Techniques for multi ap txop sharing

Abstract

Provided are techniques such as methods including, in a first access point (AP) device, transmitting a polling frame to indicate an available sharing opportunity in a channel; determining if the available sharing opportunity is to be transferred to a second AP device; and if the available sharing opportunity is not to be returned, transmitting a control frame to release the channel.

Description

SPECIFICATIONTECHNIQUES FOR MULTI AP TXOP SHARINGCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 588,263 filed October 05, 2023, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to multi AP transmission opportunity sharing in a wireless network.BACKGROUND

[0003] Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of standards for implementing wireless local area network communication in various frequencies, including but not limited to the 2.4 gigahertz (GHz), 5 GHz, 6 GHz, and 60 GHz bands. These standards define the protocols that enable Wi-Fi devices to communicate with each other. The IEEE 802.11 family of standards has evolved over time to accommodate higher data rates, improved security, and better performance in different environments. Some of the most widely used standards include 802.11a, 802.11b, 802.11g, 802.1 In, 802.1 lac, and 802.1 lax (also known as “Wi-Fi 6”). These standards specify the modulation techniques, channel bandwidths, and other technical aspects that facilitate interoperability between devices from various manufacturers. IEEE 802.11 has played an important role in the widespread adoption of wireless networking in homes, offices, and public spaces, enabling users to connect their devices to the internet and each other without the need for wired connections.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The disclosure will be more fully understood from the detailed description provided below and the accompanying drawings that depict various embodiments of the disclosure. However, these drawings should not be interpreted as limiting the disclosure to the specific embodiments shown; they are provided for explanation and understanding only.

[0005] Figure 1 A shows a wireless local area network (WLAN) with a basic service set (BSS) that includes a plurality of wireless devices.

[0006] Figure IB is a table illustrating operational parameters for various WiFi versions leading up to 802.1 Ibn.

[0007] Figure 2 illustrates a schematic block diagram of a wireless device in accordance with some embodiments.

[0008] Figure 3 A illustrates components of a WLAN device configured to transmit data in accordance with some embodiments.

[0009] Figure 3B illustrates components of a WLAN device configured to receive data in accordance with some embodiments.

[0010] Figure 4 illustrates Inter-Frame Space (IFS) relationships.

[0011] Figure 5 illustrates a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collisions between frames in a channel in accordance with some embodiments.

[0012] Figure 6A is a diagram showing the general structure of a trigger frame.

[0013] Figure 6B illustrates an example trigger frame uplink (UL) transmission scenario in accordance with some embodiments.

[0014] Figure 6C illustrates an example trigger frame downlink (UL) transmission scenario in accordance with some embodiments.

[0015] Figures 7A and 7B show the general structures for EHT (WiFi 7) multi user and trigger based physical layer protocol data unit (PPDU) frames, respectively.

[0016] Figure 7C is a table listing the fields, along with additional information, for a TB PPDU.

[0017] Figure 7D is a table listing descriptions and information for sub fields in a universal signal (U-SIG) field for either a MU or TB PPDU frame.

[0018] Figure 8 is a diagram illustrating three BSSs with overlapping areas of coverage in accordance with some embodiments.

[0019] Figure 9 shows an operational resource sharing scenario between a sharing AP and a shared AP in accordance with some embodiments.

[0020] Figure 10 shows the general format for a traditional PS-Poll frame.

[0021] Figure 11 A is a diagram showing a frame format for a PS Poll frame with available TXOP duration indication capabilities in accordance with some embodiments.

[0022] Figure 1 IB is a table describing the functions of the Duration / ID field of Figure 11 A based on the values of bits 14 and 15 in accordance with some embodiments.

[0023] Figure 12 is a diagram showing an operational sequence for an AP responding to a available sharing opportunity indication frame when it wants to receive the sharing opportunity in accordance with some embodiments.

[0024] Figure 13 is a diagram showing an operational sequence for an AP responding to a available sharing opportunity indication frame when it does not want to receive the sharing opportunity in accordance with some embodiments.

[0025] Figure 14 is a diagram showing an operational sequence for when an AP does not want to receive the sharing opportunity in accordance with some additional embodiments.

[0026] Figure 15A is a flow diagram showing a routine for a shared AP to indicate available TXOP in accordance with some embodiments.

[0027] Figure 15B is a flow diagram showing a routine for an AP to process an indication from a shared AP that it has available TXOP in accordance with some embodiments.DETAILED DESCRIPTION

[0028] As mentioned above, some of the objectives of the next generation of wireless networking standards (e.g., IEEE 802.1 Ibe or beyond) include improving data rate and communication range. However, improving data rate and improving communication range are often competing objectives (there is a tradeoff between data rate and communication range). As will be discussed further below, with current WiFi standards (e.g., WiFi 6 and beyond), APs are able to share transmission opportunity resources (e.g., TXOPs) between one another, increasing channel utilization and overall wireless resource efficiency. However, in some situations, an AP with the sharing opportunity (e.g., a sharing AP or a shared AP that cannot use all of its shared TXOP) cannot use, or otherwise does not need, all of the allocated TXOP duration. In such cases, the AP should be able to give the available TXOP to another AP such as back to a sharing AP or even to a different AP. If another AP desires to receive the available TXOP, it should be able to receive it. However, there may not always be an AP, even the sharing AP, that has a need to use the available TXOP duration. In such cases, when there is not an AP with a need to use the available TXOP resource, other stations should be notified that the channel is free in order to reduce resource waste. Accordingly, in some embodiments, frames such as polling frames (e.g., PS-Poll frames with enhanced functionality or other polling frames) may be used to facilitate efficient allocation of available TXOP resources.

[0029] In the following detailed description, certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in different ways without departing fromthe spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

[0030] Figure 1 A shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104). Each of the wireless devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments (e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In the process of wireless communication, a transmitting station (STA) creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to a receiving STA. The receiving STA then receives, detects, and processes the PPDU. In some embodiments, the MAC layer of a wireless device 104 may initiate transmission of a frame to another wireless device 104 by passing a PHY-TXSTART. request (TXVECTOR) to the PHY layer. The TXVECTOR provides parameters for generating and / or transmitting a corresponding frame. Similarly, a PHY layer of a receiving wireless device may generate an RXVECTOR, which includes parameters of a received frame and is passed to a MAC layer for processing.

[0031] The plurality of wireless devices 104 may include a wireless device 104A that is an access point (sometimes referred to as an AP station or AP STA) and the other wireless devices 104B1-104B4 that are non-AP stations (sometimes referred to as non-AP STAs). Alternatively, all the plurality of wireless devices 104 may be non-AP STAs in an ad-hoc networking environment. In general, the AP STA (e.g., wireless device 104 A) and the non-AP STAs (e.g., wireless devices 104B1-104B4) may be collectively referred to as STAs. However, for ease of description, only the non-AP STAs may be referred to as STAs unless the context indicates otherwise. Although shown with four non-AP STAs (e.g., the wireless devices 104B1- IO4B4), the WLAN 100 may include any number of non-AP STAs (e.g., one or more wireless devices 104B).

[0032] Figure IB is a table illustrating operational parameters for various WiFi versions leading up to 802.1 Ibn, also referred to as WiFi 8 or UHR (Ultra High Reliability). The IEEE 802.1 Ibn (UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi. As shown in Figure IB, the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video- over- WLAN, gaming, AR, and VR. It is noted that various characteristics of UHR (e.g., maxPHY rate, PHY rate enhancement, bandwidth / number of spatial streams, and operating bands) are still being considered.

[0033] The focus of IEEE 802.1 Ibe (EHT or WiFi 7) is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands. In addition to peak PHY rate, different candidate features are under discussion. These candidate features include (1) a 320 MHz bandwidth and a more efficient utilization of a noncontiguous spectrum, (2) multi -band / multi -channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.

[0034] The focus of IEEE 802.1 Ibn (UHR) is still under discussion, with candidate features including MLO enhancements (e.g., in terms of increased throughput / reliability and decreased latency), latency and reliability improvements (e.g., multi-AP coordination to support low latency traffic), bandwidth expansion (e.g., to 240, 480, 640 MHz), aggregated PPDU (A- PPDU), enhanced multi-link single-radio (eMLSR) extensions to AP, roaming improvements, and power-saving schemes for prolonging battery life.

[0035] Some features, such as increasing the bandwidth and the number of spatial streams, are solutions that have been proven to be effective in previous projects focused on increasing link throughput and on which feasibility demonstration is achievable.

