Multi-link operation (MLO) relay supportability in wireless networks

Abstract

An embodiment is a method performed by a station (STA) that has multi-link operation (MLO) capability to provide MLO relay supportability information to an access point (AP). The method includes detecting a change in a MLO relay supportability type for the STA from a previous MLO relay supportability type for the STA to a current MLO relay supportability type for the STA, responsive to detecting the change, transmitting a relay supportability update request message to the AP that includes updated MLO relay supportability information for the STA, and receiving, as a response to the relay supportability update request message, a relay supportability update response message from the AP indicating that the AP has stored the updated MLO relay supportability information for the STA.

Description

SPECIFICATIONMULTI-LINK OPERATION (MLO) RELAY SUPPORTABILITY IN WIRELESS NETWORKSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 555,846, filed February 20, 2024, titled “Classification and Reporting the Relay Supportability in MultiLink Operation Wireless LAN Systems”, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to multi-link operation (MLO) relay supportability in wireless networks.BACKGROUND

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

[0004] IEEE 802.1 Ibe, also known as “Wi-Fi 7”, is the next generation of the IEEE 802.11 family of standards for wireless local area networks. IEEE 802.1 Ibe aims to significantly improve upon the capabilities of its predecessor, 802.1 lax / Wi-Fi 6, by offering even higher data rates, lower latency, and increased reliability. The standard is expected to leverage advanced technologies such as multi-link operation (MLO), which allows devices to simultaneously use multiple frequency bands and channels for enhanced performance and reliability.Additionally, 802.1 Ibe will introduce 4096-QAM (Quadrature Amplitude Modulation), enablinghigher data rates by encoding more bits per symbol. The standard will also feature improved medium access control (MAC) efficiency, enhanced power saving capabilities, and better support for high-density environments. With these advancements, IEEE 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.

[0005] IEEE 802.11 wireless local area networks (WLANs) have become integral to daily activities and there has been a growing need to expand network coverage to reach areas with challenging topologies, large physical spaces, and / or high user densities. While WLANs offer significant mobility and convenience for users, they also have limitations in terms of coverage and reliability. Relay operations have been considered as a way to extend the coverage and enhance the reliability of WLANs. The use of relay operations may increase coverage, mitigate connectivity challenges, and / or increase network performance by having strategically deployed intermediary devices that can facilitate communication between distant devices.

[0006] IEEE 802.1 Is, also referred to as WLAN Mesh, introduces mesh networking capabilities to traditional Wi-Fi networks. Mesh networks consist of interconnected devices, typically APs, that coordinate with each other to extend network coverage and enhance reliability. Unlike conventional Wi-Fi setups where devices communicate directly with a central AP, IEEE 802.1 Is allows for dynamic routing through multiple devices, creating a self-forming and self-healing network. The mesh architecture provides enhanced coverage and resilience in challenging environments and may be particularly advantageous in scenarios where the deployment of a traditional infrastructure is impractical.

[0007] IEEE 802.1 lad, also referred to as WiGig, operates in the 60 GHz frequency band, aiming to deliver high-speed short-range wireless communication. Unlike previousIEEE 802.11 wireless networking standards, 802. Had focuses on enabling multi-gigabit data rates, making it suitable for applications requiring rapid data transfer such as high-definition video streaming. IEEE 802.1 lad employs directional beamforming to allow devices to establish focused communication links for increased efficiency. The high data rates and directional communication capabilities of IEEE 802.1 lad contribute to improved overall network performance, particularly in short-range communication scenarios.

[0008] The emerging IEEE 802.1 Ibe wireless networking standard builds upon the foundation of its predecessors and introduces a feature known as multi-link operation (MLO). MLO- capable devices may transmit and receive traffic over multiple wireless links using multiple wireless interfaces to achieve higher throughput rates and lower latency.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The disclosure will be more fully understood from the detailed description provided below and the accompanying drawings that depict various embodiments of the disclosure. However, these drawings should not be interpreted as limiting the disclosure to the specific embodiments shown; they are provided for explanation and understanding only.

[0010] Figure 1 illustrates an example of a wireless local area network (WLAN) with a basic service set (BSS) that includes multiple wireless devices, in accordance with some embodiments of the present disclosure.

[0011] Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

[0012] Figure 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.

[0013] Figure 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.

[0014] Figure 4 illustrates interframe space (IFS) relationships, in accordance with some embodiments of the present disclosure.

[0015] Figure 5 illustrates a Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA)-based frame transmission procedure, in accordance with some embodiments of the present disclosure.

[0016] Figure 6 illustrates maximum physical layer (PHY) rates for Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, in accordance with some embodiments of the present disclosure.

[0017] Figure 7 provides a detailed description of fields in Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) frames, including their purposes and characteristics, in accordance with some embodiments of the present disclosure.

[0018] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency -Di vision Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0019] Figure 9 illustrates an example of an access point sending a trigger frame to multiple associated stations and receiving Uplink Orthogonal Frequency -Division Multiple Access Trigger-Based Physical Protocol Data Units (UL OFDMA TB PPDUs) in response, in accordance with some embodiments of the present disclosure.

[0020] Figure 10 is a diagram showing a wireless network environment with an access point (AP), relay stations (STAs), and STAs that are capable of multi-link operation (MLO) in a 2.4 Gigahertz (GHz) band and a 5 GHz band, according to some embodiments.

[0021] Figure 11 is a diagram showing a single link operation and a multi-link operation between an AP and a non-AP STA, according to some embodiments.

[0022] Figure 12 is a diagram showing a relay STA multi-link device (MLD) that can relay communications between an AP multi-link device (MLD) and a non-AP STA MLD using MLO, according to some embodiments.

[0023] Figure 13 is a diagram showing a table of MLO relay supportability types, according to some embodiments.

[0024] Figure 14 is a diagram showing a table summarizing the types of communications available for each MLO relay supportability type, according to some embodiments.

[0025] Figure 15 is a diagram showing MLO relay supportability type #1, according to some embodiments.

[0026] Figure 16 is a diagram showing MLO relay supportability type #2, according to some embodiments.

[0027] Figure 17 is a diagram showing MLO relay supportability type #3, according to some embodiments.

[0028] Figure 18 is a diagram showing MLO relay supportability type #4, according to some embodiments.

[0029] Figure 19 is a diagram showing a non-AP STA MLD that includes a MLD link status monitoring component, according to some embodiments.

[0030] Figure 20 is a flow diagram showing a method for determining a MLO relay supportability type, according to some embodiments.

[0031] Figure 21 is a diagram showing a frame exchange sequence for a non-AP STA to provide MLO relay supportability information to an AP via a relay STA, according to some embodiments.

[0032] Figure 22 is a diagram showing a frame exchange sequence for an AP to determine link quality and determine whether the MLO relay supportability type for a STA should be changed, according to some embodiments.

[0033] Figure 23 is a diagram showing a frame exchange sequence for a non-AP STA to provide MLO relay supportability information to an AP directly, according to some embodiments.

[0034] Figure 24 is a diagram showing a relay supportability information element, according to some embodiments.

[0035] Figure 25 is a diagram showing changes in the MLO relay supportability type for a STA, according to some embodiments.

[0036] Figure 26 is a flow diagram of a method for providing MLO relay supportability information, according to some embodiments.

[0037] Figure 27 is a flow diagram of a method for obtaining MLO relay supportability information, according to some embodiments.

[0038] Figure 28 is a flow diagram of a method for providing link quality information, according to some embodiments.

[0039] Figure 29 is a flow diagram of a method for determining that a MLO relay supportability type for a STA should be changed, according to some embodiments.DETAILED DESCRIPTION

[0040] The present disclosure generally relates to wireless communications, and more specifically, relates to multi-link operation (MLO) relay supportability in wireless networks.

[0041] As mentioned above relay operations have been considered as a way to extend the coverage and enhance the reliability of wireless local area networks (WLANs). Also, Institute of Electrical and Electronics Engineers (IEEE) 802.1 Ibe is introducing a feature called multilink operation (MLO) to allow MLO-capable devices to transmit and receive traffic over multiple wireless links. However, the use of relay operations with MLO-capable devices has not been considered.

[0042] MLO-capable devices may use relay technology to increase coverage and enhance reliability. A station (STA) that has MLO capability may communicate with an access point (AP) over multiple links operating in multiple channels / bands, with or without the use of relay operations. For example, assuming that the STA is capable of communicating in a first channel (e.g., a channel in the 2.4 Gigahertz (GHz) band) and a second channel (e.g., a channel in the 5 GHz band), the STA may communicate with the AP directly (without the use of relay operations) in the first channel, communicate with the AP directly (without the use of relay operations) in the second channel, communicate with the AP using relay operations in the first channel, and / or communicate with the AP using relay operations in the second channel. Also, relay operations may be used in the uplink direction and / or the downlink direction. The relay operations that are supported (or not supported) for a STA’s communication with an AP may change over time depending on the network situation (e.g., depending on the STA’s proximity tothe AP and / or channel conditions). The relay operations that are supported (or not supported) for a STA’s communication with an AP may generally be referred to herein as the STA’s MLO relay supportability.

[0043] The present disclosure describes a way to classify MLO relay supportability. According to an embodiment, MLO relay supportability is classified into five MLO relay supportability types. The first MLO relay supportability type may be a MLO relay supportability type where the STA and the AP can communicate with each other directly in a first channel and a second channel and do not communicate with each other using relay operations in the first channel and the second channel (i.e., relay operations are disabled). The second MLO relay supportability type may be a MLO relay supportability type where the STA and the AP can communicate with each other directly in the first channel and the second channel and can also communicate with each other using relay operations in the first channel and the second channel (e.g., relay operations may be used in addition to direction communication to boost throughput). The third MLO relay supportability type may be a MLO relay supportability type where the STA and the AP can communicate with each other directly in the first channel, the AP can communicate directly to the STA in the second channel, and the STA does not communicate to the AP directly in the second channel but can communicate to the AP using relay operations in the second channel (relay operations are used in the uplink direction). The fourth MLO relay supportability type may be a MLO relay supportability type where the STA and the AP can communicate with each other directly in the first channel and do not communicate with each other directly in the second channel but can communicate with each other using relay operations in the second channel. The fifth MLO relay supportability type may be a MLO relay supportability type where the STA and the AP do not communicate with each other directly in the first channel and the second channel but can communicate with each other using relay operations in the first channel and the second channel.

