. This is specifically determined based on the actual application scenario, and is not limited in this application.

[0233] In some possible implementations, the first frame received by the first device from the second device may carry first indication information. The first indication information indicates that the second device has stopped using the first time resource. In a UL scenario, the first frame may be a quality of service data (QoS data) frame or a quality of service null data (QoS null data) frame. In a P2P scenario, the first frame may be a QoS null data frame. Both the QoS data frame and the QoS null data frame are MAC layer frames (i.e., MAC frames). When encapsulated at the physical layer, both the QoS data frame and the QoS null data frame need to be encapsulated into a SU PPDU for transmission. The QoS null data frame may be understood to be a special QoS data frame. That is, the QoS null data frame is a QoS data frame that does not carry service data. The service data may be voice data, video data, file data, etc., which is not limited in this application. It should be understood that both the QoS data frame and the QoS null data frame include an A-control field. The Control ID field in the A-control field indicates the control field type of the A-control field. For example, if the control identifier of the A-control field is 6 (i.e., the second value in this application), it indicates that the A-control field is specifically a CAS control field.

[0234] In some possible implementations, when the A control field is a CAS control field (i.e., when the control ID field in the A control field=6), the meaning of the value of the reverse grant (RDG) / more PPDU (RDG / More PPDU) subfield in the enhanced CAS control field may indicate that the second device has stopped using the first time resource. That is, when the A control field is a CAS control field, the first indication information is the RDG / more PPDU subfield in the CAS control field. "Enhanced" in this application may be understood as the meaning of the value of the RDG / more PPDU in the original standard protocol (i.e., the IEEE 802.11ax standard protocol) being modified / adjusted, so that the RDG / more PPDU subfield may indicate that the second device has stopped using the first time resource. In this embodiment of the application, the "RDG / more PPDU subfield" may alternatively be briefly described as "RDG subfield".

[0235] For clarity, FIG. 4 shows a schematic diagram of the structure of a first frame according to an embodiment of the present application. The first frame is a QoS data frame in an enhanced CAS control field. As shown in FIG. 4, the QoS data frame may include a Frame Control field, a Duration field, an Address 1 field, an Address 2 field, an Address 3 field, a Sequence Control field, an Address 4 field, a QoS Control field, an A-Control field, a Frame Body field, and a frame check sequence (FCS) field. The A-Control field includes 30 bits and may carry one or more control field types. Each control field type includes a 4-bit Control ID field and a control information field of a certain length. That is, one control ID may indicate one control field type, and the field length of the control information field corresponding to each control ID is fixed, but the control information fields corresponding to different control IDs may have different lengths. For example, as shown in FIG. 4, when the control identifier=6, it indicates that the A control field is a CAS control field. Specifically, in the CAS control field, the field length of the control information field is 8 bits. In the control information field in the CAS control field, the first bit indicates an access type constraint (AC Constraint) subfield, the second bit indicates a reverse acknowledgement / more PPDU (RDG / More PPDU) subfield, the third bit indicates a parameter-based spatial reuse transmission (PSRT PPDU) subfield, and the fourth bit to the eighth bit indicate a reserved field.

[0236] In the IEEE 802.11ax standard, the values ​​and associated meanings of the RDG / Further PPDU subfield in the CAS control field are shown in Table 1 below. [Table 1]

[0237] As shown in Table 1, the first column represents the value of the RDG / further PPDU subfield, the second column represents the identity / role of the STA that transmits the PPDU that includes the RGB / further PPDU subfield (i.e., the role of the transmitting STA), and the third column represents the specific meaning of those values. As shown in Table 1, if the role of the transmitting STA is not an RD responder, if the value of the RGB / further PPDU subfield is set to 0, it indicates that there is no reverse acknowledgement. If the role of the transmitting STA is an RD responder, if the value of the RGB / further PPDU subfield is set to 0, it indicates that the PPDU carrying the frame is the last transmission by the RD responder. Correspondingly, if the role of the transmitting STA is an RD initiator, if the value of the RGB / further PPDU subfield is set to 1, it indicates that there is a reverse acknowledgement. If the role of the transmitting STA is an RD responder, if the value of the RGB / further PPDU subfield is set to 1, it indicates that the PPDU carrying the frame is followed by another PPDU.

[0238] In the present application, it can be understood that in order to allow the RGB / further PPDU subfield in the enhanced CAS control field to instruct the second device to stop using the first time resource, the meaning of the value of the RGB / further PPDU subfield in the original CAS control field needs to be modified / enhanced based on Table 1. The values ​​and associated meanings of the RGB / further PPDU subfield in the enhanced CAS control field are shown in Table 2 below. [Table 2]

[0239] As shown in Table 2, the first column represents the value of the RGB / further PPDU subfield, the second column represents the identity / role of the STA that transmits the PPDU that includes the RGB / further PPDU subfield (i.e., the role of the transmitting STA), and the third column represents the specific meaning of those values. As shown in Table 2, the meaning of the value of the RGB / further PPDU subfield in the enhanced CAS control field is as follows: if the role of the transmitting STA is neither an RD responder nor a target STA in one SU SP, if the value of the RGB / further PPDU subfield is set to 0, it indicates that there is no reverse acknowledgement. If the role of the transmitting STA is an RD responder, if the value of the RGB / further PPDU subfield is set to 0, it indicates that the PPDU carrying the frame is the last transmission by the RD responder. If the role of the transmitting STA is a target STA in one SU SP, if the value of the RGB / further PPDU subfield is set to 0, it indicates that the PPDU carrying the frame is the last transmission by the target STA in the SU SP. Correspondingly, if the role of the sending STA is RD initiator, the value of the RGB / Further PPDU subfield is set to 1, which indicates the presence of a reverse acknowledgement. If the role of the sending STA is RD responder or target STA in one SU SP, the value of the RGB / Further PPDU subfield is set to 1, which indicates that the PPDU carrying the frame is followed by another PPDU.

[0240] "The PPDU carrying the frame is the last transmission by the target STA in the SU SP" should be understood as the target STA (i.e., the second device in this application) stopping using the first time resource. The first device is the allocator of the SU SP (i.e., the first time resource in this application), and specifically, the first device may use a single-user trigger frame to allocate the first time resource to the second device from the obtained transmission opportunity TXOP. Therefore, the first device knows the specific device that can use the first time resource. When the first device receives the first frame in the first time resource, it can be understood that the first device determines that the sender address of the first frame is the second device, and if the first device determines that the second device is the second device to which the first time resource is allocated (i.e., the second device is the designated STA / target STA), the first device parses the first frame. If the first device learns through parsing that the value of the RDG subfield in the CAS control field in the first frame is 0, it indicates that the PPDU carrying the frame is the last transmission by the target STA in the SU SP, that is, the first device can determine that the second device has stopped using the first time resource.

[0241] Optionally, to allow the RGB / Further PPDU subfield in the enhanced CAS control field to indicate that the second device has stopped using the first time resource, the values ​​and associated meanings of the RGB / Further PPDU subfield in the enhanced CAS control field are shown in Table 3 below. [Table 3]

[0242] As shown in Table 3, the first column represents the value of the RGB / further PPDU subfield, the second column represents the identity / role of the STA that transmits the PPDU including the RGB / further PPDU subfield (i.e., the role of the transmitting STA), and the third column represents the specific meaning of the value. As shown in Table 3, the meaning of the value of the RGB / further PPDU subfield in the enhanced CAS control field is as follows: if the role of the transmitting STA is neither an RD responder nor a target STA in one SU SP, if the value of the RGB / further PPDU subfield is set to 0, it indicates that there is no reverse acknowledgement. If the role of the transmitting STA is an RD responder, if the value of the RGB / further PPDU subfield is set to 0, it indicates that the PPDU carrying the frame is the last transmission by the RD responder. If the role of the transmitting STA is a target STA in one SU SP, if the value of the RGB / further PPDU subfield is set to 0, it indicates that the PPDU carrying the frame is followed by another PPDU. Correspondingly, if the role of the transmitting STA is an RD initiator, if the value of the RGB / further PPDU subfield is set to 1, it indicates that there is a reverse acknowledgement. If the role of the transmitting STA is RD responder, the value of the RGB / Further PPDU subfield set to 1 indicates that the PPDU carrying the frame is followed by another PPDU. If the role of the transmitting STA is target STA in one SU SP, the value of the RGB / Further PPDU subfield set to 1 indicates that the PPDU carrying the frame is the last transmission by the target STA in the SU SP.

[0243] "The PPDU carrying the frame is the last transmission by the target STA in the SU SP" should be understood as the target STA (i.e., the second device in this application) stopping to use the first time resource. Specifically, when the second device receives the first frame from the first device, if the second device determines that the first device is the target STA, the second device parses the first frame. If the first device learns through parsing that the value of the RDG subfield in the CAS control field in the first frame is 1, it indicates that the PPDU carrying the frame is the last transmission by the target STA in the SU SP. That is, the first device may determine that the second device has stopped using the first time resource. Therefore, the first device may restore the permission to use TXOP.