[0036] With respect to operational bands (e.g., 2.4 / 5 / 6 GHz) for IEEE 802.1 Ibe, more than 1 GHz of additional unlicensed spectrum is likely to be available because the 6 GHz band (5.925 - 7.125 GHz) is being considered for unlicensed use. This would allow APs and STAs to become tri-band devices. Larger than 160 MHz data transmissions (e.g., 320 MHz or 640 MHz) could be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160MHz data could be transmitted in the 6 GHz band. For example, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0037] Figure 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment. The wireless device 104 may be the wireless device 104A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1. The wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the inputinterfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.

[0038] The baseband processor 210 performs baseband signal processing and includes a MAC processor 212 and a PHY processor 222. The baseband processor 210 may utilize the memory 232, which may include a non-transitory computer / machine readable medium having software (e.g., computer / machine programing instructions) and data stored therein.

[0039] In an embodiment, the MAC processor 212 includes a MAC software processing unit 214 and a MAC hardware processing unit 216. The MAC software processing unit 214 may implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in the software stored in the storage device 232. The MAC hardware processing unit 216 may implement a second plurality of functions of the MAC layer in specialpurpose hardware. However, the MAC processor 212 is not limited thereto. For example, the MAC processor 212 may be configured to perform the first and second plurality of functions entirely in software or entirely in hardware according to an implementation.

[0040] The PHY processor 222 includes a transmitting (TX) signal processing unit (SPU) 224 and a receiving (RX) SPU 226. The PHY processor 222 implements a plurality of functions of the PHY layer. These functions may be performed in software, hardware, or a combination thereof according to an implementation.

[0041] Functions performed by the transmitting SPU 224 may include one or more of Forward Error Correction (FEC) encoding, stream parsing into one or more spatial streams, diversity encoding of the spatial streams into a plurality of space-time streams, spatial mapping of the space-time streams to transmit chains, inverse Fourier Transform (iFT) computation, Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and the like. Functions performed by the receiving SPU 226 may include inverses of the functions performed by the transmitting SPU 224, such as GI removal, Fourier Transform computation, and the like.

[0042] The RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. The RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) and provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.

[0043] The antenna unit 250 includes one or more antennas. When Multiple-Input Multiple- Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antenna unit 250 may include a plurality of antennas. In an embodiment, the antennas in the antenna unit 250 may operate as abeam-formed antenna array. In an embodiment, the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.

[0044] The input interfaces 234 receive information from a user, and the output interfaces 236 output information to the user. The input interfaces 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, and the like. The output interfaces 236 may include one or more of a display device, touch screen, speaker, and the like.

[0045] As described herein, many functions of the WLAN device 104 may be implemented in either hardware or software. Which functions are implemented in software and which functions are implemented in hardware will vary according to constraints imposed on a design. The constraints may include one or more of design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.

[0046] As described herein, a wide variety of electronic devices, circuits, firmware, software, and combinations thereof may be used to implement the functions of the components of the WLAN device 104. Furthermore, the WLAN device 104 may include other components, such as application processors, storage interfaces, clock generator circuits, power supply circuits, and the like, which have been omitted in the interest of brevity.

[0047] Figure 3 A illustrates components of a WLAN device 104 configured to transmit data according to an embodiment, including a transmitting (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In an embodiment, the TxSP 324, the RF transmitter 342, and the antenna 352 correspond to the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0048] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (TFT) 306, and a guard interval (GI) inserter 308.

[0049] The encoder 300 receives and encodes input data. In an embodiment, the encoder 300 includes a forward error correction (FEC) encoder. The FEC encoder may include a binary convolution code (BCC) encoder followed by a puncturing device. The FEC encoder may include a low-density parity-check (LDPC) encoder.

[0050] The TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 0s or Is. When the encoder 300 performs the BCC encoding, the TxSP 324 may further include an encoder parser for demultiplexing the scrambled bits among a plurality of BCC encoders. If LDPC encoding is used in the encoder, the TxSP 324 may not use the encoder parser.

[0051] The interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein. The interleaver 302 may apply the interleaving only when theencoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.

[0052] The mapper 304 maps the sequence of bits output from the interleaver 302 to constellation points. If the encoder 300 performed LDPC encoding, the mapper 304 may also perform LDPC tone mapping in addition to constellation mapping.

[0053] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may include a plurality of interleavers 302 and a plurality of mappers 304 according to a number of spatial streams (NSS) of the transmission. The TxSP 324 may further include a stream parser for dividing the output of the encoder 300 into blocks and may respectively send the blocks to different interleavers 302 or mappers 304. The TxSP 324 may further include a space-time block code (STBC) encoder for spreading the constellation points from the spatial streams into a number of space-time streams (NSTS) and a spatial mapper for mapping the space-time streams to transmit chains. The spatial mapper may use direct mapping, spatial expansion, or beamforming.

[0054] The IFT 306 converts a block of the constellation points output from the mapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper) to a time domain block (i.e., a symbol) by using an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT). If the STBC encoder and the spatial mapper are used, the IFT 306 may be provided for each transmit chain.

[0055] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming. The TxSP 324 may perform the insertion of the CSD before or after the IFT 306. The CSD may be specified per transmit chain or may be specified per space-time stream. Alternatively, the CSD may be applied as a part of the spatial mapper.

[0056] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0057] The GI inserter 308 prepends a GI to each symbol produced by the IFT 306. Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0058] The RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352. When the TxSP 324 performs a MIMO or MU-MIMO transmission, the GI inserter 308 and the RF transmitter 342 may be provided for each transmit chain.

[0059] Figure 3B illustrates components of a WLAN device 104 configured to receive data according to an embodiment, including a Receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354. In an embodiment, the RxSP 326, RF receiver 344, and antenna 354 may correspond to the receiving SPU 226, the RF receiver 244, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0060] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0061] The RF receiver 344 receives an RF signal via the antenna 354 and converts the RF signal into symbols. The GI remover 318 removes the GI from each of the symbols. When the received transmission is a MIMO or MU-MIMO transmission, the RF receiver 344 and the GI remover 318 may be provided for each receive chain.

[0062] The FT 316 converts each symbol (that is, each time domain block) into a frequency domain block of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). The FT 316 may be provided for each receive chain.

[0063] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBC decoder for de-spreading the constellation points from the space-time streams into one or more spatial streams.

[0064] The demapper 314 de-maps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone de-mapping before performing the constellation de-mapping.

[0065] The deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314. The deinterleaver 312 may perform the deinterleaving only when the received transmission was encoded using BCC encoding, and otherwise may output the stream output by the demapper 314 without performing deinterleaving.

[0066] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may use a plurality of demappers 314 and a plurality of deinterleavers 312 corresponding to the number of spatial streams of the transmission. In this case, the RxSP 326 may further include a stream deparser for combining the streams output from the deinterleavers 312.

[0067] The decoder 310 decodes the streams output from the deinterleaver 312 or the stream deparser. In an embodiment, the decoder 310 includes an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

[0068] The RxSP 326 may further include a descrambler for descrambling the decoded data. When the decoder 310 performs BCC decoding, the RxSP 326 may further include an encoder deparser for multiplexing the data decoded by a plurality of BCC decoders. When the decoder 310 performs the LDPC decoding, the RxSP 326 may not use the encoder deparser.

[0069] Before making a transmission, wireless devices such as wireless device 104 will assess the availability of the wireless medium using Clear Channel Assessment (CCA). If the medium is occupied, CCA may determine that it is busy, while if the medium is available, CCA determines that it is idle.

[0070] The PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA (e.g., a wireless device 104) is capable of transmitting and receiving Physical Layer (PHY) Protocol Data Units (PPDUs) (also referred to as PLCP (Physical Layer Convergence Procedure) Protocol Data Units) that are compliant with the mandatory PHY specifications. A PHY specification defines a set of Modulation and Coding Schemes (MCS) and a maximum number of spatial streams. Some PHY entities define downlink (DL) and uplink (UL) Multi-User (MU) transmissions having a maximum number of space-time streams (STS) per user and employing up to a predetermined total number of STSs. A PHY entity may provide support for 10 Megahertz (MHz), 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz contiguous channel widths and support for an 80+80, 80+160 MHz, and 160+160 MHz non-contiguous channel width. Each channel includes a plurality of subcarriers, which may also be referred to as tones. A PHY entity may define signaling fields denoted as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), and the like within a PPDU by which some necessary information about PHY Service Data Unit (PSDU) attributes are communicated. The descriptions below, for sake of completeness and brevity, refer to OFDM-based 802.11 technology. Unless otherwise indicated, a station refers to a non-AP STA.

