Methods for determining relay operation modes

Abstract

In some aspects, the techniques described herein relate to a method, including: in an access point (AP) device, wirelessly transmitting one or more control frames to a relay device to acquire relay transmission parameters for relay operations between the AP device and a destination station (dSTA) device through the relay device; comparing AF (amplify and forward) and DF (decode and forward) performance functions using the acquired relay transmission parameters; and selecting one of an AF and DF relay transmission modes based on the compared AF and DF performance functions.

Description

SPECIFICATIONMETHODS FOR DETERMINING RELAY OPERATION MODESCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 589,752 filed October 12, 2023, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to relay forwarding modes in a wireless network.BACKGROUND

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

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

[0005] The disclosure will be more fully understood from the detailed description provided below and the accompanying drawings that depict various embodiments of the disclosure. However, these drawings should not be interpreted as limiting the disclosure to the specific embodiments shown; they are provided for explanation and understanding only.

[0006] Figure 1 A is a diagram showing a single BSS with an AP and multiple non-AP STAs in accordance with some embodiments.

[0007] Figure IB is a table illustrating operational parameters for various WiFi versions leading up to 802.1 Ibn.

[0008] Figure 2 is a block diagram illustrating a wireless device in accordance with some embodiments.

[0009] Figure 3 A is a diagram illustrating components of a WLAN device configured to transmit data in accordance with some embodiments.

[0010] Figure 3B is a diagram illustrating components of a WLAN device configured to receive data in accordance with some embodiments.

[0011] Figure 4 is a diagram illustrating Inter-Frame Space (IF S) relationships for WiFi transmissions in accordance with some embodiments.

[0012] Figure 5 is a diagram illustrating a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collisions between frames in a channel in accordance with some embodiments.

[0013] Figure 6A is a diagram showing the general structure of a trigger frame in accordance with some embodiments.

[0014] Figure 6B is a diagram showing how resource units may be distributed for multiple users in an OFDMA transmission in accordance with some embodiments.

[0015] Figure 6C is a diagram illustrating an example trigger frame uplink (UL) transmission scenario in accordance with some embodiments.

[0016] Figure 6D illustrates an example trigger frame downlink (UL) transmission scenario in accordance with some embodiments.

[0017] Figures 7A and 7B show the general structures for EHT (WiFi 7) multi user and trigger based physical layer protocol data unit (PPDU) frames, respectively, in accordance with some embodiments.

[0018] Figure 7C is a table listing the fields and associated information for a TB PPDU in accordance with some embodiments.

[0019] Figure 7D is a table listing descriptions and information for sub fields in a universal signal (U-SIG) field for either a MU or TB PPDU frame in accordance with some embodiments.

[0020] Figures 8A and 8B are diagrams showing network stations using relay techniques for transmitting packets in accordance with some embodiments.

[0021] Figure 9A is a flow diagram showing a method for an AP to select a relay mode in accordance with some embodiments.

[0022] Figure 9B is a flow diagram showing a routine 920, from the perspective of a relay device, for acquiring AF / DF mode parameter information in accordance with some embodiments.

[0023] Figures 10 and 11 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with some embodiments.

[0024] Figures 12 and 13 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with some additional embodiments.

[0025] Figures 14 and 15 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with yet additional embodiments.

[0026] Figure 16 is a diagram showing exemplary frame sequences between the AP, relay and dSTA when data is forwarded using an AF mode in accordance with some embodiments.

[0027] Figure 17 is a diagram showing exemplary frame sequences between the AP, relay and dSTA when data is forwarded using a DF mode in accordance with some embodiments.

[0028] Figure 18 is a diagram showing exemplary frame sequences between an AP, relay and a dSTA when data is forwarded using a DF mode in accordance with some other embodiments.

[0029] Figure 19 is a diagram showing exemplary frame sequences between an AP, relay and a dSTA when data is forwarded using an AF mode in accordance with yet additional embodiments.

[0030] Figure 20 is a diagram showing transactions between an AP, a relay, and a dSTA for the AP to obtain parameters and select an DF mode in accordance with some embodiments.DETAILED DESCRIPTION

[0031] As mentioned above, some of the objectives of the next generation of wireless networking standards (e.g., IEEE 802.1 Ibn or beyond IEEE 802.1 Ibe) include improving data rate and communication range. With recent developments in IEEE 802.11 standards, relay operations can provide improvements with reliability and throughput. AF (Amplify-and- Forward) and DF (Decode-and-Forward) relay modes are two distinct cooperative relaying protocols used in wireless communication systems to enhance signal transmission between a source and a destination. In the AF mode, the relay node receives the incoming signal from the source and amplifies it before forwarding it to the destination. This process does not involve decoding the signal; instead, the relay simply boosts the received signal's strength. This method is beneficial in scenarios where the relay has limited processing capabilities or when low latency is crucial. However, one downside is that any noise present in the received signal is also amplified, which can degrade the overall signal quality at the destination. Conversely, in the DF mode, the relay first decodes the received signal from the source before re-encoding and forwarding it to the destination. This process allows for error correction and generally results in improved performance compared to AF, particularly in terms of reducing noise propagation. The DF protocol is more complex as it requires additional processing at the relay, but it typically offers better reliability and higher achievable data rates.

[0032] Either type of STA (non-AP or AP) can act as a relay device. Relay devices can operate using the AF mode, the DF mode, or either AF or DF modes. When the relay device can operate in either AF or DF mode, techniques are needed for selection of the proper mode based on relevant relay operation parameters. Techniques may also be needed to effectively control a relay device to obtain and make available such parameters and to carry out the selected relay forwarding mode. In some embodiments, an AP can obtain relevant parameters from a relay device and compare expected receiving performances of the destination STA (dSTA) for relay operations in AF and DF modes to select a preferred mode. By comparing expected performances between AF and DF modes, an AP can select the particular forwarding mode and indicate it to the relay device.

[0033] 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 withoutdeparting 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.

[0034] Figure 1 A shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104). Each of the wireless devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments(e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In 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.

[0035] 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).

[0036] Figure IB is a table illustrating operational parameters for various WiFi versions leading up to 802.1 Ibn, also referred to as WiFi 8 or UHR (Ultra High Reliability). The IEEE 802.1 Ibn (UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi. As shown in Figure IB, the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video- over- WLAN, gaming, AR, and VR. It is noted that various characteristics of UHR (e.g., max PHY rate, PHY rate enhancement, bandwidth / number of spatial streams, and operating bands) are still being considered.

[0037] The focus of IEEE 802.1 Ibe (EHT or WiFi 7) is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands. In addition to peak PHY rate, different candidate features are under discussion. These candidate features include (1) a 320 MHz bandwidth and a more efficient utilization of a noncontiguous spectrum, (2) multi -band / multi -channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.

[0038] 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.

[0039] 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.

[0040] With respect to operational bands (e.g., 2.4 / 5 / 6 GHz) for IEEE 802.1 Ibe, more than 1 GHz of additional unlicensed spectrum is likely to be available because the 6 GHz band (5.925 - 7.125 GHz) is being considered for unlicensed use. This would allow APs and STAs to become tri-band devices. Larger than 160 MHz data transmissions (e.g., 320 MHz or 640 MHz) could be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160MHz data could be transmitted in the 6 GHz band. For example, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0041] 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.