[0244] For the sake of clarity, Fig. 5 shows a schematic diagram of an application scenario of recovering permission to use TXOP in a UL scenario according to an embodiment of the present application. As shown in Fig. 5, in a UL scenario, the process from when a first device (e.g., AP in Fig. 5) transmits an mMU-RTS frame to when a second device (e.g., STA1 in Fig. 5) transmits a SU PPDU to a SU PPDU receiver (e.g., AP in Fig. 5) in a first time resource (e.g., SU SP in Fig. 5) can be referred to the process described in Fig. 2b. Details are not described again here. When STA1 transmits the last SU PPDU to the AP in the SU SP and an enhanced CAS control field is carried in the SU PPDU, the RDG subfield (i.e., RGB / further PPDU subfield) in the CAS control field in the SU PPDU may indicate to the AP that the current SU PPDU is the last SU PPDU transmitted in the SU SP. Thus, after receiving the SU PPDU carrying the enhanced CAS control field, the AP may respond with a BA frame to STA1 at or after a Short Inter-frame Space (SIFS) has elapsed, and then regain permission to use the TXOP when the SIFS has elapsed. It can be understood that if the SU PPDU carrying the enhanced CAS control field does not require the AP to respond to the BA frame, the AP may regain permission to use the TXOP (e.g., the AP transmits the PPDU of FIG. 5) when the SIFS has elapsed after receiving the SU PPDU carrying the enhanced CAS control field. The last SU PPDU is the SU PPDU encapsulated with the QoS data frame.

[0245] For ease of understanding, Fig. 6 shows a schematic diagram of an application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application. As shown in Fig. 6, in a P2P scenario, the process from when a first device (e.g., AP in Fig. 6) transmits an mMU-RTS frame to when a second device (e.g., STA1 in Fig. 6) transmits a SU PPDU to a SU PPDU receiver (e.g., STA2 in Fig. 6) in a first resource (e.g., SU SP in Fig. 6) can be referred to the process described in Fig. 2a. Details are not described again here. When STA1 transmits the last SU PPDU to STA2 in SU SP, if STA1 successfully receives a BA frame transmitted by STA2, STA1 can transmit a QoS null data frame carrying an improved CAS control field to the AP when SIFS has elapsed after receiving the BA frame to indicate to the AP that STA1 stops using the SU SP. It should be understood that the QoS null data frame is also transmitted in a SU PPDU format. Thus, after receiving a SU PPDU encapsulated with a QoS null data frame in the enhanced CAS control field, the AP may regain permission to use the TXOP as soon as a SIFS has elapsed (e.g., the AP sends the PPDU of Figure 6).

[0246] Optionally, in some possible implementations, a new A-Control field may be further designed to indicate that the second device stops using the first time resource when the first frame is a QoS data frame or when the first frame is a QoS null data frame. For example, FIG. 7 shows a schematic diagram of a structure of a first frame according to an embodiment of the present application. As shown in FIG. 7, the QoS data frame may include a Frame Control field, a Duration field, an Address 1 field, an Address 2 field, an Address 3 field, a Sequence Control field, an Address 4 field, a QoS Control field, an A-Control field, a Frame Body field, and a Frame Check Sequence (FCS) field. The A-Control field includes 30 bits and may carry one or more control field types. Each control field type includes a 4-bit Control ID field and a control information field of a certain length. That is, one control ID may indicate one control field type, and the field length of the control information field corresponding to each control ID is fixed, but the control information fields corresponding to different control IDs may have different lengths. In this embodiment of the present application, it can be understood that when a new A control field is designed, the length of the control information field in the new A control field can be designed to be 8 bits. In the 8 bits included in the control information field, at least one bit may be set to indicate a single-user end (SU END) subfield, and another bit different from the single-user end subfield indicates a reserved subfield.As shown in FIG. 7, in the 8 bits included in the control information field, the first bit may be used to indicate a single-user end (SU END) subfield, and the second to eighth bits may be used to indicate reserved subfields. When the value of the control identifier is the first value (for example, when the control identifier=7), the first value indicates that the A control field includes the first indication information. It may be understood that the control identifier in the new A control field may be set as another identifier that is not used in the standard protocol. For example, the control identifier in the new A control field may be further set to 8 to indicate that the control field is a new type of A control field. This is specifically determined based on the actual application scenario and is not limited here. Optionally, when the new A control field is designed, the length of the control information field in the new A control field may be designed to be 0 bits. That is, the new A control field does not include a control information field. This is not limited here.

[0247] It can be understood that when the new A-control field indicates to the second device to stop using the first time resource, the first indication information may be a control ID field in the A-control field (i.e., if the control information field in the new A-control field is designed to be 0 bits, it indicates that the new A-control field does not include a control information field. Therefore, carrying a control ID itself means carrying the first indication information). Alternatively, the first indication information may be a control ID field and a control information field in the A-control field (i.e., if the control information field in the new A-control field is designed to be non-zero bits, it indicates that the new A-control field includes a control information field. Therefore, the control ID field and the control information field jointly indicate the function of the new control field). Specifically, when the first device receives a first frame from the second device, if the first device parses the first frame and obtains through parsing that the value of the control ID field in the A-control field of the first frame is a first value, the second device may decide to stop using the first time resource based on the first value. Alternatively, when the first device receives a first frame from the second device, if the first device parses the first frame and obtains through parsing that the value of the control ID field in the A-control field of the first frame is a first value and the control information in the A-control field includes information indicating that the first frame is a return frame (i.e., a single-user end subfield), the second device may decide to stop using the first time resource based on the first value and the value of the single-user end subfield in the control information.

[0248] Optionally, in some possible implementations, the first indication information in the A-control field of an existing type of frame (e.g., a QoS data frame or a QoS null data frame) is used to indicate that the second device has stopped using the first time resource. Furthermore, a dedicated control frame may be designed to indicate that the TXOP is restored (i.e., the second device has stopped using the first time resource). In this application, the dedicated control frame may be referred to as a single user end (SU END) frame, a time resource return frame, etc. This is not limited in this application. That is, the first frame in this application may alternatively be a new type of frame, which indicates to the second device that it returns permission to use the TXOP. Specifically, the frame type field in the first frame indicates that the first frame is a control frame, and the frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource.

[0249] For example, FIG. 8 is another schematic diagram of a structure of a first frame according to an embodiment of the present application. As shown in FIG. 8, the first frame (i.e., the SU END frame in FIG. 8) may include a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a frame check sequence (FCS) field, etc. The Frame Control field includes a Protocol Version field, a Frame Type field, and a Frame Subtype field. When the value of the Frame Type field is 01, it indicates that the frame is a control frame, and the Frame Subtype field indicates that the first frame is a time resource return frame. As shown in FIG. 8, the value of the Frame Subtype field may be set to 1111, indicating that the frame is a SU END frame or a time resource return frame. It may be understood that the specific value of the Frame Subtype field is not limited in the present application. For example, the value of the Frame Subtype field may alternatively be 0000, 0001, 0010, or 1111. This is not a limitation of this application.

[0250] For the sake of clarity, Fig. 9 shows a schematic diagram of another application scenario of recovering permission to use TXOP in a UL scenario according to an embodiment of the present application. As shown in Fig. 9, in a UL scenario, the process from the time when a first device (e.g., AP in Fig. 9) transmits an mMU-RTS frame to the time when a second device (e.g., STA1 in Fig. 9) transmits a SU PPDU to a SU PPDU receiver (e.g., AP in Fig. 9) in a first time resource (e.g., SU SP in Fig. 9) can be referred to the process described in Fig. 2b. Details will not be described again here. Assume that the time when STA1 completes the transmission of the last SU PPDU to be transmitted and completes the reception of the BA frame of the SU PPDU is the time t1 shown in Fig. 9, the end of the SU SP is the time t2 shown in Fig. 9, and the duration of transmitting a SU END frame by the STA is Tsu_end. Therefore, if STA1 determines that t1+SIFS+Tsu_end≦t2, STA1 may transmit a SU END frame to the AP at time t1+SIFS. When SIFS has elapsed after receiving the SU END frame, the AP regains the permission to use the TXOP. The specific value of Tsu_end may generally be determined based on the modulation and coding scheme, spatial stream, bandwidth, and the corresponding duration of transmitting the SU END frame in the PPDU format. This is not limited here.

[0251] For the sake of clarity, Fig. 10 shows a schematic diagram of another application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application. As shown in Fig. 10, in a P2P scenario, the process from when a first device (e.g., AP in Fig. 10) sends an mMU-RTS frame to when a second device (e.g., STA1 in Fig. 10) sends a SU PPDU to a SU PPDU recipient (e.g., STA2 in Fig. 10) in a first time resource (e.g., SU SP in Fig. 10) can be referred to the process described in Fig. 2a. Details are not described again here. Suppose the end time of the SU PPDU used by STA1 is t1, the end time of the SU SP is t2, and the duration of sending a SU END frame by the STA is Tsu_end. Therefore, if STA1 determines that t1+SIFS+Tu_end≦t2, STA1 may send a SU END frame to the AP at the time of t1+SIFS. When SIFS has elapsed after receiving the SU END frame, the AP regains the permission to use the TXOP. The specific value of Tsu_end can generally be determined based on the duration of transmitting the SU END frame in the modulation and coding scheme, spatial stream, bandwidth, and PPDU format. This is not limited here.

[0252] Optionally, in some possible implementations, in addition to the first indication information, the first frame may further carry second indication information. The second indication information indicates whether the second device needs more time resources for data transmission. If the first frame is a QoS data frame or a QoS null data frame, and the A-control field in the QoS data frame or the QoS null data frame is a CAS control field, the first indication information may be an RDG subfield in the CAS control field, and the second indication information may be at least one bit in the fourth to eighth bits in the CAS control field. If the first frame is a QoS data frame or a QoS null data frame, and the A-control field in the QoS data frame or the QoS null data frame is a new A-control field, the first indication information may be a control identifier of the new A-control field, and the second indication information may be at least one bit in the second to eighth bits in the control information field in the new A-control field. If the first frame is a SU END frame (i.e., the first frame is a control frame for), the first indication information may be a frame subtype field in the frame control field, and the second indication information may be at least one reserved field selected from the reserved fields in the frame control field, etc. This is not limited thereto.