[0071] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an Access Category (AC) ‘i’ (AIFS[i]). Figure 4 also illustrates a slot time and a data frame is used for transmission of data forwarded to a higher layer. As shown, a WLAN device 104 transmits thedata frame after performing backoff if a DIFS has elapsed during which the medium has been idle.

[0072] A management frame may be used for exchanging management information, which is not forwarded to the higher layer. Subtype frames of the management frame include a beacon frame, an association request / response frame, a probe request / response frame, and an authentication request / response frame.

[0073] A control frame may be used for controlling access to the medium. Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame.

[0074] When the control frame is not a response frame of another frame, the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle. When the control frame is the response frame of another frame, the WLAN device 104 transmits the control frame after a SIFS has elapsed without performing backoff or checking whether the medium is idle.

[0075] A WLAN device 104 that supports Quality of Service (QoS) functionality (that is, a QoS STA) may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed. When transmitted by the QoS STA, any of the data frame, the management frame, and the control frame, which is not the response frame, may use the AIFS[AC] of the AC of the transmitted frame.

[0076] A WLAN device 104 may perform a backoff procedure when the WLAN device 104 that is ready to transfer a frame finds the medium busy. The backoff procedure includes determining a random backoff time composed of N backoff slots, where each backoff slot has a duration equal to a slot time and N being an integer number greater than or equal to zero. The backoff time may be determined according to a length of a Contention Window (CW). In an embodiment, the backoff time may be determined according to an AC of the frame. All backoff slots occur following a DIFS or Extended IFS (EIFS) period during which the medium is determined to be idle for the duration of the period.

[0077] When the WLAN device 104 detects no medium activity for the duration of a particular backoff slot, the backoff procedure shall decrement the backoff time by the slot time. When the WLAN device 104 determines that the medium is busy during a backoff slot, the backoff procedure is suspended until the medium is again determined to be idle for the duration of a DIFS or EIFS period. The WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.

[0078] The backoff procedure operates so that when multiple WLAN devices 104 are deferring and execute the backoff procedure, each WLAN device 104 may select a backoff time using a random function and the WLAN device 104 that selects the smallest backoff time may win the contention, reducing the probability of a collision.

[0079] Figure 5 illustrates a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collisions between frames in a channel according to an embodiment. The distributed nature of channel access network such as IEEE 802.11 WLANs makes the carrier sense mechanism important for collision free operation. The physical carrier sense of one STA is responsible for detecting the transmissions of other STAs, but it may be impossible to detect every case in some circumstances. For example, one STA which may be a long distance away from another STA may see the medium as idle and begin transmitting frames. To overcome this hidden node issue, the network allocation vector (NAV) has been introduced. However, as the IEEE 802.11 standards evolve to include multiple users’ simultaneously transmitting / receiving within a BSS such as with a UL / DL MU transmission in cascaded manner, modified or newly defined mechanisms may be needed. As used herein, multi-user (MU) transmission refers to cases where multiple frames are transmitted to or from multiple STAs simultaneously using different resources. Examples of different resources are different frequency resources in OFDMA transmissions and different spatial streams in MU- MIMO transmissions. DL-OFDMA, DL-MU-MIMO, UL-OFDMA, UL-MU-MIMO and OFDMA with MU-MIMO are examples of MU transmissions.

[0080] Figure 5 shows a first station STA1 transmitting data, a second station STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received. The stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.

[0081] The station STA1 may determine whether the channel is busy by carrier sensing. The station STA1 may determine channel occupation / status based on an energy level in the channel or an autocorrelation of signals in the channel, or may determine the channel occupation by using a network allocation vector (NAV) timer.

[0082] After determining that the channel is not used by other devices (that is, that the channel is IDLE) during a DIFS (and performing backoff if required), the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2. Upon receiving the RTS frame, after a SIFS the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame. If Dual-CTS is enabled and the station STA2 is an AP, the AP may send two CTS frames inresponse to the RTS frame (e.g., a first CTS frame in a non-High Throughput format and a second CTS frame in the HT format).

[0083] When the station STA3 receives the RTS frame, it may set a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using duration information included in the RTS frame. When the station STA3 receives the CTS frame, it may set the NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, the station STA3 may update the NAV timer of the station STA3 by using duration information included in the new frame. The station STA3 does not attempt to access the channel until the NAV timer expires.

[0084] When the station STA1 receives the CTS frame from the station STA2, it may transmit a data frame to the station STA2 after a SIFS period elapses from a time when the CTS frame has been completely received. Upon successfully receiving the data frame, the station STA2 may transmit an ACK frame as a response to the data frame after a SIFS period elapses.

[0085] When the NAV timer expires, the third station STA3 may determine whether the channel is busy using the carrier sensing. Upon determining that the channel is not used by other devices during a DIFS period after the NAV timer has expired, the station STA3 may attempt to access the channel after a contention window elapses according to a backoff process.

[0086] When Dual-CTS is enabled, a station that has obtained a transmission opportunity (TXOP) and that has no data to transmit may transmit a CF-End frame to cut short the TXOP. An AP receiving a CF-End frame having a Basic Service Set Identifier (BSSID) of the AP as a destination address may respond by transmitting two more CF-End frames: a first CF-End frame using Space Time Block Coding (STBC) and a second CF-End frame using non-STBC. A station receiving a CF-End frame resets its NAV timer to 0 at the end of the PPDU containing the CF-End frame. Figure 5 shows the station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.

[0087] Figure 6A is a diagram showing the general structure of a trigger frame. The function of the trigger frame is to allocate resources and solicit one or more Trigger-based (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from associated stations including both AP and non-AP STAs. Among other things, they are used by APs to allocate resources for multi-user Orthogonal Frequency Division Multiple Access (OFDMA) transmissions. They specify how bandwidth and time slots should be divided among multiple STAs, enabling simultaneous datatransmission from multiple users without interference. This is important for improving overall network efficiency and throughput, especially in environments with high user density.

[0088] As illustrated in the figure, trigger frames generally include several different sections including a MAC (media access control) header section 605, a common information section 610, and a user information section 615. The MAC header includes several fields that facilitate communication between devices. For example, they may include frame control (FC), duration, receiver address (RA), and transmitter address (TA) fields as shown. The FC field indicates protocol Version, type, and several different flags for parameters such as power management. The duration field indicates the duration for which the medium is reserved, or in some implementations, it may carry the association identifier (AID) in certain contexts. The RA field indicates the address of a recipient STA, and the TA field indicates the address of the transmitting STA. The MAC header may also include fields for sequence and QoS Control.

[0089] Trigger frames have specific subfields within the frame Control field that are used for its operation including the trigger frame type, e.g., basic trigger, MU-BAR (multi-user block acknowledgment request, and MU-RTS (multi-user request to send. Each of these subtypes has unique characteristics and requirements for operation, especially in multi-user scenarios where coordination is important for efficient communication.

[0090] The common Info section 610 includes parameters such as the expected uplink length, bandwidth, guard interval, and the transmit power used by the AP. These parameters help STAs prepare for their upcoming transmissions.

[0091] The different fields in the common info field serve to inform the responding STAs on how they should set up the frame in the response. The response to a MU-RTS is a legacy CTS frame in the non-HT format. At 5GHz that means legacy OFDM. Most of the subfields in the common info field for MU-RTS may therefore not be needed. For the included fields, trigger type is set to 3 for MU-RTS requests; More TF is used for TWT or power save with UORA (otherwise set to 00; and the CS Required is set to 0 if the responding STAs are not required to consider the medium or the NAV in determining whether or not to respond. CS Required is set to 1 if responding STAs are required to use ED (Energy Detect) to sense and consider the medium and the NAV in determining whether or not to respond. The UL BW is usually to describe the bandwidth of the response in the TB PPDU, but for MU-RTS, it may describe the bandwidth of the frame carrying the MU-RTS (e.g., 0=20 MHz, 1=40 MHz, 2=80 MHz, and 3=80 + 80 MHz or 160 MHz).

[0092] The user info section 615 includes details for each participating STA, such as Association IDs (AIDs), resource unit (RU) allocations, modulation and coding scheme (MCS),and an expected received signal strength indicator (RSSI). This information allows each STA to know its specific transmission parameters. The AID12 field indicates the STA-id (associations ID) for each recipient. Other values used in this space are used in other variants of the trigger frame. RU allocation is used to indicate which primary channel the responding CTS should be sent on. This is particular to 40 MHz and 80 MHZ channels, whether the primary channel are the lowest channel, next lowest channel, and so on. The user info fields are typically repeated for every STA that is a recipient of the MU-RTS. The receiving STAs are addressed by their association ID, STA-id, not by MAC-addresses as in legacy RTS. There may be other information depending on specific trigger frame types. For example, it may also include an allocation duration subfield in the User Information for a TXS (TXOP Sharing) frame. The User Info field in a trigger frame, such as in a MU-RTS trigger frame, may include an allocation duration subfield. This subfield indicates a time allocated by the AP for the STA to transmit during the TXOP. The field can contain an allocation duration subfield, which indicates the duration of time allocated for P2P communications associated with the client device. This allocation duration subfield is used for managing the transmission time and allowing other devices to set their network allocation vectors (NAVs) accordingly.