[0042] Figure 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment. The wireless device 104 may be the wireless device 104A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1. The wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the inputinterfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The antenna unit 250 includes one or more antennas. When Multiple-Input Multiple- Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antenna unit 250 may include a plurality of antennas. In an embodiment, the antennas in the antenna unit 250 may operate as abeam-formed antenna array. In an embodiment, the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] The interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein. The interleaver 302 may apply the interleaving only when theencoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0066] 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.

[0067] 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.

[0068] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBC decoder for de-spreading the constellation points from the space-time streams into one or more spatial streams.

[0069] The demapper 314 de-maps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone de-mapping before performing the constellation de-mapping.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an Access Category (AC) ‘i’ (AIFS[i]). Figure 4 also illustrates a slot time and a data frame is used for transmission of data forwarded to a higher layer. As shown, a WLAN device 104 transmits thedata frame after performing backoff if a DIFS has elapsed during which the medium has been idle.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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 second station STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received. The stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.

[0085] 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.

[0086] 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).

[0087] 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.

[0088] 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 framehas 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.

[0089] 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.

[0090] 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.

[0091] Figure 6A is a diagram showing the general structure of a trigger frame. A trigger frame is a control frame whose function is to allocate resources and solicit one or more Triggerbased (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from associated stations including both AP and / or non-AP STAs.

[0092] With additional reference to Figure 6B, among other things, trigger frames may be used by APs to allocate resources for multi-user Orthogonal Frequency Division Multiple Access (OFDMA) transmissions. They specify how bandwidth and time slots should be divided among multiple STAs, enabling simultaneous data transmission from multiple users without interference. This can be beneficial for improving overall network efficiency and throughput, especially in environments with high user density.

[0093] In this disclosure, multi-user (MU) transmission refers to cases that multiple frames are transmitted to or from multiple STAs simultaneously using different resources, wherein examples of different resources are different frequency resources in OFDMA transmission and different spatial streams in MU-MIMO transmission. DL-OFDMA, DL-MU-MIMO, UL- OFDMA, UL-MU-MIMO and OFDMA with MU-MIMO are examples of MU transmissions.

[0094] As illustrated in Figure 6A, trigger frames generally include several different sections including a MAC (media access control) header section 605, a common information section 610, and a user information section 615. The MAC header includes several fields that facilitate communication between devices. For example, they may include Frame Control (FC), Duration (or Duration / ID), Receiver Address (RA), and Transmitter Address (TA) fields as shown. TheFC field indicates protocol Version, type, and several different flags for parameters such as power management. The duration field indicates the duration for which the medium is reserved, or in some implementations, it may carry the association identifier (AID) in certain contexts. The RA field indicates the address of a recipient STA, and the TA field indicates the address of the transmitting STA. The MAC header may also include fields for sequence and QoS Control.

[0095] Trigger frames have specific subfields within the frame Control field that are used for its operation including the trigger frame type, e.g., basic trigger, MU-BAR (multi-user block acknowledgment request, and MU-RTS (multi-user request to send. Each of these subtypes has unique characteristics and requirements for operation, especially in multi-user scenarios where coordination is important for efficient communication.

[0096] The common Info section 610 includes parameters such as the expected uplink length, bandwidth, guard interval, and the transmit power used by the AP. These parameters help STAs prepare for their upcoming transmissions.

[0097] The different fields in the common info field serve to inform the responding STAs on how they should set up the frame in the response. The response to a MU-RTS is a legacy CTS frame in the non-HT format. At 5GHz that means legacy OFDM. Most of the subfields in the common info field for MU-RTS may therefore not be needed. For the included fields, trigger type is set to 3 for MU-RTS requests; More TF is used for TWT or power save with UORA (otherwise set to 00; and the CS Required is set to 0 if the responding STAs are not required to consider the medium or the NAV in determining whether or not to respond. CS Required is set to 1 if responding STAs are required to use ED (Energy Detect) to sense and consider the medium and the NAV in determining whether or not to respond. The UL BW is usually used to describe the bandwidth of the response in the TB PPDU, but for MU-RTS, it may describe the bandwidth of the frame carrying the MU-RTS (e.g., 0=20 MHz, 1=40 MHz, 2=80 MHz, and 3=80 + 80 MHz or 160 MHz).

[0098] The user info section 615 includes details for each participating STA, such as Association IDs (AIDs), Resource Unit (RU) allocations, Modulation and Coding Scheme (MCS), and an expected Received Signal Strength Indicator (RSSI). This information allows each STA to know its specific transmission parameters. The AID12 field indicates the STA-id (associations ID) for each recipient. Other values used in this space are used in other variants of the trigger frame. RU allocation is used to indicate which primary channel the responding CTS should be sent on. This is particular to 40 MHz and 80 MHZ channels, whether the primary channel are the lowest channel, next lowest channel, and so on. The user info fields are typically repeated for every STA that is a recipient of the MU-RTS. The receiving STAs are addressed bytheir association ID, STA-id, not by MAC-addresses as in legacy RTS. There may be other information depending on specific trigger frame types. The User Info field in a trigger frame, such as in a MU-RTS trigger frame, may also include an allocation duration subfield. This subfield indicates a time allocated by the AP for the STA to transmit during the TXOP. The field can contain an allocation duration subfield, which indicates the duration of time allocated for P2P communications associated with the client device. This allocation duration subfield is used for managing the transmission time and allowing other devices to set their network allocation vectors (NAVs) accordingly.

[0099]

[0100] Figure 6C illustrates an example trigger frame uplink (UL) transmission scenario in accordance with some embodiments. In the IEEE 802.11 specification versions since 802.1 lax (WiFi 6), the trigger frame plays a useful role in facilitating both uplink and downlink multi-user (MU) transmissions.

[0101] 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.

[0102] With the example scenario of Figure 6B, an access point (AP) operating in an 80 MHz bandwidth environment sends a trigger frame to multiple associated STAs to allow them to perform uplink data transmissions. Upon receiving the Trigger frame, the STAs respond by sending their respective CTS response frames. CTS (clear to send) frames are the response to a MU-RTS. All STAs that are addressed in the user info field of a MU-RTS trigger frame should respond with a CTS if they wish to participate in an uplink transmission. When the STAs send their CTS, they use the TA address, the address of the STA (AP) that should receive the CTS. The AP then sends a transmission to initiate uplink transmission from the STAs that responded appropriately. From here, the STAs transmit orthogonal frequency division multiple access (UL OFDMA) TB PPDUs utilizing the allocated resources within the specified 80 MHz bandwidth. After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame. This acknowledgement can be in the form of an 80 MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method. The multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.

[0103] Figure 6C illustrates an example trigger frame downlink (DL) transmission scenario in accordance with some embodiments. It’s similar to the uplink procedure except it facilitates bulk data transmissions from the AP to the STAs rather than from the STAs to the AP. The AP sends to the STAs a multi user RTS, e.g., MU-RTS-TXS for request to send downlink transmissions to the STAs. The process begins with the AP sending a MU RTS TXS trigger frame to the non-AP STA(s). Upon receiving this frame, the STAs are expected to respond with a CTS frame, indicating that they are ready to receive the data. From here, the AP transmits to the STAs that responded MU PPDUs, which include data intended for the STAs. Finally, the STAs respond with acknowledgement frames back to the AP.

