CN116803184A - Preemption/interruption of an ongoing low priority PPDU - Google Patents

Abstract

A Wireless Local Area Network (WLAN) having Stations (STAs) that use carrier sense multiple access/collision avoidance (CSMA/CA), wherein at least some of the stations support Full Duplex (FD) transmissions. Mechanisms are described in which a STA may send a preemption request to a station that performs an ongoing transmission. The preempted STA detects a preemption request for the preempted STA. The preempted STA interrupts its ongoing transmission if it has determined to accept the preemption request. In this way, the preempted STA, upon receiving notification that the preempted STA has interrupted its ongoing transmission, preempts the transmission of the preempted STA to send a preempted transmission.

Description

Preemption/interruption of an ongoing low priority PPDU

Cross Reference to Related Applications

The present application claims priority and benefit from U.S. patent application Ser. No. 17/820,454, filed 8/17 2022, which is incorporated herein by reference in its entirety. The present application claims priority and benefit from U.S. provisional patent application Ser. No. 63/261,213, filed on 9/15 of 2021, incorporated herein by reference in its entirety.

Statement regarding federally sponsored research or development

Is not suitable for

Notification of copyrighted material

A portion of the material in this patent document may be subject to copyright protection in accordance with the copyright laws of the united states and other countries. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. patent and trademark office patent file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not disclaim any rights to the patent document, including but not limited to the rights it enjoys in accordance with 37c.f.r. ≡1.14.

Technical Field

The technology of the present disclosure relates generally to wireless network communications, and more particularly to protocols that allow preemption and/or interruption of ongoing lower priority data.

Background

Stations on the network transmit and receive physical layer Protocol Data Units (PDUs) in a Wireless Local Area Network (WLAN). Some of these stations are configured to perform full duplex communications in which they transmit and receive simultaneously.

However, high priority traffic is often hampered by these ongoing communications.

Accordingly, the present disclosure overcomes this problem and provides additional benefits.

Disclosure of Invention

During ongoing communications between Stations (STAs), there are instances when higher priority traffic is being blocked by these ongoing transmissions. For example, assume that an STA denoted as STA a has Full Duplex (FD) capability and is transmitting a PPDU; while another STA, denoted STA B, has higher priority traffic to send. The present disclosure describes mechanisms that allow STA B to request an interrupt and, in some cases, preempt STA a's transmissions.

Further aspects of the technology described herein will be brought out in the following sections of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the technology without placing limitations thereon.

Drawings

The technology described herein will be more fully understood by reference to the following drawings, which are for illustrative purposes only:

fig. 1 is a block diagram of self-interference cancellation (SIC) hardware on a wireless station in accordance with at least one embodiment of the present disclosure.

Fig. 2 is a hardware block diagram of wireless Station (STA) hardware in accordance with at least one embodiment of the present disclosure.

Fig. 3 is a hardware block diagram of a station configuration, such as contained in multi-link device (MLD) hardware, in accordance with at least one embodiment of the present disclosure.

Fig. 4 is an example network topology for demonstration purposes in accordance with at least one embodiment of the present disclosure.

Fig. 5 is a flow diagram of a transmitter STA transmitting a PPDU with puncturing resources to assist a receiver and other STAs in detecting third party transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 6 is a flow chart of detecting third party transmissions by a STA upon receipt of a PPDU in accordance with at least one embodiment of the present disclosure.

Fig. 7 is a communication diagram of detecting third party transmissions based on channel conditions in accordance with at least one embodiment of the present disclosure.

Fig. 8 is a communication diagram of a transmitter STA signaling on a punctured resource to notify other STAs of its third party transmission detection in accordance with at least one embodiment of the present disclosure.

Fig. 9 is a communication diagram of an STA detecting a third party transmission on partial channel resources in accordance with at least one embodiment of the present disclosure.

Fig. 10 and 11 are flowcharts of FD originator STA initiating full duplex transmission according to at least one embodiment of the present disclosure.

Fig. 12 is a flow chart of an FD receiver STA initiating full duplex transmission in accordance with at least one embodiment of the present disclosure.

Fig. 13 is a communication diagram of full duplex transmission of PPDU1 in accordance with at least one embodiment of the present disclosure.

Fig. 14 is a communication diagram of full duplex partial channel transmission in accordance with at least one embodiment of the present disclosure.

Fig. 15 is a flow chart of an FD initiator STA interrupting its ongoing full duplex transmission in accordance with at least one embodiment of the present disclosure.

Fig. 16 is a flow chart of an FD recipient STA interrupting its ongoing full duplex transmission in accordance with at least one embodiment of the present disclosure.

Fig. 17 is a flow diagram of a preempting STA initiating a preemption transmission in accordance with at least one embodiment of the present disclosure.

Fig. 18 is a flow diagram of a preempted STA accepting or rejecting preempted transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 19 is a communication diagram of a first example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 20 is a communication diagram of a second example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 21 is a communication diagram of a third example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 22 is a communication diagram of a fourth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 23 is a communication diagram of a fifth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 24 is a communication diagram of a sixth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 25 is a communication diagram of a seventh example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 26 is a communication diagram of an eighth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 27 is a communication diagram of a ninth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 28 is a communication diagram of a tenth example of preempting and/or interrupting FD transmissions in accordance with at least one embodiment of the present disclosure.

Fig. 29 is a data field diagram of an FD PPDU format that may be used for FD transmission and preemption in accordance with at least one embodiment of the present disclosure.

Fig. 30 is a data field diagram of a DTX acknowledgement signal format in accordance with at least one embodiment of the present disclosure.

Fig. 31 is a data field diagram of a preemption request signal format in accordance with at least one embodiment of the present disclosure.

Detailed Description

1. Station hardware and network topology

The present disclosure describes apparatus and methods for wireless network communication between stations performing carrier sense multiple access/collision avoidance protocols under 802.11.

1.1. FD station with self-interference cancellation (SIC)

Station hardware of stations providing Full Duplex (FD) operation typically has a Radio Frequency Front End (RFFE) 30 that provides self-interference cancellation (SIC) as already described in Sony's previous FD STA applications.

Fig. 1 illustrates an example embodiment 10 of self-interference cancellation (SIC) hardware for use in a station having a Radio Frequency Front End (RFFE) 30. The SIC hardware is used for Wireless Local Area Networks (WLANs), such as the STA seen in fig. 2 below and the MLD seen in fig. 3.

The transmit digital BB 12 is a baseband Transmit (TX) signal. The baseband digital signal is modulated into a passband signal by a digital-to-analog converter (DAC) and an up-converter (UC) 14 to accumulate harmonic and transmitter noise. A small portion of the transmit signal, including the transmitter noise, passes through circuit 15 to make an analog SIC before going to TX antenna 16.

The SIC circuit consists of parallel fixed lines 26a to 26n of varying delay and adjustable attenuators 28a to 28 n. These lines are then collected and added up and the combined signal is then subtracted 23 from the signal on the receive path.

The passband signal received from antenna 22 is applied 23SIC correction and passed through an analog-to-digital converter (ADC) and a down-converter (dc) 20. Digital SIC 24 is applied 19 to the baseband digital signals from the ADC and DC to estimate the remaining residual self-interference (which includes the main TX SI after analog cancellation and any delayed reflection of the signal from the environment) to produce receiver digital baseband signal 18.

Fig. 2 illustrates an example embodiment 50 of STA hardware configured to perform the protocols of the present disclosure. The external I/O connection 54 is preferably coupled to an internal bus 56 of the circuit 52, the internal bus 56 having a CPU 58 and memory (e.g., RAM) 60 connected thereto for executing program(s) implementing the communication protocol. The host houses at least one modem 62 to support communication coupled to at least one RF module 64, 68, the RF modules 64, 68 each being connected to one or more antennas 69, 66a, 66b, 66 c-66 n. An RF module having multiple antennas (e.g., an antenna array) allows beamforming to be performed during transmission and reception. In this way, STAs may transmit signals using multiple sets of beam patterns.

Bus 54 allows various devices to be connected to the CPU, such as to sensors, actuators, and the like. Instructions from the memory 60 are executed on the processor 58 to execute a program implementing a communication protocol that is executed to allow the STA to perform the functions of an Access Point (AP) station or a regular station (non-AP STA). It should also be appreciated that programming is configured to operate in different modes (TXOP holder, TXOP sharing participant, source, intermediary, destination, first AP, other AP, station associated with first AP, station associated with other AP, coordinator, AP in OBSS, STA in OBSS, etc.), depending on the role it performs in the current communication context.

Thus, STA HW is shown configured with at least one modem and associated RF circuitry for providing communication over at least one frequency band. The present disclosure is primarily directed to the sub 6GHz band.

It should be appreciated that the present disclosure may be configured with a plurality of modems 62, each coupled to any number of RF circuits. In general, the use of a greater number of RF circuits will result in a wider coverage of the antenna beam direction. It should be appreciated that the number of RF circuits and the number of antennas utilized is determined by the hardware constraints of the particular device. When the STA determines that it is not necessary to communicate with a nearby STA, the RF circuitry and a portion of the antenna may be disabled. In at least one embodiment, the RF circuitry includes a frequency converter, an array antenna controller, and the like, and is connected to a plurality of antennas that are controlled to perform beamforming for transmission and reception. In this way, STAs may transmit signals using multiple sets of beam patterns, each beam pattern direction being considered an antenna sector.

Further, it will be noted that multiple instances of station hardware as shown may be combined into a multi-link device (MLD) that will typically have a processor and memory for coordinating activity, however, each STA within the MLD does not always require a separate CPU and memory.

Fig. 3 shows an example embodiment 70 of a multi-link device (MLD) hardware configuration. The MLD may include a soft AP MLD, which is an MLD composed of one or more dependent STAs operating as an AP. Soft AP MLD should support multiple radio operations at 2.4GHz, 5GHz and 6 GHz. Among the multiple radios, the basic link set is a link pair satisfying Simultaneous Transmission and Reception (STR) modes, such as a basic link set (2.4 GHz and 5 GHz), a basic link set (2.4 GHz and 6 GHz).

A conditional link is a link that forms a non-simultaneous transmit and receive (NSTR) link pair with a base link or links. For example, these links may include a 6GHz link as a conditional link corresponding to a 5GHz link when the 5GHz link is a base link; when 6GHz is the base link, the 5GHz link is a conditional link corresponding to the 6GHz link. Soft APs are used in different scenarios, including Wi-Fi hotspots and network sharing.

Multiple STAs are affiliated with one MLD, each STA operating on a different frequency link. The MLD has external I/O access to application programs, which access is connected to an MLD management entity 78 having a CPU 92 and memory (e.g., RAM) 94 to allow execution of program(s) implementing a communication protocol at the MLD level. The MLD may distribute tasks to and collect information from each of the dependent stations (illustrated here as STA1 72, STA2 74 through sta_n76) to which it is connected and share information among the dependent STAs.

In at least one embodiment, each STA of the MLD has its own CPU 80 and memory (RAM) 82, the CPU 80 and RAM 82 being coupled to at least one modem 84 by a bus 88, the modem 84 being connected to at least one RF circuit 86, the RF circuit 86 having one or more antennas. In this example, the RF circuit has a plurality of antennas 90a, 90b, 90c to 90n, such as in an antenna array. A modem in combination with RF circuitry and associated antenna or antennas transmits/receives data frames to a nearby STA. In at least one implementation, the RF module includes a frequency converter, an array antenna controller, and other circuitry for interfacing with its antenna.

It should be appreciated that each STA of the MLD does not necessarily need its own processor and memory, as the STAs may share resources with each other and/or with the MLD management entity, depending on the particular MLD implementation. It should be appreciated that the above MLD diagram is given by way of example and not limitation, and that the present disclosure may operate with a wide range of MLD implementations.

1.2. Example network topology

Fig. 4 shows an example embodiment 110 of a network topology used in the examples by way of illustration and not by way of limitation, as well as other topologies illustrated herein. In this example, stations are shown in a communication area 112, such as a room or building, which may have an aperture (door/window) 114, within which a plurality of Stations (STAs), illustrated as 116, 118, 120 and 122, may be located. Among these STAs, STA a 116 and STA C120 are capable of Full Duplex (FD) transmission. All of these STAs are competing for channel access using CSMA/CA.