[0093] Figure 6B illustrates an example trigger frame uplink (UL) transmission scenario in accordance with some embodiments. In the IEEE 802.11 specification versions since 802.1 lax (WiFi 6), the trigger frame plays a useful role in facilitating both uplink and downlink multi-user (MU) transmissions.

[0094] The trigger frame contains information required by the responding STAs to send their Uplink TB PPDUs. This information includes the Trigger type, which specifies the type of TB PPDU expected, and the Uplink Length (UL Length), which indicates the duration of the uplink transmission.

[0095] With the example scenario of Figure 6B, an access point (AP) operating in an 80 MHz bandwidth environment sends a trigger frame to multiple associated STAs to allow them to perform uplink data transmissions. Upon receiving the Trigger frame, the STAs respond by sending their respective CTS response frames. CTS (clear to send) frames are the response to a MU-RTS. All STAs that are addressed in the user info field of a MU-RTS trigger frame should respond with a CTS if they wish to participate in an uplink transmission. When the STAs send their CTS, they use the TA address, the address of the STA (AP) that should receive the CTS. The AP then sends a transmission to initiate uplink transmission from the STAs that appropriately responded. From here, the STAs transmit orthogonal frequency division multiple access (UL OFDMA) TB PPDUs utilizing the allocated resources within the specified 80 MHzbandwidth. After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame. This acknowledgement can be in the form of an 80 MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method. The multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.

[0096] Figure 6C illustrates an example trigger frame downlink (UL) transmission scenario in accordance with some embodiments. It’s similar to the uplink procedure except it facilitates bulk data transmissions from the AP to the STAs rather than from the STAs to the AP. The AP sends to the STAs a multi user RTS, e.g., MU-RTS-TXS for request to send downlink transmissions to the STAs. The process begins with the AP sending a MU RTS TXS trigger frame to the non- AP STA. Upon receiving this frame, the STAs are expected to respond with a CTS frame, indicating that they are ready to receive the data. From here, the AP transmits to the STAs that responded MU PPDUs, which include data intended for the STAs. Finally, the STAs respond with acknowledgement frames back to the AP.

[0097] Figures 7A and 7B show the general structures for EHT (WiFi 7) multi user and trigger based physical layer protocol data unit (PPDU) frames, respectively. (It is expected that the UHR PPDUs will be the same or similar. For simplicity, EHT examples may be used, here, and in other parts of this disclosure, but it should be appreciated that UHR and later specification parameters may equally be implemented.) With reference to Figure 7A, a MU PPDU can be sent to a single user or to multiple users. The frame has legacy (705 A) and contemporary (710A) preamble sections, along with data and packet extension field sections. The legacy section includes a legacy short training field (L-STF), legacy long training field (L-LTF) and a legacy signal field (L-SIG). The contemporary section includes a universal signal field (U-SIG), an EHT signal field (EHT-SIG), an EHT short training field (EHT-STF), an EHT long training field (EHT-LTF), data fields for the actual data payload, and a packet extension (PE) field. The EHT-SIG field, along with the U-SIG field, provides RU (resource unit) allocations and other information the STAs need to understand the MU packet. When the MU PPDU is sent to multiple users, the transmission can be OFDMA or MU-MIMO.

[0098] With reference to Figure 7B, upon receiving a trigger based RTS from an AP, a STA may use the EHT TB PPDU to respond to the trigger from the AP. The EHT TB frame format is similar to the MU PPDU. However, the TB PPDU does not include the EHT-SIG preamble field, and it includes a repeated legacy (RL) signal field in the legacy section. In addition, theEHT-STF field may be two times longer than in the EHT MU PPDU in order to improve performance and reliability for uplink transmissions.

[0099] Figure 7C is a table listing the fields, along with additional information, for a TB PPDU. Figure 7D is a table listing descriptions and information for sub fields in a universal signal (U-SIG) field for either a MU or TB PPDU frame.

[0100] Over the years. The preamble is an important design component used to provide information relevant for the receiver to decode the transmitted data. It is also used to provide backward compatibility with previous PHY versions. However, the preamble has not directly conveyed the PHY version of the packet. Auto detection (or spoofing) mechanisms have been created for receivers to implicitly determine the PHY versions. However, the auto detection algorithms have become more complex. EHT attempts to solve this problem with the universal signal (U-SIG) field. The U-SIG comes after the legacy and RL SIG fields and is 2 OFDM symbols in length. It includes version independent and version dependent bits. The version independent bits are the first 20 bits of the U-SIG and have the same location and definition for EHT and later PHYs. The first 3 bits (bits 0 to 2) are used to identify the PHY version, which simplifies auto detection. The next 3 bits (bits 3 to 5) indicate the spectrum occupancy of the PPDU (e.g., 80 MHz bandwidth). The 7th bit (bit 6) signals the link direction (i.e., uplink or downlink). The next 6 bits (bits 7 to 12) identify the basic service set (BSS) in use via the BSS color and the 7 TXOP bits (bits 13 to 19) provide information on how long the PPDU uses the medium. The U-SIG bits / fields remainder depends on the PHY version and PPDU type.

[0101] To provide flexibility and prepare for possible new capabilities, EHT classifies the reserved bits in the EHT preamble as "disregard" or "validate". This classification helps a receiver determine the appropriate action if it comes across a bit value that is not used in a PHY it supports. Disregard means ignore this bit and continue reception. Validate means check if the bit matches a known value and if not, terminate reception. As an example, values 1 to 7 in the PHY version identifier field will correspond to a future IEEE802.11 PHY version not recognized by a device supporting the current EHT version. If a baseline EHT device receives a value other than 0 (0 indicates EHT PHY), the device should stop reception.

[0102] Wireless network systems can rely on retransmission of media access control (MAC) protocol data units (MPDUs) when the transmitter (TX) does not receive an acknowledgement from the receiver (RX) or MPDUs are not successfully decoded by the receiver. Using an automatic repeat request (ARQ) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU. With requirements of enhanced reliability andreduced latency, the wireless network system can evolve toward a hybrid ARQ (HARQ) approach.

[0103] There are two methods of HARQ processing. In a first type of HARQ scheme, also referred to as chase combining (CC) HARQ (CC-HARQ) scheme, signals to be retransmitted are the same as the signals that previously failed because all subpackets to be retransmitted use the same puncturing pattern. The puncturing is needed to remove some of the parity bits after encoding using an error-correction code. The reason why the same puncturing pattern is used with CC-HARQ is to generate a coded data sequence with forward error correction (FEC) and to make the receiver use a maximum-ratio combining (MRC) to combine the received, retransmitted bits with the same bits from the previous transmission. For example, information sequences are transmitted in packets with a fixed length. At a receiver, error correction and detection are carried out over the whole packet. However, the ARQ scheme may be inefficient in the presence of burst errors. To solve this more efficiently, subpackets are used. In subpacket transmissions, only those subpackets that include errors need to be retransmitted.

[0104] Since the receiver uses both the current and the previously received subpackets for decoding data, the error probability in decoding decreases as the number of used subpackets increases. The decoding process passes a cyclic redundancy check (CRC) and ends when the entire packet is decoded without error or the maximum number of subpackets is reached. In particular, this scheme operates on a stop-and-wait protocol such that if the receiver can decode the packet, it sends an acknowledgement (ACK) to the transmitter. When the transmitter receives an ACK successfully, it terminates the HARQ transmission of the packet. If the receiver cannot decode the packet, it sends a negative acknowledgement (NAK) to the transmitter and the transmitter performs the retransmission process.

[0105] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmitted subpacket. IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. The SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket. Self-decoding is possible when the receiving signal-to-noise ratio (SNR) environment is good (i.e., a high SNR). In some embodiments, subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0106] Multi access point (M-AP) coordination will likely be an important technology in IEEE 802.11 including IEEE 802.1 Ibe and beyond for enhancing reliable channel utilization. M-AP technologies can not only increase spectral efficiency but also can decrease the delay (or latency) of data transmission.