[0044] The present disclosure also describes a way for a STA to provide MLO relay supportability information for the STA to an AP. As used herein, MLO relay supportability information for a STA may be any type of information related to the STA’s MLO relay supportability. For example, MLO relay supportability information for a STA may include an indication of the current MLO relay supportability type for the STA, an identifier of a first link between the STA and the AP in a first channel, an indication of whether uplink transmission is available over the first link, an indication of whether downlink transmission is available over the first link, an identifier of a second link between the STA and the AP in a second channel, an indication of whether uplink transmission is available over the second link, an indication ofwhether downlink transmission is available over the second link, an identifier of a first relay link between the STA and a relay STA in the first channel, and / or an identifier of a second relay link between the STA and a relay STA in the second channel. According to an embodiment, if a STA detects a change in its MLO relay supportability type, the STA may transmit a relay supportability update request message to the AP that includes updated / current MLO relay supportability information for the STA. Responsive to receiving the relay supportability update request message, the AP may store the MLO relay supportability information for the STA and transmit a relay supportability update response message to the STA indicating that the AP has stored the updated MLO relay supportability information for the STA.

[0045] The present disclosure also describes a way for an AP to determine whether the MLO relay supportability type for a STA should be changed. According to an embodiment, the AP transmits a first frame (e.g., a power save polling (PS-Poll) frame) to a relay STA that causes a relay STA to transmit a second frame (e.g., a null data frame). The STA may receive the first frame from the AP and receive the second frame from the relay STA. The STA may then determine a link quality of a first link between the STA and the AP based on the first frame and determine a link quality of a second link between the STA and the relay STA based on the second frame. The STA may then transmit a link quality measurement report message to the AP that includes an indication of the link quality of the first link and an indication of the link quality of the second link. The AP may determine that the MLO relay supportability type for the STA should be changed based on the link quality of the first link and the link quality of the second link indicated in the link quality measurement report message. Responsive to determining that the MLO relay supportability type for the STA should be changed, the AP may configure the STA, the relay STA, and / or the AP to operate in accordance with an updated / current MLO relay supportability type for the STA.

[0046] For purposes of illustration, various embodiments are described herein in the context of wireless networks that are based on IEEE 802.11 standards and using terminology and concepts thereof. Those skilled in the art will appreciate that the embodiments disclosed herein can be modified / adapted for use in other types of wireless networks.

[0047] In the following detailed description, only certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

[0048] Figure 1 shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104). Each of the wireless devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments (e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In one embodiment, the MAC layer of a wireless device 104 may initiate transmission of a frame to another wireless device 104 by passing a PHY- TXSTART. request (TXVECTOR) to the PHY layer. The TXVECTOR provides parameters for generating and / or transmitting a corresponding frame. Similarly, a PHY layer of a receiving wireless device may generate an RXVECTOR, which includes parameters of a received frame and is passed to a MAC layer for processing.

[0049] The plurality of wireless devices 104 may include a wireless device 104A that is an access point (sometimes referred to as an AP station or AP STA) and the other wireless devices 104B1-104B4 that are non-AP stations (sometimes referred to as non-AP STAs). Alternatively, all the plurality of wireless devices 104 may be non-AP STAs in an ad-hoc networking environment. In general, the AP STA (e.g., wireless device 104 A) and the non-AP STAs (e.g., wireless devices 104B1-104B4) may be collectively referred to as STAs. However, for ease of description, only the non-AP STAs may be referred to as STAs unless the context indicates otherwise. Although shown with four non-AP STAs (e.g., the wireless devices 104B1- IO4B4), the WLAN 100 may include any number of non-AP STAs (e.g., one or more wireless devices 104B).

[0050] Figure 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment. The wireless device 104 may be the wireless device 104 A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1. The wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the input interfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.

[0051] The baseband processor 210 performs baseband signal processing and includes a MAC processor 212 and a PHY processor 222. The baseband processor 210 may utilize the memory 232, which may include a non-transitory computer / machine readable medium having software (e.g., computer / machine programing instructions) and data stored therein.

[0052] In an embodiment, the MAC processor 212 includes a MAC software processing unit 214 and a MAC hardware processing unit 216. The MAC software processing unit 214 may implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in the software stored in the storage device 232. The MAC hardware processing unit 216 may implement a second plurality of functions of the MAC layer in specialpurpose hardware. However, the MAC processor 212 is not limited thereto. For example, the MAC processor 212 may be configured to perform the first and second plurality of functions entirely in software or entirely in hardware according to an implementation.

[0053] The PHY processor 222 includes a transmitting (TX) signal processing unit (SPU) 224 and a receiving (RX) SPU 226. The PHY processor 222 implements a plurality of functions of the PHY layer. These functions may be performed in software, hardware, or a combination thereof according to an implementation.

[0054] Functions performed by the transmitting SPU 224 may include one or more of Forward Error Correction (FEC) encoding, stream parsing into one or more spatial streams, diversity encoding of the spatial streams into a plurality of space-time streams, spatial mapping of the space-time streams to transmit chains, inverse Fourier Transform (iFT) computation, Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and the like. Functions performed by the receiving SPU 226 may include inverses of the functions performed by the transmitting SPU 224, such as GI removal, Fourier Transform computation, and the like.

[0055] The RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. The RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) and provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.

[0056] The antenna unit 250 includes one or more antennas. When Multiple-Input Multiple- Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antenna unit 250 may include a plurality of antennas. In an embodiment, the antennas in the antenna unit 250 may operate as a beam-formed antenna array. In an embodiment, the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.

[0057] The input interfaces 234 receive information from a user, and the output interfaces 236 output information to the user. The input interfaces 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, and the like. The output interfaces 236 may include one or more of a display device, touch screen, speaker, and the like.

[0058] As described herein, many functions of the WLAN device 104 may be implemented in either hardware or software. Which functions are implemented in software and which functions are implemented in hardware will vary according to constraints imposed on a design. The constraints may include one or more of design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.

[0059] As described herein, a wide variety of electronic devices, circuits, firmware, software, and combinations thereof may be used to implement the functions of the components of the WLAN device 104. Furthermore, the WLAN device 104 may include other components, such as application processors, storage interfaces, clock generator circuits, power supply circuits, and the like, which have been omitted in the interest of brevity.

[0060] Figure 3 A illustrates components of a WLAN device 104 configured to transmit data according to an embodiment, including a transmitting (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In an embodiment, the TxSP 324, the RF transmitter 342, and the antenna 352 correspond to the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0061] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (TFT) 306, and a guard interval (GI) inserter 308.

[0062] The encoder 300 receives and encodes input data. In an embodiment, the encoder 300 includes a forward error correction (FEC) encoder. The FEC encoder may include a binary convolution code (BCC) encoder followed by a puncturing device. The FEC encoder may include a low-density parity-check (LDPC) encoder.

[0063] The TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 0s or Is. When the encoder 300 performs the BCC encoding, the TxSP 324 may further include an encoder parser for demultiplexing the scrambled bits among a plurality of BCC encoders. If LDPC encoding is used in the encoder, the TxSP 324 may not use the encoder parser.

[0064] The interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein. The interleaver 302 may apply the interleaving only when the encoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.

[0065] The mapper 304 maps the sequence of bits output from the interleaver 302 to constellation points. If the encoder 300 performed LDPC encoding, the mapper 304 may also perform LDPC tone mapping in addition to constellation mapping.

[0066] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may include a plurality of interleavers 302 and a plurality of mappers 304 according to a number of spatial streams (NSS) of the transmission. The TxSP 324 may further include a stream parser for dividing the output of the encoder 300 into blocks and may respectively send the blocks to different interleavers 302 or mappers 304. The TxSP 324 may further include a space-time block code (STBC) encoder for spreading the constellation points from the spatial streams into a number of space-time streams (NSTS) and a spatial mapper for mapping the space-time streams to transmit chains. The spatial mapper may use direct mapping, spatial expansion, or beamforming.

[0067] The IFT 306 converts a block of the constellation points output from the mapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper) to a time domain block (i.e., a symbol) by using an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT). If the STBC encoder and the spatial mapper are used, the IFT 306 may be provided for each transmit chain.

[0068] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming. The TxSP 324 may perform the insertion of the CSD before or after the IFT 306. The CSD may be specified per transmit chain or may be specified per space-time stream. Alternatively, the CSD may be applied as a part of the spatial mapper.

[0069] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0070] The GI inserter 308 prepends a GI to each symbol produced by the IFT 306. Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0071] The RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352. When the TxSP 324 performs a MIMO or MU-MIMO transmission, the GI inserter 308 and the RF transmitter 342 may be provided for each transmit chain.

[0072] Figure 3B illustrates components of a WLAN device 104 configured to receive data according to an embodiment, including a Receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354. In an embodiment, the RxSP 326, RF receiver 344, and antenna 354 may correspond to the receiving SPU 226, the RF receiver 244, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0073] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0074] The RF receiver 344 receives an RF signal via the antenna 354 and converts the RF signal into symbols. The GI remover 318 removes the GI from each of the symbols. When the received transmission is a MIMO or MU-MIMO transmission, the RF receiver 344 and the GI remover 318 may be provided for each receive chain.

[0075] The FT 316 converts each symbol (that is, each time domain block) into a frequency domain block of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). The FT 316 may be provided for each receive chain.

[0076] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBC decoder for despreading the constellation points from the space-time streams into one or more spatial streams.

[0077] The demapper 314 demaps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone demapping before performing the constellation demapping.

[0078] The deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314. The deinterleaver 312 may perform the deinterleaving only when the received transmission was encoded using BCC encoding, and otherwise may output the stream output by the demapper 314 without performing deinterleaving.

[0079] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may use a plurality of demappers 314 and a plurality of deinterleavers 312 corresponding to the number of spatial streams of the transmission. In this case, the RxSP 326 may further include a stream deparser for combining the streams output from the deinterleavers 312.

[0080] The decoder 310 decodes the streams output from the deinterleaver 312 or the stream deparser. In an embodiment, the decoder 310 includes an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

[0081] The RxSP 326 may further include a descrambler for descrambling the decoded data. When the decoder 310 performs BCC decoding, the RxSP 326 may further include an encoder deparser for multiplexing the data decoded by a plurality of BCC decoders. When the decoder 310 performs the LDPC decoding, the RxSP 326 may not use the encoder deparser.

