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WO2024238201A2 - Partage d'opportunité de transmission amélioré avec transmission à accès multiple par répartition en temps coordonné - Google Patents

Partage d'opportunité de transmission amélioré avec transmission à accès multiple par répartition en temps coordonné Download PDF

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Publication number
WO2024238201A2
WO2024238201A2 PCT/US2024/028117 US2024028117W WO2024238201A2 WO 2024238201 A2 WO2024238201 A2 WO 2024238201A2 US 2024028117 W US2024028117 W US 2024028117W WO 2024238201 A2 WO2024238201 A2 WO 2024238201A2
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Prior art keywords
access point
trigger frame
basic service
station
service set
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WO2024238201A3 (fr
Inventor
Si-Chan NOH
Joonsoo Lee
Heejung Yu
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Newracom Inc
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Newracom Inc
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Publication of WO2024238201A3 publication Critical patent/WO2024238201A3/fr
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H04W74/0816—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA] with collision avoidance
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H04W74/006—Transmission of channel access control information in the downlink, i.e. towards the terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present disclosure generally relates to wireless communications, and more specifically, relates to enhanced transmit opportunity sharing with coordinated-time division multiple access transmission.
  • 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.
  • 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.
  • 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.
  • MLO multi-link operation
  • 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.
  • MAC medium access control
  • 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.
  • Gbps gigabits per second
  • 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.
  • 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.
  • FIG. 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.
  • FIG. 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.
  • FIG. 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.
  • FIG. 4 illustrates inter-frame space relationships, in accordance with some embodiments of the present disclosure.
  • FIG. 5 illustrates a carrier sense multiple access/collision avoidance-based frame transmission procedure, in accordance with some embodiments of the present disclosure.
  • FIG. 6 is a table of various characteristics of several wireless networking standards, in accordance with some embodiments of the present disclosure.
  • 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.
  • 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.
  • 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.
  • 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.
  • UHR Ultra High Reliability
  • 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.
  • C-TDMA Coordinated Time Division Multiple Access
  • 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.
  • NAV Network Allocation Vector
  • 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.
  • 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.
  • 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.
  • 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.
  • FIG. 17 illustrates an example of a frame exchange sequence, in accordance with some embodiments of the present disclosure.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • OBSS Overlapping Basic Service Sets
  • 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.
  • 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.
  • FIG. 27 illustrates an example snapshot of the NAV setting when applying the disclosed solution, in accordance with some embodiments of the present disclosure.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the present disclosure generally relates to wireless communications, and more specifically, relates to enhanced transmit opportunity sharing with coordinated-time division multiple access transmission.
  • the current IEEE 802.11 standard faces challenges in efficiently implementing Coordinated-Time Division Multiple Access (C-TDMA) schemes in high-density network scenarios.
  • C-TDMA Coordinated-Time Division Multiple Access
  • APs Access Points
  • APs participate in C-TDMA
  • they require a mechanism to share information and solicit C-TDMA between APs.
  • Another issue arises from the unintentional Network Allocation Vector (NAV) setting at the stations (STAs) associated with the shared AP.
  • NAV Network Allocation Vector
  • MU-RTS TXS Multi-User Request-to-Send Transmit Opportunity Sharing
  • 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.
  • NAV Network Allocation Vector
  • 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).
  • BSS Basic Service Sets
  • 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.
  • PPDU Physical Layer Protocol Data Unit
  • the sharing AP 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.
  • TXOP represents a time duration during which an AP has the right to initiate wireless transmissions.
  • 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.
  • 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.
  • the shared AP 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.
  • 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.
  • a method is performed by a wireless device operating as a station (STA) associated with a sharing access point (AP) in a wireless network.
  • 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.
  • the STA 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.
  • 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.
  • the STA By deferring its uplink transmission, the STA avoids interfering with the wireless transmissions of the shared AP during its allocated TXOP portion.
  • 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.
  • the STA 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.
  • 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.
  • the STA helps to minimize interference and promote fair access to the wireless medium.
  • a method is performed by a wireless device functioning as a station (STA) associated with a shared access point (AP) in a wireless network.
  • 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.
  • TXOP transmit opportunity
  • 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.
  • the STA 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.
  • the STA takes action to prevent itself from setting a basic network allocation vector (NAV).
  • NAV basic network allocation vector
  • 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.
  • 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.
  • 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.
  • 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.
  • a method is performed by a shared access point (AP) in a wireless network.
