Global Cyclic Shift Delay for Distributed Transmission

Abstract

The present disclosure provides methods, devices, and systems for increasing the transmission power of a wireless communication device operating on a power spectral density (PSD) limited wireless channel. Some implementations relate more specifically to short training field (STF) design and signaling to support distributed transmission. A transmitting device transmitting data on a distributed resource unit (dRU) can transmit an STF sequence over the spreading bandwidth of the dRU according to an existing STF tone plan. Each STA allocated a dRU for transmission in a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) can map its STF sequence to one or more spatial streams and apply one or more global cyclic shift delays (CSDs) to the STF sequences mapped to the one or more spatial streams, respectively. Thus, different global CSDs may be assigned to different STAs such that each STA transmits its STF sequence with a different amount of delay.

Description

[Technical field]

[0001] cross reference This patent application claims the benefit of U.S. patent application Ser. No. 17 / 503,215 by YANG et al., entitled “GLOBAL CYCLIC SHIFT DELAYS FOR DISTRIBUTED TRANSMISSION,” filed Oct. 15, 2021, which is assigned to the assignee of this application and is expressly incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to wireless communications, and more particularly, to global cyclic shift delays (CSD) for distributed transmission. [Background technology]

[0003] 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 called stations (STAs). The basic building block of a WLAN conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family is the Basic Service Set (BSS) managed by the AP. Each BSS is identified by a Basic Service Set Identifier (BSSID) advertised by the AP. The AP periodically broadcasts beacon frames to enable any STA within wireless range of the AP to establish or maintain a communication link with the WLAN.

[0004] In some cases, APs and STAs may be subject to power spectral density (PSD) limitations. For example, some APs and STAs operating in the 6 gigahertz (GHz) frequency band may need to comply with a low power indoor (LPI) power class that limits the transmit power of APs and STAs (in the 6 GHz band) to 5 decibel-milliwatts per megahertz (dBm / MHz) and -1 dBm / MHz, respectively. In other words, transmit power in the 6 GHz band is PSD limited per MHz. Such PSD limitations may undesirably reduce the range of wireless communications and may reduce the packet detection and channel estimation capabilities of APs and STAs. Summary of the Invention

[0005] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single aspect of which is solely responsible for the desirable properties disclosed herein.

[0006] One innovative aspect of the subject matter described in this disclosure may be realized as a method of wireless communication. The method may be performed by a wireless communication device and may include obtaining data for transmission in a physical layer convergence protocol (PLCP) protocol data unit (PPDU), modulating data on M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across a wireless channel according to a distributed tone plan, the M tones mapped to the M non-contiguous subcarrier indexes representing distributed resource units (dRUs) assigned to the wireless communication device, obtaining a first sequence of values ​​representing a short training field (STF) of the PPDU based on a bandwidth associated with the wireless channel, mapping the data and the first sequence of values ​​to one or more spatial streams, and applying one or more first cyclic shift delays based on the dRU assignment. applying a time-domain delay (CSD) to the first sequence of values ​​mapped to the one or more spatial streams, respectively; and transmitting, via a wireless channel, a PPDU including the first sequence of values ​​mapped to the one or more spatial streams. may include.

[0007] In some aspects, the method may further include obtaining a second sequence of values ​​representing a long training field (LTF) of the PPDU, mapping the second sequence of values ​​to one or more spatial streams, and applying one or more first CSDs to the data mapped to the one or more spatial streams and the sequence of second values, respectively. In some other aspects, the method may further include obtaining a second sequence of values ​​representing an LTF of the PPDU, mapping the second sequence of values ​​to one or more spatial streams, and applying one or more second CSDs to the data mapped to the one or more spatial streams and the sequence of second values, respectively, where the one or more second CSDs are different from the one or more first CSDs.

[0008] In some aspects, the method may further include generating the one or more first CSDs as a function of an association identifier (AID) value assigned to the wireless communication device. (In some other aspects, the method may further include obtaining the one or more first CSDs from a CSD table having a number (N) of entries, each indicating a respective CSD associated with the distributed tone plan. In some implementations, N may be equal to 8 or 16. In some aspects, obtaining the one or more first CSDs may include calculating a starting index associated with the one or more first CSDs based on information assigned to the wireless communication device, the starting index pointing to one of the N entries of the CSD table. In some implementations, the information assigned to the wireless communication device may include at least one of an AID value, a resource unit (RU) allocation index associated with the dRU, or a starting tone offset associated with the dRU. In some implementations, the starting index may be calculated as a modulo operation of the information assigned to the wireless communication device and N.

[0009] In some other aspects, obtaining the one or more first CSDs may include receiving a trigger frame requesting a PPDU from the wireless communication device, the trigger frame carrying CSD information indicating a starting index associated with the one or more first CSDs, the starting index pointing to one of the N entries of the CSD table. In some implementations, the CSD information may be carried in a user information field associated with the wireless communication device. In some aspects, the trigger frame may further carry distributed transmission information indicating that the data is to be transmitted according to a distributed tone plan and may carry dRU distributed bandwidth information indicating a bandwidth associated with the wireless channel. In some implementations, the distributed transmission information and the dRU distributed bandwidth information may be carried in a user information field associated with the wireless communication device. In some other implementations, the distributed transmission information may be carried in a common information field or a specific user information field immediately following the common information field, and the dRU distributed bandwidth information may be carried in a user information field associated with the wireless communication device.

[0010] Another innovative aspect of the subject matter described in this disclosure may be implemented in a wireless communication device. In some implementations, the wireless communication device may include at least one processor 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 includes, to a wireless communication device, obtaining data for transmission in a PPDU; modulating data on M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to a distributed tone plan, where the M tones mapped to the M non-contiguous subcarrier indexes represent dRUs assigned to the wireless communication device; obtaining a first sequence of values ​​representing an STF of the PPDU based on a bandwidth associated with the wireless channel; mapping the data and the first sequence of values ​​to one or more spatial streams; applying one or more first CSDs to the first sequence of values ​​mapped to the one or more spatial streams, respectively, based on the dRU assignments; and transmitting a PPDU over the wireless channel including the first sequence of values ​​mapped to the one or more spatial streams. The method includes the steps of:

[0011] Another innovative aspect of the subject matter described in this disclosure may be realized as a method of wireless communication. The method may be performed by a wireless communication device and may include transmitting a trigger frame requesting a trigger-based (TB) PPDU from one or more wireless stations (STAs), the trigger frame carrying first distributed transmission information indicating that a first data portion of the TB PPDU is to be transmitted according to a distributed tone plan and further carrying first dRU distributed bandwidth information indicating a bandwidth of a wireless channel allocated for transmission of the first data portion, receiving a TB PPDU from the one or more STAs in response to the trigger frame, and recovering the first data portion of the TB PPDU from M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to the distributed tone plan.

[0012] In some implementations, the first distributed transmission information and the first dRU distributed bandwidth information may be carried in a user information field associated with a first STA of the one or more STAs. In some other implementations, the first distributed transmission information may be carried in a common information field or a specific user information field immediately following the common information field, and the first dRU distributed bandwidth information may be carried in a user information field associated with the first STA of the one or more STAs.

[0013] In some implementations, the trigger frame may further carry second distributed transmission information indicating that the second data portion of the TB PPDU is to be transmitted according to a distributed tone plan and may carry second dRU distributed bandwidth information indicating that the bandwidth of the wireless channel is allocated for transmission of the second data portion. In some implementations, the first data portion may be received on one or more first spatial streams and the second data portion may be received on one or more second spatial streams, and the TB PPDU further includes an STF carrying a sequence of first values ​​being received on each of the one or more first spatial streams and each of the one or more second spatial streams.

[0014] In some aspects, the sequence of first values ​​received on one or more first spatial streams may be delayed by one or more first CSDs, respectively, and the sequence of first values ​​received on one or more second spatial streams may be delayed by one or more second CSDs, respectively. In some implementations, the trigger frame may further carry first CSD information indicating a first starting index associated with one or more first CSDs, and may carry second CSD information indicating a second starting index associated with one or more second CSDs, where the first starting index points to a first entry of a CSD table having a number (N) of entries each indicating a respective CSD associated with the distributed tone plan, and the second starting index points to a second entry of the CSD table that is different from the first entry. In some implementations, N may be equal to 8 or 16. In some implementations, the first CSD information may be carried in a user information field associated with a first STA of the one or more STAs, and the second CSD information may be carried in a user information field associated with a second STA of the one or more STAs.

[0015] In some implementations, the TB PPDU may further include an LTF carrying a sequence of second values ​​received on each of the one or more first spatial streams and a sequence of third values ​​received on each of the one or more second spatial streams, where the first data portion and the sequence of second values ​​received on the one or more first spatial streams are delayed by one or more first CSDs, respectively, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are delayed by one or more second CSDs, respectively.

[0016] In some other implementations, the TB PPDU may further include an LTF carrying a sequence of second values ​​being received on each of the one or more first spatial streams and a sequence of third values ​​being received on each of the one or more second spatial streams, where the first data portion and the sequence of second values ​​received on the one or more first spatial streams are each delayed by one or more third CSDs different from the one or more first CSDs, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are each delayed by one or more fourth CSDs different from the one or more second CSDs.

[0017] Another innovative aspect of the subject matter described in this disclosure may be executed in a wireless communication device. In some implementations, the wireless communication device may include at least one processor 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 may include transmitting, to the wireless communication device, a trigger frame requesting a TB PPDU from one or more STAs, the trigger frame carrying first distributed transmission information indicating that a first data portion of the TB PPDU will be transmitted according to a distributed tone plan and further carrying first dRU distributed bandwidth information indicating a bandwidth of a wireless channel allocated for transmission of the first data portion, receiving the TB PPDU from the one or more STAs in response to the trigger frame, and recovering the first data portion of the TB PPDU from M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to the distributed tone plan.

[0018] The details of one or more implementations of the subject matter described in this 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 dimensions of the following figures may not be drawn to scale. [Brief description of the drawings]

[0019] [Figure 1] 1 shows a pictorial diagram of an exemplary wireless communication network. [Figure 2A] 1 illustrates an exemplary protocol data unit (PDU) that may be used for communication between an access point (AP) and one or more wireless stations (STAs). [Figure 2B] 2B illustrates exemplary fields within the PDU of FIG. 2A. [Diagram 3]1 illustrates an example Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) that may be used for communication between an AP and one or more STAs. [Figure 4] 1 illustrates a block diagram of an exemplary wireless communication device. [Figure 5A] 1 shows a block diagram of an exemplary AP. [Figure 5B] 1 shows a block diagram of an exemplary STA. [Figure 6] 1 shows a frequency diagram illustrating an example distributed tone mapping according to some implementations. [Figure 7] FIG. 1 illustrates a frequency diagram illustrating an example mapping of logical resource units (RUs) to distributed RUs (dRUs) according to some implementations. [Figure 8] 1 illustrates an example PPDU that may be used for communication between an AP and one or more STAs, according to some implementations. [Figure 9] 1 shows a frequency diagram illustrating an example short training field (STF) sequence that can be used for automatic gain control (AGC) in distributed transmission. [Figure 10] 1 illustrates an example frame structure of a trigger-based (TB) PPDU according to some implementations. [Figure 11] 1 illustrates a block diagram of an example transmit (TX) processing chain of a wireless communication device, according to some implementations. [Figure 12] 1 illustrates an example trigger frame that may be used for communication between an AP and one or more STAs, according to some implementations. [Figure 13] 1 shows the user information field of a trigger frame formatted according to an existing trigger frame format. [Figure 14] 1 illustrates another example trigger frame that may be used for communication between an AP and one or more STAs, according to some implementations. [Figure 15]1 shows the common information field of a trigger frame formatted according to an existing trigger frame format. [Figure 16] 1 shows a special user information field of a trigger frame formatted according to an existing trigger frame format. [Figure 17] 1 illustrates another example trigger frame that may be used for communication between an AP and one or more STAs, according to some implementations. [Figure 18] 1 shows a flowchart illustrating an example process for wireless communication supporting global cyclic shift delay (CSD) for distributed transmission. [Figure 19] 1 shows a flowchart illustrating an example process for wireless communication supporting global CSD with distributed transmission. [Figure 20] 1 shows a block diagram of an example wireless communication device according to some implementations. [Figure 21] 1 shows a block diagram of an example wireless communication device according to some implementations.

[0020] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The following description is directed to several implementations for the purpose of describing the innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be realized in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth standard defined by the Bluetooth Special Interest Group (SIG), or the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), among others. The described implementations may be realized in any device, system, or network capable of transmitting and receiving RF signals according to 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 realized using other wireless communications 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.

[0022] The term "distributed transmission" as used herein refers to the transmission of a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) on non-contiguous tones (or subcarriers) of a wireless channel (e.g., according to a "distributed tone plan"). Such non-contiguous tones represent a "distributed" resource unit (dRU). In contrast, a "regular" resource unit (rRU) is any set of contiguous tones defined by existing versions of the IEEE 802.11 standard (also called a "non-distributed tone plan"). Distributed transmission provides greater flexibility in medium utilization for power spectral density (PSD) limited wireless channels. As explained above, the low power indoor (LPI) power class limits the transmit power of APs and STAs to 5 dBm / MHz and -1 dBm / MHz, respectively, in the 6 GHz band. By allowing a wireless communication device to distribute the tones allocated for the transmission of a PPDU across non-contiguous subcarrier indexes of a wireless channel, distributed transmission may increase the overall transmit power of the PPDU without exceeding the PSD limit of the wireless channel. For example, a distributed tone plan may reduce the total number of tones modulated by a device on any 1 MHz subchannel of a wireless channel. As a result, a wireless communication device may increase its per-tone transmit power without exceeding the PSD limit.