[0104] Figures 7A and 7B show the general structures for EHT (WiFi 7) multi user and trigger based physical layer protocol data unit (PPDU) frames, respectively. (It is expected that the UHR PPDUs will be the same or similar. For simplicity, EHT examples may be used here and in other parts of this disclosure, but it should be appreciated that UHR and later specification parameters may equally be implemented.) With reference to Figure 7A, a MU PPDU can be sent to a single user or to multiple users. The frame has legacy (705 A) and contemporary (710A) preamble sections, along with data and packet extension field sections. The legacy section includes a legacy short training field (L-STF), legacy long training field (L-LTF) and a legacy signal field (L-SIG). The contemporary section includes a universal signal field (U-SIG), an EHT signal field (EHT-SIG), an EHT short training field (EHT-STF), an EHT long training field (EHT-LTF), data fields for the actual data payload, and a packet extension (PE) field. The EHT-SIG field, along with the U-SIG field, provides RU (resource unit) allocations and other information the STAs need to understand the MU packet. When the MU PPDU is sent to multiple users, the transmission can be OFDMA or MU-MIMO.

[0105] With reference to Figure 7B, upon receiving a trigger based RTS from an AP, a STA may use the EHT TB PPDU to respond to the trigger from the AP. The EHT TB frame format is similar to the MU PPDU. However, the TB PPDU does not include the EHT-SIG preamble field, and it includes a repeated legacy (RL) signal field in the legacy section. In addition, the EHT-STF field may be two times longer than in the EHT MU PPDU in order to improve performance and reliability for uplink transmissions. Figure 7C is a table listing the fields, along with additional information, for a TB PPDU. Figure 7D is a table listing descriptions and information for sub fields in a universal signal (U-SIG) field for either a MU or TB PPDU frame.

[0106] The preamble is a design component used to provide information relevant for the receiver to decode the transmitted data. It is also used to provide backward compatibility withprevious PHY versions. However, the preamble typically does not directly conveyed the PHY version of the packet. Auto detection (or spoofing) mechanisms have been created for receivers to implicitly determine the PHY versions. However, the auto detection algorithms have had to become more complex. EHT attempts to solve this problem with the universal signal (U-SIG) field. The U-SIG comes after the legacy and RL SIG fields and is 2 OFDM symbols in length. It includes version independent and version dependent bits. The version independent bits are the first 20 bits of the U-SIG and have the same location and definition for EHT and later PHYs. The first 3 bits (bits 0 to 2) are used to identify the PHY version, which simplifies auto detection. The next 3 bits (bits 3 to 5) indicate the spectrum occupancy of the PPDU (e.g., 80 MHz bandwidth). The 7th bit (bit 6) signals the link direction (i.e., uplink or downlink). The next 6 bits (bits 7 to 12) identify the basic service set (BSS) in use via the BSS color and the 7 TXOP bits (bits 13 to 19) provide information on how long the PPDU uses the medium. The U- SIG bits / fi elds remainder depends on the PHY version and PPDU type.

[0107] To provide flexibility and prepare for possible new capabilities, EHT classifies the reserved bits in the EHT preamble as "disregard" or "validate". This classification helps a receiver determine the appropriate action if it comes across a bit value that is not used in a PHY it supports. Disregard means ignore this bit and continue reception. Validate means check if the bit matches a known value and if not, terminate reception. As an example, values 1 to 7 in the PHY version identifier field will correspond to a future IEEE802.11 PHY version not recognized by a device supporting the current EHT version. If a baseline EHT device receives a value other than 0 (0 indicates EHT PHY), the device should stop reception.

[0108] 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.

[0109] 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 tomake 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.

[0110] 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.

[0111] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmitted subpacket. IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. The SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket. Self-decoding is possible when the receiving signal- to-noise ratio (SNR) environment is good (i.e., a high SNR). In some embodiments, subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0112] 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 desired.

[0113] In the context of coordinated TDMA (C-TDMA), the AP that has 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.

[0114] Various different M-AP technologies have been, and are being, discussed. They include coordinated beamforming (CBF), coordinated spatial reuse (CSR), joint transmission (JTX), and OFDMA / TDMA. Coordinated beam-forming / nulling involves multiple APs transmitting on the same frequency resource based on the coordination and formation of spatial nulls to allow for simultaneous transmission from multiple APs. Interference between the M- APs is reduced through the sharing of channel state information (CSI). With coordinated spatial reuse (C-SR), multiple APs and / or STAs adjust the transmit power to reduce interference between stations (APs, non-AP STA). With joint transmission (JTX) schemes, multiple APs jointly transmit to a given user simultaneously by sharing data between the APs. In effect, the multiple APs act as a single, virtual AP. With coordinated OFDMA / TDMA schemes, M-APs use time and frequency in a cooperative manner to increase system throughput. They transmit on orthogonal frequency resources by coordinating and splitting the spectrum to use it more efficiently.

[0115] Figures 8 A and 8B are diagrams showing network stations using relay techniques for transmitting packets. IN this example, there is a source station (sSTA) 810, a relay 820 and a destination STA (dSTA) 830. The sSTA is an AP in this example, acting as a source node. The relay device 820 may be an AP or non-AP STA, and the dSTA, which also may be an AP or non-AP STA, acts as a destination (or recipient) node. For convenience and ease of understanding, going forward, the sSTA will simply be referred to as an AP.

[0116] With this example, the AP, relay and dSTA have the same BSS color. However, it should be appreciated that the concepts discussed herein can be expanded to when the relay or / and dSTA have different BSS colors than the AP. For this example scenario, it is assumed that were the AP to transmit a PPDU directly to the dSTA, the wireless link would not be able to facilitate desired MCS (Modulation and Coding Schemes) and throughput, as a result at least due to a low SNR (signal to noise ratio)from the AP to the dSTA, e.g., as a result of obstacles such as blockages or a lengthy distance. Moreover, the dSTA may not be able to successfully transmit PPDUs directly to the AP due, for example, to having relatively lower power than theAP. Thus, in order to increase reliability and throughput, the AP may instead transmit PPDUs to the dSTA by using the relay. However, when the relay has the capability of using both AF and DF modes, a method is needed to control the relay to use the most suitable option, depending on various different factors. In some embodiments, potential performance based on conditions such as a performance function for each mode may be compared in order to select a preferred mode for a given situation.

[0117] Figure 9A is a flow diagram showing a method for an AP to select a relay mode in accordance with some embodiments. At 902, an AP device wirelessly Transmits one or more control frames to a relay device to acquire AF (amplify and forward) and DF (decode and forward) relay mode parameters for the relay device and the dSTA device. In some embodiments, the parameters include a first set of channel information parameters associated with relay transmission between the AP device and the relay device. The parameters may also include a second set of channel information parameters associated with relay transmission between the relay device and the dSTA device.

[0118] Channel information indicates the quality of a wireless channel between two stations. Channel information may include channel state information (CSI) and / or CQI (channel quality indicators). CSI is typically expressed using a so-called “H” matrix, a complex-valued matrix that represents the channel between the transmitter and receiver. It includes matrix elements (e.g., hp, q(f,t)) that describe channel component propagation characteristics between antenna elements of the transmitter to antenna elements of the receiver for given subcarriers and units in time. The H parameters are typically estimated at the receiver using known pilot or training signals. The first set of parameters may be obtained in any suitable manner. In some implementations, they can be retrieved from receiver feedback from the relay (e.g., from a beam forming report). In other embodiments, the AP can estimate channel information from a received transmission from the relay using channel reciprocity. For example, H parameters between the relay and the AP device may be retrieved by the AP from the relay by transmitting a null data packet announcement (NDPA) frame to the relay device, transmitting a null data packet (NDP) to the relay device, and then receiving a beam forming report (BFR) that includes the channel information parameters for the AP -relay channel from the relay device. Alternatively, the AP device may transmit a null data packet announcement (NDPA) frame to the relay device, receive a null data packet (NDP) from the relay device, and then using channel reciprocity on the received NDP frame, generate channel information for the AP-relay channel.

