Physical layer preamble design

Abstract

The present disclosure provides methods, devices and systems for generating packet preambles. Some implementations more specifically relate to preamble designs that support data throughput gains that can be realized according to the IEEE 802.11be amendments and future generations of IEEE 802.11 standards. In other examples, the preamble design of this implementation can allow more reliable packet detection, more accurate channel estimation and more robust decoding of signal field (SIG) symbols. Additionally or alternatively, compared with the preamble design that follows the existing version of the IEEE 802.11 standard, the preamble design of the present disclosure can be realized using different lengths, modulation schemes or transmission powers.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 027,337, filed on May 19, 2020, entitled “PHYSICAL LAYER PREAMBLEDESIGN,” and U.S. Provisional Patent Application No. 63 / 033,810, filed on June 2, 2020, entitled “PHYSICAL LAYER PREAMBLE FOR EXTENDED RANGE (ER) PACKET FORMAT,” and U.S. Non-Provisional Application No. 17 / 323,563, filed on May 18, 2021, entitled “PHYSICAL LAYER PREAMBLE DESIGN,” all of which are assigned to the assignee of this application. The disclosures of all prior applications are considered part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to physical layer preambles and signaling for wireless transmissions.

[0004] Related technical description

[0005] A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless communication medium for use by several client devices, also referred to as stations (STAs). The basic building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is a basic service set (BSS) managed by an AP. Each BSS is identified by a basic service set identifier (BSSID) announced by the AP. The AP periodically broadcasts beacon frames to enable any STA within the wireless range of the AP to establish or maintain a communication link with the WLAN.

[0006] New WLAN communication protocols are being developed to implement enhanced WLAN communication features. As the new WLAN communication protocols implement enhanced features, new preamble designs are required to support signaling associated with the new features and packet formats. Additionally, new preamble designs may be required to ensure that such signaling can be reliably communicated over an extended range, such as, for example, in an outdoor environment.

[0007] Overview

[0008] The systems, methods, and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0009] One innovative aspect of the subject matter described in the present disclosure may be implemented as a wireless communication method. The method may be performed by a wireless communication device and may include: receiving a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0; detecting one or more modulation schemes associated with the U-SIG; and determining a format of the packet based on the detected modulation scheme associated with the U-SIG. In some implementations, the detection of the one or more modulation schemes may include determining that a first symbol of the U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme; and determining that a second symbol of the U-SIG is modulated according to a quadrature BPSK (QBPSK) modulation scheme.

[0010] In some implementations, determining the format of the packet may include: determining that the U-SIG further includes at least a third symbol and a fourth symbol based on determining that the second symbol of the U-SIG is modulated according to the QBPSK modulation scheme, wherein the first symbol of the U-SIG carries the same decoded bits as the second symbol of the U-SIG, and the third symbol of the U-SIG carries the same decoded bits as the fourth symbol of the U-SIG. In some aspects, each of the first symbol and the second symbol may be transmitted on a plurality of subcarriers, wherein the decoded bits of the first symbol are modulated on the plurality of subcarriers in a different order than the decoded bits of the second symbol. In some aspects, each of the third symbol and the fourth symbol may be transmitted on a plurality of subcarriers, wherein the decoded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the decoded bits of the fourth symbol.

[0011] In some implementations, the method may further include: determining timing of a non-legacy short training field (STF) of the physical layer preamble relative to a U-SIG based on the format of the packet; and initiating automatic gain control (AGC) based on the timing of the non-legacy STF. In some aspects, a packet may include one or more padding symbols between the U-SIG and the non-legacy STF.

[0012] In some implementations, the determination of the format of the packet may include determining that the packet follows a non-legacy extended range (ER) packet format based on a value of a version identifier subfield of the U-SIG and a determination that the second symbol of the U-SIG is modulated according to the QBPSK modulation scheme. In some aspects, the preamble may further include a non-legacy signal field immediately following the U-SIG, wherein the non-legacy signal field includes a single user field and one or more overflow bits from the U-SIG. In some aspects, the U-SIG may include a user field that carries user-specific information for a single user, wherein the preamble further includes a non-legacy STF immediately following the U-SIG.

[0013] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a wireless communication device. In some implementations, the wireless communication device may include at least one modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. In some implementations, execution of the processor-readable code by the at least one processor causes the wireless communication device to perform operations, including: receiving a packet including a physical layer preamble, the physical layer preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0; detecting one or more modulation schemes associated with the U-SIG; and determining the format of the packet based on the detected modulation scheme associated with the U-SIG. In some implementations, detecting one or more modulation schemes may include determining that a first symbol of the U-SIG is modulated according to a BPSK modulation scheme; and determining that a second symbol of the U-SIG is modulated according to a QBPSK modulation scheme.

[0014] Another innovative aspect of the subject matter described in the present disclosure may be implemented as a wireless communication method. The method may be performed by a wireless communication device and may include: generating a packet including a physical layer preamble, the physical layer preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0; modulating a first symbol of the U-SIG according to a BPSK modulation scheme; modulating a second symbol of the U-SIG according to a QBPSK modulation scheme; and transmitting the packet over a wireless channel.

[0015] In some implementations, the U-SIG may further include at least a third symbol and a fourth symbol, wherein the first symbol of the U-SIG carries the same decoded bits as the second symbol of the U-SIG, and the third symbol of the U-SIG carries the same decoded bits as the fourth symbol of the U-SIG. In some aspects, the decoded bits of the first symbol may be modulated on multiple subcarriers in a different order than the decoded bits of the second symbol. In some aspects, the decoded bits of the third symbol may be modulated on multiple subcarriers in a different order than the decoded bits of the fourth symbol. In some aspects, the packet may include one or more padding symbols between the U-SIG and the non-legacy STF of the physical layer preamble.

[0016] In some implementations, the packet may follow a non-legacy ER packet format having a bandwidth equal to 20 MHz. In some aspects, the preamble may further include a non-legacy signal field immediately following the U-SIG, wherein the non-legacy signal field includes a single user field and one or more overflow bits from the U-SIG. In some aspects, the U-SIG may further include a user field carrying user-specific information for a single user, wherein the preamble further includes a non-legacy STF immediately following the U-SIG.

[0017] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a wireless communication device. In some implementations, the wireless communication device may include at least one modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. In some implementations, execution of the processor-readable code by the at least one processor causes the wireless communication device to perform operations, including: generating a packet including a physical layer preamble, the physical layer preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0; modulating a first symbol of the U-SIG according to a BPSK modulation scheme; modulating a second symbol of the U-SIG according to a QBPSK modulation scheme; and transmitting the packet on a wireless channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Details of one or more implementations of the subject matter described in the present disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative sizes of the following drawings may not be drawn to scale.

[0020] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0021] Figure 2A Example protocol data units (PDUs) that may be used for communications between an access point (AP) and one or more wireless stations (STAs) are shown.

[0022] Figure 2B Shows Figure 2A Example fields in a PDU.

[0023] Figure 3 An example physical layer (PHY) protocol data unit (PPDU) that may be used for communications between an AP and one or more STAs is shown.

[0024] Figure 4 A block diagram of an example wireless communication device is shown.

[0025] Figure 5A A block diagram of an example AP is shown.

[0026] Figure 5B A block diagram of an example STA is shown.

[0027] Figure 6 An example PPDU is shown that may be used for communication between an AP and several STAs according to some implementations.

[0028] Fig. 7A An example frame structure for a trigger-based (TB) PPDU is shown according to some implementations.

[0029] Figure 7B An example frame structure for a multi-user (MU) PPDU is shown in accordance with some implementations.

[0030] Figure 8 An example frame structure of a non-legacy PPDU allocated across multiple subchannels of a wireless channel according to some implementations is shown.

[0031] Fig.9A An example PHY preamble for a non-legacy PPDU is shown in accordance with some implementations.

[0032] Fig. 9B Another example PHY preamble for a non-legacy PPDU is shown in accordance with some implementations.

[0033] Fig. 10A An example PHY preamble for a non-legacy PPDU is shown in accordance with some implementations.

[0034] Fig. 10B Another example PHY preamble for a non-legacy PPDU is shown in accordance with some implementations.

[0035] Fig.11 An example extended range (ER) single user (SU) PPDU is shown according to some implementations.

[0036] Fig.12 An example frame structure for an ER SU PPDU is shown according to some implementations.

[0037] Fig.13A A flow chart illustrating an example process for supporting wireless communications with a PHY preamble design according to some implementations is shown.

[0038] Fig. 13B A flow chart illustrating an example process for supporting wireless communications with a PHY preamble design according to some other implementations is shown.

[0039] Fig. 13C A flow chart illustrating an example process for supporting wireless communications with a PHY preamble design according to some other implementations is shown.

[0040] Fig.14 A flow chart illustrating an example process for supporting wireless communications with a PHY preamble design according to some other implementations is shown.

[0041] Fig.15 A flow chart illustrating an example process for supporting wireless communications that increase transmit power of a training field of a PHY preamble in accordance with some implementations is shown.

[0042] Fig.16 A flow chart illustrating an example process for supporting wireless communications that increase transmit power of a training field of a PHY preamble according to some other implementations is shown.

[0043] Fig.17 A flow chart illustrating an example process for supporting wireless communications that increase transmit power of a training field of a PHY preamble according to some other implementations is shown.

[0044] Fig.18 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0045] Fig.19 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0046] Like reference numbers and designations in the various drawings indicate like elements.

[0047] Detailed Description

[0048] The following description is directed to certain implementations in order to describe the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in a manner that is capable of being implemented in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth SIG standard, or the like as defined by the Bluetooth Special Interest Group (SIG). The described implementations may be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals in accordance with one or more of the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards, or the like released by the Third Generation Partnership Project (3GPP). The described implementations may be implemented in any device, system, or network capable of transmitting and receiving RF signals in accordance with one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), single user (SU) multiple input multiple output (MIMO), and multi-user (MU) MIMO. The described implementations may also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN), a wireless local area network (WLAN), a wireless wide area network (WWAN), or an Internet of Things (IOT) network.

[0049] New WLAN communication protocols are being developed to implement enhanced WLAN communication features. Because the new WLAN communication protocols implement enhanced features, new preamble designs are needed to support signaling related to the new features and packet formats. Additionally, new preamble designs may be needed to ensure that such signaling can be reliably communicated over an extended range, such as, for example, in an outdoor environment. Signaling refers to a control field or information that can be used by a wireless communication device to interpret another field or portion of a packet. Such information can be encoded in the physical layer (PHY) preamble of the packet. However, decoding and processing the signaling information consumes time and resources, which may delay the processing of other information carried in the packet.

[0050] In summary, various aspects relate to signaling included in a PHY preamble supporting a new wireless communication protocol, and more specifically, to a preamble design supporting extended range communications or data throughput gains achievable according to the 1EEE 802.11be revision of the IEEE 802.11 standard and future generations. In some aspects, compared with the preamble design following the existing version of the IEEE 802.11 standard, the preamble design of the present disclosure can be implemented using different lengths, modulation schemes, or frame structures. For example, information carried in one or more fields of the PHY preamble can be repeated (in time) to provide an increased signaling gain at a receiving device. In some implementations, such information can be carried in a universal signal field (U-SIG) of the PHY preamble. In some other implementations, such information can be carried in a non-legacy signal field of the PHY preamble. As used herein, the term "non-legacy" can refer to packet formats and communication protocols following the IEEE 802.11be revision of the 1EEE 802.11 standard and future generations.

[0051] Specific implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. The preamble design of this implementation may allow for more reliable packet detection, more accurate channel estimation, and more robust decoding of signaling information in non-legacy packets. Various aspects of this disclosure may also enable early detection of various content (or lack of such content) in the PHY preamble, and provide more time for the receiving device to process such content, by adjusting the length, modulation scheme, or frame structure associated with the physical layer preamble.

[0052] Figure 1 A block diagram of an example wireless communication network 100 is shown. According to some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN) such as a Wi-Fi network (and will be referred to as WLAN 100 hereinafter). For example, the WLAN 100 may be a network that implements at least one of the IEEE 802.11 family of wireless communication protocol standards, such as the standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. The WLAN 100 may include numerous wireless communication devices, such as an access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP 102 is shown, the WLAN network 100 may also include a plurality of APs 102.

[0053] Each STA 104 may also be referred to as a mobile station (MS), a mobile device, a mobile handset, a wireless handset, an access terminal (AT), a user equipment (UE), a subscriber station (SS), or a subscriber unit, among other possibilities. STA 104 may represent a variety of devices, such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo equipment, remote control devices (“remote controls”), printers, kitchen or other home appliances, key fobs (e.g., for passive keyless entry and start (PKES) systems), and other possibilities.