2.0. Full duplex stations using CSMA/CA.

Consider a Full Duplex (FD) STA that contends for a channel using CSMA/CA. The FD STA can transmit and receive a physical layer protocol data unit (PPDU) through the same channel at the same time.

2.1. Statement of problem

The following occurs: wherein the STA represented here by STA a is transmitting a PPDU, at which time another STA represented by STA B having a higher priority request will benefit from interrupting the ongoing transmission of STA a and preempting the transmission of STA a. This may prove particularly beneficial when STA B has a significantly higher priority PPDU to transmit than the ongoing PPDU of STA a. Suppose STA a is able to perform FD transmission, and STA B may also be able to perform FD transmission.

The method describes a method that allows STA B to request preemption of STA a's ongoing transmissions.

2.2. The terms used

FD initiator STA: and a STA that starts PPDU transmission and allows full duplex transmission during the PPDU transmission.

FD receiver STA: and a STA allowed to transmit a PPDU to the FD initiator STA for full duplex transmission during the PPDU transmission of the FD initiator.

Preempting STA: an STA that transmits a preemption request for preempting an ongoing transmission by a preempted STA. The PPDU transmission of the preempting STA that is requested to preempt the ongoing transmission of the preempted STA is denoted as a preempting transmission.

Preempted STA: and the STA receives the preemption request and schedules preemption transmission of the preempting STA.

It should be noted that in at least one embodiment, the FD receiver STA or preempted STA cannot be a preempt STA.

3. Third party transmission detection

This section considers the scenario where one STA sends a PPDU to another STA. The STA transmitting the PPDU is denoted as a transmitter STA, and the STA being an intended receiver of the PPDU is denoted as a receiver STA. Other STAs are STAs that are not transmitter STAs nor receiver STAs, and are therefore considered "third parties".

A mechanism is described to detect a third party transmission, such as an STA detecting another PPDU transmission during the time that a transmitter STA is transmitting PPDUs on the same channel. The third party transmission detection may help the receiver STA and other STAs identify whether two PPDUs are transmitted at the same time. If the transmitter STA is FD-capable, the receiver STA or other STA may send a PPDU to the transmitter STA when no third party transmission is detected. When the third party transmission is detected, the receiver STA or another STA should not transmit the PPDU to the transmitter STA for the following reasons. The PPDU transmitted by the receiver STA or another STA interferes with the third party transmission. The transmitter STA cannot receive the PPDU transmitted by the receiver STA or another STA if hearing (receiving) the third party transmission.

One practical use of such third party transmission detection is to initiate a preemption transmission as will be described later.

When the transmitter STA has FD capability, it can detect the third party transmission because it can receive while it is transmitting. However, for the receiver STA and other STAs, they cannot receive two PPDUs at the same time even though they have FD capability. Accordingly, this section proposes a solution for the receiver STA and other STAs to detect third party transmission detection.

This section proposes that the transmitter STA leave some of the puncturing resources of the (reserved) channel empty when it sends a PPDU. It should be appreciated that "puncturing" is an optional feature introduced in 802.11ax to improve spectral efficiency by allowing transmission of "punctured" portions of the spectrum channels in the event that certain channels are being used by legacy users. In this disclosure, puncturing resources are used for different purposes.

Since the PPDU is not transmitted through the puncturing resource, when the transmitter STA is the only STA transmitting the PPDU, the receiver STA and other STAs sense that the channel is idle during the puncturing resource. When there is a third party transmission over the punctured resource, the receiver STA and the other STA sense that the channel is busy during the puncturing of the resource and detect the third party transmission.

This section also proposes that when the transmitter STA is transmitting a PPDU and detects a third party transmission, it can send information over the punctured resources to indicate its third party transmission detection. The receiver STA and the other STA may then recognize that the transmitter STA is not able to receive PPDUs from them due to such third party transmissions.

A method is detailed in which a receiver STA and other STAs detect third party transmissions; such as transmissions initiated by STAs other than the transmitter STA during the time that the transmitter STA is transmitting PPDUs to the receiver.

4. Embodiments of third party detection

4.1. Third party transmission detection

Fig. 5 illustrates an example embodiment 130 of a transmitter STA transmitting a PPDU with puncturing resources, which may help a receiver STA as well as other STAs detect third party transmissions during PPDU transmission times.

The transmitter STA transmits 132 a PPDU to the receiver STA. The transmitter STA designates 134 and indicates the location of the puncturing resource in its PPDU. For example, as shown in fig. 29, the location of the puncturing resource is signaled in the preamble of the PPDU. The PPDU is transmitted 136 through a channel without using the puncturing resource.

A check 138 determines whether the transmitter STA is capable of full duplex transmission and detects CCA busy during PPDU transmission. If the condition is met, the STA may signal 140 (not part of the PPDU transmission) through the puncturing resource to indicate that a third party transmission is present. Otherwise, at block 142, the transmitter STA does not transmit the signal over the puncturing resource.

The puncturing resource may be any type of channel resource capable of carrying signals during the PPDU. For example, the puncturing resources may be in terms of RU, OFDM symbols, and/or tones of carriers. For example, if the punctured resources are per RU, the transmitter does not transmit a signal through the RU for a certain period of time. If the puncturing resources are in terms of OFDM symbols, the transmitter does not transmit a signal for several OFDM symbol durations. If the puncturing resource is based on the tone of the carrier, the transmitter does not transmit a signal over the tone for a certain period of time. The puncturing resources may be periodically embedded during PPDU transmission. It should be noted that the puncturing resource signal is possibly carried by the preamble of the PPDU. The location of the puncturing resources may be randomly determined by the transmitter according to each PPDU.

In at least one embodiment/mode/option, the puncturing resources on different channel frequencies must be located in the same channel time period. In at least one embodiment/mode/option, the puncturing resources on the different frequencies should begin and/or end at the same time.

Fig. 6 illustrates an example embodiment 150 of a STA detecting a third party transmission when receiving 152 a PPDU with location information of puncturing resources in the received PPDU. It will be noted that the STA may or may not be the intended receiver of the PPDU.

Then, a check 154 determines the results of STA channel sensing on the punctured resources. If the STA senses CCA busy on the punctured resource, then at block 156, a third party transmission is registered. The third party detection indicates that STAs other than the transmitter STA of the PPDU are transmitting at the same time. If the punctured resource is located on a partial channel (such as an RU), then the STA recognizes that there is a third party transmission on the partial channel. Otherwise, if there is no third party transmission, block 158 is reached and the process ends.

4.2.1. Example 1 of third party detection

Fig. 7 illustrates an example embodiment 170 of a process for detecting third party transmissions based on channel conditions during puncturing of resources. The communication diagram is shown with STA a 172, STA B174, and STA C176.

As shown, STA a 172 is a transmitter STA that transmits PPDU1182, PPDU1182 has its preamble 180 and has puncturing resources 186 and 188.STA C176 is interested in transmitting to STA a and performs third party transmission detection during PPDU1 transmissions. No third party transmissions 186 are initially detected. If STA C detects CCA busy 188 during the puncturing of the resources, this indicates that there is a third party transmission and therefore STA C cannot transmit to STA a. Otherwise, STA C may transmit to STA a.

This example shows how STA C detects 188 a third party transmission during the transmission time of PPDU1, e.g., there is a PPDU2192 with a preamble 190 as sent by STA B. It should be noted that the arrow shown in the figure indicates that STA C receives (hears) information of PPDU transmission from STA a or STA B.

As shown, STA a transmits a PPDU with puncturing resources, PPDU1 182.STA C receives and decodes PPDU1; and it should be recognized that STA C may decide to decode only the preamble of PPDU1 to obtain puncturing resource information. Thus, STA C has obtained the position of the puncturing resource during PPDU1 and performs channel sensing on the puncturing resource. When only STA a is transmitting, STA C senses that the channel is clear (no CCA busy) during the puncturing of the resources 186. If there is another STA (i.e., STA B174) transmitting PPDU2 (shown as PPDU2 192) while STA a is transmitting, then STA C senses CCA busy (with CCA busy) during the puncturing resource 188. As a result, STA C cannot preempt STA a. It will be noted that STA C may or may not be the intended receiver of PPDU 1.

It is possible that STA B transmits PPDU2192 when STA B is the intended receiver of PPDU1 and is transmitting PPDU2 for full duplex transmission, or when STA a is a hidden node with respect to STA B, or when PPDU2 is a preemption request transmitted by STA B.

4.2.2. Example 2 of third party detection

Fig. 8 illustrates an example embodiment 210 in which a transmitter STA sends a signal on a punctured resource to notify other STAs of its third party transmission detection. The STAs involved are the same as those of fig. 7.

As shown, STA a is a transmitter STA that transmits PPDU1182, PPDU1182 has its preamble 180 and has at least one puncturing resource 186 and 188 shown at different times. STA C is interested in transmitting to STA a and performs third party transmission detection during PPDU1 transmission 182. If STA C detects CCA busy 188 during the puncturing of resources, it detects a third party transmission and cannot transmit to STA a. Otherwise, STA C may transmit to STA a. This example illustrates the following manner: STA a detects a third party transmission (such as PPDU2 192 with preamble 190 transmitted by STA B) during the transmission time of PPDU1 and forwards this third party transmission information on the punctured resources to inform STA C if STA a detects 212 the third party transmission. Otherwise, STA a does not transmit the signal on the puncturing resource. It will be noted that the arrow shown in the figure indicates that STA C overhears (receives) a PPDU transmission from either STA a or STA B.

This example shows that the transmitter STA sends a signal on the punctured resources of PPDU1 to inform STA C of the third party transmission. As shown, STA a transmits a PPDU, i.e., PPDU1 with puncturing resources. STA C hears and decodes PPDU1.STA C has thus obtained the location of the punctured resource of PPDU1 and performs channel sensing on the punctured resource.

When only STA a is transmitting, STA C senses that the channel is clear (no CCA busy) during the puncturing of the resources 186. If there is another STA, such as STA B transmitting PPDU2, while STA a is transmitting, STA C does not sense CCA busy on the puncturing resource because it is a hidden node with respect to STA B. However, STA a hears PPDU2 transmission. During the time of PPDU2 transmission, STA a sends a signal on the puncturing resource to indicate that there is a third party transmission (i.e., PPDU 2), and it cannot receive a signal during this time (e.g., from STA C). STA C then stops attempting to preempt STA a.

It should be noted that STA C may or may not be the intended receiver of PPDU 1.

4.2.3. Example 3 third party detection

Fig. 9 illustrates an example embodiment 230 in which a STA detects a third party transmission on a portion of a channel resource. The STA involved is the same as that shown in fig. 8.

As shown, STA a is a transmitter STA that transmits PPDU1182, PPDU1182 has its preamble 180 and has at least one puncturing resource. STA C is interested in transmitting to STA a and performing third party transmission detection during PPDU1 transmissions. No CCA busy is initially detected 186 on the punctured resource. If STA C detects CCA busy 188 during the punctured resource, it recognizes that a third party transmission is in progress and cannot transmit to STA a on the portion of the channel where the punctured resource is located. Meanwhile, STA C may transmit to STA a on a portion of the channel where STA C senses the puncturing resource as idle. This example shows how STA C detects the third party transmission sent by STA B, PPDU2 232 with preamble 190, during the transmission time of PPDU 1. It should be noted that the arrow shown in the figure indicates that STA C overhears the PPDU transmission from STA a or B (receives information about it).

As shown, STA a transmits a PPDU, illustrated as PPDU1 with puncturing resources. STA C hears and decodes PPDU1. Therefore, STA C knows the location of (has information about) the punctured resource of PPDU1 and performs (runs) channel sensing on the punctured resource. When only STA a is transmitting, STA C senses channel idle (no CCA busy) during the puncturing resource at time 186. If another STA (i.e., STA B) transmits PPDU2 232 while STA a is transmitting on some RUs, STA C senses CCA busy 188 (with CCA busy) on the punctured resources on those RUs. Then, STA C cannot transmit to STA a using those RUs in which the puncturing resource is CCA busy. STA C may utilize other RUs whose punctured resources are idle, such as for performing preemption.