[0082] Before making a transmission, wireless devices such as wireless device 104 will assess the availability of the wireless medium using Clear Channel Assessment (CCA). If the medium is occupied, CCA may determine that it is busy, while if the medium is available, CCA determines that it is idle.

[0083] The PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA (e.g., a wireless device 104) is capable of transmitting and receiving Physical Layer (PHY) Protocol Data Units (PPDUs) (also referred to as PLCP (Physical Layer Convergence Procedure) Protocol Data Units) that are compliant with the mandatory PHY specifications. A PHY specification defines a set of Modulation and Coding Schemes (MCS) and a maximum number of spatial streams. Some PHY entities define downlink (DL) and uplink (UL) Multi-User (MU) transmissions having a maximum number of space-time streams (STS) per user and employing up to a predetermined total number of STSs. A PHY entity may provide support for 10 Megahertz (MHz), 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz contiguous channel widths and support for an 80+80, 80+160 MHz, and 160+160 MHz non-contiguous channel width. Each channel includes a plurality of subcarriers, which may also be referred to as tones. A PHY entity may define signaling fields denoted as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), and the like within a PPDU by which some necessary information about PHY Service Data Unit (PSDU) attributes are communicated. The descriptions below, for sake of completeness and brevity, refer to OFDM-based 802.11 technology. Unless otherwise indicated, a station refers to a non-AP STA.

[0084] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an Access Category (AC) ‘i’ (AIFS[i]). Figure 4 also illustrates a slot time and a data frame is used for transmission of data forwarded to a higher layer. As shown, a WLAN device 104 transmits the data frame after performing backoff if a DIFS has elapsed during which the medium has been idle.

[0085] A management frame may be used for exchanging management information, which is not forwarded to the higher layer. Subtype frames of the management frame include a beacon frame, an association request / response frame, a probe request / response frame, and an authentication request / response frame.

[0086] A control frame may be used for controlling access to the medium. Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame.

[0087] When the control frame is not a response frame of another frame, the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle. When the control frame is the response frame of another frame, the WLAN device 104 transmits the control frame after a SIFS has elapsed without performing backoff or checking whether the medium is idle.

[0088] A WLAN device 104 that supports Quality of Service (QoS) functionality (that is, a QoS STA) may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed. When transmitted by the QoS STA, any of the data frame, the management frame, and the control frame, which is not the response frame, may use the AIFS[AC] of the AC of the transmitted frame.

[0089] A WLAN device 104 may perform a backoff procedure when the WLAN device 104 that is ready to transfer a frame finds the medium busy. The backoff procedure includes determining a random backoff time composed of N backoff slots, where each backoff slot has a duration equal to a slot time and N being an integer number greater than or equal to zero. The backoff time may be determined according to a length of a Contention Window (CW). In an embodiment, the backoff time may be determined according to an AC of the frame. All backoff slots occur following a DIFS or Extended IFS (EIFS) period during which the medium is determined to be idle for the duration of the period.

[0090] When the WLAN device 104 detects no medium activity for the duration of a particular backoff slot, the backoff procedure shall decrement the backoff time by the slot time. When the WLAN device 104 determines that the medium is busy during a backoff slot, the backoff procedure is suspended until the medium is again determined to be idle for the duration of a DIFS or EIFS period. The WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.

[0091] The backoff procedure operates so that when multiple WLAN devices 104 are deferring and execute the backoff procedure, each WLAN device 104 may select a backoff time using a random function and the WLAN device 104 that selects the smallest backoff time may win the contention, reducing the probability of a collision.

[0092] Figure 5 illustrates a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collision between frames in a channel according to an embodiment. Figure 5 shows a first station STA1 transmitting data, a secondstation STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received. The stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.

[0093] The station STA1 may determine whether the channel is busy by carrier sensing. The station STA1 may determine channel occupation / status based on an energy level in the channel or an autocorrelation of signals in the channel, or may determine the channel occupation by using a network allocation vector (NAV) timer.

[0094] After determining that the channel is not used by other devices (that is, that the channel is IDLE) during a DIFS (and performing backoff if required), the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2. Upon receiving the RTS frame, after a SIFS the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame. If Dual-CTS is enabled and the station STA2 is an AP, the AP may send two CTS frames in response to the RTS frame (e.g., a first CTS frame in a non-High Throughput format and a second CTS frame in the HT format).

[0095] When the station STA3 receives the RTS frame, it may set a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using duration information included in the RTS frame. When the station STA3 receives the CTS frame, it may set the NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, the station STA3 may update the NAV timer of the station STA3 by using duration information included in the new frame. The station STA3 does not attempt to access the channel until the NAV timer expires.

[0096] When the station STA1 receives the CTS frame from the station STA2, it may transmit a data frame to the station STA2 after a SIFS period elapses from a time when the CTS frame has been completely received. Upon successfully receiving the data frame, the station STA2 may transmit an ACK frame as a response to the data frame after a SIFS period elapses.

[0097] When the NAV timer expires, the third station STA3 may determine whether the channel is busy using the carrier sensing. Upon determining that the channel is not used by other devices during a DIFS period after the NAV timer has expired, the station STA3 may attempt to access the channel after a contention window elapses according to a backoff process.

[0098] When Dual-CTS is enabled, a station that has obtained a transmission opportunity (TXOP) and that has no data to transmit may transmit a CF-End frame to cut short the TXOP.An AP receiving a CF-End frame having a Basic Service Set Identifier (BSSID) of the AP as a destination address may respond by transmitting two more CF-End frames: a first CF-End frame using Space Time Block Coding (STBC) and a second CF-End frame using non-STBC. A station receiving a CF-End frame resets its NAV timer to 0 at the end of the PPDU containing the CF-End frame. Figure 5 shows the station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.

[0099] The IEEE 802.1 Ibn (Ultra High Reliability, UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi. As shown in Figure 6, the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video-over- WLAN, gaming, AR, and VR. It is noted that various characteristics of UHR (e.g., max PHY rate, PHY rate enhancement, bandwidth / number of spatial streams, and operating bands) are still to be determined.

[0100] The focus of IEEE 802.1 Ibe is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands. In addition to peak PHY rate, different candidate features are under discussion. These candidate features include (1) a 320MHz bandwidth and a more efficient utilization of a non-contiguous spectrum, (2) multi -band / multi-channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.

[0101] The focus of IEEE 802.1 Ibn (UHR) is still under discussion, with candidate features including MLO enhancements (e.g., in terms of increased throughput / reliability and decreased latency), latency and reliability improvements (e.g., multi-AP coordination to support low latency traffic), bandwidth expansion (e.g., to 240, 480, 640 MHz), aggregated PPDU (A- PPDU), enhanced multi-link single-radio (eMLSR) extensions to AP, roaming improvements, and power-saving schemes for prolonging battery life.

[0102] Some features, such as increasing the bandwidth and the number of spatial streams, are solutions that have been proven to be effective in previous projects focused on increasing link throughput and on which feasibility demonstration is achievable.

[0103] With respect to operational bands (e.g., 2.4 / 5 / 6 GHz) for IEEE 802.1 Ibe, more than 1 GHz of additional unlicensed spectrum is likely to be available because the 6 GHzband (5.925- 7.125 GHz) is being considered for unlicensed use. This would allow APs and STAs to become tri-band devices. Larger than 160MHz data transmissions (e.g., 320 MHz or 640 MHz) could be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160MHz data could be transmitted in the 6 GHz band. For example, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0104] In the process of wireless communication, a transmitting station (STA) creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to a receiving STA. The receiving STA then receives, detects, and processes the PPDU.

[0105] The Extremely High Throughput (EHT) PPDU frame encompasses several components. It includes a legacy part, which comprises fields such as the Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), Legacy Signal Field (L-SIG), and Repeated Legacy Signal Field (RL-SIG). These fields are used to maintain compatibility with older Wi-Fi standards.

[0106] In addition to the legacy part, the EHT PPDU frame also contains the Universal Signal Field (U-SIG), EHT Signal Field (EHT-SIG), EHT Short Training Field (EHT-STF), and EHT Long Training Field (EHT-LTF). These fields are specific to the EHT standard and are used for various purposes, such as signaling, synchronization, and channel estimation.

[0107] Figure 7 provides a more detailed description of each field in the EHT PPDU frame, including their purposes and characteristics.

[0108] Regarding the Ultra High Reliability (UHR) PPDU, its frame structure is currently undefined and will be determined through further discussions within the relevant working group or study group. This indicates that the specifics of the UHR PPDU are still under development and will be finalized based on the outcomes of future deliberations.

[0109] The distributed nature of channel access networks, such as IEEE 802.11 WLANs, makes the carrier sense mechanism useful for ensuring collision-free operation. Each station (STA) uses its physical carrier sense to detect transmissions from other STAs. However, in certain situations, it may not be possible for a STA to detect every transmission. For instance, when one STA is located far away from another STA, it might perceive the medium as idle and start transmitting a frame, leading to collisions. To mitigate this hidden node problem, the network allocation vector (NAV) has been introduced.

[0110] As the IEEE 802.11 standard continues to evolve, it now includes scenarios where multiple users can simultaneously transmit or receive data within a basic service set (BSS), such as uplink (UL) and downlink (DL) multi-user (MU) transmissions in a cascaded manner. In these cases, the existing carrier sense and NAV mechanisms may not be sufficient, andmodifications or newly defined mechanisms may be required to facilitate efficient and collision- free operation.

[0111] For the purpose of this disclosure, MU transmission refers to situations where multiple frames are transmitted to or from multiple STAs simultaneously using different resources. Examples of these resources include different frequency resources in Orthogonal Frequency Division Multiple Access (OFDMA) transmission and different spatial streams in Multi-User Multiple Input Multiple Output (MU-MIMO) transmission. Consequently, downlink OFDMA (DL-OFDMA), downlink MU-MIMO (DL-MU-MIMO), uplink OFDMA (UL- OFDMA), uplink MU-MIMO (UL-MU-MIMO), and OFDMA with MU-MIMO are all considered examples of MU transmission.