  • 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.
  • the shared AP 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.
  • 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.
  • the shared AP 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.
  • the shared AP wirelessly transmits the second trigger frame to the sharing AP.
  • the shared AP effectively returns the remaining unused portion of the allocated TXOP back to the sharing AP.
  • 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.
  • the shared AP helps to optimize the overall utilization of the wireless medium and promotes efficient resource allocation in the wireless network.
  • IEEE Institute of Electrical and Electronics Engineers
  • 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).
  • MAC medium access control
  • PHY physical
  • 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.
  • TXVECTOR specifies parameters for generating and/or transmitting the corresponding frame.
  • 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.
  • 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.”
  • AP STA access point station
  • non-AP STAs wireless devices 104B1-104B4 that function as non-access point stations
  • FIG. 2 presents a schematic block diagram of a wireless device 104, according to an embodiment.
  • the 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.
  • 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.
  • MAC medium access control
  • PHY physical
  • memory 232 can be a non-transitory computer-readable medium containing software (e.g., programmable instructions) and data.
  • 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.
  • the MAC hardware processing unit 216 realizes a second set of MAC layer functions through specialized hardware.
  • 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.
  • 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.
  • TX transmitting
  • RX receiving
  • PHY physical
  • 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.
  • FEC forward error correction
  • 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.
  • 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.
  • first information information received from the baseband processor 210
  • WLAN wireless local area network
  • second information received from the WLAN 100 (for example, from another wireless device 104 of the WLAN 100) back to the baseband processor 210.
  • the antenna unit 250 comprises one or more antennas.
  • 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.
  • 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.
  • the output interfaces 236 may include one or more of the following: a display device, touchscreen, speaker, among others.
  • WLAN wireless local area network
  • 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.
  • 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.
  • TX transmitting
  • SPU signal processing unit
  • RF radio frequency
  • 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.
  • the TxSPU 324 comprises an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer 306, and a guard interval inserter 308.
  • Encoder 300 receives input data and encodes it.
  • the encoder 300 features a forward error correction (FEC) encoder, which may consist of a binary convolutional code encoder followed by a puncturing device.
  • FEC encoder may utilize a low-density parity-check encoder.
  • 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.
  • 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.
  • 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.
  • Mapper 304 converts the sequence of bits output from the interleaver 302 into constellation points.
  • the mapper 304 may additionally execute low-density parity-check tone mapping, alongside constellation mapping.
  • the TxSP 324 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.
  • MIMO multiple-input, multiple-output
  • MU-MIMO multiuser multiple-input, multiple-output
  • 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.
  • MIMO multiple-input, multiple-output
  • MU-MIMO multi-user multiple-input, multiple-output
  • a dedicated inverse Fourier transform 306 may be provided for each transmit chain.
  • 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.
  • MIMO multiple-input, multiple-output
  • MU-MIMO multi-user multiple-input, multipleoutput
  • 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.
  • the TxSP 324 can apply windowing to each symbol postguard interval insertion to smooth out the symbol edges.
  • the RF transmitter 342 converts the baseband symbols into a radio frequency (RF) signal and then transmits this RF signal through antenna 352.
  • RF radio frequency
  • both the guard interval inserter 308 and the RF transmitter 342 are configured for each individual transmit chain.
  • 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.
  • 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.
  • 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.
  • 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.
  • MIMO multiple-input, multipleoutput
  • MU-MIMO multi-user multiple-input, multiple-output
  • the RF receiver 344 and the guard interval remover 318 may be allocated for each receive chain.
  • 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).
  • DFT discrete Fourier transform
  • FFT fast Fourier transform
  • 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.
  • 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.
  • 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.
  • 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.
  • the decoder 310 processes the streams emanating from either deinterleaver 312 or the stream deparser.
  • the decoder 310 is equipped with a forward error correction (FEC) decoder.
  • FEC decoder can be configured as either a binary convolutional code decoder or a low-density parity-check decoder.
  • 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.
  • wireless devices 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.
  • 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).
  • OFDM Orthogonal Frequency Division Multiplexing
  • OFDMA Orthogonal Frequency Division Multiple Access
  • a station such as wireless device 104, can transmit and receive PHY Protocol Data Units (PPDUs) in accordance with the mandatory PHY specifications.
  • PPDUs PHY Protocol Data Units
  • 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.
