EP4684578A2 - Enhanced transmit opportunity sharing with coordinated-time division multiple access transmission - Google Patents

Abstract

An enhanced MU-RTS TXS trigger frame to enable efficient C-TDMA mechanisms between APs. The enhanced frame addresses the challenges faced in implementing C-TDMA schemes in high-density network scenarios beyond IEEE 802.11be, such as wasted resources due to allocated TXOP sharing time and unintentional NAV setting at STAs associated with the shared AP. The enhanced MU-RTS TXS trigger frame allows an AP to allocate a portion of its obtained TXOP to other APs, mitigates the issue of wasted resources, and provides a means to manage the basic NAV set by the sharing AP at the STAs associated with the shared AP. The frame is applicable to other Multi-AP schemes, handling NAV issues from other BSS. It also enables a shared AP to return unused shared allocation time to the sharing AP, allowing the sharing AP to resume normal PPDU transmissions earlier in the remaining TXOP, ultimately increasing system throughput.

Description

ENHANCED TRANSMIT OPPORTUNITY SHARING WITH COORDINATED-TIME

DIVISION MULTIPLE ACCESS TRANSMISSION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Nos. 63/502,632 filed May 16, 2023 and 63/504,402 filed May 25, 2023, the entire contents of each of which is hereby incorporated by reference.

TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to enhanced transmit opportunity sharing with coordinated-time division multiple access transmission.

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 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 the latest 802.1 lax (also known as “Wi-Fi 6”). These standards specify the modulation techniques, channel bandwidths, and other technical aspects that ensure 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.

[0004] IEEE 802.1 Ibe, also known as “Wi-Fi 7”, is the next generation of the IEEE 802.11 family of standards for wireless local area networks. Currently under development, 802.1 Ibe aims to significantly improve upon the capabilities of its predecessor, 802.1 lax/Wi-Fi 6, by offering even higher data rates, lower latency, and increased reliability. The standard is expected to leverage advanced technologies such as multi-link operation (MLO), which allows devices to simultaneously use multiple frequency bands and channels for enhanced performance and reliability. Additionally, 802.1 Ibe will introduce 4096-QAM (Quadrature Amplitude Modulation), enabling higher data rates by encoding more bits per symbol. The standard will also feature improved medium access control (MAC) efficiency, enhanced power saving capabilities, and better support for high-density environments. With these advancements, 802.1 Ibe is expected to deliver theoretical maximum data rates of up to 46 gigabits per second (Gbps), making it suitable for bandwidth-intensive applications such as virtual and augmented reality, 8K video streaming, and high-performance gaming. The IEEE 802.1 Ibe standard is projected to be finalized by the end of 2024, paving the way for the next generation of Wi-Fi devices and networks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] 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.

[0006] FIG. 1 illustrates an example of a wireless local area network with a basic service set that includes multiple wireless devices, in accordance with some embodiments of the present disclosure.

[0007] FIG. 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

[0008] FIG. 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.

[0009] FIG. 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.

[0010] FIG. 4 illustrates inter-frame space relationships, in accordance with some embodiments of the present disclosure.

[0011] FIG. 5 illustrates a carrier sense multiple access/collision avoidance-based frame transmission procedure, in accordance with some embodiments of the present disclosure. [0012] FIG. 6 is a table of various characteristics of several wireless networking standards, in accordance with some embodiments of the present disclosure.

[0013] FIG. 7 is a table of various fields of an extremely high throughput physical protocol data unit frame, in accordance with some embodiments of the present disclosure.

[0014] FIG. 8 illustrates an example of the user info field in the enhanced MU-RTS TXS Trigger frame, in accordance with some embodiments of the present disclosure.

[0015] FIG. 9 illustrates the encoding of the Triggered TXOP Sharing Mode subfield in the 802.1 Ibe standard, in accordance with some embodiments of the present disclosure. [0016] FIG. 10 illustrates an example of a possible encoding of the Triggered TXOP Sharing Mode subfield in the Ultra High Reliability (UHR) or future IEEE 802.11 standard, in accordance with some embodiments of the present disclosure.

[0017] FIG. 11 illustrates an example topology of multiple APs and STAs for Coordinated Time Division Multiple Access (C-TDMA), in accordance with some embodiments of the present disclosure.

[0018] FIG. 12 illustrates an example snapshot of the Network Allocation Vector (NAV) when enhanced MU-RTS TXS/CTS frames are exchanged between APs to perform C-TDMA, in accordance with some embodiments of the present disclosure.

[0019] FIG. 13 illustrates an example snapshot of the NAV setting when enhanced MU-RTS TXS/CTS frames are exchanged to perform C-TDMA using the proposed scheme, in accordance with some embodiments of the present disclosure.

[0020] FIG. 14 illustrates an example of the field location of the enhanced MU-RTS TXS frame with the Bound field in the SIG field, in accordance with some embodiments of the present disclosure.

[0021] FIG. 15 illustrates an example of the field location of the enhanced MU-RTS TXS frame with the Bound field in the common info field, in accordance with some embodiments of the present disclosure.

[0022] FIG. 16 illustrates an example of the field location of the enhanced MU-RTS TXS frame with the Bound field in the user info field, in accordance with some embodiments of the present disclosure.

[0023] FIG. 17 illustrates an example of a frame exchange sequence, in accordance with some embodiments of the present disclosure.

[0024] FIG. 18 illustrates an example of the Group BSS color in the enhanced MU-RTS TXS frame with the Group BSS color in the SIG field, in accordance with some embodiments of the present disclosure.

[0025] FIG. 19 illustrates an example of the Group BSS color in the enhanced MU-RTS TXS frame with the Group BSS color in the common info field, in accordance with some embodiments of the present disclosure.

[0026] FIG. 20 illustrates an example of the Group BSS color in the enhanced MU-RTS TXS frame with the Group BSS color in the user info field, in accordance with some embodiments of the present disclosure. [0027] FIG. 21 illustrates an example of a frame exchange procedure in terms of the prepare phase, C-TDMA setup/Data & Ack, and after C-TDMA, where AP2 cascades allocation time to an associated STA, in accordance with some embodiments of the present disclosure.

[0028] FIG. 22 illustrates an example of a frame exchange procedure in terms of the prepare phase, C-TDMA setup/Data & Ack, and after C-TDMA, where AP2 uses allocation time for downlink service to an associated STA, in accordance with some embodiments of the present disclosure.

[0029] FIG. 23 illustrates an example of a frame exchange procedure in terms of the prepare phase, C-TDMA setup/Data & Ack, and after C-TDMA, where AP2 uses allocation time to receive uplink data from associated STAs, in accordance with some embodiments of the present disclosure.

[0030] FIG. 24 illustrates an example topology of Overlapping Basic Service Sets (OBSS) and multiple APs to perform C-TDMA, in accordance with some embodiments of the present disclosure.

[0031] FIG. 25 illustrates an example snapshot of the NAV setting when OBSS exchanges MU-RTS/CTS control frames, in accordance with some embodiments of the present disclosure. [0032] FIG. 26 illustrates an example snapshot of the NAV setting in both OBSS and Multi- APs scenarios to perform C-TDMA, in accordance with some embodiments of the present disclosure.

[0033] FIG. 27 illustrates an example snapshot of the NAV setting when applying the disclosed solution, in accordance with some embodiments of the present disclosure.

[0034] FIG. 28 illustrates an example of a frame exchange procedure in an OBSS and Multi- AP (M-AP) topology, in accordance with some embodiments of the present disclosure.

[0035] FIG. 29 illustrates an example of the return of the shared AP's allocation time to the sharing AP using the Enhanced MU-RTS TXS frame, in accordance with some embodiments of the present disclosure.

[0036] FIG. 30 illustrates a method for a sharing access point in a wireless network to allocate a portion of its transmit opportunity to a shared access point by generating and wirelessly transmitting a trigger frame, in accordance with some embodiments of the present disclosure. [0037] FIG. 31 illustrates a method for a station associated with a sharing access point to receive a trigger frame indicating a transmit opportunity allocation to a shared access point, defer its uplink transmission until the allocated portion ends, and then wirelessly transmit the uplink data to the sharing access point, in accordance with some embodiments of the present disclosure. [0038] FIG. 32 illustrates a method for a shared access point to receive a trigger frame allocating a transmit opportunity portion from a sharing access point, determine the unused residual time, and generate and transmit a second trigger frame to return the unused portion back to the sharing access point, in accordance with some embodiments of the present disclosure.

[0039] FIG. 33 illustrates a method for a shared access point to receive a trigger frame allocating a transmit opportunity portion from a sharing access point, determine the unused residual time, and generate and transmit a second trigger frame to return the unused portion back to the sharing access point, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

[0040] The present disclosure generally relates to wireless communications, and more specifically, relates to enhanced transmit opportunity sharing with coordinated-time division multiple access transmission.

[0041] The current IEEE 802.11 standard faces challenges in efficiently implementing Coordinated-Time Division Multiple Access (C-TDMA) schemes in high-density network scenarios. When Access Points (APs) participate in C-TDMA, they require a mechanism to share information and solicit C-TDMA between APs. Additionally, there is a need to efficiently handle the unused time allocated to the shared AP and return it to the sharing AP. Another issue arises from the unintentional Network Allocation Vector (NAV) setting at the stations (STAs) associated with the shared AP. This unintentional NAV setting can lead to inefficient utilization of the shared TXOP (Transmit Opportunity) and hinder the overall system throughput.

Addressing these challenges could enhance spectral efficiency and maximize the benefits of C- TDMA in high-density network environments beyond the current IEEE 802.1 Ibe standard. [0042] To address the challenges faced in implementing Coordinated-Time Division Multiple Access (C-TDMA) schemes in high-density network scenarios beyond IEEE 802.1 Ibe, disclosed techniques introduce an enhanced Multi-User Request-to-Send Transmit Opportunity Sharing (MU-RTS TXS) trigger frame. This enhanced trigger frame enables efficient C-TDMA mechanisms between APs, allowing an AP to allocate a portion of its obtained TXOP (Transmit Opportunity) to other APs. By utilizing the enhanced MU-RTS TXS trigger frame, the issue of wasted resources due to allocated TXOP sharing time can be mitigated.

[0043] The proposed trigger frame also addresses the problem of unintentional Network Allocation Vector (NAV) setting at the stations (STAs) associated with the shared AP. It provides a means to manage the basic NAV set by the sharing AP at the STAs associated with the shared AP, ensuring efficient utilization of the shared TXOP. [0044] Moreover, the enhanced MU-RTS TXS trigger frame is not limited to C-TDMA but can also be applied to other Multi-AP schemes, effectively handling NAV issues from other Basic Service Sets (BSS).

[0045] Additionally, the proposed trigger frame allows a shared AP to return any unused portion of the shared allocation time to the sharing AP. This enables the sharing AP to resume its normal PPDU (Physical Layer Protocol Data Unit) transmissions earlier in the remaining TXOP, leading to increased system throughput.

[0046] In an embodiment, a method is performed by a wireless device functioning as a sharing access point (AP) in a wireless network comprises. In a first step, the sharing AP generates a trigger frame. The purpose of this trigger frame is to allocate a portion of the sharing AP's transmit opportunity (TXOP) to another AP in the wireless network, referred to as the shared AP. The TXOP represents a time duration during which an AP has the right to initiate wireless transmissions. By generating the trigger frame, the sharing AP prepares to grant a specific time period within its own TXOP to the shared AP. This allows the shared AP to utilize a designated portion of the sharing AP's transmission time.

[0047] In a second step, the sharing AP wirelessly transmits the generated trigger frame to the shared AP. The transmission of the trigger frame serves as a notification and allocation mechanism, informing the shared AP about the portion of the TXOP that has been allocated to it.

[0048] Upon receiving the trigger frame, the shared AP becomes aware of the time duration it has been granted within the sharing AP's TXOP. This enables the shared AP to plan and initiate its own wireless transmissions during the allocated time period.

[0049] The method facilitates efficient utilization of transmission opportunities in a wireless network by allowing a sharing AP to allocate a portion of its TXOP to a shared AP. This mechanism promotes collaboration and coordination among APs, leading to improved network performance and resource utilization.

[0050] In an embodiment, a method is performed by a wireless device operating as a station (STA) associated with a sharing access point (AP) in a wireless network. In a first step, the STA receives a trigger frame sent by the sharing AP. The trigger frame serves the purpose of allocating a portion of the sharing AP's transmit opportunity (TXOP) to another AP in the wireless network, referred to as the shared AP. The trigger frame includes information about the allocation duration, indicating the time period within the sharing AP's TXOP that is being allocated to the shared AP. [0051] Upon receiving the trigger frame, the STA becomes aware of the portion of the TXOP that the sharing AP has allocated to the shared AP.

[0052] In a second step, the STA determines to defer its own uplink data transmission to the sharing AP until after the allocated portion of the TXOP for the shared AP has ended. This means that the STA will wait and not initiate its uplink transmission to the sharing AP during the time period that has been allocated to the shared AP.

[0053] By deferring its uplink transmission, the STA avoids interfering with the wireless transmissions of the shared AP during its allocated TXOP portion.