It should be appreciated that STA C may or may not be the intended receiver of PPDU1.

5.0. Full Duplex (FD) transmission method

This section describes a method of enabling full duplex transmission between two full duplex capable STAs. When full duplex transmission is initiated, the FD initiator STA indicates the start of full duplex transmission in its preamble of the PPDU sent to the FD receiver STA. The FD receiver STA receives the preamble of the PPDU and recognizes that it is the FD receiver STA. It then starts sending PPDUs to FD initiator STAs for full duplex transmission.

This section also discusses self-interference estimation by FD receiver STAs. When the FD initiator STA transmits a PPDU allowing FD transmission, it transmits a signal after a preamble of the PPDU. The signal may be as follows. (a) The signal is predetermined and identified by the FD receiver STA so that the FD receiver STA can cancel the signal and obtain a self-interference estimate. (b) The signal may be orthogonal to the PPDU to be transmitted by STA C so that STA C does not need to cancel the signal but performs self-interference estimation.

This section also describes a mechanism in which an FD initiator STA may request an FD receiver STA to leave some RUs empty (not used for transmission) so that other STAs may send preemption requests and optionally related information on those RUs.

Fd transmission

5.1.1. FD transmission from initiator STA

Fig. 10 and 11 illustrate an example embodiment 250 of FD initiator STA initiating full duplex transmission. The FD initiator STA sends 252 a PPDU to the FD receiver STA; and it indicates whether FD transmission is allowed in the PPDU within the PPDU.

It determines 254 whether full duplex transmission is to be allowed during PPDU transmission. If FD is not allowed, execution moves to block 266 of FIG. 11 where the FD initiator indicates that FD is not allowed in the PPDU and the process ends. It should be noted that the FD initiator may use a legacy preamble (without FD transmission parameter settings) to indicate that FD transmission is not allowed.

Otherwise, if FD is allowed at block 254, the FD initiator STA embeds full duplex transmission parameter settings in the PPDU (e.g., PPDU preamble) such as FD allowed indication, transmit power of the FD initiator STA, expected received power from the FD receiver STA, puncturing resource information of the PPDU, reserved channel resources for preemption at block 256.

Then, after the FD initiator transmits the preamble of the PPDU, it transmits 258 a known signal to cause the FD receiver STA to perform self-interference estimation during the known signal transmission time.

Then, at a check 260 in fig. 11, it is determined whether the FD originator STA detects a PPDU transmitted by the FD recipient STA.

If it detects a PPDU, the FD initiator starts receiving the PPDU from the FD receiver STA at block 262. The FD initiator STA continues its transmission whether or not it receives a PPDU from the FD receiver STA.

However, if a PPDU of the FD receiver STA is not detected at the check 260, the FD initiator STA continues its transmission at block 264.

5.1.2. FD transmission from the perspective of a receiver STA

Fig. 12 shows an example embodiment 270 of an FD recipient STA beginning a full duplex transmission initiated by an FD initiator STA.

The FD receiver STA receives 272 a PPDU. A check 274 determines whether full duplex transmission is allowed based on the PPDU. If not, then at block 282, the FD receiver STA does not transmit during the PPDU transmission of the FD initiator STA.

Otherwise, if FD transmission is allowed during the PPDU, the receiver STA starts 276 PPDU transmission to the FD initiator STA according to the full duplex transmission parameter settings in the PPDU received from the FD initiator STA. When the FD receiver STA starts transmitting PPDUs, it completes its self-interference estimation 278 during the time the FD initiator STA sends a known signal. The FD receiver STA may reserve 280 in its PPDU a portion of the channel resources that will not be transmitted in the time and/or frequency domain. The FD initiator STA may then detect a preemption request on the reserved channel resources. The reserved channel resources may be indicated in a PPDU transmitted by the FD initiator STA. In at least one embodiment/mode/option, the reserved channel resources are pre-negotiated.

5.2.1. Example 1 of full Duplex Transmission

Fig. 13 illustrates an example embodiment 290 of a full duplex transmission of PPDU 1. STA a292 is an FD initiator STA and STA C294 is an FD receiver STA. STA a accesses the channel and begins transmitting PPDU1 302 to STA C. Preamble 296 of PPDU1 indicates that full duplex transmission is allowed during PPDU1 time. STA a performs its self-interference check during the preamble time of PPDU 1.

STA C receives the preamble of PPDU1 from which it may recognize (know) that it is allowed to send PPDU2 304 with its preamble 298 to STA a for full duplex transmission. When STA a transmits the known signal 300 after it completes the preamble 296 of PPDU1, STA C may begin transmitting the preamble 298 of PPDU2 304 and perform its self-interference estimation during the known signal time of PPDU 1. Then, STA a and STA C exchange PPDU1 and PPDU2 at the same time.

The preamble of PPDU1 (e.g., the LTF field in the preamble) may be used by STA a for self-interference estimation, e.g., to determine what the self-interference is at the receiver after reflection from the environment. Meanwhile, a preamble of PPDU1 (e.g., an LTF field in the preamble) may be used by STA C for channel estimation from STA a.

STA C receives the preamble of PPDU1 and recognizes that FD is allowed. It may then start its PPDU2 transmission, such as immediately after the preamble of PPDU1 ends. The known signal after the preamble of PPDU1 is according to the following option. (1) In at least one option, the known signal may be composed of predefined signal(s), such as LTF fields. STA C may cancel the signal of the known signal of PPDU1 due to its channel estimation when receiving the preamble of PPDU 1. STA C may then perform its self-interference estimation when it is transmitting the preamble of PPDU 2. (2) In at least one other option, it is also possible that the known signal is orthogonal to the signal being transmitted by STA C, so that STA C does not need to cancel it. For example, the known signal is transmitted based on one row of the P matrix, and the preamble of PPDU2 uses another row of the same P matrix. The P matrix may be shared between STA a and STA C prior to full duplex transmission.

Both STA a and STA C may then cancel their self-interference and begin full duplex transmission. STA a starts transmitting the payload of PPDU1 and receives the payload of PPDU2.STA C starts transmitting the payload of PPDU2 and receives the payload of PPDU 1.

The duration of the known signal of PPDU1 should provide sufficient time for STA C to perform self-interference estimation for PPDU2. To do so, it is possible that the duration of the known signal of PPDU1 is the same as the duration of the preamble of PPDU2 or longer than the duration of the preamble of PPDU2. Alternatively, the preamble of PPDU2 should end at the same time as the known signal of PPDU1 or earlier than the known signal of PPDU 1.

Alignment of OFDM symbol boundaries between PPDU1 and PPDU2 may be necessary. In addition, STA a may set the level of transmission power of STA C in the preamble of PPDU 1.

It should be noted that it is possible that PPDU1 carries a Block Ack (BA) for a MAC Protocol Data Unit (MPDU) in PPDU2 and PPDU2 carries a BA for an MPDU in PPDU 1. An example is given in fig. 24 showing example 6 of preemption/interruption of FD transmission.

5.2.2. Example 2 of full Duplex Transmission

Fig. 14 illustrates another example embodiment 310 of a full duplex partial channel transmission. In contrast to the previous examples, the example herein describes STA a 292 requesting (claiming) STA C294 to leave an RU unused for transmission of PPDU2.STA a indicates this information in preamble 296 of PPDU1 302. When STA C receives this information, it transmits the preamble 298 but only uses a partial channel to transmit PPDU2 312, leaving RU 314 indicated by PPDU1 unused. The RU that is not used to transmit PPDU2 may thus be used by other STAs to send preemption requests, as will be explained later.

The preamble of PPDU1 (e.g., the LTF field of the preamble) may be used by STA a for self-interference cancellation estimation, such as STA a canceling a signal received from PPDU1 so that it may receive PPDU from another STA while transmitting PPDU 1. Meanwhile, a preamble of PPDU1, such as an LTF field in the preamble, may be used by STA C for channel estimation from STA a.

STA C receives the preamble 298 of PPDU1 and, based on the information therein, it recognizes that FD is allowed. STA C may then begin its PPDU2 312 transmission, such as immediately after the preamble of PPDU1 ends. Since there is a known signal 300 such as LTF after the preamble of PPDU1, STA C may cancel the signal of the known signal of PPDU1 due to its channel estimation when receiving the preamble of PPDU 1. STA C may then perform self-interference cancellation as needed when it is transmitting its preamble 298 of PPDU 2.

Thus, both STA a and STA C may cancel their self-interference and begin full duplex transmission. STA a starts transmitting the payload of PPDU1 and receives the payload of PPDU 2. STA C starts transmitting the payload of PPDU2 and receives the payload of PPDU 1.

It is possible that the duration of the known signal 300 of PPDU1 is the same as the duration of the preamble 298 of PPDU2 312. Alternatively, the preamble 298 of PPDU2 312 and the known signal 300 of PPDU1 should end at the same time. As shown, STA C does not use all RUs to transmit PPDU2; as may be indicated in the parameter settings for the full duplex transmission of PPDU 1. For example, STA a sets the RU indication field for FD to a first state (e.g., "0") in PPDU1, whereby the format of PPDU1 is as shown in fig. 29. In this case, another STA may transmit a preemption request to STA a through RU 314, which is not utilized by PPDU 2.

Alignment of OFDM symbols between PPDU1 and PPDU2 may be required to minimize inter-channel interference between PPDU1 and PPDU 2. In addition, STA a may set a transmit power level for STA C in the preamble of PPDU 1.

Preemption and/or interruption of fd transmissions

This section explains how the preempting STA sends preemption requests to preempted STAs to initiate preemption transmissions. The preempting STA indicates its preempting transmission priority in the preemption request. In at least one embodiment/mode/option, preempting a transmission is only allowed when the preempting transmission has a higher priority than the ongoing transmission.

As previously discussed, the preempted STA may transmit a PPDU with punctured resources. The preempting STA may sense a channel (or partial channel) during the punctured resource and send a preemption request on the channel (or partial channel) if there is no third party transmission.

If the preempted STA is performing FD transmission, it may request (ask) the FD receiver STA to leave at least one RU empty so that the preemption request may be transmitted by that RU.

The preempting STA may send a preemption request to reserve a short period of TXOP to occupy the channel and wait for a response from the preempted STA.

When the preempted STA receives a preemption request, it accepts or rejects the request. If it accepts the request, it interrupts its ongoing transmission. Otherwise, it continues its ongoing transmission.

If the preempted STA preempts the FD transmission of the preempted STA, the preempted STA is the FD initiator STA and it notifies its FD receiver STA to interrupt the transmission.

If the preempted STA accepts the preemption request, it may signal the acceptance of the preemption request by puncturing resources to inform the FD recipient STA to interrupt the ongoing FD transmission, thereby occupying the channel to avoid other preemption requests.

The preempting STA may begin preempting transmissions immediately after interrupting the ongoing transmission of the preempted transmissions. Alternatively, the preemption transmission may be triggered by the preempted STA.

It should be noted that the preempted STA may or may not be the intended receiver of the preempted transmission requested by the preempted STA. When the preempting STA sends a preemption request, it may or may not be the intended receiver of the preempted STA's ongoing PPDU transmission. In an example, the preempted STA is STA B and the preempted STA is STA a.

5.3.1. Interruption of ongoing FD transmission

Interruption of fd receiver STA

Fig. 15 shows an example embodiment 330 of an FD-initiator STA interrupting its ongoing full duplex transmission.

When the FD initiator STA decides 332 to interrupt its ongoing full duplex transmission, if it is receiving a PPDU from the FD receiver STA, it interrupts 334 the ongoing transmission of the FD receiver STA. For example, it may send a signal to the FD receiver STA to interrupt the ongoing transmission. It should be noted that it is possible that if the FD receiver STA does not interrupt its ongoing transmission according to the previous interrupt signal, the FD initiator STA sends another interrupt signal to the FD receiver STA.