[0107] An AP that obtains a TXOP (transmission opportunity) and can share part or all of it is referred to as a sharing AP. The sharing AP initiates AP coordination to identify an AP candidate by sending a frame (e.g., beacon frame, probe response frame, etc.) that includes the sharing AP’s TXOP capabilities. The AP that wishes to receive the TXOP, after receiving the frame from the sharing AP, is called the shared AP. The sharing AP may also be referred to as a master or a coordinating AP, and the shared AP may also be referred to as a slave or a coordinated AP.

[0108] Various different M-AP technologies have been, and are being, discussed. They include coordinated beamforming (CBF), coordinated spatial reuse (CSR), joint transmission (JTX), and OFDMA / TDMA. Coordinated beam-forming / nulling involves multiple APs transmitting on the same frequency resource based on the coordination and formation of spatial nulls to allow for simultaneous transmission from multiple APs. Interference between the M- APs is reduced through the sharing of channel state information (CSI). With coordinated spatial reuse (C-SR), multiple APs and / or STAs adjust the transmit power to reduce interference between stations (APs, non-AP STA). With joint transmission (JTX) schemes, multiple APs jointly transmit to a given user simultaneously by sharing data between the APs. In effect, the multiple APs act as a single, virtual AP. With coordinated OFDMA / TDMA schemes, M-APs use time and frequency in a cooperative manner to increase system throughput. They transmit on orthogonal frequency resources by coordinating and splitting the spectrum to use it more efficiently.

[0109] Although all of these M-AP technologies have pros and cons, in some embodiments, C-TDMA techniques may be more effective, for example, in terms of fairness. If the data to be transmitted occurs at the devices of the shared AP (i.e., a non TXOP holder), the opportunity to access the channel is relatively high with the C-TDMA compared to other M-AP technologies. In addition, there is no need for feedback channel state information compared to the C- BF / nulling technology, and the implementation is relatively simple compared to the JTX approaches, which require synchronization between APs.

[0110] WiFi implementations (e.g., UHR) permit new methods of TXOP sharing that allow a sharing AP to share its obtained transmission opportunity (TXOP) with other APs, referred to as “shared” APs. In the context of coordinated TDMA (C-TDMA), the AP that has the transmit opportunity (TXOP) to share is referred to as the sharing AP. This AP initiates the AP coordination schemes to determine the AP candidate set by sending a frame, e.g., a management frame such as a Beacon frame or probe response frame, which includes information about the AP coordination scheme capabilities. The AP that participates in the AP coordination schemes after receiving the frame from the sharing AP is called the shared AP. The sharing AP is also known as the master AP or coordinating AP, and the shared AP may be referred to as the slave AP or coordinated AP.

[0111] Figure 8 is a diagram illustrating three BSSs with overlapping areas of coverage. The BSSs include BSS1, BSS2, and BSS3, each with an affiliated AP, API, AP2, and AP3, respectively. With this example, API has two associated non-AP stations (STA1-1, STA1-2); AP2 has two associated non-AP stations (STA2-1, STA2-2), and AP3 has one associated non- AP station (STA3-1), as are indicated in the figure. API is a sharing AP, sharing its TXOP with AP2, which is referred to as the shared AP. AP3 is not directly involved with the TXOP sharing, but it can hear at least some of the transmissions from either or both BSS1 or BSS2. In this capacity, it is referred to as an over-hearing AP. Accordingly, BSS1 is a sharing BSS; BSS2 is a shared BSS and BSS3 is an over-hearing BSS (OBSS).

[0112] In the ultra-high reliability (i.e., UHR, 801.1 Ibn), the concept of TXOP Sharing has been expanded from sharing TXOP within single BSS to sharing TXOP between multiple BSSs (e.g., sharing AP and shared AP(s)). The shared APs can freely exchange frames such as UL / DL within their own BSS during the shared TXOP period. The TXOP duration that the sharing AP shares with the shared AP may be determined in the pre-connection process between the sharing AP and the shared AP, or the sharing AP may allocate an arbitrary TXOP duration to the shared AP. However, there may be cases in which the shared AP cannot fully use the shared TXOP due to unexpected situations. For example, assume the shared AP requests a specific TXOP duration from the sharing AP through a pre-connection phase. In this example, the shared AP requests enough TXOP duration to support an amount of UL / DL PPDU retransmissions. However, when the channel environment is better than expected, transmission / reception of the UL / DL PPDUs can be completed faster than expected. As another example, if the sharing AP arbitrarily allocates the TXOP duration to the shared AP, it may allocate more than what the shared AP needs or can use. With these scenarios, unused TXOP duration (i.e., available TXOP) can leadto waste of resources. To address this issue, a standard method is desired for dealing with available TXOP from an AP’s available transmission opportunity.

[0113] Transferring available TXOP time to other APs is under discussion for UHR (and beyond) to avoid wasting resources when the shared AP cannot fully use the shared TXOP duration. Mechanisms are desired to be able to transfer the available TXOP to another AP, e.g., the sharing AP (original TXOP holder) or even to a different AP, so that the available TXOP can be effectively utilized. For example, if an AP that had shared its TXOP now has a packet that needs to be handled urgently within its own BSS, it may want unused TXOP duration returned to it, or it may want the unused duration to share with other APs. When a sharing AP receives available TXOP from a shared AP, the returned TXOP can be shared with other AP(s) that can make efficient use of the resource. Alternatively, even if the sharing AP does not have a need for the available TXOP, another AP such as an OBSS AP may be able to use it.

[0114] If a sharing AP desires to receive the available TXOP, it should be able to receive it. However, there may not always be a situation where the sharing AP has a need to use the available TXOP. In such cases, other stations should be notified of the available TXOP or at least that the channel is free to have a chance to access it if desired. Accordingly, in some embodiments, a poll frame may be used by an AP to indicate an available TXOP to be shared with one or more other APs. For example, in some embodiments, a poll frame may be used by a shared AP to indicate available remaining TXOP, or it could even be used by a sharing AP to identify one or more shared AP candidates to receive at least a part of a TXOP.

[0115] Figure 9 shows an operational resource sharing scenario between a sharing AP and a shared AP in accordance with some embodiments where a shared AP has remaining TXOP to share. At 905, the sharing AP transmits a Ctrl frame (e.g., MU-RTS TXS) to transfer a TXOP (e.g., at least a portion of a TXOP) with the shared AP. After the shared AP transmits a response frame at 910 (e.g., CTS), it uses the TXOP and transmits or solicits PPDUs (915), e.g., with one or more STAs in its BSS, within the allocated time period and receives an acknowledge frame (920) when the data transfer(s) have completed.

[0116] However, with this example, the shared AP cannot fully use the allocated TXOP duration, and thus, it has available TXOP, e.g., to give back to the sharing AP or to another AP. Accordingly, at 925, the shared AP initiates an indication, e.g., polling frame, to give away its available TXOP duration. The shared AP can return the TXOP to the sharing AP, or it can perform another TXOP Sharing operation with another candidate AP. The Sharing AP may or may not need the TXOP and thus, it would be inefficient for the shared AP to arbitrarily simply return the available TXOP to the sharing AP. Instead, for example, it may be more efficient forthe shared AP to poll other APs, including the sharing AP, to determine whether the TXOP is needed or otherwise can be used by an AP. In some embodiments, the available TXOP indication may give priority to the sharing AP, e.g., through a utilized polling frame. In the following sections, different ways to implement available TXOP indications are discussed.Polling

[0117] In some embodiments, in addition to being used for conventional functions, a poll frame may be used to indicate available TXOP transmission opportunity. A PS-Poll (Power- Save Poll) frame is an example of a polling frame used in WiFi for non-AP stations to retrieve buffered frames from an AP after waking from a power saving mode. In typical implementations, when a STA wishes to enter into a power saving mode, it sends a frame such as a null data frame to the AP with a Power Management bit in the Frame Control field of the null data frame asserted (e.g., set to 1). This indicates to the AP that the STA is transitioning into a power saving state. The AP acknowledges this frame, confirming that it will buffer any frames intended for the STA while it is in the power saving mode. After the STA sends the Null Data frame with the Power Management bit set to 1, the AP starts buffering frames for that STA. The STA can then enter the power saving (e.g., doze) state, conserving power until it wakes up based on a predefined listen interval. The STA periodically wakes up to check for buffered data. It does this by listening for beacon frames from the AP, which include a Traffic Indication Map (TIM) field indicating whether there are frames waiting for the STA. If the STA's AID (Association Identifier) is indicated in the TIM, it knows to wake up and retrieve the buffered frames. If the STA wakes up and detects that there are buffered frames, it sends a PS-Poll frame to the AP to request the data. The PS-Poll frame also includes the STA's AID (e.g., in an AID or Duration / ID field of the PS-Poll frame), allowing the AP to identify the frames to send back. The AP responds with the buffered frames, and the STA remains awake as long as the More Data bit in the frame(s) from the AP is set to 1. Once the STA has received all buffered frames (indicated by the More Data bit being set to 0), it can send another Null Data frame with the Power Management bit set to 1 to signal that it is going back to power saving mode.