[0054] In a third step, after the portion of the TXOP allocated to the shared AP has ended, the STA wirelessly transmits its uplink data transmission to the sharing AP. This step takes place once the shared AP's allocated time period within the sharing AP's TXOP has concluded.

[0055] By waiting until the shared AP's allocated TXOP portion is over, the STA ensures that its uplink transmission to the sharing AP does not overlap or interfere with the wireless transmissions of the shared AP.

[0056] The method enables efficient coordination and coexistence of wireless transmissions between the sharing AP, the shared AP, and the associated STAs in a wireless network. By deferring uplink transmissions during the allocated TXOP portion for the shared AP, the STA helps to minimize interference and promote fair access to the wireless medium.

[0057] In an embodiment, a method is performed by a wireless device functioning as a station (STA) associated with a shared access point (AP) in a wireless network. In a first step, the STA receives a trigger frame sent by a sharing AP in the wireless network. The purpose of the trigger frame is to allocate a portion of the sharing AP's transmit opportunity (TXOP) to the shared AP with which the STA is associated. The trigger frame serves as a notification and allocation mechanism, informing the shared AP about the portion of the TXOP that has been allocated to it by the sharing AP.

[0058] Upon receiving the trigger frame, the STA becomes aware of the allocation of the TXOP portion from the sharing AP to its associated shared AP.

[0059] In a second step, the STA takes action to prevent itself from setting a basic network allocation vector (NAV). The basic NAV is a mechanism used in wireless networks to indicate the duration for which the wireless medium is expected to be busy, and during this time, STAs typically refrain from initiating transmissions.

[0060] However, in this case, by preventing the setting of the basic NAV, the STA ensures that it is not restricted from transmitting uplink data to its associated shared AP during the portion of the TXOP allocated to the shared AP. [0061] By not setting the basic NAV, the STA allows itself to initiate uplink transmissions to the shared AP even during the time period that has been allocated to the shared AP by the sharing AP. This enables the STA to efficiently utilize the allocated TXOP portion for communication with its associated shared AP.

[0062] The method promotes efficient utilization of the allocated TXOP portion by allowing the STA to transmit uplink data to its associated shared AP without being restricted by the basic NAV. This approach optimizes the use of the wireless medium and enhances the communication performance between the STA and the shared AP during the allocated TXOP portion.

[0063] In an embodiment, a method is performed by a shared access point (AP) in a wireless network. In a first step, the shared AP receives a first trigger frame sent by a sharing AP in the wireless network. The purpose of the first trigger frame is to allocate a portion of the sharing AP's transmit opportunity (TXOP) to the shared AP. The first trigger frame includes information about the allocation duration, indicating the time period within the sharing AP's TXOP that is being allocated to the shared AP.

[0064] Upon receiving the first trigger frame, the shared AP becomes aware of the portion of the TXOP that has been allocated to it by the sharing AP.

[0065] In a second step, the shared AP determines a residual time, which represents the remaining unused portion of the allocated TXOP portion. This residual time reflects the time duration within the allocated TXOP that the shared AP did not utilize for its own transmissions.

[0066] In a third step, the shared AP generates a second trigger frame. The purpose of the second trigger frame is to return the remaining unused portion of the allocated TXOP back to the sharing AP. The second trigger frame includes information about the residual time, indicating the duration of the unused TXOP portion that the shared AP is returning to the sharing AP.

[0067] In a fourth step, the shared AP wirelessly transmits the second trigger frame to the sharing AP. By sending this second trigger frame, the shared AP effectively returns the remaining unused portion of the allocated TXOP back to the sharing AP.

[0068] The method enables efficient utilization of the allocated TXOP by allowing the shared AP to return any unused portion of the allocated TXOP back to the sharing AP. This mechanism ensures that the unused TXOP is not wasted and can be utilized by the sharing AP or other APs in the wireless network.

[0069] By dynamically returning the unused TXOP portion, the shared AP helps to optimize the overall utilization of the wireless medium and promotes efficient resource allocation in the wireless network. [0070] For sake of illustration, various embodiments are primarily described herein in the context of wireless networks based on Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards using terminology thereof. However, embodiments are not limited thereto. Those skilled in the relevant art will appreciate that the techniques disclosed herein can be used in other types of wireless networks.

[0071] In the following detailed description, only 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, all without departing from the 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.

[0072] FIG. 1 depicts a wireless local area network 100 (WLAN 100) with a basic service set (BSS) 102. The BSS 102 comprises multiple wireless devices 104 (also known as WLAN devices 104). Each wireless device 104 is equipped with a medium access control (MAC) layer and a physical (PHY) layer, conforming to the IEEE 802.11 standard, which may include any of its amendments (e.g., 802.11a/b/g/n/p/ac/ax/bd/be and beyond).

[0073] In one embodiment, the medium access control (MAC) layer of a wireless device 104 can initiate the transmission of a frame to another wireless device 104 by passing a PHY- TXSTART. request (TXVECTOR) to the physical (PHY) layer. The TXVECTOR specifies parameters for generating and/or transmitting the corresponding frame. Likewise, the PHY layer of a receiving wireless device can generate an RXVECTOR, which includes parameters of the received frame, and pass it to the MAC layer for processing.

[0074] The group of wireless devices 104 may include a wireless device 104 A that serves as an access point, sometimes referred to as an “access point station” or “AP STA,” and other wireless devices 104B1-104B4 that function as non-access point stations, often called “non-AP STAs.”

[0075] Alternatively, in an ad-hoc networking environment, all devices in the group, 104, might be non-access point stations. Typically, both the access point station (e.g., wireless device 104 A) and the non-access point stations (e.g., wireless devices 104B1-104B4) are collectively considered stations. However, for simplicity in this description, the term “station” may sometimes only refer to non-access point stations. While this example shows four non-access point stations (wireless devices 104B-1 through 104B-4), the wireless local area network (WLAN) 100 can accommodate any number of non-access point stations (e.g., one or more wireless devices 104B). [0076] FIG. 2 presents a schematic block diagram of a wireless device 104, according to an embodiment. This wireless device 104 could be either the wireless device 104A (e.g., the access point of wireless local area network (WLAN) 100) or any of the wireless devices 104B-lthrough 104B-4 depicted in FIG. 1. The wireless device 104 comprises a baseband processor 210, a radio frequency (RF) transceiver 240 (RF transceiver 240), an antenna unit 250, a storage device (e.g., memory) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the input interfaces 234, the output interfaces 236, and the RF transceiver 240 are interconnected via a bus 260.

[0077] The baseband processor 210 is responsible for baseband signal processing and encompasses a medium access control (MAC) processor 212 (MAC processor 212) and a physical (PHY) processor 222 (PHY processor 222). It may access memory 232, which can be a non-transitory computer-readable medium containing software (e.g., programmable instructions) and data.

[0078] In an embodiment, the MAC processor 212 comprises a MAC software processing unit 214 and a MAC hardware processing unit 216. The MAC software processing unit 214 executes MAC software to perform a first set of functions of the MAC layer, which can be part of the software stored in storage device 232. Conversely, the MAC hardware processing unit 216 realizes a second set of MAC layer functions through specialized hardware. However, the configuration of the MAC processor 212 is not limited to these arrangements. For instance, it may be designed to execute both sets of functions entirely in software or entirely in hardware, depending on the specific implementation.

[0079] The PHY processor 222 comprises a transmitting (TX) signal processing unit (SPU) 224 (TxSPU 224) and a receiving (RX) SPU 226 (RxSPU 226). It executes a variety of functions associated with the physical (PHY) layer, which can be carried out in software, hardware, or a mix of both, depending on the implementation.

[0080] Functions performed by the TxSPU 224 may include, but are not limited to, forward error correction (FEC) encoding, parsing streams into one or more spatial streams, diversity encoding of these spatial streams into a multitude of space-time streams, spatial mapping of space-time streams to transmit chains, inverse Fourier transform computation, and cyclic prefix insertion to establish a guard interval. Conversely, the RxSPU 226 may handle functions that are essentially the inverses of those performed by the TxSPU 224, such as guard interval removal, Fourier transform computation, among others.

[0081] The RF transceiver 240 comprises an RF transmitter 242 and an RF receiver 244. It is designed to transmit information (referred to as first information) received from the baseband processor 210 to the wireless local area network (WLAN) 100 (for example, to another wireless device 104 within the WLAN 100) and to relay information (referred to as second information) received from the WLAN 100 (for example, from another wireless device 104 of the WLAN 100) back to the baseband processor 210.

[0082] The antenna unit 250 comprises one or more antennas. For applications utilizing multiple-input, multiple-output (MIMO) or multi-user multiple-input, multiple-output (MU- MIMO), the antenna unit 250 may feature a plurality of antennas. In certain embodiments, these antennas can function as part of a beamforming array. Additionally, the antennas within the antenna unit 250 can be either directional, with options for fixed or steerable orientations.

[0083] Input interfaces 234 receive information from a user, while the output interfaces 236 convey information to the user. The input interfaces 234 may consist of one or more of the following: a keyboard, keypad, mouse, touchscreen, microphone, among others. Similarly, the output interfaces 236 may include one or more of the following: a display device, touchscreen, speaker, among others.

[0084] As outlined in this document, numerous functions of the wireless local area network (WLAN) device 104 can be realized through either hardware or software. The decision to implement certain functions in software and others in hardware is influenced by various design constraints. These constraints may encompass aspects such as design and manufacturing costs, time-to-market objectives, power consumption considerations, and the availability of semiconductor technology, among others.

[0085] 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 wireless local area network (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. [0086] FIG. 3 A illustrates components of a wireless local area network (WLAN) device 104 configured to transmit data according to an embodiment, including a transmitting (TX) signal processing unit (SPU) 324 (TxSPU 324), a radio frequency (RF) transmitter 342 (RF transmitter 342), and an antenna 352. In an embodiment, the TxSPU 324, the RF transmitter 342, and the antenna 352 correspond to the TxSPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of FIG. 2, respectively.

[0087] The TxSPU 324 comprises an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer 306, and a guard interval inserter 308. [0088] Encoder 300 receives input data and encodes it. In one embodiment, the encoder 300 features a forward error correction (FEC) encoder, which may consist of a binary convolutional code encoder followed by a puncturing device. Alternatively, the FEC encoder may utilize a low-density parity-check encoder.

[0089] The TxSP 324 may also incorporate a scrambler to scramble the input data before encoding by the encoder 300, aiming to minimize the likelihood of prolonged sequences of 0s or Is. When binary convolutional code encoding is executed by the encoder 300, the TxSP 324 might include an encoder parser to demultiplex the scrambled bits across multiple binary convolutional code encoders. However, if the encoder utilizes low-density parity-check encoding, the TxSP 324 may forego the use of the encoder parser.

[0090] The interleaver 302 interleaves the bits of each stream output from the encoder 300, altering their order. The interleaver 302 applies interleaving specifically when the encoder 300 performs binary convolutional code encoding. In cases where binary convolutional code encoding is not used, it may pass the stream output from the encoder 300 without modifying the bit order.

[0091] Mapper 304 converts the sequence of bits output from the interleaver 302 into constellation points. When the encoder 300 uses low-density parity-check encoding, the mapper 304 may additionally execute low-density parity-check tone mapping, alongside constellation mapping.

[0092] When the TxSP 324 is engaged in multiple-input, multiple-output (MIMO) or multiuser multiple-input, multiple-output (MU-MIMO) transmissions, it may incorporate multiple interleavers 302 and mappers 304, corresponding to the number of spatial streams involved in the transmission. Additionally, the TxSP 324 might feature a stream parser to segment the encoder 300's output into blocks, which are then distributed to different interleavers 302 or mappers 304. It may also include a space-time block code encoder to disperse the constellation points across the spatial streams into a set number of space-time streams, and a spatial mapper tasked with assigning these space-time streams to transmit chains. This spatial mapper could employ strategies such as direct mapping, spatial expansion, or beamforming for optimal transmission.

[0093] The inverse Fourier transform 306 transforms a block of constellation points, received from the mapper 304 or, in cases of multiple-input, multiple-output (MIMO) or multi-user multiple-input, multiple-output (MU-MIMO), the spatial mapper, into a time domain block (e.g., a symbol) through an inverse discrete Fourier transform or an inverse fast Fourier transform. When employing the space-time block code encoder and the spatial mapper, a dedicated inverse Fourier transform 306 may be provided for each transmit chain.

[0094] When conducting a multiple-input, multiple-output (MIMO) or multi-user multipleinput, multiple-output (MU-MIMO) transmission, the TxSP 324 may incorporate cyclic shift diversities to avert unintended beamforming. The cyclic shift diversities insertion can occur either before or after the inverse Fourier transform 306 process. It can be applied specifically for each transmit chain or for each space-time stream. Alternatively, cyclic shift diversities may be integrated as part of the spatial mapping process.

[0095] In multiple-input, multiple-output (MIMO) or multi-user multiple-input, multipleoutput (MU-MIMO) transmissions conducted by the TxSP 324, specific blocks preceding the spatial mapper are allocated individually for each user.

[0096] The guard interval inserter 308 appends a guard interval to the beginning of each symbol output by the inverse Fourier transform 306. This guard interval typically comprises a cyclic prefix, which is a duplicate of the symbol's concluding segment, placed before the symbol to mitigate interference. Optionally, the TxSP 324 can apply windowing to each symbol postguard interval insertion to smooth out the symbol edges.