[0054] A single AP 102 and the associated set of STAs 104 may be referred to as a basic service set (BSS), which is managed by the corresponding AP 102 . Figure 1 Additionally shown is an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. The BSS may be identified to users by a service set identifier (SSID) and may also be identified to other devices by a basic service set identifier (BSSID), which may be a media access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame (“beacon”) including the BSSID to enable any STA 104 within the wireless range of the AP 102 to “associate” or reassociate with the AP 102 to establish or maintain a corresponding communication link 108 (hereinafter also referred to as a “Wi-Fi link”) with the AP 102. For example, the beacon may include an identification of a primary channel used by the corresponding AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to external networks to various STAs 104 in the WLAN via corresponding communication links 108 .

[0055] The AP 102 and the STA 104 may function and communicate (via corresponding communication links 108) in accordance with the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 specification or its amendments, including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. These standards define WLAN radio and baseband protocols for the PHY and media access control (MAC) layers. The AP 102 and the STA 104 transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") to and from each other in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs). The AP 102 and STA 104 in the WLAN 100 may transmit PPDUs on an unlicensed spectrum, which may be a portion of a spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5 GHz band, the 60 GHz band, the 3.6 GHz band, and the 700 MHz band. Some implementations of the AP 102 and STA 104 described herein may also communicate in other frequency bands, such as the 6 GHz band, that may support both licensed and unlicensed communications. The AP 102 and STA 104 may also be configured to communicate on other frequency bands, such as shared licensed frequency bands, where multiple operators may have licenses to operate in one or more of the same or overlapping frequency bands.

[0056] Figure 2A An example protocol data unit (PDU) 200 that may be used for wireless communication between an AP 102 and one or more STAs 104 is shown. For example, the PDU 200 may be configured as a PPDU. As shown, the PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, the preamble 202 may include a legacy portion that itself includes a legacy short training field (L-STF) 206 that may consist of two BPSK symbols, a legacy long training field (L-LTF) 208 that may consist of two BPSK symbols, and a legacy signal field (L-SIG) 210 that may consist of two BPSK symbols. The legacy portion of the preamble 202 may be configured in accordance with the IEEE 802.11a wireless communication protocol standard. The preamble 202 may also include a non-legacy portion including one or more non-legacy fields 212 that comply with, for example, an IEEE wireless communication protocol such as IEEE 802.11ac, 802.11ax, 802.11be, or a later wireless communication protocol.

[0057] L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and can also perform initial estimation of the wireless channel. L-SIG 210 generally enables the receiving device to determine the duration of the PDU and use the determined duration to avoid transmitting on the PDU. For example, L-STF 206, L-LTF 208 and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. Payload 204 can be modulated according to a BPSK modulation scheme, an orthogonal BPSK (Q-BPSK) modulation scheme, an orthogonal amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. Payload 204 may include a PSDU including a data field (DATA) 214, which in turn may carry, for example, a higher layer data in the form of a media access control (MAC) protocol data unit (MPDU) or an aggregated MPDU (A-MPDU).

[0058] Figure 2B Shows Figure 2A 2. An example L-SIG 210 in a PDU 200 of FIG. 210 includes a data rate field 222, reserved bits 224, a length field 226, parity bits 228, and a tail field 230. The data rate field 222 indicates the data rate (note that the data rate indicated in the data rate field 212 may not be the actual data rate of the data carried in the payload 204). The length field 226 indicates the packet length, for example, in symbols or bytes. The parity bits 228 may be used to detect bit errors. The tail field 230 includes tail bits, which may be used by a receiving device to terminate the operation of a decoder (e.g., a Viterbi decoder). The receiving device may use the data rate and length indicated in the data rate field 222 and the length field 226 to determine the packet duration, for example, in microseconds (μs) or other time units.

[0059] Figure 3An example PPDU 300 is shown that may be used for communication between an AP 102 and one or more STAs 104. As described above, each PPDU 300 includes a PHY preamble 302 and a PSDU 304. Each PSDU 304 may represent (or "carry") one or more MAC protocol data units (MPDUs) 316. For example, each PSDU 304 may carry an aggregated MPDU (A-MPDU) 306 that includes an aggregation of multiple A-MPDU subframes 308. Each A-MPDU subframe 306 may include an MPDU frame 310 that includes a MAC delimiter 312 and a MAC header 314 preceding an accompanying MPDU 316 that includes a data portion ("payload" or "frame body") of the MPDU frame 310. Each MPDU frame 310 may also include a frame check sequence (FCS) field 318 for error detection (e.g., the FCS field may include a cyclic redundancy check (CRC)) and padding bits 320. The MPDU 316 may carry one or more MAC service data units (MSDUs) 330. For example, the MPDU 316 may carry an aggregated MSDU (A-MSDU) 322, which includes multiple A-MSDU subframes 324. Each A-MSDU subframe 324 contains a corresponding MSDU 330, which is preceded by a subframe header 328 and, in some cases, followed by padding bits 332.

[0060] Referring back to the MPDU frame 310, the MAC delimiter 312 may be used as a marker for the start of an associated MPDU 316 and indicates the length of the associated MPDU 316. The MAC header 314 may include a plurality of fields containing information defining or indicating characteristics or attributes of the data encapsulated within the frame body 316. The MAC header 314 includes a duration field indicating a duration from the end of the PPDU to at least the end of an acknowledgment (ACK) or block ACK (BA) of the PPDU to be transmitted by the receiving wireless communication device. The use of the duration field is used to reserve the wireless medium for the indicated duration and enable the receiving device to establish its network allocation vector (NAV). The MAC header 314 also includes one or more fields indicating the address of the data encapsulated within the frame body 316. For example, the MAC header 314 may include a combination of a source address, a transmitter address, a receiver address, or a destination address. The MAC header 314 may further include a frame control field containing control information. The frame control field may specify a frame type, such as a data frame, a control frame, or a management frame.

[0061] Figure 4 4 shows a block diagram of an example wireless communication device 400. In some implementations, the wireless communication device 400 may be a STA (such as a Figure 1In some implementations, the wireless communication device 400 may be an example of a device in an AP (such as one of the STAs 104 described above). Figure 1 The wireless communication device 400 is an example of a device in the described AP 102. The wireless communication device 400 is capable of transmitting (or outputting for transmission) and receiving wireless communications (e.g., in the form of wireless packets). For example, the wireless communication device can be configured to: transmit and receive packets in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs) and media access control (MAC) protocol data units (MPDUs) that comply with the IEEE 802.11 wireless communication protocol standards (such as the standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0062] The wireless communication device 400 may be or may include a chip, system on chip (SoC), chipset, package, or device including one or more modems 402 (e.g., Wi-Fi (IEEE 802.11 compliant) modems). In some implementations, one or more modems 402 (collectively, “modems 402”) additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compatible modem). In some implementations, the wireless communication device 400 also includes one or more radios 404 (collectively, “radios 404”). In some implementations, the wireless communication device 406 further includes one or more processors, processing blocks, or processing elements 406 (collectively, “processors 406”) and one or more memory blocks or elements 408 (collectively, “memory 408”).

[0063] The modem 402 may include an intelligent hardware block or device, such as, for example, an application specific integrated circuit (ASIC) or the like. The modem 402 is generally configured to implement the PHY layer. For example, the modem 402 is configured to modulate packets and output the modulated packets to the radio 404 for transmission on the wireless medium. Similarly, the modem 402 is configured to obtain modulated packets received by the radio 404 and demodulate the packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 402 may further include a digital signal processing (DSP) circuit system, an automatic gain control (AGC), an encoder, a decoder, a multiplexer, and a demultiplexer. For example, when in the transmission mode, the data obtained from the processor 406 is provided to a decoder, which encodes the data to provide coded bits. The coded bits are then mapped to points in the modulation constellation (using the selected MCS) to provide modulated symbols. Subsequently, the modulated symbols may be mapped to a number (N SS ) spatial streams or several (N STS The modulated symbols in the corresponding spatial stream or space-time stream may then be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and then provided to the DSP circuitry for Tx windowing and filtering. The digital signal may then be provided to a digital-to-analog converter (DAC). The resulting analog signal may then be provided to an upconverter and ultimately to the radio 404. In an implementation involving beamforming, the modulated symbols in the corresponding spatial stream may be precoded via a steering matrix before being provided to the IFFT block.

[0064] When in receive mode, a digital signal received from the radio 404 is provided to a DSP circuit system that is configured to acquire the received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offset. The DSP circuit system is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. Subsequently, the output of the DSP circuit system may be fed to an AGC that is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine an appropriate gain. The output of the DSP circuit system is also coupled to a demodulator that is configured to extract modulated symbols from the signal and, for example, calculate a log-likelihood ratio (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder that may be configured to process the LLRs to provide decoded bits. Subsequently, the decoded bits from all spatial streams are fed to a demultiplexer for demultiplexing. The demultiplexed bits may then be descrambled and provided to the MAC layer (processor 406) for processing, evaluation, or interpretation.

[0065] The radio 404 generally includes at least one radio frequency (RF) transmitter (or "transmitter chain") and at least one RF receiver (or "receiver chain"), which may be combined into one or more transceivers. For example, the RF transmitter and receiver may include various DSP circuit systems, including at least one power amplifier (PA) and at least one low noise amplifier (LNA), respectively. The RF transmitter and receiver may in turn be coupled to one or more antennas. For example, in some implementations, the wireless communication device 400 may include or be coupled to multiple transmit antennas (each having a corresponding transmit chain) and multiple receive antennas (each having a corresponding receive chain). The codewords output from the modem 402 are provided to the radio 404, which then transmits the codewords via the coupled antenna. Similarly, the codewords received via the antenna are obtained by the radio 404, which then provides the codewords to the modem 402.

[0066] The processor 406 may include an intelligent hardware block or device designed to perform the functions described herein, such as, for example, a processing core, a processing block, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD) (such as a field programmable gate array (FPGA)), discrete gate or transistor logic, discrete hardware components, or any combination thereof. The processor 406 processes information received through the radio 404 and the modem 402, and processes information to be output by the modem 402 and the radio 404 for transmission over a wireless medium. For example, the processor 406 may implement a control plane and a MAC layer, which is configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate coding and decoding of frames, spatial multiplexing, space-time block coding (STBC), beamforming, and OFDMA resource allocation, and other operations or techniques. In some implementations, the processor 406 may generally control the modem 402 to cause the modem to perform the various operations described above.

[0067] The memory 408 may include a tangible storage medium, such as a random access memory (RAM) or a read-only memory (ROM) or a combination thereof. The memory 408 may also store non-transient processor or computer executable software (SW) code containing instructions that, when executed by the processor 406, cause the processor to perform various operations for wireless communication described herein, including generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, the various functions of the various components disclosed herein or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein may be implemented as one or more modules of one or more computer programs.

[0068] Figure 5A 5 shows a block diagram of an example AP 502. For example, the AP 502 may be a reference Figure 1 An example implementation of AP 102 is described. AP 502 includes a wireless communication device (WCD) 510 (although AP 502 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 510 may be a wireless communication device (WCD) 510. Figure 4 An example implementation of the wireless communication device 400 described. The AP 502 also includes a plurality of antennas 520 coupled to the wireless communication device 510 to transmit and receive wireless communications. In some implementations, the AP 502 additionally includes an application processor 530 coupled to the wireless communication device 510, and a memory 540 coupled to the application processor 530. The AP 502 further includes at least one external network interface 550, which enables the AP 502 to communicate with a core network or a backhaul network to obtain access to an external network including the Internet. For example, the external network interface 550 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components in the aforementioned components may communicate directly or indirectly with other components in these components on at least one bus. The AP 502 further includes a housing that encloses the wireless communication device 510, the application processor 530, the memory 540, and encloses at least a portion of the antenna 520 and the external network interface 550.

[0069] Figure 5B 5 shows a block diagram of an example STA 504. For example, STA 504 may be a reference Figure 1 104. STA 504 includes a wireless communication device 515 (although STA 504 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 515 may be a wireless communication device. Figure 4An example implementation of the wireless communication device 400 described. The STA 504 also includes one or more antennas 525 coupled to the wireless communication device 515 to transmit and receive wireless communications. The STA 504 additionally includes an application processor 535 coupled to the wireless communication device 515, and a memory 545 coupled to the application processor 535. In some implementations, the STA 504 further includes a user interface (UI) 555 (such as a touch screen or keyboard) and a display 565, which can be integrated with the UI 555 to form a touch screen display. In some implementations, the STA 504 may further include one or more sensors 575 (such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors, for example). Components in the aforementioned components can communicate directly or indirectly with other components in these components on at least one bus. The STA 504 further includes a housing that encloses the wireless communication device 515, the application processor 535, the memory 545, and at least portions of the antenna 525, the UI 555, and the display 565.