[0119] (Note that with recent WiFi protocols, beamforming may be enabled through a process called channel sounding. The beamformer (typically an AP) initiates this process bytransmitting a Null Data Packet Announcement (NDPA) frame. The NDPA identifies the intended beam formee(s) and specifies parameters for the channel sounding feedback. After the NDPA, the beamformer sends a Null Data Packet (NDP), which is an empty PPDU frame used by the beam formee(s) to measure the channel and provide feedback. The recipient analyzes the training fields in the NDP to estimate the channel information matrix (H) and compresses it into a compressed beamforming report. The beam formee(s) respond to the NDP or BFRP with a compressed beamforming report containing a matrix of angles that represents the estimated channel. This report instructs the beamformer how to steer the signal toward the beam formee(s) for higher SNR).

[0120] (Note that channel reciprocity refers to the principle that the uplink (UL) and downlink (DL) channels in a time-division duplex (TDD) system are essentially the same under certain conditions. This property is useful for optimizing communication systems, especially in multiple-input multiple-output (MIMO) setups. Channel reciprocity allows for the use of channel state information (CSI) obtained from the uplink to predict the downlink channel characteristics. This is particularly beneficial in MIMO systems where accurate CSI is helpful for maximizing throughput and minimizing interference. However, achieving perfect channel reciprocity can be challenging due to various factors such as hardware imperfections, environmental changes, and mobility of users. A Null Data Packet (NDP) can be used as a training frame to facilitate channel estimation. The process involves the transmitter sending a VHT NDP Announcement frame to inform the receiver about the upcoming NDP transmission. Following a short inter-frame space (SIFS), the transmitter sends the NDP, which contains no data but includes training symbols. These symbols are used for estimating the MIMO channel between the transmitter and receiver. Upon receiving the NDP, the receiver uses the training symbols to estimate the channel response. If channel reciprocity holds, this estimate can be effectively used for both uplink and downlink transmissions.)

[0121] In some embodiments, the AP can obtain the second set of CSI parameters for a channel between the relay and dSTA by causing the relay device to obtain the second set of CSI parameters from one or more frames from the dSTA device and then receive the second set of CSI parameters from the relay device. For example, in some embodiments, the AP device may transmit a first null data packet announcement (NDPA) frame to the relay device, transmit a null data packet (NDP) to the relay device, and receive a beam forming report such as a compressed beam forming report (cBFR) from the relay device that includes CSI for the relay-dSTA channel. In other embodiments, the AP device may cause the relay device to obtain the second set of CSI parameters from one or more frames from the dSTA by transmitting a variant triggerframe to the relay device. In some embodiments, the variant trigger frame causes the relay device to send to the dSTA device an NDP frame to cause the dSTA device to send back to the relay a beam forming report (BFR) with CSI for the relay-dSTA channel. This information is then sent back to the AP, either separately or as part of a report that also includes CSI for the AP-relay channel. In some embodiments, the variant trigger frame could cause the relay device to send an NDP back to the AP device for it to get reciprocal channel CSI information for the AP-relay channel. In some embodiments, the variant trigger frame causes the relay device to send a NFRP (NDP feedback report poll) frame to the dSTA device to cause it to send back to the relay device an NDP frame so that the relay device can obtain the second set of CSI parameters through the NDP frame using channel reciprocity.

[0122] (Note that NFRP refers to the **NDP Feedback Report Poll**. This report is part of the Wi-Fi communication protocols, particularly used in the context of **0FDMA (Orthogonal Frequency Division Multiple Access)**. The NFRP is a mechanism that allows access points (APs) to send feedback regarding the status of data transmission, particularly in multi-user environments. It helps in optimizing the wireless communication by providing information on bandwidth usage and network performance. Among other things, the NFRP enables APs to gather feedback from connected devices about their data transmission status, which can be useful for managing network resources effectively.)

[0123] In some embodiments, a variant trigger frame may be sent to the relay device to receive back from it a second set of feedback parameters including a gain (G) for relay transmission from the relay to the dSTA using the AF mode. In some embodiments, the AP may determine a first power parameter using the first set of channel information parameters where the first power parameter is associated with relay transmission between the relay device and the AP device. In some embodiments, the AP may receive feedback for the dSTA from the relay where the feedback includes a second power parameter associated with relay transmission between the relay device and the dSTA device for the DF mode. In some embodiments, the second power parameter includes min and max power parameters for relay transmissions between the relay device and the dSTA device.

[0124] Returning to the flow diagram of Figure 9A, at 904, AF and DF performance functions are compared using the acquired first and second set parameters. In some embodiments, the AF performance function is based on a combination of the first power parameter, the gain (G), and the first set of channel information parameters. In some embodiments, the DF performance function is based on a combination of the second powerparameter and the second set of channel information parameters. At 906, either the AF or DF relay modes are selected based on the compared performance functions.

[0125] Figure 9B is a flow diagram showing a routine 920, from the perspective of a relay device, for acquiring AF / DF mode parameter information in accordance with some embodiments. At 922, the relay device receives a first control frame from an access point (AP) device. At 924, the relay device transmits a second control frame to a destination station (dSTA) device in response to the first control frame. At 926, the relay device obtains relay-dSTA channel information parameters from the dSTA device based on a response frame from the dSTA device. For example, in some embodiments, it may obtain the relay-dSTA channel information parameters from a beam forming report. IN other embodiments, it may obtain the relay-dSTA channel information parameters by generating it using channel reciprocity for a first NDP frame received from the dSTA.

[0126] In some embodiments, the relay device may receive a first null data packet (NDP) from the AP device and send to the AP device an AP-relay beam forming report (BFR) that includes relay transmission parameters associated with amplify-forward (AF) downlink transmissions from the AP device to the relay device. In some embodiments, it may receive a first null data packet announcement (NDP A) frame from the AP device send a null data packet (NDP) to the AP device suitable for the AP device to use channel reciprocity on the received NDP to generate channel information parameters associated with transmissions from the AP device to the relay device. Finally, at 928, the relay device provides to the AP device a relay- dSTA power parameter based on the relay-dSTA channel information parameters.

[0127] Figures 10 and 11 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with some embodiments. With this approach, the AP obtains the parameters using feedback from the relay device. In some embodiments, the feedback parameters include downlink (DL) Hl channel information such as channel state information (CSI) and channel quality indicators (CQI) between the AP and the relay.

[0128] It may also obtain H2 channel information such as downlink channel information (e.g., CSI, CQI) between the relay device and the dSTA device. It may also acquire, or generate, optimal power information (P2_opt) for the relay when it uses DF mode forwarding PPDUs to the dSTA. It may also obtain an amplifier gain (G) for the relay when it uses AF mode to forward PPDUs to the dSTA. In some embodiments, by using these parameters, the AP can determine an optimal power metric (Pl opt) for the AP forwarding PPDUs to the relay using aDF mode. For example, it may determine an optimal transmit power (Pl opt) of the AP when it transmits to the relay by considering the Hl information.