[0253] For ease of understanding, the following uses an example in which the first frame is a QoS data frame and the A-control field in the QoS data frame is a CAS control field to describe the first indication information and the second indication information. FIG. 11(a) is another schematic diagram of the structure of the first frame according to an embodiment of the present application. As shown in FIG. 11(a), when the control identifier=6, it indicates that the A-control field is a CAS control field. Specifically, in the control information field in the CAS control field, the first bit indicates an Access Type Constraint (AC Constraint) subfield, the second bit indicates a Reverse Authorization / More PPDU (RDG / More PPDU) subfield, the third bit indicates a Parameter-Based Spatial Reuse Transmission (PSRT PPDU) subfield, and the fourth to eighth bits indicate a Reserved field. Therefore, in this embodiment of the present application, at least one bit in the fourth to eighth bits indicates whether the second device further requires time resources to be used for data transmission. That is, in the present application, at least one bit of the reserved field may be used as a request field to request time resources again. For example, a one-bit reserved field (e.g., the fourth bit in FIG. 11(a)) is used as the request field. If the request field is set to 1, it may indicate that the second device further needs SU SP, and therefore requests the AP to continue allocating the time resource to the second device thereafter. If the request field is set to 0, it indicates that the second device no longer needs SU SP. Optionally, it may be further specified that if the request field is set to 0, it indicates that the second device further needs SU SP, and therefore requests the AP to continue allocating the time resource to the second device thereafter. If the request field is set to 1, it indicates that the second device no longer needs SU SP. This is specifically determined based on the actual application scenario and is not limited here.It should be understood that when the 1-bit reserved field is used as the request field, the request field can alternatively be any 1-bit in the 4th to 8th bits in the CAS control field, which is specifically determined based on the actual application scenario and is not limited here.

[0254] As another example, Figure 11(b) is another schematic diagram of the structure of the first frame according to an embodiment of the present application. As shown in Figure 11(b), when the A control field is a CAS control field, in the control information field in the CAS control field, the first bit indicates an Access Type Constraint (AC Constraint) subfield, the second bit indicates a Reverse Authorization / More PPDU (RDG / More PPDU) subfield, the third bit indicates a Parameter-Based Spatial Reuse Transmission (PSRT PPDU) subfield, and the fourth to eighth bits indicate a Reserved field. When the two-bit reserved field (e.g., the fourth and fifth bits in Figure 11(b)) is used as a request field, if the value of the request field is 00 (i.e., the value of the fourth bit is 0 and the value of the fifth bit is 0), it may indicate that the STA does not require a SU SP (i.e., the STA does not require a SU SP for UL transmission and does not require a SU SP for P2P transmission). When the value of the request field is 01 (i.e., the value of the fourth bit is 0 and the value of the fifth bit is 1), the request field may indicate a SU SP for UL transmission by the STA (i.e., the STA needs a SU SP for UL transmission and does not need a SU SP for P2P transmission). When the value of the request field is 10 (i.e., the value of the fourth bit is 1 and the value of the fifth bit is 0), the request field may indicate that the STA needs a SU SP for P2P transmission (i.e., the STA needs a SU SP for P2P transmission and does not need a SU SP for UL transmission). When the value of the request field is 11 (i.e., the value of the fourth bit is 1 and the value of the fifth bit is 1), the request field may indicate that the STA needs a SU SP for both UL transmission and P2P transmission (i.e., the STA needs a SU SP for both UL transmission and P2P transmission). It may be understood that the specific meanings indicated by different values ​​may be determined based on the actual application scenario. This is not limited here.

[0255] Optionally, when the 2-bit reserved field is used as the request field, the request field may alternatively be any two consecutive bits among the 4th through 8th bits in the CAS control field (e.g., the 4th and 5th bits, the 5th and 6th bits, the 6th and 7th bits, the 7th and 8th bits). Optionally, when the 2-bit reserved field is used as the request field, the request field may alternatively be any two non-consecutive bits among the 4th through 8th bits in the CAS control field. Any two non-consecutive bits may be two bits separated by one bit, e.g., the 4th and 6th bits, or the 5th and 7th bits, or the 6th and 8th bits. Optionally, any two non-consecutive bits may alternatively be two bits separated by two bits, e.g., the 4th and 7th bits, or the 5th and 8th bits. Optionally, any two non-consecutive bits may be two bits separated by three bits, for example, the fourth bit and the eighth bit, which is not limited here.

[0256] Optionally, in some possible implementations, regardless of P2P or UL scenarios, the protocol of the 802.11 standard specifies that the second device can transmit the SU PPDU carrying the service data only within the duration of the first time resource. Here, transmitting the SU PPDU carrying the service data only within the duration of the first time resource includes: completing the transmission of the SU PPDU before the end of the first time resource and transmitting a BA frame that requires a response. Thus, for the UL scenario, if the first frame is a QoS data frame (the QoS data frame is a QoS data frame carrying an enhanced CAS control field or a QoS data frame carrying a new A control field), the QoS data frame still needs to complete the transmission before the end of the first time resource. If the first frame is a frame that does not carry service data (i.e., the first frame is not a QoS data frame), it may be specified that the first frame may be allowed to exceed the end of the first time resource, i.e., boundary crossing transmission is allowed. For example, in a P2P or UL scenario, if the first frame is a SU END frame, the transmission of the SU END frame may be allowed to exceed the end of the first time resource, i.e., the end of the SU END frame may be allowed to be later than the end of the first time resource, and the start of the SU END frame may be earlier than the end of the first time resource. As another example, in a P2P scenario, if the first frame is a QoS Null data frame, the transmission of the QoS Null data frame may also be allowed to exceed the end of the first time resource, i.e., the end of the QoS Null data frame may be allowed to be later than the end of the first time resource, and the start of the QoS Null data frame may be earlier than the end of the first time resource.

[0257] For the sake of clarity, Fig. 13 shows a schematic diagram of a scenario in which boundary crossing transmission of SU END frame is allowed in a UL scenario according to an embodiment of the present application. As shown in Fig. 13, in a UL scenario, the process from the time when a first device (e.g., AP in Fig. 13) transmits an mMU-RTS frame to the time when a second device (e.g., STA1 in Fig. 13) transmits a SU PPDU to a SU PPDU receiver (e.g., AP in Fig. 13) in a first time resource (e.g., SU SP in Fig. 13) can be referred to the process described in Fig. 2b. Details are not described again here. After STA1 completes the transmission of the last SU PPDU in the first time resource and successfully receives a BA frame transmitted by the AP, if the end time of the first time resource has not been exceeded when SIFS has elapsed after STA1 receives the BA frame, STA1 immediately transmits one SU END frame to the AP, indicating that STA1 stops using the first time resource. The first device (eg, the AP in FIG. 13) regains permission to use the TXOP immediately when a SIFS has elapsed after receiving the SU END frame.

[0258] Optionally, Figure 14 is a schematic diagram of a scenario in which boundary crossing transmission of SU END frame is allowed in a P2P scenario according to an embodiment of the present application. As shown in Figure 14, in a P2P scenario, the process from the time when a first device (for example, AP in Figure 14) transmits an mMU-RTS frame to the time when a second device (for example, STA1 in Figure 14) transmits a SU PPDU to a SU PPDU receiver (for example, STA2 in Figure 14) in a first resource (for example, SU SP in Figure 14) can be referred to the process described in Figure 2a. Details are not described again here. After STA1 completes the transmission of the last SU PPDU in the first time resource and successfully receives the BA frame transmitted by STA2, if the end time of the first time resource has not passed when SIFS has elapsed after STA1 receives the BA frame, STA1 immediately transmits one SU END frame to the AP, indicating to the AP that STA1 stops using the first time resource. When a SIFS has elapsed after receiving a SU END frame, the AP immediately regains permission to use the TXOP.

[0259] Optionally, Figure 15 shows a schematic diagram of another application scenario of recovering permission to use TXOP in a P2P scenario according to an embodiment of the present application. As shown in Figure 15, in a P2P scenario, the process from the time when a first device (e.g., AP in Figure 15) sends an mMU-RTS frame to the time when a second device (e.g., STA1 in Figure 15) sends a SU PPDU to a SU PPDU receiver (e.g., STA2 in Figure 15) in a first time resource (e.g., SU SP in Figure 15) can be referred to the process described in Figure 2a. Details will not be described again here. After STA1 completes the transmission of the last SU PPDU in SU SP and successfully receives a BA frame sent by STA2, if the end time of SU SP has not passed when SIFS has elapsed after STA1 receives the BA frame, STA1 immediately sends one QoS null data frame to AP to indicate the end of the use of SU SP to AP. The AP regains permission to use the TXOP as soon as a SIFS has elapsed after receiving a QoS Null Data frame.

[0260] In this embodiment of the present application, the first frame may be a frame carrying a frame control field, and the second device indicates whether to stop using the first time resource by using a further data subfield in the frame control. If the further data subfield is set to 1, it indicates to stop using the first time resource, and if the further data subfield is set to 0, it indicates not to stop using the first time resource. In another example, if the further data subfield is set to 0, it indicates to stop using the first time resource, and if the further data subfield is set to 1, it indicates not to stop using the first time resource.

[0261] The structure of the frame control field is shown in Figure 12. In a frame transmitted by an AP to a station supporting power saving, there is currently a further data subfield, which indicates whether the AP buffers further data for a target STA. If the further data subfield is set to 1, it indicates that there is further buffered data. If the further data subfield is set to 0, it indicates that there is no further buffered data. Similarly, a TDLS station may use the further data subfield to indicate whether it has further buffered data for a TDLS receiving station in power saving mode. In the prior art, the further data subfield is not used in a scenario where a non-AP STA transmits to an associated AP, and the further data subfield is set to 0.