  • L-SIG Legacy Signal
  • SIG-A Signal A
  • SIG-B Signal B
  • PSDU PHY Service Data Unit
  • FIG. 4 illustrates the relationships among Inter-Frame Spaces (IFSs), s featuring 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.
  • WLAN wireless local area network
  • 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.
  • 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.
  • 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.
  • SIFS Short Inter-Frame Space
  • a wireless local area network (WLAN) device 104 equipped with quality of service (QoS) capabilities 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.
  • QoS STA quality of service
  • data frames, management frames, and control frames can utilize the AIFSfAC] designated for the AC of the frame being transmitted.
  • 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.
  • DIFS Distributed Coordination Function Inter-Frame Space
  • EIFS Extended Inter-Frame Space
  • the wireless local area network (WLAN) device 104 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.
  • DIFS Distributed Coordination Function Inter-Frame Space
  • EIFS Extended Inter-Frame Space
  • 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.
  • WLAN wireless local area network
  • 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.
  • NAV Network Allocation Vector
  • the station STA1 may transmit a Request-To-Send (RTS) frame to station STA2.
  • RTS Request-To-Send
  • station STA2 may transmit a Clear-To-Send (CTS) frame in response.
  • CTS Clear-To-Send
  • 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.
  • station STA3 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.
  • NAV Network Allocation Vector
  • station STA1 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.
  • 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.
  • 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.
  • STBC Space Time Block Coding
  • 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.
  • 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.
  • WLAN wireless local area network
  • GHz gigahertz
  • different candidate features 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.
  • MIMO multipleinput, multiple-output
  • HARQ Hybrid Automatic Repeat Request
  • 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.
  • 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
  • EHT Extremely High Throughput
  • channel access networks such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area networks (WLANs)
  • IEEE Institute of Electrical and Electronics Engineers
  • WLANs wireless local area networks
  • the physical carrier sense of one station is responsible for detecting the transmissions of other stations.
  • NAV network allocation vector
  • 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.
  • 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.
  • 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.
  • MAC medium access control
  • the receiver discards the last failed MPDU before receiving the newly retransmitted one.
  • ARQ automatic repeat request
  • HARQ processing There are two methods of HARQ processing.
  • 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.
  • FEC forward error correction
  • MRC maximum-ratio combining
  • WLAN wireless local area network
  • the information sequences are usually transmitted in packets with a fixed length.
  • 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.
  • 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.
  • IR Incremental Redundancy
  • 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).
  • SPID Subpacket Identity
  • 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.
  • subpacket SPIDs to be transmitted are in increasing order but can be exchanged except for the first SPID.
  • WLAN wireless local area network
  • 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.
  • 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.
  • joint access point tech multiple access points are transmitting jointly to a given user.
  • 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.
  • a non- transitory machine-readable medium such as microelectronic memory
  • processor data processing components
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • C-TDMA stands out as effective in terms of fairness, making it a promising candidate for future Wi-Fi standards.
  • C-TDMA technology offers several advantages in multi -access point (M-AP) scenarios.
  • M-AP multi -access point
  • C-TDMA provides an opportunity for channel access.
  • C-TDMA eliminates the need for CSI feedback.
  • C-TDMA has a simpler implementation compared to JTX technology, particularly in terms of mitigating synchronization issues between APs.
  • it is useful to share control information among APs.
  • 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.
  • 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.
  • 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.
  • BSS Color is an extension of the "BSS Color” mechanism introduced in IEEE 802.1 lax (Wi-Fi 6).
  • 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.
  • BSS Basic Service Set
  • 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.
  • 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.
  • BSS Basic Service Set
  • the Bound subfield 814 is related to the Network Allocation Vector (NAV) setting and has two possible options, both using a single bit.
  • NAV Network Allocation Vector
  • Option 1 focuses on the BSS color in the PHY preamble signal field of the enhanced MU-RTS TXS trigger frame.
  • the Bound field bit 814 is set to 1
  • the receiving device sets the intra NAV.
  • the Bound field bit 814 is set to 0, it is reserved for future use.
  • 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.
  • 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.
  • 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.
  • 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).
  • Encoding 00 This indicates that triggered TXOP sharing is disabled or not supported by the device.
  • 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.
  • 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.
  • Encoding 11 This value is reserved for future use or extensions to the triggered TXOP sharing modes.
  • the purpose of this subfield is to facilitate efficient TXOP sharing among devices in a wireless network.
  • devices can coordinate and manage their TXOP usage more effectively, leading to improved network performance and resource utilization.