[0112] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency -Division Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0113] In the IEEE 802.1 lax and 802.1 Ibe specifications, the trigger frame plays a useful role in facilitating uplink multi-user (MU) transmissions. The purpose of the trigger frame is to allocate resources and solicit one or more Trigger-based (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from the associated stations (STAs).

[0114] The trigger frame contains information required by the responding STAs to send their Uplink TB PPDUs. This information includes the Trigger type, which specifies the type of TB PPDU expected, and the Uplink Length (UL Length), which indicates the duration of the uplink transmission.

[0115] Figure 9 illustrates an example scenario where an access point (AP) operating in an 80MHz bandwidth environment sends a Trigger frame to multiple associated STAs. Upon receiving the Trigger frame, the STAs respond by sending their respective Uplink Orthogonal Frequency Division Multiple Access (UL OFDMA) TB PPDUs, utilizing the allocated resources within the specified 80 MHz bandwidth.

[0116] After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame. This acknowledgement can be in the form of an 80MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method. The multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.

[0117] The trigger frame is a useful component in enabling efficient uplink MU transmissions in IEEE 802.1 lax and 802.1 Ibe networks, by allocating resources and coordinating the uplink transmissions from multiple STAs within the same bandwidth.

[0118] Wireless network systems can rely on retransmission of media access control (MAC) protocol data units (MPDUs) when the transmitter (TX) does not receive an acknowledgement from the receiver (RX) or MPDUs are not successfully decoded by the receiver. Using an automatic repeat request (ARQ) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU. With requirements of enhanced reliability and reduced latency, the wireless network system can evolve toward a hybrid ARQ (HARQ) approach.

[0119] There are two methods of HARQ processing. In a first type of HARQ scheme, also referred to as chase combining (CC) HARQ (CC-HARQ) scheme, signals to be retransmitted are the same as the signals that previously failed because all subpackets to be retransmitted use the same puncturing pattern. The puncturing is needed to remove some of the parity bits after encoding using an error-correction code. The reason why the same puncturing pattern is used with CC-HARQ is to generate a coded data sequence with forward error correction (FEC) and to make the receiver use a maximum-ratio combining (MRC) to combine the received, retransmitted bits with the same bits from the previous transmission. For example, information sequences are transmitted in packets with a fixed length. At a receiver, error correction and detection are carried out over the whole packet. However, the ARQ scheme may be inefficient in the presence of burst errors. To solve this more efficiently, subpackets are used. In subpacket transmissions, only those subpackets that include errors need to be retransmitted.

[0120] Since the receiver uses both the current and the previously received subpackets for decoding data, the error probability in decoding decreases as the number of used subpackets increases. The decoding process passes a cyclic redundancy check (CRC) and ends when the entire packet is decoded without error or the maximum number of subpackets is reached. In particular, this scheme operates on a stop-and-wait protocol such that if the receiver can decode the packet, it sends an acknowledgement (ACK) to the transmitter. When the transmitter receives an ACK successfully, it terminates the HARQ transmission of the packet. If the receiver cannot decode the packet, it sends a negative acknowledgement (NAK) to the transmitter and the transmitter performs the retransmission process.

[0121] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmittedsubpacket. IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. The SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket. Self-decoding is possible when the receiving signal- to-noise ratio (SNR) environment is good (i.e., a high SNR). In some embodiments, subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0122] AP coordination has been considered as a potential technology to improve WLAN system throughput in the IEEE 802.1 Ibe standard and is still being discussed in the IEEE 802.11bn (UHR) standard. To support various AP coordination schemes, such as coordinated beamforming, OFDMA, TDMA, spatial reuse, and joint transmission, a predefined mechanism for APs is necessary.

[0123] In the context of coordinated TDMA (C-TDMA), the AP that obtains a transmit opportunity (TXOP) is referred to as the sharing AP. This AP initiates the AP coordination schemes to determine the AP candidate set by sending a frame, such as a Beacon frame or probe response frame, which includes information about the AP coordination scheme capabilities. The AP that participates in the AP coordination schemes after receiving the frame from the sharing AP is called the shared AP. The sharing AP is also known as the master AP or coordinating AP, while the shared AP is referred to as the slave AP or coordinated AP.

[0124] The operation of various AP coordination schemes has been discussed in the IEEE 802.1 Ibe and UHR standards:

[0125] Coordinated Beamforming (C-BF): Multiple APs transmit on the same frequency resource by coordinating and forming spatial nulls, allowing for simultaneous transmission from multiple APs.

[0126] Coordinated OFDMA (C-OFDMA): APs transmit on orthogonal frequency resources by coordinating and splitting the spectrum, enabling more efficient spectrum utilization.

[0127] Joint Transmission (JTX): Multiple APs transmit jointly to a given user simultaneously by sharing data between the APs.

[0128] Coordinated Spatial Reuse (C-SR): Multiple APs or STAs adjust their transmit power to reduce interference between APs.

[0129] By implementing these AP coordination schemes, WLAN systems can improve their overall throughput and efficiency by leveraging the cooperation between multiple APs.

[0130] Figure 10 is a diagram showing a wireless network environment with an AP, relay STAs, and STAs that are capable of MLO in a 2.4 GHz band and a 5 GHz band, according to some embodiments.

[0131] As shown in the diagram, the wireless network environment may include an AP 1010, two relay STAs (relay STA 1020-1 and relay STA 1020-2), and five non-AP non-relay STAs (STA 1030-1, STA 1030-2, STA 1030-3, STA 1030-4, and STA 1030-5). The AP 1010, relay STAs, and STAs may be multi -link devices (MLDs) that are capable of MLO. Unlike traditional non-MLD APs and non-MLD STAs, MLD APs and STAs may have multiple wireless interfaces and may be capable of MLO in multiple channels / bands. In this example, it is assumed that the AP 1010, relay STAs, and non-relay STAs may be capable of MLO in a first channel in the 2.4 GHz band and a second channel in the 5 GHz band. It is noted that MLDs having multiple wireless interfaces may still have a unique MAC instance at the upper layers, without losing the independent parameters of each wireless interface.

[0132] The AP 1010 may operate a basic service set (BSS) in the 2.4 GHz band and the 5 GHz band (using two wireless interfaces). In the example shown in the diagram, the AP’s 1010 coverage in the 2.4 GHz band may extend further than the AP’s 1010 coverage in the 5 GHz band (due to the 2.4 GHz band being a lower frequency band).

[0133] Various embodiments will be described herein in the context of the wireless network environment shown in Figure 10. It should be appreciated, however, that the techniques described herein may be applicable to other wireless network environments having different configurations.

[0134] Figure 11 is a diagram showing a single link operation and a multi-link operation between an AP and a non-AP STA, according to some embodiments.

[0135] As shown in the diagram, with a single link operation, an AP 1110 and a non-AP STA 1130 may communicate with each other over a single link. In contrast, with a multi-link operation, an AP MLD 1150 and a non-AP STA MLD 1170 may communicate with each other over multiple links. For example, as shown in the diagram, the AP MLD 1150 may have a first instance (“API”) and a second instance (“AP2”). Similarly, the non-AP STA MLD 1170 may also have a first instance (“STA1”) and a second instance (“STA2”). The AP MLD 1150 may communicate with the non-AP STA MLD 1170 over a first link (“Linkl”) between API and STA1 and a second link (“Link2”) between AP2 and STA2.

[0136] A relay STA (rSTA) may be a non-AP STA that can relay communications between an AP and a non-AP STA. Relay operations may extend the possible communication range and provide improved QoS (e.g., reliability and throughput) in a wireless network. For example, relay STA 1020-1 shown in Figure 10 may relay communications between the AP 1010 and STA 1030-2 and / or STA 1030-5. Also, relay STA 1020-2 shown in Figure 10 may relay communications between AP 1010 and STA 1030-3 and / or STA 1030-4.

[0137] Figure 12 is a diagram showing a relay STA MLD that can relay communications between an AP MLD and a non-AP STA MLD using MLO, according to some embodiments.

[0138] When MLO is supported in a wireless network, the relay operations can also use MLO. For example, as shown in the diagram, an AP MLD 1210 may have a first instance (“API”) and a second instance (“AP2”), a relay STA MLD 1220 may have a first instance (“rSTAl”) and a second instance (“rSTA2”), and the non-AP STA MLD 1230 may have a first instance (“STA1”) and a second instance (“STA2”). API and rSTAl may communicate with each other over a link (“Linkl-1”) that operates in a first channel (e.g., a channel in the 2.4 GHz band). rSTAl and STA1 may communicate with each other over a link (“Linkl-2”) that operates in the first channel. AP2 and rSTA2 may communicate with each other over a link (“Link2-1”) that operates in a second channel (e.g., a channel in the 5 GHz band) that is different from the first channel. rSTA2 and STA2 may communicate with each other over a link (“Link2-2”) that operates in the second channel. API and STA1 may communicate with each other in the first channel via rSTAl. For example, downlink traffic going from API to STA1 may be transmitted in the first channel over Linkl-1 and Linkl-2 (in that order) and uplink traffic going from STA1 to API may be transmitted in the first channel over Linkl-2 and Linkl- 1 (in that order). Similarly, AP2 and STA2 may communicate with each other in the second channel via rSTA2. For example, downlink traffic going from AP2 to STA2 may be transmitted in the second channel over Link2-1 and Link2-2 (in that order) and uplink traffic going from STA2 to AP2 may be transmitted in the second channel over Link2-2 and Link2-1 (in that order). In this way, the AP MLD 1210 may be able to communicate with the non-AP STA MLD 1230 via the relay STA MLD 1220 (using relay operations) in two different channels over two different sets of links.

[0139] Figure 13 is a diagram showing a table of MLO relay supportability types, according to some embodiments.

[0140] As shown in the table, MLO relay supportability may be classified into five MLO relay supportability types: MLO relay supportability type #0, MLO relay supportability type #1, MLO relay supportability type #2, MLO relay supportability type #3, and MLO relaysupportability type #4. The MLO relay supportability type for a STA may depend on the link status of the links between the STA and an AP. In an embodiment, three bits are used to indicate the MLO relay supportability type. For example, MLO relay supportability type #0 may correspond to binary “000,” MLO relay supportability type #1 may correspond to binary “001,” MLO relay supportability type #2 may correspond to binary “010,” MLO relay supportability type #3 may correspond to binary “011,” and MLO relay supportability type #4 may correspond to binary “100 ”

[0141] As shown in the table, with MLO relay supportability type #0, the non-AP STA and the AP are within one-hop communication range and relay operations are disabled. The non-AP STA and the AP may communicate with each other directly and relay operations may be disabled. For example, in the wireless network environment shown in Figure 10, STA 1030-1 and AP 1010 may communicate with each other directly (without using relay operations). As used herein, “direct” communication or similar language refers to communication that does not involve relay operations.

