Transmit opportunity preemtpion

Abstract

Embodiments of the present disclosure disclose devices, methods and apparatuses for the transmit opportunity (TXOP) preemption. In the embodiments, an apparatus 5 performs, based on one or more parame

Description

FIELD

[0001] Various example embodiments relate to the field of communications and in particular, to devices, methods, apparatuses and a computer readable medium for the transmit opportunity (TXOP) preemption. BACKGROUND

[0002] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0003] Such communication networks typically operate in accordance with standards, such as those promulgated by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of such standards include the so-called 5G (5th Generation) standard or other standards promulgated by 3GPP. SUMMARY

[0004] In general, example embodiments of the present disclosure provide a solution for the TXOP preemption, especially for TXOP preemption-related parameters.

[0005] In a first aspect, there is provided an apparatus. The apparatus comprises at least one processor at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: based on one or more parameters, an operation related to transmit opportunity (TXOP) preemption. The one or more parameters comprises at least one of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; or a fifth parameter indicating that the TXOP preemption is performed.

[0006] In a second aspect, there is provided a method implemented at an apparatus. The method comprises: performing, based on one or more parameters, an operation related to TXOP preemption. The one or more parameters comprises at least one of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; or a fifth parameter indicating that the TXOP preemption is performed.

[0007] In a third aspect, there is provided an apparatus comprising means for performing, based on one or more parameters, an operation related to TXOP preemption. The one or more parameters comprises at least one of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; or a fifth parameter indicating that the TXOP preemption is performed.

[0008] In a fourth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the second aspect.

[0009] In a fifth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: perform at least the method according to the second aspect.

[0010] In a sixth aspect, there is provided an apparatus. The apparatus comprises performing circuitry configured to perform, based on one or more parameters, an operation related to TXOP preemption. The one or more parameters comprises at least one of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; or a fifth parameter indicating that the TXOP preemption is performed.

[0011] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0013] FIG. 1A illustrates an example communication network in which embodiments of the present disclosure may be implemented;

[0014] FIG. IB illustrates an example of a transmit opportunity (TXOP);

[0015] FIG. IC illustrates a first example of a TXOP preemption;

[0016] FIG. ID illustrates a second example of a TXOP preemption;

[0017] FIG. IE illustrates a third example of a TXOP preemption;

[0018] FIG. IF illustrates a fourth example of a TXOP preemption;

[0019] FIG. 1G illustrates a fifth example of a TXOP preemption;

[0020] FIG. 2 illustrates a flowchart of a method implemented at an apparatus according to some embodiments of the present disclosure;

[0021] FIG. 3 illustrates an example of a TXOP preemption duration indicated by a first parameter according to some embodiments of the present disclosure;

[0022] FIG. 4 illustrates an example of a TXOP preemption timing indicated by a second parameter according to some embodiments of the present disclosure;

[0023] FIG. 5 illustrates an example of a number of stations allowed to perform the TXOP preemption indicated by a third parameter according to some embodiments of the present disclosure;

[0024] FIG. 6A illustrates an example of an allowed number of times of the TXOP preemption indicated by a fourth parameter according to some embodiments of the present disclosure;

[0025] FIG. 6B illustrates another example of an allowed number of times of the TXOP preemption indicated by a fourth parameter according to some embodiments of the present disclosure;

[0026] FIG. 7 illustrates an example of a notification about the TXOP preemption indicated by the fifth parameter according to some embodiments of the present disclosure;

[0027] FIG. 8 illustrates an example of the TXOP preemption indication of a sixth parameter that is variable in a TXOP according to some embodiments of the present disclosure;

[0028] FIG. 9 illustrates an example of a feedback indicated by the seventh parameter according to some embodiments of the present disclosure;

[0029] FIG. 10 illustrates an example of one or more times of the TXOP preemption using one or more parameters according to example embodiments of the present disclosure;

[0030] FIG. 11 illustrates another example of one or more times of the TXOP preemption using one or more parameters according to example embodiments of the present disclosure;

[0031] FIG. 12 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

[0032] FIG. 13 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

[0033] Throughout the drawings, the same or similar reference numerals represent the same or similar element. DETAILED DESCRIPTION

[0034] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

[0035] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0036] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0037] It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0039] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0040] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0041] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as 5GNew Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned systems.

[0042] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB, a base station of a 5G system), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0043] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0044] In some embodiments of the disclosure, the term “station (STA)” refers to a wireless communication apparatus configured to operate in a wireless network. For example, the STA may include, but not limited to, an access point (AP) station which provides the network coverage for the devices in the wireless network, and non-AP station in the wireless network.

[0045] In some wireless communication networks, for example, the Wi-Fi networks, a mechanism referred to as “transmit opportunity (TXOP)” is involved. TXOP is the STA’s (AP STA or non-AP STA) time duration, in which the STA can transmit frames (such as, medium access control, MAC, layer frame, physical, PHY, layer frame, and so on). When an STA obtains access to the channel (e.g., based on Enhanced Distributed Channel Access, EDCA), this STA becomes TXOP holder. During TXOP of this STA, no other STA is allowed to transmit any frame, except some essential frames, such as an acknowledge (ACK) frame transmitted from a TXOP responder. The TXOP responder refers to another STA that receives frames from the TXOP holder during TXOP. Moreover, the TXOP holder may be the AP STA or the non-AP STA in the wireless network. Correspondingly, the TXOP responder may be the non-AP STA or the AP STA without any limitation. A specific example of a TXOP is further discussed with reference to FIG. IB.

[0046] Since no other STA is allowed to transmit any frame during the TXOP of the TXOP holder, a communication delay at the other STA may occur. In turn, the so-called “TXOP preemption” is introduced to achieve low latency or reduce the latency. Specifically, the “TXOP preemption” refers to cutting or interrupting the on-going transmission within TXOP (i.e. on-going TXOP) to allow another STA (AP or non-AP STA) other than the TXOP holder to obtain TXOP and send their frames. In this way, the low latency (LL) frames can be transmitted timely, compared to the case that in normal circumstances, a STA (AP or non-AP STA) has to wait until another STA’s (AP or non-AP STA) TXOP is finished, then contend for the medium (based on the EDCA) to gain access to the channel and transmits that frame (if it wins the contention). As mentioned above, waiting for a STA’s (AP or non-AP STA) TXOP and trying to gain access to the channel may result in delay of the LL frame delivery. Thus, with TXOP preemption, the STA (AP or non-AP STA) does not have to wait until another STA’s TXOP, instead, the STA (AP or non-AP STA) may cut or interrupt the on-going TXOP to transmit the LL frame that arrives at the STA. As such, the latency of frame delivery can be low or reduced. Some examples of the TXOP preemption are further discussed with reference to FIGS. IC to 1G. Without any limitation, some embodiments of the disclosure are discussed with regard to, but not limited to, IEEE 802.11bn.

[0047] Regarding the TXOP preemption, some proposals have been submitted to the standard. Most of them focus on how to handle the interruption of the TXOP. For example, in some proposals, STA(AP or non-AP STA) is able to interrupt the ongoing TXOP no matter whether having the permission and / or a request is transmitted and accepted. Alternatively, in some proposals, STA (AP or non-AP STA) should ask permission to interrupt the ongoing TXOP, and perform the TXOP preemption upon obtaining the permission (i.e. TXOP preemption request / response - accepted or rejected). Alternatively, in some proposals, the cutting or interruptions take place in the small inter-frame space (IFS) Alternatively, in some proposals, different types of frames (for example, MAC layer frame, management frame of the MAC frame, control frame of the MAC frame, data frame of the MAC frame or PHY layer frame) are used for TXOP preemption request / response.

[0048] It can be seen that most of the proposals are mainly related to the criterion or rule for performing the TXOP preemption. Moreover, although these proposals discussed the example cases extensively and proposed detailed signaling (frames) on how to handle TXOP preemption, more specific aspects of TXOP preemption may be studied.