[0118] Figure 10 shows the general format for a traditional PS-Poll frame. As shown in the figure, a PS Poll frame includes a Frame Control field, an AID (or Duration / ID) field, a BSS ID (RA) field, a TA field, and an FCS field. The Frame Control field indicates the type of frame. For PS-Poll frames, the frame subtype is set to 1010. The Duration / ID field is used to contain the AID, which is a numeric identifier assigned by the AP to the associated STA. This ID allows the AP to identify which frames are buffered for the waking STA. The BSS ID field includes the BSS identifier of the BSS that the AP is currently associated with. The TA field is thetransmitter address field. This field holds the MAC address of the STA that is sending the PS- Poll frame. Note that a PS-Poll frame does not include a Duration field for updating the network allocation vector (NAV). Instead, stations receiving a PS-Poll frame update their NAV timers based on the short interframe space and the time required to transmit an acknowledgment (ACK) frame.

[0119] A function of the PS-Poll frame in power saving mode is to allow an STA to inform the AP that it can wake up and is ready to receive the frame from the AP. In some embodiments, polling frame (e.g., PS-Poll frame) functionality may be expanded when a TXOP sharing opportunity is being offered for sharing between APs. Such expanded PS-Poll frames may be defined, and used, with a capability of indicating an available TXOP sharing opportunity. In essence, this serves to ask another AP(s) such as a sharing or other AP whether it wants available TXOP, e.g., however obtained but being available such as when an obtained TXOP has been used but TXOP duration is still available.

[0120] Figure 11 A is a diagram showing a frame format for a PS Poll frame with available TXOP indication capabilities in accordance with some embodiments. It includes the same fields (e.g., Frame Control, Duration / ID, BSS-ID, TA, FCS) as with a legacy PS Poll frame. These fields may be used in the same way as with traditional PS Poll operations, but the Duration / ID field can also be used for an AP to indicate that it has available TXOP duration and to indicate the amount of that available duration time.

[0121] In some embodiments, the most significant bit (e.g., bit 15) of the 16 bit field is used to indicate available TXOP duration. With legacy applications, bits 14 and 15 are to be ’ 11 for PS Poll operation, e.g., when a STA awakens and can receive buffered frames from an AP, but a defined state for when bit 15 is 0 is available and may be used to indicate the available TXOP status.

[0122] Figure 1 IB is a table describing the functions of the Duration / ID field based on the values of bits 14 and 15 in accordance with some embodiments. As shown in the table, when the two most significant bits are set to ‘ 11, a receiving station interprets the frame for conventional power state PS-Poll operation. The available 14 lower bits identify the AID value for the awakening / awakened station. It is a unique identifier assigned for the station and ranges from 1 to 2007. It helps the AP identify which buffered frames belong to the waking station.

[0123] On the other hand, when a second AP (e.g., sharing or other AP) receives a PS-Poll frame from a first AP (e.g., shared or other AP) with Bit 15 of the Duration / ID field being ‘0, then it is notified that the first (e.g., shared) AP has available TXOP time that it is offering to make available to another AP. With this example, the amount of available TXOP time isindicated using the lower 15 bits (e.g., B0-B14. When the second (e.g., sharing) AP receives this PS-Poll frame with Bit 15 equal to ‘0 and if the TA field identifies the address of the shared AP that defined a multi-AP sharing operation, when the second AP is a sharing AP, it can implicitly recognize that this is the shared AP to which it had transferred a sharing opportunity and is indicating a available TXOP duration. (Note that in other embodiments, two or more of the bits, e.g., most significant bits, could be used in a poll frame to indicate available-TXOP if more or different functions than simply indicating an available TXOP duration are desired. For example, when bit 15 is ‘0 and depending on the state of bit 14 (‘0 or ‘ 1), an available TXOP polling indication could be a general indication for any AP or a return indication for a sharing AP. This would leave a smaller available range (i.e., 14 bits) for the available TXOP duration but may be warranted, depending on overall performance objectives. In other embodiments, other reserved sub-fields in a PS-Poll frame or in any other polling frame, e.g., encapsulated in any suitable PPDU / MPDU (data, management, and / or control) used for polling may be used to indicate to other APs available TXOP.

[0124] Figure 12 is a diagram showing an operational sequence for a sharing AP responding to a available TXOP duration request frame when it wants to receive the sharing opportunity request in accordance with some embodiments. At 1205, the shared AP transmits an available sharing opportunity (TXOP) indication frame (PS Poll frame in this example). At 1210, the sharing AP responds by transmitting a frame (Self-CTS frame in this example) to indicate that it wants the available TXOP and to cause the OBSS STA(s) to set a basic NAV value. After the Self-CTS frame is transmitted, the associated STAs (not shown) of the sharing AP (and also shared AP) may set an intra BSS NAV, while the OBSS STAs may set a basic NAV value. In this way, the sharing AP and its associated STAs can exchange frames (e.g., UL / DL transmissions) during the transferred available TXOP duration.

[0125] Figure 13 is a diagram showing an operational sequence for a sharing AP responding to an available tXOP duration request frame when it does not want or need the available TXOP duration in accordance with some embodiments. In this example, when the sharing AP does not want the available TXOP from the shared AP, the sharing AP responds to the PS-Poll frame (1305) by transmitting an ACK frame to indicate that it does not want to use the TXOP. When the shared AP receives the ACK frame from the sharing AP, to avoid wasting resources, it can transmit (at 1315) a frame such as a CF-End frame to release the channel, informing OBSS stations that the channel is open.

[0126] Figure 14 is a diagram showing an operational sequence for when a sharing AP does not want to receive the sharing opportunity in accordance with some additional embodiments. Ifthe sharing AP does not want to receive the available TXOP (1405), it may simply transmit nothing back to the shared AP. Not only can this be away for the sharing AP to reject the available TXOP, but also, it can account for situations when the sharing AP cannot hear the available TXOP indication frame (1405) from the shared AP. At 1410, if the shared AP does not hear any response frame from the sharing AP for a specific period of time (e.g., PIFS), at 1415, it can transmit a CF-End frame to inform the stations that the channel is open.

[0127] Figure 15A is a flow diagram showing a method 1500 for a shared AP to indicate it has TXOP duration available in accordance with some embodiments. The method 1500 may be performed by a shared AP as it interacts with a sharing AP or even with a different AP apart from the sharing AP. Either or both APs, for this and / or other methods described in this disclosure, may be implemented by one or more devices described herein such as wireless device 104. Additionally, although shown in a particular order, in some embodiments the operations of the method 1500 (and the other methods shown in the other figures) may be performed in a different order. For example, although the operations of the method 1500 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0128] At 1502, the shared AP sends a frame (e.g., a polling frame) to APs, including the sharing AP, with an indication that it has available TXOP duration to share, e.g., for the sharing or other AP. At 1504, the shared AP determines if the available TXOP is to actually be transferred or otherwise shared, i.e., whether the sharing, or other, AP wants it. If not, then at 1506, the shared AP transmits a notification (e.g., CF-End frame) to notify STAs that the channel is open. On the other hand, if an AP such as the sharing or another AP wants the available TXOP duration, then at 1508, the shared AP sets a NAV (e.g., intra-BSS) value to transfer channel access to the receiving, e.g., sharing, AP. It may perform other or additional frame transfers, as well, to confirm the exchange with the receiving AP.

[0129] Note that at 1504, the shared AP may determine whether an AP such as the sharing AP wants the available shared opportunity in any suitable manner. For example, as shown in the figure, at 1504A, it may wait for an amount of time to determine if an AP will send a response. For example, it could wait to see if an AP sends a response within a period corresponding to a PIFS (Point Coordination Function Interframe Space). In some embodiments, it may give priority to the sharing AP and if it declines or otherwise fails to respond in an amount of time, it may then make the available TXOP duration available to another station. If no response at all is received, then the routine proceeds to 1506 and releases the channel.

[0130] On the other hand, if a response is received, the routine proceeds to 1504B. Here, based on the response, it determines if the available TXOP is to be accepted or rejected by the sharing AP. The response to make this indication by a sharing AP may be any suitable frame including any suitable frame type. In some embodiments, a Self-CTS frame may be used to indicate acceptance, and in some embodiments, an ACK control frame may be used to indicate rejection.