[0023] The IEEE 802.11 standard defines a PPDU format to be used for wireless communication, including one or more Short Training Fields (STFs). The STF is generally used for automatic gain control (AGC) and carrier frequency (DC) estimation at a receiving device. For example, a transmitting device may transmit a known pattern of symbols within the STF to a receiving device. The receiving device may use its knowledge of the symbol pattern and its periodicity within the received STF (also referred to as an "STF sequence") to estimate the power of the received signal and perform DC estimation. Furthermore, the receiving device may dynamically adjust its amplifier gain based on the estimated power of the STF to correct the DC of the received signal to ensure more accurate reception of the data portion of the PPDU. Existing versions of the IEEE 802.11 standard define various STF sequences and tone plans (also referred to as "existing STF tone plans") associated with various PPDU formats and bandwidths. According to existing versions of the IEEE 802.11 standard, rRUs transmit over respective bandwidths (or sub-bands) exclusively allocated for the rRUs, and the STF associated with each rRU is transmitted over the STF tones in that rRU. However, in distributed transmission, multiple dRUs may transmit on interleaved tones of a shared bandwidth (also called "spread bandwidth" or "distributed bandwidth"). Because the STF is used to estimate the signal power of the modulated tones, changing the tone plan used for PPDU transmission (such as from a non-distributed tone plan to a distributed tone plan) may require new dRU-related signaling and STF design.

[0024] Various aspects relate generally to distributed transmissions, and more particularly, to STF design and signaling to support distributed transmissions. In some aspects, a transmitting device may transmit data on a dRU and may transmit an STF sequence over the spreading bandwidth of the dRU according to an existing STF tone plan. Thus, in a trigger-based (TB) PPDU, wireless stations (STAs) that are assigned a dRU within the same spreading bandwidth may transmit the same STF sequence on the same set of tones. In some implementations, each STA that is allocated a dRU for transmission in a TB PPDU may map its STF sequence to one or more spatial streams and may apply one or more global cyclic shift delays (CSDs) to the STF sequences mapped to the one or more spatial streams, respectively. As used herein, the term "global CSD" refers to a CSD assignment that takes into account the position of each STA associated with the PPDU. For example, different global CSDs may be assigned to different STAs such that each STA transmits its STF sequence with a different amount of delay. In some implementations, each STA may randomly generate its global CSD value. In some other implementations, each STA may select its global CSD value from a CSD table based on information assigned to the STA (such as an association identifier (AID) value or an RU index, an RU allocation index, or a starting tone offset associated with the dRU). Still further, in some implementations, each STA may receive an indication of its global CSD index or value in a trigger frame requesting a TB PPDU. In some aspects, the trigger frame may carry distributed transmission information indicating which STAs have been allocated dRUs for transmission in the TB PPDU and may carry dRU distributed bandwidth information indicating the spreading bandwidth associated with the dRU.

[0025] Particular implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages: As described above, transmitting the data portion of the PPDU on discontinuous tones of a wireless channel allows a transmitting device to increase the overall transmit power of the data without exceeding the PSD limit of the wireless channel. Transmitting the STF of the PPDU over the spreading bandwidth of the dRU allows a receiving device to more accurately estimate the power of the received signal associated with the data portion. By reusing the existing STF tone plan, aspects of the present disclosure may support AGC for distributed transmissions with minor modifications to the IEEE 802.11 standard. However, aspects of the present disclosure recognize that unintended beamforming may result from multiple STAs simultaneously transmitting the same STF sequence on the same set of tones (such as in a TB PPDU). For example, such superimposed STF transmissions may constructively or destructively interfere at a receiving device, causing the receiving device to obtain inaccurate power measurements for the received signal. By applying a global CSD to the STF sequences transmitted by each STA on each spatial stream, aspects of the present disclosure may separate STF transmissions from multiple STAs in the time domain. More specifically, the global CSD may stagger the phase of STF transmissions across different STAs and different spatial streams, thereby preventing or reducing unintended beamforming at a receiving device.

[0026] FIG. 1 illustrates a block diagram of an exemplary wireless communication network 100. 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 hereinafter referred to as WLAN 100). For example, the WLAN 100 may be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards (as defined by the IEEE 802.11-2020 specification or amendments thereof, 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 multiple wireless communication devices, such as an access point (AP) 102 and multiple stations (STAs) 104. Although only one AP 102 is shown, the WLAN network 100 may include multiple APs 102.

[0027] Each of the STAs 104 may also be referred to as a mobile station (MS), mobile device, mobile handset, wireless handset, access terminal (AT), user equipment (UE), subscriber station (SS), or subscriber unit, among other possible examples. The STAs 104 may represent a variety of devices, such as a mobile phone, a personal digital assistant (PDA), other handheld device, a netbook, a notebook computer, a tablet computer, a laptop, a display device (e.g., a TV, a computer monitor, a navigation system, among others), a music or other audio or stereo device, a remote control device ("remote"), a printer, a kitchen appliance or other household appliance, a key fob (e.g., for a passive keyless entry and start (PKES) system), among other possible examples.

[0028] A single AP 102 and the associated set of STAs 104 may be referred to as a basic service set (BSS) managed by each AP 102. FIG. 1 additionally illustrates an example coverage area 108 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 to other devices by a basic service set identifier (BSSID), which may be the medium access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame ("beacon") containing the BSSID to allow any STAs 104 within wireless range of the AP 102 to "associate" or reassociate with the AP 102 to establish a respective communication link 106 (hereinafter also referred to as a "Wi-Fi link") with the AP 102 or to maintain a communication link 106 with the AP 102. For example, the beacon may include an identification of the primary channel used by each AP 102, as well as a timing synchronization function to establish or maintain timing synchronization with the AP 102. The APs 102 may provide access to external networks to various STAs 104 in the WLAN via respective communication links 106.

[0029] To establish a communication link 106 with an AP 102, each of the STAs 104 is configured to perform passive or active scanning operations ("scans") on frequency channels within one or more frequency bands (e.g., the 2.4 GHz, 5 GHz, 6 GHz, or 60 GHz bands). To perform passive scanning, the STAs 104 listen for beacons transmitted by the respective APs 102 at regular time intervals called target beacon transmission times (TBTTs) (measured in time units (TUs), where one TU may equal 1024 microseconds (μs)). To perform active scanning, the STAs 104 generate probe requests and transmit them continuously on each channel to be scanned, and listen for probe responses from the APs 102. Each STA 104 may be configured to perform an authentication and association operation to identify or select an AP 102 to associate with based on scan information obtained through passive or active scanning, and establish a communication link 106 with the selected AP 102. Upon completing the association operation, the AP 102 assigns an association identifier (AID) to the STA 104, which the AP 102 uses to track the STA 104.

[0030] As a result of the increasing ubiquity of wireless networks, a STA 104 may have the opportunity to select one of many BSSs within range of the STA, or among multiple APs 102 that together form an extended service set (ESS) that includes multiple connected BSSs. The extended network stations associated with the WLAN 100 may be connected to a wired or wireless distribution system that may allow multiple APs 102 to be connected in such an ESS. Thus, a STA 104 may be covered by more than one AP 102 and may associate with different APs 102 at different times for different transmissions. Additionally, after association with an AP 102, the STA 104 may also be configured to periodically scan its surroundings to find a more suitable AP 102 to associate with. For example, a STA 104 moving with respect to its associated AP 102 may perform a "roaming" scan to find another AP 102 with more desirable network characteristics, such as a greater received signal strength indicator (RSSI) or reduced traffic load.

[0031] In some cases, the STAs 104 may form a network without involving the AP 102 or other devices other than the STAs 104 themselves. One example of such a network is an ad-hoc network (or wireless ad-hoc network). An ad-hoc network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, the ad-hoc network may be implemented within a larger wireless network, such as the WLAN 100. In such an implementation, the STAs 104 may be able to communicate with each other via the AP 102 using the communication link 106, but the STAs 104 may also communicate with each other directly via a direct wireless link 110. In addition, two STAs 104 may communicate via the direct communication link 110 regardless of whether both STAs 104 are associated with and served by the same AP 102. In such an ad-hoc system, one or more of the STAs 104 may assume the role filled by the AP 102 in the BSS. Such STAs 104 may be referred to as group owners (GOs) and may coordinate transmissions within the ad-hoc network. Examples of direct wireless links 110 include Wi-Fi direct connections, connections established by using Wi-Fi Tunneled Direct Link Setup (TDLS) links, and other P2P group connections.

[0032] The AP 102 and the STAs 104 may function and communicate (via their respective communication links 106) according to the IEEE 802.11 family of wireless communication protocol standards (as defined by the IEEE 802.11-2016 specification or amendments thereof, 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 layer and medium access control (MAC) layer. The AP 102 and the STAs 104 transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") between each other in the form of Physical Layer Convergence Protocol (PLCP) Protocol Data Units (PPDUs). The AP 102 and the STAs 104 in the WLAN 100 may transmit PPDUs over 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 the STAs 104 described herein may also communicate in other frequency bands, such as the 6 GHz band, which may support both licensed and unlicensed communications. The AP 102 and the STAs 104 may also be configured to communicate over other frequency bands, such as shared licensed frequency bands, in which multiple operators may have licenses to operate in the same or overlapping frequency bands.

[0033] Each of the frequency bands may include multiple sub-bands or frequency channels. For example, PPDUs conforming to IEEE 802.11n, 802.11ac, 802.11ax, and 802.11be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, or 6 GHz bands, each of which is divided into multiple 20 MHz channels. Thus, these PPDUs are transmitted over physical channels with a minimum bandwidth of 20 MHz, but larger channels may be formed through channel bonding. For example, PPDUs may be transmitted over physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0034] Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PHY service data unit (PSDU). Information provided in the preamble may be used by a receiving device to decode subsequent data in the PSDU. In instances where a PPDU is transmitted over bonded channels, the preamble field may be replicated and transmitted in each of the multiple constituent channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble may be used for packet detection, automatic gain control, and channel estimation, among other applications. The legacy preamble may also generally be used to maintain compatibility with legacy devices. The format, coding, and information provided therein of the non-legacy portion of the preamble is based on the particular IEEE 802.11 protocol that will be used to transmit the payload.

[0035] 2A illustrates an exemplary protocol data unit (PDU) 200 usable for wireless communication between an AP 102 and one or more STAs 104. 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, which may consist of two BPSK symbols, a legacy long training field (L-LTF) 208, which may consist of two BPSK symbols, and a legacy signal field (L-SIG) 210, which 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 that includes one or more non-legacy fields 212 that conform to an IEEE wireless communication protocol, such as, for example, an IEEE 802.11ac, 802.11ax, 802.11be, or later wireless communication protocol standard.

[0036] The L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. The L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and also enables the receiving device to perform an initial estimation of the wireless channel. The L-SIG 210 generally enables the receiving device to determine the duration of a PDU and use the determined duration to avoid transmitting over the PDU. For example, the L-STF 206, the L-LTF 208, and the L-SIG 210 may be modulated according to a binary phase shift keying (BPSK) modulation scheme. The payload 204 may be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another suitable modulation scheme. The payload 204 may include a PSDU that includes a data field (DATA) 214, which may carry higher layer data, for example in the form of a Medium Access Control (MAC) Protocol Data Unit (MPDU) or an Aggregated MPDU (A-MPDU).

[0037] 2B illustrates an example L-SIG 210 in the PDU 200 of FIG. 2A. The L-SIG 210 includes a data rate field 222, a reserved bit 224, a length field 226, a parity bit 228, and a tail field 230. The data rate field 222 indicates a 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 length of the packet, e.g., in units of symbols or bytes. The parity bit 228 may be used to detect bit errors. The tail field 230 includes tail bits that 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 duration of the packet, e.g., in units of microseconds (μs) or other time units.

[0038] 3 illustrates an exemplary PPDU 300 that may be used for communication between an AP 102 and one or more STAs 104. As discussed 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 aggregate 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 prior to an associated MPDU 316 that comprises a data portion ("payload" or "frame body") of the MPDU frame 310. Each MPDU frame 310 may 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) 326. For example, the MPDU 316 may carry an aggregate MSDU (A-MSDU) 322 that includes multiple A-MSDU subframes 324. Each A-MSDU subframe 324 includes a corresponding MSDU 330 preceded by a subframe header 328 and possibly followed by padding bits 332.

[0039] Referring again to the MPDU frame 310, the MAC delimiter 312 serves as a marker of the start of the associated MPDU 316 and may indicate the length of the associated MPDU 316. The MAC header 314 may include multiple fields containing information that defines or indicates characteristics or attributes of the data encapsulated within the frame body 316. The MAC header 314 includes a duration field that indicates a duration that lasts 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 helps to reserve the wireless medium for the indicated duration, allowing the receiving device to establish its network allocation vector (NAV). The MAC header 314 also includes one or more fields that indicate 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 that includes control information. The frame control field may specify the frame type, for example, a data frame, a control frame, or a management frame.

[0040] 4 shows a block diagram of an example wireless communication device 400. In some implementations, the wireless communication device 400 may be an example of a device for use in a STA, such as one of the STAs 104 described with reference to FIG 1. In some implementations, the wireless communication device 400 may be an example of a device for use in an AP, such as the AP 102 described with reference to FIG 1. 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, a wireless communication device may be configured to transmit and receive packets in the form of Physical Layer Convergence Protocol (PLCP) Protocol Data Units (PPDUs) and Medium Access Control (MAC) Protocol Data Units (MPDUs) that conform to IEEE 802.11 wireless communications protocol standards as defined by the IEEE 802.11-2016 specification or amendments thereof, including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be.

[0041] The wireless communication device 400 may be or include a chip, system on chip (SoC), chipset, package, or device including one or more modems 402, such as a Wi-Fi (IEEE 802.11 compliant) modem. In some implementations, the one or more modems 402 (collectively "modems 402") additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compliant 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 elements 406 (collectively "processors 406") and one or more memory blocks or elements 408 (collectively "memory 408").