[0049] Without any limitation, some example issues that may be faced are listed below if only focusing on the criterion or rule for performing the TXOP preemption. It is to be understood that these issues are only shown as examples and there may be more issues to be faced which are not shown.

[0050] The duration of the TXOP preemption needs to be determined, i.e., how long the TXOP preemption should take place, E.g., one frame, 1 ms, 2 ms, or whole TXOP. If the TXOP preemption duration takes a long time, other STAs (not part of TXOP preemption) need to delay their transmissions.

[0051] In addition, the timing for performing the TXOP preemption needs to be determined, i.e., when the TXOP preemption should occur, for example, immediately after a LL frame arrives at STA. Whether the LL frame should wait for a period. If TXOP preemption timing is not appropriate, other STAs in the network may in the network may find themselves in an “unfair” situation.

[0052] In addition, the number of users (STAs) allowed to perform the TXOP preemption needs to be determined, i.e., how many STAs are allowed to perform TXOP preemption, for example, one STA, five 5 STAs, or more. If the number of STAs allowed to perform the TXOP preemption is relatively high, other STAs may be affected significantly. For example, the TXOP holder almost never has a chance to transmit.

[0053] In addition, the number of times of the TXOP preemption needs to be determined, i.e., how many times a STA or a group of STAs is allowed to perform the TXOP preemption, for example, one time, five times or more. Similarly, if the number of times is relatively more, other STAs may be affected significantly.

[0054] In addition, the indication of whether the TXOP preemption has not been designed, i.e., how to indicate TXOP preemption is allowed or not, in advance.

[0055] In addition, a notification that the TXOP preemption is performed already has not been designed, i.e., how to inform a STA that TXOP preemption took place, so that it understands that the TXOP is interrupted already.

[0056] In addition, a preemption feedback mechanism for the TXOP preemption can be further studied, for example, when some things go wrong need clarification in TXOP preemption, how to feedback the STA about the problem.

[0057] In addition, a priority level associated with the TXOP preemption may be determined, for example, which LL frames are allowed to perform the TXOP preemption. In addition or alternatively, there may be more potential issues to be faced if the specific aspects of TXOP preemption are not studied.

[0058] In view of these analyses and considerations, a new solution is proposed in some embodiments of the present disclosure. Specifically, some parameters (which may be also referred to as TXOP preemption, TXOP-P, parameters in some embodiments) shall be defined for the TXOP preemption such that the TXOP preemption may work properly and appropriately.

[0059] In some aspects, an apparatus performs, based on one or more parameters, an operation related to transmit opportunity (TXOP) preemption. The one or more parameters may include one or more of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; a fifth parameter indicating that the TXOP preemption is performed; a sixth parameter indicating whether the TXOP preemption is allowed; a seventh parameter indicating feedback for the TXOP preemption; or an eighth parameter indicating a priority level of a frame related to the TXOP preemption. In this way, by introducing these parameters, the TXOP preemption may be performed properly and appropriately during the TXOP. Furthermore, these parameters may be broadcast or unicast to the associated apparatuses in any way, for example, in the MAC layer frame or PHY layer frame. In addition or alternatively, these parameters may be pre-set, informed or changed. As such, the apparatuses in the wireless network may have a consistent understanding related to the TXOP preemption.

[0060] Principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is first made to FIG. 1 A, which illustrates an example communication system 100 (or referred to as communication network) in which embodiments of the present disclosure may be implemented. The system 100, for example, a communication network, includes a plurality of STAs. The plurality of STAs may include the AP STA110, non-AP STAs 120, 130, 140 and 150. Only as an example and without any limitation, the communication system 100 may be Wi-Fi wireless communication system. In some embodiments, the AP STA 110 may provide the network coverage for the non-AP STAs 120, 130, 140 and 150. It is to be understood that the communication system 100 may be any other wireless communication system. As mentioned above, any of the plurality of the STAs shown in FIG. 1A may be a TXOP holder, a TXOP responder, or an initiator of the TXOP preemption. Some examples of TXOP scenario and TXOP preemption scenarios are further discussed with reference to FIGS. 1A to 1G.

[0061] It is to be understood that the number of apparatuses is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of STAs adapted for implementing embodiments of the present disclosure.

[0062] Communications in the communication system 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0063] FIG. IB illustrates an example of a transmit opportunity (TXOP). In FIG. IB, the concept of TXOP is shown. In the example of FIG. IB, the TXOP holder is an AP station (for example, the AP station 110 in FIG. 1), and the TXOP responder is a non-AP STA (for example, the non-AP station 120, 130, 140 or 150). In an example, AP may gain access to the channel based on the EDC A to become the TXOP holder. In this case, AP transmits its frames to non-AP STA during its TXOP. Since the AP station is sending its frames to the non-AP STA, the non-AP STA becomes the TXOP responder. For example, if the AP 110 sends its frame to non-AP station 120, the non-AP station 120 becomes the TXOP responder. Alternatively, if the AP 110 sends its frame to non-AP station 130, the non-AP station 130 becomes the TXOP responder. As mentioned above, no other STA (e.g., the non-AP stations 140 and 150) can interrupt AP’s TXOP while it is sending its frames. Except for the TXOP responder (non-AP STA) can send some essential frames, such as acknowledge (ACK) message for a single data block, or a block ACK (BACK) message for multiple data blocks during AP’s TXOP. Some examples of the TXOP preemption are discussed with reference to FIGS. IC to 1G.

[0064] FIG. IC illustrates a first example of a TXOP preemption. As shown in FIG. IC, AP (e.g., AP station 110) is the TXOP holder, and non-AP STA1 (e.g., non-AP station 120) is TXOP responder (i e., receiving transmission from AP). Non-AP STA2 (e.g., non-AP station 130) is not the TXOP holder, because non-AP STA 2 is not a part of the transmission during the TXOP. While AP (TXOP holder) transmits its frames to non-AP STA1 (TXOP responder), LL frame may arrive at non-AP STA2 (non-TXOP holder). Non-AP STA2 may interrupt the AP’s TXOP (on-going TXOP) to send its LL frame, i.e., non-AP STA2 performs the TXOP preemption.

[0065] FIG. ID illustrates a second example of a TXOP preemption. As shown in FIG. ID, AP is the TXOP holder, and non-AP STA1 is the TXOP responder (i.e., receiving transmission from AP). Non-AP STA2 is not the TXOP holder, because non-AP STA 2 is not a part of the transmission. While AP (TXOP holder) transmits its frames to non-AP STA1 (TXOP responder), LL frame may arrive at non-AP STA1 (TXOP responder). In this case, non-AP STA1 may interrupt the AP’s TXOP (on-going TXOP) to send its LL frame, i.e., non-AP STA1 performs the TXOP preemption.

[0066] FIG. IE illustrates a third example of a TXOP preemption. As shown in FIG. IE, non-AP STA1 is the TXOP holder, and AP is the TXOP responder (i.e. receiving transmission from non-AP STA1). Non-AP STA2 is not the TXOP holder, because non-AP STA2 is not a part of the transmission. While non-AP STA1 (TXOP holder) transmits its frames to AP (TXOP responder), LL frame may arrive at non-AP STA2 (which is not the TXOP holder). Non-AP STA2 may interrupt the non-AP STAl’s TXOP (on-going TXOP) to send its LL frame, i.e., non-AP STA2 performs the TXOP preemption.

[0067] FIG. IF illustrates a fourth example of a TXOP preemption. As shown in FIG. IF, non-AP STA1 is TXOP holder, and AP is TXOP responder (i.e. receiving transmission from non-AP STA1). Non-AP STA2 is not the TXOP holder, because it is not a part of the transmission. While non-AP STA1 (TXOP holder) transmits its frames to AP (TXOP responder), LL frame may arrive at AP (TXOP responder) for non-AP STAl. AP may interrupt the non-AP STAl’s TXOP (on-going TXOP) to send its LL frame to non-AP STAl, i.e., AP performs the TXOP preemption.