[0129] (Note that STAs may have associated relay forwarding maximum and minimum power for DF operations. They can be interpreted as the allowable power between devices, depending, for example, on the band (2.4, 5, 6 GHz). For example, in the case of a non-AP STA, the AP could provide this information, or the STA may recognize it considering coexistence. In some embodiments, an optimal power is the power that yields the best performance for given conditions. Another way to interpret optimal power is the smallest power that will nonetheless facilitate desired performance quality.)

[0130] In some embodiments, the AP uses these parameters to compare expected receiving performance functions for the dSTA. For example, a first function may correspond to the expected performance if AF mode is used and a second function may correspond to expected performance if DF mode is used. The first function may be based on Pl opt, G, Hl, and H2, and the second function may be based on P2_opt and H2. From here, the AP can select the relay mode by comparing the first and second functions. That is, if the first (AF) function is greater than the second (DF) function, then AF mode is selected, and if the second (DF) function is greater than the first (AF) function, then a DF mode is selected.

[0131] With reference to Figure 10, AF and DF mode parameters may be obtained in accordance with the following sequences. Initially, at 1001, channel information (e.g., Hl parameters) are obtained by the AP using feedback from the relay. NDPA and NDP frames are sent to the relay, which responds by sending back to the AP a beam forming report (e.g., a compressed BFR). Next, at 1002, the AP prepares the relay to obtain relay-dSTA parameters (e.g., H2, P2_opt, and G) from the relay. The AP transmits a variant trigger frame to the relay, which causes the relay to transmit an NFRP (NDP Feedback Report Poll) trigger frame. When the dSTA device receives the NFRP trigger frame from the relay, it transmits an NDP frame to the relay. The relay can calculate H2 using channel reciprocity on the NDP frame. The relay can then calculate P2_opt by using the derived H2 information. Finally, at 1003, the AP sends to the relay a variant trigger frame (e.g., a BFRP frame) to request not only the H2 information, but also, the P2_opt and G parameters. In this way, the relay can feedback these relay-dSTA parameters to the AP device.

[0132] With reference to Figure 11, these AF and DF mode parameters may be obtained in accordance with another frame transmission sequence. Initially, at 1101, the AP acquires Hl channel information from the relay as discussed with regard to Figure 10. At 1102, the AP next prepares the relay to feedback the H2, P2_opt, and G parameters back to it. The AP transmits avariant trigger frame to the relay, which causes the relay to transmit NDP an frame to the dSTA. This causes the dSTA to transmit a compressed beamforming report frame to the relay. Finally, at 1103, the AP transmits a variant trigger frame such as a BFRP frame to the relay device to receive from it H2, P2_opt, and G parameters. The variant trigger frame requests not only H2 but also P2_opt and G. By doing this, the relay can use frame feedback from the relay to receive relay-dSTA parameters, namely H2, P2_opt, and G.

[0133] Figures 12 and 13 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with some additional embodiments. With this approach, as compared with the approaches of Figures 10 and 11, it does not feedback the H2 parameters (e.g., channel information such as CSI and CQI between the relay and the dSTA) to the AP. It reduces the information that needs to be transmitted, which can reduce the required feedback size and thereby increase throughput. With this approach, the Hl (e.g., CSI / CQI channel parameters associated with the AP and the relay), P2_opt (optimal transmit power of DF forwarded PPDUs from relay to the dSTA), and G (usually a fixed, amplifier gain for AF mode forwarding from relay to dSTA). From these parameters, the AP can calculate Pl opt (an optimal DF mode transmit power of an the AP when transmitting to the relay) based on Hl. From here, the AP can use these parameters as input for a first function, an expected receiving performance of the dSTA in AF mode, and a second function, an expected receiving performance of the dSTA when the relay uses a DF mode. The first function (gl) may be based on Pl opt, G, and Hl, while the second function (g2) may be based on P2_Opt. The AP can then select the mode by comparing the two functions.

[0134] With reference to Figure 12, at 1201, the AP retrieves the Hl parameters through feedback as described above with reference to Figures 10 and 11. Next, at 1202, the AP prepares the relay device to feedback P2_opt and G parameters. The AP transmits a variant trigger frame to the relay, which causes the relay to transmit an NFRP trigger frame to the dSTA. When the dSTA receives the NFRP trigger frame from the relay, it transmits an NDP frame to the relay. The relay can then calculate H2 using channel reciprocity for the NDP frame. The relay can then also calculate P2_opt using the H2 information. Finally, at 1203, the calculated P2_opt information, as well as the gain (G) are fed back to the AP, which sends a variant trigger frame (e.g., BFRP frame) to the relay device to request the P2_opt and G information. In this way, a relay can feedback P2_opt and G.

[0135] With reference to Figure 13, another approach is depicted. At 1301, the AP obtains Hl information using feedback the relay as described above, next, at 1302, the AP prepares the relay to feedback P2_opt and G parameters. The AP transmits a variant trigger frame to therelay, which causes the relay to transmit an NDP frame to the dSTA. When the dSTA receives the NDP frame, it transmits back to the relay a compressed beamforming report frame to the relay. Finally, at 1303, P2_opt and G are fed back from the relay to the AP. With this example, the AP transmits to the relay a variant trigger frame (e.g., a BFRP frame) requesting the P2_opt and G information.

[0136] Figures 14 and 15 are diagrams showing transactions between an AP, a relay, and a dSTA for the AP to obtain AF and DF parameters in accordance with yet additional embodiments. With these approaches, the Hl information is not fed back from the relay. Instead, the AP calculates Hl using channel reciprocity after receiving from the relay an NDP frame.

[0137] With reference to Figure 14, at 1401, the AP acquires the channel information for Hl and H2. The AP transmits a variant trigger frame to the relay, which causes the relay to transmit an NDP frame to the AP and then to transmit an NDP frame to the dSTA. When the dSTA receives the NDP frame from the relay, it transmits a compressed beamforming report frame (e.g., with the H2 information) to the relay. The relay can then calculate P2_opt using the H2 information. When the AP receives the NDP frame from the relay, it can calculate Hl using channel reciprocity.

[0138] Finally, at 1402, the AP retrieves the parameters from the relay using feedback. It sends a variant trigger frame (e.g., BFRP frame) request not only to include the H2 information, but also, to include the P2_opt and G information as well. In this way, the relay can feedback H2, P2_opt, and G, which the AP can use to determine an expected DF performance for the relay-dSTA and compare it against an AF counterpart based on the Hl and Pl opt information.

[0139] With reference to Figure 15, at 1501, the AP acquires Hl and H2 information. The AP transmits a variant trigger frame to the relay, which causes the relay to transmit a variant NDP frame to the AP and also to the dSTA, concurrently. When the dSTA receives the variant NDP frame from the relay, it transmits a compressed beamforming report frame (e.g., H2) to the relay. The relay calculates P2_opt using the H2 information. Likewise, when the AP receives the variant NDP frame from the relay, it can calculate Hl using channel reciprocity.

[0140] At 1502, the AP transmits a variant trigger frame (e.g., BFRP frame) request not only to retrieve H2, but also, to request P2_opt and G as well. In this way, the relay can feedback H2, P2_opt and G.

[0141] Using any of the above approaches, the AP can compare expected receiving performances of the dSTA and select an appropriate forwarding mode, AF or DF.