[0262] Specifically, in one possible implementation, the first device is an AP, and the second device may include two cases: one is a non-AP STA associated with the first device, and the other is an Overlapping Basic Service Set (OBSS) AP.

[0263] If the second device is a non-AP STA associated with the first device, in the technical solution in this embodiment of the present application, the further data subfield is used in a frame transmitted by the non-AP STA to the associated AP to indicate whether to stop using the first time resource. In this case, if the further data subfield is set to 0, it does not indicate that the non-AP STA does not use the further data subfield, but indicates that it does not stop using the first time resource. If the non-AP STA transmits to a station different from the associated AP, the value of the further data subfield does not indicate information indicating whether to stop using the first time resource. In this scenario, the specific meaning of the value of the further data subfield may conform to the function of indicating whether there is buffered data in the existing protocol, or may be redefined. This is not limited in this application. The station different from the associated AP may be a non-AP STA or may be the AP. This is not limited here in this application.

[0264] When the second device is an OBSS AP, in the technical solution in this embodiment of the present application, the further data subfield is used in a frame transmitted by the OBSS AP to the first device to indicate whether to stop using the first time resource. For example, when the further data subfield is set to 0, it indicates not to stop using the first time resource. When the OBSS AP transmits to a station different from the first device, the value of the further data subfield does not indicate information indicating whether to stop using the first time resource. In this scenario, the specific meaning of the value of the further data subfield may conform to the function of indicating whether there is buffered data in the existing protocol, or may be redefined. This is not limited in the present application. The station different from the first device may be a non-AP STA, or may be an AP. This is not limited in the present application.

[0265] It should be noted that the further data subfield may also indicate whether to stop using the first time resource, and since such functionality is different from the original functionality of the further data subfield, the further data subfield may have a different name, e.g., More Data / TXOP Sharing Termination. It should be noted that whether the name is modified does not affect the use of the functionality of the further data subfield.

[0266] In this technical solution, the existing further data subfield indicates whether to stop using the first time resource, thereby maximizing the use of existing fields in the further data subfield and no new fields are added additionally, which can reduce the indication overhead and aid product implementation.

[0267] S102: The first device recovers permission to use the TXOP based on the first frame.

[0268] In some possible implementations, upon receiving the first frame from the second device, the first device may obtain the first indication information carried in the first frame by parsing the first frame, and further recover the permission to use the TXOP based on the first indication information. Optionally, when the first device receives the first frame from the second device, if the first device obtains the first indication information and the second indication information carried in the first frame by parsing the first frame, the first device may recover the permission to use the TXOP based on the first indication information, and continue to allocate new time resources to the second device from the remaining duration of the TXOP based on the second indication information.

[0269] In this embodiment of the present application, the first frame indicates that the second device has stopped using the allocated time resource (first time resource), so that the first device revokes or restores the permission to use TXOP in advance based on the indication of the first frame, which can improve the utilization rate of the channel resource and the reliability of the restoration of the permission to use TXOP.

[0270] In addition, an embodiment of the present application further provides a method for recovering permission to use a transmission opportunity. This embodiment of the present application mainly describes that, when the standard protocol does not allow the transmission and reception of any frame beyond the end of the first time resource, the first device can recover or revoke the permission to use a TXOP by setting a preset duration T (i.e., a time threshold T).

[0271] Specifically, Figure 16 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application. As shown in Figure 16, the method for recovering permission to use a transmission opportunity includes the following steps:

[0272] S201: The first device receives a second frame.

[0273] In some possible implementations, when receiving the second frame at any time in the first time resource, the first device may further determine whether to recover the permission to use TXOP in advance based on the value relationship between the preset duration T and the duration between the end time of the second frame and the end time of the first time resource. That is, the first device needs to determine in real time whether the received second frame meets the condition for recovering the permission to use TXOP. The second frame may be a frame whose destination address (also called receiver address) is the address of the second device, or the second frame may be a frame whose sender address is the address of the second device and does not require an acknowledgement frame.

[0274] For example, in a P2P scenario, the second frame received by the first device and whose destination address is the address of the second device may be a BA frame sent by a SU PPDU receiver (i.e., another station STA) to the second device. As shown in Fig. 17, STA1 sends a SU PPDU to STA2, and STA2 responds to STA1 with a BA frame. That is, the destination address of the BA frame is STA1 (correspondingly understood as the second device in this embodiment of the present application), and the BA frame can also be correspondingly understood as the second frame in this embodiment of the present application. In a WLAN system, since the communication manner between devices is broadcast, the first device (e.g., AP in Fig. 17) may receive a BA frame sent by a SU PPDU receiver (e.g., STA2 in Fig. 17) to the second device. Optionally, in a P2P scenario, the second frame received by the first device and whose sender address is the address of the second device may be a SU PPDU that does not request a BA frame and is sent by the second device to the SU PPDU receiver. Alternatively, the second frame may be a management frame sent by the second device, etc. This is specifically determined based on the actual application scenario, and is not limited here.

[0275] For example, in the UL scenario, the first device receives a second frame whose sender address is the address of the second device, and the second frame does not request a response frame. For example, the second frame may be a SU PPDU sent by the second device to the first device, which does not request a BA frame. Alternatively, the second frame may be a management frame sent by the second device, etc. This is not limited here. Optionally, in the UL scenario, since the first device is the recipient of the SU PPDU, the first device may further determine whether to revoke the permission to use the TXOP by using the duration between the end of the BA frame sending the SU PPDU and the end of the first time resource.

[0276] S202: The first device recovers the permission to use the TXOP when the duration between the end of the second frame and the end of the first time resource is shorter than the preset duration T.

[0277] In some possible implementations, after the first device receives the second frame, if the first device determines that the duration between the end of the second frame and the end of the first time resource is shorter than the preset duration T, the first device recovers the permission to use the TXOP. Conversely, if the first device determines that the duration between the end of the second frame and the end of the first time resource is longer than the preset duration T, the first device does not recover the permission to use the TXOP.

[0278] Specifically, in a P2P scenario, when the first device receives an acknowledgement frame at any time in the first time resource, if the first device determines that the destination address of the acknowledgement frame is the address of the designated STA of the first time resource (i.e., the address of the second device), the first device may determine whether the duration between the end of the acknowledgement frame and the end of the first time resource is less than T. If the duration is less than T, the first device regains the permission to use the TXOP immediately after a SIFS. Conversely, if the duration is greater than T, the first device does not regain the permission to use the TXOP. Alternatively, when the first device receives a frame that does not request a response frame at any time in the first time resource, if the sender address of the frame that does not request a response frame is the address of the designated STA of the first time resource (i.e., the address of the second device), the first device determines whether the duration between the end of the frame and the end of the first time resource is less than T. If the duration is less than T, the first device may regain permission to use the TXOP immediately after a SIFS. Conversely, if the duration is greater than T, the first device does not regain permission to use the TXOP.

[0279] Specifically, in a UL scenario, when the first device receives a frame that does not require a response frame at any time in the first time resource, if the sender address of the frame that does not require a response frame is the address of the designated STA of the first time resource (i.e., the address of the second device), the first device determines whether the duration between the end of the frame and the end of the first time resource is less than T. If the duration is less than T, the first device can regain permission to use the TXOP immediately after a SIFS. Conversely, if the duration is greater than T, the first device does not regain permission to use the TXOP.

[0280] For the sake of clarity, Fig. 17 shows a schematic diagram of a scenario of recovering permission to use TXOP based on a preset duration T in a P2P scenario according to the present application. As shown in Fig. 17, in a P2P scenario, the process from when a first device (e.g., AP in Fig. 17) sends an mMU-RTS frame to when a second device (e.g., STA1 in Fig. 17) sends a SU PPDU to a SU PPDU recipient (e.g., STA2 in Fig. 17) in a first time resource (e.g., SU SP in Fig. 17) can be referred to the process described in Fig. 2a. Details will not be described again here. When an AP receives one BA frame at any time in the first time resource, and the destination address of the BA frame is the address of STA1, if the AP determines that the duration between the end of the BA frame and the end of the SU SP (e.g., T' in Fig. 17) is shorter than the preset duration T, the AP can recover permission to use TXOP immediately after a SIFS. Conversely, if T' is greater than T, the AP does not restore the permission to use the TXOP. Correspondingly, if STA1 receives a BA frame at any time in the first time resource and determines that the duration T' between the end of the BA frame and the end of the SU SP is less than T, STA1 defaults to considering that the AP restores the permission to use the TXOP, i.e., the STA is no longer allowed to transmit SU PPDUs for the remaining duration of the SU SP. Conversely, if STA1 determines that the duration T' is greater than T, the STA can continue to use the SU SP.

[0281] Optionally, in some possible implementations, after the first device determines that the duration between the end of the second frame and the end of the first time resource is equal to the preset duration T, the first device may choose to recover the permission to use TXOP. Alternatively, the first device may choose not to recover the permission to use TXOP. This is specifically determined based on the actual application scenario and is not limited here.

[0282] Correspondingly, the second device will no longer transmit PPDUs if the duration from the end of the second device receiving the second frame to the end of the first time resource is shorter than the preset duration T, or the duration from the end of the second device transmitting the second frame to the end of the first time resource is shorter than the preset duration T. Conversely, the second device may continue to use the first time resource if the duration from the end of the second device receiving the second frame to the end of the first time resource is longer than the preset duration T, or the duration from the end of the second device transmitting the second frame to the end of the first time resource is longer than the preset duration T.