[0068] FIG. 1G illustrates a fifth example of a TXOP preemption. As shown in FIG. 1G, non-AP STAl is TXOP holder, and AP is TXOP responder (i.e., receiving transmission from non-AP STAl). Non-AP STA2 is non-TXOP holder, because the non-TXOP holder is not a part of the transmission. While non-AP STAl (TXOP holder) transmits its frames to AP (TXOP responder), LL frame for the non-AP STA2 may arrive at AP (TXOP responder). AP may interrupt the non-AP STAl’s TXOP (on-going TXOP) to send its LL frame to non-AP STA2, i.e., AP performs the TXOP preemption.

[0069] Reference is now made to FIG. 2, which illustrates a flowchart 200 of a method implemented at an apparatus according to some embodiments of the present disclosure. Only for discussion simplicity, the embodiments are mainly discussed with reference to the communication system 100 as shown by FIG. 1A. It would be appreciated that although the signaling process 200 has been described in the communication environment 100 of FIG. 1 A, this flowchart 200 may be likewise applied to other communication scenarios.

[0070] As shown in FIG. 2, at 210 of the flowchart 200, an apparatus performs an operation related to TXOP preemption based on one or more parameters. This apparatus may be any one of the plurality stations shown in FIG. 1A. Without any limitation, this apparatus may be any other communication device in another communication system in which the communication devices obtain the channel occupancy based on the contention mechanism. That is, no matter whether it is the TXOP holder, TXOP responder or other STAs, the operation related to the TXOP preemption is performed based on the one or more parameters.

[0071] These one or more parameters may include a first parameter (which may be also referred to as TXOP-P duration parameter in some embodiments) indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption. For example, when a STA interrupts an on-going TXOP, the STA should know how long it should perform the TXOP preemption. The first parameter may indicate or define the minimum, maximum or suggested duration TXOP preemption should occupy or take place. In some embodiments, the first parameter may be also referred to as “TXOP-P duration parameter”. With the TXOP-P duration, the STA knows how long it should perform TXOP preemption.

[0072] In some embodiments, the suggested duration indicated by the first parameter may be an intermediate duration between the minimum duration and the maximum duration. In some embodiments, the suggested duration may be determined based on the communication requirement, for example, the duration required to transmit the LL frames, the remaining time of the TXOP, the load state of the wireless network and so on.

[0073] In some embodiments, the first parameter may indicate a number of time units of the TXOP preemption or a range of the duration of the TXOP preemption.

[0074] For example, the indicated duration may be an exact number, such as the number of allowed frames (e.g. 3 frames) or the time duration (such as 1 milliseconds or such as the number of time slots -e.g. units of 16ps). In addition, the duration may be the maximum, minimum, or suggested number of time units, such as the range of the allowed frames: maximum five (5) frames, minimum two (2) frames, and / or suggested three (3) frames. In another example, the duration may be a range of the time duration, such as, maximum 5ms or 5xl6ps, minimum 2 ms or 2xl6ps, and / or suggested 3 ms or 3xl6ps.

[0075] In some embodiments, if a STA is to perform the TXOP preemption, the STAs may request a TXOP duration by transmitting the first parameter in a TXOP preemption request. Then, the corresponding STA having the right to schedule the TXOP (e.g., the TXOP holder or AP) may accept, reject or modify the first parameter. Only as an example, assuming that the AP 110 is the TXOP holder, and the non-STA station 120 is to perform the TXOP preemption. The non-STA station 120 may transmit a TXOP preemption request including the first parameter to the AP station 110. The AP station 110 may accept the TXOP preemption duration indicated by the first parameter and inform the non-AP station 120 of the first parameter being accepted. In this case, the non-STA 120 may initiate the TXOP preemption having the duration indicated by the first parameter.

[0076] Alternatively, the AP station 110 may reject the first parameter. In this case, the non-AP station 120 may transmit another request or wait until the TXOP expiring. Alternatively, the AP station 110 may modify the duration indicated by the first parameter, and indicate the modified duration to the non-station 120. In this case, the non-AP station 120 may initiate the TXOP preemption with the modified duration. It is to be understood that the above embodiments are only example scenarios, the first parameter indicating the duration of the TXOP preemption may be applied to any other possible TXOP preemption scenarios. In addition or alternatively, the first parameter may indicate a periodicity of the TXOP preemption. That is, the first parameter indicates that the TXOP preemption may be performed periodically and indicate the required periodicity. Only as an example, the first parameter is further discussed with reference to FIG. 3.

[0077] FIG. 3 illustrates an example of a TXOP preemption duration indicated by the first parameter according to some embodiments of the present disclosure.

[0078] As shown in FIG. 3, the duration of the TXOP is 3ms, and the TXOP preemption duration 310 indicated by the first parameter is, for example, 1ms. In this case, the TXOP preemption may occur for 1ms.

[0079] Referring back to FIG. 2, in addition or alternatively, these one or more parameters may include a second parameter (which may be also referred to as TXOP-P timing parameter in some embodiments) indicating timing of the TXOP preemption. For example, when a STA intends to interrupt an on-going TXOP, the STA should know when exactly it should perform the TXOP preemption. In some embodiments, the second parameter may indicate that the TXOP preemption can be performed immediately after a frame that arrives at the STA ends or within a time period after the frame ends. As an example, assuming that a STA which is not the TXOP holder obtains the second parameter, and the second parameter indicates that the TXOP preemption can be performed immediately. In this case, the STA may perform the TXOP preemption immediately upon that the frame arriving at the STA ends.

[0080] In addition or alternatively, the second parameter may indicate that the TXOP preemption can be performed with a time delay after a frame arrives at a station. As an example, the second parameter may indicate that the timing is an exact number, such as the exact time (e.g. pre-emption is allowed exactly 3 ms later than the frame ending). As an example, assuming that a STA which is not the TXOP holder obtains the second parameter, and the second parameter indicates that the TXOP preemption can be performed after 3ms later than the frame arriving at the STA. In this case, the STA may perform the TXOP preemption later than the frame arriving at the STA accordingly.

[0081] In addition or alternatively, the second parameter may indicate that the TXOP preemption can be performed based on an indication or trigger from a TXOP holder. As an example, the second parameter may indicate that the timing is flexible, such as waiting for an indication. For example, the TXOP preemption is allowed after a certain frame (which may be referred to as a trigger frame) is sent or received. The trigger frame may be a control frame, a management frame or a data frame. Only as an example, the second parameter is further discussed with reference to FIG. 4.

[0082] FIG. 4 illustrates an example of a TXOP preemption timing indicated by a second parameter according to some embodiments of the present disclosure. As shown in FIG. 4, within the TXOP of 3ms, the STA may perform the TXOP preemption at the timing 410 indicated by the second parameter.

[0083] Referring back to FIG. 2, in addition or alternatively, the one or more parameters may include a third parameter (which may be also referred to as TXOP-P number of allowed users parameter in some embodiments) indicating a number of stations allowed to perform the TXOP preemption. As mentioned above, if there is no limitation on the number of stations allowed to perform the TXOP preemption, the TXOP holder may find it is in an “unfair” situation, and even cannot use its TXOP. Thus, there would be a need to define or indicate a minimum or maximum number of users to be allowed for TXOP preemption. In some embodiments, the third parameter may indicate a maximum number of stations allowed to perform the TXOP preemption.

[0084] For example, the third parameter may indicate that the maximum number of stations is three. That is, a maximum of 3 STAs can preempt a STA’s TXOP, implying that a fourth STA can’t preempt the on-going TXOP. In some embodiments, the fourth STA which is not allowed to perform a further TXOP preemption can be aware that it is not allowed by several ways. For example, the fourth STA can listen to the on-going TXOP constantly and be aware that the maximum number of allowed users achieves, thus the fourth STA will not preempt the on-going TXOP. In another example, the fourth STA may try to preempt the on-going TXOP even after the maximum number of allowed STAs (3 STAs) is achieved, but the TXOP preemption will rejected by the STA of on-going TXOP (e g., the TXOP holder). In addition, in some embodiments, the maximum number of stations is related to the number of stations, but not limit the times of TXOP preemption performed by an allowed station. Only as an example, the third parameter is further discussed with reference to FIG. 5.