[0142] Figure 16 is a diagram showing exemplary frame sequences between the AP, relay and dSTA when data is forwarded using an AF mode in accordance with some embodiments. At1601, the AP transmits an indication control frame to notify the relay to use an AF mode, and the relay responds by sending an ACK frame back to the AP. At 1402, the AP transmits PPDUs to the dSTA through the relay using the AF relay forwarded mode. In some embodiments, the AP may selected MCS parameters to include in the PPDUs by considering the Pl opt, Hl, and / or G information. The relay amplifies the received PPDUs by the amplification gain (G) and transmits it to the dSTA. Finally, at 1603, when the PPDU(s) have been forwarded, acknowledgement frames (ACK) are sent back as shown through the relay to the AP.

[0143] Figure 17 is a diagram showing exemplary frame sequences between the AP, relay and dSTA when data is forwarded using a DF mode in accordance with some embodiments. The sequences (1701, 1702, and 1703) are similar with those of the AF mode except that the relay is controlled to use a DF mode. The AP transmits PPDU(s) with selected MCS values based on the Pl opt and Hl information. The relay re-encodes PPDUs received from the AP and forwards them to the dSTA with selected MCS based on the P2_opt and H2 information.

[0144] Figure 18 is a diagram showing exemplary frame sequences between an AP, relay and a dSTA when data is forwarded using a DF mode in accordance with some other embodiments. This approach is the same as the approach of Figure 17 except the AP conveys to the relay the transmission power to be used for the DF mode forwarding. In some embodiments, this can be useful when optimal relay-dSTA power information (P2_opt) is not obtained but instead minimum (min) and / or maximum (max) DF power information is obtained.

[0145] Figure 19 is a diagram showing exemplary frame sequences between an AP, relay and a dSTA when data is forwarded using an AF mode in accordance with yet additional embodiments. At 1901, feedback parameters can be exchanged during a capability exchange event (e.g., using a probe response, beacon, etc.) or channel feedback as shown at 1901 in this example. However, instead of obtaining optimal P2 information, the AP obtains P2_min (relay’s minimum transmit power) and P2_max (relay’s maximum transmit power) information. It also may obtain relay amplifier gain (G) when the relay uses AF mode forwarding, Hl information, and H2 information. In some embodiments, using these parameters, the AP can calculate Pl opt. However, here, there may be three different situations when comparing expected performance.

[0146] A first (AF) performance function may be based on Pl opt, G, Hl, and H2. A second (DF) performance function may be based on P2_min and H2, and a third (DF) performance function may be based on P2_max and H2. The AP can decide the relay mode by comparing the functions. In the first scenario, the first function is greater than the two DF functions and thus, the AF mode would be selected. A second case is when both DF performance functions aregreater than the first (AF) performance function. In this case, the DF mode would be selected. But a third case arises when the first function performance is between the second and third function performances. With this latter situation, the relay mode may be decided according to the AP’s buffered packet type (e.g., low latency, high reliability, etc.). That is, if high reliability is most valued for the AP buffer packets, then a DF mode may be selected. On the other hand, if AP’s buffered packets are categorized as low-latency, then the AP may cause the relay to use an AF mode.

[0147] If an AP decides to cause the relay to forward data using a DF mode, the AP could find a power value that has better performance gain than if the AF mode were used. For example, when a relay uses the P2_min value for power when it has better performance than the AF mode, this may be preferred, e.g., to save relay battery power. Figure 18 shows a method for forwarding data with the AP being able to select DF power. The transmit power field can be used when a relay operates using a DF mode. This field has a meaningful field when a relay operates in a DF mode. When a relay operates in an AF mode, this field may be a reserved field. Alternatively, this field can be set as 0 to allow the relay to check additionally that a relay has indicated that it is to use an AF mode.

[0148] In some embodiments, performance comparisons for mode selection may be done using the power parameters, without the H2 information. An AP can acquire parameters using feedback or through a parameter exchange, e.g., during capabilities exchange (e.g., probe response, beacon, etc.) or through channel feedback. Obtained parameters may include P2_min, P2_max and G. It may also acquire Hl information. With these parameters, an AP can calculate Pl opt based on Hl. The AP can then use these parameters for performance functions. A first (AF mode) function may be based on Pl opt, G, and Hl, while a second (DF) function may be based on P2_min and / or P2_max, as described above. The AP can then select the relay forwarding mode based on the comparison of these two functions.

[0149] Figure 19 is a diagram showing transactions between an AP, a relay, and a dSTA for the AP to obtain parameters and select an AF mode in accordance with some embodiments. During an initial phase, at 1901, the AP acquires input parameters to compare expected receiving performance of a dSTA through the first and second functions described in the preceding paragraphs. In this example, the AP selects an AF operational mode. At 1902, the AP Indicates to the relay that AF mode should be used. At 1903, the relay receives PPDU(s) from the AP and forwards them to the dSTA using the AF forwarding mode.

[0150] Figure 20 is a diagram showing transactions between an AP, a relay, and a dSTA for the AP to obtain parameters and select an DF mode in accordance with some embodiments.Initially, at 2001, the AP acquires input parameters to compare expected receiving performance of the dSTA through the functions described in the preceding section. In this example, the AP selects the DF operation mode for the relay. At 2002, it indicates to the relay to employ the DF mode. At 2003, the AP prepares the relay to provide H2 parameter feedback for calculation of optimal transmit parameters (e.g., MCS, etc.) by using the H2 information. The AP transmits a variant trigger frame to the relay, which causes the relay to transmit an NFRP trigger frame. When the dSTA receives the NFRP trigger frame from the relay, it transmits an NDP frame to the relay. The relay can calculate H2 using channel reciprocity for the NDP frame. From here, the relay calculates optimal transmit parameters (e.g., P2_opt, etc.). The variant trigger frame has an indication not to forward the variant trigger frame to the dSTA to prevent forwarded unintentional PPDU(s) to the dSTA. At 2004, the relay re-encodes received PPDU(s) from the AP and forwards them to the dSTA.Examples

[0151] Illustrative examples of the technologies disclosed herein are provided below. An embodiment of the technologies may include any one or more, and any compatible combination of, the examples described below.

[0152] In some aspects, the techniques described herein relate to a method, including: in an access point (AP) device, wirelessly transmitting one or more control frames to a relay device to acquire relay transmission parameters for relay operations between the AP device and a destination station (dSTA) device through the relay device; comparing AF (amplify and forward) and DF (decode and forward) performance functions using the acquired relay transmission parameters; and selecting one of an AF and DF relay transmission modes based on the compared AF and DF performance functions.

[0153] In some aspects, the techniques described herein relate to a method, wherein the relay transmission parameters include a first set of channel information parameters associated with relay transmission between the relay device and the access point (AP) device.

[0154] In some aspects, the techniques described herein relate to a method, including: transmitting a first null data packet announcement (NDP A) frame to the relay device, transmitting a first null data packet (NDP) to the relay device, and receiving a first beam forming report (BFR) from the relay device.

[0155] In some aspects, the techniques described herein relate to a method, including: transmitting a first null data packet announcement (NDP A) frame to the relay device, receiving a second null data packet (NDP) from the relay device, and using channel reciprocity on the received second NDP to generate the first set of channel information parameters.

[0156] In some aspects, the techniques described herein relate to a method, wherein the relay transmission parameters include a second set of CSI (channel state information) parameters associated with relay transmission between the relay device and the dSTA device.