[0283] Specifically, in a UL scenario or a P2P scenario, when the second device receives one acknowledgement frame at any time in the first time resource, the second device can determine whether the duration between the end of the acknowledgement frame and the end of the first time resource is less than T. If the duration is less than T, the second device defaults to considering that the first device recovers the permission to use TXOP, i.e., the second device is no longer allowed to transmit SU PPDUs in the remaining duration of the first time resource. Conversely, if the duration is longer than T, the STA may continue to use SU SP. Alternatively, when the second device transmits one frame that does not request a response frame at any time in the first time resource, the second device determines whether the duration between the end of the response frame and the end of the first time resource is less than T. If the duration is less than T, the second device defaults to considering that the first device recovers the permission to use TXOP, i.e., the second device is no longer allowed to transmit SU PPDUs in the remaining duration of the first time resource. Conversely, if the duration is greater than T, the second device may continue to use the first time resource.

[0284] It may be understood that whether the second device chooses to continue using the first time resource should be consistent with whether the first device chooses to recover the permission to use the TXOP when the duration between the end of the second device receiving the second frame and the end of the first time resource is equal to the preset duration T or the duration between the end of the second device transmitting the second frame and the end of the first time resource is equal to the preset duration T. For example, if it is specified that the first device chooses to recover the permission to use the TXOP when the first device determines that the duration between the end of the second frame and the end of the first time resource is equal to the preset duration T, the second device should choose not to transmit a PPDU frame when the duration between the end of the second frame and the end of the first time resource is equal to the preset duration T. Correspondingly, if it is specified that the first device elects to not restore permission to use the TXOP when the first device determines that the duration between the end of the second frame and the end of the first time resource is equal to the preset duration T, the second device may be specified to elect to continue using the first time resource when the duration between the end of the second frame and the end of the first time resource is equal to the preset duration T.

[0285] Optionally, in some possible implementations, if the second frame is the last SU PPDU transmitted by the second device when the second device uses the first time resource, or if the second frame is the BA frame of the last SU PPDU transmitted by the second device when the second device uses the first time resource, if the second device determines that the duration between the end of the second frame and the end of the first time resource is longer than the preset duration T, in order to prevent the channel resource from being wasted, the second device may further transmit a first frame to the first device to indicate that the second device has stopped using the first time resource. Correspondingly, the first device may receive the first frame from the second device and parse the information about the first frame, so that the first device may recover the permission to use TXOP based on the first frame. In this embodiment of the present application, for the solution in which the second device transmits the first frame to indicate that the second device has stopped using the first time resource, please refer to the process described in embodiment 1. The details will not be explained again here.

[0286] In this embodiment of the present application, in a P2P and UL scenario, the first device can determine the value relationship between the time threshold (i.e., the preset duration T in this application) and the duration T' between the end point at which the second frame is received at any time and the end point of the first time resource to determine whether to restore or revoke the permission of the first device to use TXOP. According to the solution in this embodiment of the present application, when T' is less than T, the permission to use TXOP is restored, and the permission to use TXOP can also be restored in advance. This can improve the utilization rate of channel resources and the reliability of restoring the permission to use TXOP.

[0287] Furthermore, in a UL scenario, the first device may alternatively transmit a second frame and determine whether to restore or revoke the permission to use the TXOP of the first device based on a value relationship between a time threshold (i.e., a pre-configured duration T in this application) and a duration T' between the end of the second frame and the end of the first time resource.

[0288] Specifically, Figure 18 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application. As shown in Figure 18, the method for recovering permission to use a transmission opportunity includes the following steps:

[0289] S301: The first device transmits a second frame.

[0290] In some possible implementations, in the UL scenario, the first device may alternatively send a second frame to the second device and determine whether to recover the permission to use the TXOP based on a value relationship between a preset duration T and a duration between an end point of the second frame and an end point of the first time resource. In general, the second frame sent by the first device in the UL scenario is a BA frame returned by the first device to the second device based on a SU PPDU received from the second device. Furthermore, in the UL scenario, the second device receives the BA frame sent by the first device and determines whether to continue using the first time resource based on a value relationship between a preset duration T and a duration between an end point of the second frame and an end point of the first time resource.

[0291] S302: The first device regains a permission to use the transmission opportunity TXOP when the duration between the end of the second frame and the end of the first time resource is shorter than a preset duration T.

[0292] In some possible implementations, the first device regains the permission to use the transmission opportunity TXOP if the duration between the end of the second frame and the end of the first time resource is shorter than the preset duration T. The first time resource is allocated to the second device from the obtained TXOP by the first device. Conversely, if the second device determines that the duration between the end of the second frame and the end of the first time resource is shorter than the preset duration T, the second device assumes by default that the first device regains the use of the TXOP. That is, the second device is no longer allowed to transmit SU PPDUs in the remaining duration of the SU SP.

[0293] Optionally, in some possible implementations, when the second device determines that the duration between the end of the second frame and the end of the first time resource is greater than T, in order to prevent waste, the second device can send a first frame to the first device to indicate that the second device has stopped using the first time resource. Correspondingly, the first device receives the first frame from the second device, and parses the first frame, so that the first device can recover the permission to use TXOP based on the first frame. In this embodiment of the present application, for the solution in which the second device sends the first frame to indicate that the second device has stopped using the first time resource, please refer to the process described in embodiment 1. Details will not be described here.

[0294] For the sake of clarity, FIG. 19 shows a schematic diagram of a scenario of recovering permission to use TXOP based on a preset duration T in a UL scenario according to the present application. As shown in FIG. 19, in a UL scenario, for the process from when a first device (e.g., AP in FIG. 19) transmits an mMU-RTS frame to when a second device (e.g., STA1 in FIG. 19) transmits a SU PPDU to a SU PPDU receiver (e.g., AP in FIG. 19) in a first resource (e.g., SU SP in FIG. 19), please refer to the process described in FIG. 2a. Details will not be described again here. When the AP transmits one BA frame to STA1 at any time in the first time resource, if the AP determines that the duration between the end of the BA frame and the end of the SU SP (e.g., T' in FIG. 19) is shorter than the preset duration T, the AP can recover the permission to use TXOP immediately after a SIFS. Conversely, if T' is greater than T, the AP does not recover the permission to use TXOP. Correspondingly, if STA1 receives a BA frame at any time in the first time resource and determines that the duration T' between the end of the BA frame and the end of the SU SP is less than T, STA1 will assume by default that the AP has restored permission to use the TXOP, i.e., STA1 is no longer allowed to transmit SU PPDUs for the remaining duration of the SU SP. Conversely, if STA1 determines that the duration T' is greater than T, the STA may continue to use the SU SP.

[0295] In this embodiment of the present application, in a UL scenario, the first device can transmit a second frame, and determine whether to restore / revoke the permission to use TXOP of the first device based on the value relationship between a time threshold (i.e., a preset duration T in this application) and a duration T' between the end of the second frame and the end of the first time resource. According to the solution in this embodiment of the present application, if T' is less than T, the permission to use TXOP is restored, and the permission to use TXOP can also be restored in advance. This can improve the utilization rate of channel resources and the reliability of restoring the permission to use TXOP.

[0296] Furthermore, in another embodiment of the present application, when an AP needs to revoke the permission to use TXOP for some reason (e.g., an emergency service arrives that should be transmitted immediately), the AP can actively recover / revoke the permission of the AP to use TXOP by sending an active recovery frame (i.e., the third frame in the present application). The following uses an example in which this embodiment is applied to a UL scenario for description. It can be understood that this embodiment can also be applied to other scenarios, which is not limited in the present application.

[0297] Specifically, Figure 20 is another schematic flowchart of a method for recovering permission to use a transmission opportunity according to an embodiment of the present application. As shown in Figure 20, the method for recovering permission to use a transmission opportunity includes the following steps:

[0298] S401: The first device determines a third frame.

[0299] In some possible implementations, if the AP needs to revoke permission to use the TXOP for some reason (e.g., when an emergency service arrives that should be transmitted immediately), the AP can send a third frame to indicate to the second device that the first device immediately revokes or will revoke permission to use the TXOP, so that after receiving the third frame, the second device no longer transmits SU PPDUs in the remaining duration of the first time resource.

[0300] The third frame may be an enhanced BA frame. That is, in the present application, the frame structure of the BA frame fed back by the first device to the second device may be modified. Thereby, the enhanced BA frame may indicate that the BA frame is a response frame of the first device based on the SU PPDU received from the second device, and may indicate that the first device actively recovers the permission to use the TXOP. In the present application, it may be understood that the BA Control field may be modified, so that the BA Control field may indicate that the first device actively recovers the permission to use the TXOP. Specifically, at least one bit included in a reserved field in the BA Control field may be set as a TXOP Recovery Indication field. For example, if the 1 bit included in the reserved field in the BA control field is set as a TXOP recovery indication field, it may be specified that when the TXOP recovery indication field is set to 1, it indicates that the first device immediately recovers the permission to use TXOP; when the field is set to 0, it indicates that the first device does not recover the permission to use TXOP. Alternatively, when the TXOP recovery indication field is set to 0, it indicates that the first device immediately recovers the permission to use TXOP; when the field is set to 1, it indicates that the first device does not recover the permission to use TXOP. This is not limited here.

[0301] For clarity, FIG. 21 illustrates a schematic diagram of the structure of an enhanced BA frame according to an embodiment of the present application. As shown in FIG. 21, the BA frame may include a Frame Control field, a Duration field, a Receiver Address (RA) field, a Sender Address (TA) field, a BA Control field, a BA Information field, a Frame Check Sequence (FCS) field, etc. The existing standard protocol (i.e., 802.11ax) specifies that the BA control field may include 16 bits. The first bit indicates a Block Ack Policy field, the second to fifth bits indicate a Block Type field, the sixth to twelfth bits indicate a Reserved field, and the thirteenth to sixteenth bits indicate a Service Identifier Information (TID_INFO) field. To enhance the BA control field, at least one bit in the sixth to twelfth bits in the BA control field may indicate a TXOP recovery indication field. For example, if the 1 bit included in the reserved field in the BA control field indicates the TXOP recovery indication field, any 1 bit from the 6th bit to the 12th bit can be set as the TXOP recovery indication field. For example, the 6th bit in the BA control field in FIG. 21 is set as the TXOP recovery indication field.