[0131] When a receiving (e.g., sharing) AP wants the available TXOP, a transmitted Self- CTS frame, for example, can cause OBSS station(s) to set an NAV (e.g., basic NAV) value. The Self-CTS frame may also cause the associated STAs of the receiving AP, as well as the TXOP conveying (e.g., shared) to set intra BSS NAV timers. (The other STAs, e.g., OBSS, should set basic NAV values.) In this way, the receiving AP and its associated STAs can exchange frames (e.g., UL / DL) during the available TXOP duration. In some embodiments, if there is sufficient available TXOP duration, the receiving AP, e.g., the sharing AP, could even share the duration with another AP and / or if the sharing AP did not want the available TXOP, the shared AP may share it via a poll indication to other AP(s). Along these lines, in some embodiments, the uses of polling frames, as described herein, may be used by any AP when it has a TXOP available for sharing. That is, a sharing AP could use a polling frame to coordinate TXOP sharing with other APs to set up TXOP sharing with a shared AP prior to the shared AP using it and possibly having available TXOP to share with other APs or return back to a sharing AP.

[0132] Returning to Figure 15 A, at 1504B, based on the response, if the shared AP determines that the available TXOP is to be transferred, the routine goes to 1508 and sets an NAV to avoid contention with the receiving (e.g., sharing) AP. On the other hand, if the response indicates rejection, the routine goes to 1506 and transmits a notice that the channel is available.

[0133] Figure 15B is a flow diagram showing a routine for a receiving AP to process an indication from an AP that it has available TXOP duration in accordance with some embodiments. At 1522, it receives a frame from a first (e.g., shared) AP indicating that the first AP has available TXOP duration available to be conveyed to the receiving (or potentially receiving) AP. For example, the frame could be a polling frame such as a PS Poll frame as discussed above. At 1524, it determines if it wants (e.g., needs or can use) the available TXOP duration. If not, then at 1526, it transmits a frame (e.g., control frame) to the first (e.g., shared) AP to indicate it will not use the available TXOP duration. For example, it could send back an ACK frame. Alternatively, it may send nothing back to the shared AP, implicitly indicating that it will not use the available duration. On the other hand, if the second (receiving) AP wants theavailable TXOP duration, then at 1528, it transmits a frame to indicate acceptance and to keep the channel reserved for the TXOP duration. For example, as discussed above, it could send back a Self-CTS control frame.Examples

[0134] Example l is a method that includes, in a first access point (AP) device, transmitting a polling frame to indicate available sharing opportunity in a channel; determining if the available sharing opportunity is to be transferred to a second AP device; and if the available sharing opportunity is not to be transferred, transmitting a control frame to release the channel.

[0135] Example 2 includes the subject matter of example 1, and comprising setting a network allocation vector (NAV) timer if it is determined that the available sharing opportunity is to be transferred to the second AP device.

[0136] Example 3 includes the subject matter of any of examples 1-2, and wherein the NAV timer is a non intra-basic service set (BSS) NAV timer.

[0137] Example 4 includes the subject matter of any of examples 1-3, and wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

[0138] Example 5 includes the subject matter of any of examples 1-4, and wherein the polling frame is a power save polling (PS-Poll) frame.

[0139] Example 6 includes the subject matter of any of examples 1-5, and wherein the PS- Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

[0140] Example 7 includes the subject matter of any of examples 1-6, and wherein a most significant bit of the Duration / ID field is set to ‘0’ to indicate that the available sharing opportunity is being offered to the second AP device.

[0141] Example 8 includes the subject matter of any of examples 1-7, and wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

[0142] Example 9 includes the subject matter of any of examples 1-8, and wherein determining if the available sharing opportunity is to be transferred to the second AP device includes determining if a response from a sharing AP device is received within an amount of time.

[0143] Example 10 includes the subject matter of any of examples 1-9, and wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

[0144] Example 11 includes the subject matter of any of examples 1-10, and wherein determining if the available sharing opportunity is to be transferred to the second AP deviceincludes determining if the sharing opportunity is to be returned to a sharing AP if a Self clear- to-send (CTS) frame is received from the sharing AP device.

[0145] Example 12 includes the subject matter of any of examples 1-11, and wherein the control frame is a contention free end (CF-End) frame.

[0146] Example 13 is a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of examples 1-12.

[0147] Example 14 is a wireless apparatus that includes a baseband processor; an RF transceiver, and a storage device. The RF transceiver is coupled to the baseband processor. The storage device is coupled to the baseband processor, and includes instructions that when executed by the baseband processor cause it to perform a method as recited in any of examples 1-12.

[0148] Example 15 is a method that includes, in a first access point (AP) device, transmitting a polling frame to indicate an available sharing opportunity in a channel; determining if the available sharing opportunity is to be conveyed to a second AP device; and setting a network allocation vector (NAV) timer if the available sharing opportunity is to be conveyed to the second AP device.

[0149] Example 16 includes the subject matter of example 15, and wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

[0150] Example 17 includes the subject matter of any of examples 15-16, and wherein the polling frame is a power save polling (PS-Poll) frame.

[0151] Example 18 includes the subject matter of any of examples 15-17, and wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

[0152] Example 19 includes the subject matter of any of examples 15-18, and wherein a most significant bit of the Duration / ID field is set to ‘0 to indicate that the available sharing opportunity is being offered to the second AP device.

[0153] Example 20 includes the subject matter of any of examples 15-19, and wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

[0154] Example 21 includes the subject matter of any of examples 15-20, and wherein determining if the available sharing opportunity is to be conveyed to the second AP device includes determining if a response from the second AP device is received within an amount of time.

[0155] Example 22 includes the subject matter of any of examples 15-21, and wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

[0156] Example 23 includes the subject matter of any of examples 15-22, and wherein determining if the available sharing opportunity is to be conveyed to the second AP device includes receiving a Self clear-to-send (CTS) frame from a sharing AP device if the available sharing opportunity is to be returned.

[0157] Example 24 includes the subject matter of any of examples 15-23, and wherein the NAV timer is set responsive to receiving the Self CTS frame.

[0158] Example 25 is a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of examples 15-24.

[0159] Example 26 is a wireless apparatus that includes a baseband processor; an RF transceiver, and a storage device. The RF transceiver is coupled to the baseband processor. The storage device is coupled to the baseband processor, and includes instructions that when executed by the baseband processor cause it to perform a method as recited in any of examples 15-24.

[0160] Example 27 is a method including, in a second access point (AP) device, wirelessly receiving a polling frame over a channel from a first AP device indicating an available sharing opportunity; transmitting a control frame to the first, shared AP device to access the channel if the second AP device will use the available sharing opportunity; and if the second AP device will not use the available sharing opportunity, indicating to the first AP device that the second AP device will not use the available sharing opportunity.

[0161] Example 28 includes the subject matter of example 27, and wherein indicating to the first AP device that the second AP device will not use the available sharing opportunity includes transmitting a different control frame to the first AP device.

[0162] Example 29 includes the subject matter of any of examples 27-28, and wherein the different control frame is an acknowledgement (ACK) frame.

[0163] Example 30 includes the subject matter of any of examples 27-29, and wherein indicating to the first AP device that the second AP device will not use the available sharing opportunity includes not transmitting a response to the polling frame.

[0164] Example 31 includes the subject matter of any of examples 27-30, and wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

[0165] Example 32 includes the subject matter of any of examples 27-31, and wherein the polling frame is a power save polling (PS-Poll) frame.

[0166] Example 33 includes the subject matter of any of examples 27-32, and wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

[0167] Example 34 includes the subject matter of any of examples 27-33, and wherein a most significant bit of the Duration / ID field is set to ‘0 to indicate that the available sharing opportunity is being offered to the second AP device.

[0168] Example 35 includes the subject matter of any of examples 27-34, and wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

[0169] Example 36 includes the subject matter of any of examples 27-35, and wherein the second AP device is a sharing AP device and the first control frame is a Self clear-to-send (CTS) frame.

[0170] Example 37 is a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of examples 27-36.

[0171] Example 38 is a wireless apparatus that includes a baseband processor; an RF transceiver, and a storage device. The RF transceiver is coupled to the baseband processor. The storage device is coupled to the baseband processor, and includes instructions that when executed by the baseband processor cause it to perform a method as recited in any of examples 27-36.

[0172] Example 39 is a method, including: in a shared access point (AP) device, transmitting a first frame to a sharing AP device to indicate an available sharing opportunity duration of a sharing opportunity shared by the sharing AP with the shared AP in a channel; determining if the available sharing opportunity duration is to be returned to the sharing AP device; and if the sharing opportunity duration is not to be returned, transmitting a second frame to release the channel.