[0070] Figure 6 An example PPDU 600 that may be used for wireless communication between an AP and a number of STAs according to some implementations is shown. The PPDU 600 may be used for transmission to a single user, MU-OFDMA, or non-OFDMA MU-MIMO transmission. The PPDU 600 includes a PHY preamble that includes a first portion 602 and a second portion 604. The PPDU 600 may further include a PHY payload 606 (e.g., in the form of a PSDU including a data field 626) following the preamble.

[0071] The first portion 602 includes an L-STF 608, an L-LTF 610, and an L-SIG 612. The second portion 604 of the preamble and the data field 626 may be formatted as a non-legacy or extremely high throughput (EHT) WLAN preamble and frame, respectively, according to the IEEE 802.11be amendment to the IEEE 802.11 wireless communication protocol standard, or may be formatted as a preamble and frame, respectively, that conform to any later (post-HE) version of a new wireless communication protocol (conforming to future IEEE 802.11 wireless communication protocol standards or other standards). In some implementations, the PPDU 600 may be logically divided into an EHT pre-modulation portion 650 (including PPDU fields 608-618) and an EHT modulation portion 660 (including PPDU fields 622-626).

[0072] The second portion 604 of the preamble includes a repeated legacy signal field (RL-SIG) 614 and a plurality of wireless communication protocol version related signal fields following the RL-SIG 614. For example, in some aspects, the second portion may include a universal signal field (U-SIG) 616 and an EHT signal field (EHT-SIG) 618. The second portion 604 further includes an EHT short training field (EHT-STF) 622 and a plurality of EHT long training fields (EHT-LTF) 624.

[0073] In some implementations, the U-SIG 616 may include one or more version-independent fields 632 and one or more version-dependent fields 634. The information in the version-independent field 632 may include, for example, a version identifier (starting with 1EEE 802.11be amendment and later amendments) and channel occupancy and coexistence information (such as PPDU bandwidth). The version-dependent field 634 may include a format information field for interpreting other fields of the U-SIG 616 and the EHT-SIG 618. In some implementations, the version-dependent field 634 may include at least a PPDU type and compression mode field 636. The PPDU type and compression mode field 636 may indicate a general PPDU format and compression mode for the PPDU 600. Example suitable PPDU formats include a triggered-based (TB) PPDU format, a MU PPDU format for DL ​​OFDMA transmission, a MU PPDU format for transmission to a single user or for transmission of a null data packet (NDP), and a MU PPDU format for DL ​​non-OFDMA MU-MIMO transmission.

[0074] In some implementations, the EHT-SIG 618 may include a common field 642 and a user-specific field 644. The common field 642 includes one or more bits or fields 646 overflowed from the U-SIG 616 and RU allocation information 648 for the intended recipients of the PPDU 600. The user-specific field 644 may include one or more user fields carrying per-user information for one or more intended recipients of the PPDU 600. In some implementations, the RU allocation information 648 may be replaced by the number of non-OFDMA users field in the MU PPDU for DL ​​non-OFDMA transmissions or transmissions to a single user. Still further, in some implementations, the EHT-SIG 618 may not be present in the TB PPDU format.

[0075] As previously described, in IEEE 802.11be and future generations, new fields may be used to carry signaling information. For example, new fields and signaling information may be included in U-SIG 616. In addition, new fields and signaling information may be included in EHT-SIG 618 (or may overflow from U-SIG 616 to EHT-SIG 618). In some implementations, U-SIG 616 may include signaling about the type or format of additional signal fields (such as EHT-SIG 618) after U-SIG 616. The AP may use EHT-SIG 618 to identify that the AP has scheduled UL or DL ​​resources and notify one or more STAs 104. The EHT-SIG 618 may be decoded by each compatible STA 104 served by the AP 102. The EHT-SIG 618 may generally be used by the receiving device to interpret the bits in the data field 626. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding RU in the associated data field 626.

[0076] Fig. 7A FIG. 7 shows an example frame structure for a TB PPDU 700 according to some implementations. In some implementations, the TB PPDU 700 may be Figure 6 For simplicity, Fig. 7A Only the EHT pre-modulation portion of the TB PPDU 700 (corresponding to portion 650 of the PPDU 600) is shown. The TB PPDU 700 includes an L-STF 701, an L-LTF 702, an L-SIG 703, an RL-SIG 704, and a U-SIG 705, which may correspond to the L-STF 608, L-LTF 610, L-SIG 612, RL-SIG 614, and U-SIG 616 of the PPDU 600, respectively. In the example TB PPDU format, the TB PPDU 700 may not include the EHT-SIG. Referring to, for example Figure 6 , the TB PPDU 700 may not include any U-SIG overflow 646, RU allocation information 648, or other user-specific information (such as provided in the user-specific field 644).

[0077] Figure 7B An example frame structure for a MU PPDU 720 according to some implementations is shown. In some implementations, the MU PPDU 720 may be Figure 6 For simplicity, Figure 7B6. Only the pre-EHT modulation portion of the MU PPDU 720 (corresponding to the portion 650 of the PPDU 600) is shown in FIG. 6. The MU PPDU 720 includes an L-STF 721, an L-LTF 722, an L-SIG 723, an RL-SIG 724, an U-SIG 725, and an EHT-SIG 726, which may correspond to the L-STF 608, the L-LTF 610, the L-SIG 612, the RL-SIG 614, the U-SIG 616, and the EHT-SIG 616 of the PPDU 600, respectively. In the example MU PPDU format, the EHT-SIG 726 may include a common field 727 and a user-specific field 728. For example, referring to FIG. Figure 6 The common fields 642 may further include U-SIG overflow 646 and RU allocation information 648. The user-specific fields 728 may include per-user information for one or more intended recipients of the MUPPDU 720.

[0078] In some implementations, the MU PPDU format may be used for transmission to a single user or non-OFDMA MU-MIMO transmission. More specifically, transmission to a single user (when the PPDU type and compression mode fields of the U-SIG are set to 1) and non-OFDMA MU-MIMO transmission (when the PPDU type and compression mode fields of the U-SIG are set to 2) may be achieved by compressing (reducing or eliminating) one or more fields or subfields of the MU PPDU 720. For example, the RU allocation information may be omitted, and a non-OFDMA number of users field may be present in the EHT-SIG 726. The user-specific field 728 includes several user fields (not shown for simplicity). The number of user fields may depend on the total number of users associated with the PPDU 720. When configured for transmission to a single user, a single user field may be formatted according to a non-MU-MIMO allocation format. The user field for non-MU-MIMO allocation may include one or more subfields (such as NSS and beamforming subfields) that are not present in the user field for MU-MIMO allocation. When the PPDU is configured for non-OFDMA MU-MIMO communication or the RU is configured for MU-MIMO transmission, multiple user fields may be formatted according to the MU-MIMO allocation format. The user field for MU-MIMO allocation may include a spatial configuration subfield (indicating the number of spatial streams for the STA) that is not present in the user field for non-MU-MIMO allocation.

[0079] Because the new WLAN communication protocol realizes enhanced features, a new preamble design is needed to support the signaling related to the new features and packet formats. In general, each implementation relates to the signaling included in the PHY preamble supporting the new wireless communication protocol, and more specifically, relates to the preamble design supporting the extended range communication or data throughput gain achievable according to the 1EEE 802.11be revision of the IEEE 802.11 standard and the future generations. In some implementations, compared with the preamble design following the existing version of the IEEE 802.11 standard, the preamble design of the present disclosure can be realized using different lengths, modulation schemes or frame structures. For example, the information carried in one or more fields of the PHY preamble can be repeated (in time) to provide an increased signaling gain at the receiving device. In some aspects, such information can be carried in the U-SIG of the PHY preamble. In some other aspects, such information can be carried in the non-legacy signal field of the PHY preamble.

[0080] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. The preamble design of the present implementation may allow for more reliable packet detection, more accurate channel estimation, and more robust decoding of signaling information in non-legacy packets. Signaling refers to a control field or information that can be used by a wireless communication device to interpret another field or part of a packet. Such information may be encoded in the PHY preamble of the packet. However, decoding and processing signaling information consumes time and resources, which may delay the processing of other information carried in the packet. By adjusting the length, modulation scheme, or frame structure associated with the physical layer preamble, various aspects of the present disclosure may allow for early detection of various contents (or lack of such contents) in the physical layer preamble, and provide more time for the receiving device to process such contents.

[0081] Figure 8 FIG. 8 shows an example frame structure of a non-legacy (e.g., EHT) PPDU 800 allocated across multiple subchannels of a wireless channel according to some implementations. In some implementations, the EHT PPDU 800 may be Figure 6 An example of a PPDU 600. Figure 8 In the example of FIG. 8 , the EHT PPDU 800 is shown to include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG signaled or transmitted on multiple 20 MHz sub-channels (or frequency segments) of a 320 MHz wireless channel. In some other implementations, the wireless channel may cover any frequency range, including but not limited to a 160 MHz spectrum, a 240 MHz spectrum, a 480 MHz spectrum, or a 640 MHz spectrum. Figure 8As shown in , the 320 MHz spectrum includes 16 20 MHz sub-channels indexed from lowest to highest (such as from 1st to 16th).

[0082] exist Figure 8 In the example of , L-STF, L-LTF, L-SIG, and RL-SIG are replicated or repeated in each 20 MHz subchannel across the entire 320 MHz spectrum. In some implementations, the U-SIG may be replicated or repeated in each 20 MHz subchannel of a corresponding group of four groups of four consecutive 20 MHz subchannels, where each group of four consecutive 20 MHz subchannels corresponds to an 80 MHz subblock within the PPDU bandwidth. For example, the first four subchannels (1st to 4th) may share the same U-SIG fields and values. The next four subchannels (5th to 8th) may share the same U-SIG fields and values, which may be different from the U-SIG fields or values ​​of the first four subchannels. The next four subchannels (9th to 12th) may share the same U-SIG fields and values, which in turn may be different from the U-SIG fields or values ​​in any of the first eight subchannels. The next four subchannels (13th to 16th) may share the same U-SIG fields and values, which in turn may be different from the U-SIG fields or values ​​in any of the first twelve subchannels. In other words, the U-SIG fields or values ​​may change every 80 MHz. This may allow for greater parallelization of U-SIG information across the various subchannels.

[0083] In some implementations, the EHT-SIG may be signaled on several content channels. Each content channel may be defined by a specific subchannel grouping. For example, a first content channel may carry signaling information for all odd-numbered subchannels (such as the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, and 15th 20MHz subchannels), while a second content channel may carry signaling information for all even-numbered subchannels (such as the 2nd, 4th, 6th, 8th, 10th, 12th, 14th, and 16th 20MHz subchannels). In some implementations, the EHT-SIG may be replicated or repeated per content channel. For example, the (odd-numbered) subchannels associated with the first content channel may share the same EHT-SIG fields and values. The (even-numbered) subchannels associated with the second content channel may share the same EHT-SIG fields and values, which may be different from the EHT-SIG fields or values ​​of the first content channel.

[0084] Similar to U-SIG, the signaling content of the same content channel of EHT-SIG in different 80MHz sub-blocks may be different. The signaling content of the two content channels of EHT-SIG within each 80MHz sub-block is mainly used by the receiving device that processes the non-legacy preamble in that particular 80MHz sub-block. Signaling information specific to other receiving devices that do not process the non-legacy preamble in an 80MHz sub-block may not be carried in the EHT-SIG in that particular 80MHz sub-block.

[0085] In some aspects, L-STF can be used for packet detection. In other words, the receiving device can detect the presence of a PPDU on a wireless channel in response to detecting the L-STF. In addition, short training fields (such as L-STF) can be used by the receiving device to perform automatic gain control (AGC) in the receiver. Via AGC, the receiver can be configured to receive subsequent parts of the PPDU. In order to ensure that most of the L-STF can be used for AGC, it is expected that the receiving device detects the L-STF early in the transmission of the PPDU. Aspects of the present disclosure recognize that the receiving device can achieve more reliable packet detection (or detection of L-STF) by opening its detection bandwidth to more than 20MHz.