The FD initiator STA then interrupts 336 its own ongoing PPDU transmission. The FD initiator may perform this as follows. (a) it may interrupt its ongoing PPDU transmission at any time. A DTX acknowledgement signal may be sent to indicate an interruption of the ongoing PPDU. (b) It may interrupt its ongoing PPDU at the end of one MPDU of the PPDU. (c) It may complete its current PPDU transmission and then refrain from initiating another PPDU transmission within the current TXOP.

5.3.1.2.FD recipients interrupt ongoing FD transmissions

Fig. 16 shows an example embodiment 350 in which the FD recipient STA interrupts its own ongoing full duplex transmission.

When the FD receiver STA receives 352 a signal from the FD initiator STA to interrupt the ongoing transmission, the FD receiver STA interrupts 354 its ongoing PPDU transmission.

5.3.1.3. Preempting STA preempting PPDU

Fig. 17 illustrates an example embodiment 370 of a preempting STA initiating a preemption transmission.

The preempting STA sends 372 a signal to the preempted STA requesting preemption transmission. A check 374 determines whether the preempting STA receives a signal from the preempted STA to begin preempting transmissions. If the condition is met, it begins preempting transmissions at block 376. Otherwise, execution reaches block 378 and preemptive transfer is not allowed.

In at least one embodiment/mode/option, even if the preempting STA senses channel idleness on the punctured resources of the preempted STA's PPDU transmission, the preempting STA does not send a preemption request if the Relative Signal Strength Indication (RSSI) at the preempting STA is above a given threshold.

If the preempted STA is an FD initiator STA and performs full duplex transmission, the preempted STA may only sense the puncturing resources on RUs that are not used for transmission by the FD receiver STA.

5.3.1.4. Preemption of PPDUs at preempted STAs

Fig. 18 illustrates an example embodiment 390 of a preempted STA accepting or rejecting preempted transmissions.

The preempted STA receives 392 a signal from the preempted STA requesting preemption of the transmission. The preempted STA makes decision 394 to accept or reject the preemptive transfer request. For example, if the preempting transmission is higher priority than the preempted STA's ongoing transmission, it may accept the request and execution moves to block 396; otherwise, it denies the request and execution moves to block 400.

If the preempted STA accepts the preemption transmission request, it interrupts 396 its ongoing transmission. The procedure of interruption of PPDU transmission may be the same as shown in fig. 15 and 16. The preempted STA then sends 398 a signal to the preempted STA to begin the preempt transmission.

If the preempted STA refuses to preempt the transmission request at check 394, the preempted STA continues 400 its ongoing transmission.

5.4. Preempting backoff procedures for STAs

When the preempting STA is to preempt an ongoing transmission, it may perform (run) a backoff procedure to obtain (get) channel access. The preempting STA only senses channel conditions during the backoff procedure during the puncturing of resources as indicated by the ongoing PPDU transmitted by the preempting STA. The back-off counter is decremented (e.g., decremented by one) if the channel condition during the punctured resource is idle for the back-off slot time. Otherwise, the backoff counter is not decremented. When the backoff counter reaches zero and the channel is still idle, the preempting STA gains channel access.

If the preempted STA is performing FD transmission, the preempted STA senses channel conditions during puncturing of resources only on a portion of the channel (RU) that is not used by the FD receiver STA for the FD transmission.

The backoff procedure used for preemption may be either independent of or part of conventional EDCA as described below. (a) The backoff procedure used for preemption may be independent of the backoff procedure used for conventional EDCA (or CSMA/CA) channel contention. The backoff procedure for preemption is only used when the preempting STA contends for the channel for the preemption transmission. When the preempting STA does not contend for the channel to perform the preemption transmission, then the backoff counter used for preemption may be either reset or suspended. (b) The preempting STA may allow EDCAF of some Traffic Identifier (TID) to contend for the channel to perform preemption. These EDCAF may start or continue in their channel contention when the preempting STA decides to initiate preemption transmissions for those TIDs.

5.4.1. Examples of preemption/interrupt

5.4.1.1. Example 1 preemption/interrupt

Fig. 19 illustrates an example embodiment 410 of preempting and/or interrupting FD transmissions when a preempted STA is transmitting only. This example shows an example where preempting STA B414 sends a preemption request signal and begins its preemption transmission immediately after it detects an interruption in the preempted STA a's PPDU transmission.

STA a 412 is a preempted STA and is shown to transmit a preamble 416 of PPDU1 418, which includes a priority indication set herein for lower priorities. PPDU1 is embedded with puncturing resources 420.STA B414 is a preempting STA that contends for the channel by sensing the channel state during the puncturing resources of PPDU 1. For example, STA B counts down the backoff 422 when it senses that the channel is idle during the puncturing resources of PPDU1 and pauses the backoff when it senses that the channel is busy during the puncturing resources of PPDU 1. Also, STA B may suspend backoff 422 when STA a is transmitting PPDU1 with a higher priority than PPDU 2. When backoff 422 is counted down to zero, then STA B may access the channel and send a signal 424 to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown, STA B sends a preemption request signal 424 to STA a. In at least one embodiment/mode/option, the preemption preamble 428 indicates the priority of the preemption transmission (p=high in the figure) depicted by PPDU2 430, as well as other parameters such as the length of the preemption transmission.

When STA a receives the preemption request signal 424, it decides whether to accept the preemption request. In this example case, STA a accepts the request and immediately interrupts and ceases its ongoing PPDU1 418 transmission, as seen by Discontinuous Transmission (DTX) 426. It will be noted that DTX portion 426 of PPDU1 is the portion of PPDU1 that was not transmitted due to the interruption.

If STA a immediately interrupts its ongoing transmission (e.g., during the IFS time), STA B may begin a preempting transmission as illustrated by PPDU2 430. STA B recognizes the interruption of PPDU1 by sensing that the channel is idle for a small period of time (e.g., SIFS time), and thus STA B transmits a preamble 428 (which in this example includes a high priority indicator) and PPDU2 430, which may itself have puncturing resources.

In some embodiments/modes/options, the gap between the end time of the preemption request signal and the start time of the preamble of PPDU2 should not be longer than a selected period of time, such as, for example, an ACK/BA timeout, or two SIFS periods. Alternatively, if STA B has FD capability, it may continue transmitting or keep the channel busy until it detects that STA a interrupts PPDU1 transmission. For example, STA B sends a padding after the preemption request signal to continue (keep) transmitting or otherwise keep the channel busy.

5.4.1.2. Example 2 preemption/interrupt

Fig. 20 illustrates an example embodiment 450 of preempting and/or interrupting FD transmissions when a preempted STA is transmitting only. This example demonstrates that when preempted STA a receives a preemption request from preempted STA B, it sends a DTX signal to indicate an interruption in its ongoing PPDU transmission. The preempting STA then recognizes the interruption of the preempted STA's PPDU transmission and begins its preempted transmission.

STA a 412 is a preempted STA and is transmitting PPDU1 418 with embedded puncturing resources 420, preceded by a preamble 416.STA B414 is a preempting STA that may contend for the channel by sensing the channel state during the punctured resources of PPDU 1. For example, STA B counts down backoff 422 when it senses that the channel is idle during puncturing resource 420 of PPDU1 and pauses backoff when it senses that the channel is busy. In at least one embodiment/mode/option, STA B pauses its backoff when STA a is transmitting PPDU1 with a higher priority than PPDU 2. When the backoff is counted down to zero, STA B may access the channel and send a signal to request preemption of the transmission.

It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown, STA B sends a preemption request signal 424 to STA a. The preemption request signal may indicate a priority (P) =high in the figure) of the preemption transmission (e.g., PPDU2 430). Preemption request 424 may also reserve a period of TXOP, such as a period of length l_length 452, to prevent other STAs from accessing channels in the figure while waiting for DTX acknowledgement. When STA a receives the preemption request signal, it is shown ending its PPDU1 transmission and accepting the preemption request with DTX acknowledgement signal 454. DTX portion 456 of PPDU1 is the portion of PPDU1 that was not transmitted due to the interruption. From the information in DTX acknowledgement signal 454, both the receiver of PPDU1 and STA B may recognize (know) that PPDU1 has been interrupted.

If STA a interrupts its ongoing transmission for L length of time, STA B may begin its preemptive transmission, depicted here as PPDU2430 with its preamble 428. It will be appreciated that STA B may optionally include one or more puncturing resources 432 in PPDU 2.

STA a may decide when to allow interruption of its ongoing PPDU, PPDU1, for l_length time. If the value of L_Length time is set to a particular flag value, such as 0, it may indicate that STA A may interrupt its ongoing PPDU, namely PPDU1, at any time.

5.4.1.3. Example 3 preemption/interrupt

Fig. 21 illustrates an example embodiment 470 of preempting and/or interrupting FD transmissions when the preempted STA is transmitting only. Preempting STA B sends a preemption request signal to initiate preemption transmissions. The preemption request also reserves a small TXOP time so that other STAs will not access the channel until the expected time that STA a triggers preemption transmission. Preempted STA a interrupts its ongoing transmission and triggers a preempting transmission.

STA a 412 is a preempted STA and is transmitting PPDU1 418 preceded by a preamble 416, the preamble 416 containing an indication that the PPDU is low priority. PPDU1 is embedded with puncturing resources 420.STA B414 is a preempting STA. STA B contends for a channel by sensing a channel state during the punctured resources of PPDU 1. For example, STA B counts down backoff 422 when it senses that the channel is idle during puncturing resource 420 of PPDU1, otherwise pauses backoff when it senses that the channel is busy. In at least one embodiment/mode/option, STA B pauses its backoff when STA a is transmitting PPDU1 with a higher priority than PPDU 2.

When backoff 422 is counted down to zero, STA B may access the channel and send a signal 472 to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown in the example, STA B transmits the preemption request signal 472 to STA a over the entire channel. The preemption request signal may include an indication of the priority of the preemption transmission (e.g., PPDU2 486). The preemption request signal may reserve a period of TXOP, such as shown by l_length 474 in the figure, to prevent other stations from interfering while it waits for a response regarding its preemption request.

When STA a receives the preemption request signal, it decides to accept the request and suspend transmission of PPDU1 418, and it sends a DTX acknowledgement signal 476. DTX portion 480 of PPDU1 is the portion of PPDU1 that was not transmitted due to the interruption. It will be noted that it is STA a that decides when to interrupt its ongoing PPDU, PPDU1, for l_length time.

As shown, l_length 474 may be set to the time that STA B expects to receive SU trigger frame 478 from STA a or the expected time that CTS frame 482 will be sent.

If STA a interrupts its ongoing transmission and sends a frame (e.g., SU trigger frame 478) to initiate a preemptive transmission within l_length time, STA B may begin its preemptive transmission, e.g., PPDU2 486 preceded by preamble 484, which preamble 484 in this case indicates its priority as higher than PPDU1. The format of the SU trigger may be the same as MU-RTS TXS trigger frame 482 as defined in IEEE 802.11 be. Then, upon receiving SU trigger 478, STA B sends CTS frame 482 back to STA a and begins its own preemptive transmission depicted as preamble 484 and PPDU2 486; PPDU2 486 itself may have one or more puncturing resources 488. In at least one embodiment/mode/option, the SU trigger frame only allows a given duration during which PPDU2 transmissions must be completed, or it allows the CTS to extend beyond the NAV of the SU trigger. In at least one embodiment/mode/option, STA B does not send a CTS frame, but rather begins transmitting PPDU2 immediately after receiving a SU trigger frame from STA a.

It should be noted that having puncturing resources in PPDU2 is optional.

5.4.1.4. Example 4 preemption/interrupt

Fig. 22 illustrates an example embodiment 510 of preempting and/or interrupting FD transmissions when a preempted STA is transmitting only. In contrast to the previous example, the preempting STA sends an RTS frame to request preemption and reserve TXOP time for preempting transmissions, otherwise the station and initial operation are the same.