[0142] With MLO relay supportability type #1, the non-AP STA and the AP are within one- hop communication range and a relay STA can relay traffic between the non-AP STA and the AP (e.g., to boost end-to-end throughput). The non-AP STA and the AP may communicate with each other directly and / or communicate with each other using relay operations. For example, in the wireless network environment shown in Figure 10, STA 1030-2 and AP 1010 may communicate with each other directly (without using relay operations) and also communicate with each other via relay STA 1020-1 (using relay operations).

[0143] With MLO relay supportability type #2, the non-AP STA is able to receive beacon and downlink traffic from the AP (so the non-AP STA is shown as being “connected” to the AP) but the non-AP STA is not able to deliver uplink traffic to the AP due to a downlink / uplink power asymmetry (e.g., because the AP has higher transmit power than the non-AP STA) or other reason. A relay STA may be able to relay uplink traffic from the non-AP STA to the AP to address the asymmetry. For example, in the wireless network environment shown in Figure 10, AP 1010 may communicate to STA 1030-3 directly (in the downlink direction) and STA 1030-3 may communicate to AP 1010 (in the uplink direction) via relay STA 1020-2 (using relay operations).

[0144] With MLO relay supportability type #3, the non-AP STA and the AP are within one- hop communication range in one band (e.g., 2.4 GHz band) but are not within one-hop communication range in another band (e.g., 5 GHz band). The non-AP STA and the AP may communicate with each other directly in one band (e.g., 2.4 GHz band) and communicate witheach other in the other band (e.g., 5 GHz band) using relay operations. For example, in the wireless network environment shown in Figure 10, AP 1010 and STA 1030-4 may communicate with each other directly (without using relay operations) in the 2.4 GHz band and communicate with each other via relay STA 1020-2 in the 5 GHz band.

[0145] With MLO relay supportability type #4, the non-AP STA and the AP are not within one-hop communication range but a relay STA can relay traffic between the non-AP STA and the AP to extend coverage and enable communication. The non-AP STA and the AP may not be able to communicate with each other directly but may be able to communicate with each other using relay operations. For example, in the wireless network environment shown in Figure 10, STA 1030-5 and AP 1010 may communicate with each other via relay STA 1020-1 in both the 2.4 GHz band and the 5 GHz band.

[0146] Figure 14 is a diagram showing a table summarizing the types of communications available for each MLO relay supportability type, according to some embodiments.

[0147] As shown in the table, for MLO relay supportability type #0 (“000”), direct downlink communication is available, relayed downlink communication is unavailable, direct uplink communication is available, and relayed uplink communication is unavailable. For MLO relay supportability type #1 (“001”), direct downlink communication is available, relayed downlink communication is available, direct uplink communication is available, and relayed uplink communication is available. For MLO relay supportability type #2 (“010”), direct downlink communication is available, relayed downlink communication is available, direct uplink communication is unavailable (at least in one channel / band), and relayed uplink communication is available. For MLO relay supportability type #3 (“011”), direct downlink communication is available in one channel / band but not available in another channel / band, relayed downlink communication is available, direct uplink communication is available in one channel / band but not available in another channel / band, and relayed uplink communication is available. For MLO relay supportability type #4 (“100”), direct downlink communication is unavailable, relayed downlink communication is available, direct uplink communication is unavailable, and relayed uplink communication is available.

[0148] The various MLO relay supportability types will now be described in additional detail herein.

[0149] Figure 15 is a diagram showing MLO relay supportability type #1 (“001”), according to some embodiments.

[0150] As shown in the diagram, an AP 1510, a relay STA 1520, and a non-AP STA 1530 may be MLDs that each have two instances. For example, the AP 1510 may have instances“API” and “AP2,” the relay STA 1520 may have instances “rSTAl” and “rSTA2,” and the non- AP STA 1530 may have instances “STA1” and “STA2.” API and STA1 may communicate with each other directly in a first channel over link “Linkl.” Also, API and STA1 may communicate with each other in the first channel via rSTAl over link “Linkl-1” and link “Linkl -2.” AP2 and STA2 may communicate with each other directly in a second channel over link “Link2.” Also, AP2 and STA2 may communicate with each other in the second channel via rSTA2 over link “Link2-1” and link “Link2-2.”

[0151] Thus, the non-AP STA 1530 has the option to communicate directly with the AP 1510 (over Linkl and / or Link2) and / or communicate with the AP 1510 via the relay STA 1520 (over Linkl-1 and Linkl -2 or over Link2-1 and Link2-2). The decision of whether to communicate directly or communicate via the relay STA 1520 may be made depending on the channel conditions. For example, if the link quality of the direct links (e.g., Linkl and Link2) is sufficiently high, then the use of direct communications may be prioritized. However, if the link quality of the relay links (e.g., Linkl-1, Linkl-2, Link2-1, and Link2-2) is higher than the link quality of the direct links (e.g., the channel gain achieved through the use of relay links is above a predefined threshold), then the use of relayed communication may be prioritized. Link quality may be measured using various metrics such as bit error rate (BER), signal -to-noise ratio (SNR), or the like. When the link quality of the direct links is low, the use of relay operations over the relay links may provide enhanced link quality and channel conditions, enabling the use of higher order modulation coding scheme (MCS) for transmission, which may result in improved performance. This improvement in performance may be attributed to the benefits derived from Multiple-Input Multiple-Output (MIMO) antenna gain and increased number of MIMO streams.

[0152] Figure 16 is a diagram showing MLO relay supportability type #2 (“010”), according to some embodiments.

[0153] As shown in the diagram, an AP 1610, a relay STA 1620, and a non-AP STA 1630 may be MLDs that each have two instances. For example, the AP 1610 may have instances “API” and “AP2,” the relay STA 1620 may have instances “rSTAl” and “rSTA2,” and the non- AP STA 1630 may have instances “STA1” and “STA2.” API and STA1 may communicate with each other directly in a first channel over link “Linkl.” Also, API and STA1 may communicate with each other in the first channel via rSTAl over link “Linkl-1” and link “Linkl-2.” AP2 may communicate to STA2 directly in a second channel (e.g., AP2 may deliver beacon and downlink traffic to STA2) but STA2 may not be able to communicate to AP2 directly in the second channel. Stated differently, the communications between AP2 and STA2 in the second channel may be asymmetric (e.g., due to a downlink / uplink power asymmetry).However, AP2 and STA2 may communicate with each other in the second channel via rSTA2 over link “Link2-1” and link “Link2-2” to address the asymmetry, allowing bidirectional communication between the AP 1610 and the non-AP STA 1630 in the second channel.

[0154] Figure 17 is a diagram showing MLO relay supportability type #3 (“Oi l”), according to some embodiments.

[0155] As shown in the diagram, an AP 1710, a relay STA 1720, and a non-AP STA 1730 may be MLDs that each have two instances. For example, the AP 1710 may have instances “API” and “AP2,” the relay STA 1720 may have instances “rSTAl” and “rSTA2,” and the non- AP STA 1730 may have instances “STA1” and “STA2.” API and STA1 may communicate with each other directly in a first channel over link “Linkl.” Also, API and STA1 may communicate with each other in the first channel via rSTAl over link “Linkl-1” and link “Linkl -2.” AP2 and STA2 may not be able to communicate with each other directly in a second channel (link “Link2” is unavailable). However, AP2 and STA2 may be able to communicate with each other in the second channel via rSTA2 over link “Link2-1” and link “Link2-2.” Stated differently, the AP 1710 and the non-AP STA 1730 may be able to communicate with each other directly in the first channel (over Linkl) but may not be able to communicate with each other directly in the second channel. However, the AP 1710 and the non-AP STA 1730 may be able to communicate with each other in the second channel via relay STA 1720. Thus, relay operations can be used to extend the coverage in the second channel to allow the AP 1710 and the non-AP STA 1730 to communicate with each other.

[0156] Figure 18 is a diagram showing MLO relay supportability type #4 (“100”), according to some embodiments.

[0157] As shown in the diagram, an AP 1810, a relay STA 1820, and a non-AP STA 1830 may be MLDs that each have two instances. For example, the AP 1810 may have instances “API” and “AP2,” the relay STA 1820 may have instances “rSTAl” and “rSTA2,” and the non- AP STA 1830 may have instances “STA1” and “STA2.” API and STA1 may not be able to communicate with each other directly in a first channel (link “Linkl” is unavailable). However, API and STA1 may be able to communicate with each other in the first channel via rSTAl over link “Linkl-1” and link “Linkl-2.” Also, AP2 and STA2 may not be able to communicate with each other directly in a second channel (link “Link2” is unavailable). However, AP2 and STA2 may be able to communicate with each other in the second channel via rSTA2 over link “Link2- 1” and link “Link2-2.” Stated differently, the AP 1810 and the non-AP STA 1830 may not be able to communicate with each other directly in the first channel (over Linkl) or the second channel (over Link2) but may be able to communicate with each other in the first channel andthe second channel via the relay STA 1820. Thus, relay operations can be used to extend the coverage in the first channel and the second channel to allow the AP 1810 and the non-AP STA 1830 to communicate with each other.

[0158] A MLO relay supportability type may support any communications that can be supported by the links that are available for that MLO relay supportability type. For example, MLO relay supportability type #1 may support the relay operations supported by MLO relay supportability types #2, #3, and #4. Similarly, MLO relay supportability type #2 may support the relay operations supported by MLO relay supportability types #3 and #4. Similarly, MLO relay supportability type #3 may support the relay operations supported by MLO relay supportability type #4. The MLO relay supportability types #l-#4 may thus be considered as having a subset relationship in terms of the communications that can be supported (with MLO relay supportability type #1 supporting the most types of communications and MLO relay supportability type #4 supporting the least types of communications).

[0159] Figure 19 is a diagram showing a non-AP STA MLD that includes a MLD link status monitoring component, according to some embodiments.