[0097] The RF transmitter 342 converts the baseband symbols into a radio frequency (RF) signal and then transmits this RF signal through antenna 352. In cases where the TxSP 324 supports multiple-input, multiple-output (MIMO) or multi-user multiple-input, multiple-output (MU-MIMO) transmissions, both the guard interval inserter 308 and the RF transmitter 342 are configured for each individual transmit chain.

[0098] FIG. 3B illustrates components of a wireless local area network (WLAN) device 104 configured to receive data, including a receiver signal processing unit 326 (RxSPU 326), a radio frequency (RF) receiver 344 (RF receiver 344), and an antenna 354. In this embodiment, the RxSPU 326, RF receiver 344, and antenna 354 correspond to the receiving SPU 226, the RF receiver 244, and one of the antennas in the antenna unit 250 of FIG. 2, respectively.

[0099] The RxSPU 326 includes a guard interval remover 318, a Fourier transformer 316 (FT 316), a demapper 314, a deinterleaver 312, and a decoder 310.

[0100] The RF receiver 344 receives a radio frequency (RF) signal via the antenna 354 and converts the RF signal into symbols. The guard interval remover 318 then removes the guard interval from each symbol. When the received transmission employs multiple-input, multipleoutput (MIMO) or multi-user multiple-input, multiple-output (MU-MIMO) technology, the RF receiver 344 and the guard interval remover 318 may be allocated for each receive chain. [0101] The FT 316 converts each symbol (e.g., each time domain block) into a frequency domain block of constellation points using either a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). FT 316 may be allocated for each receive chain.

[0102] When the received transmission is a multiple-input, multiple-output (MIMO) or multiuser multiple-input, multiple-output (MU-MIMO) transmission, the RxSP 326 may include a spatial demapper that converts the outputs of the FTs 316 from the receiver chains into constellation points of multiple space-time streams. Additionally, a space-time block code decoder may be employed for despreading the constellation points from the space-time streams into one or more spatial streams.

[0103] The demapper 314 demaps the constellation points output from the FT 316 or the spacetime block code decoder to bit streams. If the received transmission was encoded using low- density parity-check encoding, demapper 314 may further perform low-density parity-check tone demapping before performing the constellation demapping.

[0104] The deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314. It performs deinterleaving specifically when the received transmission was encoded with binary convolutional code encoding. Otherwise, it may pass the stream from demapper 314 without any deinterleaving.

[0105] When the received transmission employs multiple-input, multiple-output (MIMO) or multi-user multiple-input, multiple-output (MU-MIMO) technology, the RxSP 326 may incorporate multiple demappers 314 and deinterleavers 312, matching the number of spatial streams in the transmission. In such scenarios, the RxSP 326 may also include a stream deparser for aggregating the outputs from the deinterleavers 312.

[0106] The decoder 310 processes the streams emanating from either deinterleaver 312 or the stream deparser. In a specific embodiment, the decoder 310 is equipped with a forward error correction (FEC) decoder. This FEC decoder can be configured as either a binary convolutional code decoder or a low-density parity-check decoder.

[0107] The RxSP 326 might also incorporate a descrambler to revert the decoding process on the decoded data. If binary convolutional code decoding is executed by decoder 310, the RxSP 326 could additionally employ an encoder deparser for aggregating the data decoded by multiple binary convolutional code decoders. Conversely, if low-density parity-check decoding is carried out by decoder 310, the use of the encoder deparser may not be necessary.

[0108] Before initiating a transmission, wireless devices, including wireless device 104, assess the availability of the wireless medium through clear channel assessment (CCA). CCA determines the medium as busy if it is occupied, and idle if it is available. [0109] The physical (PHY) entity of Institute of Electrical and Electronics Engineers (IEEE) 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In both OFDM and OFDMA Physical (PHY) layers, a station, such as wireless device 104, can transmit and receive PHY Protocol Data Units (PPDUs) in accordance with the mandatory PHY specifications. These specifications define a set of Modulation and Coding Schemes (MCS) and the maximum number of spatial streams. Certain PHY entities also specify downlink (DL) and uplink (UL) Multi-User (MU) transmissions, detailing a maximum number of space-time streams (STS) per user and a total number of STSs. PHY entities may support channel widths of 10 MHz, 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz for contiguous channels, as well as 80+80, 80+160 MHz, and 160+160 MHz for non-contiguous channels. Each channel comprises multiple subcarriers, also known as tones. PHY entities define signaling fields within a PPDU, such as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), to communicate essential information about PHY Service Data Unit (PSDU) attributes. For clarity and conciseness, the descriptions that follow will focus on OFDM -based 802.11 technology, referring to a station as a non-access point station unless specified otherwise.

[0110] FIG. 4 illustrates the relationships among Inter-Frame Spaces (IFSs), showcasing a Short IFS (SIFS), a Point Coordination Function IFS (PIFS), a Distributed Coordination Function IFS (DIFS), and an Arbitration IFS (AIFS) for Access Category ‘i’ (AIFS[i]). Additionally, the figure depicts a slot time and the transmission of a data frame, which is forwarded to a higher layer for processing. As illustrated, a wireless local area network (WLAN) device 104 initiates the transmission of the data frame following a backoff period, provided that a DIFS duration has passed with the medium remaining idle.

[0111] Management frames are utilized to exchange management information, which is not forwarded to higher layers. The subtypes of management frames include beacon frames, association request/response frames, probe request/response frames, and authentication request/response frames.

[0112] Control frames are employed to manage access to the medium. The subtypes of control frames encompass Request to Send (RTS), Clear to Send (CTS), and Acknowledgement (ACK) frames.

[0113] When the control frame does not serve as a response to another frame, wireless local area network (WLAN) device 104 transmits the control frame after initiating a backoff procedure, provided a DIFS (Distributed Coordination Function Inter-Frame Space) period has passed with the medium being idle. Conversely, if the control frame is a response to another frame, WLAN device 104 transmits the control frame following a SIFS (Short Inter-Frame Space) period, without performing a backoff or assessing the medium's idle status.

[0114] A wireless local area network (WLAN) device 104 equipped with quality of service (QoS) capabilities (sometimes referred to as a “QoS STA”) may initiate frame transmission after a backoff period, provided that the Arbitration Inter-Frame Space (AIFS) corresponding to the access category (AC) associated with the frame (i.e., AIFSfAC]) has elapsed. For transmissions by a QoS STA, data frames, management frames, and control frames (excluding response frames) can utilize the AIFSfAC] designated for the AC of the frame being transmitted.

[0115] A wireless local area network (WLAN) device 104 may initiate a backoff procedure upon finding the medium occupied when it is prepared to transmit a frame. This procedure entails calculating a random backoff duration consisting of N backoff slots, with each slot corresponding to a predefined slot time and N representing an integer greater than or equal to zero. The selection of the backoff period is influenced by the size of the Contention Window (CW). Furthermore, the backoff duration can be adjusted based on the Access Category (AC) of the frame in question. The commencement of all backoff slots follows either a Distributed Coordination Function Inter-Frame Space (DIFS) or an Extended Inter-Frame Space (EIFS), during which the medium must be observed as idle for the entirety of the interval.

[0116] When the wireless local area network (WLAN) device 104 observes no activity on the medium for the length of a designated backoff slot, the backoff procedure mandates reducing the backoff time by one slot time. Should the WLAN device 104 find the medium occupied during a backoff slot, the backoff process is paused and resumes only after the medium is perceived as idle for a complete Distributed Coordination Function Inter-Frame Space (DIFS) or Extended Inter-Frame Space (EIFS) interval. The device is then authorized to initiate the transmission or retransmission of the frame once the backoff timer counts down to zero.

[0117] The backoff procedure functions such that when multiple wireless local area network (WLAN) devices 104 defer and initiate the backoff process, each device selects a backoff time through a random function. The device with the shortest backoff time gains priority in the contention, thereby minimizing the likelihood of a collision.

[0118] FIG. 5 illustrates a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)-based frame transmission procedure designed to prevent collisions among frames on a channel, according to an embodiment. It depicts a first station (STA1) transmitting data, a second station (STA2) receiving the data, and a third station (STA3) situated in an area where it can receive a frame from either STA1, STA2, or both. Stations STA1, STA2, and STA3 may represent WLAN devices 104 as shown in FIG. 1. [0119] The station STA1 may assess whether the channel is occupied by performing carrier sensing. It can determine the channel's status based on the energy level present in the channel, the autocorrelation of signals within the channel, or by utilizing a Network Allocation Vector (NAV) timer to ascertain channel occupation.

[0120] After determining that the channel is not occupied by other devices (i.e., the channel is IDLE) during a DIFS (and performing backoff, if required), the station STA1 may transmit a Request-To-Send (RTS) frame to station STA2. Upon receiving the RTS frame, after a SIFS, station STA2 may transmit a Clear-To-Send (CTS) frame in response. If Dual-CTS is enabled and station STA2 is an access point, the access point may issue two CTS frames in response to the RTS frame — for example, a first CTS frame in a non-High Throughput (non-HT) format and a second CTS frame in the High Throughput (HT) format.

[0121] When station STA3 receives the RTS frame, it may set its Network Allocation Vector (NAV) timer for the transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using the duration information included in the RTS frame. If station STA3 receives the CTS frame, it may set its NAV timer for the transmission duration of subsequently transmitted frames based on the duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, station STA3 may update its NAV timer using the duration information from the new frame. Station STA3 does not attempt to access the channel until its NAV timer expires.

[0122] When station STA1 receives the CTS frame from station STA2, it may transmit a data frame to station STA2 after a SIFS period elapses from the time when the CTS frame has been completely received. Upon successfully receiving the data frame, station STA2 may transmit an ACK frame in response to the data frame after a SIFS period elapses.

[0123] When the NAV timer expires, the third station STA3 may determine whether the channel is busy using carrier sensing. Upon determining that the channel is not occupied by other devices during a DIFS period after the NAV timer has expired, station STA3 may attempt to access the channel after a contention window elapses, according to a backoff process.

[0124] 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 access point receiving a CF-End frame with the Basic Service Set Identifier (BSSID) of the access point as the destination address may respond by transmitting two additional CF-End frames: the first CF-End frame using Space Time Block Coding (STBC) and the 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 PHY Protocol Data Unit (PPDU) containing the CF-End frame. FIG. 5 illustrates station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.

[0125] With clear demand for higher peak throughput/capacity in Wi-Fi, a new working group for an amendment called 1 Ibe (Extreme High Throughput, EHT) has been created to support an increase in the peak PHY rate. Considering 802.1 lb to 802.1 lac, the peak PHY rate has increased by a factor of 5 or 11, as shown in the table of FIG. 6. In the case of 1 lax, known as Wi-Fi 6, the 1 lax working group focused on improving efficiency, not peak PHY rate, in dense environments. Note that the Max PHY data rate (in gigabits per second (Gbps)) and PHY rate enhancement (factor) for 1 Ibe could rely on the highest MCS (e.g., 4,096 QAM and its code rate) to be determined.

[0126] The focus of 1 Ibe is on wireless local area network (WLAN) indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 gigahertz (GHz) frequency bands. In addition to the peak PHY rate, different candidate features are under discussion, include some or all of: 320MHz bandwidth and more efficient utilization of non-contiguous spectrum; multi -band/multi-channel aggregation and operation; 16 spatial streams and multipleinput, multiple-output (MIMO) protocol enhancements; multi-access point coordination (e.g., coordinated and joint transmission); enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)); and, if needed, adaptation to regulatory rules specific to the 6 GHz spectrum.

[0127] Some features, like 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 for which feasibility demonstration is achievable.

[0128] As for operation bands (2.4/5/6 gigahertz (GHz)) for 1 Ibe, more than 1GHz of additional unlicensed spectrum is likely to be available around the year 2020 because the 6 GHz band (5.925 - 7.125 GHz) is being considered for unlicensed use. It would allow access points and stations to become tri-band devices. Larger than 160MHz data transmission (e.g., 320MHz) could be considered to increase the max PHY rate. For example, 320MHz or 160+160MHz data could be transmitted in the 6 GHz band. Alternatively, 160+160MHz data could be transmitted across the 5 and 6 GHz bands.

[0129] A transmitting station generates a PHY Protocol Data Unit (PPDU) frame and transmits it to a receiving station. The receiving station receives, detects, and processes the PPDU. If an Extremely High Throughput (EHT) PPDU frame comprises a legacy part (e.g., an L-STF field, an L-LTF field, and an L-SIG field), an EHT-SIG-A field, an EHT-SIG-B field, an EHT-HARQ field, an EHT-STF field, an EHT-LTF field, and an EHT-DATA field, then the table of FIG. 7 describes the fields of the EHT PPDU frame in more detail. However, many fields remain empty and are yet to be determined for further discussion.