[0042] The modem 402 may include an intelligent hardware block or device, such as, for example, an application-specific integrated circuit (ASIC), among other possible examples. The modem 402 is generally configured to implement a PHY layer. For example, the modem 402 is configured to modulate packets and output the modulated packets to the radio 404 for transmission over a wireless medium. The modem 402 is also 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 digital signal processing (DSP) circuitry, an automatic gain control (AGC), a coder, a decoder, a multiplexer, and a demultiplexer. For example, while in a transmit mode, data obtained from the processor 406 is provided to a coder, which encodes the data to provide coded bits. The coded bits are then mapped to points in a modulation constellation (using a selected MCS) to provide modulated symbols. The modulated symbols are then N SS number of spatial streams or N STS The modulated symbols in each spatial or space-time stream may then be multiplexed and converted via an inverse fast Fourier transform (IFFT) block, followed by providing to a DSP circuit 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 a frequency up-converter and ultimately to the radio 404. In an implementation involving beamforming, the modulated symbols in each spatial stream are precoded via a steering matrix prior to their provision to the IFFT block.

[0043] While in the receive mode, the digital signal received from the radio 404 is provided to the DSP circuit, which is configured to acquire the received signal, for example, by detecting the presence of a signal and estimating an initial timing and frequency offset. The DSP circuit is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment adjustment (such as correcting I / Q imbalance), and finally applying a digital gain to obtain a narrowband signal. The output of the DSP circuit may then be provided to an AGC, which is configured to use information extracted from the digital signal in one or more received training fields, for example, to determine an appropriate gain. The output of the DSP circuit is also coupled to a demodulator, which is configured to extract modulated symbols from the signal and calculate, for example, logarithm likelihood ratios (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder, which may be configured to process the LLR to provide decoded bits. The decoded bits from all of the spatial streams are then provided to a demultiplexer for demultiplexing, which may then be descrambled and provided to the MAC layer (processor 406) for processing, evaluation, or interpretation.

[0044] 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 RF receiver may each include various DSP circuits, including at least one power amplifier (PA) and at least one low-noise amplifier (LNA). The RF transmitter and RF receiver may then 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 with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). Symbols output from the modem 402 are provided to the radio 404, which then transmits the symbols via the coupled antenna. Similarly, symbols received via the antennas are obtained by the radio 404, which then provides the symbols to the modem 402.

[0045] The processor 406 may include intelligent hardware blocks or devices, such as, for example, a processing core, processing block, central processing unit (CPU), microprocessor, microcontroller, digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic device (PLD) such as field programmable gate array (FPGA), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor 406 processes information received via the radio 404 and modem 402, and processes information to be output via the modem 402 and radio 404 for transmission over a wireless medium. For example, the processor 406 may implement a control plane and MAC layer 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 frame coding and decoding, spatial multiplexing, space-time block coding (STBC), beamforming, and OFDMA resource allocation, among other operations or techniques. In some implementations, the processor 406 may generally control the modem 402 to cause the modem to perform various operations described above.

[0046] 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-transitory processor or computer-executable software (SW) code that includes instructions that, when executed by the processor 406, cause the processor to perform various operations described herein for wireless communication, including generating, transmitting, receiving, and interpreting MPDUs, frames, or packets. For example, various functions of the components disclosed herein, or 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.

[0047] FIG. 5A illustrates a block diagram of an exemplary AP 502. For example, the AP 502 may be an exemplary implementation of the AP 102 described with reference to FIG. 1. The AP 502 includes a wireless communication device (WCD) 510 (although the AP 502 itself may also be generally referred to as a wireless communication device as used herein). For example, the wireless communication device 510 may be an exemplary implementation of the wireless communication device 400 described with reference to FIG. 4. The AP 502 also includes multiple antennas 520 coupled to the wireless communication device 510 for transmitting and receiving 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 that enables the AP 502 to communicate with a core network or a backhaul network to provide access to external networks, 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). Some of the above-mentioned components may communicate directly or indirectly with some of the other components via at least one bus. The AP 502 further includes a housing that contains the wireless communication device 510, the application processor 530, the memory 540, and at least a portion of the antenna 520 and the external network interface 550.

[0048] FIG. 5B illustrates a block diagram of an exemplary STA 504. For example, the STA 504 may be an exemplary implementation of the STA 104 described with reference to FIG. 1. The STA 504 includes a wireless communication device 515 (although the STA 504 itself may also be generally referred to as a wireless communication device as used herein). For example, the wireless communication device 515 may be an exemplary implementation of the wireless communication device 400 described with reference to FIG. 4. The STA 504 also includes one or more antennas 525 coupled with the wireless communication device 515 for transmitting and receiving wireless communications. The STA 504 additionally includes an application processor 535 coupled with the wireless communication device 515 and a memory 545 coupled with the application processor 535. In some implementations, the STA 504 further includes a user interface (UI) 555 (such as a touch screen or keypad) and a display 565, which may 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, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. Some of the above-mentioned components may communicate directly or indirectly with other components via at least one bus. The STA 504 further includes a housing that contains the wireless communication device 515, the application processor 535, the memory 545, and at least a portion of the antenna 525, the UI 555, and the display 565.

[0049] The term "distributed transmission" as used herein refers to the transmission of a PPDU on non-contiguous tones (or subcarriers) of a wireless channel (e.g., according to a "distributed tone plan"). Such non-contiguous tones represent dRUs. In contrast, rRUs are any set of contiguous tones defined by existing versions of the IEEE 802.11 standard (also referred to as "non-distributed tone plan"). Distributed transmission provides greater flexibility in medium utilization for PSD-limited wireless channels. As explained above, the LPI power class limits the transmit power of APs and STAs to 5 dBm / MHz and -1 dBm / MHz, respectively, in the 6 GHz band. By allowing a wireless communication device to distribute the tones allocated for the transmission of a PPDU across non-contiguous subcarrier indexes of a wireless channel, distributed transmission may increase the overall transmit power of the PPDU without exceeding the PSD limit of the wireless channel. For example, a distributed tone plan may reduce the total number of tones modulated by a device on any 1 MHz subchannel of a wireless channel. As a result, a wireless communication device may increase its per-tone transmit power without exceeding the PSD limit.

[0050] Various aspects relate generally to distributed transmissions, and more particularly, to STF design and signaling to support distributed transmissions. In some aspects, a transmitting device may transmit data on a dRU and may transmit an STF sequence over the spreading bandwidth of the dRU according to an existing STF tone plan. Thus, in a TB PPDU, STAs assigned a dRU within the same spreading bandwidth may transmit the same STF sequence on the same set of tones. In some implementations, each STA that is assigned a dRU for transmission in a TB PPDU may map its STF sequence to one or more spatial streams and may apply one or more global CSDs to the STF sequences mapped to the one or more spatial streams, respectively. As used herein, the term "global CSD" refers to a CSD assignment that takes into account the location of each STA associated with the PPDU. For example, different global CSDs may be assigned to different STAs such that each STA transmits its STF sequence with a different amount of delay. In some implementations, each STA may randomly generate its global CSD value. In some other implementations, each STA may select its global CSD value from the CSD table based on information assigned to the STA (such as an AID value or RU index, RU allocation index, or starting tone offset associated with the dRU). Still further, in some implementations, each STA may receive an indication of its global CSD index or value in a trigger frame requesting a TB PPDU. In some aspects, the trigger frame may carry distributed transmission information indicating which STAs have been allocated dRUs for transmission in the TB PPDU, and may carry dRU distributed bandwidth information indicating the spreading bandwidth associated with the dRU.

[0051] Particular implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages: As described above, transmitting the data portion of the PPDU on discontinuous tones of a wireless channel allows a transmitting device to increase the overall transmit power of the data without exceeding the PSD limit of the wireless channel. Transmitting the STF of the PPDU over the spreading bandwidth of the dRU allows a receiving device to more accurately estimate the power of the received signal associated with the data portion. By reusing the existing STF tone plan, aspects of the present disclosure may support AGC for distributed transmissions with minor modifications to the IEEE 802.11 standard. However, aspects of the present disclosure recognize that unintended beamforming may result from multiple STAs simultaneously transmitting the same STF sequence on the same set of tones (such as in a TB PPDU). For example, such superimposed STF transmissions may constructively or destructively interfere at a receiving device, causing the receiving device to obtain inaccurate power measurements for the received signal. By applying a global CSD to the STF sequences transmitted by each STA on each spatial stream, aspects of the present disclosure may separate STF transmissions from multiple STAs in the time domain. More specifically, the global CSD may stagger the phase of STF transmissions across different STAs and different spatial streams, thereby preventing or reducing unintended beamforming at a receiving device.

[0052] FIG. 6 illustrates a frequency diagram 600 showing an example distributed tone mapping according to some implementations. More specifically, FIG. 6 illustrates an example mapping of a payload 601 of a PPDU 602 to a set of tones or subcarriers for transmission over a wireless channel. In some implementations, the payload 601 may be modulated on a logical RU 604 associated with a non-distributed tone plan (such as a legacy tone plan or a non-legacy tone plan) and further mapped to a dRU 606 according to the distributed tone plan. The logical RU 604 represents the number of tones or subcarriers that are allocated for transmission of the PPDU 602. In contrast, the dRU 606 represents the physical resource (identified by a subcarrier index) that is modulated to transmit the PPDU 602. As used herein, the term "distributed RU" or dRU refers to any logical RU distributed across a set of non-contiguous subcarrier indexes, and the term "distributed tone plan" refers to a set of non-contiguous subcarrier indexes associated with a dRU.

[0053] Existing versions of the IEEE 802.11 standard define a number of RUs and multiple RUs (MRUs) of various sizes that map to consecutive tones or subcarriers across a frequency bandwidth (or wireless channel). For example, a 242-tone RU maps to 242 consecutive subcarrier indices across a 20 MHz bandwidth. Similarly, a 484+242-tone MRU maps to 484 consecutive subcarrier indices across a 40 MHz bandwidth and 242 consecutive subcarrier indices across a 20 MHz bandwidth. As used herein, the term "regular RU" or rRU refers to any RU or MRU configuration supported by existing versions of the IEEE 802.11 standard (up to and including the IEEE 802.11be amendment of the IEEE 802.11 standard), and the term "non-distributed tone plan" refers to any tone plan defined by existing versions of the IEEE 802.11 standard. Additionally, the term "legacy" may be used herein to refer to PPDU formats and communication protocols that comply with the IEEE 802.11ax amendment or earlier versions of the IEEE 802.11 standard. For example, a "legacy tone plan" may be any non-distributed tone plan supported by the IEEE 802.11ax amendment. In contrast, the term "non-legacy" as used herein is used herein to refer to PPDU formats and communication protocols that comply with the IEEE 802.11be amendment and future generations of the IEEE 802.11 standard. For example, a "non-legacy tone plan" may be any non-distributed tone plan supported by the IEEE 802.11be amendment.

[0054] In some implementations, the logical RU 604 may represent an rRU defined by an existing version of the IEEE 802.11 standard. In other words, the logical RU 604 maps directly to each rRU according to a non-distributed tone plan. In the example of FIG. 6, the logical RU 604 includes 26 tones. Thus, according to a non-distributed tone plan, the logical RU 604 will map directly to 26 contiguous or consecutive subcarrier indexes across a 2 MHz subchannel. However, when mapped to an rRU, the transmit power of the logical RU 604 may be severely limited based on the PSD of the wireless channel. For example, the LPI power class limits the transmit power of the AP and STA to 5 dBm / MHz and −1 dBm / MHz, respectively, in the 6 GHz band. Thus, the transmit power per tone of the logical RU 604 is limited by the number of tones mapped to each 1 MHz subchannel of the wireless channel. Thus, each 1 MHz subchannel of a PSD-limited channel may be referred to herein as a “PSD-limited subchannel.”

[0055] Aspects of the present disclosure recognize that distributing the tones over a wider bandwidth may increase the transmit power per tone of the logical RU 604. Increasing the transmit power per tone may also increase the overall transmit power of the logical RU 604. Thus, in some implementations, the logical RU 604 may be mapped to a set of non-contiguous subcarrier indices across a wider bandwidth channel (referred to herein as a "spread bandwidth" or "distributed bandwidth"). For example, with reference to FIG. 6, the logical RU 604 is mapped to the dRU 606 according to a distributed tone plan. More specifically, the logical RU 604 is mapped to 26 non-contiguous subcarrier indices spread across a 40 MHz wireless channel (where the spread bandwidth is equal to 40 MHz). Compared to the tone mapping described above with respect to the non-distributed tone plan, the distributed tone mapping shown in FIG. 6 effectively reduces the number of tones (of the logical RU 604) for each 1 MHz subchannel. For example, each of the 26 tones may be mapped to a different 1 MHz subchannel of the 40 MHz channel. As a result, each AP or STA that implements the distributed tone mapping of FIG. 6 can maximize its per-tone transmit power (and thereby maximize the overall transmit power of the logical RU 604).

[0056] In some implementations, the transmitting device (such as a STA or AP) may include a distributed tone mapper that maps the logical RU 604 to the dRU 606 in the frequency domain (as described with reference to FIG. 6). The dRU 606 is then converted (such as by an inverse fast Fourier transform (IFFT)) to a time domain signal for transmission over a wireless channel. The receiving device (such as an AP or STA) receives the time domain signal over the wireless channel and converts (such as by a fast Fourier transform (FFT)) the time domain signal back to the dRU 606. In some implementations, the receiving device may include a distributed tone demapper that demaps the dRU 606 to the logical RU 604. In other words, the distributed tone demapper reverses the mapping performed by the distributed tone mapper in the transmitting device. The receiving device may then recover the information carried (or modulated) on the logical RU 604 as a result of the demapping.

[0057] In the example of Figure 6, the logical RUs 604 are uniformly distributed across the 40 MHz wireless channel. However, in an actual implementation, the logical RUs 604 may be mapped to any suitable pattern of non-contiguous subcarrier indexes. For example, in some aspects, the distance between any pair of modulated tones may be different (smaller or larger) than that shown in Figure 6. Still further, in some aspects, multiple logical RUs may be mapped to interleaved subcarrier indexes of a shared wireless channel.

[0058] 7 shows a frequency diagram illustrating an example mapping of logical RUs 702 and 704 to dRUs 706 and 708, according to some implementations. In some implementations, each of the logical RUs 702 and 704 may carry user data for a respective AP or STA (not shown for simplicity).