[0302] Furthermore, Figure 22 shows a schematic diagram of an application scenario in which a first device actively recovers permission to use TXOP according to the present application. As shown in Figure 22, in a UL scenario, the process from when a first device (e.g., AP in Figure 22) sends an mMU-RTS frame to when a second device (e.g., STA1 in Figure 22) sends a SU PPDU to a SU PPDU recipient (e.g., AP in Figure 22) in a first time resource (e.g., SU SP in Figure 22) can be referred to the process described in Figure 2a. Details are not described again here. If the AP needs to actively recover / revoke permission to use TXOP, the AP can use any BA frame to indicate to STA1 that the AP is going to revoke permission to use TXOP. As shown in FIG. 22, the AP transmits one enhanced BA frame (i.e., the third frame in this application) to STA1, and when SIFS has elapsed after transmitting the enhanced BA frame, it regains permission to use the TXOP (e.g., the AP transmits the PPDU in FIG. 22).

[0303] Optionally, the frame structure of the BA frame may not be modified / improved, and another frame (i.e., the fourth frame in this application) is aggregated with the BA frame. The other frame indicates that the first device actively recovers the permission to use the TXOP. That is, the third frame is an aggregated frame, and the aggregated frame is obtained by aggregating the BA frame with another frame (i.e., the fourth frame). It should be understood that in this application, all fourth frames with such a function are allowed to be aggregated. For example, the A-control field in the fourth frame includes the third indication information. The third indication information indicates that the first device actively recovers the permission to use the transmission opportunity TXOP. Specifically, the fourth frame may be a QoS data frame or a QoS null data frame, and the A-control field of the fourth frame carries a new type of A-control field (e.g., the control identifier value is 7). Please refer to FIG. 7 for the frame structure of the fourth frame. Details will not be described again here. Optionally, the frame type field in the third frame indicates that the third frame is a control frame, and the frame subtype field in the third frame indicates that the third frame is an active recovery frame. The active recovery frame indicates that the first device actively recovers permission to use a transmission opportunity TXOP. That is, another new control frame (e.g., the frame type field is binary 01 and the frame subtype field is binary 1111) may be further designed to indicate that the first device actively recovers permission to use a transmission opportunity TXOP. For ease of explanation, the new control frame may be referred to as an active recovery frame. Please refer to FIG. 8 for the frame structure of the active recovery frame. Details will not be described again here.

[0304] For the sake of clarity, Figure 23 shows another schematic diagram of the application scenario in which the first device actively recovers the permission to use TXOP according to the present application. As shown in Figure 23, in the UL scenario, the process from the time when the first device (e.g., AP in Figure 23) transmits an mMU-RTS frame to the time when the second device (e.g., STA1 in Figure 23) transmits a SU PPDU to the SU PPDU receiver (e.g., AP in Figure 23) in the first time resource (e.g., SU SP in Figure 23), please refer to the process described in Figure 2a. Details will not be described again here. If the AP needs to actively recover / revoke the permission to use TXOP, the AP may aggregate any BA frame with another frame (i.e., the fourth frame in the present application). The aggregated another frame indicates to STA1 that the AP recovers the permission to use TXOP. As shown in Figure 23, after aggregating the BA frame and another frame into a third frame, the AP sends the third frame to STA1, indicating to STA1 that the AP regains permission to use the TXOP. The AP may revoke permission to use the TXOP (e.g., the AP sends the PPDU in Figure 23) when SIFS has elapsed after sending the third frame.

[0305] S402: The first device transmits a third frame to the second device.

[0306] In some possible implementations, after determining the third frame, the first device may transmit the third frame to the second device. It may be understood that the first device may withdraw the permission to use the TXOP when SIFS has elapsed after transmitting the third frame. Alternatively, after transmitting the third frame, the first device may wait for the second device to retransmit the data frame k times and then withdraw the permission to use the TXOP. That is, the first device may withdraw the permission to use the TXOP when a pre-configured duration T0 has elapsed after transmitting the third frame. This is a buffer time provided by the first device to the second device, or sufficient time is reserved for another preparation. For ease of explanation, "The first device may withdraw permission to use the TXOP when a SIFS has elapsed after transmitting the third frame" may be shortened to "The first device immediately withdraws permission to use the TXOP", and "After transmitting the third frame, the first device may wait for the second device to retransmit the data frame k times and then withdraw permission to use the TXOP" may be shortened to "The first device delays withdrawing permission to use the TXOP", where k is an integer greater than 0 (e.g., k=1).

[0307] It may be understood that when the second device receives the third frame from the first device, the second device does not transmit the data frame anymore (i.e., when the first device immediately revokes the permission to use the TXOP, the second device is not allowed to retransmit the data frame at all). Alternatively, the second device is allowed to retransmit the data frame k times (i.e., the first device may delay revoking the permission to use the TXOP, and the second device may be allowed to retransmit the data frame k more times). The third frame may be an enhanced BA frame or an aggregated frame.

[0308] For clarity, please refer to Figure 22 or Figure 23. If the AP needs to actively recover / revoke permission to use the TXOP immediately, the AP may use any BA frame to indicate to STA1 that the AP will immediately revoke permission to use the TXOP. That is, the AP sends one improved BA frame to STA1, and when SIFS has elapsed after sending the BA frame, it recovers permission to use the TXOP (e.g., the AP sends the PPDU in Figure 22).

[0309] For the sake of clarity, Figure 24 shows another schematic diagram of the application scenario in which the first device actively recovers the permission to use TXOP according to the present application. As shown in Figure 24, in the UL scenario, the process from the time when the first device (e.g., AP in Figure 24) transmits an mMU-RTS frame to the time when the second device (e.g., STA1 in Figure 24) transmits a SU PPDU to the SU PPDU receiver (e.g., AP in Figure 24) in the first time resource (e.g., SU SP in Figure 24) can be referred to the process described in Figure 2a. Details will not be described again here. When the AP needs to actively revoke the permission to use TXOP, the AP may transmit an improved BA frame to STA1 to indicate to STA1 that the AP revokes the permission to use TXOP. In the scenario shown in Figure 24, the AP may allow STA1 to retransmit the SU PPDU once (i.e., k=1) after STA1 receives the improved BA frame. Therefore, after the AP transmits the enhanced BA frame to STA1, the AP may formally revoke / recover the permission to use the TXOP when the duration T0 has elapsed after completing the transmission of the BA frame (e.g., the AP transmits the PPDU in FIG. 24), where T0=3SIFS+SU PPDU+BA.

[0310] In this embodiment of the present application, if an AP needs to revoke permission to use a TXOP for some reason (e.g., an emergency service arrives that should be transmitted immediately), the AP can actively restore / revoke the AP's permission to use a TXOP by sending an active restoration frame (i.e., the third frame in this application). Such an active revocation aspect allows the AP to restore the permission to use a TXOP when necessary.

[0311] The relevant features between the above method embodiments may be combined, which is not limited hereto in this application.

[0312] The above contents describe in detail the method provided in the present application. In order to implement the above-mentioned solutions in the embodiments of the present application, the embodiments of the present application further provide a corresponding apparatus or device.

[0313] In the embodiment of the present application, based on the above method example, the first device and the second device may be divided into functional modules. For example, the functional modules may be obtained through division based on corresponding functions, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware, or in the form of a software functional module. It should be noted that in this embodiment of the present application, the module division is exemplary and is merely a logical functional division. In actual implementation, other division aspects may be used. The following describes in detail an apparatus for recovering permission to use a transmission opportunity according to an embodiment of the present application with reference to FIG. 25 and FIG. 26.

[0314] When an integrated unit is used, Fig. 25 is a schematic diagram of the structure of an apparatus 1 for recovering permission to use a transmission opportunity according to an embodiment of the present application. The apparatus for recovering permission to use a transmission opportunity may be a first device or a chip in the first device, such as a Wi-Fi chip. As shown in Fig. 25, the apparatus for recovering permission to use a transmission opportunity includes a processing unit 11 and a transceiver unit 12.

[0315] In one design, the transceiver unit 12 is configured to receive a first frame from a second device. The first frame indicates that the second device has stopped using a first time resource. The first time resource is allocated by the first device to the second device from an acquired transmission opportunity TXOP. The first time resource is allocated by the first device to the second device by using a single-user trigger frame. The processing unit 11 is configured to recover permission to use the TXOP based on the first frame.

[0316] Optionally, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0317] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0318] Optionally, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0319] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0320] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0321] Optionally, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of bits 4 to 8 in the CAS control field.

[0322] Optionally, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0323] In another design, the transceiver unit 12 is configured to receive a second frame. The processing unit 12 is configured to: recover a permission to use a transmission opportunity TXOP if a duration between an end time of the second frame and an end time of the first time resource is shorter than a preset duration T; a destination address of the second frame is an address of the second device; or alternatively, a sender address of the second frame is an address of the second device, and the second frame is a frame that does not request a response frame; and the first time resource is allocated by the first device to the second device from the obtained TXOP.

[0324] Optionally, the transceiver unit 12 is further configured to: receive a first frame from the second device if a duration between an end of the second frame and an end of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0325] Optionally, the first time resource is used for transmitting an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0326] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0327] Optionally, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0328] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0329] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0330] Optionally, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of bits 4 to 8 in the CAS control field.

[0331] Optionally, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0332] In another design, the transceiver / unit 12 is configured to transmit a second frame, where a destination address of the second frame is an address of the second device. The processing unit 11 is configured to: determine to recover a permission to use a transmission opportunity TXOP if the duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T. The first time resource is allocated by the first device to the second device from the obtained TXOP.