[0085] In addition or alternatively, in some embodiments, the third parameter may indicate the minimum number of stations allowed to perform the TXOP preemption. For example, the number of stations which has low latency communication requirement may be predicted advance. Then, the second parameter may indicate the number of stations having the low latency communication requirement as the minimum number of stations. In addition, the second parameter may indicate a group of stations allowed to perform the TXOP preemption. In some embodiments, only the station among the group of stations is allowed to perform the TXOP preemption.

[0086] FIG. 5 illustrates an example of a number stations allowed to perform the TXOP preemption indicated by a third parameter according to some embodiments of the present disclosure.

[0087] As shown in FIG. 5, the third parameter may indicate that the maximum number of stations allowed to perform the TXOP preemption is two. In this case, the TXOP preemption 510 performed by the first STA and the TXOP preemption 520 performed by the second STA are allowed. However, the TXOP preemption 530 performed by the third STA is not allowed. Alternatively, as mentioned above, the third STA will not perform the TXOP preemption even if the LL frame arrives, since the third STA may determine that the maixumum number of stations is achieved by listening.

[0088] Referring back to FIG. 2, in addition or alternatively, these one or more parameters may include the fourth parameter (which may be also referred to as TXOP-P number of allowed preemption parameter in some embodiments) indicating an allowed number of times of the TXOP preemption. Similarly, if there is no limitation on the number of times of the TXOP preemption, the TXOP holder or other STA(s) may in the network may find themselves in an “unfair” situation, and even cannot use the TXOP. Thus, there would be a need to define or indicate a minimum or maximum number of times of TXOP preemption. In some embodiments, the fourth parameter may indicate a minimum allowed number of times of the TXOP preemption or a maximum allowed number of times of the TXOP preemption. It is understood that the fourth parameter focuses on the times of TXOP preemption rather than which STA performs the TXOP preemption. Thus, the third parameter is independent from the fourth parameter. In some embodiments, the third parameter and the fourth parameter may be used separately or together, without any limitation. That is, the third parameter defines the minimum or maximum number of users that are allowed to preempt the on-going TXOP. Moreover, the fourth parameter defines the minimum or maximum number of times of TXOP preemption.

[0089] In some embodiments, the allowed number of times of the TXOP preemption indicated by the fourth parameter may be applied to a single station or to multiple stations. For example, the fourth parameter may indicate a number that is used by a single STA. As an example, one STA can perform maximum 3 times of TXOP preemptions. This also implies that, if there are 2 STAs associated with TXOP preemption, each of them can perform maximum 3 times of TXOP preemptions. That is, STA1 can perform maximum 3 times of TXOP preemption and STA2 can perform maximum 3 times of TXOP preemption. Only for discussion purposes, the fourth number is further discussed with reference to FIG. 6A.

[0090] FIG. 6A illustrates an example of an allowed number of times of the TXOP preemption indicated by the fourth parameter according to some embodiments of the present disclosure. As shown in FIG. 6A, the fourth parameter indicates that one STA can perform maximum 2 times of TXOP preemptions. Thus, both the first STA and the second STA can perform the maximum two times of the TXOP preemption. As shown by the arrows 610 and 620, the first STA performs the TXOP preemption twice at most. As shown by arrows 630 and 640, the second STA performs the TXOP preemption twice at most.

[0091] Alternatively, the fourth parameter may indicate a number that is used by multiple STAs. In some embodiments, assuming that there are 2 STAs to perform TXOP preemption with TXOP-P number of allowed preemption = maximum 5 times. In this case, these STAs can perform maximum 5 TXOP preemptions together. Only for discussion purposes, the fourth number is further discussed with reference to FIG. 6B.

[0092] FIG. 6B illustrates another example of an allowed number of times of the TXOP preemption indicated by a fourth parameter according to some embodiments of the present disclosure. As shown in FIG. 6B, the fourth parameter indicates the maximum four times of allowed TXOP preemption. In this case, there may be at most four times of TXOP preemption in total. As shown in FIG. 6B, the first STA, the second STA and the third STA perform 4 times of TXOP preemption in total.

[0093] Referring back to FIG. 2, in addition or alternatively, the one or more parameters may include a fifth parameter (which may be also referred to as TXOP-P notification parameter in some embodiments) indicating that the TXOP preemption is performed. The fifth parameter may define a notification for STAs to understand that the TXOP is interrupted. In some scenarios, a STA needs to know whether the TXOP is preempted (interrupted), otherwise, it can’t determine what is going on. For example, the STA may still perform some meaningless operations, for example, the TXOP responder may still perform the detection of the frames from the TXOP holder while the TXOP has been preempted.

[0094] As an example, AP possesses the TXOP (i.e., TXOP holder) and transmits frames to non-AP STA1 (TXOP responder). If non-AP STA2 (non-TXOP holder) preempts AP’s TXOP, AP may notify the non-AP STA1 that AP’s TXOP is preempted. This is the reason why AP does not transmit any frames to non-AP STA1. In some embodiments, the fifth parameter may be transmitted to one or more other stations. In some embodiments, the fifth parameter may be transmitted in a Contention Free-End (CF-end) frame. Only for discussion purposes, the fifth parameter is further discussed with reference to FIG. 7.

[0095] FIG. 7 illustrates an example of a notification about the TXOP preemption indicated by the fifth parameter according to some embodiments of the present disclosure. As shown in FIG. 7, the AP station has the TXOP, i.e., the AP station is the TXOP holder, and the non-AP STA 1 is the TXOP responder. During the TXOP, a LL frame arrives the at non-AP STA2, and the non-AP STA2 performs the TXOP preemption accordingly, and starts to transmit data to the AP. Then, the AP station may transmit the fifth parameter to one or more other stations. Once receiving the fifth parameter, the TXOP responder may not expect the data from the TXOP holder any more. In addition, once receiving the fifth parameter, the other stations will perform the TXOP preemption for a period.

[0096] Referring back to FIG. 2, in addition to the use of at least one of the first to the fifth parameters in performing the TXOP preemption operation, a sixth parameter (which may be also referred to as TXOP-P indication parameter in some embodiments) may be used for indicating whether the TXOP preemption is allowed. In some embodiments, the sixth parameter may define whether TXOP preemption is allowed or not. A STA may indicate whether it accepts being preempted with the fifth parameter. As an example, the fifth parameter may include one bit and the state of the one bit may indicate whether the TXOP preemption is allowed. For example, the one bit being 0 indicates that TXOP preemption is not allowed, and the one bit being 1 indicates that the TXOP preemption is allowed. It is to be understood that this embodiment is only an example, any other value may be applied. In addition, in some embodiments, the fifth parameter may be variable in one TXOP. Only for discussion purposes, the sixth parameter is further discussed with reference to FIG. 8.

[0097] FIG. 8 illustrates an example of the TXOP preemption indication of a sixth parameter that is variable in a TXOP according to some embodiments of the present disclosure. As shown in FIG. 8, the sixth parameter may be changed during the TXOP. Specifically, in the case that the sixth parameter indicates a first state (e.g., 1), the TXOP preemption is allowed. Otherwise, in the case that the sixth parameter indicates a second state (e.g., 0), TXOP preemption is not allowed. Without any limitation, some other parameters of the one or more parameter may be also variable depending on the communication conditions.

[0098] Referring back to FIG. 2, in addition to the use of at least one of the first to the fifth parameters in performing the TXOP preemption operation a seventh parameter (which may be also referred to as TXOP-P feedback in some embodiments) may be used for indicating feedback for the TXOP preemption. The seventh parameter may define a detailed feedback mechanism for TXOP preemption operation. In some embodiments, the feedback indicated by the seventh parameter may further include some detail information with respect to the TXOP preemption in addition to the simply “accept or rejected”.