[0059] In the example of FIG. 7, each of the logical RUs 702 and 704 includes 26 tones, with a spreading bandwidth equal to 40 MHz. In some implementations, the logical RUs 702 and 704 are mapped to the dRUs 706 and 708, respectively, according to a distributed tone plan. More specifically, the 26 tones associated with each of the logical RUs 702 and 704 are mapped to a respective set of 26 non-contiguous subcarrier indexes spread across a 40 MHz wireless channel. In some implementations, the distributed tone plan maps the 26 tones of the first logical RU 702 to every 18 subcarrier indexes starting with subcarrier index 1, and maps the 26 tones of the second logical RU 704 to every 18 subcarrier indexes starting with subcarrier index 10. As a result, the first dRU 706 contains every 18th tone modulated on subcarrier indexes 1 to 451, and the second dRU 708 contains every 18th tone modulated on subcarrier indexes 10 to 460.

[0060] As shown in Figure 7, the first tone (tone_idx=1) of logical RU 702 is mapped to subcarrier index 1, the second tone (tone_idx=2) of logical RU 702 is mapped to subcarrier index 19, and the mapping pattern continues until the 26th tone (tone_idx=26) of logical RU 702 is mapped to subcarrier index 451. Similarly, the first tone (tone_idx=1) of logical RU 704 is mapped to subcarrier index 10, the second tone (tone_idx=2) of logical RU 704 is mapped to subcarrier index 28, and the mapping pattern continues until the 26th tone (tone_idx=26) of logical RU 704 is mapped to subcarrier index 460. Thus, as shown in Figure 7, the distributed tone plan interleaves logical RUs 702 and 704 offset by 9 subcarrier indexes across the dRU spreading bandwidth. Aspects of the present disclosure recognize that by interleaving dRUs 706 and 708, the transmit power per tone of each dRU can be significantly increased without sacrificing spectral efficiency.

[0061] Aspects of the present disclosure recognize that new packet designs are required to support distributed transmission. For example, existing versions of the IEEE 802.11 standard define a PPDU format that includes a PHY preamble followed by a payload. As described with reference to FIG. 6 and FIG. 7, the payload may be transmitted on a dRU to achieve increased transmit power. The PHY preamble includes one or more STFs that may be used for AGC or DC estimation at the receiving device. For example, a transmitting device may transmit a known pattern of symbols within the STF to a receiving device. The receiving device may use its knowledge of the symbol pattern and its periodicity within the received STF (also referred to as an "STF sequence") to estimate the power of the received signal and perform DC estimation. Furthermore, the receiving device may dynamically adjust its amplifier gain based on the estimated power of the STF to correct the DC of the received signal to ensure more accurate reception of the data portion of the PPDU. Existing versions of the IEEE 802.11 standard define various STF sequences and tone plans (also referred to as "existing STF tone plans") associated with various PPDU formats and bandwidths. According to existing versions of the IEEE 802.11 standard, rRUs transmit over their respective bandwidths (or sub-bands) exclusively allocated for them, and the STF associated with each rRU is transmitted over an STF tone within that rRU. However, as shown in FIG. 7, multiple dRUs may transmit over interleaved tones of a shared bandwidth. Because the STF is used to estimate the signal power of the modulated tones, changing the tone plan used for PPDU transmission (such as from a non-distributed tone plan to a distributed tone plan) may require new dRU-related signaling and STF design.

[0062] 8 illustrates an example PPDU 800 that may be used for communication between an AP and one or more STAs, according to some implementations. In some implementations, the PPDU 800 may be an example of the PPDU 602 of FIG. 6. The PPDU 800 includes a PHY preamble that includes a first portion 802 and a second portion 804. The PPDU 800 may further include a PHY payload 806 after the preamble, e.g., in the form of a PSDU carrying a DATA field 826. In some implementations, the PPDU 800 may be formatted as a non-legacy or Extremely High Throughput (EHT) PPDU.

[0063] The first portion 802 of the PHY preamble includes an L-STF 808, an L-LTF 810, an L-SIG 812, a repeated legacy signal field (RL-SIG) 814, and a universal signal field (U-SIG) 816. In some implementations, the first portion 804 of the PHY preamble may further include a non-legacy signal field (EHT-SIG) 818. With reference to the IEEE 802.11be amendment of the IEEE 802.11 standard, the first portion 802 may be referred to as the “pre-EHT modulated portion” of the PPDU 800. The second portion 804 of the PHY preamble includes a non-legacy short training field (EHT-STF) 822 and several non-legacy long training fields (EHT-LTF) 824. With reference to the IEEE 802.11be amendment of the IEEE 802.11 standard, the second portion 804, together with the PHY payload 806, may be referred to as the “EHT modulated portion” of the PPDU 800.

[0064] For example, referring to FIG. 6, PHY payload 806 may be an example of payload 601. PHY payload 806 may be modulated on logical RUs that are further mapped to dRUs, for example, to achieve a gain in transmit power. As described with reference to FIG. 6 and FIG. 7, the tones of the dRUs are distributed across non-contiguous subcarrier indexes associated with a wireless channel. The bandwidth of the wireless channel is called the spreading bandwidth (BW) or "distribution bandwidth." To achieve non-contiguous tone distribution, the bandwidth of the logical RUs on which PHY payload 806 is modulated must be smaller than the spreading bandwidth. For example, as shown in FIG. 6, payload 601 is modulated on a 26-tone logical RU 604 having a bandwidth of about 2 MHz, and the tones of logical RU 604 are further distributed across 26 non-contiguous subcarrier indexes associated with a 40 MHz spreading bandwidth.

[0065] The EHT-STF 822 carries a sequence of values ​​(or STF sequence) used for AGC at the receiving device. More specifically, the receiving device measures the power of the received STF signal and adjusts the gain of its amplifier to more accurately receive the PHY payload 806 based on the measured power of the EHT-STF 822. Thus, in some aspects, the EHT-STF 822 may also be transmitted across the spread bandwidth of the dRU. Existing versions of the IEEE 802.11 standard define an STF tone plan that maps values ​​of the STF sequence to respective tones associated with a wireless channel. For example, an existing STF tone plan associated with a TB PPDU modulates every eight tones in the wireless channel with a respective STF value. In some implementations, the EHT-STF 822 may be mapped to a sequence of tones across the spread bandwidth according to an existing STF tone plan. In other words, the distributed transmission may reuse an existing EHT-STF sequence that is mapped to respective tones in the spread bandwidth according to an existing STF tone plan.

[0066] FIG. 9 illustrates a frequency diagram 900 illustrating an example STF sequence 902 that can be used for AGC in distributed transmission. In some implementations, the STF sequence 902 can be an example of the EHT-STF 822 of FIG. 8. In the example of FIG. 9, the STF sequence 902 is mapped to a 40 MHz spreading bandwidth according to an existing STF tone plan defined for a TB PPDU. In some implementations, the STF sequence 902 can be an existing STF sequence defined for a 484-tone rRU. As shown in FIG. 9, values ​​of the STF sequence 902 are mapped to every 8 subcarrier indexes in the range of subcarrier indexes from −248 to 248 (centered around DC) across the 40 MHz spreading bandwidth. As shown in FIG. 9, a first value of STF sequence 902 is modulated onto subcarrier index −248, a second value of STF sequence 902 is modulated onto subcarrier index −240, a third value of STF sequence 902 is modulated onto subcarrier index −232, and the mapping is repeated until the last value of STF sequence 902 is mapped to subcarrier index 248.

[0067] Aspects of the present disclosure recognize that by defining each STF sequence and tone mapping scheme for a given spreading bandwidth, the same STF sequence may be transmitted (on the same set of tones) by multiple STAs assigned to different dRUs that are allocated for transmission within the same spreading bandwidth. For example, referring to FIG. 7, an STF sequence 902 may be transmitted by a first STA assigned to dRU 706 and a second STA assigned to dRU 708. In some aspects, the first and second STAs may simultaneously transmit the STF sequence 902 to a receiving device (such as in a TB PPDU), which may result in unintended beamforming at the receiving device. For example, the receiving device may receive multiple copies of the STF sequence 902 superimposed on each other. However, the random phase from the transmitters of the first and second STAs may cause the received signals to constructively or destructively interfere with each other, which is most noticeable when they have the same channel response (such as additive white gaussian noise (AWGN)). As a result, the measured power associated with the STF may be significantly higher or lower than the actual power associated with either the dRU 706 or 708.

[0068] 10 illustrates an example frame structure for a TB PPDU 1000 according to some implementations. The TB PPDU 1000 includes a pre-EHT modulated portion 1002 followed by an EHT modulated portion 1004. The pre-EHT modulated portion 1002 includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, and a U-SIG. The EHT modulated portion 1004 includes an EHT-STF, an EHT-LTF, and a data portion. In some implementations, the TB PPDU 1000 may be an example of the PPDU 800 of FIG. 8 (excluding the EHT-SIG 818).

[0069] In the example of Figure 10, the TB PPDU 1000 may be transmitted over a 40 MHz bandwidth. To ensure proper packet detection and backward compatibility with wireless communication devices that comply with existing versions of the IEEE 802.11 standard, the pre-EHT modulated portion 1002 of the TB PPDU 1000 may be replicated on each 20 MHz sub-band of the 40 MHz bandwidth. For example, information carried in the L-STF, L-LTF, L-SIG, RL-SIG, and U-SIG may be transmitted on the first 20 MHz, and the same information may be replicated on the second 20 MHz sub-band.

[0070] In contrast, the EHT modulation portion 1004 may be configured for transmission over a 40 MHz bandwidth as a whole. For example, a first data portion of the TB PPDU 1000 may be assigned to a first dRU 1002 mapped to a 40 MHz bandwidth, and a second data portion of the TB PPDU 1000 may be assigned to a second dRU 1004 mapped to a 40 MHz bandwidth. In some implementations, the dRUs 1002 and 1004 may be examples of the dRUs 702 and 704, respectively, of FIG. 7. Thus, the dRUs 1002 and 1004 may be transmitted on interleaved tones within the same 40 MHz spreading bandwidth.

[0071] In some implementations, the first dRU 1002 may be assigned to a first STA (STA1), and the second dRU 1004 may be assigned to a second STA (STA2). In other words, STA1 may transmit its data on the dRU 1002 in the first data portion of the TB PPDU 1000, and STA2 may transmit its data on the dRU 1004 in the second data portion of the TB PPDU 1000. The EHT-LTF carries a sequence of values ​​(also referred to as an "LTF sequence") used for channel estimation at the receiving device. Thus, the EHT-LTF may be transmitted on the same tones as the data portion of the TB PPDU 1000. For example, STA1 may transmit an LTF sequence on the dRU 1002 in the EHT-LTF of the TB PPDU 1000, and STA2 may transmit an LTF sequence on the dRU 1004 in the EHT-LTF of the TB PPDU. In some aspects, the EHT-STF may carry an existing STF sequence associated with a 40 MHz bandwidth (as shown in FIG. 9). Thus, STA1 and STA2 may transmit the same STF sequence on the same set of tones within the EHT-STF of the TB PPDU 1000.

[0072] In some aspects, STA1 and STA2 may each transmit a respective portion of the TB PPDU 1000 over one or more spatial streams. For example, STA1 may transmit its portion of the TB PPDU 1000 (including the EHT-STF and the EHT modulated portion 1004 mapped to the dRU 1002) over a certain number (m) of spatial streams. In some implementations, STA1 may apply m CSDs to the portions of the TB PPDU 1000 mapped to the m spatial streams, respectively, to avoid unintended beamforming across the m spatial streams at the receiving device. Similarly, STA2 may transmit its portion of the TB PPDU 1000 (including the EHT-STF and the EHT modulated portion 1004 mapped to the dRU 1004) over a certain number (n) of spatial streams. In some implementations, STA2 may apply n CSDs respectively to portions of the TB PPDU 1000 mapped to the n spatial streams to avoid unintentional beamforming across the n spatial streams at the receiving device.

[0073] Aspects of the present disclosure recognize that because dRUs 1002 and 1004 are separated in frequency, local CSD may be sufficient to overcome unintended beamforming in the EHT-LTF and data portions of the TB PPDU 1000. In other words, STA1 may apply its m CSDs "locally" or without considering the n CSDs applied by STA2. Unintended beamforming in the EHT-LTF and data portions of the TB PPDU 1000 may be avoided even if the m CSDs applied to the EHT-LTF and data portions mapped to the m spatial streams are equal to the n CSDs (or a subset or superset thereof) applied to the EHT-LTF and data portions mapped to the n spatial streams.

[0074] However, because STA1 and STA2 transmit the EHT-STF of the TB PPDU 1000 on the same set of tones, unintended beamforming across the m+n spatial streams may still occur if STA1 and STA2 apply only local CSD to their respective spatial streams. For example, if the m CSDs applied to the EHT-STF mapped to the m spatial streams are equal to the n CSDs (or a subset or superset thereof) applied to the EHT-STF mapped to the n spatial streams, unintended beamforming may still occur in the EHT-STF of the TB PPDU 1000 as a result of cross-correlation between the m spatial streams transmitted by STA1 and the n spatial streams transmitted by STA2.

[0075] In some aspects, each STA assigned a dRU for transmission in the TB PPDU may apply one or more global CSDs to the EHT-STFs of the TB PPDU mapped to one or more spatial streams, respectively. As described above, the global CSD takes into account the location of each STA associated with the TB PPDU. For example, the global CSD value assigned to each STA associated with the TB PPDU may be different from the global CSD value assigned to any other STA associated with the TB PPDU. For example, with reference to FIG. 10, STA1 may apply m global CSD values ​​to the EHT-STFs mapped to m spatial streams, respectively, and STA2 may apply n global CSD values ​​to the EHT-STFs mapped to n spatial streams, respectively, resulting in different CSDs being applied to the EHT-STFs mapped to each of the m+n spatial streams. Thus, the global CSD effectively separates EHT-STF transmissions from multiple STAs in the time domain, thereby avoiding unintended beamforming at the receiving device.