STA a 412 is a preempted STA and is transmitting PPDU1 418 with its preamble 416, which preamble 416 contains information that PPDU1 is low priority (lower than PPDU2 in this example). PPDU1 is seen to have embedded puncturing resources 420.STA B414 is a preempting STA that may contend for the channel by sensing the channel state during the punctured resources of PPDU 1. For example, STA B counts down the backoff 422 when it senses that the channel is idle during the puncturing resource of PPDU1 and pauses its backoff when it senses that the channel is busy. In at least one embodiment/mode/option, STA B pauses backoff when STA a is transmitting PPDU1 with a higher priority than PPDU 2.

When the backoff is counted down to zero, STA B may access the channel and send a signal 512 to request preemption of the transmission. It will be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a. As shown, the signal sent by STA B to request a preemption transmission is an RTS frame (denoted as preemption RTS frame) because the preemption request signal is sent to STA a over the entire channel. The preemption RTS frame may indicate the priority of a preemption transmission, such as PPDU 2. The preemptive RTS frame may also reserve a TXOP or set a NAV 514 for the preemptive transmission.

When STA a receives the preemptive RTS frame, it decides whether it will accept the request. The preempted STA (illustrated as STA a) is expected to make a decision as to when it will interrupt its ongoing PPDU (shown as PPDU 1).

In this example, STA a accepts the preemption request and immediately interrupts PPDU1 transmission. The DTX portion 520 of PPDU1 is the portion of PPDU1 that was not transmitted due to the interruption. STA a then transmits a DTX acknowledgement signal 516 indicating an interruption in its ongoing transmission. STA a then transmits a frame 518 (shown as a trigger frame, shown by way of example and not limitation as a Single User (SU) trigger frame) to initiate the preemptive transmission. The format of the SU trigger may be the same as the MU-RTS TXS trigger frame as defined in IEEE 802.11 be. STA B then sends a CTS frame 522 back to STA a and begins its preemptive transmission depicted as preamble 524 and PPDU2 526. The preamble 524 in this example contains priority information, such as the priority of PPDU2 over the priority of PPDU 1. PPDU2 may also contain one or more puncturing resources 528.

In contrast to the methods in the previous examples, the RTS may set its NAV 514 for preemptive transmissions (e.g., PPDU2 transmissions as shown). If the preemption transmission did not start successfully (e.g., STA a did not interrupt its PPDU1 transmission, or STA B did not send a CTS frame), any third party STA may cancel the NAV set by the RTS frame. The RTS frame may also add a packet extension field or padding signal at the time it expects to receive the SU trigger frame.

5.4.1.5. Example 5 preemption/interrupt

Fig. 23 illustrates an example embodiment 550 of preempting and/or interrupting FD transmissions when a preempted STA is transmitting only. This example has included a third station in the communication example and the preempted STA uses the punctured resources of its ongoing PPDU transmission to indicate the outcome of the preemption request and to occupy the channel so that other STAs will not send another preemption request. Also, the preempted STA a may repeat symbols that may be interfered by the preemption request in the Packet Extension (PE) of PPDU 1.

STA a 554 is a preempted STA and is transmitting PPDU1 560 with its preamble 558 to STA C552. PPDU1 is embedded with puncturing resources 562.STA B556 is a preempting STA that may contend for the channel by sensing the channel state during the punctured resources of PPDU 1. For example, STA B counts down the backoff 564 when sensing that the channel is idle during the puncturing resource of PPDU1 and pauses the backoff when sensing that the channel is busy. In at least one embodiment/mode/option, STA B pauses backoff when STA a is transmitting PPDU1 with a higher priority than PPDU 2. When the backoff is counted down to zero, STA B may access the channel and send a signal 566 to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown, STA B sends a preemption request signal 566 to STA a. The preemption request signal may also indicate a priority of preemption transmissions depicted as PPDU2 582.

When STA a receives the preemption request signal 566, it decides whether to accept the request. In this example, STA a accepts the request. In at least one embodiment/mode/option, STA a begins transmitting signals and/or noise during puncturing resources (puncturing resource transmission) 568 in PPDU 1. STA B and other STAs, such as STA C, may then sense CCA busy during the puncturing resources of PPDU 1. At the same time, they may recognize that a third party transmission is in progress or planned.

In at least one embodiment/mode/option, STA a sends an acknowledgement (Ack) to STA B over puncturing resource 563 of PPDU1 indicating that the preemption request was accepted or rejected by STA a, which may also be used to prevent other STAs from sending requests and informing STA C of preemption.

STA a may decide to initiate a preemption transmission after completing its ongoing PPDU (i.e., PPDU1 560). At the end of PPDU1, STA a may add a Packet Extension (PE) 570. The NAV period 572 begins at the beginning of the PE period. The PE may repeat symbols that may be interfered by STA B (i.e., symbols of PPDU1 transmitted during the transmission time of the preemption request signal of STA B). STA C may also send a BA 574 to STA a during this PE time 570.

It should be noted that repeated symbols may have to occur prior to BA transmission. STA a then stops its transmission and sends a signal 576 to initiate a preemptive transmission by STA B. By way of example, this signal is represented here as a SU trigger frame to STA B, which may be the same format as a MU-RTS TXS trigger frame as defined in IEEE 802.11 be. It should be noted that PPDU2 may also have one or more puncturing resources 584. In at least one embodiment/mode/option, the SU trigger is only allowed to trigger the preemption transmission of STA B within the NAV time obtained by STA a.

5.4.1.6. Example 6 preemption/interrupt

Fig. 24 illustrates an example embodiment 590 of preempting and/or interrupting FD transmissions when a preempted STA is performing FD transmissions. In this example, the preempting STA B transmits a preemption request signal with padding through the preemption signaling RU to reserve a TXOP for a short period. STA a responds to the preemption request within the TXOP time reserved by the preemption request. If STA B recognizes that its preemption request is accepted, it sends another preamble or Null Data Packet (NDP) to occupy the preemption signaling RU to prevent other STAs from sending preemption request signals until the start of the preemption transmission.

STA a 554 is the preempted STA and is seen to transmit preamble 558, followed by known signal 594, then PPDU1 596 with puncturing resource 598; and receives PPDU2 602 with preamble 592 from STA C552. PPDU2 is transmitted through some RUs of the channel while leaving one or more RUs 604 for preemption signaling.

STA B556 is a preempting STA that contends for the channel by sensing the channel state during the punctured resources of PPDU1, which is shown as sensing CCA busy at some times 600 and not sensing CCA busy 598 at other times. For example, STA B counts back-off 606 down when channel idle 598 is sensed on the punctured resources of PPDU1 located on the preemption signaling RU, and it pauses back-off when channel busy 600 is sensed. When the backoff 606 is counted down to zero, STA B may access the channel and send a signal 608 to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown, STA B transmits a preamble 1 608 to STA a, followed by a preemption request signal 610 and padding 612. By way of example, preamble 1 may include a legacy preamble, e.g., a non-HT, HT, VHT, HE, EHT preamble, as defined in IEEE 802.11 be. The preemption request signal is transmitted through a preemption signaling RU that is not used to transmit PPDU 2. The preemption request signal may include an indication of the priority of the preemption transmission (e.g., PPDU3 632). Due to the preemption signal and padding on the preemption signaling RU, other nodes will sense the punctured resources and will not send signals that may interfere.

When STA a receives the preemption request signal, it decides whether to accept the request. In this example, STA a accepts the request. In at least one embodiment/mode/option, STA a begins transmitting signal 614 during the puncturing resources in PPDU1 as the puncturing resources transmit signal. When STA a transmits a signal during the puncturing resources of PPDU1, it may signal STA B to indicate acceptance of the preemption request. For example, STA a may also send Ack signal 615 over the puncturing resources to inform STA B that its preemption request was accepted. The Ack may be transmitted by a PSK/QAM signal containing encoded information with a Cyclic Redundancy Check (CRC) and may be equalized (using the LTF of STA a) and decoded for CRC check. The CRC check distinguishes the Ack from third party interference. The format of the Ack may be the same as defined in IEEE 802.11, containing the MAC address of STA B, which may then send another preamble 2 616 with padding 618 to occupy the channel until the start of the preemption transmission. Due to padding on the preemption signaling RU, other nodes will sense the punctured resources at the preemption signaling RU on the punctured resources and not transmit signaling.

At the end of PPDU1 and PPDU2, STA a and STA C may exchange BAs 620 and 626 to report packet loss of portions of PPDU1 and PPDU2 that have been transmitted. It will be noted that the NAV begins 622 at this time. STA a then does not begin transmitting another PPDU, but instead sends a signal 626 to initiate a preemptive transmission by STA B. By way of example and not limitation, the signal illustrated herein is a SU trigger frame as sent from STA a to STA B herein, which may be the same format as the MU-RTS TXS trigger frame as defined in IEEE 802.11 be.

STA B then responds 628 (illustrated as a CTS frame) to STA a and begins a preemptive transmission, with the preamble 630 and PPDU2 632 shown being transmitted. It should be noted that PPDU2 and/or PPDU3 may have one or more puncturing resources 634.

In at least one embodiment/mode/option, the SU trigger is only allowed to trigger the preemption transmission of STA B within the NAV time obtained by STA a.

It should be noted that preamble 1 608 of STA B may be allowed only to reserve a limited TXOP time, set a limited NAV, or remain a limited CCA busy or fill time. For example, in at least one embodiment/mode/option, those times should not exceed the expected reception time of the Ack from STA a.

5.4.1.7. Example 7 preemption/interrupt

Fig. 25 illustrates an example embodiment 650 of preempting and/or interrupting FD transmissions while the preempted STA is performing FD transmissions. In contrast to the previous example, the figure shows that preamble 1 and preamble 2 may reserve a portion of the TXOP instead of transmitting a padding signal. STA a is a preempted STA and is transmitting PPDU1 to STA C and receiving PPDU2 from STA C. PPDU1 embeds puncturing resources. PPDU2 is not transmitted on an RU (i.e., a preemption signaling RU as shown).

By way of example and not limitation, three stations are again shown interacting in the figure: STA C552, STA a 554, and STA B556. The first part of the figure is identical to that of figure 24 up to the point below.

STA B556 is a preempting STA that may contend for the channel by sensing the channel state during the punctured resources of PPDU 1. For example, STA B counts back-off 606 down when channel idle 598 is sensed on the punctured resources of PPDU1 located on the preemption signaling RU and pauses back-off when channel busy 600 is sensed. When the backoff 606 is counted down to zero, STA B may access the channel and send a signal to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with STA a.

As shown, STA B transmits a preamble 1 608 to STA a, followed by a preemption request signal 656. Preamble 1 may be the same as a legacy preamble (such as a non-HT, HT, VHT, HE, EHT preamble) as defined in IEEE 802.11be, but is not limited thereto. The preemption request signal is transmitted through a preemption signaling RU that is not used to transmit PPDU 2. The preemption request signal may include an indication of the priority of the preemption transmission (which is depicted as PPDU 3). The preemption request reserves a TXOP time with l_length1 652 to wait for an Ack 655 from the puncture resource transmit signal 654 from STA a.

When STA a receives the preemption request signal, it decides whether to accept the request. It is possible that STA a starts transmitting a signal and/or noise during a puncturing resource (puncturing resource transmitting signal) in PPDU 1.

Other STAs may then sense that the channel is busy and not accessing the channel during those punctured resources. When STA a transmits a signal during the preemption resources of PPDU1, it may signal STA B to indicate acceptance of the preemption request. For example, STA a is illustrated herein as sending an Ack 655 signal over the puncture resource to inform STA B that its preemption request was accepted. The Ack may be transmitted by a PSK/QAM signal containing encoded information with a CRC and may be equalized (using the LTF of STA a) and decoded for CRC check. The CRC check distinguishes the Ack from third party interference. The format of the Ack may be the same as defined in IEEE 802.11, which contains the MAC address of STA B. STA B may then send another preamble 2 658 to reserve the TXOP for l_length2 660 until the start of the preemptive transmission.

At the end of PPDU1 and PPDU2, STA a and STA C may exchange BAs 662 and 666 to report packet loss for those portions of PPDU1 and PPDU2 that have been transmitted. NAV 664 is shown to begin at the beginning of these BAs. STA a then stops transmitting another PPDU and sends a signal 668 to initiate a preemptive transmission by STA B. By way of example, STA a transmits a SU trigger frame 668 to STA B, which may be the same format as the MU-RTS TXS trigger frame as defined in IEEE 802.11 be. In response, STA B sends a CTS frame 670 back to STA a and begins a preemptive transmission depicted with a preamble 672 and PPDU3 674.