[0099] As an example, AP possesses TXOP (i.e., the AP is TXOP holder) and transmits frames to non-AP STA1 (i.e., the non-AP STA1 is TXOP responder). In this case, non-AP STA2 (which is not the TXOP holder) may preempt AP’s TXOP. Then, non-AP STA3 may also want to preempt AP’s TXOP. However, because the AP’s TXOP may be already preempted by non-AP STA2, AP can’t accept non-AP STA3’s TXOP preemption. In this case, AP may send the seventh parameter indicating a feedback to non-AP STA3, the feedback may be indicated as “another STAis performing TXOP preemption”.

[00100] In addition, in some embodiments, the seventh parameter may include an indication that a duration of the TXOP preemption requested by the first station is accepted or rejected. In addition or alternatively, the seventh parameter may include timing of the TXOP preemption requested by the first station is accepted or rejected. In addition or alternatively, the seventh parameter may include a maximum number of stations allowed to perform the TXOP preemption is achieved and / or a maximum allowed number of times of the TXOP preemption is achieved. In this way, the feedback mechanism based on the seventh parameter may provide more detail information associated with the TXOP preemption.

[00101] In some embodiments, the seventh parameter may be useful when there are hidden nodes in the network, i.e., not every STAs can hear each other. For example, the seventh parameter may be relayed to the hidden STAs. In this way, the detailed feedback may provide a consistent understanding of the current TXOP preemption situation for hidden nodes. Only for discussion purposes, the seventh parameter is further discussed with reference to FIG. 9.

[00102] FIG. 9 illustrates an example of a feedback indicated by the seventh parameter according to some embodiments of the present disclosure. As shown in FIG. 9, the AP station possesses the TXOP and transmits frames to the non-AP STA1. During the TXOP, a LL frame arrives at non-AP STA2, and the non-AP STA2 performs the TXOP preemption and transmits data accordingly. However, during the TXOP preemption duration, a LL frame also arrives at non-AP STA3. Then, the non-AP STA3 also want to perform the TXOP preemption. For example, the non-AP STA 3 may transmit a TXOP preemption request to the AP. In this case, the AP may transmit the seventh parameter indicating the feedback to the non-AP STA3, and the feedback may be indicated as that “another STA is performing TXOP preemption”.

[00103] Referring back to FIG. 2, in addition to the use of at least one of the first to the fifth parameters in performing the TXOP preemption operation an eighth parameter (which may be also referred to as TXOP-P priority parameter in some embodiments) may be used for indicating a priority level of a frame related to the TXOP preemption. That is, the eighth parameter may define which LL frames are allowed for TXOP preemption. In some cases, a STA is not allowed to preempt the on-going TXOP, because the LL requirement for that frame is not acceptable by the STA of on-going TXOP. In other words, not every LL frame should be considered for TXOP preemption. To achieve this, when a STA has a LL frame, the STA may firstly determine LL frame’s priority, so that the decision of TXOP preemption can be made based on the LL frame’s priority (TXOP preemption is accepted or rejected).

[00104] In some embodiments, the priority level indicated by the eighth parameter may be associated with the traffic type. As an example, the traffic type “access category voice (AC VO) and access category video (AC_VI)” may have the high priority level, the traffic type “access category best effort (AC BE) and access category background (AC_BK)” may have the low priority level and the other LL frame may have the normal priority LL frame. In some embodiments, if the eighth parameter indicates the normal priority level, then the TXOP preemption may be performed for the frames being of the traffic type which is above or equal to the normal priority, i.e., the AC^VO, ACV or normal priority LL frame.

[00105] In addition, in some embodiments, the priority level for performing the TXOP preemption may be related to the communication load of the TXOP holder.

[00106] As an example, AP has TXOP (TXOP holder) and is transmitting frames to non-AP STA1 (TXOP responder). When non-AP STA2 (non-TXOP holder) wants to preempt AP’s TXOP, the non-AP STA2 sends TXOP preemption request with LL frame priority so that AP can decide whether AP allows non-AP STA2 to preempt the on-going TXOP or not. For instance, if AP does not have a lot of frames to send (i.e. low load), it can accept non-AP STA2’s TXOP preemption with a low priority frame. However, if AP has a lot of frames to send (i.e. high load), it can’t accept non-AP STA2’s TXOP preemption with the low priority frame, but may accept non-AP STA2’s TXOP preemption with a high priority frame. Without any limitation, in some embodiments, the first parameter to the eighth parameters of the one or more parameters may be used for performing the TXOP preemption separately, partially or together.

[00107] Still referring to FIG. 2, these one or more parameters may be transmitted / unicast / broadcast in any frames transmitted in a wireless network. In some embodiments, the one or more parameters may be transmitted in a medium access control (MAC) frame. For example, the one or more parameters may be carried in a management frame, a control frame and / or a data frame for the MAC layer. Only as examples, the management frame may include the beacon frame in the wireless network. The control frame may include the TXOP preemption request message and TXOP preemption response message.

[00108] In addition, in some embodiments, the management frame carrying the one or more parameters may be a reused management frame, for example, an existing management frame. That is, the existing management frame may be reused to carry the one or more frames. Alternatively, a new management frame dedicated to the one or more parameter may be designed for the TXOP preemption. Similarly, the control frame or data frame may be also a new dedicated frame for the one or more parameters or the reused (for example, existing) frame.

[00109] In addition, assuming that the one or more parameters are carried in the management frame. In some embodiments, the one or more parameters may be carried in multiple alternative manners. For example, the one or more parameters may be carried in a first field or a second field of a management frame’s MAC header (which may be also referred to the first MAC header in some embodiments). Moreover, the first field may be a reused (for example, existing) field. For example, the high throughput (HT) control field of the first MAC header may be reused to carry the one or more parameters. Alternatively, the second field may be a new field dedicated to the one or more parameters. Alternatively, the one or more parameters may be carried in the MAC payload of the MAC layer frame. For example, the one or more parameters may be carried in first information element (IE) or second IE of the management frame’s MAC payload (which may be also referred to a first MAC payload). The first IE may be a reused (for example, existing) IE. That is, an existing IE of the MAC payload may be reused to carry the one or more parameters. In addition, the second IE may be a new IE dedicated to the one or more parameters.

[00110] In addition or alternatively, in some embodiments, assuming that the one or more parameters are carried in the data frame. Similarly, the one or more parameters may be carried in a third field or a fourth field of the data frame’s MAC header (which may be also referred to as a second MAC header in some embodiments). The third field may be a reused (for example, existing) field. For example, the HT control field or quality of service (QoS) control field of the second MAC header may be reused to carry the one or more parameters. Alternatively, the one or more parameters may be also in the data frame’s MAC payload (which may be also referred to as a second MAC payload) as part of data.

[00111] In addition or alternatively, in some embodiments, assuming that the one or more parameters are carried in the control frame. In an example, the one or more parameters may be carried in a fifth field or a six field of the control frame’s MAC header (which may be also referred to as the third MAC header in some embodiments). The fifth field may be a reused (for example, existing) field. That is, an existing field in the third MAC header may be reused to carry the one or more parameters. For example, the fifth field may include, but not limited to, Common info field of trigger frames, User info field of trigger frames, BAR control field in BlockAckReq, BAR information in BlockAckReq, BA control field of BlockAck and BA information field of BlockAck. The sixth field may be a new field dedicated to the one or more parameters.

[00112] In addition or alternatively to the MAC layer frame, the one or more parameters may be also carried in a physical (PHY) layer frame. For example, the one or more parameters may be included in the header of the PHY layer frame.

[00113] Only as examples of the above embodiments, the one or more parameters may be transmitted in at least one of the following: a beacon frame; a data frame; a TXOP preemption request; a TXOP preemption response; or a block acknowledgement (BACK) frame.