[0076] In some implementations, a global CSD may be applied to the entire EHT modulated portion 1004 of the TB PPDU 1000. In such implementations, the transmitting device may apply the same phase slope (or the same CSD value) to the EHT-STF, EHT-LTF, and data portions of the TB PPDU 1000, which may simplify the transmitter implementation of the TB PPDU 1000. In some implementations, applying a global CSD to the EHT-LTF may help reduce the receiver-side peak-to-average power ratio (PAPR) or resolve unintended beamforming issues associated with transmitting the EHT-LTF. However, aspects of the present disclosure also recognize that existing versions of the IEEE 802.11 standard only support the use of local CSD in transmitting and receiving EHT-LTF and data in a TB PPDU with UL OFDMA. Thus, applying a global CSD to the entire EHT modulated portion 1004 may require modifications to the transmitter and receiver implementation of the TB PPDU 1000.

[0077] In some other implementations, the global CSD may be applied only to the EHT-STF of the TB PPDU 1000. In such implementations, the transmitting device may apply a different phase gradient (or a different CSD value) to the EHT-STF than the EHT-LTF and data portions of the TB PPDU 1000, which may add more complexity to the transmitter implementation of the TB PPDU 1000. However, the local CSD may be applied to the EHT-LTF and data portions of the TB PPDU 1000 in compliance with existing versions of the IEEE 802.11 standard. Aspects of the present disclosure further recognize that the processing of the EHT-STF at the receiving device is not dependent on (or affected by) the value of the CSD. Thus, applying the global CSD exclusively to the EHT-STF may reduce or minimize changes required to the transmitter and receiver implementations of the TB PPDU 1000.

[0078] 11 illustrates a block diagram of an example transmit (TX) processing chain 1100 of a wireless communication device according to some implementations. More specifically, the TX processing chain 1100 may be configured to transmit an STF sequence 1102 representing an EHT-STF of a PPDU (such as the EHT-STF 822 of FIG. 8 or the EHT-STF of FIG. 10). In some other implementations, the wireless communication device may be an AP, such as any of the APs 102 or 502 of FIG. 1 and FIG. 5A, respectively. In some other implementations, the wireless communication device may be a STA, such as any of the STAs 104 or 504 of FIG. 1 and FIG. 5B, respectively.

[0079] The TX processing chain 1100 includes an STF sequence selector 1110, a CSD phase rotator 1130, a spatial stream (SS) mapper 1140, and a number (N) of inverse fast Fourier transforms (IFFTs) 1150(1)-1150(n). The STF sequence selector 1110 selects an STF sequence 1102 to be transmitted in the PPDU. In some aspects, the STF sequence selector 1110 may select the STF sequence 1102 based on a spreading bandwidth 1101 associated with a dRU allocated for transmission in the PPDU by the wireless communication device. In some implementations, the STF sequence selector 1110 may select an STF sequence 1102 that maps to the spreading bandwidth 1101 according to an existing version of the IEEE 802.11 standard (as described with reference to FIG. 8 and FIG. 9). The selected STF sequence 1102 is copied onto a number (n) of data streams.

[0080] The phase rotator 1130 is configured to apply the n CSDs to the n data streams of the STF sequence 1102, respectively, to generate a phase-rotated STF sequence 1104. For example, the CSD may add a phase rotation or delay to one or more of the n data streams to prevent unintended beamforming at a receiving device. As described with reference to FIGS. 8-10, multiple STAs may transmit the same STF sequence simultaneously on the same set of tones when assigned respective dRUs within the same spreading bandwidth. In some aspects, the phase rotator 1130 may assign a respective global CSD value to each of the n CSDs to prevent unintended beamforming across multiple STAs. For example, the phase rotator 1130 may determine or select the n global CSD values ​​depending on the allocation of dRUs for transmission in the TB PPDU.

[0081] The SS mapper 1120 maps the phase-rotated n-stream STF sequence 1104 onto the N TX chain signals SS to generate spatially mapped STF sequences 1106. 1 ~SS N For example, the SS mapper 1120 may apply a spatial mapping matrix (such as a Q matrix) to the modulation values ​​associated with the STF sequence 1104. As a result of the spatial mapping, each of the data streams is projected onto a respective transmitter chain (as a spatially mapped STF sequence 1106). The IFFTs 1150(1) through 1150(N) map the N TX chain signals SS 1 ~SS N Each of the IFFTs 1150 converts the above STF sequence 1106 from the frequency domain to the time domain. For example, each IFFT 1150 may generate a respective series of time-varying samples representing the modulation values ​​mapped to each spatial stream. The time-varying samples represent a time-domain STF signal 1108 that may be transmitted via a wireless channel via n transmitter chains (not shown for simplicity).

[0082] Aspects of the present disclosure recognize that the effectiveness of the phase rotator 1130 in separating the STF signal 1108 from any STF signals simultaneously transmitted by other wireless communication devices depends on the uniqueness of the global CSD value. Ideally, the global CSD value applied by the phase rotator 1130 should be different from the global CSD value applied by any other wireless communication devices associated with the same TB PPDU. Thus, in some implementations, the phase rotator 1130 may derive the global CSD value based on global CSD derivation information 1103 that is specific to the wireless communication device. In some aspects, the global CSD derivation information 1103 may include information assigned to the wireless communication device. Exemplary suitable information may include an association identifier (AID) value, an RU index or RU allocation index associated with its assigned dRU, or a starting tone offset associated with its assigned dRU, among other examples.

[0083] In some implementations, the phase rotator 1130 may randomly generate the n global CSD values, for example, using a random number generator or in response to information assigned to the wireless communication device. For example, the global CSD values ​​may be generated as a function of the AID value, a maximum (M) global CSD value (e.g., 800 ns), a granularity (Δ) of the global CSD value (e.g., 25 ns), and a desired distance or spacing (D) between the AID values ​​according to Equation 1.

[0084]

number

[0085]

number

[0086] In some other implementations, a number (N) of global CSD values ​​may be defined for all dRU transmissions in general. In such implementations, each wireless communication device supporting distributed transmission has knowledge of the same N global CSD values. For example, each of the N global CSD values ​​may be stored as a respective entry in the CSD table 1132. In some implementations, N may be equal to 8. An example CSD table with 8 entries (N=8) is shown below, where the value of each entry indicates a respective delay amount (in ns): [0 -400 -200 -600 -350 -650 -100 -750]

[0087] In some other implementations, N may be equal to 16. Aspects of the present disclosure recognize that increasing the number of distinct global CSD values ​​(larger values ​​of N) reduces the likelihood of collisions. However, a larger CSD table may also require modifications to the IEEE 802.11 standard and transmitter implementation. An example CSD table with 16 entries (N=16) is shown below, with the value of each entry indicating a respective amount of delay (in ns): [0 -400 -200 -600 -350 -650 -100 -750 -250 -550 -300 -450 -50 -700 -150 -500] Another exemplary CSD table is shown below with 16 entries (N=16), where the values ​​in the last 8 entries are rotated versions of the first 8 entries. [0 -400 -200 -600 -350 -650 -100 -750(0+Δ)(-400+Δ)(-200+Δ)(-600+Δ)(-350+Δ)](-650+Δ)(-100+Δ)(-750++Δ)] In the above CSD table, Δ represents a phase offset (such as 50 ns) that may be applied to each of the first eight entries of the CSD table to generate the last eight entries of the CSD table.

[0088] In some implementations, the phase rotator 1130 may algorithmically determine a starting index associated with the CSD table 1132 based on information assigned to the wireless communication device (STA_assignment_info). For example, the starting index may be calculated as a function of STA_assignment_info and N according to Equation 2. start index=mod(STA_assignment_info,N)+1 (2) Based on Equation 2, the starting index will have a value between 0 and N-1 that points to one of the N entries of the CSD table 1132. Thus, the phase rotator 1130 may use the starting index to determine an initial global CSD value for the wireless communication device. In some implementations, the phase rotator 1130 may determine the remaining n-1 global CSD values ​​by incrementing the starting index (e.g., by a factor of n-1) and retrieving the corresponding entries from the CSD table 1132.

[0089] In some implementations, the STA_assignment_info may be an AID value assigned to the wireless communication device. For example, each STA associated with a BSS is assigned an AID value that identifies the STA within the BSS. The AID value is known to the wireless communication device upon association with the BSS and may be used to identify user-specific information carried in the trigger frame (e.g., in the user information field). In some other implementations, the STA_assignment_info may be an RU assignment index or RU index associated with a dRU assigned to the wireless communication device. For example, the trigger frame may allocate a dRU to a STA based on an RU assignment index that conforms to an existing RU allocation table. The RU assignment index or RU index may indicate the size and relative position of a dRU (such as a first 26-tone dRU in a 40 MHz bandwidth, a second 26-tone dRU in a 40 MHz bandwidth, a first 52-tone dRU in an 80 MHz bandwidth, or a second 52-tone dRU in an 80 MHz bandwidth, among other examples) within a given bandwidth.

[0090] Still further, in some implementations, the STA_assignment_info may be a starting tone offset associated with a DRU assigned to the wireless communication device. For example, dRUs mapped to the same spreading bandwidth are offset from each other by a number of subcarrier indexes depending on the size of each dRU and its RU index. The distance between the first tone of a dRU of a given size and the first tone of the first dRU of that size is referred to herein as the "starting tone offset." For example, referring to FIG. 7, dRU 706 has a starting tone offset equal to 0 because it is the first 26-tone dRU mapped to a 40 MHz spreading bandwidth. In contrast, dRU 708 has a starting tone offset equal to 9 because it is the second 26-tone dRU mapped to a 40 MHz spreading bandwidth and the first tone of dRU 708 (mapped to subcarrier index 10) is offset by 9 subcarrier indexes from the first tone of dRU 706 (mapped to subcarrier index 1).

[0091] Aspects of the present disclosure recognize that collisions cannot be completely avoided when each STA derives its own global CSD value (randomly or algorithmically). For example, some BSSs may randomly assign the same AID value to multiple STAs. Thus, when STA_assignment_info is the AID value of a wireless communication device, Equations 1 and 2 may generate the same CSD value for STAs assigned the same AID value. Furthermore, when STA_assignment_info is an RU assignment index, Equation 2 may generate the same CSD value for multiple RU assignment indexes (because the RU allocation table is fixed). For example, modulo arithmetic generates the same CSD value of 1 for RU assignment indexes 0 and 8 (N=8). A similar problem may occur when STA_assignment_info is a starting tone offset. For example, the first 26-tone dRU in a 20 MHz spreading bandwidth has a starting tone offset equal to 0, and the fifth 26-tone dRU in a 20 MHz bandwidth has a starting tone offset equal to 8. Therefore, when the STA_assignment_info is the starting tone offset, Equation 2 may produce the same CSD value for multiple dRU assignments.

[0092] Aspects of the present disclosure further recognize that dRU configurations follow a hierarchical structure. In other words, a larger dRU is constructed from multiple smaller dRUs. Table 1 shows example hierarchical dRU structures for a 26-tone dRU (dRU26), a 52-tone dRU (dRU52), and a 106-tone dRU (dRU106) associated with a 20 MHz bandwidth.

[0093] [Table 1]

[0094] This hierarchical structure can prevent overlapping dRUs from being allocated for transmission in the same frequency bandwidth or subband. Thus, in some aspects, a new global CSD starting index table can be designed based on the hierarchical dRU structure to further reduce the probability of CSD collision. Table 2 shows an example global CSD starting index table associated with a 20 MHz bandwidth, where each entry in Table 2 maps to a respective dRU index (or dRU allocation index) in Table 1.

[0095] [Table 2]

[0096] In some implementations, the value of the global CSD start index table may be used instead of Equation 2 to determine the global CSD value for each STA. For example, in a 20 MHz spreading bandwidth, dRU26 1 A STA that is assigned a starting tone index (RU allocation index=0 and starting tone offset=0) will determine that its starting index is equal to 1 according to Table 2.

[0097] In some aspects, the receiving device (or the device requesting the TB PPDU) may assign a global CSD value to each STA associated with the TB PPDU. For example, the receiving device may provide an indication of the global CSD value assigned to each STA in a trigger frame requesting the TB PPDU. In some implementations, the trigger frame may carry CSD information indicating a respective starting index assigned to each of the STAs associated with the TB PPDU. In such implementations, the phase rotator 1130 may receive the starting index as the global CSD derivation information 1103 and retrieve the appropriate CSD value indicated by the starting index from the CSD table 1132. In some implementations, the trigger frame may carry distributed transmission information indicating whether the RU allocation index allocated to each STA represents an rRU or a dRU, and may carry dRU distributed bandwidth information indicating the spreading bandwidth associated with each dRU.

[0098] 12 illustrates an example trigger frame 1200 that may be used for communication between an AP and one or more STAs, according to some implementations. The trigger frame 1200 may be used to request a TB PPDU (such as the TB PPDU 1000 of FIG. 10) from one or more STAs. For example, referring to FIG. 1, the AP 102 may transmit the trigger frame 1200 to request a TB PPDU from one or more of the STAs 104. The trigger frame 1200 may allocate resources (such as one or more rRUs or dRUs) for transmission in the TB PPDU.

[0099] The trigger frame 1200 includes a MAC header 1210, a common information field 1220, a user information list 1230, zero or more padding bits 1240, and an FCS 1250. The MAC header 1210 includes a frame control field, a duration field, a receiver address (RA) field, and a transmitter address (TA) field. The common information field 1220 and the user information list 1230 carry configuration information that may be used by a receiving device to configure a TB PPDU to be transmitted in response to receiving the trigger frame 1200. In some aspects, the user information list 1230 may include one or more user information fields 1232, each carrying per-user information for a respective user. In contrast, the common information field 1220 may carry information that is common to all recipients of the trigger frame 1200 (e.g., any users identified in the user information list 1230).