It should be noted that both PPDU2 and PPDU3 may also include puncturing resources. In at least one embodiment/mode/option, if PPDU3 is transmitted to STA a, PPDU3 may be used to initiate full duplex transmission between STA a and STA B; in this case, the format of PPDU3 should be the same as PPDU 1.

It should be noted that l_length1 652 should cover the time span of at least one puncturing resource of PPDU1 so that STA a can use the puncturing resource to transmit an Ack for the preemption request frame. L_length1 should not exceed the end time of PPDU1 (possibly including BA time).

It is possible that the SU trigger is only allowed to trigger the preemption transmission of STA B within the NAV time obtained by STA a.

5.4.1.8. Example 8 preemption/interrupt

Fig. 26 illustrates an example embodiment 690 of preempting and/or interrupting FD transmissions while a preempted STA is performing FD transmissions. In contrast to the previous example, this example illustrates STA B transmitting only one preemption request signal to reserve the period of the TXOP to wait for the start of a preemption transmission (PPDU 3).

The beginning of the figure is the same as described in the previous figures, as mentioned by similar reference numerals. STA a 554 is a preempted STA and is transmitting PPDU1 596 to STA C552 and is receiving PPDU2 from STA C. PPDU1 is embedded in puncturing resource 598.

PPDU2 602 is not transmitted through one or more RUs 604 that are used for preemption signaling. STA B556 is the preempting STA. STA B may contend for the channel by sensing the channel state during the puncturing resource 598 of PPDU1 596. For example, STA B counts back-off 606 down when channel idle is sensed on the punctured resources of PPDU1 located on the preemption signaling RU and pauses back-off when channel busy is sensed. When the backoff is counted down to zero, STA B may access the channel and send an optional signal 694 to request preemption of the transmission. It should be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

As shown, STA B sends a preemption request signal 696 to STA a. The preamble of the preemption request may be the same as a legacy preamble, such as a non-HT, HT, VHT, HE, EHT preamble, as defined in IEEE 802.11be, but is not limited thereto, and may be transmitted through the entire channel. The preemption request signal is transmitted through the preemption signaling RU. The preemption request signal may include an indication of the priority of the preemption transmission exemplified as PPDU3 710. The preamble 694 of the preemption request may also reserve a TXOP period (such as L length time 692) or set a NAV.

When STA a receives the preemption request signal, it determines whether to accept the request. In this example, STA a accepts the request and interrupts its ongoing transmission for l_length time 692 and sends a DTX acknowledgement signal 698. In view of the transmission of DTX acknowledgement signal 698, the receiver of PPDU1 (e.g., STA a) recognizes the interruption of PPDU1 and STA C552 at the same time interrupts its own ongoing transmission of PPDU2 602.

Upon accepting the preemption request, STA a decides when to interrupt its ongoing PPDU, PPDU1 596. For example, STA a may decide to interrupt the PPDU upon completion of the current MPDU transmission.

STA a is shown interrupting its ongoing transmission and transmitting a signal 702 illustrated as a SU trigger frame for L length time 692; this allows STA B to initiate its preemption transmission depicted as PPDU3 710.

Therefore, in this case, STA a has finished PPDU1 596 transmission by sending DTX acknowledgement signal 698. Based on the DTX acknowledgement signal, both the receiver of PPDU1 and STA B may recognize the interruption of PPDU 1. It will be noted that DTX portion 704 of PPDU1 and DTX portion 700 of PPDU2 are portions of PPDU1 and PPDU2 that were not transmitted due to the interruption. Upon receiving the signal 702 (e.g., SU trigger), STA B responds with a CTS 706, which CTS 706 may be set to extend the NAV set by the SU trigger. Thereafter, STA B transmits a preamble 708 optionally containing priority information followed by its PPDU depicted as PPDU3 710, which may include one or more puncturing resources 712.

It should also be noted that PPDU2 and PPDU3 may have optional one or more puncturing resources. In at least one embodiment/mode/option, if PPDU3 is transmitted to STA a, PPDU3 may be used to initiate full duplex transmission between STA a and STA B; in this case, the format of PPDU3 should be the same as PPDU 1.

5.4.1.9. Example 9 preemption/interrupt

Fig. 27 illustrates an example embodiment 730 of preempting and/or interrupting FD transmissions while the preempted STA is performing FD transmissions. In contrast to the previous examples, the figure shows that the preemption request signal can be transmitted using RU preemption signaling only. The first part of the figure is the same as that described in fig. 26.

STA a 554 is a preempted STA and is transmitting a PPDU1596 to STA C552 preceded by a preamble 558 and a known signal 594; and STA a is receiving PPDU2602 from STA C552. PPDU1 has embedded puncturing resources 598.PPDU2602 is not transmitted on all RUs because RU 604 is shown reserved for preemption signaling.

STA B556 is a preempting STA that may contend for the channel by sensing the channel state during the puncturing resources 598 of PPDU1 596. For example, STA B counts back-off 606 down when it senses that the channel is idle on the punctured resource 598 of PPDU1596 located on the preemption signaling RU and pauses back-off when it senses that the channel is busy. When the backoff is counted down to zero, STA B may access the channel and send a signal 734 to request preemption of the transmission. It will be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

In this example, the preamble of the preemption request and the preemption request signal are transmitted on the preemption signaling RU 734. The preemption request signal may include a priority indicator for the preemption transmission (e.g., for PPDU 3748). The preamble of the preemption request may also reserve a TXOP period, such as l_length 732.

When STA a receives the preemption request signal, STA a decides whether to accept it. In this example, STA a is considered to accept the request and STA a interrupts its ongoing transmission 596 for l_length time 732 and ends its PPDU1 transmission by sending a DTX acknowledgement signal 736.

In view of the use of the DTX acknowledgement signal, STA C, which is the receiver of PPDU1, recognizes the interruption of PPDU1 and interrupts its own ongoing transmission of PPDU2 602 at the same time. It will be noted that DTX portion 742 of PPDU1 and DTX portion 738 of PPDU2 are portions of PPDU1 and PPDU2 that were not transmitted due to the interruption.

STA a may decide when to interrupt its own ongoing PPDU, PPDU1596. For example, STA a may decide to interrupt the PPDU upon completion of the current MPDU transmission. If STA a interrupts its ongoing transmission and transmits a signal such as SU trigger frame 740 for L length time 732, this allows STA B to initiate its preemptive transmission.

The figure shows that STA B sends a CTS 744, which CTS 744 may also extend the NAV set by the SU trigger. Thereafter, STA B transmits a preamble 746 (which may include priority information), followed by PPDU3 748, which may include its own one or more puncturing resources 750.

It should be noted that any PPDU may contain puncturing resources. In at least one embodiment/mode/option, PPDU3 may be used to initiate full duplex transmission between STA a and STA B if PPDU3 is transmitted to STA a. Then the format of PPDU3 should be the same as PPDU 1.

5.4.1.10. Example 10 preemption/interrupt

Fig. 28 illustrates an example embodiment 770 of preempting and/or interrupting FD transmissions when a preempted STA is performing FD transmissions. In contrast to example 8, this example shows that the preempting STA uses the punctured resources to send an acknowledgement (Ack) for the preemption request and a DTX acknowledgement signal to interrupt full duplex transmission. After STA a interrupts its FD transmission, STA B starts transmitting PPDU3 immediately after PPDU1 is interrupted. L_length is independent of PPDU3 length.

The first part of the figure is the same as seen in the previous figures. STA a 554 is a preempted STA and is transmitting PPDU1 596 to STA C552; and PPDU2 602 is being received from STA C. PPDU1 596 contains embedded puncturing resources 598.PPDU2 is not transmitted on all RUs because at least one RU is reserved for preemption signaling 604 as shown.

STA B556 is a preempting STA and may contend for the channel by sensing the channel state during the puncturing resource 598 of PPDU1 596. For example, STA B counts back-off 606 down when it senses that the channel is idle on the puncturing resource 598 of PPDU1 located on the preemption signaling RU and pauses back-off when it senses that the channel is busy. STA B may access the channel and send a signal to request preemption of the transmission. This signal is shown as a preemption request signal 776 transmitted on a preemption signaling RU 777 and may include a priority value for the preemption transmission (e.g., PPDU3 786). The optional preamble 774 may be transmitted prior to the signal 776. The preamble of the preemption request may be a legacy preamble, such as a HT, VHT, EHT preamble, as defined in IEEE 802.11be, but is not limited thereto, and is transmitted over the entire channel in this case.

It will be noted that when STA B accesses the channel, it may wait for a few microseconds to align its OFDM symbol boundaries with those of STA a.

When STA a receives the preemption request signal, it decides whether to accept the request. In this example, STA 1 accepts the preemptive transfer request, interrupts its ongoing transmission for l_length time 772, and sends a DTX acknowledgement signal 778 and optionally an Ack 779 over the puncturing resources. STA a may decide when to interrupt its ongoing PPDU, PPDU1.STA a may send an Ack signal over the punctured resources to inform STA B that its preemption request was accepted. The Ack may be transmitted, for example, by a PSK/QAM signal containing encoded information, such as with a CRC, and may be equalized (using the LTF of STA a) and decoded for CRC check. The CRC check allows to distinguish the Ack from the third party interference. The format of the Ack may be the same as that defined in IEEE 802.11, but is not limited thereto, and it contains the MAC address of STA B.

In response to receiving the DTX acknowledgement signal, both the receiver of PPDU1 (which is STA C) and the preempting STA of STA B may recognize that the ongoing transmission of PPDU1 596 has been interrupted and that the ongoing transmission of PPDU2 602 has been interrupted. It should be noted that DTX portion 782 of PPDU1 and DTX portion 780 of PPDU2 are portions of PPDU1 and PPDU2 that were not transmitted due to the interruption.

STA B may begin its preemptive transmission immediately after PPDU1 interruption without the need for a CTS and it transmits PPDU3 786, preceded by a preamble 784 that may include priority information.

It should be noted that the puncturing resources may alternatively be included in PPDU2 and/or PPDU 3. In at least one embodiment/mode/option, if PPDU3 is transmitted to STA a, PPDU3 may be used to initiate full duplex transmission between STA a and STA B; in this case, the format of PPDU3 should be the same as PPDU 1.

6. Data format

The following data formats are shown by way of example and not limitation. It should be noted that some of these fields may utilize the previously defined formats, although they are not limited to those formats.

Fd PPDU format

Fig. 29 illustrates an example embodiment 810 of a PPDU format that may be used for FD transmission and preemption. The FD PPDU format may be used when the FD initiator or FD receiver or preempting STA or preempted STA starts transmitting PPDUs.

The field between the L-STF and the EHT-LTF is the preamble of the PPDU. The fields L-STF, L-LTF, L-SIG, RL-SIG, EHT-STF, and EHT-LTF may be the same as defined in IEEE 802.11be, but are not limited thereto. The fields U-SIG and EHT-SIG may be the same as defined in IEEE 802.11be, with the following additional fields.

The FD transmission permission field is set to a first state (e.g., "1") to indicate that a PPDU is transmitted for FD transmission. The receiver STA can thus recognize that there is an ongoing FD transmission and that the transmitter STA of this PPDU is either the FD initiator or the receiver. Otherwise, the field is set to a second state (e.g., "0").

The FD initiator/receiver field is set to indicate whether the sender of the PPDU is an FD initiator or an FD receiver. When the FD transmission enable field is set to a second state (e.g., "0"), the field may be reserved. It is possible that if the transmitter STA is an FD initiator and preemption is allowed, STAs that are not FD initiators or receivers may request preemption transmissions during the PPDU transmission time.

The time and frequency fields of the puncturing resources are used to indicate the length, periodicity, and frequency allocation of one or more puncturing resources in the PPDU. From this field, the receiver STA may obtain information of the punctured resources in the PPDU and sense the channel on the punctured resources to detect any third party transmissions.