[00114] Only for discussion clarity, some examples of TXOP preemption performed based on the one or more parameters are discussed with reference to FIGS. 10 and 11.

[00115] FIG. 10 illustrates an example of one or more times of the TXOP preemption using one or more parameters according to example embodiments of the present disclosure;

[00116] In the example of FIG. 10, AP sends, in beacon frames 1010 (i.e., a broadcast message), the third parameter indicating a number of users allowed to perform the TXOP preemption as one and the fourth parameter indicating the number of times of TXOP preemption as one in total. This implies that only one non-AP STA is allowed to perform TXOP preemption, and that only one time TXOP preemption is allowed (in other words, one non-AP STA can interrupt TXOP only once). AP also sends TXOP-P indication (allowed) in beacon frames, implying that TXOP preemption is allowed.

[00117] AP gains access to the channel and becomes TXOP holder. Then AP starts transmitting data frame 1020 to non-AP STA1, therefore, non-AP STA1 becomes TXOP responder (i.e. transmission from AP to non-AP STA1). Moreover, non-AP STA2 and non-AP STA3 are not the TXOP holders. Non-AP STA1 sends ACK 1030 to AP after receiving data frame. In some embodiments, in data frame from the AP to non-AP STA1, the AP may send the sixth parameter indicating that TXOP preemption is allowed, implying that TXOP preemption is still allowed. Alternatively, the sixth parameter may be variable during the TXOP. For example, the AP may send the sixth parameter indicating that TXOP preemption is not allowed in some cases. In addition or alternatively, in some embodiments, the sixth parameter is not only transmitted in the data frame towards the TXOP responder, but also transmitted to other stations, e.g., the non-AP STA2 and STA3.

[00118] Afterwards, LL frame arrives at non-AP STA2 (non-TXOP holder). Non-AP STA2 sends TXOP preemption request 1040 to AP, and the TXOP preemption request 1040 may include: the first parameter indicating that TXOP-P duration = 2ms (implying that it requests to preempt TXOP for 2 ms), the second parameter indicating that TXOP-P timing = immediately (implying that TXOP preemption is needed immediately) and the eighth parameter indicating that TXOP-P priority = high priority frame (implying that its data is high priority). After receiving TXOP preemption request, AP responds to non-AP STA2 with TXOP Preemption response 1050 (ACCEPTED). The TXOP preemption response 1050 may include TXOP-P duration = 1ms &TXOP-P feedback = “Requested 2 ms is not accepted, 1ms is allocated” (implying that the requested 2ms from non-AP STA2 is not accepted -for some reasons such as AP probably has a lot of frames to sends that is why it does not want to allocate 2ms to non-AP STA2-). The response 1050 may further include TXOP-P timing = immediately (implying that AP allows non-AP STA1 to preempt TXOP immediately, i.e. sending its frames immediately). Furthermore, the response 1050 may include TXOP-P notification = “TXOP is interrupted by non-AP STA2” (implying that AP sends notification to other STAs that its TXOP is interrupted so that all STAs know it). That is, the AP may receive, from non-AP STA2, a request including at least one of a first value of the first parameter or a second value of the second parameter. Then, the AP may transmit, to the non-AP STA2, a response indicating that the at least one of the first value or the second value is accepted, rejected, or modified.

[00119] After non-AP STA2 receives TXOP preemption response 1050, it preempts AP’s TXOP and sends its data frames for 1ms (allocated by AP). AP may acknowledge these data frames with BACK.

[00120] Later on, LL frame arrives at non-AP STA3 (non-TXOP holder). Accordingly, non-AP STA3 sends another TXOP preemption request 1060 to AP. The TXOP preemption request 1060 may include the first parameter indicating that TXOP-P duration = 0.5 ms (implying that it requests to preempt TXOP for 0.5 ms), the second parameter indicating that TXOP-P timing = immediately (implying that TXOP preemption is needed immediately) and the eighth parameter indicating that TXOP-P priority = high priority frame (implying that its data is high priority). After receiving TXOP preemption request 1060, AP responds to non-AP STA1 with TXOP Preemption response 1070 (REJECTED). The response 1070 includes the seventh parameter indicating that TXOP-P feedback = “number of allowed users (1) and number of allowed preemption achieved, and another user cannot be allowed” (implying that AP does not allow non-AP STA3 to perform TXOP preemption). This is because in beacon, AP has advertised the third parameter indicating that the number of allowed users =1, and non-AP STA2 already performed TXOP preemption, hence, not other STA is allowed for TXOP preemption.

[00121] FIG. 11 illustrates another example of one or more times of the TXOP preemption using one or more parameters according to example embodiments of the present disclosure.

[00122] In the example of FIG. 11, AP sends in, beacon frames 1110, the third parameter indicating that the number of users allowed to perform the TXOP preemption as two (2) and the fourth parameter indicating that the allowed number of times of TXOP preemption as one per STA. This implies that only two non-AP STAs are allowed to perform TXOP preemption, and each of these two non-AP STAs is allowed to perform TXOP preemption once. AP also sends the sixth parameter indicating that the TXOP-P indication (allowed) in beacon frames, implying that TXOP preemption is allowed. AP also sends the first parameter indicating that TXOP-P duration = 1ms, implying that TXOP preemption should take 1 ms. AP also sends the eighth parameter indicating that TXOP-P priority = high priority frame (implying that only high priority frames are allowed for TXOP preemption).

[00123] AP gains access to the channel and becomes TXOP holder. Then AP starts transmitting data frame 1120 to non-AP STA1, therefore, non-AP STA1 becomes TXOP responder (i.e. transmission from AP to non-AP STA1). Non-AP STA1 sends ACK to AP after receiving data frame. In this case, non-AP STA2 and non-AP STA3 are not the TXOP holders. As similarly to the example in FIG. 10, in the data frame towards non-AP STA1, AP also sends the sixth parameter indicating that TXOP preemption is allowed, implying that TXOP preemption is still allowed. Moreover, the AP may also broadcast the sixth parameter.

[00124] Afterwards, LL frame arrives at non-AP STA2 (non-TXOP holder). Non-AP STA2 immediately preempts the TXOP of AP and starts sending its data frames 1130. The data frame 1130 includes the second parameter indicating that TXOP-P timing = immediately (implying that it sends it data frames immediately) and the eighth parameter indicating that TXOP-P priority = high priority frame (implying that its frames are high priority frames). In this example, non-AP STA2 does not send any TXOP preemption request, rather, non-AP STA2 directly performs TXOP preemption without permission. In addition, the non-AP STA2 sends its data frames for 1ms based on the first parameter which is advertised by AP in beacon. AP acknowledges those data frames with BACK 1140. The BACK 1140 includes the fifth parameter indicating that TXOP-P notification = “TXOP is interrupted by non-AP STA2”. In some embodiments, the BACK may be transmitted to all STAs, implying that AP sends notification to all STAs that its TXOP is interrupted so that other STAs know it. The BACK may further indicate the seventh parameter indicating that TXOP-P feedback = “number of allowed preemption achieved (for non-AP STA2). This implies that non-AP STA2 is not allowed to perform another TXOP preemption anymore, because it already used TXOP preemption once, as indicated in beacon as number of allowed preemption: 1 per STA.