[0173] Example 40 is a method that includes the subject matter of example 39, and includes setting a network allocation vector (NAV) timer if it is determined that the available sharing opportunity duration is to be returned to the sharing AP device.

[0174] Example 41 is a method that includes the subject matter of any of examples 39-40, and wherein the NAV timer is a non intra-basic service set (BSS) NAV timer.

[0175] Example 42 is a method that includes the subject matter of any of examples 39-41, and wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

[0176] Example 43 is a method that includes the subject matter of any of examples 39-42, and wherein the first frame is a power save polling (PS-Poll) frame.

[0177] Example 44 is a method that includes the subject matter of any of examples 39-43, and wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered back to the sharing AP device.

[0178] Example 45 is a method that includes the subject matter of any of examples 39-44, and wherein a most significant bit of the Duration / ID field is set to 'O' to indicate that the available sharing opportunity is being offered back to the sharing AP device.

[0179] Example 46 is a method that includes the subject matter of any of examples 39-45, and wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

[0180] Example 47 is a method that includes the subject matter of any of examples 39-46, and wherein determining if the available sharing opportunity duration is to be returned to the sharing AP device includes determining if a response from the sharing AP device is received within an amount of time.

[0181] Example 48 is a method that includes the subject matter of any of examples 39-47, and wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

[0182] Example 49 is a method that includes the subject matter of any of examples 39-48, and wherein determining if the available sharing opportunity duration is to be returned to the sharing AP device includes receiving a Self clear-to-send (CTS) frame from the sharing AP device if the available sharing opportunity duration is to be returned.

[0183] Example 50 is a method that includes the subject matter of any of examples 39-49, and wherein the second frame is a contention free end (CF-End) frame.

[0184] Example 51 is a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform any of the examples as recited in examples 39-50.

[0185] Example 52 is a wireless apparatus including: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of examples 39-50.

[0186] Example 53 is a method, including: in a shared access point (AP) device, transmitting a first frame to a sharing AP device to indicate an available sharing opportunity duration in a channel; determining if the available sharing opportunity duration is to be returned to the sharingAP device; and setting a network allocation vector (NAV) timer if the available sharing opportunity duration is to be returned to the sharing AP device.

[0187] Example 54 is a method that includes the subject matter of example 53, and wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

[0188] Example 55 is a method that includes the subject matter of any of examples 53-54, and wherein the first frame is a power save polling (PS-Poll) frame.

[0189] Example 56 is a method that includes the subject matter of any of examples 53-55, and wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered back to the sharing AP device.

[0190] Example 57 is a method that includes the subject matter of any of examples 53-56, and wherein a most significant bit of the Duration / ID field is set to '0 to indicate that the available sharing opportunity is being offered back to the sharing AP device.

[0191] Example 58 is a method that includes the subject matter of any of examples 53-57, and wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

[0192] Example 59 is a method that includes the subject matter of any of examples 53-58, and wherein determining if the available sharing opportunity duration is to be returned to the sharing AP device includes determining if a response from the sharing AP device is received within an amount of time.

[0193] Example 60 is a method that includes the subject matter of any of examples 53-59, and wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

[0194] Example 61 is a method that includes the subject matter of any of examples 53-60, and wherein determining if the available sharing opportunity duration is to be returned to the sharing AP device includes receiving a Self clear-to-send (CTS) frame from the sharing AP device if the available sharing opportunity duration is to be returned.

[0195] Example 62 is a method that includes the subject matter of any of examples 53-61, and wherein the NAV timer is set responsive to receiving the Self CTS frame.

[0196] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein may be or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one ormore data processing components (generically referred to here as a “processor” or “processing unit”) to perform the operations described herein. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines). Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0197] In some cases, an embodiment may be an apparatus (e.g., an AP STA, a non-AP STA, or another network or computing device) that includes one or more hardware and software logic structures for performing one or more of the operations described herein. For example, as described herein, an apparatus may include a memory unit, which stores instructions that may be executed by a hardware processor installed in the apparatus. The apparatus may also include one or more other hardware or software elements, including a network interface, a display device, etc.

[0198] Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consi stent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

[0199] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

[0200] The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general -purpose computer selectively activated or reconfigured by a computer program stored in the computer. For example, a computer system or other data processing system may carry outthe computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

[0201] The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general -purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

[0202] The present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). In some embodiments, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory components, etc.

[0203] In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Claims

CLAIMSWhat is claimed is:

1. A method, comprising: in a first access point (AP) device, transmitting a polling frame to indicate an available sharing opportunity in a channel; determining if the available sharing opportunity is to be transferred to a second AP device; and if the available sharing opportunity is not to be transferred, transmitting a different frame to release the channel.

2. The method of claim 1, comprising setting a network allocation vector (NAV) timer if it is determined that the available sharing opportunity is to be transferred to the second AP device.

3. The method of claim 2, wherein the NAV timer is an intra-basic service set (BSS) NAV timer.

4. The method of claim 1, wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

5. The method of claim 1, wherein the polling frame is a power save polling (PS-Poll) frame.

6. The method of claim 5, wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

7. The method of claim 6, wherein a most significant bit of the Duration / ID field is set to ‘0’ to indicate that the available sharing opportunity is being offered to the second AP device.

8. The method of claim 7, wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

9. The method of claim 1, wherein determining if the available sharing opportunity is to be transferred to the second AP device includes determining if a response from the second AP device is received within an amount of time.

10. The method of claim 9, wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

11. The method of claim 1, wherein determining if the available sharing opportunity is to be transferred to the second AP device includes determining if the sharing opportunity is to be returned to a sharing AP if a Self clear-to-send (CTS) frame is received from the sharing AP device.

12. The method of claim 1, wherein the different frame is a contention free end (CF-End) frame.

13. A non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of claims 1-12.

14. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 1-12.

15. A method, comprising: in a first access point (AP) device, transmitting a polling frame to indicate an available sharing opportunity in a channel; determining if the available sharing opportunity is to be conveyed to a second AP device; and setting a network allocation vector (NAV) timer if the available sharing opportunity is to be conveyed to the second AP device.

16. The method of claim 15, wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

17. The method of claim 15, wherein the polling frame is a power save polling (PS-Poll) frame.

18. The method of claim 17, wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

19. The method of claim 18, wherein a most significant bit of the Duration / ID field is set to ‘0 to indicate that the available sharing opportunity is being offered to the second AP device.

20. The method of claim 19, wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

21. The method of claim 15, wherein determining if the available sharing opportunity is to be conveyed to the second AP device includes determining if a response from the second AP device is received within an amount of time.

22. The method of claim 21, wherein the amount of time corresponds to a point coordination function interframe space (PIFS).

23. The method of claim 15, wherein determining if the available sharing opportunity is to be conveyed to the second AP device includes receiving a Self clear-to-send (CTS) frame from a sharing AP device if the available sharing opportunity is to be conveyed.

24. The method of claim 23, wherein the NAV timer is set responsive to receiving the Self CTS frame.

25. A non-transitory machine readable medium having instructions that when executed perform a method as recited in any of claims 15-24.

26. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 15-24.

27. A method, comprising: in a second access point (AP) device, wirelessly receiving a polling frame over a channel from a first AP device indicating an available sharing opportunity;transmitting a first frame to the first AP device to access the channel if the second AP device will use the available sharing opportunity; and if the second AP device will not use the available sharing opportunity, indicating to the first AP device that the second AP device will not use the available sharing opportunity.

28. The method of claim 27, wherein indicating to the first AP device that the second AP device will not use the available sharing opportunity includes transmitting a different frame to the first AP device.

29. The method of claim 28, wherein the different frame is an acknowledgement (ACK) frame.

30. The method of claim 27, wherein indicating to the first AP device that the second AP device will not use the available sharing opportunity includes not transmitting a response to the polling frame.

31. The method of claim 27, wherein the sharing opportunity is a transmission opportunity (TXOP) sharing opportunity.

32. The method of claim 27, wherein the polling frame is a power save polling (PS-Poll) frame.

33. The method of claim 32, wherein the PS-Poll frame includes a Duration / ID field with at least one bit value to indicate that the available sharing opportunity is being offered to the second AP device.

34. The method of claim 33, wherein a most significant bit of the Duration / ID field is set to ‘0 to indicate that the available sharing opportunity is being offered to the second AP device.

35. The method of claim 34, wherein the Duration / ID field includes a plurality of least significant bits to indicate an amount of available sharing opportunity duration.

36. The method of claim 27, wherein the second AP device is a sharing AP device and the first frame is a Self clear-to-send (CTS) frame.

37. A non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of claims 27-36.

8. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 27-36.

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