[0130] The distributed nature of channel access networks, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area networks (WLANs), makes the carrier sense mechanism important for collision-free operation. The physical carrier sense of one station is responsible for detecting the transmissions of other stations. However, it may be impossible to detect every single case in some circumstances. For example, one station, which may be a long distance away from another station, may see the medium as idle and begin transmitting frames as well. To overcome this hidden node problem, the network allocation vector (NAV) has been introduced. However, as the IEEE 802.11 standard evolves to include multiple users' simultaneous transmission/reception scheduled within a BSS, such as UL/DL MU transmission in a cascaded manner, modified or newly defined mechanisms may be needed.

[0131] In this disclosure, multi-user (MU) transmission refers to cases where multiple frames are transmitted to or from multiple stations simultaneously using different resources, wherein examples of different resources are different frequency resources in OFDMA transmission and different spatial streams in multi-user multiple-input, multiple-output (MU-MIMO) transmission. Therefore, DL-OFDMA, DL-MU-MIMO, UL-OFDMA, and UL-MU-MIMO are examples of MU transmission.

[0132] Wireless local area network (WLAN) systems rely on the retransmission of medium access control (MAC) MPDUs when the TX (transmitter) does not receive the acknowledgment from the RX (receiver) OR when MPDUs are not decoded at the RX. In this ARQ (automatic repeat request) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted one. With the requirements for enhanced reliability and reduced latency, the 1 Ibe working group decided that it should evolve toward hybrid ARQ (HARQ).

[0133] There are two methods of HARQ processing. In the Type 1 HARQ scheme, also referred to as chase combining (CC), the signals to be retransmitted in this part are the same as the signals that failed before because all subpackets to be retransmitted use the same puncturing pattern. Puncturing is needed to remove some of the parity bits after encoding with an errorcorrection code. The reason for using the same puncturing pattern in CC-HARQ is to generate the coded data sequence with forward error correction (FEC) and make the receiver use maximum-ratio combining (MRC) to combine the received bits with the same bits from previous transmissions. In wireless local area network (WLAN) systems, four subpackets are created from one HARQ packet. For example, the information sequences are usually transmitted in packets with a fixed length. At a receiver, error correction and detection are carried out on the whole packet. If the packet is found to be in error, the conventional ARQ scheme is inefficient in the presence of burst errors. To solve this problem more efficiently, this situation can be improved if subpackets are applied. In subpacket transmissions, only those subpackets that include errors need to be retransmitted.

[0134] With subpackets, since the receiver uses both the current and the previously received subpackets to decode, the error probability in decoding decreases as the number of used subpackets increases. The decoding process passes the CRC check and ends when the packet is decoded without errors or the maximum number of subpackets is reached. Basically, because it operates in the stop-and-wait protocol, if the terminal can decode the packet, it sends an ACK to the transmitter. When the transmitter receives the ACK correctly, it terminates the HARQ transmission of the packet. If the terminal cannot decode the packet, it sends a NAK to the transmitter, and the transmitter performs the retransmission process.

[0135] In the Type 2 HARQ scheme, also referred to as Incremental Redundancy (IR), different puncturing patterns are used for each subpacket, so the signal of this portion changes for each subpacket. IR uses two puncturing patterns, alternating for odd-numbered and even-numbered transmissions, respectively, resulting in the coded data sequence with the coding rate which is used in IR HARQ. The redundancy scheme of IR improves the LLR (Log Likelihood Ratio) of the parity bits in order to combine information sent across different transmissions due to requests and lowers the code rate as additional subpackets are used, resulting in a lower error rate of the subpackets than CC. The puncturing pattern used in HARQ is indicated by the Subpacket Identity (SPID). The SPID of the first subpacket is always set to 0, and all the systematic bits and the punctured parity bits are transmitted in the first subpacket, and selfdecoding is possible when the receiving SNR environment is good. Generally, subpacket SPIDs to be transmitted are in increasing order but can be exchanged except for the first SPID.

[0136] As wireless local area network (WLAN) systems have improved, access point coordination has been discussed as a possible technology to be adopted in 1 Ibe, where there is a high-level classification depending on various access point coordination schemes. For example, there are two main types of techniques: the first type, called "coordinated," where data for a user is sent from a single access point, and the second type, called "joint," where data for a user is sent from multiple access points.

[0137] As for coordinated access point tech, multiple access points are either 1) transmitting on the same frequency resource based on coordination and forming spatial nulls to allow for simultaneous transmission from multiple access points, or 2) transmitting on orthogonal frequency resources by coordinating and splitting the spectrum to use it more efficiently. As for joint access point tech, multiple access points are transmitting jointly to a given user.

[0138] The solutions provided herein have been described with reference to a wireless LAN system; however, these solutions are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc.

[0139] An embodiment of the invention may be an article of manufacture in which a non- transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one or more data processing components (generically referred to here as a "processor" or "processing unit") to perform the operations described above. 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.

[0140] In some cases, an embodiment of the invention may be an apparatus (e.g., an access point station, a non-access point station, 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 above, the 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.

[0141] ENHANCED TRANSMIT OPPORTUNITY SHARING WITH COORDINATEDTIME DIVISION MULTIPLE ACCESS TRANSMISSION

[0142] Multi-access point (M-AP) coordination technology is a feature being considered for inclusion in the IEEE 802.11 standard, including IEEE 802.1 Ibe and future Wi-Fi standards. This technology offers benefits, such as improved spectral efficiency and reduced delay. Several M-AP technologies are currently under discussion, each with its own advantages and disadvantages. Coordinated BF/Nulling (Co-BF/Nulling) technology aims to mitigate interference between M-APs by sharing channel state information (CSI) feedback. Joint transmission (JTX) technology enables M-APs to transmit data simultaneously. Coordinated OFDMA/TDMA (C-OFDMA/C-TDMA) leverages time and frequency cooperation to enhance system throughput. Among these technologies, C-TDMA stands out as effective in terms of fairness, making it a promising candidate for future Wi-Fi standards.

[0143] C-TDMA technology offers several advantages in multi -access point (M-AP) scenarios. When data transmission occurs at a non-TXOP holder AP BSS, C-TDMA provides an opportunity for channel access. Compared to C-BF/Nulling technology, C-TDMA eliminates the need for CSI feedback. Additionally, C-TDMA has a simpler implementation compared to JTX technology, particularly in terms of mitigating synchronization issues between APs. To effectively utilize C-TDMA technology in M-AP scenarios, it is useful to share control information among APs.

[0144] This present disclosure discloses an enhanced Multi-User Request-to-Send Transmit Opportunity Sharing (MU-RTS TXS) trigger frame for performing C-TDMA technology in Ultra High Reliability (UHR) and future Wi-Fi standards. The disclosed frame is an expansion of the MU-RTS TXS trigger frame used in the 802.1 Ibe standard, enabling efficient coordination and communication among APs to maximize the benefits of C-TDMA technology in multi-access point environments.

[0145] USER INFORMATION FIELD IN ENHANCED MU-RTS TXS TRIGGER FRAME [0146] The disclosed enhanced MU-RTS TXS trigger frame extends the functionality of the existing MU-RTS TXS trigger frame in the 802.1 Ibe standard. This enhanced trigger frame enables a TXOP holder AP, also known as the sharing AP, to allocate a portion of its obtained TXOP to one or more non-TXOP holder APs, referred to as shared APs. The user info field of the enhanced MU-RTS TXS trigger frame is illustrated in FIG. 8. The subfields 802, 806, and 808 are different between the enhanced MU-RTS TXS trigger frame and the existing MU-RTS TXS trigger frame. These modifications allow for efficient allocation and coordination of TXOP resources among multiple APs, facilitating the implementation of C-TDMA technology in multiaccess point scenarios.

[0147] As shown in FIG. 8, the user information field 800 of the enhanced MU-RTS TXS trigger frame encompasses five subfields 802, 804, 806, 808, and 810. The shared AP's identifier 802 represents the AP that receives the enhanced MU-RTS TXS trigger frame from the sharing AP, and it can be a BSS color, AP-ID, or AP AID. The RU Allocation 804 and PS160 810 subfields serve the same purpose as in the existing MU-RTS TXS trigger frame. The allocation duration 806 indicates the portion of a shared TXOP. The Group BSS color and/or Bound subfield 808 has two components: the Group BSS color 812, which is a numerical identifier for the participating APs and STAs in C-TDMA, and the Bound 814, which is related to NAV setting and has two options depending on the number of bits used. The Bound field 814 determines the NAV setting based on the BSS color or shared AP's identifier 802. The Group BSS color 812 and Bound field 814 can be located in the user info field 800, PHY preamble signal field, or common info field of the enhanced MU-RTS TXS trigger frame. The number of bits for each subfield 802, 806, and 808 is specified in FIG. 8, with the shared AP's identifier, allocation duration, and Group BSS color using no more than 12, 9, and 9 bits, respectively, while the Bound field uses 1 bit. The number of bits can be variable.

[0148] The concept of "Group BSS Color" is an extension of the "BSS Color" mechanism introduced in IEEE 802.1 lax (Wi-Fi 6). Generally speaking, “BSS Color” involves assigning a unique identifier or "color" to each Basic Service Set (BSS), which is essentially a network made up of stations (devices) that communicate with the same access point. This color helps devices determine whether incoming signals come from their own BSS or from an overlapping BSS. If the signal is from a different BSS with a different color and is below a certain signal strength threshold, the device may ignore it, thereby reducing unnecessary signal processing and decreasing interference.

[0149] Generally speaking, "Group BSS Color" extends the idea of BSS Color by allowing multiple BSSs to be grouped under a single color. This can be particularly useful in managed environments, like enterprise or campus networks, where multiple access points might be under the same administrative control. Group BSS Color enables these access points to coordinate more effectively by treating them as part of the same group.

[0150] Generally speaking, the term "MyBSS Color" refers to the specific color assigned to the Basic Service Set (BSS) to which a device is currently connected. MyBSS Color acts as a local identifier for the network segment a device is actively participating in. It is used by the device to identify its own network frames and to filter out other signals.

[0151] In the context of the user information field 800 of the enhanced MU-RTS TXS trigger frame, the Bound subfield 814 is related to the Network Allocation Vector (NAV) setting and has two possible options, both using a single bit.

[0152] Option 1 focuses on the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS trigger frame. When the Bound field bit 814 is set to 1, and if the BSS color in the PHY preamble signal field matches the MyBSS color, the receiving device sets the intra NAV. However, if the BSS colors do not match, the basic NAV is not set. When the Bound field bit 814 is set to 0, it is reserved for future use.

[0153] Option 2, on the other hand, considers the shared AP's identifier 802 (e.g., the shared AP's BSS color) in the user info field 800 of the enhanced MU-RTS TXS trigger frame. If the Bound field bit 814 is set to 1 and the shared AP's identifier 802 matches the MyBSS color, the receiving device does not set the basic NAV. If the identifiers do not match, the device follows the existing NAV rule. Similar to Option 1, when the Bound field bit 814 is set to 0, it is reserved for future use. [0154] These two options provide flexibility in determining how the NAV should be set based on either the BSS color in the PHY preamble signal field or the shared AP's identifier 802 in the user info field 800 of the enhanced MU-RTS TXS trigger frame.

[0155] IEEE 802.11BE TRIGGERED TXOP SHARING MODE SUBFIELD ENCODING [0156] To facilitate Coordinated-Time Division Multiple Access (C-TDMA), it is necessary to allocate a portion of the sharing AP's TXOP (Transmit Opportunity) to the shared AP. However, before this allocation can take place, a mode must be defined to enable the sharing of the obtained TXOP between the APs. The current 802.1 Ibe standard includes a TXOP sharing mode, as illustrated in FIG. 9.

[0157] The current IEEE 802.1 Ibe standard defines the encoding and interpretation of the Triggered TXOP Sharing Mode subfield. This subfield is used to indicate the mode of operation for triggered TXOP sharing between devices in a wireless network.

[0158] The table of FIG. 9 encompasses four rows, each representing a different encoding value and its corresponding description. The possible encoding values are 00, 01, 10, and 11 (binary). [0159] Encoding 00: This indicates that triggered TXOP sharing is disabled or not supported by the device.

[0160] Encoding 01 : This value indicates another mode of triggered TXOP sharing, such as "Constrained Mode." In this mode, the TXOP holder can share its TXOP with other devices, but there might be certain constraints or limitations on the sharing process.

[0161] Encoding 10: This represents a specific mode of triggered TXOP sharing, such as "Non- Constrained Mode." In this mode, the TXOP holder can share its TXOP with other devices without strict constraints.

[0162] Encoding 11 : This value is reserved for future use or extensions to the triggered TXOP sharing modes.

[0163] The purpose of this subfield is to facilitate efficient TXOP sharing among devices in a wireless network. By specifying the triggered TXOP sharing mode, devices can coordinate and manage their TXOP usage more effectively, leading to improved network performance and resource utilization.

[0164] It should be noted that the specific details and terminology used in the table may vary based on the final version of the IEEE 802.1 Ibe standard.

[0165] TRIGGERED TXOP SHARING MODE SUBFIELD ENCODING FOR ULTRA HIGH RELIABILITY STANDARD OR OTHER FUTURE IEEE 802.11 STANDARD

[0166] In this disclosure, a new mode of TXOP sharing between APs is disclosed, utilizing the reserved bit corresponding to a triggered TXOP sharing mode subfield value of 3 (encoding: 11). This new mode allows for more efficient and flexible TXOP sharing in C-TDMA scenarios. FIG. 10 provides a table of the new mode of TXOP sharing between APs.