[00125] Later on, LL frame arrives at non-AP STA3 (non-TXOP holder). The procedure is similar to the procedure for non-AP STA2. Non-AP STA3 immediately preempts TXOP and starts sending its data frames 1150. The data frame 1150 may include the second parameter indicating that TXOP-P timing = immediately. This implies that the non-AP STA2 sends data frames immediately. The data frame 1150 may further include the eighth parameter indicating that TXOP-P priority = high priority frame. This implies that its frames are high priority frames. Again, non-AP STA3 does not send any TXOP preemption request, rather, non-AP STA3 directly performs TXOP preemption without permission. The non-AP STA3 also sends its data frames for 1ms based on the first parameter advertised by AP in beacon. AP acknowledges those data frames with BACK 1160. The BACK 1160 may include the fifth parameter indicating that TXOP-P notification = “TXOP is interrupted by non-AP STA3”. The BACK 1160 may be transmitted to all stations. This implies that AP sends notification to all STAs that its TXOP is interrupted so that other STAs can know it. The BACK 1160 may further include the seventh parameter indicating that TXOP-P feedback = “number of allowed preemption achieved (for non-AP STA3)”. This implies that non-AP STA3 is not allowed to perform another TXOP preemption. Because the non-AP STA3 already used TXOP preemption once, as indicated in beacon as number of allowed preemption: 1 per STA. Further, BACK 1160 may further include the sixth parameter indicating that TXOP-P indication = TXOP preemption is not allowed, implying that AP does not allow any TXOP preemption from now on. Therefore, AP keeps using its TXOP to send a data frame to non-AP STA1, receiving ACK for that data frame at the end.

[00126] As mentioned above, in some embodiments, the one or more parameters may be determined per TXOP. For example, with the communication conditions changing, the one or more parameters may be different in different TXOP. In addition or alternatively, the one or more parameters may be pre-set for one or more TXOPs. That is, the one or more parameters may be fixed for the one or more TXOPs. In addition or alternatively, a first subset of parameters among the one or more parameters may be also variable in a TXOP and a second subset of parameters among the one or more parameters may be pre-set for the TXOP

[00127] In view of the above, based on the one or more parameters, the TXOP preemption may work properly and appropriately. For example, some potential “unfair” granting of TXOP can be avoided.

[00128] In some embodiments, an apparatus capable of performing any of the method 200 (for example, the terminal device) may comprise means for performing, based on one or more parameters, an operation related to transmit opportunity (TXOP) preemption. The one or more parameters comprises at least one of the following: a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption; a second parameter indicating timing of the TXOP preemption; a third parameter indicating a number of stations allowed to perform the TXOP preemption; a fourth parameter indicating an allowed number of times of the TXOP preemption; or a fifth parameter indicating that the TXOP preemption is performed. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[00129] In some embodiments, the one or more parameters may further comprise at least one of the following: a sixth parameter indicating whether the TXOP preemption is allowed; a seventh parameter indicating feedback for the TXOP preemption; or an eighth parameter indicating a priority level of a frame related to the TXOP preemption.

[00130] In some embodiments, the first parameter indicates a number of time units of the TXOP preemption or a range of the duration of the TXOP preemption.

[00131] In some embodiments, the number of time units comprises at least one of the following: a maximum number of time units, a minimum number of time units, or an intermediate number of time units between the maximum number of time units and the minimum number of time units.

[00132] In some embodiments, wherein the second parameter indicates at least one of the following: the TXOP preemption is to be performed immediately after a frame that arrives at a station ends or within a time period after the frame ends, the TXOP preemption is to be performed with a time delay after a frame arrives at a station, or the TXOP preemption is to be performed based on an indication from a TXOP holder.

[00133] In some embodiments, the third parameter indicates at least one of the following: a minimum number of stations allowed to perform the TXOP preemption; a maximum number of stations allowed to perform the TXOP preemption; or a group of stations allowed to perform the TXOP preemption.

[00134] In some embodiments, at least one of the following is performed: a station of the group of stations is above or is of an indicated station priority; or the group of stations is informed by a dedicated message.

[00135] In some embodiments, the fourth parameter indicates at least one of the following: a minimum allowed number of times of the TXOP preemption; or a maximum allowed number of times of the TXOP preemption.

[00136] In some embodiments, the allowed number of times of the TXOP preemption indicated by the fourth parameter applies to a single station or to multiple stations.

[00137] In some embodiments, the apparatus is a TXOP holder, and the operation comprises: based on determining that the TXOP preemption is performed by a station, transmitting the fifth parameter to at least one other station. In some embodiments, the fifth parameter is carried in a Contention Free-End (CF-end) frame.

[00138] In some embodiments, the apparatus is a TXOP holder, the seventh parameter is transmitted to a first station, and wherein the seven parameter comprises an indication that: a second station is performing the TXOP preemption; a duration of the TXOP preemption requested by the first station is accepted or rejected; timing of the TXOP preemption requested by the first station is accepted or rejected; a maximum number of stations allowed to perform the TXOP preemption is achieved; or a maximum allowed number of times of the TXOP preemption is achieved.

[00139] In some embodiments, the priority level indicated by the eighth parameter is associated with a traffic type. In some embodiments, the apparatus may further include: means for transmitting the one or more parameters to at least one station.

[00140] In some embodiments, the one or more parameters are transmitted in at least one of the following: a medium access control (MAC) layer frame; or a physical (PHY) layer frame.

[00141] In some embodiments, the one or more parameters are carried in at least one of a management frame, a control frame or a data frame for the MAC layer. The at least one of the management frame, the control frame or the data frame is an existing MAC layer frame or another MAC layer field dedicated to the one or more parameters.

[00142] In some embodiments, the one or more parameters are carried in the management frame, and where at least one of the following is performed: the one or more parameters are carried in a first field or a second field of a first MAC header, wherein the first field is an existing field and the second field is dedicated to the one or more parameters; or the one or more parameters are carried in first information element (IE) or second IE of a first MAC payload, wherein the first IE is an existing IE and the second IE is dedicated to the one or more parameters.

[00143] In some embodiments, the one or more parameters are carried in the data frame, and where at least one of the following is performed: the one or more parameters are carried in a third field or a fourth field of a second MAC header, wherein the third field is an existing field and the fourth field is dedicated to the one or more parameters; or the one or more parameters are carried in a second MAC payload as part of data.

[00144] In some embodiments, the one or more parameters are carried in the control frame, and where at least one of the following is performed: the one or more parameters are carried in a fifth field or a sixth field of a third MAC header, wherein the fifth field is an existing field and the sixth field is dedicated to the one or more parameters.

[00145] In some embodiments, the one or more parameters are carried in a PHY header of the PHY layer frame. In some embodiments, the one or more parameters are transmitted in at least one of the following: a beacon frame; a data frame; a TXOP preemption request; a TXOP preemption response; or a block acknowledgement (BACK) frame.

[00146] In some embodiments, the apparatus is a TXOP holder, and the operation comprises: receiving, from a station, a request including at least one of a first value of the first parameter or a second value of the second parameter; and transmitting, to the station, a response indicating that the at least one of the first value or the second value is accepted, rejected, or modified.

[00147] In some embodiments, the apparatus is a TXOP holder, and the operation comprises: receiving, from a station, a request for the TXOP preemption, wherein the request includes the eighth parameter indicating the priority level of the frame related to the TXOP preemption; and accepting or rejecting the request based on at least one of the priority level of the frame or communication requirement of the apparatus.

[00148] In some embodiments, the apparatus is a TXOP holder, and the operation comprises: receiving, from a station, a request for the TXOP preemption; and accepting or rejecting the request based on at least one of the third parameter or the fourth parameter.

[00149] In some embodiments, at least one of the following is performed: the one or more parameters are determined per TXOP; the one or more parameters are pre-set for one or more TXOPs; or a first subset of parameters among the one or more parameters is variable in a TXOP and a second subset of parameters among the one or more parameters is pre-set for the TXOP.

[00150] In some embodiments, the apparatus is one of the following: an access point (AP) station; a non-AP station; a TXOP holder; a TXOP responder; or a station configured to perform the TXOP preemption.

[00151] FIG. 12 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure. The device 1200 may be provided to implement the communication device, for example the terminal device or the network device. As shown, the device 1200 includes one or more processors 1210, one or more memories 1220 coupled to the processor 1210, and one or more communication modules 1240 coupled to the processor 1210.

[00152] The communication modules 1240 is for bidirectional communications. The communication modules 1240 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[00153] The processor 1210 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1200 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[00154] The memory 1220 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1324, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1222 and other volatile memories that will not last in the power-down duration. The memory 1120 may have instructions, such as for example a computer program, stored thereon.