[0157] In some aspects, the techniques described herein relate to a method, including: causing the relay device to obtain the second set of channel information parameters from one or more frames from the dSTA device, and receiving the second set of channel information parameters from the relay device.

[0158] In some aspects, the techniques described herein relate to a method, wherein causing the relay device to obtain the second set of channel information parameters from one or more frames from the dSTA includes transmitting a first variant trigger frame to the relay device.

[0159] In some aspects, the techniques described herein relate to a method, wherein the first variant trigger frame is to cause the relay device to send to the dSTA device a third NDP frame to cause the dSTA device to send back to the relay a first beam forming report (BFR).

[0160] In some aspects, the techniques described herein relate to a method, wherein the first variant trigger frame causes the relay device to send a fourth NDP back to an access point (AP) device.

[0161] In some aspects, the techniques described herein relate to a method, wherein the third NDP to the dSTA device is a variant NDP frame that is sent to both the dSTA device and an AP device.

[0162] In some aspects, the techniques described herein relate to a method, wherein the first variant trigger frame is to cause the relay device to send a NFRP (NDP feedback report poll) frame to the dSTA device to cause it to send back to the relay device a fifth NDP frame, the relay device to obtain the second set of channel information parameters through the fifth NDP frame using channel reciprocity.

[0163] In some aspects, the techniques described herein relate to a method, including transmitting a first variant trigger frame to the relay device to receive back from it feedback including the second set of channel information parameters and a gain (G) for relay transmission using the AF mode.

[0164] In some aspects, the techniques described herein relate to a method, including determining a first power parameter using the first set of channel information parameters, the first power parameter associated with relay transmission between the relay device and the AP device.

[0165] In some aspects, the techniques described herein relate to a method, wherein the feedback includes a second power parameter associated with relay transmission between the relay device and the dSTA device using the DF mode.

[0166] In some aspects, the techniques described herein relate to a method, wherein the second power parameter includes min and max power parameters for relay transmissions between the relay device and the dSTA device.

[0167] In some aspects, the techniques described herein relate to a method, wherein the feedback includes a beam forming report.

[0168] In some aspects, the techniques described herein relate to a method, wherein the AF performance function is based on the first power parameter, the gain (G), and the first set of channel information parameters.

[0169] In some aspects, the techniques described herein relate to a method, wherein the DF performance function is based on the second power parameter.

[0170] In some aspects, the techniques described herein relate to a method, wherein the DF performance function is based on the second set of channel information parameters.

[0171] In some aspects, the techniques described herein relate to a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method 1-19.

[0172] In some aspects, the techniques described herein relate to a wireless apparatus, including: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method 1-19.

[0173] In some aspects, the techniques described herein relate to a method, including: in an access point (AP) device for relay transmissions between the AP device and a dSTA (destination STA) device through a relay device, acquiring first parameters for transmissions between the AP device and the relay device; acquiring second parameters for transmissions between the relay device and the dSTA device; comparing an expected performance of an AF (amplify and forward) mode with an expected performance of a DF (decode and forward) mode based on the acquired first and second-parameters; and selecting the AF or DF mode for relay transmission operation based on the compared expected performances.

[0174] In some aspects, the techniques described herein relate to a method, wherein selecting includes selecting the DF mode if reliability is prioritized over latency for data transmissions from the AP device.

[0175] In some aspects, the techniques described herein relate to a method, wherein the second parameters include minimum and maximum downlink power capabilities for DF transmission from the relay device to the dSTA device.

[0176] In some aspects, the techniques described herein relate to a method, wherein the second parameters include a second-parameter optimal power parameter for DF mode relay transmission from the relay device to the dSTA device.

[0177] In some aspects, the techniques described herein relate to a method, including: transmitting a variant trigger frame to the relay device to cause it to send an NFRP trigger frame to the dSTA device, wherein the relay is to receive from the dSTA device a first NDP frame in response to the NFRP trigger frame, wherein the relay device is to generate second-parameter channel information parameters using channel reciprocity for the first NDP frame and is to determine the second-parameter optimal power parameter from the second-parameter channel information parameters, and receiving the second-parameter optimal power parameter from the relay device.

[0178] In some aspects, the techniques described herein relate to a method, including: transmitting a variant trigger frame to the relay device to cause it to send a first NDP frame to the dSTA device, the relay device to receive from the dSTA device a beam forming report (BFR) in response to the first NDP frame, the relay device to acquire second-parameter channel information parameters from the BFR and to determine the second-parameter optimal power parameter from the acquired second-parameter channel information parameters, and receiving the second-parameter optimal power parameter from the relay device.

[0179] In some aspects, the techniques described herein relate to a method, wherein the first parameters include first-parameter channel information parameters.

[0180] In some aspects, the techniques described herein relate to a method, including: transmitting a null data packet announcement (NDP A) frame to the relay, receiving a second null data packet (NDP) from the relay, and using channel reciprocity on the received second NDP to generate the first-parameter channel information parameters.

[0181] In some aspects, the techniques described herein relate to a method, including determining a first-parameter optimal power parameter based on the first-parameter channel information parameters.

[0182] In some aspects, the techniques described herein relate to a method, wherein the expected performance for the DF mode is based on the second-parameter optimal power parameter.

[0183] In some aspects, the techniques described herein relate to a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method 22-31.

[0184] In some aspects, the techniques described herein relate to a wireless apparatus, including: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method 22-31.

[0185] In some aspects, the techniques described herein relate to a method, including: in a relay device, receiving a first control frame from an access point (AP) device; transmitting a second control frame to a destination station (dSTA) device in response to the first control frame; obtaining relay-dSTA channel information parameters from the dSTA device based on a response frame from the dSTA device; and providing to the AP device a relay-dSTA power parameter that is based on the relay-dSTA channel information parameters, the relay-dSTA power parameter being associated with downlink decode-forward (DF) transmissions from the relay device to the dSTA device.

[0186] In some aspects, the techniques described herein relate to a method, wherein obtaining relay-dSTA channel information parameters includes receiving the relay-dSTA channel information parameters from a beam forming report.

[0187] In some aspects, the techniques described herein relate to a method, wherein obtaining relay-dSTA channel information parameters includes generating the relay-dSTA channel information parameters using channel reciprocity for a first NDP frame received from the dSTA.

[0188] In some aspects, the techniques described herein relate to a method, including: receiving a first null data packet (NDP) from the AP device, and sending to the AP device an AP-relay beam forming report (BFR) that includes relay transmission parameters associated with amplify-forward (AF) downlink transmissions from the AP device to the relay device.

[0189] In some aspects, the techniques described herein relate to a method, including: receiving a first null data packet announcement (NDP A) frame from the AP device, and sending a null data packet (NDP) to the AP device suitable for the AP device to use channel reciprocity on the received NDP to generate channel information parameters associated with transmissions from the AP device to the relay device.

[0190] In some aspects, the techniques described herein relate to a non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method 34-38.

[0191] In some aspects, the techniques described herein relate to a wireless apparatus, including: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method 34-38.

[0192] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein may be or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one 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.

[0193] 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.

[0194] 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.

[0195] It should be bome 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.

[0196] The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general -purpose computer selectively activated or reconfigured by a computer program stored in the computer. For example, a computer system or other data processing system may carry out the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

[0197] 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.