[0167] This new mode is designed to facilitate the implementation of Multi-AP (M-AP) schemes, such as Coordinated Time Division Multiple Access (C-TDMA) and Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA), among others.

[0168] In this new mode, a scheduled AP (Access Point) can initiate a Multi-User Request-to- Send (MU-RTS) TXS sharing procedure. The MU-RTS frame serves as the trigger to start the TXOP sharing process. During this procedure, the scheduled AP can transmit one or more MAC Protocol Data Units (MPDUs) addressed to a participating AP, which is typically an associated AP. In this context, the “scheduled” AP is the sharing AP that obtains the TXOP. In other words, the scheduled AP is the TXOP holder. The sharing AP which is the TXOP holder can control the C-TDMA, and it can determine the shared AP(s) from candidates of the shared AP(s) set.

[0169] The purpose of this new TXOP sharing mode is to enable efficient coordination and collaboration among multiple APs in a wireless network. By allowing a scheduled AP to transmit MPDUs directly to a participating AP, the M-AP schemes can be implemented more effectively.

[0170] For example, in the case of C-TDMA, the scheduled AP can allocate specific time slots to the participating AP, enabling it to transmit during its assigned time slots without contention. Similarly, in the case of C-OFDMA, the scheduled AP can allocate specific frequency resources to the participating AP, allowing it to transmit on its assigned subcarriers.

[0171] By leveraging this new mode of TXOP sharing, the performance and efficiency of wireless networks can be enhanced, particularly in scenarios with multiple APs and high-density environments. The M-AP schemes supported by this mode can help reduce contention, minimize interference, and optimize resource utilization, ultimately leading to improved network throughput and user experience.

[0172] In the disclosed C-TDMA scenario, when the shared AP receives the enhanced MU-RTS TXS trigger frame, and the associated STAs with the shared AP also overhear this frame, the new mode dictates a specific response mechanism. According to the new mode, only the shared AP is responsible for sending a CTS (Clear to Send) frame in response to the received enhanced MU-RTS TXS trigger frame. This means that the associated STAs do not send any response frames, even though they have overheard the enhanced MU-RTS TXS trigger frame. This approach simplifies the response process and reduces the overhead associated with multiple devices sending CTS frames, ultimately improving the efficiency of the C-TDMA operation. [0173] In a Coordinated-Time Division Multiple Access (C-TDMA) scenario, the sharing AP transmits an enhanced MU-RTS TXS trigger frame to the shared AP. When this frame is overheard by the stations (STAs) associated with the shared AP, they set their basic Network Allocation Vector (NAV). The basic NAV is a mechanism used to prevent STAs from accessing the medium during a reserved transmission period. However, if the basic NAV is set by the sharing AP, it can lead to a problem where the STAs associated with the shared AP are unable to send uplink data during the allocated TXOP duration for the shared AP. This situation results in a waste of resources and reduces the efficiency of the C-TDMA scheme. To address this issue, the C-TDMA protocol should be designed to allow uplink traffic from the STAs associated with the shared AP during the allocated shared AP's TXOP duration. By enabling uplink traffic during this period, the C-TDMA protocol can maximize resource utilization and improve overall system performance.

[0174] MULTI-AP AND STA TOPOLOGY FOR C-TDMA

[0175] FIG. 11 illustrates the topology of the APs and STAs involved in the Coordinated-Time Division Multiple Access (C-TDMA) scheme. In this setup, it is important to differentiate between the roles of the participating APs. Each AP involved in C-TDMA can have a mechanism to indicate whether it can initiate the coordination process or not. The AP that initiates the coordination is referred to as the sharing AP, while the AP that receives the coordination instructions is called the shared AP.

[0176] In the scenario depicted in FIG. 11, API successfully occupies the channel during the prepare phase, which is a preliminary stage in the C-TDMA process. By occupying the channel, API assumes the role of the sharing AP. This means that API will be responsible for coordinating the TXOP (Transmit Opportunity) allocation and sharing among the participating APs.

[0177] On the other hand, AP2, which is the other AP involved in the C-TDMA setup, becomes the shared AP. As the shared AP, AP2 will follow the coordination instructions provided by the sharing AP (API) and will be allocated a portion of the TXOP for its own transmissions.

[0178] This clear distinction between the sharing AP and the shared AP is useful for the effective implementation of the C-TDMA scheme, as it ensures proper coordination and efficient utilization of the available TXOP resources.

[0179] NAV SNAPSHOT DURING ENHANCED TXS/CTS FRAME EXCHANGE FOR C- TDMA [0180] FIG. 12 provides a snapshot of Network Allocation Vector (NAV) values, such as basic NAV and intra NAV, in a scenario where API transmits an enhanced MU-RTS TXS trigger frame to AP2, and AP2 responds with a CTS frame, based on the topology shown in FIG. 11. [0181] In this snapshot, STA21, which is associated with AP2, sets its basic NAV according to the enhanced MU-RTS TXS trigger frame received from API. However, this basic NAV value prevents STA21 from participating in uplink transmission during the time allocated to AP2. As a result, STA21 is unable to send data to AP2 during its designated allocation time.

[0182] Furthermore, the snapshot reveals that STA11, which is associated with API, attempts to occupy the channel during AP2's allocation time. This can be considered as interference from the perspective of AP2's BSS (Basic Service Set). To mitigate this interference and ensure the smooth operation of C-TDMA, it can be useful to implement a mechanism that defers STA1 l's transmission until the end of AP2's allocation time.

[0183] Addressing these issues is useful for the proper functioning of the C-TDMA scheme. By preventing STA21 from setting the basic NAV based on the enhanced MU-RTS TXS trigger frame from API, and by deferring STA1 l's transmission during AP2's allocation time, the interference can be minimized, and the efficiency of the C-TDMA scheme can be improved.

[0184] The disclosed solution addresses the issues mentioned earlier by introducing an enhanced MU-RTS TXS trigger frame. The purpose of this enhanced frame in an embodiment is twofold. [0185] First, it prevents STA21, which is associated with AP2, from setting the basic NAV based on the information received from the sharing AP (API). By doing so, STA21 is no longer restricted by the basic NAV and can freely participate in transmission during the time allocated to AP2.

[0186] Second, the enhanced MU-RTS TXS trigger frame includes a duration field that specifies the allocation duration time to be shared with AP2. By applying this allocation duration time to the duration field, STA11, which is associated with API, is prevented from attempting to occupy the channel during AP2's allocation time.

[0187] The combination of these two modifications to the enhanced MU-RTS TXS trigger frame effectively resolves the issues previously identified. STA21 can now engage in transmission during AP2's allocation time without being hindered by the basic NAV set by the sharing AP. Simultaneously, STA11 is blocked from occupying the channel during AP2's allocation time, eliminating the potential interference it could cause.

[0188] OPTION 1

[0189] In an embodiment, a solution addresses the issue of stations (STAs) associated with a shared access point (AP) being unable to transmit data due to the basic Network Allocation Vector (NAV) set by the sharing AP's enhanced Multi-User Request-to-Send Transmit Sharing (MU-RTS TXS) frame. The solution utilizes the Bound (1 bit) field in the enhanced MU-RTS TXS frame to match the Basic Service Set (BSS) color in the PHY preamble signal field with the STA's own BSS color (MyBSS color).

[0190] When an STA overhears the enhanced MU-RTS TXS frame, it checks the Bound field. If the Bound bit is set to 1, the STA compares the BSS color in the PHY preamble signal field (e.g., UHR SIG field or future standard SIG field) of the enhanced MU-RTS TXS frame with its MyBSS color. If the BSS colors match, the STA sets the intra-NAV, indicating that it should refrain from transmitting during the allocated time. However, if the BSS colors do not match, the STA does not set the basic NAV, preventing it from being blocked by the NAV set by the sharing AP.

[0191] When the Bound field is set to 1, and the BSS color in the SIG field matches the MyBSS color, the STA sets the intra-NAV. Otherwise, it does not set the basic NAV. If the Bound field is set to 0, it is reserved for future or other use.

[0192] This solution allows STAs associated with the shared AP to determine whether they should set the intra-NAV or not based on the BSS color matching, enabling them to transmit during their allocated time and avoiding unnecessary blocking by the basic NAV set by the sharing AP.

[0193] The behavior of stations (STAs) in the scenario of Option 1 can be described with respect to FIG. 12, where the Bound bit field value is set to 1 in the enhanced MU-RTS TXS frame. In this case, STA11 and STA12 compare the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS frame with their own BSS color (MyBSS color). The BSS color in the PHY preamble is designed to be API's BSS color.

[0194] Since the BSS colors of STA11 and STA12 match API's BSS color, they set the intra- NAV, indicating that they can transmit during the allocated time for their associated AP (API). However, on the STA21 side, the BSS color does not match, so STA21 does not set the basic NAV.

[0195] The Bound field is not limited to the user info field but can also be located in the PHY preamble signal field, common info field, or any other location within the enhanced MU-RTS TXS frame.

[0196] FIG. 13 provides a snapshot of the NAV setting when applying Option 1. It demonstrates that STA21 does not set the basic NAV, allowing it to transmit uplink data during AP2's allocated time in the Coordinated Time Division Multiple Access (C-TDMA) scenario. [0197] Option 1 ensures that STAs associated with the shared AP (AP2) can efficiently utilize their allocated transmission time without being unnecessarily blocked by the basic NAV set by the sharing AP (API). By using the Bound bit field and comparing the BSS colors, STAs can determine whether to set the intra-NAV or not, enabling efficient coordination and communication within the C-TDMA scheme.

[0198] BOUND FIELD LOCATION IN ENHANCED MU-RTS TXS FRAME

[0199] FIG. 14, FIG. 15, and FIG. 16 illustrate three different examples of the enhanced MU- RTS TXS trigger frame structure 1400, 1500, and 1600, respectively. These figures showcase some possible locations of the Bound field within the frame structure.

[0200] In FIG. 14, the Bound bit is located in the PHY SIG (Signal) field 1402 of the frame 1400 where it is easily accessible for stations to determine their NAV setting behavior.

[0201] FIG. 15 depicts the frame structure 1500 where the Bound bit is positioned in the common info field 1506 of the PHY service data unit (PSDU) field 1504. The common info field 1506 typically contains information that is relevant to all the stations receiving the frame, making it another suitable location for the Bound bit.

[0202] Lastly, FIG. 16 presents the frame structure 1600 with the Bound bit situated in the user info field 1608 of the PSDU field 1604. The user info field 1608 usually carries information specific to individual stations or groups of stations, providing another possible location for the Bound bit.

[0203] In addition to the Bound field, the frame structures 1400, 1500, and 1600 also include the Triggered TXOP sharing mode field, as explained above with respect to FIG. 10, and the shared AP BSS color field, as described above with respect to FIG. 8. These fields provide additional information necessary for the proper operation of the enhanced MU-RTS TXS trigger frame in the context of coordinated multi-AP transmission schemes.

[0204] By offering different options for the location of the Bound bit within the enhanced MU- RTS TXS trigger frame structure, the system provides flexibility in implementing the NAV setting mechanism based on the specific requirements and constraints of the wireless network.

[0205] OPTION 2

[0206] A second option uses the Bound (1 bit) field in the enhanced MU-RTS TXS frame to match the BSS color of the shared AP in the user info field with the STA's own BSS color (MyBSS color).

[0207] When an STA overhears the enhanced MU-RTS TXS frame, it checks the Bound field. If the Bound bit is set to 1, the STA compares the BSS color in the user info field of the enhanced MU-RTS TXS frame with its MyBSS color. If the BSS colors match, the STA does not set the basic NAV, allowing it to transmit during the allocated time for its associated AP (shared AP). However, if the BSS colors do not match, the STA sets the intra-NAV, indicating that it should refrain from transmitting during the allocated time.

[0208] When the Bound field is set to 1, and the BSS color (shared AP) in the user info field matches the MyBSS color, the STA does not set the basic NAV. Otherwise, it sets the intra- NAV. If the Bound field is set to 0, it is reserved for future use.

[0209] This solution allows STAs associated with the shared AP to determine whether they should set the basic NAV or the intra-NAV based on the BSS color matching in the user info field. By not setting the basic NAV when the BSS colors match, STAs can transmit during their allocated time, avoiding unnecessary blocking by the NAV set by the sharing AP. On the other hand, when the BSS colors do not match, STAs set the intra-NAV to prevent interference with transmissions from other APs.

[0210] Option 2 provides an alternative approach to Option 1 by using the BSS color in the user info field instead of the PHY preamble signal field for matching purposes.

[0211] FIG. 12 and FIG. 13 can be used to illustrate the operation of Option 2 when the Bound bit indication value is set to 1 in the enhanced MU-RTS TXS frame. In this scenario, STA11 and STA12 compare the BSS color in the user info field of the enhanced MU-RTS TXS frame with their own MyBSS color. The BSS color in the user info field is designed to be the shared AP's BSS color.

[0212] Since the BSS color in the user info field does not match the MyBSS color of STA11 and STA12, they set the intra-NAV. This means that STA11 and STA12 are not associated with the shared AP and should refrain from transmitting during the allocated time.