[0160] As shown in the diagram, a non-AP STA MLD 1920 may include a MLD link status monitoring component 1925, a first STA instance (“STA1”) and a second STA instance (“STA2”). The MLD link status monitoring component 1925 may (proactively or reactively) monitor the link status of multiple links connected to the non-AP STA MLD 1920 and detect when the link status of a link has changed. For example, the MLD link status monitoring component 1925 may monitor the links connected to STA1 and the links connected to STA2 and detect when the link status of any of those links have changed (e.g., from being available to unavailable or vice versa). The MLD link status monitoring component 1925 may determine the link status of a link using the received signal strength of transmissions received over the link or other suitable means. As will be described in additional detail herein, the non-AP STA MLD 1920 may determine the MLO relay supportability type for the non-AP STA MLD 1920 based on the link status of the links.

[0161] Figure 20 is a flow diagram showing a method for determining a MLO relay supportability type, according to some embodiments. The method may be performed by a non- AP STA.

[0162] As shown in the diagram, at operation 2005, the non-AP STA may determine the status of its MLD links. In this example, it is assumed that the MLD links include a low frequency link (e.g., that operates in the 2.4 GHz band) and a high frequency link (e.g., that operates in the 5 GHz band). At operation 2015, the non-AP STA may determine whether theuse of relay operations is allowed. If the use of relay operations is not allowed, then the non-AP STA may determine that the MLO relay supportability type is “000” (MLO relay supportability type #0). Otherwise, if the use of relay operations is allowed, then the flow may move to operation 2010. At operation 2010, the non-AP STA may determine whether all links are available. If all links are available, then the non-AP STA may determine that the MLO relay supportability type is “001” (MLO relay supportability type #1). Otherwise, if a link is unavailable, the flow may move to operation 2020. At operation 2020, the non-AP STA may determine whether uplink and downlink transmissions are available over the low frequency link (e.g., the link operating in the 2.4 GHz band). If uplink and downlink transmissions are unavailable over the low frequency link, the non-AP STA may determine that the MLO relay supportability type is “100” (MLO relay supportability type #4). Otherwise, if uplink and downlink transmissions are available over the low frequency link, then the flow may move to operation 2025. At operation 2025, the non-AP STA may determine whether downlink transmission is available over the high frequency link (e.g., the link operating in the 5 GHz band). If downlink transmission is unavailable over the high frequency link, then the non-AP STA may determine that the MLO relay supportability type is “011” (MLO relay supportability type #3). Otherwise, if downlink transmission is available over the high frequency link, then the non-AP STA may determine that the MLO relay supportability type is “010” (MLO relay supportability type #2).

[0163] Figure 21 is a diagram showing a frame exchange sequence for a non-AP STA to provide MLO relay supportability information to an AP via a relay STA, according to some embodiments.

[0164] As shown in the diagram, at operation 2105, a non-AP STA may monitor the link status of its links (e.g., the links between the non-AP STA and a rSTA and / or links between the non-AP STA and an AP). At operation 2110, the non-AP STA may determine that the MLO relay supportability type for the STA has changed (e.g., based on a change in link status). Responsive to detecting the change, the non-AP STA may transmit a relay supportability update request message 2115 to the AP via the relay STA (“rSTA”). The relay supportability update request message 2115 may include updated MLO relay supportability information for the STA, which may include information regarding an indication of the current MLO relay supportability type for the non-AP STA, an identifier of a first link between the STA and the AP in a first channel, an indication of whether uplink transmission is available over the first link, an indication of whether downlink transmission is available over the first link, an identifier of a second link between the non-AP STA and the AP in a second channel, an indication of whetheruplink transmission is available over the second link, an indication of whether downlink transmission is available over the second link, an identifier of a first relay link between the STA and the relay STA in the first channel, and / or an identifier of a second relay link between the STA and the relay STA in the second channel. At operation 2120, upon receiving the relay supportability update request message, the AP may store the MLO relay supportability information for the STA (e.g., in its WLAN client association list) and configure itself, the relay STA, and / or the STA to operate in accordance with the new MLO relay supportability type for the STA. The AP may then transmit a relay supportability update response message 2125 to the non-AP STA via the relay STA. The relay supportability update response message 2125 may include an indication of whether the update / configuration was successful or not. If the update / configuration encounters inconsistencies or other type of error, the relay supportability update response message 2125 may indicate as such.

[0165] Figure 22 is a diagram showing a frame exchange sequence for an AP to determine link quality and determine whether the MLO relay supportability type for a STA should be changed, according to some embodiments.

[0166] As shown in the diagram, an AP may transmit a PS-Poll frame 2210 to the non-AP STA via the relay STA. Responsive to receiving the PS-Poll frame 2210, the relay STA may transmit a null data frame 2215 to the non-AP STA and the AP. While the diagram shows the relay STA transmitting a single null data frame 2215 to the non-AP STA and the AP, the relay STA may transmit separate null data frames to the non-AP STA and the AP in some embodiments. At operation 2225, responsive to receiving the PS-Poll frame 2210 and the null data frame 2215, the non-AP STA may determine the link quality of the link between the non- AP STA and the AP based on the PS-Poll frame 2210 and may determine the link quality of the link between the non-AP STA and the relay STA based on the null data frame 2215. The non- AP STA may determine the link quality of a link using channel state information (CSI), received signal strength indication (RSSI), signal-to-noise ratio (SNR), and / or channel quality indicator (CQI). It should be appreciated, however, that other metrics can be used. The non-AP STA may then transmit a link quality measurement report message 2235 to the AP via the relay STA. The link quality measurement report message 2235 may include an indication of the link quality of the link between the non-AP STA and the relay STA and an indication of the link quality of the link between the non-AP STA and the AP. In an embodiment, the non-AP STA transmits a null data frame 2220 to the AP to allow the AP to determine the uplink link quality. At operation 2230, the AP may determine the uplink link quality of the link between the relay STA and the AP based on the null data frame 2215 and may determine the uplink link quality of thelink between the non-AP STA and the AP based on the null data frame 2220 (if applicable). The operations described above may be repeated for each channel (e.g., in a first channel in the 2.4 GHz band and a second channel in the 5 GHz band) to allow the AP to determine the link quality in each channel. At operation 2240, the AP may determine whether the MLO relay supportability type for the non-AP STA should be changed based on the link qualities / statuses of the links. The AP may periodically transmit a PS-Poll frame 2210 to the non-AP STA and relay STA to periodically assess the link quality and determine whether the MLO relay supportability type for the non-AP STA should be changed.

[0167] Figure 23 is a diagram showing a frame exchange sequence for a non-AP STA to provide MLO relay supportability information to an AP directly, according to some embodiments.

[0168] If a non-AP STA has a direct connection to an AP, the non-AP STA may provide MLO relay supportability information to the AP directly (without using relay operations). For example, as shown in the diagram, at operation 2305, the non-AP STA may monitor the link status of its links (e.g., the links between the non-AP STA and a rSTA and / or the links between the non-AP STA and the AP). At operation 2310, the non-AP STA may determine that the MLO relay supportability type for the STA has changed (e.g., based on a change in link status). Responsive to detecting the change, the non-AP STA may transmit a relay supportability update request message 2315 to the AP directly (without using relay operations). The relay supportability update request message 2315 may include MLO relay supportability information for the STA, similar to the relay supportability update request message 2115 described above. At operation 2320, upon receiving the relay supportability update request message, the AP may store the MLO relay supportability information for the STA (e.g., in its WLAN client association list) and configure itself, the relay STA, and / or the STA to operate in accordance with the new MLO relay supportability type for the STA. The AP may then transmit a relay supportability update response message 2325 to the non-AP STA (without using relay operations). The relay supportability update response message 2325 may include an indication of whether the update / configuration was successful or not. If the update / configuration encounters inconsistencies or other type of error, the relay supportability update response message 2325 may indicate as such.

[0169] Figure 24 is a diagram showing a relay supportability information element, according to some embodiments.

[0170] A relay supportability information element may be used for carrying MLO relay supportability information. The relay supportability information element may be included in arelay supportability update request message to carry relay supportability information for a STA. As shown in the diagram, the relay supportability information element may include a relay supportability type field 2405, a first direct link (“D-Linkl”) identifier field 2410, a first uplink and downlink (UL / DL) availability field 2415, a second direct link (“D-Link2”) identifier field 2420, a second uplink and downlink (UL / DL) availability field 2425, a first relay link (“R- Linkl”) identifier field 2430, and a second relay link (“R-Link2”) identifier field 2435. While a certain format of a relay supportability information element is shown in the diagram and described herein, it should be appreciated that the relay supportability information element can have a different format than what is shown and described herein (e.g., it may include additional fields, fewer fields, a different order of fields, etc.).

[0171] The relay supportability type field 2405 may be used for carrying an indication of the current MLO relay supportability type for the STA. In an embodiment, the relay supportability type field 2405 has a length of three bits (e.g., to be able to indicate the five different MLO relay supportability types described herein). The first direct link identifier field 2410 may be used for carrying an identifier of a first link between the STA and the AP that operates in a first channel (e.g., in the 2.4 GHz band). The first uplink and downlink availability field 2415 may be used for carrying an indication of whether uplink transmission is available over the first link and an indication of whether downlink transmission is available over the first link. The second direct link identifier field 2420 may be used for carrying an identifier of a second link between the STA and the AP that operates in a second channel (e.g., in the 5 GHz band). The second uplink and downlink availability field 2425 may be used for carrying an indication of whether uplink transmission is available over the second link and an indication of whether downlink transmission is available over the second link. The first relay link identifier field 2430 may be used for carrying an identifier of a first relay link between the STA and the relay STA that operates in the first channel. The second relay link identifier field 2435 may be used for carrying an identifier of a second relay link between the STA and the relay STA that operates in the second channel.

[0172] In an embodiment, the first uplink and downlink availability field 2415 and the second uplink and downlink availability field 2425 each include two bits (referred to herein as B0 and Bl), where B0 is used for indicating uplink transmission availability and Bl is used for indicating downlink transmission availability. A bit may be set to binary “1” if the corresponding transmission direction is available over the corresponding link and set to binary “0” otherwise (but the opposite convention could be used in some embodiments).