[0086] See for example Figure 8 , the L-STF is replicated or repeated on each of the 20MHz subchannels across the bandwidth of the EHT PPDU 800. Specifically, the EHT PPDU 800 includes 16 repetitions (in frequency) of the L-STF that span 16 20MHz subchannels, respectively. In some implementations, the receiving device may listen for the L-STF on multiple 20MHz subchannels. In this way, the receiving device may utilize the repetition of the L-STF in the EHT PPDU to achieve greater gain in L-STF detection. In other words, by listening for the L-STF on multiple 20MHz subchannels, the receiving device may detect the EHT PPDU earlier or more reliably than would otherwise be possible by listening for the L-STF on any single 20MHz subchannel.

[0087] Contrary to L-STF, U-SIG and EHT-SIG may not be copied or repeated on every 20MHz subchannel of the EHT PPDU. Figure 8, the information in the U-SIG may change every 80 MHz, while the information in the EHT-SIG may be different for each content channel and may change every 80 MHz. Due to the changes in content in the U-SIG and EHT-SIG, the achievable gain resulting from repetition in frequency may be significantly reduced. In some implementations, in order to compensate for the limited number of repetitions in the frequency domain, the U-SIG or EHT-SIG may be repeated in the time domain. For example, the information in the U-SIG may be carried on two unique U-SIG symbols in the time domain. Via repetition, the same information may be copied or repeated on two additional U-SIG symbols. Therefore, the U-SIG field may have an overall symbol duration equal to four U-SIG symbols (referred to sequentially in time as "U-SIG-1", "U-SIG-2", "U-SIG-3", and "U-SIG-4").

[0088] In some implementations, U-SIG-2 may be a copy or repetition of U-SIG-1, and U-SIG-4 may be a copy or repetition of U-SIG-3. In other words, U-SIG-1 and U-SIG-2 may carry the same decoded bits, and U-SIG-3 and U-SIG-4 may carry the same decoded bits. In order to indicate the presence of repetition to the receiving device, the second U-SIG symbol (U-SIG-2) may be modulated according to a modulation scheme different from that of the first U-SIG symbol (U-SIG-1). For example, U-SIG-1 may be modulated using BPSK. In some implementations, U-SIG-2 may be modulated using orthogonal BPSK (QBPSK). In response to detecting a change in the modulation scheme from U-SIG-1 to U-SIG-2 (or detecting a modulation scheme associated with U-SIG-2), the receiving device may continue to listen for two additional U-SIG symbols (U-SIG-3 and U-SIG-4).

[0089] In some aspects, the ordering of the decoded bits carried on U-SIG-1 may be different from the ordering of the decoded bits carried on U-SIG-2. In some other aspects, the ordering of the decoded bits carried on U-SIG-3 may be different from the ordering of the decoded bits carried on U-SIG-4. For example, a known modulation scheme (such as BPSK or QBPSK) may be used to map the sequence of decoded bits associated with each U-SIG symbol to a corresponding sequence of modulation symbols. Each modulation symbol may be modulated on a different tone or subcarrier within a given 20 MHz subchannel. In some instances, interference (such as deep fading) in the wireless channel may prevent the transmission of modulation symbols on one or more of the subcarriers. Therefore, by changing the order in which the modulation symbols are modulated on different subcarriers (between two consecutive or duplicated U-SIG symbols), aspects of the present disclosure may increase transmit diversity and further improve the signaling gain that may be achieved via repetition of U-SIG symbols. In some implementations, the decoded bits carried on U-SIG-1 and U-SIG-3 may be interleaved, while the decoded bits carried on U-SIG-2 and U-SIG-4 may not be interleaved.

[0090] The information in the EHT-SIG may be carried on one or more unique EHT-SIG symbols (without repetition in the time domain) in a PPDU configured for transmission to a single user, DL OFDMA, or non-OFDMA MU-MIMO. Via repetition, the same information may be replicated or repeated on one or more additional EHT-SIG symbols. Thus, the EHT-SIG field may have an overall symbol duration equal to twice the number of non-repeating EHT-SIG symbols. In some implementations, each unique EHT-SIG symbol may be followed by its repetition. For example, if the EHT-SIG has an overall symbol duration equal to four EHT-SIG symbols, the first EHT-SIG symbol (EHT-SIG-1) may be a unique EHT-SIG symbol, the second EHT-SIG symbol (EHT-SIG-2) may be a repetition of EHT-SIG-1, the third EHT-SIG symbol (EHT-SIG-3) may be another unique EHT-SIG symbol, and the fourth EHT-SIG symbol (EHT-SIG-4) may be a repetition of EHT-SIG-3. In this way, EHT-SIG-2 and EHT-SIG-4 may carry the same decoded bits as EHT-SIG-1 and EHT-SIG-3, respectively. In some other implementations, all unique EHT-SIG symbols may precede any repetition of the EHT-SIG symbol. For example, if the EHT-SIG has an overall symbol duration equal to four EHT-SIG symbols, the first and second EHT-SIG symbols (EHT-SIG-1 and EHT-SIG-2) may be unique EHT-SIG symbols, while the third and fourth EHT-SIG symbols (EHT-SIG-3 and EHT-SIG-4) may be repetitions of the first and second EHT-SIG symbols, respectively. In this way, EHT-SIG-3 and EHT-SIG-4 may carry the same decoded bits as EHT-SIG-1 and EHT-SIG-2, respectively.

[0091] The receiving device may detect the presence of repetitions in the EHT-SIG based on the modulation scheme associated with the U-SIG-2 (or a change in the modulation scheme between U-SIG-1 and U-SIG-2). In some aspects, the ordering of the decoded bits carried on each unique EHT-SIG symbol may be different from the ordering of the decoded bits carried on the repetitions of the EHT-SIG symbol, for example, to increase transmit diversity and further improve the signaling gain achievable via the repetition of the EHT-SIG symbol. In some implementations, the decoded bits carried on the unique EHT-SIG symbol may be interleaved, while the decoded bits carried on the repetitions of the EHT-SIG symbol may not be interleaved.

[0092] Aspects of the present disclosure recognize that in some PPDU formats (such as Fig. 7A The EHT-SIG may not be present in the TB PPDU 700). The presence of the EHT-SIG (or its absence) may affect the timing of one or more subsequent fields of the EHT PPDU. Figure 6 , a non-legacy STF (such as EHT-STF) may follow the EHT-SIG in the SU and MU PPDU formats (such as Figure 7B ), and may be immediately following the U-SIG in the TB PPDU format. Similar to the L-STF, the EHT-STF may be used by the receiving device to perform AGC in the receiver. More specifically, the EHT-STF may be used by the receiving device to reconfigure its receiver to receive the EHT modulated portion of the PPDU. Therefore, it is desirable for the receiving device to detect the EHT-STF early so that most of the EHT-STF may be used for AGC. Specifically, it may be desirable for the receiving device to know whether the EHT-STF is immediately following the U-SIG or immediately following the EHT-SIG.

[0093] As described above, the presence of the EHT-SIG depends on the PPDU format implemented for a particular transmission. Figure 6 The PPDU format is indicated in the PPDU type and compression mode field 636 of the U-SIG. However, decoding and processing the information in the U-SIG consumes time and resources, which may delay the detection or processing of the EHT-STF. In some implementations, the presence (or absence) of the EHT-SIG in the EHT PPDU preamble can be indicated by changing the modulation scheme associated with one or more U-SIG symbols. For example, the third symbol of the U-SIG (U-SIG-3) can be modulated according to QBPSK or BPSK to indicate the presence or absence of the EHT-SIG in the preamble, respectively. In response to detecting that the U-SIG-3 is modulated using QBPSK, the receiving device may expect the EHT-STF to occur at least two symbol durations (depending on the duration of the EHT-SIG) after the U-SIG. In response to detecting that the U-SIG-3 is modulated using BPSK, the receiving device may expect the EHT-STF to occur immediately after the U-SIG.

[0094] Aspects of the present disclosure further recognize that the presence of the EHT-SIG can provide a buffer (or additional time) for the receiving device to decode and process the information in the U-SIG, and therefore determine the start of the EHT-STF. In other words, when the EHT-SIG is present in the preamble, the receiving device can determine the presence of the EHT-SIG before it begins to receive the EHT-STF (based on the PPDU format indicated in the U-SIG). However, when the EHT-SIG is not present in the preamble, the receiving device may not be able to determine the absence of the EHT-SIG before it begins to receive the EHT-STF (based on the PPDU format indicated in the U-SIG). In some implementations, in the absence of the EHT-SIG (such as in a TB PPDU), one or more padding symbols can be inserted between the U-SIG and the EHT-STF to provide a buffer (similar to the EHT-SIG) for the receiving device to decode and process the information in the U-SIG, and therefore determine the start of the EHT-STF.

[0095] Fig.9A An example PHY preamble 900 for a non-legacy PPDU is shown according to some implementations. In some implementations, the PHY preamble 900 may be an example of a PHY preamble that includes Figure 6 The PHY preamble 900 includes L-STF 901, L-LTF 902, L-SIG 903, RL-SIG 904, U-SIG 905, EHT-SIG 906, EHT-STF 907, and EHT-LTF 908. Fig.9A In the example of , U-SIG 905 includes four U-SIG symbols (U-SIG-1, U-SIG-2, U-SIG-3, and U-SIG-4), and EHT-SIG 906 includes two EHT-SIG symbols (EHT-SIG-1 and EHT-SIG-2). More specifically, U-SIG-2 may be a copy of U-SIG-1, U-SIG-4 may be a copy of U-SIG-3, and EHT-SIG-2 may be a copy of EHT-SIG-1. In some implementations, U-SIG-2 may be modulated using QBPSK to indicate the repetition of the PHY preamble 900 in U-SIG 905 and EHT-SIG 906. In some other implementations, U-SIG-3 may be further modulated using QBPSK to indicate (at the PHY level) the presence of EHT-SIG 906.

[0096] The receiving device may detect the PHY preamble 900 based on the L-STF 901. In some implementations, the receiving device may detect the L-STF 901 on multiple 20 MHz subchannels. The receiving device may further detect the presence of the U-SIG 905 in the PHY preamble 900 based on the combination of the L-SIG 903 and the RL-SIG 904. For example, the receiving device may determine that the PPDU complies with the 1EEE 802.11ax amendment or later generation of the IEEE 802.11 standard based on the presence of the RL-SIG 904. The receiving device may further determine that the PPDU further complies with the IEEE 802.11be amendment to the 1EEE 802.11 standard (where L_LEN%3==0) based on the length field (L_LEN) of the L-SIG 903.

[0097] The receiving device may further determine that U-SIG-2 is modulated using QBPSK. Based on this determination, the receiving device may determine that U-SIG 905 includes two additional U-SIG symbols (U-SIG-3 and U-SIG-4). In some implementations, the receiving device may further determine that EHT-SIG 906 includes one or more additional EHT-SIG symbols (EHT-SIG-2) based on the determination that U-SIG-2 is modulated using QBPSK. The receiving device may further determine that U-SIG-3 is further modulated using QBPSK. In response to this determination, the receiving device may determine that one or more additional fields or subfields (such as EHT-SIG 906) immediately follow U-SIG 905 before EHT-STF 907. Therefore, the receiving device may be prepared to initiate or perform AGC starting from two codeword durations after U-SIG 905.

[0098] Fig. 9B Another example PHY preamble 910 for a non-legacy PPDU according to some implementations is shown. In some implementations, the PHY preamble 910 may be an example of a PHY preamble that includes Figure 6 The PHY preamble 910 includes L-STF 911, L-LTF 912, L-SIG 913, RL-SIG 914, U-SIG 915, EHT-STF 917, and EHT-LTF 918. Fig. 9BIn the example of , U-SIG 915 includes four U-SIG symbols (U-SIG-1, U-SIG-2, U-SIG-3, and U-SIG-4). More specifically, U-SIG-2 may be a copy of U-SIG-1, and U-SIG-4 may be a copy of U-SIG-3. In some implementations, U-SIG-2 may be modulated using QBPSK to indicate that the PHY preamble 910 includes a repetition in U-SIG 915. In some other implementations, U-SIG-3 may be modulated using BPSK to indicate (at the PHY level) the absence of an EHT-SIG.

[0099] The receiving device may detect the PHY preamble 910 based on the L-STF 911. In some implementations, the receiving device may detect the L-STF 911 on multiple 20 MHz subchannels. The receiving device may further detect the presence of the U-SIG 915 in the PHY preamble 910 based on the combination of the L-SIG 913 and the RL-SIG 914. For example, the receiving device may determine that the PPDU complies with the 1EEE 802.11ax amendment or later generation of the IEEE 802.11 standard based on the presence of the RL-SIG 914. The receiving device may further determine that the PPDU further complies with the IEEE 802.11be amendment to the 1EEE 802.11 standard (where L_LEN%3==0) based on the length field (L_LEN) of the L-SIG 913.