[0213] On the other hand, STA21 finds that the BSS color in the user info field matches its MyBSS color. As a result, STA21 does not set the basic NAV, indicating that it is associated with the shared AP and can transmit during the allocated time for its associated AP.

[0214] Example locations of the Bound bit field are shown in FIG. 14, FIG. 15, and FIG. 16, providing a visual representation of possible positions within the enhanced MU-RTS TXS frame.

[0215] FIG. 13 presents a snapshot of the NAV setting when applying Option 2. It demonstrates that STA21 does not set the basic NAV, allowing it to transmit during the allocated time for its associated AP.

[0216] This approach ensures that STAs associated with the shared AP can efficiently utilize their allocated transmission time without being unnecessarily blocked by the basic NAV set by the sharing AP. By comparing the BSS color in the user info field with the MyBSS color, STAs can determine their association with the shared AP and set the NAV accordingly.

[0217] EXAMPLE FRAME EXCHANGE SEQUENCE

[0218] FIG. 17 illustrates an example frame exchange sequence in accordance with Option 1 and Option 2. The sequence consists of a prepare phase, during which the multiple access points (M-APs) are configured to perform Coordinated Time Division Multiple Access (C-TDMA). [0219] In the prepare phase, two steps take place. First, the sharing AP and shared AP are determined. The sharing AP is responsible for allocating a portion of its transmission opportunity (TXOP) to the shared AP, allowing the shared AP to transmit during the allocated time.

[0220] Second, each AP's Basic Service Set (BSS) color is shared among the participating APs. This sharing of BSS colors is done through the beacon or probe response frames, which are management frames used for AP discovery and information exchange. By sharing the BSS colors, the APs establish a common understanding of their respective identities and coverage areas.

[0221] The sharing of BSS colors is useful for the option of Option 1 and Option 2. In these options, the stations (STAs) associated with the shared AP use the BSS color information to determine whether they should set the Network Allocation Vector (NAV) and refrain from transmitting or if they can transmit during the allocated time for their associated AP.

[0222] By having the BSS colors shared among the APs during the prepare phase, the STAs can effectively compare the BSS colors received in the enhanced MU-RTS TXS frame with their own BSS color (MyBSS color) and make the appropriate decision regarding NAV setting and transmission.

[0223] OPTION 3

[0224] A third option involves checking the Group BSS color (1-3 bit) field and the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS frame. The Group BSS color is a numerical identifier assigned to APs and STAs participating in the M-AP scheme (e.g., C- TDMA). APs and STAs not participating in any M-AP scheme could set the Group BSS color value to 0.

[0225] When STAs overhear the enhanced MU-RTS TXS frame, they compare the Group BSS color in the frame with their own Group BSS color. If the Group BSS colors do not match, the STAs follow the existing NAV rule. However, if the Group BSS colors match, the STAs proceed to compare the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS frame with their own BSS color. [0226] If the BSS colors match, the STAs set the intra-NAV, indicating that they are not associated with the shared AP and should refrain from transmitting during the allocated time. On the other hand, if the BSS colors do not match, the STAs do not set the basic NAV, indicating that they are associated with the shared AP and can transmit during the allocated time.

[0227] This solution provides a hierarchical approach to determine the NAV setting behavior of STAs based on their participation in the M-AP scheme and their association with the shared AP. By using the Group BSS color and BSS color comparisons, STAs can efficiently determine whether they should set the intra-NAV or not set the basic NAV, ensuring proper coordination and communication within the C-TDMA scheme.

[0228] In an embodiment, group BSS color is a 1-3 bit field that identifies the group of stations and access points participating in a Multi-AP scheme. According to Option 3, when an STA receives an enhanced MU-RTS TXS frame, it first compares the Group BSS color in the frame with its own Group BSS color.

[0229] If the Group BSS colors match, the STA proceeds to compare the BSS color in the PHY preamble of the enhanced MU-RTS TXS frame with its own BSS color. If both BSS colors match, the STA sets the intra-NAV, indicating that it is associated with the shared AP and can transmit during the allocated time. If the BSS colors do not match, the STA does not set the basic NAV, indicating that it is not associated with the shared AP and should refrain from transmitting during the allocated time.

[0230] If the Group BSS colors do not match, the STA follows the existing NAV rule, which could involve setting the NAV based on the duration field in the frame or other standard-defined behaviors.

[0231] Using FIG. 12 to illustrate Option 3, STA11, STA12, and STA21 have a Group BSS color that matches the Group BSS color in the enhanced MU-RTS TXS frame. As a result, they compare the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS frame with their own BSS color. STA11 and STA12 have matching BSS colors, so they set the intra- NAV. STA21's BSS color does not match, so it does not set the basic NAV. FIG. 13 shows a snapshot of the NAV setting when applying Option 3.

[0232] GROUP BSS COLOR FIELD LOCATION IN ENHANCED MU-RTS TXA FRAME [0233] The Group BSS color field can be located in various parts of the enhanced MU-RTS TXS frame, such as the user info field, PHY preamble signal field, common info field, or any other location.

[0234] FIG. 18, FIG. 19, and FIG. 20 illustrate possible locations of the Group BSS color field within the enhanced MU-RTS TXS trigger frame. [0235] Three different frame structures 1800, 1900, and 2000 are presented, each showcasing a different placement of the Group BSS color field:

[0236] In the first frame structure 1800, the Group BSS color is located in the SIG (Signal) field 1802. The SIG field 1802 is part of the PHY preamble and contains information about the transmission parameters and frame format.

[0237] The second frame structure 1900 shows the Group BSS color in the common info field 1906. The common info field 1906 typically contains information that is relevant to all the STAs receiving the enhanced MU-RTS TXS trigger frame 1900.

[0238] In the third frame structure 2000, the Group BSS color is placed in the user info field 2008. The user info field 2008 usually carries information specific to individual STAs or groups of STAs.

[0239] By presenting these different frame structures 1800, 1900, and 2000, FIG. 18, FIG. 19, and FIG. 20 highlight the flexibility in positioning the Group BSS color field within the enhanced MU-RTS TXS trigger frame. This flexibility allows for adapting the frame structure based on the specific requirements and design choices of the Multi-AP system.

[0240] The placement of the Group BSS color field in different parts of the frame, such as the SIG field, common info field, or user info field, can impact how the information is processed and interpreted by the receiving STAs. The choice of location may depend on factors such as the desired level of accessibility, the intended recipients of the information, and the overall frame structure.

[0241] OPTION 4

[0242] Another option, Option 4, focuses on checking the Group BSS color (1-3 bit) field and the BSS color located in the user info field of the enhanced MU-RTS TXS frame. The Group BSS color is identified during the prepare phase, as illustrated in FIG. 17.

[0243] When STAs overhear the enhanced MU-RTS TXS frame, they compare the Group BSS color in the frame with their own Group BSS color. If the Group BSS colors do not match, the STAs follow the existing NAV rule, which could involve setting the NAV based on the duration field in the frame or other standard-defined behaviors.

[0244] However, if the Group BSS colors match, the STAs proceed to compare the BSS color in the user info field of the enhanced MU-RTS TXS frame with their own BSS color. This comparison determines whether the STAs are associated with the shared AP.

[0245] If the BSS colors match, it indicates that the STAs are associated with the shared AP. In this case, the STAs do not set the basic NAV, allowing them to transmit during the allocated time for their associated AP. [0246] On the other hand, if the BSS colors do not match, it means that the STAs are not associated with the shared AP. In this situation, the STAs set the intra-NAV, indicating that they should refrain from transmitting during the allocated time.

[0247] Option 4 provides a hierarchical approach to determine the NAV setting behavior of STAs based on their participation in the Multi-AP scheme and their association with the shared AP. By first checking the Group BSS color and then comparing the BSS color in the user info field, STAs can efficiently coordinate their transmissions within the Multi-AP scheme while avoiding unnecessary blocking of their transmissions.

[0248] This solution leverages the user info field to convey the BSS color information, allowing for targeted communication and coordination among the STAs participating in the Multi-AP scheme.

[0249] Under Option 4, if the Group BSS color in the enhanced MU-RTS TXS frame matches the STA's own Group BSS color, the STA proceeds to compare the BSS color in the user info field of the frame with its own BSS color.

[0250] If both BSS colors match, it indicates that the STA is associated with the shared AP. In this case, the STA does not set the basic NAV, allowing it to transmit during the allocated time for its associated AP.

[0251] On the other hand, if the Group BSS colors match but the BSS colors do not match, it means that the STA is not associated with the shared AP. In this situation, the STA sets the intra-NAV, indicating that it should refrain from transmitting during the allocated time.

[0252] If the Group BSS colors do not match, the STA follows the existing NAV rule, which could involve setting the NAV based on the duration field in the frame or other standard-defined behaviors.

[0253] Option 4 can be illustrates with respect to FIG. 12, STA11, STA12, and STA21 have a Group BSS color that matches the Group BSS color in the enhanced MU-RTS TXS frame. As a result, they compare the BSS color in the user info field of the frame with their own BSS color. STA11 and STA12 find that their BSS colors do not match, so they set the intra-NAV. STA21's BSS color matches, so it does not set the basic NAV.

[0254] FIG. 13 provides a snapshot of the NAV setting when applying Option 4, illustrating the resulting NAV states for different STAs based on their Group BSS color and BSS color comparisons.

[0255] FRAME EXCHANGE PROCEDURE EXAMPLES [0256] FIG. 21, FIG. 22, and FIG. 23 present examples of the frame exchange procedure, which is divided into three phases: the prepare phase, the C-TDMA setup/Data and Ack phase, and the phase after C-TDMA.

[0257] FIG. 21, FIG. 22, and FIG. 23 depict three different scenarios or use cases of Coordinated Time Division Multiple Access (C-TDMA) in a Multi-AP environment, focusing on the behavior of AP2 and its associated STAs.

[0258] In the first scenario of FIG. 21, AP2 cascades the allocated time it receives from the sharing AP to its associated STAs. This means that AP2 further divides and assigns the allocated time slots to the STAs connected to it, allowing them to access the medium and transmit data during their respective time slots. This cascading of allocation time enables efficient utilization of the shared resources and ensures fair access for the associated STAs.

[0259] The second scenario of FIG. 22 involves AP2 using the allocated time for downlink service to its associated STAs. During the time slots assigned to AP2, it can transmit data to the STAs connected to it. This downlink service may include sending data packets, management frames, or other relevant information from AP2 to its associated STAs. By utilizing the allocated time for downlink transmissions, AP2 can efficiently deliver data to the STAs without contention from other APs or STAs.

[0260] In the third scenario of FIG. 23, AP2 uses the allocated time to receive uplink data from its associated STAs. During the assigned time slots, the STAs connected to AP2 can transmit data to AP2. This uplink data may include user data, control information, or other relevant messages from the STAs to AP2. By dedicating the allocated time for uplink transmissions, AP2 can efficiently collect data from its associated STAs without interference from other devices in the network.

[0261] These three scenarios demonstrate the flexibility and versatility of C-TDMA in managing the shared resources and facilitating efficient communication between AP2 and its associated STAs. By leveraging the allocated time for cascading allocation, downlink service, and uplink data reception, AP2 can optimize network performance and ensure fair access for its associated STAs within the Multi-AP environment.

[0262] OBSS AND MULTI-AP TOPOLOY FOR C-TDMA

[0263] An example wireless network topology is illustrated in FIG. 24, which involves three access points (APs) in a Multi-AP scenario utilizing Coordinated Time Division Multiple Access (C-TDMA). The scenario includes API, AP2, and AP3, where AP3 is considered an Overlapping Basic Service Set (OBSS) AP. [0264] Through the prepare phase, as depicted in FIG. 17, API and AP2 are identified as the sharing AP and shared AP, respectively. This designation determines their roles in the C-TDMA coordination process, with API responsible for sharing its allocated time with AP2.

[0265] In the prepare phase, each AP's BSS (Basic Service Set) color is exchanged between the participating APs. This exchange occurs through the beacon or probe response frames, which are management frames used for AP discovery and information sharing. By sharing the BSS colors, the APs establish a common understanding of their respective identities and coverage areas.

[0266] Additionally, the Group BSS color is determined during the prepare phase. The Group BSS color serves as an identifier for the group of APs and STAs participating in the C-TDMA scheme. This color is shared among the involved APs and STAs, enabling them to recognize and coordinate with the devices belonging to the same C-TDMA group.

[0267] The prepare phase sets up the C-TDMA coordination. Through the exchange of BSS colors and the assignment of the Group BSS color, the APs and STAs establish the necessary information to effectively participate in the C-TDMA scheme.

[0268] NAV SETTING SNAPSHOT DURING OBSS MU-RTS/CTS CONTROL FRAME EXCHANGE AND IN OBSS AND MULTI-AP SCENARIOS FOR C-TDMA

[0269] Example snapshots of the Network Allocation Vector (NAV) settings in two different scenarios involving Overlapping Basic Service Set (OBSS) and Multi-AP coordination using Coordinated Time Division Multiple Access (C-TDMA) are illustrated in FIG. 25 and FIG. 26. [0270] FIG. 25 illustrates the NAV setting when an OBSS AP exchanges Multi-User Request- to-Send/Clear-to-Send (MU-RTS/CTS) control frames with its associated stations, specifically STA32 and STA33.