[0173] In an embodiment, when the MLO relay supportability type is “000,” the first relay link identifier field 2430 and the second relay link identifier field 2435 are not used (e.g., they are empty, filled with a default value, or ignored).

[0174] In an embodiment, when the MLO relay supportability type is “001,” the first direct link identifier field 2410 and the second direct link identifier field 2420 may carry the identifiers of the respective direct links. Also, the first uplink / downlink availability field 2415 may carry an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link (e.g., carry a value of binary “11” (i.e., B0=l and B 1=1)) and the second uplink / downlink availability field 2425 may carry an indication that uplink transmission is available over the second link and an indication that downlink transmission is available over the second link (e.g., carry a value of binary “11” (i.e., B0=l and B 1=1)). Also, the first relay link identifier field 2430 and the second relay link identifier field 2435 may carry an identifier of a first relay link between the STA and the relay STA that operates in the first channel and an identifier of a second relay link between the STA and the relay STA that operates in the second channel, respectively.

[0175] In an embodiment, when the MLO relay supportability type is “010,” the first direct link identifier field 2410 may carry an indication of a first (direct) link over which both uplink transmission and downlink transmission are available. The first uplink and downlink availability field 2415 may carry an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link (e.g., carry a value of binary “11” (i.e., B0=l and Bl=l)). Also, the second direct link identifier field 2420 may carry an indication of a second (direct)link over which only downlink transmission is available (the link over which communication is asymmetric). The second uplink and downlink availability field 2425 may carry an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is available over the second link (e.g., carry a value of binary “01” (i.e., B0=0 and Bl=l)).

[0176] In an embodiment, when the MLO relay supportability type is “011,” the first direct link identifier field 2410 may carry an indication of a first (direct) link over which both uplink transmission and downlink transmission are available. The first uplink and downlink availability field 2415 may carry an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link (e.g., carry a value of binary “11” (i.e., B0=l and Bl=l)). The second direct link identifier field 2420 may carry an indication of a second (direct) link over which uplink transmission and downlink transmission are unavailable. The second uplink and downlink availability field 2425 may carryan indication that uplink transmission is unavailable over the link and an indication that downlink transmission is unavailable over the link (e.g., carry a value of binary “00” (i.e., B0=0 and Bl=0)).

[0177] In an embodiment, when the MLO relay supportability type is “100,” the first direct link identifier field 2410 may carry an indication of a first (direct)link over which both uplink transmission and downlink transmission are unavailable and the second direct link identifier field 2420 may carry an indication of a second (direct)link over which both uplink transmission and downlink transmission are unavailable. The first uplink and downlink availability field 2415 may carry an indication that uplink transmission is unavailable over the first link and an indication that downlink transmission is unavailable over the first link (e.g., carry a value of binary “00” (i.e., B0=0 and B 1=0)). Also, the second uplink and downlink availability field 2425 may carry an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is unavailable over the second link (e.g., carry a value of binary “00” (i.e., B0=0 and B 1=0)). Also, the first relay link identifier field 2430 and the second relay link identifier field 2435 may carry an identifier of a first relay link between the STA and the relay STA that operates in the first channel and an identifier of a second relay link between the STA and the relay STA that operates in the second channel.

[0178] It is noted that the relay STA may also be considered to be a non-AP STA (i.e., a leaf STA), which means that it can also communicate with the AP via another relay STA.

[0179] Figure 25 is a diagram showing changes in the MLO relay supportability type for a STA, according to some embodiments.

[0180] As shown in the diagram, the MLO relay supportability type for a STA MLD may initially be “001” (MLO relay supportability type #1). In this state, the STA MLD may communicate with an AP MLD directly over a first link (“Linkl”) and a second link (“Link2”). Also, the STA MLD may communicate with the AP MLD via a relay STA (“rSTA”) MLD over a first relay link (“rLinkl”) and a second relay link (“rLink2”). In the diagram, the links in dashed lines represent links that operate in a lower frequency channel (e.g., in the 2.4 GHz band) and the links in solid lines represent links that operate in a higher frequency channel (e.g., in the 5 GHz band).

[0181] As shown in the diagram, the MLO relay supportability type for the STA MLD may change from “001” to “010” (MLO relay supportability type #2). In the updated state, the STA MLD may communicate with an AP MLD directly over a first link (“Linkl”). Also, the AP MLD may be able to communicate to the STA MLD directly over a second link (“Link2”) but the STA MLD may not be able to communicate to the AP MLD directly over Link2 (i.e., onlydownlink transmission is available over Link2). Also, the STA MLD may communicate with the AP MLD via a relay STA (“rSTA”) MLD over a first relay link (“rLinkl”) and a second relay link (“rLink2”).

[0182] As shown in the diagram, the MLO relay supportability type for the STA MLD may change from “010” to “100” (MLO relay supportability type #4). In the updated state, the STA MLD may not be able to communicate with an AP MLD directly (e.g., as represented in the diagram by the absence of direct links between the STA MLD and the AP MLD). However, the STA MLD may communicate with the AP MLD via a relay STA (“rSTA”) MLD over a first relay link (“rLinkl”) and a second relay link (“rLink2”).

[0183] Embodiments have been described that consider the use of relay operations with MLO-capable devices. In particular, embodiments provide a way to classify MLO relay supportability and to provide MLO relay supportability information. Also, embodiments provide a way to determine the link quality / state of MLD links to determine when the MLO relay supportability type for a STA should be changed. Embodiments may be used to support the combined usage of MLO and relay operations in a wireless network, which can help improve communication range / coverage, throughput, and / or reliability.

[0184] While embodiments have been described herein where there are two MLD links (e.g., one link operating in the 2.4 GHz band and one link operating in the 5 GHz band), it should be appreciated that the techniques described herein may also be applied to scenarios with more than two MLD links.

[0185] Turning now to Figure 26, a method 2600 will be described for providing MLO relay supportability information, in accordance with an example embodiment. The method 2600 may be performed by a STA to provide MLO relay supportability information to an AP. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0186] Additionally, although shown in a particular order, in some embodiments the operations of the method 2600 (and the other methods shown in the other figures) may be performed in a different order. For example, although the operations of the method 2600 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0187] At operation 2605, the STA monitors the link status of its links.

[0188] At operation 2610, the STA determines whether it has detected a change in MLO relay supportability type for the STA (e.g., based on a change in the link status of its links). If the STA has not detected a change in MLO relay supportability type, the flow moves to operation 2605, where the STA continues to monitor the link status of its links. Otherwise, ifthe STA has detected a change in MLO relay supportability type, the flow moves to operation 2615.

[0189] The change in MLO relay supportability type may be from a previous MLO relay supportability type to a current MLO relay supportability type. In an embodiment, the current MLO relay supportability type for the STA is any one of: a first MLO relay supportability type, a second MLO relay supportability type, a third MLO relay supportability type, a fourth MLO relay supportability type, and a fifth MLO relay supportability type. The first MLO relay supportability type (e.g., MLO relay supportability type #0 (“000”)) may be a relay supportability type where the STA and the AP can communicate with each other directly in a first channel and a second channel and do not communicate with each other using relay operations in the first channel and the second channel. The second MLO relay supportability type (e.g., MLO relay supportability type #1 (“001”)) may be a relay supportability type where the STA and the AP can communicate with each other directly in the first channel and the second channel and can also communicate with each other using relay operations in the first channel and the second channel. The third MLO relay supportability type (e.g., MLO relay supportability type #2 (“010”)) may be a relay supportability type where the STA and the AP can communicate with each other directly in the first channel, the AP can communicate directly to the STA in the second channel, and the STA does not communicate to the AP directly in the second channel but can communicate to the AP using relay operations in the second channel. The fourth MLO relay supportability type (e.g., MLO relay supportability type #3 (“011”)) may be a relay supportability type where the STA and the AP can communicate with each other directly in the first channel and do not communicate with each other directly in the second channel but can communicate with each other using relay operations in the second channel. The fifth MLO relay supportability type (e.g., MLO relay supportability type #4 (“100”)) may be a relay supportability type where the STA and the AP do not communicate with each other directly in the first channel and the second channel but can communicate with each other using relay operations in the first channel and the second channel. In an embodiment, first channel is in a 2.4 GHz band and the second channel is in a 5 GHz band.

[0190] At operation 2615, the STA transmits a relay supportability update request message to the AP that includes updated MLO relay supportability information for the STA. In an embodiment, the relay supportability update request message includes a relay supportability type field that carries an indication of the current MLO relay supportability type for the STA. In an embodiment, the relay supportability update request message further includes a first direct link identifier field for carrying an identifier of a first link between the STA and the AP that operatesin the first channel, a first uplink / downlink availability field for carrying an indication of whether uplink transmission is available over the first link and an indication of whether downlink transmission is available over the first link, a second direct link identifier field for carrying an identifier of a second link between the STA and the AP that operates in the second channel, a second uplink / downlink availability field for carrying an indication of whether uplink transmission is available over the second link and an indication of whether downlink transmission is available over the second link, a first relay link identifier field for carrying an identifier of a first relay link between the STA and a relay STA that operates in the first channel, and / or a second relay link identifier field for carrying an identifier of a second relay link between the STA and a relay STA that operates in the second channel.

[0191] In an embodiment, when the current MLO relay supportability type for the STA is the first MLO relay supportability type, the first relay link identifier field and the second relay link identifier field are not used. In an embodiment, when the current MLO relay supportability type for the STA is the second MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is available over the second link and an indication that downlink transmission is available over the second link. In an embodiment, when the current MLO relay supportability type for the STA is the third MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is available over the second link. In an embodiment, when the current MLO relay supportability type for the STA is the fourth MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is unavailable over the second link. In an embodiment, when the current MLO relay supportability type for the STA is the fifth MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is unavailable over the first link and an indication that downlink transmission is unavailable over the first link and the second uplink / downlink availability field carries an indication that uplink transmission isunavailable over the second link and an indication that downlink transmission is unavailable over the second link. In an embodiment, the relay supportability update request message is relayed by a relay STA to the AP. In an embodiment, the relay supportability update request message is delivered to the AP without using relay operations.

[0192] At operation 2620, the STA receives, as a response to the relay supportability update request message, a relay supportability update response message from the AP indicating that the AP has stored the updated MLO relay supportability information for the STA. In an embodiment, the AP configures the STA, a relay STA, and / or itself to operate in accordance with the current MLO relay supportability type for the STA in response to receiving the relay supportability update request message.