[0333] Optionally, the processing unit 11 is further configured to: receive a first frame from the second device when a duration between an end time of the second frame and an end time of the first time resource is greater than T. The first frame indicates that the second device has stopped using the first time resource.

[0334] Optionally, the first time resource is used for transmitting an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0335] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0336] Optionally, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0337] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0338] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0339] Optionally, the control identifier of the A-control field is a second value, which indicates that the A-control field is a command and status CAS control field.

[0340] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0341] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0342] Optionally, the frame type field in the first frame indicates that the first frame is a control frame and the frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource.

[0343] In another design, the processing unit 11 is configured to determine a third frame, and the transceiver unit is configured to transmit the third frame to the second device, the third frame indicating that the first device actively regains permission to use a transmission opportunity TXOP.

[0344] Optionally, the third frame is a block acknowledgement BA frame returned by the first device based on the data frame received from the second device, wherein the BA control field in the BA frame indicates that the first device actively regains permission to use the TXOP.

[0345] Optionally, the third frame is an aggregated frame, the aggregated frame being obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, the BA frame being generated by the first device based on a data frame received from the second device.

[0346] Optionally, the A-control field in the fourth frame includes a third indication, the third indication indicating that the first device actively recovers permission to use the TXOP.

[0347] Optionally, the control identifier of the A-control field is a third value, which indicates that the A-control field includes third indication information.

[0348] Optionally, a frame type field in the third frame indicates that the third frame is a control frame and a frame subtype field in the third frame indicates that the third frame is an active recovery frame, the active recovery frame indicating that the first device is actively recovering permission to use a transmission opportunity TXOP.

[0349] The device 1 for recovering permission to use a transmission opportunity may correspondingly perform steps in the above method embodiment, and it should be understood that the above operations or functions of the units in the device 1 for recovering permission to use a transmission opportunity are separately used to implement the corresponding operations performed by the first device in the above method embodiment. For corresponding beneficial effects, please refer to the method embodiment. For the sake of brevity, details will not be described again here.

[0350] See Figure 25. The device for recovering permission to use a transmission opportunity may alternatively be a second device or a chip in the second device, such as a Wi-Fi chip. As shown in Figure 25, the device for recovering permission to use a transmission opportunity includes a processing unit 11 and a transceiver unit 12.

[0351] In one design, the processing unit 11 is configured to determine a first frame indicating that the second device has stopped using a first time resource. The first time resource is allocated by the first device to the second device from an obtained transmission opportunity TXOP. The first time resource is allocated by the first device to the second device by using a single-user trigger frame.

[0352] Optionally, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0353] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0354] Optionally, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0355] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0356] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0357] Optionally, the control identifier of the A-control field is a second value. The second value indicates that the A-control field is a command and status CAS control field. The first indication is carried in a reverse acknowledgement RDG subfield in the CAS control field. Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of bits 4 to 8 in the CAS control field.

[0358] Optionally, a frame type field in the first frame indicates that the first frame is a control frame and a frame subtype field in the first frame indicates that the first frame is a time resource return frame, the time resource return frame indicating that the second device has stopped using the first time resource.

[0359] Optionally, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device transmits the first frame to the first device if an end time of the first frame is later than an end time of the first time resource and a start time of the first frame is earlier than an end time of the first time resource.

[0360] In another design, the transceiver unit 12 is configured to receive or transmit a second frame, the second frame being a frame that does not require a response frame, and if the duration between an end of the second frame and an end of the first time resource is shorter than the preset duration T, the second device does not transmit any more PPDUs.

[0361] Optionally, the second device further includes a processing unit 11. The processing unit 11 is configured to: transmit a first frame to the first device using the transceiver unit 12 if a duration between an end time of the second frame and an end time of the first time resource is greater than a preset duration T. The first frame indicates that the second device has stopped using the first time resource. The first time resource is allocated by the first device to the second device from the obtained TXOP.

[0362] Optionally, the first time resource is used for transmitting an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0363] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0364] Optionally, the first frame further carries second indication information, the second indication information indicating whether the second device further requires time resources for data transmission.

[0365] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0366] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0367] Optionally, the control identifier of the A-control field is a second value, which indicates that the A-control field is a command and status CAS control field.

[0368] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0369] Alternatively, the first indication is carried in an RDG subfield in the CAS control field and the second indication is carried in at least one of the fourth to eighth bits in the CAS control field.

[0370] Optionally, the frame type field in the first frame indicates that the first frame is a control frame and the frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource.

[0371] Optionally, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0372] In another design, the transceiver unit 12 is configured to receive a second frame from the first device, and the processing unit 11 is configured to: determine that the second device will not transmit any more PPDUs if a duration between an end of the second frame and an end of the first time resource is shorter than a preset duration T.

[0373] Optionally, the processing unit 11 is further configured to: determine to transmit a first frame to the first device using the transceiver unit 12 if the duration between an end time of the second frame and an end time of the first time resource is longer than a preset duration T. The first frame indicates that the second device has stopped using the first time resource. The first time resource is allocated by the first device to the second device from the obtained TXOP.

[0374] Optionally, the first time resource is used for transmission of an uplink single-user physical layer protocol data unit (PPDU) or for point-to-point P2P communication. The single-user trigger frame includes a first field and a second field. The first field indicates a remaining time resource of a TXOP, and the second field indicates the first time resource.

[0375] Optionally, the first frame carries a first indication, the first indication indicating that the second device has stopped using the first time resource.

[0376] Optionally, the first frame further carries second indication information, which indicates whether the second device further requires time resources for data transmission.

[0377] Optionally, the A control field in the first frame includes the first indication. Alternatively, the A control field in the first frame includes the first indication and the second indication.

[0378] Optionally, the control identifier of the A-control field is a first value, the first value indicating that the A-control field includes first indication information.

[0379] Optionally, the control identifier of the A-control field is a second value, which indicates that the A-control field is a command and status CAS control field.

[0380] The first indication information is carried in a reverse acknowledgement RDG subfield in the CAS control field.

[0381] Alternatively, the first indication is carried in an RDG subfield in the CAS control field, and the second indication is carried in at least one bit among the fourth to eighth bits in the CAS control field.

[0382] Optionally, the frame type field in the first frame indicates that the first frame is a control frame and the frame subtype field in the first frame indicates that the first frame is a time resource return frame. The time resource return frame indicates that the second device has stopped using the first time resource.

[0383] Optionally, if the first frame is a quality of service QoS null data frame or if the first frame is a time resource return frame, the second device is allowed to transmit the first frame to the first device if the end time of the first frame is later than the end time of the first time resource and the start time of the first frame is earlier than the end time of the first time resource.

[0384] In another design, processing unit 11 is configured to: determine that the second device does not transmit the data frame via transceiver unit 12, and retransmit the data frame via transceiver unit 12 k times when the second device receives a third frame from the first device, the third frame indicating that the first device actively regains permission to use a transmission opportunity TXOP, where k is an integer greater than 0.

[0385] Optionally, the third frame is a block acknowledgement BA frame returned by the first device based on the data frame received from the second device, wherein the BA control field in the BA frame indicates that the first device actively regains permission to use the TXOP.

[0386] Optionally, the third frame is an aggregate frame, the aggregate frame being obtained by aggregating a fourth frame with a BA frame, the fourth frame indicating that the first device actively recovers permission to use the TXOP, the BA frame being generated by the first device based on a data frame received from the second device.

[0387] Optionally, the A-control field in the fourth frame includes a third indication, the third indication indicating that the first device actively recovers permission to use the TXOP.

[0388] Optionally, the control identifier of the A-control field is a third value, which indicates that the A-control field includes third indication information.

[0389] Optionally, a frame type field in the third frame indicates that the third frame is a control frame and a frame subtype field in the third frame indicates that the third frame is an active recovery frame, the active recovery frame indicating that the first device is actively recovering permission to use a transmission opportunity TXOP.

[0390] The device 1 for recovering permission to use a transmission opportunity may further correspondingly perform steps in the above method embodiment, and it should be understood that the above operations or functions of the units in the device 1 for recovering permission to use a transmission opportunity are separately used to implement the corresponding operations performed by the second device in the above method embodiment. For corresponding beneficial effects, please refer to the method embodiment. For the sake of brevity, details will not be described again here.

[0391] The above describes the first device and the second device in the embodiment of the present application. The following describes possible product forms of the first device and the second device. It should be understood that any form of a product having the function of the first device in FIG. 25, or any form of a product having the function of the second device in FIG. 25, or both, falls within the scope of protection of the embodiment of the present application. It should be further understood that the following description is merely an example, and the product forms of the first device and the second device in the embodiment of the present application are not limited thereto.

[0392] In one possible product form, the first device and the second device in the embodiments of the present application may be implemented using a common bus architecture.

[0393] For ease of explanation, Fig. 26 shows a schematic diagram of the structure of a communication device 1000 according to an embodiment of the present application. The communication device 1000 may be a first device, a second device, or a chip in the first device or the second device. Fig. 26 shows only the main components of the communication device 1000. In addition to the processor 1001 and the transceiver 1002, the communication device may further include a memory 1003 and an input / output device (not shown).

[0394] The processor 1001 is mainly configured to process communication protocols and communication data, control communication devices, execute software programs, and process data of the software programs. The memory 1003 is mainly configured to store software programs and data. The transceiver 1002 may include a control circuit and an antenna. The control circuit is mainly configured to convert between baseband signals and radio frequency signals, and process the radio frequency signals. The antenna is mainly configured to transmit and receive radio frequency signals in the form of electromagnetic waves. The input / output devices, such as a touch screen, a display, and a keyboard, are mainly configured to receive data input by a user and output data to a user.