[0271] FIG. 26 shows the NAV setting when multiple APs (API and AP3) are involved in C- TDMA coordination.

[0272] In FIG. 26, the basic NAV of STA21 was set due to the enhanced MU-RTS TXS frame transmitted by API. As a result, STA21 cannot participate in an uplink transmission during AP’s allocation time. However, if Option 3 and Option 4 are applied, STA21 would not set the basic NAV and would have an opportunity to transmit uplink data during AP2’s allocation time.

[0273] NAV SETTING SNAPSHOT UNDER OPTION 3 AND OPTION 4

[0274] When Option 3 is applied, STA31 could overhear the enhanced MU-RTS TXS trigger frame transmitted from API to AP3. In this case, STA31 compares the Group BSS color in the enhanced MU-RTS TXS trigger frame with its own Group BSS color and finds that they do not match. As a result, STA31 follows the existing Network Allocation Vector (NAV) rule and sets the basic NAV, as indicated in FIG. 27. [0275] On the other hand, STA11 and STA12, which are participating in the C-TDMA scheme, also compare the Group BSS color in the enhanced MU-RTS TXS trigger frame with their own Group BSS color. Since they are part of the C-TDMA scheme, the Group BSS color matches. Subsequently, STA11 and STA12 compare the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS trigger frame with their own BSS color. The BSS color also matches, indicating that STA11 and STA12 are associated with API. Consequently, STA11 and STA12 set the intra NAV to coordinate their transmissions within the C-TDMA scheme.

[0276] For STA21, although the Group BSS color in the enhanced MU-RTS TXS trigger frame matches its own Group BSS color, the BSS color in the PHY preamble signal field does not match STA21's BSS color. This indicates that STA21 is not associated with API. As a result, STA21 does not set the basic NAV, as depicted in FIG. 27.

[0277] By comparing the Group BSS color and BSS color, STAs can determine whether to set the basic NAV, set the intra NAV, or not set the NAV at all. This allows for efficient coordination and resource utilization within the C-TDMA scheme while avoiding unnecessary NAV restrictions for non-participating STAs.

[0278] For Option 4, when API transmits an enhanced Multi-User Request-to-Send Transmit Sharing (MU-RTS TXS) frame to AP2, STA31, which is not participating in the C-TDMA scheme, could overhear the frame. STA31 compares the Group BSS color in the enhanced MU- RTS TXS trigger frame with its own Group BSS color and finds that they do not match. As a result, STA31 follows the existing Network Allocation Vector (NAV) rule.

[0279] STA11 and STA12, which are participating in the C-TDMA scheme, compare the Group BSS color in the enhanced MU-RTS TXS trigger frame with their own Group BSS color. The Group BSS color matches, indicating that they are part of the same C-TDMA group. Next, STA11 and STA12 compare the BSS color in the user info field of the enhanced MU-RTS TXS trigger frame with their own BSS color. The BSS color does not match, suggesting that STA11 and STA12 are not associated with the shared AP (AP2). Consequently, STA11 and STA12 set the intra NAV to avoid interfering with the transmissions of the shared AP.

[0280] For STA21, both the Group BSS color and BSS color in the enhanced MU-RTS TXS trigger frame match its own colors. This indicates that STA21 is associated with the shared AP (AP2) and is part of the same C-TDMA group. As a result, STA21 does not set the basic NAV, as shown in FIG. 27, allowing it to participate in transmissions during the allocated time for AP2.

[0281] By comparing the Group BSS color and BSS color in the user info field, STAs can determine whether to set the intra NAV or not set the basic NAV. This enables efficient coordination and resource utilization within the C-TDMA scheme while ensuring that nonparticipating STAs follow the existing NAV rule.

[0282] FRAME EXCHANGE PROCEDURE EXAMPLE IN OBSS AND M-AP TOPOLOGY [0283] FIG. 28 illustrates an example of the frame exchange procedure when applying Option 3 or Option 4 in a scenario involving Overlapping Basic Service Set (OBSS) and Multiple Access Points (Multi-AP).

[0284] In the given context, Option 3 and Option 4 are approaches disclosed to handle coordination and resource allocation in a complex wireless network environment where multiple APs and their associated stations (STAs) coexist and overlap.

[0285] The frame exchange procedure depicted in FIG. 28 demonstrates how Option 3 and Option 4 facilitate communication and coordination among the APs and STAs in the presence of OBSS and Multi-AP scenarios.

[0286] FIG. 28 shows the sequence of frames exchanged between the APs and STAs, including control frames (such as RTS, CTS, or enhanced MU-RTS TXS) and data frames. FIG. 28 also highlights the specific actions taken by each AP and STA based on the applied solution, such as setting the appropriate Network Allocation Vector (NAV) values.

[0287] FIG. 28 provides a visual representation of how Option 3 and Option 4 operate in practice, enabling efficient coordination, resource allocation, and interference management in a complex wireless network environment with OBSS and Multi-AP scenarios.

[0288] FIG. 28 serves as a useful reference to understand the practical implementation and benefits of Option 3 and Option 4 in enhancing the performance and coordination of wireless networks in the presence of overlapping and multi-AP deployments.

[0289] In the prepare phase of C-TDMA, the shared AP informs the sharing AP about the amount of allocation time it requires. This allocation time is calculated by taking into account the possibility of retransmissions due to poor channel conditions. However, since channel conditions are unpredictable and can vary, there may be instances where the actual transmit/receive PPDUs (Physical Layer Protocol Data Units) are completed much earlier than the reported allocation time duration.

[0290] When the shared AP finishes its transmissions or receptions ahead of the allocated time, it may not be able to utilize the remaining allocated medium time effectively. This situation leads to a waste of resources, as the unused time could have been allocated to other APs or used for other purposes.

[0291] To address this issue, a mechanism disclosed herein leverages an enhanced MU-RTS TXS trigger frame. This enhanced frame allows the shared AP to return any unused time back to the sharing AP. By doing so, the sharing AP can efficiently reallocate the unused time to other APs or utilize it for its own transmissions, thereby minimizing resource wastage.

[0292] The proposed mechanism aims to optimize resource utilization in C-TDMA by enabling dynamic adjustment of allocation time based on actual channel conditions and transmission requirements. By allowing the shared AP to return unused time to the sharing AP, the overall efficiency of the C-TDMA system can be improved, leading to better utilization of available resources and enhanced network performance.

[0293] The passage describes a scenario where a shared Access Point (AP) in a Coordinated Time Division Multiple Access (C-TDMA) system can efficiently manage its allocated time and return any unused time to the sharing AP. This mechanism aims to reduce resource wastage and improve overall system throughput.

[0294] When the shared AP transmits or receives a BlockAck (BA) frame in an uplink/downlink (UL/DL) scenario, it may determine that the remaining allocation time is insufficient to initiate and complete a new UL/DL procedure. In such cases, the shared AP calculates the residual time, which is the difference between the initially allocated time (stored in the shared AP's buffer) and the end time of transmitting or receiving the last BA frame.

[0295] Additionally, there may be situations where the shared AP has no more data to transmit or receive. In these cases, the shared AP can also calculate the residual time.

[0296] The proposed mechanism allows the shared AP to convey the residual time in the allocation duration field of the enhanced MU-RTS TXS trigger frame when communicating with the sharing AP. By providing this information, the sharing AP can reclaim the unused time and resume its role as the TXOP holder earlier than originally scheduled. This early return of unused time helps reduce resource wastage.

[0297] RETRNING SHARED AP'S ALLOCATION TIME TO SHARING AP USING ENHANCED MU-RTS TXS FRAME

[0298] FIG. 29 illustrates an example frame exchange procedure that demonstrates how the shared AP returns unused time to the sharing AP. By implementing this mechanism, the C- TDMA system can optimize resource utilization and enhance overall system throughput.

[0299] The proposed approach addresses the issue of resource inefficiency that arises when the shared AP cannot fully utilize its allocated time due to insufficient time for new UL/DL procedures or the absence of additional data to transmit or receive. By dynamically calculating and returning the unused time to the sharing AP, the system can make better use of available resources and improve its performance. [0300] The enhanced MU-RTS TXS trigger frame is designed to address two main issues in C- TDMA: enabling uplink transmissions from stations (STAs) associated with the shared AP and efficiently returning unused time from the shared AP to the sharing AP.

[0301] By implementing the proposed frame, the STAs associated with the shared AP can transmit uplink packets without setting the basic Network Allocation Vector (NAV) from the sharing AP. The basic NAV is typically used to reserve the medium for a specific duration, preventing other devices from transmitting. However, in this case, the STAs associated with the shared AP can bypass the basic NAV and transmit their uplink packets, improving efficiency and reducing unnecessary waiting times.

[0302] Furthermore, the enhanced MU-RTS TXS trigger frame allows the shared AP to return any unused time to the sharing AP. In C-TDMA, the sharing AP allocates a specific time duration to the shared AP for its transmissions. If the shared AP completes its transmissions early or has no more data to send, it can use the proposed frame to inform the sharing AP about the unused time. The sharing AP can then reclaim this unused time and allocate it to other APs or use it for its own transmissions, thereby minimizing resource wastage.

[0303] By facilitating uplink transmissions from STAs associated with the shared AP and enabling the efficient return of unused time, the enhanced MU-RTS TXS trigger frame contributes to increased system throughput. It optimizes resource utilization, reduces wastage, and allows for more efficient communication in a Multi-AP C-TDMA scenario.

[0304] Overall, the proposed enhanced MU-RTS TXS trigger frame addresses key challenges in C-TDMA and provides a mechanism for improved coordination, resource allocation, and throughput enhancement in Multi-AP environments.

[0305] EXAMPLE METHODS

[0306] FIG. 30 illustrates a method 3000 for a sharing access point in a wireless network to allocate a portion of its transmit opportunity to a shared access point by generating and wirelessly transmitting a trigger frame, in accordance with some embodiments of the present disclosure.

[0307] The method 3000 involves a two-step process executed by a wireless device operating as a sharing access point (AP) within a wireless network, specifically designed to optimize the distribution of transmit opportunities (TXOPs) among various APs in dense network environments. This is particularly relevant in the context of advanced IEEE 802.11 standards such as 802.1 Ibe and thereafter, which require sophisticated coordination mechanisms to handle high data traffic efficiently. [0308] The first step involves generating 3002 a trigger frame, which is a special type of control frame that communicates specific transmission instructions to another AP (termed as the shared AP). The purpose of this trigger frame is to allocate a portion of the sharing AP's available TXOP to the shared AP. This allocation is useful in managing the network's overall traffic and ensuring that multiple APs can operate simultaneously without causing significant interference or congestion. To implement this step, the sharing AP can be equipped with firmware or software capable of assessing the current network conditions — such as the usage rates, channel availability, and interference levels — and then calculating the appropriate TXOP allocation for the shared AP. The trigger frame can include details such as the duration of the TXOP, the specific channels to be used, and the timing of the allocation.

[0309] Once the trigger frame is generated 3002, the next step is to transmit 3004 it wirelessly to the shared AP. This transmission must be conducted over the air using the communication protocols. The sharing AP can handle the modulation and encoding of the signal to ensure that the frame is transmitted clearly and received by the shared AP without errors. To ensure reliability and correct reception, the sharing AP may also implement acknowledgment mechanisms where the shared AP confirms receipt of the trigger frame. If the frame is not acknowledged, the sharing AP might have to retransmit the frame or adjust the transmission parameters to overcome any potential issues such as interference or signal degradation.

[0310] Together, these steps 3002 and 3004 form a method 3000 by which wireless networks, particularly those operating under the latest Wi-Fi standards, can enhance their efficiency and performance in high-density scenarios. This method 3000 facilitates a more intelligent distribution of network resources, ensuring that all APs within the network have adequate opportunities to transmit data, thereby optimizing the overall network throughput and reducing delays and packet losses.

[0311] FIG. 31 illustrates a method 3100 for a station associated with a sharing access point to receive a trigger frame indicating a transmit opportunity allocation to a shared access point, defer its uplink transmission until the allocated portion ends, and then wirelessly transmit the uplink data to the sharing access point, in accordance with some embodiments of the present disclosure.

[0312] The method 3100 focuses on how a wireless device operating as a station (STA) interacts with access points (APs) within a network to efficiently manage data transmissions, especially in environments with heavy traffic and multiple APs. This method 3100 is part of a broader system designed to optimize the use of transmit opportunities (TXOPs) in a way that minimizes collision and maximizes throughput. [0313] The first step involves the station receiving 3102 a trigger frame from a sharing access point. This trigger frame is specifically designed to communicate the allocation of a portion of the sharing AP’s TXOP to another AP, referred to as the shared AP. The frame may include information such as the duration of the allocation and the specific times at which the shared AP is authorized to transmit. Implementation may involve the station's wireless receiver being configured to recognize and process such trigger frames. This requires the receiver to monitor for frames and parse them to extract relevant information, such as the TXOP allocation duration and timing.