[0198] In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Claims

CLAIMSWhat is claimed is:

1. A method, comprising: in an access point (AP) device, wirelessly transmitting one or more control frames to a relay device to acquire relay transmission parameters for relay operations between the AP device and a destination station (dSTA) device through the relay device; comparing AF (amplify and forward) and DF (decode and forward) performance functions using the acquired relay transmission parameters; and selecting one of an AF and DF relay transmission modes based on the compared AF and DF performance functions.

2. The method of claim 1, wherein the relay transmission parameters include a first set of channel information parameters associated with relay transmission between the relay device and the access point (AP) device.

3. The method of claim 2, including: transmitting a first null data packet announcement (NDPA) frame to the relay device, transmitting a first null data packet (NDP) frame to the relay device, and receiving a first beam forming report (BFR) from the relay device.

4. The method of claim 2, including: transmitting a first null data packet announcement (NDPA) frame to the relay device, receiving a second null data packet (NDP) frame from the relay device, and using channel reciprocity on the received second NDP frame to generate the first set of channel information parameters.

5. The method of any of claims 2-4, wherein the relay transmission parameters include a second set of channel information parameters associated with relay transmission between the relay device and the dSTA device.

6. The method of claim 5, including: causing the relay device to obtain the second set of channel information parameters from one or more frames from the dSTA device, and receiving the second set of channel information parameters from the relay device.

7. The method of claim 6, wherein causing the relay device to obtain the second set of channel information parameters from one or more frames from the dSTA includes transmitting a first variant trigger frame to the relay device.

8. The method of claim 7, wherein the first variant trigger frame is to cause the relay device to send to the dSTA device a third NDP frame to cause the dSTA device to send back to the relay a first beam forming report (BFR).

9. The method of claim 8, wherein the first variant trigger frame causes the relay device to send a fourth NDP frame back to an access point (AP) device.

10. The method of claim 8, wherein the third NDP frame to the dSTA device is a variant NDP frame that is sent to both the dSTA device and an AP device.

11. The method of claim 7, wherein the first variant trigger frame is to cause the relay device to send an NDP eliciting frame to the dSTA device to cause it to send back to the relay device a fifth NDP frame, the relay device to obtain the second set of channel information parameters through the fifth NDP frame using channel reciprocity.

12. The method of claim 11, wherein the NDP eliciting frame is an NFRP (NDP feedback report poll) frame.

13. The method of claim 5, including transmitting a first variant trigger frame to the relay device to receive back from it feedback including the second set of channel information parameters and a gain (G) for relay transmission using the AF mode.

14. The method of claim 13, including determining a first power parameter using the first set of channel information parameters, the first power parameter associated with relay transmission between the relay device and the AP device.

15. The method of claim 14, wherein the feedback includes a second power parameter associated with relay transmission between the relay device and the dSTA device using the DF mode.

16. The method of claim 15, wherein the second power parameter includes min and max power parameters for relay transmissions between the relay device and the dSTA device.

17. The method of any of claims 13-16, wherein the feedback includes a beam forming report.

18. The method of claim 15, wherein the AF performance function is based on the first power parameter, the gain (G), and the first set of channel information parameters.

19. The method of any of claims 15-18, wherein the DF performance function is based on the second power parameter.

20. The method of claim 19, wherein the DF performance function is based on the second set of channel information parameters.

21. A non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of claims 1-20.

22. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 1-20.

23. A method, comprising: in an access point (AP) device for relay transmissions between the AP device and a dSTA (destination STA) device through a relay device, acquiring first parameters for transmissions between the AP device and the relay device; acquiring second parameters for transmissions between the relay device and the dSTA device; comparing an expected performance of an AF (amplify and forward) mode with an expected performance of a DF (decode and forward) mode based on the acquired first and second-parameters; and selecting the AF or DF mode for relay transmission operation based on the compared expected performances.

24. The method of claim 23, wherein selecting includes selecting the DF mode if reliability is prioritized over latency for data transmissions from the AP device.

25. The method of claim 23, wherein the second parameters include minimum and maximum downlink power capabilities for DF transmission from the relay device to the dSTA device.

26. The method of claim 23, wherein the second parameters include a second-parameter optimal power parameter for DF mode relay transmission from the relay device to the dSTA device.

27. The method of claim 26, including: transmitting a variant trigger frame to the relay device to cause it to send an NFRP trigger frame to the dSTA device, wherein the relay is to receive from the dSTA device a first NDP frame in response to the NFRP trigger frame, wherein the relay device is to generate second-parameter channel information parameters using channel reciprocity for the first NDP frame and is to determine the second- parameter optimal power parameter from the second-parameter channel information parameters, and receiving the second-parameter optimal power parameter from the relay device.

28. The method of claim 26, including: transmitting a variant trigger frame to the relay device to cause it to send a first NDP frame to the dSTA device, the relay device to receive from the dSTA device a beam forming report (BFR) in response to the first NDP frame, the relay device to acquire second-parameter channel information parameters from the BFR and to determine the second-parameter optimal power parameter from the acquired second-parameter channel information parameters, and receiving the second-parameter optimal power parameter from the relay device.

29. The method of any of claims 23-28, wherein the first parameters include first-parameter channel information parameters.

30. The method of claim 29, including: transmitting a null data packet announcement (NDP A) frame to the relay, receiving a second null data packet (NDP) from the relay, and using channel reciprocity on the received second NDP to generate the first-parameter channel information parameters.

31. The method of claim 30, including determining a first-parameter optimal power parameter based on the first-parameter channel information parameters.

32. The method of any of claims 23-31, wherein the expected performance for the DF mode is based on the second-parameter optimal power parameter.

33. A non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of claims 23-32.

34. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 23-32.

35. A method, comprising: in a relay device, receiving a first control frame from an access point (AP) device; transmitting a second control frame to a destination station (dSTA) device in response to the first control frame; obtaining relay-dSTA channel information parameters from the dSTA device based on a response frame from the dSTA device; and providing to the AP device a relay-dSTA power parameter that is based on the relay - dSTA channel information parameters, the relay-dSTA power parameter being associated with downlink decode-forward (DF) transmissions from the relay device to the dSTA device.

36. The method of claim 35, wherein obtaining relay-dSTA channel information parameters includes receiving the relay-dSTA channel information parameters from a beam forming report.

37. The method of claim 35, wherein obtaining relay-dSTA channel information parameters includes generating the relay-dSTA channel information parameters using channel reciprocity for a first NDP frame received from the dSTA.

38. The method of any of claims 35-37, including: receiving a first null data packet (NDP) from the AP device, and sending to the AP device an AP-relay beam forming report (BFR) that includes relay transmission parameters associated with amplify -forward (AF) downlink transmissions from the AP device to the relay device.

39. The method of any of claims 35-37, including: receiving a first null data packet announcement (NDP A) frame from the AP device, and sending a null data packet (NDP) to the AP device suitable for the AP device to use channel reciprocity on the received NDP to generate channel information parameters associated with transmissions from the AP device to the relay device.

40. A non-transitory machine readable medium having instructions that when executed by a wireless device cause the wireless device to perform a method as recited in any of claims 35-39.

41. A wireless apparatus, comprising: a baseband processor; a radio frequency (RF) transceiver coupled to the baseband processor; and a storage device coupled to the baseband processor, the storage device including instructions that when executed by the baseband processor cause it to perform a method as recited in any of claims 35-39.

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