[0100] In some implementations, each user information field 1232 may carry RU allocation information 1233, distributed transmission information 1234, dRU distributed bandwidth information 1235, and dRU CSD start index 1236. The RU allocation information 1233 indicates a logical RU (or MRU) that is allocated to the user associated with the user information field 1232, and the distributed transmission information 1234 indicates whether the logical RU is mapped to an rRU or a dRU. If the distributed transmission information 1234 indicates that the logical RU is a dRU, then the dRU distributed bandwidth information 1235 may indicate a spreading bandwidth associated with the dRU, and the dRU CSD start index 1236 may point to a respective entry of a global CSD table that stores a number (N) of global CSD values.

[0101] In some implementations, the global CSD table (such as the CSD table 1132 in FIG. 11) may store eight global CSD values ​​(N=8). In such implementations, the dRU CSD start index 1236 may be a three-bit value that points to a separate entry in the global CSD table. In some other implementations, the global CSD table may store sixteen global CSD values ​​(N=16). In such implementations, the dRU CSD start index 1236 may be a three-bit value that points to a respective entry in the top half of the global CSD table or a respective entry in the bottom half of the global CSD table. In some implementations, the user information field 1232 may further carry disambiguation information (such as an additional bit) that signals whether the dRU CSD start index 1236 points to an entry in the top half of the global CSD table or to an entry in the bottom half of the global CSD table.

[0102] In some other implementations, the disambiguation information may be signaled implicitly. For example, a STA associated with the user information field 1232 may derive the disambiguation information based on other information assigned to the STA. In some implementations, the disambiguation information may be derived based on the AID value assigned to the STA. For example, a STA assigned to an even AID value may interpret the dRU CSD start index 1236 as pointing to an entry in the upper half of the CSD table, while a STA assigned to an odd AID value may interpret the dRU CSD start index 1236 as pointing to an entry in the lower half of the CSD table.

[0103] The RU allocation information 1233 may be carried within the RU allocation subfield of the user information field 1232 as defined by existing versions of the IEEE 802.11 standard. In other words, the existing RU allocation subfield may be reused to indicate the logical RU associated with the rRU transmission or the dRU transmission. In contrast, the distributed transmission information 1234, the dRU distributed bandwidth information 1235, and the dRU CSD start index 1236 represent new signaling that is not currently included within the existing trigger frame format. The distributed transmission information 1234 may require at least one bit (to indicate an rRU or a dRU), the dRU distributed bandwidth information 1235 may require at least two bits (to indicate a spreading bandwidth of 20 MHz, 40 MHz, or 80 MHz), and the dRU CSD start index 1236 may require at least three bits.

[0104] Aspects of the present disclosure recognize that the trigger frame 1200 may include some reserved bits. The reserved bits represent unused bits that are reserved for future implementations of the IEEE 802.11 standard. For example, one or more reserved bits in a previous version or release of the IEEE 802.11 standard may be repurposed (to carry information) in a later version or release. In some implementations, some reserved bits associated with an existing trigger frame format may be repurposed to carry distributed transmission information 1234, dRU distributed bandwidth information 1235, or dRU CSD start index 1236. As explained above, the new signaling may require at least six total bits to convey.

[0105] FIG. 13 illustrates a user information field 1300 of a trigger frame formatted according to an existing trigger frame format. More specifically, the user information field 1300 conforms to the EHT variant user information field format defined by the initial release of the IEEE 802.11be amendment of the IEEE 802.11 standard. For example, with reference to FIG. 12, the user information field 1300 may be an example of the user information field 1232. Each user information field in the user information list is identified by a respective AID value in the AID12 subfield (in bit positions B0-B11). In some aspects, the AID value may uniquely identify a particular STA (or user) within the BSS.

[0106] The user information field 1300 also includes an RU allocation subfield (in bit positions B12-B19) and a PS160 subfield (in bit position B39). The combined value of the RU allocation subfield and the PS160 subfield is mapped to an entry in an RU allocation table. The RU allocation table is a lookup table that stores a number of entries representing respective RU or MRU allocations. Specifically, each entry in the RU allocation table may indicate a bandwidth, an RU size, and an RU index. In some aspects, the RU allocation subfield may be an example of the RU allocation subfield 1233 of FIG. 12. In some implementations, any entry in the RU allocation table may be allocated for distributed transmission. In some other implementations, only a subset of the entries in the RU allocation table may be allocated for distributed transmission (e.g., 26-tone, 52-tone, 106-tone, 242-tone RUs).

[0107] As shown in FIG. 13, the user information field 1300 includes a reserved bit (at bit position B25). In some aspects, the reserved bit (B25) of the user information field 1300 may be repurposed to carry the distributed transmission information 1234 of FIG. 12. For example, the reserved bit may be replaced by a distributed transmission bit (or subfield) in a future release or version of the IEEE 802.11 standard. More specifically, a first value (e.g., “0”) of the distributed transmission bit may indicate that the logical RU (or MRU) allocated by the RU allocation subfield maps to an rRU. On the other hand, a second value (e.g., “1”) of the distributed transmission bit may indicate that the logical RU (or MRU) allocated by the RU allocation subfield maps to a dRU.

[0108] Aspects of the present disclosure recognize that MU MIMO may not be supported for distributed transmission. Thus, the SS allocation subfield (in bit positions B26-B31) may be diverted to carry dRU-related signaling when the distributed transmission bit indicates that the logical RU maps to the dRU. In some implementations, two bits of the SS allocation subfield may be diverted to carry dRU distributed bandwidth information 1235, three bits of the SS allocation subfield may be diverted to carry dRU CSD start index 1236, and the last remaining bits of the SS allocation subfield may be diverted to carry spatial stream information indicating the number of spatial streams (such as one spatial stream or two spatial streams) assigned to the STA.

[0109] 14 illustrates another example trigger frame 1400 that may be used for communication between an AP and one or more STAs, according to some implementations. The trigger frame 1400 may be used to request a TB PPDU (such as the TB PPDU 1000 of FIG. 10) from one or more STAs. For example, referring to FIG. 1, the AP 102 may transmit the trigger frame 1400 to request a TB PPDU from one or more of the STAs 104. The trigger frame 1400 may allocate resources (such as one or more rRUs or dRUs) for transmission in the TB PPDU.

[0110] The trigger frame 1400 includes a MAC header 1410, a common information field 1420, a user information list 1430, zero or more padding bits 1440, and an FCS 1450. The MAC header 1410 includes a frame control field, a duration field, an RA field, and a TA field. The common information field 1420 and the user information list 1430 carry configuration information that may be used by a receiving device to configure a TB PPDU to be transmitted in response to receiving the trigger frame 1400. In some aspects, the user information list 1430 may include one or more user information fields 1432, each carrying per-user information for a respective user. In contrast, the common information field 1420 may carry information that is common to all recipients of the trigger frame 1400 (e.g., any users identified in the user information list 1430).

[0111] In some implementations, the common information field 1420 may carry a dRU and distributed bandwidth information 1422 indicating whether a logical RU allocated for transmission in a particular bandwidth or sub-band associated with the TB PPDU maps to an rRU or a dRU. The dRU and distributed bandwidth information 1422 may further indicate the spreading bandwidth associated with any dRU allocated for transmission in a given sub-band. In some implementations, the dRU and distributed bandwidth information 1422 may include a 3-bit bitmap for each 80 MHz sub-band associated with the TB PPDU. Each bitmap indicates whether a logical RU associated with an 80 MHz sub-band maps to an rRU or a dRU. · Map to rRU or Either mapped to a dRU spread across the first 20 MHz sub-band, Either mapped to a dRU spread across the first 40 MHz sub-band, Either mapped to a dRU spread over a 40 MHz portion of the 80 MHz sub-band, Either mapped to dRUs spread across the 80MHz sub-band, In addition to the dRU spread over 20 MHz, map to a dRU spread over a 40 MHz portion of the (punctured) 80 MHz subband, or In addition to the dRU spread over 40 MHz, map to a dRU spread over a 20 MHz portion of the (punctured) 80 MHz subband It can be shown that

[0112] Aspects of the present disclosure recognize that 12 bits are required for the dRU and distribution bandwidth information 1422 to cover the entire 320 MHz PPDU bandwidth. However, 12 bits may not be available to be repurposed within the common information field 1420. Thus, in some other implementations, some or all of the dRU and distribution bandwidth information 1422 may be carried within a specific user information field 1438 of the user information list 1430. As described with reference to FIG. 13, each user information field 1432 of the user information list 1430 is identified by an AID value assigned to a particular STA in the BSS. In contrast, the specific user information field 1438 may be identified by an AID value (e.g., 2007) that is not assigned to any STA in the BSS. In some aspects, the specific user information field 1438 may be an extension of the common information field 1420. In other words, the specific user information field 1438 may carry information common to all users associated with the trigger frame.

[0113] In some implementations, each user information field 1432 may carry RU allocation information 1434 and a dRU CSD start index 1436. The RU allocation information 1434 indicates the logical RU (or MRU) that is allocated to the user associated with the user information field 1432. The STA may determine whether the logical RU maps to an rRU or a dRU based on the dRU and distributed bandwidth information 1422. For example, if the logical RU is allocated for transmission in an 80 MHz sub-band designated for the rRU, the STA may determine that the logical RU allocation maps to the rRU. On the other hand, if the logical RU is allocated for transmission in an 80 MHz sub-band designated for the dRU, the STA may determine that the logical RU allocation maps to the dRU. The spreading bandwidth associated with the dRU is further indicated by the dRU and distributed bandwidth information 1422.

[0114] If the dRU and distributed bandwidth information 1422 indicates that the logical RU is a dRU, the dRU CSD start index 1436 can point to a respective entry in a global CSD table that stores a number (N) of global CSD values. In some implementations, the global CSD table (such as the CSD table 1132 in FIG. 11) may store eight global CSD values ​​(N=8). In such implementations, the CSD start index 1436 may be a three-bit value that points to a separate entry in the global CSD table. In some other implementations, the global CSD table may store sixteen global CSD values ​​(N=16). In such implementations, the CSD start index 1436 may be a three-bit value that points to a respective entry in the top half of the global CSD table or a respective entry in the bottom half of the global CSD table. The STA associated with the user information field 1432 may determine whether the dRU CSD start index 1436 points to an entry in the upper half or lower half of the global CSD table based on explicit or implicit disambiguation information (such as that described with reference to FIG. 12).

[0115] The RU allocation information 1434 may be carried in the RU allocation subfield of the user information field 1432, such as that defined by existing versions of the IEEE 802.11 standard. In other words, the existing RU allocation subfield may be reused to indicate the logical RU associated with the rRU or dRU transmission. In contrast, the dRU and distributed bandwidth information 1422 and the dRU CSD start index 1436 represent new signaling that is not currently included in the existing trigger frame format. As explained above, the dRU and distributed bandwidth information 1422 may require at least 12 bits, and the dRU CSD start index 1436 may require at least 3 bits. In some implementations, the dRU CSD start index 1436 may be signaled by repurposing 3 bits of the SS allocation subfield of the user information field 1432 (as explained with reference to FIG. 13 ). In some implementations, the dRU and distribution bandwidth information 1422 may be signaled by repurposing some reserved bits in the common information field 1420 or some reserved bits in the specific user information field 1438.

[0116] FIG. 15 illustrates a common information field 1500 of a trigger frame formatted according to an existing trigger frame format. More specifically, the common information field 1500 conforms to the EHT variant common information field format defined by the initial release of the IEEE 802.11be amendment of the IEEE 802.11 standard. For example, referring to FIG. 14, the common information field 1500 may be an example of the common field 1420. In the example of FIG. 15, the common information field 1500 may be included in a trigger frame that is configured to request an EHT TB PPDU.

[0117] As shown in FIG. 15, the common information field 1500 includes a total of eight reserved bits (in bit positions B56-B62 and B63). In some aspects, any number of the reserved bits may be repurposed to carry at least a portion of the dRU and distributed bandwidth information 1422 of FIG. 14. For example, the reserved bits may be replaced by the dRU and distributed bandwidth subfields in a future release or version of the IEEE 802.11 standard. More specifically, the dRU and distributed bandwidth subfields may include at least three bits representing a bitmap associated with an 80 MHz subband of the PPDU bandwidth (as described with reference to FIG. 14). In some implementations, the dRU and distributed bandwidth subfields may include an additional three bits representing a bitmap associated with another 80 MHz subband of the PPDU bandwidth.

[0118] FIG. 16 illustrates a specific user information field 1600 of a trigger frame formatted according to an existing trigger frame format. More specifically, the specific user information field 1600 conforms to the specific user information field format defined by the initial release of the IEEE 802.11be amendment of the IEEE 802.11 standard. Thus, the AID12 subfield (in bit positions B0-B11) may carry an AID value equal to 2007. For example, referring to FIG. 14, the specific user information field 1600 may be an example of the specific user information field 1438. More specifically, the specific user information field 1600 may be an extension of a common information field (such as the common information field 1420) of the underlying trigger frame.

[0119] As shown in FIG. 16, the special user information field 1600 includes a total of three reserved bits (bit positions B37-B39) and twelve U-SIG ignore and valid bits (bit positions B25-B36). In accordance with the EHT TB PPDU format, the reserved bits are further subdivided into validation bits and ignore bits. The validation bits are used to indicate whether the STA should continue to receive the PPDU, and the ignore bits may be ignored by the receiving STA. In some aspects, any number of the reserved bits may be repurposed to carry at least a portion of the dRU and distributed bandwidth information 1422 of FIG. 14. For example, the reserved bits may be replaced by the dRU and distributed bandwidth subfields in a future release or version of the IEEE 802.11 standard. More specifically, the dRU and distributed bandwidth subfields may include three bits that represent a bitmap associated with the 80 MHz subbands of the PPDU bandwidth (as described with reference to FIG. 14).