The preemption allow field is set to a first state (e.g., "1") to indicate that preemption is allowed. The receiver STA may request preemption during the PPDU transmission time. In at least one embodiment/mode/option, the receiver STA requests preemption of transmissions when its PPDU is higher priority than the PPDU. Otherwise, it is set to a second state (e.g., "0") and the receiver STA is not allowed to request preemption during the PPDU transmission time. In at least one embodiment/mode/option, if the transmitter STA is an FD receiver, this field must be set to a second state (e.g., "0"). In at least one embodiment/mode/option, when the FD PPDU is transmitted during a spatial reuse transmission or a coordinated MAP transmission by the transmitter STA, the transmitter STA sets this field to a second state (e.g., "0") in the FD PPDU. In at least one embodiment/mode/option, the transmitter STA is not allowed to transmit FD PPDUs during its spatial reuse transmission or coordinated MAP transmission.

The priority field indicates the priority of the PPDU. This field may be UP, AC, TID or any other information that may indicate the priority of the PPDU.

The RU indication field as the FD is set to indicate the presence of the common information field and the user information list field. If it is set to a first state (e.g., "1"), a common information field and a user information list field exist. Otherwise, if it is set to the second state (e.g., "0"), the common information field and the user information list field do not exist.

The common information (Info) field may be the same as the common information field in the basic trigger frame as defined in IEEE 802.11 ax. Receiver STAs, which are FD receivers or preempting STAs, may transmit the PPDU as required in the common field when they transmit the TB PPDU in IEEE 802.11 ax. The trigger type field in the common information field may be set to a base or FD trigger to indicate that this field is to trigger the transmission of the FD recipient. This field may not be needed or may be reserved if the FD transmission enable is set to a second state (e.g., "0") or the transmitter STA is the FD receiver. It should be noted that the AP transmit power subfield in the common information field as defined in IEEE 802.11ax may represent the requested power level of the transmitter STA.

The user information (Info) list field is set to allocate RU and other transmission information for the FD receiver STA and the preempting STA. Each user information field may be similar to the user information field in the basic trigger frame as defined in IEEE 802.11 ax.

The user information (Info) of the FD receiver field is set to indicate PPDU transmission requirements of the FD receiver STA. The FD receiver STA should transmit the PPDU for FD transmission following the requirements indicated in this field. This field may not be needed or may be reserved if FD transmission is allowed to be set to a second state (e.g., "0") or the transmitter STA is the FD receiver. It is possible that a plurality of user information of the FD receiver field may be carried in the same user information list.

The user information (Info) of the FD preemption field is set to indicate the PPDU transmission requirements of the preempting STA. The preempting STA should follow the requirements indicated in this field to send a preemption signal to the transmitter STA. This field may not be needed or may be reserved if the preemption allowed is set to a second state (e.g., "0") or the transmitter STA is the FD recipient.

DTX acknowledgement signal format

Fig. 30 shows an example embodiment 830 of a DTX acknowledgement signal format. The signal may be added in the middle of an ongoing transmission PPDU to indicate an interruption in PPDU transmission.

The STF field may be the same as an L-STF, EHT-STF, or other type of short training field as defined in IEEE 802.11, which may be used for a receiver STA to detect the start of a DTX acknowledgement signal during reception.

The LTF field may be the same as an L-LTF, EHT-LTF, or other type of long training field as defined in IEEE 802.11, which may be used for the receiver STA to estimate channel conditions.

The SIG field may be the same as the U-SIG as defined in IEEE 802.11be to carry information of the signal.

The DTX indication field is used to indicate that the purpose of the signal is to interrupt the current PPDU. For example, the field may be a one-bit indication. When it is set to a first state (e.g., "1"), it is a DTX acknowledgement signal for the current ongoing PPDU when the DTX time is interrupted. If the transmitter STA is an FD receiver STA and there is another ongoing transmission by the FD receiver STA, the FD receiver should also interrupt its transmission at DTX time. Otherwise, it is set to a second state (e.g., "0"). The bit may be a reserved bit in the U-SIG field.

The DTX time field indicates the time when the transmitter STA and the FD receiver STA interrupt their ongoing transmissions. This field may also be set to the number of OFDM symbols. For example, if the field is set to "n" OFDM symbols, the transmitter STA and the FD receiver STA interrupt their ongoing transmission after transmitting "n" OFDM symbols. In some cases, this field is not necessary. If there is no DTX time field, the transmitter STA and FD receiver STA should interrupt their ongoing transmissions immediately after they receive a DTX acknowledgement signal.

The EHT-LTF field may be the same as the field defined in IEEE 802.11 be. This field may provide the transmitter STA with a time to detect an interruption of the transmission of the FD receiver STA. This field may not be necessary if there is no FD recipient STA. If the transmitter STA does not detect an interruption of the transmission by the FD receiver STA, it may retransmit the DTX acknowledgement signal.

The data field may be used to carry additional information (such as BAR) to request BA from the receiver STA of the ongoing PPDU. When the STA receives the BAR, it should immediately transmit the BA.

The PE field is a packet extension field for the transmitter STA to receive feedback carried by the data field.

6.3. Preemption request signal format

Fig. 31 illustrates an example embodiment 840 of a preemption request signal format. The frame control field indicates the type of frame. The duration field contains the duration of the signal. The address 1 field contains the address of the recipient of the frame. The address 2 field contains the address of the sender of the frame. Address 3 contains the BSS ID of the sender of the frame. The sequence control field contains the fragment number and sequence number of the packet.

The HT control field may be the same as IEEE 802.11ax to provide additional information to preempt STAs. For example, this field may carry a BSR. The preempted STA receiving this field may estimate the channel resources required by the preempted STA to transmit the buffer reported by the BSR. The preempted STA may then decide whether to accept or reject the preemption request.

The data field carries the information of the preemption request.

The category and action fields indicate that the frame is a preemption request signal. If the preempted STA accepts the request, it interrupts its ongoing transmission and initiates the preempted transmission of the preempted STA. When the preempted STA accepts the request, it may send an Ack in response to the preempted STA. It should be noted that seemingly preempted STAs may decide to reject the request and not respond.

The BW field indicates the bandwidth required for the preempting STA to transmit in the preempting transmission. The BW value should be greater than the value used by the preempted STA's ongoing transmissions. The preempted STA may decide whether to accept or reject the request based on this information.

The priority field indicates the priority of the preemptive transmission requested by the preempting STA. The preempted STA may accept the request if the preempted transmission has a higher priority than the preempted STA's ongoing transmission. If the preempted STA is also an FD initiator, it may accept the request if the priority of the preempted transmission is higher than the priority of the ongoing transmission of both the FD initiator and the recipient STA.

The preemption time field indicates the time at which the preempting STA needs to transmit its preemption transmission. The preemption time may not be longer than the remaining time of the preempted STA's ongoing PPDU or the remaining TXOP duration as obtained by the preempted STA. Otherwise, the preempted STA may reject the preemption request.

7. General scope of the examples

Embodiments of the present technology may be described herein with reference to flowchart illustrations of methods and systems according to embodiments of the technology and/or procedures, algorithms, steps, operations, formulas, or other computational descriptions that may also be implemented as a computer program product. In this regard, each block or step of the flowcharts, and combinations of blocks (and/or steps) in the flowcharts, and any process, algorithm, step, operation, formula, or computational description can be implemented by various means such as hardware, firmware, and/or software including one or more computer program instructions embodied in computer readable program code. As will be appreciated, any such computer program instructions may be executed by one or more computer processors, including but not limited to general purpose or special purpose computers, or other programmable processing apparatus to produce a machine, such that the computer program instructions, which execute on the one or more computer processors or other programmable processing apparatus, create means for implementing the specified function or functions.

Accordingly, blocks and processes of the flowcharts, algorithms, steps, operations, formulas, or computational descriptions described herein support combinations of means for performing the specified function or functions, combinations of steps for performing the specified function or functions, and computer program instructions, such as embodied in computer readable program code logic means, for performing the specified function or functions. It will also be understood that each block of the flowchart illustrations, and any processes, algorithms, steps, operations, formulas or computational descriptions and combinations thereof described herein, can be implemented by special purpose hardware-based computer systems which perform the specified function(s) or step(s), or combinations of special purpose hardware and computer readable program code.

Additionally, such computer program instructions, such as embodied in computer-readable program code, may also be stored in one or more computer-readable memories or storage devices that can direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memories or storage devices produce an article of manufacture including instruction means which implement the function specified in the flowchart block or blocks. The computer program instructions may also be executed by a computer processor or other programmable processing apparatus to cause a series of operational steps to be performed on the computer processor or other programmable processing apparatus to produce a computer implemented process such that the instructions which execute on the computer processor or other programmable processing apparatus provide steps for implementing the functions specified in the flowchart block or blocks, process or blocks, algorithm or algorithms, step or steps, operation or operations, formula or formulas or computational description or descriptions.

It will also be appreciated that the term "programmed" or "program executable" as used herein refers to one or more instructions that can be executed by one or more computer processors to perform one or more functions as described herein. The instructions may be embodied in software, in firmware, or in a combination of software and firmware. The instructions may be stored locally on the device in a non-transitory medium, or may be stored remotely, such as on a server, or all or a portion of the instructions may be stored locally and remotely. The remotely stored instructions may be downloaded (pushed) to the device by user initiation or automatically based on one or more factors.

It will also be appreciated that as used herein, the terms processor, hardware processor, computer processor, central Processing Unit (CPU), and computer are synonymously used to denote a device capable of executing instructions and communicating with input/output interfaces and/or peripheral devices, and the terms processor, hardware processor, computer processor, CPU, and computer are intended to encompass single or multiple devices, single core or multi-core devices, and variations thereof.

From the description herein, it will be appreciated that the present disclosure encompasses multiple implementations of the present technology, including but not limited to the following:

an apparatus for wireless communication in a network, the apparatus comprising: (a) A wireless communication circuit as a Station (STA) that wirelessly communicates with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol configured to support carrier sense multiple access/collision avoidance (CSMA/CA); (b) a processor coupled to the STA; (c) A non-transitory memory storing instructions executable by the processor for communicating with other STAs and fulfilling different roles of the communication protocol; and (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (d) (i) performing an ongoing physical layer protocol data unit (PPDU) transmission by the station having Full Duplex (FD) capability; (d) (ii) receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission; (d) (iii) determining whether to accept the preemption request based on information in the preemption request; and (d) (iv) the STA now operating as a preempted STA interrupts ongoing transmissions when it accepts a preemption request from another STA operating as a preempted STA, and thus the preempted STA allows the preempted STA to use the channel.

An apparatus for wireless communication in a network, the apparatus comprising: (a) A wireless communication circuit as a Station (STA) that wirelessly communicates with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol configured to support carrier sense multiple access/collision avoidance (CSMA/CA); (b) a processor coupled to the STA; (c) A non-transitory memory storing instructions executable by the processor for communicating with other STAs and fulfilling different roles of the communication protocol; and (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (d) (i) performing an ongoing physical layer protocol data unit (PPDU) transmission by the station having Full Duplex (FD) capability; (d) (ii) wherein the preempted STA has punctured resources in its PPDU that can be used by the preempted STA to detect third party transmissions; (d) (iii) receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission; (d) (iv) determining whether to accept the preemption request based on information in the preemption request; and (d) (v) the STA now operating as a preempted STA interrupts ongoing transmissions when it accepts a preemption request from another STA operating as a preempted STA, and thus the preempted STA allows the preempted STA to use the channel.

A method for performing wireless communication in a network, the apparatus comprising: (a) A Station (STA) that wirelessly communicates with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol, the IEEE 802.11 protocol configured to allow different STAs to perform different roles during communication that supports carrier sense multiple access/collision avoidance (CSMA/CA); (b) Performing an ongoing physical layer protocol data unit (PPDU) transmission by the Full Duplex (FD) capable station; (c) Receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission; (d) Determining whether to accept the preemption request according to the information in the preemption request; and (e) in response to accepting a preemption request from another STA operating as a preempting STA, interrupting the ongoing transmission by the preempted STA and thereby allowing the preempted STA to transmit on the channel.