  • FIG. 10 provides a table of the new mode of TXOP sharing between APs.
  • M-AP Multi-AP
  • C-TDMA Coordinated Time Division Multiple Access
  • C-OFDMA Coordinated Orthogonal Frequency Division Multiple Access
  • a scheduled AP 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.
  • the scheduled AP can transmit one or more MAC Protocol Data Units (MPDUs) addressed to a participating AP, which is typically an associated AP.
  • MPDUs MAC Protocol Data Units
  • the “scheduled” AP is the sharing AP that obtains the TXOP.
  • 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.
  • 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.
  • the scheduled AP can allocate specific time slots to the participating AP, enabling it to transmit during its assigned time slots without contention.
  • the scheduled AP can allocate specific frequency resources to the participating AP, allowing it to transmit on its assigned subcarriers.
  • 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.
  • the new mode dictates a specific response mechanism.
  • the shared AP is responsible for sending a CTS (Clear to Send) frame in response to the received enhanced MU-RTS TXS trigger frame.
  • CTS Charge to Send
  • 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.
  • the sharing AP transmits an enhanced MU-RTS TXS trigger frame to the shared AP.
  • STAs stations
  • NAV Network Allocation Vector
  • the basic NAV is a mechanism used to prevent STAs from accessing the medium during a reserved transmission period.
  • 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.
  • 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.
  • FIG. 11 illustrates the topology of the APs and STAs involved in the Coordinated-Time Division Multiple Access (C-TDMA) scheme.
  • C-TDMA Coordinated-Time Division Multiple Access
  • API successfully occupies the channel during the prepare phase, which is a preliminary stage in the C-TDMA process.
  • 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.
  • TXOP Transmit Opportunity
  • AP2 which is the other AP involved in the C-TDMA setup, becomes 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.
  • API sharing AP
  • 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.
  • NAV Network Allocation Vector
  • STA21 which is associated with AP2, sets its basic NAV according to the enhanced MU-RTS TXS trigger frame received from API.
  • 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.
  • 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.
  • BSS Basic Service Set
  • 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.
  • the enhanced MU-RTS TXS trigger frame includes a duration field that specifies the allocation duration time to be shared with AP2.
  • STA11 which is associated with API, is prevented from attempting to occupy the channel during AP2's allocation time.
  • 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).
  • BSS Basic Service Set
  • an STA 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.
  • the PHY preamble signal field e.g., UHR SIG field or future standard SIG field
  • 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.
  • 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.
  • STAs stations
  • the Bound bit field value is set to 1 in the enhanced MU-RTS TXS frame.
  • 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).
  • MyBSS color BSS color
  • the BSS color in the PHY preamble is designed to be API's BSS color.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the system provides flexibility in implementing the NAV setting mechanism based on the specific requirements and constraints of the wireless network.
  • 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).
  • an STA 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.
  • the STA 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • STAs can determine their association with the shared AP and set the NAV accordingly.
  • 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).
  • M-APs multiple access points
  • C-TDMA Coordinated Time Division Multiple Access
  • 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.
  • TXOP transmission opportunity
  • 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.
  • BSS Basic Service Set
  • the sharing of BSS colors is useful for the option of Option 1 and Option 2.
  • 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.
  • NAV Network Allocation Vector
  • 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.
  • MyBSS color BSS color
  • 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.
  • STAs 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.
  • 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.
  • 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.
  • group BSS color is a 1-3 bit field that identifies the group of stations and access points participating in a Multi-AP scheme.
  • an STA 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • FIG. 18, FIG. 19, and FIG. 20 illustrate possible locations of the Group BSS color field within the enhanced MU-RTS TXS trigger frame.
  • FIG. 18, FIG. 19, and FIG. 20 illustrate possible locations of the Group BSS color field within the enhanced MU-RTS TXS trigger frame.
  • Three different frame structures 1800, 1900, and 2000 are presented, each showcasing a different placement of the Group BSS color field:
  • 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.
  • 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.
  • 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.
  • 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.
  • the placement of the Group BSS color field in different parts of the frame 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.
  • 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.
  • STAs 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.
  • 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.
  • the STAs do not set the basic NAV, allowing them to transmit during the allocated time for their associated AP.
  • the STAs set the intra-NAV, indicating that they should refrain from transmitting during the allocated time.
  • 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.
  • 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.
  • 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.