[0120] In some other aspects, any number of the U-SIG ignore bits and validation bits may be diverted to carry at least a portion of the dRU and distribution bandwidth information 1422. For example, the U-SIG ignore bits and validation bits may be replaced by the dRU and distribution bandwidth subfields in a future release or version of the IEEE 802.11 standard. More specifically, the dRU and distribution bandwidth subfields may include at least three bits representing a bitmap associated with an 80 MHz subband of the PPDU bandwidth. In some implementations, all twelve U-SIG ignore bits and validation bits may be diverted to carry the dRU and distribution bandwidth information 1422 in its entirety. For example, the dRU and distribution bandwidth subfields may carry four three-bit bitmaps covering all 80 MHz subbands of the 320 MHz PPDU bandwidth. In such implementations, the dRU and distribution bandwidth information 1422 may be carried exclusively within the special user information field 1438 (instead of the common information field 1420).

[0121] 17 illustrates another example trigger frame 1700 that may be used for communication between an AP and one or more STAs, according to some implementations. The trigger frame 1700 may be used to request a TB PPDU (such as the TB PPDU 1000 of FIG. 10) from one or more STAs. For example, referring to FIG. 1, the AP 102 may transmit the trigger frame 1700 to request a TB PPDU from one or more of the STAs 104. The trigger frame 1700 may allocate resources (such as one or more rRUs or dRUs) for transmission in the TB PPDU.

[0122] The trigger frame 1700 includes a MAC header 1710, a common information field 1720, a user information list 1730, zero or more padding bits 1740, and an FCS 1750. The MAC header 1710 includes a frame control field, a duration field, an RA field, and a TA field. The common information field 1720 and the user information list 1730 carry configuration information that may be used by a receiving device to configure a TB PPDU to be transmitted in response to receiving the trigger frame 1700. In some aspects, the user information list 1730 may include one or more user information fields 1732, each carrying per-user information for a respective user. In contrast, the common information field 1720 may carry information that is common to all recipients of the trigger frame 1700 (e.g., any users identified in the user information list 1730).

[0123] In some implementations, the common information field 1720 may carry distributed transmission information 1722 indicating whether a logical RU allocated for transmission within a particular bandwidth or sub-band associated with the TB PPDU maps to an rRU or a dRU. In some implementations, the distributed transmission information 1722 may include a 4-bit bitmap, with each bit corresponding to a respective 80 MHz sub-band associated with the TB PPDU. More specifically, each bit of the bitmap may indicate whether a logical RU associated with a respective 80 MHz sub-band maps to an rRU or a dRU.

[0124] In some implementations, each user information field 1732 may carry RU allocation information 1734, dRU distributed bandwidth information 1736, and dRU CSD start index 1738. The RU allocation information 1734 indicates the logical RU (or MRU) that is allocated to the user associated with the user information field 1732. The STA may determine whether the logical RU maps to an rRU or a dRU based on the distributed transmission information 1722. For example, if the logical RU is allocated for transmission in an 80 MHz sub-band designated for the rRU, the STA may determine that the logical RU assignment maps to the rRU. On the other hand, if the logical RU is allocated for transmission in an 80 MHz sub-band designated for the dRU, the STA may determine that the logical RU assignment maps to the dRU. If the distributed transmission information 1722 indicates that the logical RU is a dRU, the dRU distributed bandwidth information 1736 may indicate a spreading bandwidth associated with the dRU, and the dRU CSD start index 1738 may point to a respective entry in a global CSD table that stores a number (N) of global CSD values.

[0125] In some implementations, the global CSD table (such as CSD table 1132 of FIG. 11) may store eight global CSD values ​​(N=8). In such implementations, the CSD start index 1738 may be a three-bit value that points to a separate entry in the global CSD table. In some other implementations, the global CSD table may store sixteen global CSD values ​​(N=16). In such implementations, the CSD start index 1738 may be a three-bit value that points to a respective entry in the top half of the global CSD table or a respective entry in the bottom half of the global CSD table. The STA associated with the user information field 1732 may determine whether the dRU CSD start index 1738 points to an entry in the top half or the bottom half of the global CSD table based on explicit or implicit disambiguation information (as described with reference to FIG. 12).

[0126] The RU allocation information 1734 may be carried within the RU allocation subfield of the user information field 1732 as defined by existing versions of the IEEE 802.11 standard. In other words, the existing RU allocation subfield may be reused to indicate the logical RU associated with the rRU transmission or the dRU transmission. In contrast, the distributed transmission information 1722, the dRU distributed bandwidth information 1736, and the dRU CSD start index 1738 represent new signaling that is not currently included within the existing trigger frame format. As explained above, the distributed transmission information 1722 may require at least 4 bits, the dRU distributed bandwidth information 1736 may require at least 2 bits (to indicate a spreading bandwidth of 20 MHz, 40 MHz, or 80 MHz), and the dRU CSD start index 1738 may require at least 3 bits.

[0127] In some implementations, the dRU distributed bandwidth information 1736 may be signaled by reusing two bits of the SS allocation subfield of the user information field 1732, and the dRU CSD start index 1738 may be signaled by reusing three bits of the SS allocation subfield (as described with reference to FIG. 13). In some implementations, the distributed transmission information 1722 may be signaled by reusing four reserved bits in the common information field 1720 (as shown in FIG. 15). Still further, in some implementations, the distributed transmission information 1722 may be signaled by reusing any number of reserved bits or U-SIG ignore bits and valid bits in a specific user information field (such as the specific user information field 1600 of FIG. 16) in the user information list 1730.

[0128] 18 shows a flowchart illustrating an example process 1800 of wireless communication supporting global CSD in distributed transmission according to some implementations. In some other implementations, the process 1800 may be performed by a wireless communication device operating as or within a network node, such as one of the STAs 104 or 504 described above with reference to FIG. 1 and FIG. 5B, respectively.

[0129] In some implementations, process 1800 begins at block 1802 with obtaining data for transmission in a PPDU. At block 1804, process 1800 proceeds with modulating data on M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across a wireless channel according to a distributed tone plan, the M tones mapped to the M non-contiguous subcarrier indexes representing dRUs assigned to the wireless communication device. At block 1806, process 1800 proceeds with obtaining a first sequence of values ​​representing an STF of the PPDU based on a bandwidth associated with the wireless channel. At block 1808, process 1800 proceeds with mapping the data and the first sequence of values ​​to one or more spatial streams.

[0130] At block 1810, process 1800 proceeds with applying one or more first CSDs to the sequence of first values ​​mapped to one or more spatial streams, respectively, based on the dRU allocation. In some aspects, the one or more first CSDs may be further applied to the data and LTF of the PPDU mapped to one or more spatial streams, respectively. In some other aspects, one or more second CSDs may be applied to the data and LTF of the PPDU mapped to one or more spatial streams, respectively, where the one or more second CSDs are different from the one or more first CSDs. At block 1812, process 1800 proceeds with transmitting a PPDU including the sequence of first values ​​mapped to one or more spatial streams over a wireless channel.

[0131] In some aspects, the one or more first CSDs may be generated in response to an AID value assigned to the wireless communication device. In some other aspects, the one or more first CSDs may be obtained from a CSD table having a number (N) of entries, each of which indicates a respective CSD associated with a distributed tone plan. In some implementations, N may be equal to 8 or 16.

[0132] In some aspects, the one or more first CSDs may be obtained by calculating a starting index associated with the one or more first CSDs based on information assigned to the wireless communication device, where the allocation starting index points to one of the N entries of the CSD table. In some implementations, the information assigned to the wireless communication device may include at least one of an AID value, an RU allocation index associated with the dRU, or a starting tone offset associated with the dRU. In some implementations, the starting index may be calculated as a modulo operation of the information assigned to the wireless communication device and N.

[0133] In some other aspects, the one or more first CSDs may be obtained from a trigger frame soliciting a PPDU from a wireless communication device, the trigger frame carrying CSD information indicating a starting index associated with the one or more first CSDs, the starting index pointing to one of the N entries of a CSD table. In some implementations, the CSD information may be carried within a user information field associated with the wireless communication device.

[0134] In some aspects, the trigger frame may further carry distributed transmission information indicating that the data is to be transmitted according to the distributed tone plan and may carry dRU distributed bandwidth information indicating a bandwidth associated with the wireless channel. In some implementations, the distributed transmission information and the dRU distributed bandwidth information may be carried in a user information field associated with the wireless communication device. In some other implementations, the distributed transmission information may be carried in a common information field or a specific user information field immediately following the common information field, and the dRU distributed bandwidth information may be carried in a user information field associated with the wireless communication device.

[0135] 19 shows a flowchart illustrating an example process 1900 of wireless communication supporting global CSD in distributed transmission according to some implementations. In some implementations, the process 1900 may be performed by a wireless communication device operating as or within an AP, such as one of the APs 102 or 502, described above with reference to FIG. 1 and FIG. 5A, respectively.

[0136] In some implementations, the process 1900 begins at block 1902 with transmitting a trigger frame requesting a TB PPDU from one or more STAs, the trigger frame carrying first distributed transmission information indicating that a first data portion of the TB PPDU is to be transmitted according to a distributed tone plan and further carrying first dRU distributed bandwidth information indicating a bandwidth of a wireless channel allocated for transmission of the first data portion. At block 1904, the process 1900 proceeds to receive a TB PPDU from the one or more STAs in response to the trigger frame. At block 1906, the process 1900 proceeds to recover the first data portion of the TB PPDU from M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to the distributed tone plan.

[0137] In some implementations, the first distributed transmission information and the first dRU distributed bandwidth information may be carried in a user information field associated with a first STA of the one or more STAs. In some other implementations, the first distributed transmission information may be carried in a common information field or a specific user information field immediately following the common information field, and the first dRU distributed bandwidth information may be carried in a user information field associated with the first STA of the one or more STAs.

[0138] In some implementations, the trigger frame may further carry second distributed transmission information indicating that the second data portion of the TB PPDU is to be transmitted according to a distributed tone plan and may carry second dRU distributed bandwidth information indicating that the bandwidth of the wireless channel is allocated for transmission of the second data portion. In some implementations, the first data portion may be received on one or more first spatial streams and the second data portion may be received on one or more second spatial streams, and the TB PPDU further includes an STF carrying a sequence of first values ​​being received on each of the one or more first spatial streams and each of the one or more second spatial streams.

[0139] In some aspects, the sequence of first values ​​received on one or more first spatial streams may be delayed by one or more first CSDs, respectively, and the sequence of first values ​​received on one or more second spatial streams may be delayed by one or more second CSDs, respectively. In some implementations, the trigger frame may further carry first CSD information indicating a first starting index associated with one or more first CSDs, and may carry second CSD information indicating a second starting index associated with one or more second CSDs, where the first starting index points to a first entry of a CSD table having a number (N) of entries, each of which indicates a respective CSD associated with the distributed tone plan, and the second starting index points to a second entry of the CSD table different from the first entry. In some implementations, N may be equal to 8 or 16. In some implementations, the first CSD information may be carried in a user information field associated with a first STA of the one or more STAs, and the second CSD information may be carried in a user information field associated with a second STA of the one or more STAs.

[0140] In some implementations, the TB PPDU may further include an LTF carrying a sequence of second values ​​received on each of the one or more first spatial streams and a sequence of third values ​​received on each of the one or more second spatial streams, where the first data portion and the sequence of second values ​​received on the one or more first spatial streams are delayed by one or more first CSDs, respectively, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are delayed by one or more second CSDs, respectively.

[0141] In some other implementations, the TB PPDU may further include an LTF carrying a sequence of second values ​​being received on each of the one or more first spatial streams and a sequence of third values ​​being received on each of the one or more second spatial streams, where the first data portion and the sequence of second values ​​received on the one or more first spatial streams are each delayed by one or more third CSDs different from the one or more first CSDs, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are each delayed by one or more fourth CSDs different from the one or more second CSDs.

[0142] Figure 20 shows a block diagram of an example wireless communication device 2000 according to some implementations. In some implementations, the wireless communication device 2000 is configured to perform the process 1800 described above with reference to Figure 18. The wireless communication device 2000 may be an example implementation of the wireless communication device 400 described above with reference to Figure 4. For example, the wireless communication device 2000 may be a chip, SoC, chipset, package, or device including at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0143] The wireless communication device 2000 includes a receiving component 2010, a communications manager 2020, and a transmitting component 2030. The communications manager 2020 further includes a data collection component 2021, a modulation component 2022, an STF determination component 2023, a spatial stream (SS) mapping component 2024, and a CSD component 2025. One or more portions of the components 2021-2025 may be implemented at least in part in hardware or firmware. In some implementations, at least some of the components 2021, 2022, 2023, 2024, or 2025 are implemented at least in part as software stored in a memory (such as memory 408). For example, one or more portions of the components 2021-2025 may be implemented as non-transitory instructions (or "code") executable by a processor (such as processor 406) to perform the functions or operations of the respective components.

[0144] The receiving component 2010 is configured to receive RX signals from one or more other wireless communication devices over a wireless channel. The communications manager 2020 is configured to control or manage communications with one or more other wireless communication devices. In some implementations, the data collection component 2021 may obtain data for transmission in the PPDU, the modulation component 2022 may modulate data on M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to a distributed tone plan, the M tones mapped to the M non-contiguous subcarrier indexes representing dRUs assigned to the wireless communication device, the STF determination component 2023 may obtain a sequence of values ​​representing the STF of the PPDU based on a bandwidth associated with the wireless channel, the SS mapping component 2024 may map the data and the sequence of values ​​to one or more spatial streams, and the CSD component 2025 may apply one or more CSDs to the sequence of values ​​mapped to the one or more spatial streams, respectively, based on the dRU assignment. The transmission component 2030 is configured to transmit a TX signal to one or more other wireless communication devices via the wireless channel. In some implementations, the transmitting component 2030 may transmit a PPDU including a sequence of values ​​mapped to one or more spatial streams over a wireless channel.

[0145] Figure 21 shows a block diagram of an example wireless communication device 2100 according to some implementations. In some implementations, the wireless communication device 2100 is configured to perform the process 1900 described above with reference to Figure 19. The wireless communication device 2100 may be an example implementation of the wireless communication device 400 described above with reference to Figure 4. For example, the wireless communication device 2100 may be a chip, SoC, chipset, package, or device including at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0146] The wireless communication device 2100 includes a receiving component 2110, a communications manager 2120, and a transmitting component 2130. The communications manager 2120 further includes a dRU demapping component 2122. Portions of the dRU demapping component 2122 may be implemented at least in part in hardware or firmware. In some implementations, the dRU demapping component 2122 is implemented at least in part as software stored in a memory (such as the memory 408). For example, portions of the dRU demapping component 2122 may be implemented as non-transitory instructions (or “code”) executable by a processor (such as the processor 406) to perform the functions or operations of the respective components.