[0100] The receiving device may further determine that U-SIG-2 is modulated using QBPSK. Based on this determination, the receiving device may determine that U-SIG 915 includes two additional U-SIG symbols (U-SIG-3 and U-SIG-4). The receiving device may further determine that U-SIG-3 is modulated using BPSK. In response to this determination, the receiving device may determine that EHT-STF 917 follows U-SIG 915 immediately. Therefore, the receiving device may be prepared to start initiating or performing AGC immediately after U-SIG 915.

[0101] Fig. 10A An example PHY preamble 1000 for a non-legacy PPDU according to some implementations is shown. In some implementations, the PHY preamble 1000 may be an example of a PHY preamble that includes Figure 6 The PHY preamble 1000 includes L-STF 1001, L-LTF 1002, L-SIG 1003, RL-SIG 1004, U-SIG 1005, EHT-SIG 1006, EHT-STF 1007, and EHT-LTF 1008. Fig. 10A In the example of , U-SIG 1005 includes four U-SIG symbols (U-SIG-1, U-SIG-2, U-SIG-3, and U-SIG-4), and EHT-SIG 1006 includes two EHT-SIG symbols (EHT-SIG-1 and EHT-SIG-2). More specifically, U-SIG-2 may be a copy of U-SIG-1, U-SIG-4 may be a copy of U-SIG-3, and EHT-SIG-2 may be a copy of EHT-SIG-1. In some implementations, U-SIG-2 may be modulated using QBPSK to indicate the repetition of the PHY preamble 1000 in U-SIG 1005 and EHT-SIG 1006. However, as with reference Fig.9A and Fig. 9B The described implementation differs in that QBPSK is not used to modulate the U-SIG-3 to indicate the presence of the EHT-SIG 1006 .

[0102] The receiving device may detect the PHY preamble 1000 based on the L-STF 1001. In some implementations, the receiving device may detect the L-STF 1001 on multiple 20 MHz subchannels. The receiving device may further detect the presence of the U-SIG 1005 in the PHY preamble 1000 based on a combination of the L-SIG 1003 and the RL-SIG 1004. For example, the receiving device may determine that the PPDU complies with the 1EEE 802.11ax amendment or later generation of the IEEE 802.11 standard based on the presence of the RL-SIG 1004. The receiving device may further determine that the PPDU further complies with the IEEE 802.11be amendment to the 1EEE 802.11 standard (where L_LEN%3==0) based on the length field (L_LEN) of the L-SIG 1003.

[0103] The receiving device may further determine that U-SIG-2 is modulated using QBPSK. Based on this determination, the receiving device may determine that U-SIG 1005 includes two additional U-SIG symbols (U-SIG-3 and U-SIG-4). In some implementations, the receiving device may further determine that EHT-SIG 1006 includes one or more additional EHT-SIG symbols (EHT-SIG-2) based on the determination that U-SIG-2 is modulated using QBPSK. After decoding and processing U-SIG 1005, the receiving device may further determine that the PHY preamble 1000 includes EHT-SIG 1006. For example, the receiving device may determine that the PHY preamble 1000 is implemented according to the MU PPDU format (based on the PPDU type and compression mode fields in U-SIG 1005) and know the length of the EHT-SIG field based on the EHT-SIG number of symbols field in U-SIG 1005. In some implementations, the receiving device may detect the PPDU format upon receiving at least a portion of the EHT-SIG 1006. Thus, the receiving device may be prepared to initiate or perform AGC immediately after the EHT-SIG 1006.

[0104] Fig. 10B Another example PHY preamble 1010 for a non-legacy PPDU according to some implementations is shown. In some implementations, the PHY preamble 1010 may be an example of a PHY preamble that includes Figure 6 The PHY preamble 1010 includes L-STF 1011, L-LTF 1012, L-SIG 1013, RL-SIG 1014, U-SIG 1015, padding 1016, EHT-STF 1017, and EHT-LTF 1018. Fig. 10B In the example of , U-SIG 1015 includes four U-SIG symbols (U-SIG-1, U-SIG-2, U-SIG-3, and U-SIG-4). More specifically, U-SIG-2 may be a copy of U-SIG-1, and U-SIG-4 may be a copy of U-SIG-3. In some implementations, U-SIG-2 may be modulated using QBPSK to indicate that the PHY preamble 1010 includes a repetition in U-SIG 1015.

[0105] The receiving device may detect the PHY preamble 1010 based on the L-STF 1011. In some implementations, the receiving device may detect the L-STF 1011 on multiple 20 MHz subchannels. The receiving device may further detect the presence of the U-SIG 1015 in the PHY preamble 1010 based on a combination of the L-SIG 1013 and the RL-SIG 1014. For example, the receiving device may determine that the PPDU complies with the 1EEE 802.11ax amendment or later generation of the IEEE 802.11 standard based on the presence of the RL-SIG 1014. The receiving device may further determine that the PPDU further complies with the IEEE 802.11be amendment to the 1EEE 802.11 standard (where L_LEN%3==0) based on the length field (L_LEN) of the L-SIG 1013.

[0106] The receiving device may further determine that U-SIG-2 is modulated using QBPSK. Based on this determination, the receiving device may determine that U-SIG 1015 includes two additional U-SIG symbols (U-SIG-3 and U-SIG-4). After decoding and processing U-SIG 1015, the receiving device may further determine that the PHY preamble 1010 does not include an EHT-SIG. For example, the receiving device may determine that the PHY preamble 1010 is implemented according to a TB PPDU format (based on the PPDU type and compression mode fields in U-SIG 1015). In some implementations, the receiving device may detect the PPDU format when receiving the padding symbol 1016. Therefore, the receiving device may be prepared to initiate or perform AGC immediately after processing U-SIG 1015.

[0107] Aspects of the present disclosure recognize that the above reference Figures 9A-10B The described packet format can further facilitate communications over an extended range. For example, existing versions of the IEEE 802.11 standard support an extended range (ER) packet format suitable for wireless communications over larger distances (e.g., in outdoor environments). Specifically, the 1EEE802.11ax revision to the IEEE 802.11 standard defines a HE ER SU PPDU format that includes a repeated HE signal field (HE-SIG-A). In other words, the information carried on the HE-SIG-A is transmitted twice in the PHY preamble. Since the HE-SIG-A carries the signaling required to decode or interpret subsequent fields or portions of the HE PPDU, the repetition of the HE-SIG-A enables more robust and reliable transmission of the HE ER SU PPDU over a larger distance. Similarly, the above referenced Figures 9A-10BThe repetition of U-SIG (and EHT-SIG) in the described packet format is used to extend the communication range of the EHT PPDU.

[0108] Fig.11 An example ER PPDU 1100 is shown according to some implementations. In some implementations, the ER PPDU 1100 may be Figure 6 1100. More specifically, the ER PPDU 1100 may be used for wireless communication over an extended range, such as, for example, in an outdoor environment. The ER PPDU 1100 includes an L-STF 1101, an L-LTF 1102, an L-SIG 1103, an RL-SIG 1104, a U-SIG 1105, an EHT-STF 1107, an EHT-LTF 1108, and a data field 1109, each of which may correspond to the L-STF 608, L-LTF 610, L-SIG 612, RL-SIG 614, U-SIG 616, EHT-STF 622, EHT-LTF 624, and data field 626 of the PPDU 600, respectively. In some implementations, the ER PPDU 1100 may further include an EHT-SIG 1106 , which may correspond to the EHT-SIG 618 of the PPDU 600 .

[0109] In some implementations, to improve the reliability and robustness of the ER PPDU 1100 over longer distances, the U-SIG 1105 may be repeated (in the time domain). For example, the information in the U-SIG 1105 may be carried on two unique U-SIG symbols. However, via repetition, the same information may be duplicated or repeated on two additional U-SIG symbols. Thus, the U-SIG 1105 may have an overall symbol duration equal to four U-SIG symbols, U-SIG-1, U-SIG-2, U-SIG-3, and U-SIG-4. In some implementations, the U-SIG-2 may be a duplicate or repetition of the U-SIG-1, and the U-SIG-4 may be a duplicate or repetition of the U-SIG-3. In other words, the U-SIG-1 and U-SIG-2 may carry the same decoded bits (decoded bits A), and the U-SIG-3 and U-SIG-4 may carry the same decoded bits (decoded bits B).

[0110] In some aspects, an interleaving technique may be used to reorder the decoded bits carried on each of U-SIG-1 and U-SIG-3. Thus, the order of the decoded bits carried on U-SIG-1 may be different from the order of the decoded bits carried on U-SIG-2, and the order of the decoded bits carried on U-SIG-3 may be different from the order of the decoded bits carried on U-SIG-4. For example, a known modulation scheme (such as BPSK) may be used to map the sequence of decoded bits associated with each U-SIG symbol to a corresponding sequence of modulation symbols. Each modulation symbol may be modulated on a different tone or subcarrier within a 20 MHz subchannel. In some cases, interference in the wireless channel (such as deep fading) may prevent the transmission of modulation symbols on one or more of the subcarriers. Thus, by changing the order in which modulation symbols are modulated on different subcarriers (between duplicated U-SIG symbols), aspects of the present disclosure may increase transmit diversity and further improve the signaling gain that may be achieved through repetition of U-SIG symbols. In some implementations, the decoded bits carried on U-SIG-1 and U-SIG-3 may be interleaved, while the decoded bits carried on U-SIG-2 and U-SIG-4 may not be interleaved.

[0111] In some implementations, U-SIG-2 may be modulated according to a modulation scheme different from that of U-SIG-1 to indicate the presence of repetitions in U-SIG 1105. For example, U-SIG-1 may be modulated using BPSK, and U-SIG-2 may be modulated using quadrature BPSK (QBPSK). In response to detecting a change in the modulation scheme from U-SIG-1 to U-SIG-2 (or detecting that U-SIG-2 is modulated according to QBPSK), the receiving device may continue to listen for two additional U-SIG symbols (U-SIG-3 and U-SIG-4). In some implementations, repetitions in U-SIG 1105 may be present in other non-legacy PPDU formats (other than the ER PPDU format). Therefore, changing the modulation scheme associated with U-SIG-2 may not itself be sufficient to classify PPDU 1100 as an ER PPDU.

[0112] In some implementations, the PHY version identifier in the U-SIG 1105 can further distinguish the ER PPDU 1100 from other non-legacy PPDU formats. The PHY version identifier can indicate the version of the wireless communication protocol associated with the PPDU 1100. Figure 6, the version identifier may be provided as a subfield of the version independent field 632 of the U-SIG 616. In some implementations, the PPDU 1100 may be classified as an ER PPDU when the PHY version identifier subfield of the U-SIG 1105 indicates the IEEE 802.11be amendment to the IEEE 802.11 standard. In other words, the receiving device may determine that the PPDU 1100 is formatted as an ER PPDU via detecting duplication in the U-SIG 1105 (based on the modulation scheme associated with the U-SIG-2) and determining that the PPDU 1100 is transmitted in accordance with the IEEE 802.11be amendment to the IEEE 802.11 standard (based on the version identifier subfield of the U-SIG 1105).

[0113] In some implementations, the ER PPDU 1100 may further include an EHT-SIG 1106. In some aspects, the EHT-SIG 1106 may carry one or more overflow bits from the U-SIG 1105. In some other aspects, the EHT-SIG 1106 may carry user-specific information for one or more recipients of the ER PPDU 1100. For example, if the ERP PDU is for transmission to a single user, the EHT-SIG 1106 may include a user-specific field with a single user field. In some implementations, for a single user, such as with reference to Figure 8 As described, the ER PPDU 1100 may be formatted according to the MU PPDU format. In addition, the EHT-SIG 1106 may be transmitted using a fixed code rate and a fixed modulation scheme optimized for ER communication. For example, in some aspects, the information carried on the EHT-SIG 1106 may be encoded at a rate equal to 1 / 2 and may be modulated according to a BPSK modulation scheme. In some implementations, the information carried on the EHT-SIG 1106 may be encoded at a rate equal to 1 / 2 and may be modulated according to a BPSK modulation and a dual carrier modulation (DCM) scheme.