[0193] Turning now to Figure 27, a method 2700 will be described for obtaining MLO relay supportability information, in accordance with an example embodiment. The method 2700 may be performed by an AP. The AP may be implemented by a wireless device (e.g., wireless device 104).

[0194] At operation 2705, the AP receives a relay supportability update request message from the STA that includes updated MLO relay supportability information for the STA (e.g., which may include the information mentioned above with regard to operation 2615 of Figure 26).

[0195] At operation 2710, the AP stores the updated MLO relay supportability information for the STA.

[0196] At operation 2715, the AP transmits, as a response to the relay supportability update request message, a relay supportability update response message to the STA indicating that the AP has stored the updated MLO relay supportability information for the STA.

[0197] Turning now to Figure 28, a method 2800 will be described for providing link quality information, in accordance with an example embodiment. The method 2800 may be performed by a STA to provide link quality information to an AP. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0198] At operation 2805, the STA receives a first frame transmitted by the AP.

[0199] At operation 2810, the STA receives a second frame transmitted by a relay STA, wherein the relay STA transmitted the second frame in response to receiving the first frame from the AP. In an embodiment, the first frame is a PS-Poll frame and the second frame is a null data frame.

[0200] In an embodiment, at operation 2815, responsive to receiving the first frame or the second frame, the STA transmits a third frame to the AP to allow the AP to measure uplink link quality.

[0201] At operation 2820, the STA determines a link quality of a first link between the STA and the AP based on the first frame.

[0202] At operation 2825, the STA determines a link quality of a second link between the STA and the relay STA based on the second frame. In an embodiment, the link quality of the first link and the link quality of the second link are determined using CSI, received signal strength indication (RSSI), SNR, and / or CQI.

[0203] At operation 2830, the STA transmits a link quality measurement report message to the AP that includes an indication of the link quality of the first link and an indication of the link quality of the second link.

[0204] Turning now to Figure 29, a method 2900 will be described for determining that a MLO relay supportability type for a STA should be changed, in accordance with an example embodiment. The method 2900 may be performed by an AP. The AP may be implemented by a wireless device (e.g., wireless device 104).

[0205] At operation 2905, the AP transmits a first frame to a relay STA that causes the relay STA to transmit a second frame. In an embodiment, the first frame is a PS-Poll frame and the second frame is a null data frame.

[0206] At operation 2910, the AP receives a link quality measurement report message from the STA that includes an indication of a link quality of a first link between the STA and the AP and an indication of a link quality of a second link between the STA and the relay STA, wherein the STA determined the link quality of the first link based on the first frame and the STA determined the link quality of the second link based on the second frame.

[0207] At operation 2915, the AP determines that the MLO relay supportability type for the STA should be changed based on the link quality of the first link and the link quality of the second link indicated in the link quality measurement report message.

[0208] In an embodiment, at operation 2920, responsive to determining that the MLO relay supportability type for the STA should be changed, the AP configures the STA, the relay STA, and / or the AP to operate in accordance with a new MLO relay supportability type for the STA.

[0209] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein maybe or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one or more data processing components (generically referred to here as a “processor” or “processing unit”) to perform the operations described herein. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines). Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0210] In some cases, an embodiment may be an apparatus (e.g., an AP STA, a non-AP STA, or another network or computing device) that includes one or more hardware and software logic structures for performing one or more of the operations described herein. For example, as described herein, an apparatus may include a memory unit, which stores instructions that may be executed by a hardware processor installed in the apparatus. The apparatus may also include one or more other hardware or software elements, including a network interface, a display device, etc.

[0211] Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consi stent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

[0212] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

[0213] 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 ageneral -purpose computer selectively activated or reconfigured by a computer program stored in the computer. For example, a computer system or other data processing system may carry out the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

[0214] The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general -purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

[0215] The present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). In some embodiments, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory components, etc.

[0216] In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Claims

CLAIMSWhat is claimed is:

1. A method performed by a station (STA) that has multi-link operation (MLO) capability to provide MLO relay supportability information to an access point (AP), the method comprising: detecting a change in a MLO relay supportability type for the STA from a previous MLO relay supportability type for the STA to a current MLO relay supportability type for the STA; responsive to detecting the change, transmitting a relay supportability update request message to the AP that includes updated MLO relay supportability information for the STA; and receiving, as a response to the relay supportability update request message, a relay supportability update response message from the AP indicating that the AP has stored the updated MLO relay supportability information for the STA.

2. The method of claim 1, wherein the current MLO relay supportability type for the STA is any one of: a first MLO relay supportability type, a second MLO relay supportability type, a third MLO relay supportability type, a fourth MLO relay supportability type, and a fifth MLO relay supportability type, wherein the first MLO relay supportability type is a relay supportability type where the STA and the AP can communicate with each other directly in a first channel and a second channel and do not communicate with each other using relay operations in the first channel and the second channel, wherein the second MLO relay supportability type is a relay supportability type where the STA and the AP can communicate with each other directly in the first channel and the second channel and can also communicate with each other using relay operations in the first channel and the second channel, wherein the third MLO relay supportability type is a relay supportability type where the STA and the AP can communicate with each other directly in the first channel, the AP can communicate directly to the STA in the second channel, and the STA does not communicate to the AP directly in the second channel but can communicate to the AP using relay operations in the second channel, wherein the fourth MLO relay supportability type is a relay supportability type where the STA and the AP can communicate with each other directly in the first channeland do not communicate with each other directly in the second channel but can communicate with each other using relay operations in the second channel, and wherein the fifth MLO relay supportability type is a relay supportability type where theSTA and the AP do not communicate with each other directly in the first channel and the second channel but can communicate with each other using relay operations in the first channel and the second channel.

3. The method of claim 2, wherein the relay supportability update request message includes a relay supportability type field that carries an indication of the current MLO relay supportability type for the STA.

4. The method of claim 3, wherein the relay supportability update request message further includes: a first direct link identifier field for carrying an identifier of a first link between the STA and the AP that operates in the first channel, a first uplink / downlink availability field for carrying an indication of whether uplink transmission is available over the first link and an indication of whether downlink transmission is available over the first link, a second direct link identifier field for carrying an identifier of a second link between the STA and the AP that operates in the second channel, a second uplink / downlink availability field for carrying an indication of whether uplink transmission is available over the second link and an indication of whether downlink transmission is available over the second link, a first relay link identifier field for carrying an identifier of a first relay link between the STA and a relay STA that operates in the first channel, and a second relay link identifier field for carrying an identifier of a second relay link between the STA and a relay STA that operates in the second channel.

5. The method of claim 4, wherein when the current MLO relay supportability type for the STA is the first MLO relay supportability type, the first relay link identifier field and the second relay link identifier field are not used.

6. The method of claim 4, wherein when the current MLO relay supportability type for the STA is the second MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlinkavailability field carries an indication that uplink transmission is available over the second link and an indication that downlink transmission is available over the second link.

7. The method of claim 4, wherein when the current MLO relay supportability type for the STA is the third MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is available over the second link.

8. The method of claim 4, wherein when the current MLO relay supportability type for the STA is the fourth MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is available over the first link and an indication that downlink transmission is available over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is unavailable over the second link.

9. The method of claim 4, wherein when the current MLO relay supportability type for the STA is the fifth MLO relay supportability type, the first uplink / downlink availability field carries an indication that uplink transmission is unavailable over the first link and an indication that downlink transmission is unavailable over the first link and the second uplink / downlink availability field carries an indication that uplink transmission is unavailable over the second link and an indication that downlink transmission is unavailable over the second link.

10. The method of claim 2, wherein the first channel is in a 2.4 Gigahertz (GHz) band and the second channel is in a 5 GHz band.

11. The method of claim 1, wherein the relay supportability update request message is relayed by a relay STA to the AP.

12. The method of claim 1, wherein the relay supportability update request message is delivered to the AP without using relay operations.

13. The method of claim 1, wherein the AP configures the STA, a relay STA, and / or itself to operate in accordance with the current MLO relay supportability type for the STA in response to receiving the relay supportability update request message.

14. A method performed by a station (STA) that has multi-link operation (MLO) capability to provide link quality information to an access point (AP), the method comprising: receiving a first frame transmitted by the AP; receiving a second frame transmitted by a relay STA, wherein the relay STA transmitted the second frame in response to receiving the first frame from the AP; determining a link quality of a first link between the STA and the AP based on the first frame; determining a link quality of a second link between the STA and the relay STA based on the second frame; and transmitting a link quality measurement report message to the AP that includes an indication of the link quality of the first link and an indication of the link quality of the second link.

15. The method of claim 14, wherein the first frame is a power save polling (PS-Poll) frame and the second frame is a null data frame.

16. The method of claim 14, wherein the link quality of the first link and the link quality of the second link are determined using channel state information (CSI), received signal strength indication (RSSI), signal -to-noise ratio (SNR), and / or channel quality indicator (CQI).

17. The method of claim 14, further comprising: responsive to receiving the first frame or the second frame, transmitting a third frame to the AP to allow the AP to measure uplink link quality.

18. A method performed by an access point (AP) to determine whether a multi-link operation (MLO) relay supportability type for a station (STA) having MLO capability should be changed, the method comprising: transmitting a first frame to a relay STA that causes the relay STA to transmit a second frame; receiving a link quality measurement report message from the STA that includes an indication of a link quality of a first link between the STA and the AP and an indication of a link quality of a second link between the STA and the relay STA, wherein the STA determined the link quality of the first link based on the first frame and the STA determined the link quality of the second link based on the second frame; anddetermining that the MLO relay supportability type for the STA should be changed based on the link quality of the first link and the link quality of the second link indicated in the link quality measurement report message.

19. The method of claim 18, wherein the first frame is a power save polling (PS-Poll) frame and the second frame is a null data frame.

20. The method of claim 18, further comprising: responsive to determining that the MLO relay supportability type for the STA should be changed, configuring the STA, the relay STA, and / or the AP to operate in accordance with a new MLO relay supportability type for the STA.

21. A wireless device to implement a station (STA), the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the STA to perform the method of any one of claims 1-17.

22. A wireless device to implement an access point (AP), the wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the AP to perform the method of any one of claims 18-20.

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