[0395] After the communication device is powered on, the processor 1001 can read the software program in the memory 1003, interpret and execute the instructions of the software program, and process data of the software program. When data needs to be transmitted wirelessly, the processor 1001 performs baseband processing on the data to be transmitted, and then outputs the baseband signal to the radio frequency circuit. After performing radio frequency processing on the baseband signal, the radio frequency circuit transmits the radio frequency signal in the form of electromagnetic waves through an antenna. When data is transmitted to the communication device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor 1001. The processor 1001 converts the baseband signal into data and processes the data.

[0396] In another implementation, the radio frequency circuitry and antenna may be located independently of the processor performing the baseband processing, for example in a distributed scenario, where the radio frequency circuitry and antenna may be located independently of the communication device.

[0397] The processor 1001, the transceiver 1002, and the memory 1003 may be connected via a communication bus.

[0398] In one design, the communications apparatus 1000 may be configured to perform functions of the first device in the method embodiments described above. The processor 1001 may be configured to perform step S102 of FIG. 3, and / or step S202 of FIG. 16, and / or step S302 of FIG. 18, and / or step S401 of FIG. 20, and / or other processes of the techniques described herein. The transceiver 1002 may be configured to perform step S101 of FIG. 3, and / or step S201 of FIG. 16, and / or step S301 of FIG. 18, and / or step S402 of FIG. 20, and / or other processes of the techniques described herein.

[0399] In another design, the communication apparatus 1000 may be configured to perform functions of the second device in the embodiments of the method described above. The processor 1001 may be configured to determine the first frame in step S101 of FIG. 3, and / or step S202 of FIG. 16, and / or step S302 of FIG. 18, and / or step S402 of FIG. 20, and / or another process of the techniques described herein. The transceiver 1002 may be configured to transmit the first frame in step S101 of FIG. 3, and / or step S201 of FIG. 16, and / or step S301 of FIG. 18, and / or step S401 of FIG. 20, and / or another process of the techniques described herein.

[0400] In any of the above designs, the processor 1001 may include a transceiver configured to implement receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, the interface, or the interface circuit configured to implement the transmitting and receiving functions may be separate or integrated together. The transceiver circuit, the interface, or the interface circuit may be configured to read and write code / data. Alternatively, the transceiver circuit, the interface, or the interface circuit may be configured to transmit or forward signals.

[0401] In any of the above designs, the processor 1001 may store instructions. The instructions may be a computer program. The computer program may execute on the processor 1001 to enable the communication device 1000 to perform the method described in any of the method embodiments above. The computer program may be fixed in the processor 1001, in which case the processor 1001 may be implemented by hardware.

[0402] In some implementations, the communication device 1000 may include circuitry that may implement the transmitting, receiving, or communication functions of the method embodiments described above. The processors and transceivers described herein may be implemented in integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed signal ICs, application specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processors and transceivers may alternatively be fabricated using various IC technologies, such as complementary metal oxide semiconductor (CMOS), nMetal-oxide-semiconductor (NMOS), positive channel metal oxide semiconductor (PMOS), bipolar junction transistor (BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), and gallium arsenide (GaAs).

[0403] The scope of the communication device described herein is not limited in this respect, and the structure of the communication device may not be limited by FIG. 26. The communication device may be a separate device or may be part of a larger device. For example, a communication device may include: (1) An independent integrated circuit IC, chip, or chip system or subsystem; (2) a set including one or more ICs (optionally, the set of ICs may further include a storage component configured to store data and computer programs); (3) ASIC, e.g., modem; (4) A module that can be incorporated into other devices; (5) Receivers, terminals, intelligent terminals, mobile phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.; or (6) Another device, etc.

[0404] In one possible product form, the first device and the second device in the embodiments of the present application may be implemented by a general-purpose processor.

[0405] A general-purpose processor implementing the first device includes a processing circuit and an input / output interface interconnected to and communicating with the processing circuit.

[0406] In one design, the general-purpose processor may be configured to perform the functions of the first device in the method embodiments described above. Specifically, the processing circuitry is configured to perform step S102 of FIG. 3, and / or step S202 of FIG. 16, and / or step S302 of FIG. 18, and / or step S401 of FIG. 20, and / or another process of the techniques described herein. The input / output interface is configured to perform step S101 of FIG. 3, and / or step S201 of FIG. 16, and / or step S301 of FIG. 18, and / or step S402 of FIG. 20, and / or another process of the techniques described herein.

[0407] A general-purpose processor for implementing the second device includes a processing circuit and an input / output interface interconnected to and in communication with the processing circuit.

[0408] In one design, the general-purpose processor may be configured to perform the functions of the second device in the embodiments of the method described above. Specifically, the processing circuit is configured to determine a first frame in step S101 of FIG. 3, and / or step S202 of FIG. 16, and / or step S302 of FIG. 18, and / or step S40 of FIG. 20, and / or another process of the techniques described herein. The input / output interface is configured to transmit a first frame in step S101 of FIG. 3, and / or step S201 of FIG. 16, and / or step S301 of FIG. 18, and / or step S402 of FIG. 20, and / or another process of the techniques described herein.

[0409] It should be understood that the communication device in the above various product forms can have the functions of either the first device or the second device in the above method embodiments, and can correspondingly perform the steps in the above method embodiments to achieve corresponding technical effects. For the sake of brevity, details will not be described again here.

[0410] An embodiment of the present application further provides a computer-readable storage medium, which stores computer program code, which, when executed by a processor, causes an electronic device to perform the method of any of the above embodiments.

[0411] An embodiment of the present application further provides a computer program product, which when executed on a computer, enables the computer to perform the method of any of the above-described embodiments.

[0412] An embodiment of the present application further provides a communication device, which may exist in the form of a chip product. The structure of the device includes a processor and an interface circuit. The processor is configured to communicate with other devices through the interface circuit, so that the device can perform any of the methods in the above embodiments.

[0413] An embodiment of the present application further provides a wireless communication system including a first device and a second device, the first device and the second device being capable of performing the method of any of the above embodiments.

[0414] The method or algorithm steps described in conjunction with the disclosure herein may be implemented using hardware or may be implemented using a processor executing software instructions. The software instructions may include corresponding software modules. The software modules may be stored in a Random Access Memory (RAM), a flash memory, an Erasable Programmable Read Only Memory (EPROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a register, a hard disk, a removable hard disk, a Compact Disk Read Only Memory (CD-ROM), or other forms of storage medium well known in the art. For example, the storage medium may be coupled to the processor, and the processor may read information from or write information to the storage medium. Of course, the storage medium may be components of the processor. The processor and the storage medium may be located in an ASIC. Furthermore, the ASIC may be located in a core network interface device. Of course, the processor and the storage medium may reside in the core network interface device as discrete components.

[0415] Those skilled in the art will recognize that the functions described herein in one or more of the above examples may be implemented using hardware, software, firmware, or any combination thereof. If the functions are implemented by software, they may be stored on or transmitted as one or more instructions or codes in a computer-readable medium. Computer-readable media includes computer-readable storage media and communication media. Communication media includes media that facilitate the transfer of a computer program from one place to another. Storage media may be any available media accessible to a general-purpose or special-purpose computer.

[0416] In the above specific implementation, the objectives, technical solutions and beneficial effects of the present application are further described in detail. It should be understood that the above description is only a specific implementation of the present application, but is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made based on the technical solutions of the present application should fall within the protection scope of the present application.

Claims

1. 13. A method of recovering permission to use a transmission opportunity, comprising: receiving, by a second device, a trigger frame from a first device, the trigger frame indicating that a time resource is to be allocated to the second device from a transmit opportunity (TXOP) obtained by the first device; determining, by the second device, a Quality of Service (QoS) data frame, the QoS data frame including an A-control field, the A-control field including a control identifier indicating that the A-control field is a Command and Status (CAS) control field, and a Reverse Acknowledge (RDG) / Further PPDU subfield indicating that the second device has stopped using the time resource; transmitting, by the second device, the QoS data frame to the first device; method.

2. 2. The method of claim 1, wherein the time resource is used for transmission of an uplink physical layer protocol data unit (PPDU) or is used for point-to-point (P2P) communication, and the trigger frame includes a first field and a second field, the first field indicating a remaining time resource of the TXOP, and the second field indicating the time resource allocated to the second device.

3. 2. The method of claim 1, wherein the second device is allowed to transmit the QoS data frame to the first device if the end time of the QoS data frame is later than the end time of the time resource and the start time of the QoS data frame is earlier than the end time of the time resource.

4. 1. An apparatus for recovering permission to use a transmission opportunity, the apparatus being a second device, the apparatus comprising: a transceiver unit configured to receive a trigger frame from a first device, the trigger frame indicating that a time resource is to be allocated to the second device from a transmission opportunity (TXOP) obtained by the first device; a processing unit configured to determine a Quality of Service (QoS) data frame, the QoS data frame including an A-control field, the A-control field including a control identifier indicating that the A-control field is a Command and Status (CAS) control field, and a Reverse Acknowledge (RDG) / Further PPDU subfield indicating that the second device has stopped using the time resource; the transceiver unit is further configured to transmit the QoS data frame to the first device. Device.

5. A communications device having a processor and a memory, the memory configured to store computer instructions; The processor executes the computer instructions stored in the memory to enable the device to perform the method of any one of claims 1 to 3. Communications equipment.

6. A computer readable storage medium having stored thereon program instructions which, when executed on a computer, enable the computer to carry out the method of any one of claims 1 to 3.

7. A computer program product comprising program instructions which, when executed on a computer, enable the computer to carry out a method according to any one of claims 1 to 3.

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