[0114] In some implementations, the EHT-SIG 1106 may be further repeated (in time). Fig.11In the example of , the information in EHT-SIG 1106 may be carried on a unique EHT-SIG symbol. However, via repetition, the same information may be replicated or repeated on additional EHT-SIG symbols. Thus, EHT-SIG 1106 may have an overall symbol duration equal to two EHT-SIG symbols, EHT-SIG-1 and EHT-SIG-2. In some implementations, EHT-SIG-2 may be a replication or repetition of EHT-SIG-1. In other words, EHT-SIG-1 and EHT-SIG-2 may carry the same decoded bits (decoded bits C). In some aspects, interleaving techniques may be used to reorder the decoded bits carried on EHT-SIG-1, for example, to increase transmit diversity and further improve the signaling gain achievable via repetition of EHT-SIG symbols. In some implementations, the decoded bits carried on EHT-SIG-1 may be interleaved, while the decoded bits carried on EHT-SIG-2 may not be interleaved. The receiving device may detect the presence of repetition in the EHT-SIG based on the modulation scheme associated with the U-SIG-2 (or the change in modulation scheme between U-SIG-1 and U-SIG-2).

[0115] In some other implementations, when the ER PPDU is only for transmission to a single user, the EHT-SIG 1106 may be omitted from the ER PPDU 1100 for transmission to a single user (further referred to as the ER SU PPDU). Thus, one or more fields or subfields that would otherwise be included in the EHT-SIG 1106 (such as the user field or the U-SIG overflow) may be combined with the U-SIG 1105 instead. In order to support additional signaling in the U-SIG 1105 without increasing overhead, some fields or subfields associated with the U-SIG 1105 or the EHT-SIG 1106 may be omitted, and some fields or subfields of the U-SIG 1105 or the EHT-SIG 1106 may be shortened or compressed. For example, since the ER PPDU 1100 is intended for only a single recipient device, the STA ID subfield may be omitted from the user field. More specifically, the recipient device may determine the STA ID based on the MAC header of the ER PPDU 1100. By eliminating the EHT-SIG 1106, multiple fields or subfields carrying signaling for the EHT-SIG 1106 (such as EHT-SIG compression, EHT-SIG MCS, and EHT-SIG number of symbols) may be omitted from the U-SIG 1105. The PPDU format (or PPDU type) subfield may further be omitted from the U-SIG 1105 because the classification of the ER PPDU is based on the modulation scheme associated with the U-SIG-2 and PHY version identifier subfields.

[0116] Aspects of the present disclosure further recognize that, to support extended range communications, the ER PPDU 1100 may be transmitted at a relatively low data rate (such as MCSO-MSC3) on a limited number of spatial streams (such as 1 or 2 spatial streams) within a single 20 MHz subchannel (and the data portion 1109 may be transmitted on an even smaller subset of tones or subcarriers within the 20 MHz subchannel). Given such restrictions on the ER PPDU format, the number of fields or subfields of the U-SIG 1105 (such as bandwidth, MCS, number of LTFs, and mid-order signal period) may be shortened or compressed, and multiple additional fields or subfields (such as punctured channel information) may be omitted from the U-SIG 1105. In some implementations, two or more fields or subfields of the U-SIG 1105 may be jointly encoded to further reduce signaling overhead. For example, a single set of CRC and tail bits may be associated with multiple fields of the U-SIG 1105. By omitting, shortening, and merging fields in the U-SIG 1105 , information that would otherwise be transmitted in the EHT-SIG 1106 may instead be transmitted in the U-SIG 1105 without increasing the size or length of the U-SIG 1105 .

[0117] Fig.12 FIG. 1 shows an example frame structure for an ER PPDU 1200 according to some implementations. In some implementations, the ERP PDU 1200 may be Fig.11 The ER PPDU 1100 is an example of an ER PPDU 1100. The ER PPDU 1100 includes an L-STF 1201, an L-LTF 1202, an L-SIG 1203, an RL-SIG 1204, a U-SIG 1205, an EHT-STF 1207, an EHT-LTF 1208, and a data field 1209, which may correspond to the L-STF 1101, L-LTF 1102, L-SIG 1103, RL-SIG 1104, U-SIG 1105, EHT-STF 1107, EHT-LTF 1108, and data field 1109 of the ER PPDU 1100, respectively. Fig.12 In the example of , the ERP PDU 1200 does not include the EHT-SIG. In fact, the U-SIG 1205 includes a set of version-independent fields 1210 , a set of version-dependent fields 1211 , and a user field 1212 .

[0118] In some implementations, the version-independent field 1210 may include a PHY version identifier subfield (3 bits), an uplink or downlink subfield (1 bit), a transmit opportunity (TXOP) duration subfield (7 bits), a BSS color subfield (6 bits), and a PPDU bandwidth subfield (3 bits). Therefore, the length of the version-independent field 1210 may be 20 bits. In some implementations, the version-dependent field 1211 may include a spatial reuse subfield (4 bits), a guard interval (GI) and LTF size subfield (2 bits), an LDPC additional symbol segment subfield (1 bit), a number of spatial streams (NSS) and a mid-sequence signal period subfield (2 bits), a Doole subfield (1 bit), a STBC subfield (1 bit), a beam change subfield (1 bit), a pre-FEC filling factor subfield (2 bits), and a packet extension (PE) disambiguation subfield (1 bit). Therefore, the length of the version-dependent field 1211 may be 15 bits. In some implementations, the user field 1212 may include a beamforming subfield (1 bit), a coding subfield (1 bit), and an MCS subfield (2 bits), the MCS subfield may indicate whether DCM (with BPSK) is used. Thus, the length of the user field 1212 may be 4 bits.

[0119] exist Fig.12 In the example of , the version-independent field 1210, the version-dependent field 1211, and the user field 1212 represent a combined 39 bits of signaling information. In some implementations, the version-independent field 1210, the version-dependent field 1211, and the user field 1212 may be jointly encoded with a single CRC (4 bits) and tail bits (6 bits). Thus, the signaling information in U-SIG 1205 represents a total management burden of 49 bits. In contrast, 2 U-SIG symbols may carry a combined 52 bits. Thus, in Fig.12 In the example of , U-SIG 1205 may carry any relevant user-specific information (which would otherwise be carried on the EHT-SIG), with the 3 unused bits being reserved.

[0120] Various aspects of the present disclosure recognize that in some PPDU formats (such as Fig. 7A TB PPDU 700 or Fig.12 The EHT-SIG may not be present in the ERP PDU 1200 of the ER PPDU. The presence of the EHT-SIG (or its absence) may affect the timing of one or more subsequent fields of the ER PPDU. Fig.11, the EHT-STF 1107 may be immediately following the EHT-SIG 1106 (in an implementation of the ER PPDU 1100 that includes the EHT-SIG 1106) or immediately following the U-SIG 1105 (in an implementation of the ER PPDU 1100 that does not include the EHT-SIG 1106). As described above, the receiving device may use the EHT-STF to perform AGC in the receiver. More specifically, the receiving device may use the EHT-STF to configure (or reconfigure) its receiver to receive the EHT modulation portion of the EHT PPDU. Therefore, it is expected that the receiving device detects the EHT-STF early so that most of the EHT-STF can be used for AGC. More specifically, the receiving device may need to know whether the EHT-STF is immediately following the U-SIG or immediately following the EHT-SIG.

[0121] As described above, the presence (or absence) of the EHT-SIG depends on the PPDU format implemented for a particular transmission. In the present implementation, the ER PPDU format is classified based in part on the version identifier carried on the U-SIG. However, decoding and processing the information in the U-SIG consumes time and resources, which may delay the detection or processing of the EHT-STF. In some implementations, the presence (or absence) of the EHT-SIG in the ER PPDU preamble may be indicated by changing the modulation scheme associated with one or more U-SIG symbols. For example, the third symbol (U-SIG-3) of the U-SIG may be modulated according to QBPSK or BPSK to indicate the presence or absence of the EHT-SIG in the preamble, respectively. In response to detecting that the U-SIG-3 is modulated using QBPSK, the receiving device may expect the EHT-STF to occur at least two symbol durations (corresponding to the duration of the EHT-SIG) after the U-SIG (as shown in reference to FIG. 1 ). Fig.9A In response to detecting that U-SIG-3 is modulated using BPSK, the receiving device may expect EHT-STF to occur immediately after U-SIG (as described in reference Fig. 9B described).

[0122] As described above, the presence of the EHT-SIG may also provide a buffer (or additional time) for the receiving device to decode and process the information in the U-SIG and thus determine the start of the EHT-STF. In other words, when the EHT-SIG is present in the preamble, the receiving device may determine the presence of the EHT-SIG based on the PPDU format indicated in the U-SIG before it starts receiving the EHT-STF (as described in reference to FIG. Fig. 10AHowever, when the EHT-SIG is not present in the preamble, the receiving device may not be able to determine the absence of the EHT-SIG before it begins receiving the EHT-STF (based on the PPDU format indicated in the U-SIG). In some implementations, in the absence of the EHT-SIG, one or more padding symbols may be inserted between the U-SIG and the EHT-STF to provide a buffer for the receiving device to decode and process the information in the U-SIG and thus determine the start of the EHT-STF (such as with reference to Fig. 10B described).

[0123] Fig.13A 1 is a flowchart illustrating an example process 1300 for wireless communication supporting PHY preamble design according to some implementations. In some implementations, the process 1300 may be performed by a STA (such as a Figure 1 and 5B In some other implementations, the process 1300 may be performed by a wireless communication device operating as an AP (such as one of the STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0124] In some implementations, in block 1301, process 1300 begins by receiving a packet including a physical layer preamble, the physical layer preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0. In block 1302, process 1300 continues by detecting one or more modulation schemes associated with the U-SIG. In block 1303, process 1300 continues by determining a format of the packet based on the detected modulation scheme associated with the U-SIG.

[0125] Fig. 13B 1 is a flowchart illustrating an example process 1310 for wireless communication supporting PHY preamble design according to some implementations. In some implementations, the process 1310 may be performed by a STA (such as a Figure 1 and 5B In some other implementations, process 1310 may be performed by a wireless communication device operating as an AP (such as one of STAs 104 or 504, respectively). Figure 1 and 5AThe method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0126] See for example Fig.13A , process 1310 may be a more detailed implementation of the operations for detecting one or more modulation schemes associated with the U-SIG in block 1302 of process 1300. For example, process 1310 may begin in block 1311 after receiving a packet in block 1301 and before determining the format of the packet in block 1303. In block 1311, process 1310 begins by determining that a first symbol of the U-SIG is modulated according to a BPSK modulation scheme. In block 1312, process 1310 continues by determining that a second symbol of the U-SIG is modulated according to a QBPSK modulation scheme. In some implementations, process 1310 may continue to box 1313 to perform the following operations: based on determining that the second codeword of the U-SIG is modulated according to the QBPSK modulation scheme, determine that the U-SIG further includes at least a third codeword and a fourth codeword, wherein the first codeword of the U-SIG carries the same decoded bits as the second codeword of the U-SIG, and the third codeword of the U-SIG carries the same decoded bits as the fourth codeword of the U-SIG.

[0127] In some implementations, each of the first symbol and the second symbol may be transmitted on a plurality of subcarriers, wherein the decoded bits of the first symbol are modulated on the plurality of subcarriers in a different order than the decoded bits of the second symbol. In some implementations, each of the third symbol and the fourth symbol may be transmitted on a plurality of subcarriers, wherein the decoded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the decoded bits of the fourth symbol.

[0128] In some implementations, a determination may be made that the packet follows a non-legacy ER packet format based on a value of a version identifier subfield of the U-SIG and a determination that a second symbol of the U-SIG is modulated according to a QBPSK modulation scheme. In some aspects, the preamble may further include a non-legacy signal field immediately following the U-SIG, wherein the non-legacy signal field includes a single user field and one or more overflow bits from the U-SIG. In some aspects, the U-SIG may include a user field that carries user-specific information for a single user, wherein the preamble further includes a non-legacy STF immediately following the U-SIG.

[0129] Fig. 13C 13. A flowchart illustrating an example process 1320 for wireless communication supporting PHY preamble design according to some implementations is shown. In some implementations, the process 1320 may be performed by a STA (such as a STA, respectively Figure 1and 5B In some other implementations, process 1320 may be performed by a wireless communication device operating as an AP (such as one of STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0130] See for example Fig.13A , process 1320 may begin in block 1321 after determining the format of the packet in block 1303 of process 1300. In block 1321, process 1320 begins by determining the timing of a non-legacy STF of a physical layer preamble relative to a U-SIG based on the format of the packet. In block 1322, process 1320 continues by initiating AGC based on the timing of the non-legacy STF. In some implementations, the packet may include one or more padding symbols between the U-SIG and the non-legacy STF.