[00155] A computer program 1230 includes computer executable instructions that are executed by the associated processor 1210. The program 1230 may be stored in the ROM 1224. The processor 1310 may perform any suitable actions and processing by loading the program 1230 into the RAM 1222.

[00156] The embodiments of the present disclosure may be implemented by means of the program 1230 so that the device 1200 may perform any process of the disclosure as discussed with reference to FIGS. 2 to 12. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[00157] In some embodiments, the program 1230 may be tangibly contained in a computer readable medium which may be included in the device 1200 (such as in the memory 1220) or other storage devices that are accessible by the device 1200. The device 1200 may load the program 1230 from the computer readable medium to the RAM 1222 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. FIG. 13 shows an example of the computer readable medium 1300 in form of CD or DVD. The computer readable medium has the program 1230 stored thereon.

[00158] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[00159] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 200 as described above with reference to FIGS. 2 to 11. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[00160] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[00161] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[00162] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e g., RAM vs. ROM).

[00163] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

[00164] Although the present disclosure has been described in languages specific to 5 structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. An apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:perform, based on one or more parameters, an operation related to transmit opportunity, TXOP, preemption,wherein the one or more parameters comprise at least one of the following:a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption;a second parameter indicating timing of the TXOP preemption;a third parameter indicating a number of stations allowed to perform the TXOP preemption;a fourth parameter indicating an allowed number of times of the TXOP preemption; ora fifth parameter indicating that the TXOP preemption is performed.

2. The apparatus of claim 1, wherein the one or more parameters further comprise at least one of the following:a sixth parameter indicating whether the TXOP preemption is allowed;a seventh parameter indicating feedback for the TXOP preemption; oran eighth parameter indicating a priority level of a frame related to the TXOP preemption.

3. The apparatus of claim 1 or 2, wherein the first parameter indicates a number of time units of the TXOP preemption or a range of the duration of the TXOP preemption.

4. The apparatus of claim 3, wherein the number of time units comprises at least one of the following:a maximum number of time units,a minimum number of time units, oran intermediate number of time units between the maximum number of time units and the minimum number of time units.

5. The apparatus of any of claims 1-4, wherein the second parameter indicates at least one of the following:the TXOP preemption is to be performed immediately after a frame that arrives at a station ends or within a time period after the frame ends,the TXOP preemption is to be performed with a time delay after a frame arrives at a station, orthe TXOP preemption is to be performed based on an indication from a TXOP holder.

6. The apparatus of any of claims 1-5, wherein the third parameter indicates at least one of the following:a minimum number of stations allowed to perform the TXOP preemption;a maximum number of stations allowed to perform the TXOP preemption; ora group of stations allowed to perform the TXOP preemption.

7. The apparatus of claim 6, wherein at least one of the following is performed: a station of the group of stations is above or is of an indicated station priority; or the group of stations is informed by a dedicated message.

8. The apparatus of any of claims 1-7, wherein the fourth parameter indicates at least one of the following:a minimum allowed number of times of the TXOP preemption; or a maximum allowed number of times of the TXOP preemption.

9. The apparatus of any of claims 1-8, wherein the allowed number of times of the TXOP preemption indicated by the fourth parameter applies to a single station or to multiple stations.

10. The apparatus of any of claims 1-9, wherein the apparatus is a TXOP holder, and the operation comprises:based on determining that the TXOP preemption is performed by a station, transmitting the fifth parameter to at least one other station.

11. The apparatus of claim 10, wherein the fifth parameter is carried in a Contention Free-End, CF-end, frame.

12. The apparatus of any of claims 2-11, wherein the apparatus is a TXOP holder, the seventh parameter is transmitted to a first station, and wherein the seven parameter comprises an indication that:a second station is performing the TXOP preemption;a duration of the TXOP preemption requested by the first station is accepted or rejected;timing of the TXOP preemption requested by the first station is accepted or rejected;a maximum number of stations allowed to perform the TXOP preemption is achieved; ora maximum allowed number of times of the TXOP preemption is achieved.

13. The apparatus of any of claims 2-12, wherein the priority level indicated by the eighth parameter is associated with a traffic type.

14. The apparatus of any of claims 1-13, wherein the apparatus is further configured to:transmit the one or more parameters to at least one station.

15. The apparatus of claim 14, wherein the one or more parameters are transmitted in at least one of the following:a medium access control, MAC, layer frame; ora physical, PHY, layer frame.

16. The apparatus of claim 15, wherein:the one or more parameters are carried in at least one of a management frame, a control frame or a data frame for the MAC layer,wherein the at least one of the management frame, the control frame or the data frame is an existing MAC layer frame or another MAC layer field dedicated to the one or more parameters.

17. The apparatus of claim 16, wherein the one or more parameters are carried in the management frame, and where at least one of the following is performed:the one or more parameters are carried in a first field or a second field of a first MAC header, wherein the first field is an existing field and the second field is dedicated to the one or more parameters; orthe one or more parameters are carried in first information element, IE, or second IE of a first MAC payload, wherein the first IE is an existing IE and the second IE is dedicated to the one or more parameters.

18. The apparatus of claim 16, wherein the one or more parameters are carried in the data frame, and where at least one of the following is performed:the one or more parameters are carried in a third field or a fourth field of a second MAC header, wherein the third field is an existing field and the fourth field is dedicated to the one or more parameters; orthe one or more parameters are carried in a second MAC payload as part of data.

19. The apparatus of claim 16, wherein the one or more parameters are carried in the control frame, and where at least one of the following is performed:the one or more parameters are carried in a fifth field or a sixth field of a third MAC header, wherein the fifth field is an existing field and the sixth field is dedicated to the one or more parameters.

20. The apparatus of claim 15, wherein the one or more parameters are carried in a PHY header of the PHY layer frame.

21. The apparatus of any of claim 14 to 20, wherein the one or more parameters are transmitted in at least one of the following:a beacon frame;a data frame;a TXOP preemption request;a TXOP preemption response; ora block acknowledgement, BACK, frame.

22. The apparatus of any of claims 1-21, wherein the apparatus is a TXOP holder, and the operation comprises:receiving, from a station, a request including at least one of a first value of the first parameter or a second value of the second parameter; andtransmitting, to the station, a response indicating that the at least one of the first value or the second value is accepted, rejected, or modified.

23. The apparatus of any of claims 2-22, wherein the apparatus is a TXOP holder, and the operation comprises:receiving, from a station, a request for the TXOP preemption, wherein the request includes the eighth parameter indicating the priority level of the frame related to the TXOP preemption; andaccepting or rejecting the request based on at least one of the priority level of the frame or communication requirement of the apparatus.

24. The apparatus of any of claims 1-23, wherein the apparatus is a TXOP holder, and the operation comprises:receiving, from a station, a request for the TXOP preemption; andaccepting or rejecting the request based on at least one of the third parameter or the fourth parameter.

25. The apparatus of any of claims 1-24, wherein at least one of the following is performed:the one or more parameters are determined per TXOP;the one or more parameters are pre-set for one or more TXOPs; ora first subset of parameters among the one or more parameters is variable in a TXOP and a second subset of parameters among the one or more parameters is pre-set for the TXOP.

26. The apparatus of any of claims 1-25, wherein the apparatus is one of the following: an access point (AP) station;a non-AP station;a TXOP holder;a TXOP responder; ora station configured to perform the TXOP preemption.

27. A method comprising:performing, based on one or more parameters, an operation related to transmit5 opportunity (TXOP) preemption,wherein the one or more parameters comprise at least one of the following:a first parameter indicating at least one of a duration of the TXOP preemption or a periodicity of the TXOP preemption;a second parameter indicating timing of the TXOP preemption;10 a third parameter indicating a number of stations allowed to perform theTXOP preemption;a fourth parameter indicating an allowed number of times of the TXOP preemption; ora fifth parameter indicating that the TXOP preemption is performed.

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