A wireless communication apparatus that performs packet transmission, wherein CSMA/CA is applied in a system/apparatus, a STA supporting full duplex transmission, comprising: (a) When the preempted STA is transmitting, the preempted STA detects a preemption request of the preempted STA; (b) The preempted STA interrupting its ongoing transmission if it accepts the preemption request; and (c) the preempted STA preempting transmissions of the preempted STA after the preempted STA interrupts its ongoing transmissions.

An apparatus or method of any preceding implementation, wherein the preempted STA has a puncturing resource in its PPDU that may be used by the preempted STA to detect third party transmissions.

An apparatus or method of any of the preceding implementations, wherein the preempted STA accepts preemption requests only from within its own BSS.

An apparatus or method of any of the preceding implementations, wherein the preempted STA chooses to reject the preemption request and continues its ongoing transmission.

An apparatus or method of any of the preceding implementations, wherein the preempted STA chooses to interrupt its ongoing transmissions and its simultaneous reception operations.

An apparatus or method of any of the foregoing implementations, wherein the preempted STA chooses to interrupt its ongoing transmission, but waits until the transmission of the current media access control service data unit (MSDU) or a-MSDU in the PPDU is completed before interrupting.

An apparatus or method of any preceding implementation, wherein the preempting STA sends a frame to initiate its preemption transmission by the preempting STA.

An apparatus or method of any preceding implementation, wherein the preempting STA is only allowed to perform preempting transmissions during a transmission opportunity (TXOP) as obtained by the preempted STA.

The apparatus or method of any of the preceding implementations, further comprising: (a) wherein the preempting STA has FD capability; and (b) wherein the preempted STA transmits a PPDU to the preempted STA during the time that the preempted STA is transmitting a preempted transmission to the preempted STA.

An apparatus or method of any preceding implementation, wherein the preempted STA disables the preempted transmission during the spatial reuse transmission.

An apparatus or method of any preceding implementation, wherein the preempted STA disables the preempted transmission during the coordinated MAP transmission.

An apparatus or method of any of the preceding implementations, wherein the preempted STA may have a puncturing resource in its PPDU such that the preempted STA may use the puncturing resource to detect any third party transmissions.

An apparatus or method of any of the preceding implementations, wherein the preempted STA may only accept preemption requests from the same BSS.

An apparatus or method of any of the preceding implementations, wherein the preempted STA may refuse the preempted transmission request.

An apparatus or method of any of the preceding implementations, wherein the preempted STA may interrupt its ongoing transmissions of the transmission and simultaneous reception.

An apparatus or method of any of the preceding implementations, wherein the preempted STA may interrupt the ongoing transmission after completing a current MSDU or a-MSDU in the PPDU.

An apparatus or method of any of the preceding implementations, wherein the preempting STA may send a frame to initiate preemption transmissions of the preempting STA.

An apparatus or method of any of the preceding implementations, wherein the preempting STA can only have preempting transmissions during a TXOP obtained by the preempted STA.

An apparatus or method of any of the preceding implementations, wherein the preempting STA may transmit a PPDU to the preempted STA during a time when the preempting STA is transmitting a preempted transmission to the preempted STA (i.e., a full duplex transmission between the preempting STA and the preempted STA).

An apparatus or method of any preceding implementation, wherein the STA may disable preemption transmission during the spatial reuse transmission.

An apparatus or method of any of the preceding implementations, wherein the STA may disable preemption transmissions during the coordinated MAP transmissions.

As used herein, the term "implementation" is intended to include, without limitation, embodiments, examples, or other forms of practicing the techniques described herein.

As used herein, the singular terms "a," "an," and "the" may include plural referents unless the context clearly dictates otherwise. References to an object in the singular are not intended to mean "one and only one" unless explicitly so stated, but rather "one or more".

The construction of words within this disclosure such as "A, B and/or C" describe where A, B or C may be present, or any combination of items A, B and C. The phrase construct such as "at least one of …" which subsequently lists a set of elements indicates that at least one of those set of elements is present, including any possible combination of listed elements as applicable.

Reference in the present disclosure to "one embodiment," "at least one embodiment," or similar embodiment phrases, indicates that a particular feature, structure, or characteristic described in connection with the described embodiment is included in at least one embodiment of the present disclosure. Thus, these various embodiment phrases are not necessarily all referring to the same embodiment, or to particular embodiments different from all other embodiments described. The embodiment language should be construed to mean that a particular feature, structure, or characteristic of a given embodiment may be combined in any suitable manner in one or more embodiments of the disclosed apparatus, system, or method.

As used herein, the term "group" refers to a collection of one or more objects. Thus, for example, a group of objects may include a single object or multiple objects.

Relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

The terms "comprises," "comprising," "has," "having," "includes," "including," "containing," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, or comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The foregoing elements of "comprising … one," "having … one," "including … one," "comprising … one," and the like do not, without further constraint, preclude the presence of additional identical elements in a process, method, article, or apparatus that comprises, has, comprises, or comprises the element.

As used herein, the terms "about," "approximately," "substantially," and "approximately" or any other version thereof are used to describe and illustrate minor variations. When used in connection with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely and instances where it occurs approximately. When used in conjunction with a numerical value, the term may refer to a range of variation of less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, "substantially" aligned may refer to a range of angular variation of less than or equal to ±10°, such as less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

Furthermore, amounts, ratios, and other numerical values may sometimes be presented herein in a range format. It will be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include the numerical values explicitly recited as the limits of the range, as well as the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, ratios in the range of about 1 to about 200 are understood to include the explicitly mentioned limitations of about 1 and about 200, as well as individual ratios such as about 2, about 3, and about 4, as well as subranges such as about 10 to about 50, about 20 to about 100, and so forth.

The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. A device or structure that is "configured" in a certain way is configured at least in that way, but may also be configured in ways that are not listed.

The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or element of the techniques described herein or any or all the claims.

Furthermore, in the foregoing disclosure, various features may be combined together in various embodiments to simplify the present disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Inventive subject matter may lie in less than all features of a single disclosed embodiment.

The Abstract of the disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

It will be appreciated that the practice of certain jurisdictions may require that one or more portions of the present disclosure be deleted after the application is filed. Accordingly, the reader should review the filed application for the original content of the present disclosure. Any deletion of the present disclosure should not be construed as a disclaimer, sink, or dedicate to the public of any subject matter of the initially filed application.

The following claims are hereby incorporated into the disclosure, with each claim standing on its own as a separately claimed subject matter.

Although the description herein contains many specifics, these should not be construed as limiting the scope of the present disclosure but merely as providing illustrations of some of the presently preferred embodiments. Accordingly, it will be appreciated that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art.

All structural and functional equivalents to the elements of the disclosed embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. Absent claim elements herein are to be construed as "means plus function" elements unless the element is explicitly recited using the phrase "means for …". Absent claim elements herein are to be construed as "step plus function" elements unless the element is explicitly recited using the phrase "step for …".

Claims (20)

1. An apparatus for wireless communication in a network, the apparatus comprising:

(a) A wireless communication circuit as a Station (STA) that wirelessly communicates with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol configured to support carrier sense multiple access/collision avoidance (CSMA/CA);

(b) A processor coupled to the STA;

(c) A non-transitory memory storing instructions executable by the processor for communicating with other STAs and fulfilling different roles of communication protocols; and is also provided with

(d) Wherein the instructions, when executed by the processor, perform one or more steps comprising:

(i) Performing an ongoing physical layer protocol data unit (PPDU) transmission by the Full Duplex (FD) capable station;

(ii) Receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission;

(iii) Determining whether to accept the preemption request according to the information in the preemption request; and

(iv) The STA, now operating as a preempted STA, interrupts ongoing transmissions when it accepts a preemption request from another STA operating as a preempted STA, and thus the preempted STA allows the preempted STA to use the channel.

2. The apparatus of claim 1, wherein the preempted STA has a puncturing resource in its PPDU that can be used by the preempted STA to detect third party transmissions.

3. The apparatus of claim 1, wherein the preempted STA accepts preemption requests only from within its own Basic Service Set (BSS).

4. The apparatus of claim 1, wherein the preempted STA chooses to reject the preemption request and continues its ongoing transmission.

5. The apparatus of claim 1, wherein the preempted STA chooses to interrupt its ongoing transmission and its simultaneous reception operation.

6. The apparatus of claim 1, wherein the preempted STA chooses to interrupt its ongoing transmission but waits until transmission of a current media access control service data unit (MSDU) or a-MSDU in a PPDU is completed.

7. The apparatus of claim 1, wherein the preempting STA sends a frame to initiate its preempting transmission by the preempting STA.

8. The apparatus of claim 1, wherein the preempted STA is allowed to perform preempted transmissions only during a transmit opportunity (TXOP) obtained by the preempted STA.

9. The apparatus of claim 1, further comprising:

(a) Wherein the preempting STA has FD capability; and is also provided with

(b) Wherein the preempted STA transmits a PPDU to the preempted STA during a time when the preempted STA is transmitting a preempted transmission to the preempted STA.

10. The apparatus of claim 1, wherein the preempted STA disables preempted transmissions during spatial reuse transmissions.

11. The apparatus of claim 1, wherein the preempted STA disables preemption transmissions during a coordinated MAP transmission.

12. An apparatus for wireless communication in a network, the apparatus comprising:

(a) A wireless communication circuit as a Station (STA) that wirelessly communicates with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol configured to support carrier sense multiple access/collision avoidance (CSMA/CA);

(b) A processor coupled to the STA;

(c) A non-transitory memory storing instructions executable by the processor for communicating with other STAs and fulfilling different roles of communication protocols; and is also provided with

(d) Wherein the instructions, when executed by the processor, perform one or more steps comprising:

(i) Performing an ongoing physical layer protocol data unit (PPDU) transmission by the Full Duplex (FD) capable station;

(ii) Wherein the preempted STA has a puncturing resource in its PPDU that can be used by the preempted STA to detect third party transmissions;

(iii) Receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission;

(iv) Determining whether to accept the preemption request according to the information in the preemption request; and

(v) The STA, now operating as a preempted STA, interrupts ongoing transmissions when it accepts a preemption request from another STA operating as a preempted STA, and thus the preempted STA allows the preempted STA to use the channel.

13. The apparatus of claim 12, wherein the preempted STA accepts preemption requests only from within its own Basic Service Set (BSS).

14. The apparatus of claim 12, wherein the preempted STA chooses to reject the preemption request and continues its ongoing transmission.

15. The apparatus of claim 12, wherein the preempted STA, upon accepting a preemption request, chooses to interrupt its ongoing transmissions and its reception operations.

16. The apparatus of claim 12, wherein the preempted STA chooses to interrupt its ongoing transmission but waits until transmission of a current media access control service data unit (MSDU) or a-MSDU in a PPDU is completed.

17. The apparatus of claim 12, wherein the preempting STA sends a frame to initiate its preempting transmission by the preempting STA.

18. The apparatus of claim 12, wherein the preempted STA is allowed to perform preempted transmissions only during a transmit opportunity (TXOP) obtained by the preempted STA.

19. The apparatus of claim 12, wherein the preempted STA disables preempted transmissions during spatial reuse transmissions or during coordinated MAP transmissions.

20. A method for performing wireless communications in a network, the apparatus comprising:

(a) A Station (STA) that communicates wirelessly with other STAs over a Wireless Local Area Network (WLAN) in an IEEE 802.11 protocol, the IEEE 802.11 protocol configured to allow different STAs to perform different roles during communications that support carrier sense multiple access/collision avoidance (CSMA/CA);

(b) Performing an ongoing physical layer protocol data unit (PPDU) transmission by the Full Duplex (FD) capable station;

(c) Receiving, at the STA, a preemption request issued by another STA while the STA is performing the ongoing transmission;

(d) Determining whether to accept the preemption request according to the information in the preemption request; and

(e) In response to accepting a preemption request from another STA operating as a preempting STA, the ongoing transmission is interrupted by the preempted STA and the preempted STA is thus permitted to transmit on the channel.