[0131] Fig.14 1400 for wireless communication supporting PHY preamble design according to some implementations. In some implementations, the process 1400 may be performed by a STA (such as a Figure 1 and 5B In some other implementations, the process 1400 may be performed by a wireless communication device operating as an AP (such as one of the STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0132] In some implementations, in block 1401, process 1400 begins by generating a packet including a physical layer preamble, the physical layer preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0. In block 1402, process 1400 continues by modulating a first symbol of the U-SIG according to a BPSK modulation scheme. In block 1403, process 1400 continues by modulating a second symbol of the U-SIG according to a QBPSK modulation scheme. In block 1404, process 1400 continues by transmitting the packet on a wireless channel.

[0133] In some implementations, the U-SIG may further include at least a third symbol and a fourth symbol, wherein the first symbol of the U-SIG carries the same decoded bits as the second symbol of the U-SIG, and the third symbol of the U-SIG carries the same decoded bits as the fourth symbol of the U-SIG. In some aspects, the decoded bits of the first symbol may be modulated on multiple subcarriers in a different order than the decoded bits of the second symbol. In some aspects, the decoded bits of the third symbol may be modulated on multiple subcarriers in a different order than the decoded bits of the fourth symbol. In some aspects, the packet may include one or more padding symbols between the U-SIG and the non-legacy STF of the physical layer preamble.

[0134] In some implementations, the packet may follow a non-legacy ER packet format having a bandwidth equal to 20 MHz. In some aspects, the preamble may further include a non-legacy signal field immediately following the U-SIG, wherein the non-legacy signal field includes a single user field and one or more overflow bits from the U-SIG. In some aspects, the U-SIG may further include a user field carrying user-specific information for a single user, wherein the preamble further includes a non-legacy STF immediately following the U-SIG.

[0135] The wireless range of a wireless communication device may be related to its transmit power level. For example, a wireless signal transmitted at a higher power level generally travels farther than a wireless signal transmitted at a lower power level. Many government agencies and regulations impose power spectral density (PSD) limits on the transmit power of wireless communication devices. PSD limits can limit the total transmit power of a wireless communication device and the energy of out-of-band transmission. For example, a transmitting device can use a relatively low transmit power level to minimize the signal distortion caused by its power amplifier, for example, so that a receiving device can receive and successfully decode information modulated onto the transmitted wireless signal. The transmitting device can further maintain its transmit power at a level that ensures that its power amplifier operates primarily in a linear region, for example, to minimize signal distortion.

[0136] In some implementations, the wireless communication device disclosed herein can increase the accuracy of channel estimation by increasing the power level used to transmit one or more long training fields (LTFs) of a packet preamble. Specifically, increasing the transmit power level of one or more LTFs that can be used for channel estimation can increase the SINR of the one or more LTFs, which can result in more accurate channel estimation. Although allowing more accurate channel estimation, increasing the power level used to transmit one or more LTFs can cause the total output power level of the wireless communication device to violate applicable PSD limits. Additionally, increasing the power level used to transmit one or more LTFs can increase the amount of signal distortion caused by nonlinearities in a power amplifier provided in a transmission chain of the wireless communication device.

[0137] Thus, implementations of the subject matter disclosed herein may allow a wireless communication device to transmit one or more LTFs of a packet preamble at a greater power level to achieve more accurate channel estimation without violating applicable PSD limits and without signal distortion. In some implementations, the wireless communication device may apply an additional amount of transmit power to one or more LTFs, and may adjust the transmit power level applied to other portions of the packet based on the additional amount of transmit power, the duration of the one or more LTFs, and the PSD limit to maintain the total output power level of the wireless communication device over the frequency bandwidth below the PSD limit. The PSD limit is typically defined on a per-frequency segment basis (such as 5dBm / MHz for APs and -1dBm / MHz for non-AP STAs in some frequency spectra). In this way, a wireless communication device transmitting wireless packets over a relatively large frequency bandwidth may use a greater transmit power level than a wireless communication device transmitting wireless packets over a relatively small frequency bandwidth.

[0138] In addition, PSD limits are typically based on the total output power of the wireless communication device measured over a period of time, rather than on the instantaneous transmit power level. Thus, the wireless communication device may increase the transmit power level of one or more LTFs (to increase the accuracy of the channel estimate) and comply with the applicable PSD limit by reducing the transmit power level of one or more other portions of the packet by an amount and for a duration that compensates for the increased transmit power level applied to the LTFs.

[0139] Fig.15 1 is a flowchart illustrating an example process 1500 for supporting wireless communication with increased transmit power of a training field of a PHY preamble according to some implementations. In some implementations, the process 1500 may be performed by a STA (such as a Figure 1 and 5BIn some other implementations, the process 1500 may be performed by a wireless communication device operating as an AP (such as one of the STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0140] In some implementations, in block 1502, process 1500 begins by formatting a packet for wireless transmission over a frequency bandwidth, the packet including a physical layer (PHY) preamble, the PHY preamble including one or more long training fields (LTFs). In block 1504, process 1500 continues by determining a transmit power level for wireless transmission of the packet based at least in part on a power spectral density (PSD) limit corresponding to the frequency bandwidth. In block 1506, process 1500 continues by determining an additional transmit power amount for at least one of the LTFs of the PHY preamble. In block 1508, process 1500 continues by adjusting the transmit power level based on the additional transmit power amount, the duration of the at least one LTF, and the PSD limit to maintain a total output power level of the wireless communication device over the frequency bandwidth below the PSD limit. In block 1510, process 1500 continues by transmitting a packet based on the adjusted transmit power level, the transmission comprising transmitting at least one LTF at the sum of the adjusted transmit power and the additional transmit power amount, and comprising transmitting one or more other fields of the PHY preamble at the adjusted transmit power level. In some implementations, the at least one LTF may be one or more of: a legacy LTF (L-LTF), a high throughput (HT) LTF (HT-LTF), a high efficiency (HE) LTF (HE-LTF), or an extremely high throughput (EHT) LTF (EHT-LTF).

[0141] In some implementations, the determination of the amount of boosted transmit power for at least one LTF may further be based on a signal to interference plus noise ratio (SINR) associated with transmission of the packet. In some other implementations, the determination of the amount of boosted transmit power for at least one LTF may further be based on a signal to interference plus noise ratio (SINR) threshold for channel estimation.

[0142] In some implementations, the determination of the transmit power level may further be based on the number of tones used to transmit the preamble. In some other implementations, the determination of the transmit power level may further be based on the distribution of the number of tones across the frequency bandwidth.

[0143] In some implementations, the adjustment of the transmit power level may further be based on an output power backoff (OBO) value. In some instances, the OBO value may be selected to reduce signal distortion caused by one or more power amplifiers of the wireless communication device while maintaining the total transmit power of the wireless communication device within a corresponding PSD limit.

[0144] Fig.16 1 is a flowchart illustrating an example process 1600 for supporting wireless communication with increased transmit power of a training field of a PHY preamble according to some other implementations. In some implementations, the process 1600 may be performed by a STA (such as a Figure 1 and 5B In some other implementations, the process 1600 may be performed by a wireless communication device operating as an AP (such as one of the STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0145] See for example Fig.15 , process 1600 can be a more detailed implementation of the operations for adjusting the transmit power level in block 1508 of process 1500. For example, in block 1602, process 1600 begins with the following operations: the wireless communication device adjusts the transmit power level by reducing the transmit power level by an amount that compensates for increasing the transmit power level by an additional amount over the duration of at least one LTF. In this way, a wireless communication device configured to implement one or more aspects of the subject matter disclosed herein can transmit the LTF at a higher power level than other portions of the packet without violating applicable PSD limits. The ability to increase the transmit power level of the LTF can increase the SINR of the transmitted packet, for example, to achieve better channel estimation (such as compared to transmitting the packet without increasing the transmit power level of the LTF).

[0146] Fig.17 1 is a flowchart illustrating an example process 1700 for supporting wireless communication with increased transmit power of a training field of a PHY preamble according to some other implementations. In some implementations, the process 1700 may be performed by a STA (such as a Figure 1 and 5B In some other implementations, process 1700 may be performed by a wireless communication device operating as an AP (such as one of STAs 104 or 504, respectively). Figure 1 and 5A The method may be performed by a wireless communication device operating with or within the AP (one of APs 102 or 502).

[0147] In some implementations, in block 1702, process 1700 begins by selecting an OBO value to reduce signal distortion caused by one or more power amplifiers of a wireless communication device while maintaining a total transmit power of the wireless communication device within a corresponding PSD limit.

[0148] Fig.18 1 shows a block diagram of an example wireless communication device 1800 according to some implementations. In some implementations, the wireless communication device 1800 is configured to perform the above-mentioned Fig.13A , Fig. 13B or Fig. 13C In some implementations, the wireless communication device 1800 may be any of the processes 1300, 1310, or 1320 described above. Figure 4 Example implementations of the described wireless communication device 400. For example, the wireless communication device 1800 may be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0149] The wireless communication device 1800 includes a receiving component 1810, a communication manager 1820, and a transmission component 1830. The communication manager 1820 may further include a modulation detection component 1822 and a packet format detection component 1824. Portions of one or more of the components 1822 and 1824 may be implemented at least in part in hardware or firmware. In some implementations, at least some of the components 1822 or 1824 are implemented at least in part as software stored in a memory, such as the memory 408. For example, portions of one or more of the components 1822 and 1824 may be implemented as non-transient instructions (or "code") that can be executed by a processor, such as the processor 406, to perform the functions or operations of the corresponding components.

[0150] The receiving component 1810 is configured to receive an RX signal from one or more other wireless communication devices. In some implementations, the receiving component 1810 may receive a packet or PPDU including a PHY preamble, the PHY preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet or PPDU, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0. The communication manager 1820 is configured to manage communications with other wireless communication devices. In some implementations, the modulation detection component 1822 may detect one or more modulation schemes associated with the U-SIG; and the packet format detection component 1824 may determine the format of the packet or PPDU based on the detected modulation scheme and the information in the U-SIG. The transmission component 1830 is configured to transmit a TX signal to one or more other wireless communication devices.

[0151] Fig.19 1 shows a block diagram of an example wireless communication device 1900 according to some implementations. In some implementations, the wireless communication device 1900 is configured to perform the above reference Fig.14 In some implementations, the wireless communication device 1900 may be the one described above with reference to Figure 4 Example implementations of the described wireless communication device 400. For example, the wireless communication device 1900 may be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0152] The wireless communication device 1900 includes a receiving component 1910, a communication manager 1920, and a transmission component 1930. The communication manager 1920 may further include a packet generation component 1922 and a preamble modulation component 1924. Portions of one or more of the components 1922 and 1924 may be implemented at least in part in hardware or firmware. In some implementations, at least some of the components 1922 or 1924 are implemented at least in part as software stored in a memory, such as the memory 408. For example, portions of one or more of the components 1922 and 1924 may be implemented as non-transient instructions (or "code") that can be executed by a processor, such as the processor 406, to perform the functions or operations of the corresponding components.

[0153] The receiving component 1910 is configured to receive an RX signal from one or more wireless communication devices. The communication manager 1920 is configured to manage communications with other wireless communication devices. In some implementations, the packet generation component 1922 may generate a packet or PPDU including a PHY preamble, the PHY preamble including an L-STF, an L-LTF, an L-SIG, an RL-SIG immediately following the L-SIG, and a U-SIG immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet or PPDU, wherein the L-SIG includes a length field having a value (L_LEN) satisfying L_LEN%3=0; and the preamble modulation component 1924 may modulate the first codeword of the U-SIG according to a first modulation scheme, and modulate the second codeword of the U-SIG according to a second modulation scheme different from the first modulation scheme. The transmission component 1930 is configured to transmit a TX signal to one or more other wireless communication devices. In some implementations, the transmission component 1930 may transmit a packet or PPDU on a wireless channel.

[0154] Various implementation examples are described in the following numbered clauses.

[0155] 1. A method for wireless communication by a wireless communication device, comprising:

[0156] receiving a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field having a value (L_LEN) satisfying L_LEN%3=0;

[0157] detecting one or more modulation schemes associated with a U-SIG; and

[0158] The format of the packet is determined based on the detected modulation scheme associated with the U-SIG.

[0159] 2. The method of clause 1, wherein detecting the one or more modulation schemes comprises:

[0160] determining that a first symbol of the U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme; and

[0161] It is determined that the second symbol of the U-SIG is modulated according to a Quadrature BPSK (QBPSK) modulation scheme.