[0314] Upon receiving 3102 and processing the trigger frame, the station then determines 3104 to defer its own uplink data transmission to the sharing AP until after the allocated TXOP to the shared AP has concluded. This determination is based on the allocation duration specified in the trigger frame. The station's network controller, typically part of its firmware, will use this information to adjust its transmission schedule. This scheduling must be precise to avoid overlap with the TXOP allocated to the shared AP, thereby preventing data collision and ensuring efficient use of the network bandwidth.

[0315] Once the allocated TXOP to the shared AP ends, the station proceeds to transmit 3106 its deferred uplink data to the sharing AP. For this, the station to have a mechanism in place for tracking the time and ensuring that transmission begins precisely when the shared AP’s TXOP ends. The station may be configured to handle the physical layer transmission processes, including modulation and encoding. It can also ensure that the transmission is executed within the parameters set for effective communication, such as power levels and channel selection, to avoid interference and maximize transmission quality.

[0316] The effective implementation of these steps allows the station to contribute to the overall network efficiency, particularly in dense environments where the risk of data collision is high. By intelligently scheduling transmissions around the TXOPs allocated to other APs, the station helps maintain a smooth and coordinated flow of data across the network. This method 3100 may be particularly relevant in settings like corporate offices or public venues, where numerous devices and APs must coexist and operate without interfering with each other.

[0317] FIG. 32 illustrates a method 3200 for a shared access point to receive a trigger frame allocating a transmit opportunity portion from a sharing access point, determine the unused residual time, and generate and transmit a second trigger frame to return the unused portion back to the sharing access point, in accordance with some embodiments of the present disclosure. [0318] The method 3200 details how a wireless device, operating as a station associated with a shared access point (AP) in a wireless network, handles communication to optimize network resource use and minimize transmission conflicts. This approach is useful in networks where access points manage multiple transmissions and network traffic dynamically.

[0319] The first step involves the station receiving 3202 a trigger frame from a sharing access point. This trigger frame communicates the allocation of a portion of the sharing AP's transmit opportunity (TXOP) to the shared AP, which the station is associated with. The trigger frame contains data that helps the station understand when the shared AP has dedicated TXOP, allowing it to plan its transmissions accordingly.

[0320] The station's wireless receiver may be capable of identifying and decoding trigger frames. This may involve integrating capabilities into the station’s firmware or software to distinguish these specific frames from other types of data or management frames it receives. [0321] Once the trigger frame is received, the station may extract the necessary information about the TXOP allocation — specifically, the timing and duration of the TXOP granted to the shared AP.

[0322] The second step is where the station prevents 3204 the setting of its basic NAV during the TXOP allocated to the shared AP. The NAV is a mechanism used in wireless networking to indicate a period during which the station should refrain from initiating transmissions, typically to avoid collisions. By not setting the basic NAV, the station remains free to transmit uplink data to the shared AP even during the TXOP periods allocated to it.

[0323] To implement this, the station’s network management protocols may be modified to conditionally bypass setting the basic NAV when specific criteria (defined by the received trigger frame) are met. This may involve programming the station’s networking stack to recognize conditions under which it should keep the basic NAV unset.

[0324] The station may implement real-time decision-making processes to dynamically determine whether to set or bypass the basic NAV based on ongoing network conditions and the instructions received from the trigger frame. This ensures that the station can continue transmitting uplink data without unnecessary restrictions.

[0325] By following these steps, the station can effectively manage its transmission rights in a highly dynamic and potentially congested network environment, ensuring efficient utilization of available network resources and maintaining high throughput. This method 3200 may be particularly advantageous in dense network settings where the coordination of transmission opportunities significantly impacts overall network performance.

[0326] FIG. 33 illustrates a method 3300 for a shared access point to receive a trigger frame allocating a transmit opportunity portion from a sharing access point, determine the unused residual time, and generate and transmit a second trigger frame to return the unused portion back to the sharing access point, in accordance with some embodiments of the present disclosure. [0327] FIG. 33 outlines a method 3300 for a shared access point (AP) in a wireless network to manage and optimize the use of a transmit opportunity (TXOP) allocated by a sharing AP. This approach may be particularly effective in environments where multiple APs must coordinate their transmission times to maximize network efficiency and minimize overlap and congestion. The method 3300 encompasses of several steps.

[0328] The process begins when the shared AP receives 3302 a first trigger frame from a sharing AP. This frame the portion of the sharing AP's TXOP that is allocated to the shared AP, including the duration of this allocation. The shared AP may be equipped to receive and correctly interpret this trigger frame by ensuring that the shared AP’s wireless receiver is capable of identifying and decoding trigger frames and is capable of parsing the trigger frame to extract key details about the TXOP allocation, specifically the start time and duration.

[0329] After utilizing the allocated TXOP, the shared AP calculates 3304 the residual time, which is the unused portion of the TXOP that it did not use. This could be due to various operational efficiencies or less-than-anticipated data transmission needs. For this, the station may implement monitoring mechanisms to track the actual usage of the allocated TXOP. The station may calculate the residual time by subtracting the time used from the total time allocated. [0330] Using the calculated residual time, the shared AP then generates 3306 a second trigger frame. This new frame is intended to inform the sharing AP of the unused TXOP, allowing it to potentially reallocate this residual time either to the shared AP at a later interval, to another AP, or to its own stations. For this, the shared AP may be programmed to construct a trigger frame that includes the calculated residual time.

[0331] The final step involves wirelessly transmitting 3308 this second trigger frame back to the sharing AP. This transmission notifies the sharing AP of the returned unused TXOP, enabling it to manage its overall TXOP allocations more effectively. For this, the shared AP may use protocols for transmitting the frame, ensuring it is sent over the correct channel and with the appropriate power settings. Optionally, the shared AP may implement mechanisms to confirm that the sharing AP has received the second trigger frame, such as waiting for an acknowledgment signal.

[0332] This method allows for dynamic reallocation of network resources, ensuring that TXOPs are used efficiently across the network. It may be particularly beneficial in dense network environments where managing overlapping transmissions is crucial for maintaining high throughput and reducing interference. [0333] CONCLUSION

[0334] 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 convey the substance of their work most effectively 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.

[0335] 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.

[0336] 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 out the 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. [0337] 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.

[0338] 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.

[0339] 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

CLAIMS What is claimed is:

1. A method performed at a wireless device operating as a sharing access point in a wireless network, the method comprising: generating a trigger frame to allocate a portion of a transmit opportunity of the sharing access point to a shared access point in the wireless network; and wirelessly transmitting the trigger frame to the shared access point to allocate the portion of the transmit opportunity of the sharing access point to the shared access point.

2. The method of claim 1, wherein the trigger frame comprises a user information field, and wherein the user information field indicates at least one of: an identifier of the shared access point, an allocation duration for the portion of the transmit opportunity of the sharing access point to allocate to the shared access point, a group basic service set color, or a bound bit.

3. The method of claim 2, wherein the identifier of the shared access point comprises at least one of: a basic service set color for the shared access point, an access point identifier (AP- ID) for the shared access point, or an access point association identifier (AP AID) for the shared access point.

4. The method of claim 1, wherein the trigger frame comprises a triggered transmit opportunity sharing mode subfield encoding indicating that only the shared access point should send a clear-to-send response frame in response to receiving the trigger frame and not any stations associated with the shared access point that overhear the trigger frame.

5. The method of claim 1, wherein the trigger frame indicates a bound bit for determining how a station associated with the shared AP that overhears the trigger frame sets a network allocation vector; and wherein the bound bit is in a signal field, a common information field, or a user information field of the trigger frame.

6. A method performed by a wireless device operating as a station associated with a sharing access point in a wireless network, the method comprising: receiving a trigger frame sent by the sharing access point in the wireless network, the trigger frame sent by the sharing access point to allocate a portion of a transmit opportunity of the sharing access point to a shared access point in the wireless network, the trigger frame indicating an allocation duration for the portion of the transmit opportunity of the sharing access point to allocate to the shared access point; determining to defer an uplink data transmission to the sharing access point until after the portion of the transmit opportunity of the sharing access point allocated to the shared access point has ended; and wirelessly transmitting the uplink data transmission to the sharing access point after the portion of the transmit opportunity of the sharing access point allocated to the shared access point has ended.

7. The method of claim 6, further comprising: determining that a bound bit of the trigger frame is set; comparing a basic service set color of a signal field of the trigger frame to a basic service set color for the station; determining that the basic service set color of the signal field of the trigger frame matches the basic service set color for the station; and setting an intra network allocation vector at the station.

8. The method of claim 6, further comprising: determining that a bound bit of the trigger frame is set; comparing a basic service set color of a user information field of the trigger frame to a basic service set color for the station; determining that the basic service set color of the user information field of the trigger frame does not match the basic service set color for the station; and setting an intra network allocation vector at the station.

9. The method of claim 6, further comprising: comparing a group basic service set color of the trigger frame to a predefined basic service set color for the station; determining that the group basic service set color of the trigger frame matches the predefined basic service set color for the station; comparing a basic service set color of a signal field of the trigger frame to a basic service set color for the station; determining that the basic service set color of the signal field of the trigger frame matches the basic service set color for the station; and setting an intra network allocation vector at the station.

10. The method of claim 6, further comprising: comparing a group basic service set color of the trigger frame to a predefined basic service set color for the station; determining that the group basic service set color of the trigger frame matches the predefined basic service set color for the station; comparing a basic service set color of a user information field of the trigger frame to a basic service set color for the station; determining that the basic service set color of the user information field of the trigger frame does not match the basic service set color for the station; and setting an intra network allocation vector at the station.

11. A method performed by a wireless device operating as a station associated with a shared access point in a wireless network, the method comprising: receiving a trigger frame sent by a sharing access point in the wireless network, the trigger frame sent by the sharing access point to allocate a portion of a transmit opportunity of the sharing access point to the shared access point; and preventing the station from setting a basic network allocation vector at the station so that the station is not restricted from transmitting uplink data to the shared access point during the portion of the transmit opportunity allocated to the shared access point.

12. The method of claim 11, further comprising: determining that a bound bit of the trigger frame is set; comparing a basic service set color of a signal field of the trigger frame to a basic service set color for the station; and determining that the basic service set color of the signal field of the trigger frame does not match the basic service set color for the station.

13. The method of claim 11, further comprising: determining that a bound bit of the trigger frame is set; comparing a basic service set color of a user information field of the trigger frame to a basic service set color for the station; and determining that the basic service set color of the user information field of the trigger frame matches the basic service set color for the station.

14. The method of claim 11, further comprising: comparing a group basic service set color of the trigger frame to a predefined basic service set color for the station; determining that the group basic service set color of the trigger frame matches the predefined basic service set color for the station; comparing a basic service set color of a signal field of the trigger frame to a basic service set color for the station; and determining that the basic service set color of the signal field of the trigger frame does not match the basic service set color for the station.

15. The method of claim 11, further comprising: comparing a group basic service set color of the trigger frame to a predefined basic service set color for the station; determining that the group basic service set color of the trigger frame matches the predefined basic service set color for the station; comparing a basic service set color of a user information field of the trigger frame to a basic service set color for the station; and determining that the basic service set color of the user information field of the trigger frame matches the basic service set color for the station.

16. A method performed by a shared access point in a wireless network, the method comprising: receiving a first trigger frame sent by a sharing access point in the wireless network to allocate a portion of a transmit opportunity of the sharing access point to the shared access point, the first trigger frame indicating an allocation duration for the portion of the transmit opportunity of the sharing access point to allocate to the shared access point; determining a residual time reflecting a remaining unused portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point; generating a second trigger frame to return to the sharing access point the remaining unused portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point, the second trigger frame indicating the residual time; and wirelessly transmitting the second trigger frame to the sharing access point to return to the sharing access point the remaining unused portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point.

17. The method of claim 16, further comprising: determining the residual time based on the allocation duration indicated in the first trigger frame and an end time of a transmit or a receive of a block acknowledge frame.

18. The method of claim 16, further comprising: cascading, to one or more stations associated with the shared access point, at least a portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point.

19. The method of claim 16, further comprising: using at least a portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point to transmit data to a station associated with the shared access point.

20. The method of claim 16, further comprising: using at least a portion of the portion of the transmit opportunity of the sharing access point allocated to the shared access point to receive data from a station associated with the shared access point.

21. A wireless device to function as a sharing access point in a wireless network, the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a set of one or more processors coupled to the memory device, wherein the set of instructions, when executed by one or more processors of the set of one or more processors, causes the sharing access point to perform a method as recited in any one of claims 1-5.

22. A wireless device to function as a station associated with a sharing access point in a wireless network, the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a set of one or more processors coupled to the memory device, wherein the set of instructions, when executed by one or more processors of the set of one or more processors, causes the station to perform a method as recited any one of claims 6- 10.

23. A wireless device to function as a station associated with a shared access point in a wireless network, the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a set of one or more processors coupled to the memory device, wherein the set of instructions, when executed by one or more processors of the set of one or more processors, causes the station to perform a method as recited in any one of claims 11-15.

24. A wireless device to function as a shared access point in a wireless network, the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a set of one or more processors coupled to the memory device, wherein the set of instructions, when executed by one or more processors of the set of one or more processors, causes the shared to perform a method as recited in any one of claims 16-20.