  • the STA sets the intra-NAV, indicating that it should refrain from transmitting during the allocated time.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • C-TDMA Coordinated Time Division Multiple Access
  • 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.
  • 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.
  • AP2 can efficiently deliver data to the STAs without contention from other APs or STAs.
  • 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.
  • FIG. 24 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.
  • OBSS Overlapping Basic Service Set
  • 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.
  • 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.
  • BSS Basic Service Set
  • 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.
  • 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.
  • 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.
  • OBSS Overlapping Basic Service Set
  • C-TDMA Coordinated Time Division Multiple Access
  • FIG. 26 shows the NAV setting when multiple APs (API and AP3) are involved in C- TDMA coordination.
  • 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.
  • STA31 could overhear the enhanced MU-RTS TXS trigger frame transmitted from API to AP3.
  • 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.
  • STA31 follows the existing Network Allocation Vector (NAV) rule and sets the basic NAV, as indicated in FIG. 27.
  • NAV Network Allocation Vector
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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).
  • OBSS Basic Service Set
  • Multi-AP Multiple Access Points
  • 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.
  • 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.
  • 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.
  • control frames such as RTS, CTS, or enhanced MU-RTS TXS
  • data frames such as 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.
  • NAV Network Allocation Vector
  • 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.
  • 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.
  • 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.
  • PPDUs Physical Layer Protocol Data Units
  • 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.
  • 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.
  • 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.
  • the shared AP 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.
  • BA BlockAck
  • the shared AP may also calculate the residual time.
  • 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.
  • 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.
  • FIG. 29 illustrates an example frame exchange procedure that demonstrates how the shared AP returns unused time to the sharing AP.
  • 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.
  • 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.
  • 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.
  • the STAs associated with the shared AP can bypass the basic NAV and transmit their uplink packets, improving efficiency and reducing unnecessary waiting times.
  • the enhanced MU-RTS TXS trigger frame allows the shared AP to return any unused time to the sharing AP.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the station 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.
  • the station proceeds to transmit 3106 its deferred uplink data to the sharing AP.
  • 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.
  • 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.
  • 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.
  • AP shared access point
  • 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.
  • TXOP transmit opportunity
  • the trigger frame contains data that helps the station understand when the shared AP has dedicated TXOP, allowing it to plan its transmissions accordingly.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the shared AP uses the calculated residual time to generate 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.
  • the shared AP may be programmed to construct a trigger frame that includes the calculated residual time.
  • 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.
  • the shared AP may use protocols for transmitting the frame, ensuring it is sent over the correct channel and with the appropriate power settings.
  • 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.
  • 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.
  • 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.
  • ROMs read-only memories
  • RAMs random access memories
  • EPROMs electrically erasable programmable read-only memories
  • EEPROMs electrically erasable programmable read-only memories
  • magnetic or optical cards or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.
  • 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).
  • 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.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Une trame de déclenchement de TXS MU-RTS améliorée pour permettre des mécanismes C-TDMA efficaces entre des AP. La trame améliorée résout les défis concernant la mise en œuvre de schémas C-TDMA dans des scénarios de réseau haute densité au-delà de IEEE 802.11be, comme le gaspillage de ressources en raison d'un temps de partage TXOP attribué et d'un réglage NAV non intentionnel au niveau de STA associées à l'AP partagé. La trame de déclenchement de TXS MU-RTS améliorée permet à un AP d'attribuer une partie de sa TXOP obtenue à d'autres AP, atténue le problème de gaspillage de ressources, et fournit un moyen pour gérer l'ensemble de NAV de base par l'AP de partage au niveau des STA associées à l'AP partagé. La trame est applicable à d'autres schémas multi-AP, gérant des problèmes NAV provenant d'un autre BSS. Il permet également à un AP partagé de renvoyer un temps d'attribution partagé inutilisé à l'AP de partage, permettant à l'AP de partage de reprendre des transmissions PPDU normales plus tôt dans la TXOP restante, augmentant finalement le débit du système.
PCT/US2024/028117 2023-05-16 2024-05-07 Partage d'opportunité de transmission amélioré avec transmission à accès multiple par répartition en temps coordonné Pending WO2024238201A2 (fr)

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US63/504,402 2023-05-25

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KR20230074296A (ko) * 2015-06-29 2023-05-26 주식회사 윌러스표준기술연구소 데이터 전송을 위한 채널 접근 방법, 이를 이용한 무선 통신 방법 및 무선 통신 단말
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