[0162] 3. A method as described in any of clauses 1 or 2, wherein the determination of the format of the packet comprises:

[0163] Based on determining that the second codeword of U-SIG is modulated according to the QBPSK modulation scheme, determine that the U-SIG further includes at least a third codeword and a fourth codeword, wherein the first codeword of U-SIG carries the same decoded bits as the second codeword of U-SIG, and the third codeword of U-SIG carries the same decoded bits as the fourth codeword of U-SIG.

[0164] 4. A method as described in any of clauses 1-3, wherein each of the first codeword and the second codeword is transmitted on multiple subcarriers, and the decoded bits of the first codeword are modulated on the multiple subcarriers in a different order than the decoded bits of the second codeword.

[0165] 5. A method as described in any of clauses 1-4, wherein each of the third codeword and the fourth codeword is transmitted on multiple subcarriers, and the decoded bits of the third codeword are modulated on the multiple subcarriers in a different order than the decoded bits of the fourth codeword.

[0166] 6. The method according to any one of clauses 1 to 5, further comprising:

[0167] determining timing of a non-legacy short training field (STF) of the physical layer preamble relative to a U-SIG based on the format of the packet; and

[0168] Automatic gain control (AGC) is initiated based on the timing of the non-legacy STF.

[0169] 7. The method of any of clauses 1-6, wherein the packet comprises one or more padding symbols between a U-SIG and the non-legacy STF.

[0170] 8. The method of any of clauses 1-7, wherein determining the format of the packet comprises:

[0171] The packet is determined to conform to a non-legacy extended range (ER) packet format based on a value of a version identifier subfield of the U-SIG and a determination that the second symbol for the U-SIG is modulated according to the QBPSK modulation scheme.

[0172] 9. The method of any of clauses 1-8, wherein the preamble further comprises a non-legacy signal field immediately following the U-SIG, the non-legacy signal field comprising a single user field and one or more overflow bits from the U-SIG.

[0173] 10. The method of any of clauses 1-8, wherein the U-SIG comprises a user field carrying user-specific information for a single user, the preamble further comprising a non-legacy STF immediately following the U-SIG.

[0174] 11. A wireless communication device, comprising:

[0175] at least one modem;

[0176] at least one processor communicatively coupled to the at least one modem; and

[0177] At least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to perform the method as described in any one or more of clauses 1-10.

[0178] 12. A method for wireless communication performed by a wireless communication device, comprising:

[0179] generating a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field having a value (L_LEN) satisfying L_LEN%3=0;

[0180] modulating a first symbol of the U-SIG according to a binary phase shift keying (BPSK) modulation scheme;

[0181] modulating a second symbol of the U-SIG according to a quadrature BPSK (QBPSK) modulation scheme; and

[0182] The packet is transmitted over a wireless channel.

[0183] 13. A method as described in clause 12, wherein the U-SIG further includes at least a third codeword and a fourth codeword, the first codeword of the U-SIG carries the same decoded bits as the second codeword of the U-SIG, and the third codeword of the U-SIG carries the same decoded bits as the fourth codeword of the U-SIG.

[0184] 14. A method as described in any of clauses 12 or 13, wherein the decoded bits of the first codeword are modulated on a plurality of subcarriers in a different order than the decoded bits of the second codeword.

[0185] 15. The method of any of clauses 12-14, wherein the coded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the coded bits of the fourth symbol.

[0186] 16. The method of any of clauses 12-15, wherein the packet comprises one or more padding symbols between a U-SIG and a non-legacy short training field (STF) of the physical layer preamble.

[0187] 17. A method as recited in any of clauses 12-16, wherein the packets conform to a non-legacy extended range (ER) packet format having a bandwidth equal to 20 MHz.

[0188] 18. The method of any of clauses 12-17, wherein the preamble further comprises a non-legacy signal field immediately following the U-SIG, the non-legacy signal field comprising a single user field and one or more overflow bits from the U-SIG.

[0189] 19. The method of any of clauses 12-17, wherein the U-SIG comprises a user field carrying user-specific information for a single user, the preamble further comprising a non-legacy STF immediately following the U-SIG.

[0190] 20. A wireless communication device, comprising:

[0191] at least one modem;

[0192] at least one processor communicatively coupled to the at least one modem; and

[0193] At least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to perform the method as described in any one or more of clauses 12-19.

[0194] As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0195] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. This interchangeability of hardware, firmware, and software has been generally described in terms of their functionality and is illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0196] Various modifications to the implementations described in this disclosure may be apparent to those of ordinary skill in the art, and the universal principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but should be granted the widest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0197] In addition, various features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable subcombination. Thus, while features may be described above as functioning in a particular combination and even initially claimed as such, one or more features from a claimed combination may in some cases be removed from the combination, and a claimed combination may be directed to a subcombination, or a variation of a subcombination.

[0198] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the particular order shown or in a sequential order, or to perform all the illustrated operations to achieve the desired result. In addition, the accompanying drawings may schematically depict one or more example processes in the form of a flow chart or a flow diagram. However, other operations that are not depicted may be incorporated into the example processes schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously or between any illustrated operations. In some environments, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the implementation described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A method for wireless communication by a wireless communication device, comprising: receiving a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field (L_LEN) having a value satisfying L_LEN modulo 3 equal to 0; detecting a plurality of modulation schemes applied to a U-SIG, wherein a first symbol of the U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes, and a second symbol of the U-SIG is modulated according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes; as well as The second symbol of the U-SIG is determined to be a repetition of the first symbol of the U-SIG based on the first symbol being modulated according to the BPSK modulation scheme and the second symbol being modulated according to the QBPSK modulation scheme.

2. The method of claim 1, further comprising: Based on determining that the second codeword of U-SIG is modulated according to the QBPSK modulation scheme, it is determined that the U-SIG further includes at least a third codeword and a fourth codeword, the first codeword of U-SIG carries the same first decoded bit as the second decoded bit carried by the second codeword of U-SIG, and the third codeword of U-SIG carries the same third decoded bit as the fourth decoded bit carried by the fourth codeword of U-SIG.

3. The method of claim 2, wherein each of the first symbol and the second symbol is transmitted on multiple subcarriers, the first decoded bits of the first symbol being modulated on the multiple subcarriers in a different order than the second symbol.

4. The method of claim 2, wherein each of the third symbol and the fourth symbol is transmitted on a plurality of subcarriers, the third coded bits of the third symbol being modulated on the plurality of subcarriers in a different order than the fourth symbol.

5. The method of claim 1, further comprising: determining timing of a non-legacy short training field (STF) of the physical layer preamble relative to a U-SIG based on the second symbol being a repetition of the first symbol; as well as Automatic gain control (AGC) is initiated based on the timing of the non-legacy STF.

6. The method of claim 5, wherein the packet includes one or more padding symbols between a U-SIG and the non-legacy STF.

7. The method of claim 1, further comprising: The packet is determined to comply with a non-legacy extended range (ER) packet format based on a value of a version identifier subfield of the U-SIG and that the second symbol of the U-SIG is modulated according to the QBPSK modulation scheme.

8. The method of claim 7, wherein the physical layer preamble further comprises a non-legacy signal field following the U-SIG, the non-legacy signal field comprising a single user field and one or more overflow bits from the U-SIG.

9. The method of claim 7, wherein the U-SIG includes a user field carrying user-specific information for a single user, and the physical layer preamble further includes a non-legacy STF following the U-SIG.

10. A wireless communication device, comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: receiving a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field (L_LEN) having a value satisfying L_LEN modulo 3 equal to 0; detecting a plurality of modulation schemes applied to a U-SIG, wherein a first symbol of the U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes, and a second symbol of the U-SIG is modulated according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes; as well as The second symbol of the U-SIG is determined to be a repetition of the first symbol of the U-SIG based on the first symbol being modulated according to the BPSK modulation scheme and the second symbol being modulated according to the QBPSK modulation scheme.

11. The wireless communication device of claim 10, wherein execution of the processor readable code is further configured to: Based on determining that the second codeword of U-SIG is modulated according to the QBPSK modulation scheme, it is determined that the U-SIG further includes at least a third codeword and a fourth codeword, the first codeword of U-SIG carries the same first decoded bit as the second decoded bit carried by the second codeword of U-SIG, and the third codeword of U-SIG carries the same third decoded bit as the fourth decoded bit carried by the fourth codeword of U-SIG.

12. The wireless communication device of claim 11, wherein the first decoded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol, and the third decoded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the fourth symbol.

13. The wireless communication device of claim 11, wherein execution of the processor readable code is further configured to: determining timing of a non-legacy short training field (STF) of the physical layer preamble relative to a U-SIG based on the second symbol being a repetition of the first symbol; and Automatic gain control (AGC) is initiated based on the timing of the non-legacy STF.

14. The wireless communication device of claim 13, wherein the packet comprises one or more padding symbols between a U-SIG and the non-legacy STF.

15. A method for wireless communication by a wireless communication device, comprising: generating a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field (L_LEN) having a value satisfying L_LEN modulo 3 equal to 0; selecting a plurality of modulation schemes to be applied to the U-SIG to indicate the presence of repetitions of one or more symbols of the U-SIG; modulating a first symbol of the one or more symbols of the U-SIG according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes; modulating the second symbol according to a quadrature BPSK (QBPSK) modulation scheme from among the plurality of modulation schemes based at least in part on the second symbol of the U-SIG being a repetition of the first symbol; as well as The packet is transmitted over a wireless channel.

16. The method of claim 15 , wherein the U-SIG further comprises at least a third symbol and a fourth symbol of the one or more symbols, the first symbol of the U-SIG carrying a first decoded bit identical to a second decoded bit carried by the second symbol of the U-SIG, and the third symbol of the U-SIG carrying a third decoded bit identical to a fourth decoded bit carried by the fourth symbol of the U-SIG.

17. The method of claim 16, wherein the first decoded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol.

18. The method of claim 16, wherein third decoded bits of the third symbol are modulated on a plurality of subcarriers in a different order than the fourth symbol.

19. The method of claim 16, wherein the packet includes one or more padding symbols between a U-SIG and a non-legacy short training field (STF) of the physical layer preamble.

20. The method of claim 16, wherein the packet complies with a non-legacy extended range (ER) packet format having a bandwidth equal to 20 MHz.

21. The method of claim 20, wherein the physical layer preamble further comprises a non-legacy signal field immediately following the U-SIG, the non-legacy signal field comprising a single user field and one or more overflow bits from the U-SIG.

22. The method of claim 20, wherein the U-SIG includes a user field carrying user-specific information for a single user, the physical layer preamble further including a non-legacy STF immediately following the U-SIG.

23. A wireless communication device, comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: generating a packet including a physical layer preamble, the physical layer preamble including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repetition of the L-SIG (RL-SIG) immediately following the L-SIG, and a universal signal field (U-SIG) immediately following the RL-SIG and including information for interpreting one or more subsequent fields of the packet, the L-SIG including a length field (L_LEN) having a value satisfying L_LEN modulo 3 equal to 0; selecting a plurality of modulation schemes to be applied to the U-SIG to indicate the presence of repetitions of one or more symbols of the U-SIG; modulating a first symbol of the one or more symbols of the U-SIG according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes; modulating a second symbol of the U-SIG according to a quadrature BPSK (QBPSK) modulation scheme from among the plurality of modulation schemes based at least in part on the second symbol of the U-SIG being a repetition of the first symbol; as well as The packet is transmitted over a wireless channel.

24. The wireless communication device of claim 23, wherein the U-SIG further comprises at least a third symbol and a fourth symbol of the one or more symbols, the first symbol of the U-SIG carrying a first decoded bit identical to a second decoded bit carried by the second symbol of the U-SIG, and the third symbol of the U-SIG carrying a third decoded bit identical to a fourth decoded bit carried by the fourth symbol of the U-SIG.

25. The wireless communication device of claim 24, wherein the first decoded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol, and the third decoded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the fourth symbol.

26. The wireless communication device of claim 23, wherein the packet complies with a non-legacy extended range (ER) packet format having a bandwidth equal to 20 MHz.

27. The wireless communication device of claim 26, wherein the physical layer preamble further comprises a non-legacy signal field following the U-SIG, the non-legacy signal field comprising a single user field and one or more overflow bits from the U-SIG.

28. The wireless communication device of claim 26, wherein the U-SIG includes a user field that carries user-specific information for a single user, the physical layer preamble further comprising a non-legacy STF following the U-SIG.

Images