[0147] The receiving component 2110 is configured to receive RX signals from one or more other wireless communication devices over a wireless channel, and the transmitting component 2130 is configured to transmit TX signals to one or more other wireless communication devices over a wireless channel. In some implementations, the transmitting component 2130 may transmit a trigger frame requesting a TB PPDU from one or more STAs, the trigger frame carrying distributed transmission information indicating that a data portion of the TB PPDU will be transmitted according to a distributed tone plan, and further carrying dRU distributed bandwidth information indicating a bandwidth of a wireless channel allocated for transmission of the first data portion. In some implementations, the receiving component 2110 may receive the TB PPDU from one or more STAs in response to the trigger frame. The communications manager 2120 is configured to control or manage communications with one or more other wireless communication devices. In some implementations, the dRU demapping component 2122 can recover the data portion of the TB PPDU from M tones mapped to a number (M) of non-contiguous subcarrier indexes among a plurality of subcarrier indexes across the wireless channel according to a distributed tone plan.

[0148] The following numbered clauses describe example implementations. 1. A method of wireless communication by a wireless communication device, comprising: Obtaining data regarding a transmission in a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU); modulating data on M tones mapped to a number (M) of non-contiguous subcarrier indexes of a plurality of subcarrier indexes across the wireless channel in accordance with a distributed tone plan, the M tones mapped to the M non-contiguous subcarrier indexes representing distributed resource units (dRUs) assigned to the wireless communication device; obtaining a first sequence of values ​​representing a short training field (STF) of the PPDU based on a bandwidth associated with the wireless channel; mapping the data and the first sequence of values ​​into one or more spatial streams; applying one or more first cyclic shift delays (CSDs) to the sequence of first values ​​mapped to the one or more spatial streams, respectively, based on the dRU allocation; transmitting, via a wireless channel, a PPDU including the first sequence of values ​​mapped to one or more spatial streams; A method comprising: 2. obtaining a second sequence of values ​​representing a long training field (LTF) of the PPDU; mapping the second sequence of values ​​into one or more spatial streams; applying one or more first CSDs to the data mapped to the one or more spatial streams and to the second sequence of values, respectively; 2. The method of claim 1, further comprising: 3. obtaining a second sequence of values ​​representing the LTF of the PPDU; mapping the second sequence of values ​​into one or more spatial streams; 2. The method of claim 1, further comprising applying one or more second CSDs to the data mapped to the one or more spatial streams and the sequence of second values, respectively, wherein the one or more second CSDs are different from the one or more first CSDs. 4. Generating one or more first CSDs in response to an association identifier (AID) value assigned to the wireless communication device. 4. The method of any of clauses 1 to 3, further comprising: 5. Obtaining one or more first CSDs from a CSD table having a number (N) of entries, each entry indicating a respective CSD associated with the distributed tone plan. 4. The method of any one of clauses 1 to 3, further comprising: 6. The method of any one of clauses 1 to 3 or 5, wherein N is equal to 8 or 16. 7. Acquiring one or more first CSDs: The method of any one of clauses 1 to 3, 5 or 6, comprising calculating a starting index associated with one or more first CSDs based on information assigned to the wireless communication device, the starting index pointing to one of the N entries in the CSD table. 8. The method of any one of clauses 1 to 3 or 5 to 7, wherein the information assigned to the wireless communications device includes at least one of an AID value, a resource unit (RU) allocation index associated with the dRU, or a starting tone offset associated with the dRU. 9. The method of any one of clauses 1 to 3 or 5 to 8, wherein the starting index is calculated modulo N and the information assigned to the wireless communication device. 10. receiving a trigger frame requesting a PPDU from a wireless communication device, the trigger frame carrying CSD information indicating a starting index associated with one or more first CSDs, the starting index pointing to one of N entries in a CSD table; 7. The method of any one of clauses 1 to 3, 5 or 6, further comprising: 11. The method of any one of clauses 1 to 3, 5, 6, or 10, wherein the CSD information is carried within a user information field associated with the wireless communication device. 12. The method of any one of clauses 1 to 3, 5, 6, 10, or 11, wherein the trigger frame further carries distributed transmission information indicating that the data will be transmitted according to a distributed tone plan, and carries dRU distributed bandwidth information indicating a bandwidth associated with the wireless channel. 13. The method of any one of clauses 1-3, 5, 6, or 10-12, wherein the distributed transmission information and the dRU distributed bandwidth information are carried within a user information field associated with the wireless communication device. 14. The method of any one of clauses 1 to 3, 5, 6, or 10 to 12, wherein the distributed transmission information is carried in a common information field or a specific user information field immediately following the common information field, and the dRU distributed bandwidth information is carried in a user information field associated with the wireless communications device. 15. At least one processor; at least one memory communicatively coupled to the at least one processor and storing processor-readable code; 1. A wireless communication device comprising: 15. A wireless communications device comprising: a first communication module configured to receive and transmit data from a first communication port of a first sub-processor; 16. A method of wireless communication implemented by a wireless communication device, comprising: transmitting a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) from one or more wireless stations (STAs), the trigger frame carrying first distributed transmission information indicating that a first data portion of the TB PPDU is to be transmitted according to a distributed tone plan and further carrying first distributed resource unit (dRU) distributed bandwidth information indicating a bandwidth of a wireless channel allocated for transmission of the first data portion; receiving a TB PPDU from one or more STAs in response to the trigger frame; recovering a first data portion of the TB PPDU from M tones mapped to a number (M) of non-consecutive subcarrier indexes of a plurality of subcarrier indexes across the wireless channel according to a distributed tone plan; A method comprising: 17. The method of clause 16, wherein the first distributed transmission information and the first dRU distributed bandwidth information are carried in a user information field associated with a first STA of the one or more STAs. 18. The method of clause 16, wherein the first distributed transmission information is carried in a common information field or a specific user information field immediately following the common information field, and the first dRU distributed bandwidth information is carried in a user information field associated with a first STA of the one or more STAs. 19. The method of any one of clauses 16 to 18, wherein the trigger frame further carries second distributed transmission information indicating that a second data portion of the TB PPDU is to be transmitted according to a distributed tone plan, and carries second dRU distributed bandwidth information indicating that bandwidth of the wireless channel has been allocated for the transmission of the second data portion. 20. The method of any one of clauses 16 to 19, wherein a first data portion is received on one or more first spatial streams and a second data portion is received on one or more second spatial streams, and the TB PPDU further includes a short training field (STF) carrying a sequence of first values ​​received on each of the one or more first spatial streams and each of the one or more second spatial streams. 21. A method according to any one of clauses 16 to 20, wherein a sequence of first values ​​received on one or more first spatial streams are each delayed by one or more first cyclic shift delays (CSDs), and a sequence of first values ​​received on one or more second spatial streams are each delayed by one or more second CSDs. 22. The method of any one of clauses 16 to 21, wherein the trigger frame further carries first CSD information indicating a first starting index associated with one or more first CSDs and carries second CSD information indicating a second starting index associated with one or more second CSDs, the first starting index pointing to a first entry in a CSD table having a number (N) of entries each indicating a respective CSD associated with the distributed tone plan, and the second starting index pointing to a second entry in the CSD table that is different from the first entry. 23. The method of any one of clauses 16 to 22, wherein N is equal to 8 or 16. 24. A method according to any one of clauses 16 to 23, wherein the first CSD information is carried in a user information field associated with a first STA of the one or more STAs, and the second CSD information is carried in a user information field associated with a second STA of the one or more STAs. 25. The method of any one of clauses 16 to 24, wherein the TB PPDU further includes a long training field (LTF) carrying a sequence of second values ​​received on each of the one or more first spatial streams and a sequence of third values ​​received on each of the one or more second spatial streams, wherein the first data portion and the sequence of second values ​​received on the one or more first spatial streams are delayed by one or more first CSDs, respectively, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are delayed by one or more second CSDs, respectively. 26. The method of any one of clauses 16 to 24, wherein the TB PPDU further includes an LTF carrying a sequence of second values ​​received on each of the one or more first spatial streams and a sequence of third values ​​received on each of the one or more second spatial streams, wherein the first data portion and the sequence of second values ​​received on the one or more first spatial streams are respectively delayed by one or more third CSDs different from the one or more first CSDs, and the second data portion and the sequence of third values ​​received on the one or more second spatial streams are respectively delayed by one or more fourth CSDs different from the one or more second CSDs. 27. At least one processor; at least one memory communicatively coupled to the at least one processor and storing processor-readable code; 1. A wireless communication device comprising: 27. A wireless communications device comprising: a processor-readable code configured, when executed by at least one processor, to perform any one or more of the methods of clauses 16 to 26.

[0149] As used herein, phrases referring to "at least one of" or "one or more of" a list of items refer to any combination of those items, including single elements. For example, "at least one of a, b, or c" is intended to encompass the possibilities of a only, b only, c only, 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.

[0150] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and structural equivalents thereof. The interchangeability of hardware, firmware, and software has been described generally in terms of functionality and illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is performed in hardware, firmware, or software depends on the particular application and design constraints imposed on the overall system.

[0151] Various modifications of the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the present disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and novel features disclosed herein.

[0152] In addition, various features described herein 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, although features may be described above as working in a particular combination and may even initially be claimed as such, in some cases one or more features from the claimed combination may be deleted from the combination, and the claimed combination may be directed to a subcombination or a variation of the subcombination.

[0153] Similarly, although operations are shown in the figures in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order shown, or that all of the operations shown be performed, to achieve a desired result. Furthermore, the figures may generally illustrate another exemplary process in the form of a flow chart or flow diagram. However, other operations not shown may be incorporated into the generally illustrated exemplary process. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the program components and systems described may generally be integrated together in a single software product or packaged in multiple software products.

Claims

1. 1. A method of wireless communication implemented by a wireless communication device, comprising: Obtaining data for transmission in a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU); modulating the data on M tones mapped to a number (M) of non-contiguous subcarrier indices of a plurality of subcarrier indices across a wireless channel in accordance with a distributed tone plan, wherein the M tones mapped to the M non-contiguous subcarrier indices represent distributed resource units (dRUs) assigned to the wireless communication device; obtaining a first sequence of values representing a short training field (STF) of the PPDU based on a bandwidth associated with the wireless channel; mapping the data and the sequence of first values to one or more spatial streams; applying one or more first cyclic shift delays (CSDs) to the sequence of first values mapped to the one or more spatial streams, respectively, based on the dRU assignment; transmitting, via the wireless channel, the PPDU including the sequence of first values mapped to the one or more spatial streams; A method comprising:

2. obtaining a second sequence of values representing a long training field (LTF) of the PPDU; mapping the sequence of second values to the one or more spatial streams; applying the one or more first CSDs to the data mapped to the one or more spatial streams and the sequence of second values, respectively; The method of claim 1 further comprising:

3. obtaining a second sequence of values representing an LTF of the PPDU; mapping the sequence of second values to the one or more spatial streams; and applying one or more second CSDs to the data mapped to the one or more spatial streams and the sequence of second values, respectively, wherein the one or more second CSDs are different from the one or more first CSDs.

4. generating the one or more first CSDs in response to an association identifier (AID) value assigned to the wireless communication device; The method of claim 1 further comprising:

5. Obtaining the one or more first CSDs from a CSD table having a number (N) of entries, each entry indicating a respective CSD associated with the distributed tone plan. The method of claim 1 further comprising:

6. The method of claim 5 , wherein N is equal to 8 or 16.

7. obtaining the one or more first CSDs; 6. The method of claim 5, comprising: calculating a starting index associated with the one or more first CSDs based on information assigned to the wireless communication device, wherein the starting index points to one of the N entries in the CSD table.

8. 8. The method of claim 7, wherein the information assigned to the wireless communication device includes at least one of an AID value, a resource unit (RU) allocation index associated with the dRU, or a starting tone offset associated with the dRU.

9. 10. The method of claim 8, wherein the starting index is calculated modulo N and the information assigned to the wireless communication device.

10. 6. The method of claim 5, further comprising receiving a trigger frame from the wireless communication device requesting the PPDU, the trigger frame carrying CSD information indicating a starting index associated with the one or more first CSDs, the starting index pointing to one of the N entries in the CSD table.

11. 11. The method of claim 10, wherein the CSD information is carried within a user information field associated with the wireless communication device.

12. 11. The method of claim 10, wherein the trigger frame further carries distributed transmission information indicating that the data will be transmitted according to the distributed tone plan, and carries dRU distributed bandwidth information indicating the bandwidth associated with the wireless channel.

13. the distributed transmission information and the dRU distributed bandwidth information are carried within a user information field associated with the wireless communication device; or 13. The method of claim 12, wherein the distributed transmission information is carried in a common information field or a specific user information field immediately following the common information field, and the dRU distributed bandwidth information is carried in a user information field associated with the wireless communication device.

14. at least one processor; at least one memory communicatively coupled to the at least one processor and storing processor-readable code; 1. A wireless communication device comprising: The processor-readable code, when executed by the at least one processor, Obtaining data for transmission in a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU); modulating the data on M tones mapped to a number (M) of non-contiguous subcarrier indices of a plurality of subcarrier indices across a wireless channel in accordance with a distributed tone plan, wherein the M tones mapped to the M non-contiguous subcarrier indices represent distributed resource units (dRUs) assigned to the wireless communication device; obtaining a sequence of values representing a short training field (STF) of the PPDU based on a bandwidth associated with the wireless channel; mapping said sequence of said data and values into one or more spatial streams; applying one or more cyclic shift delays (CSDs) to the sequence of values mapped to the one or more spatial streams, respectively, based on the dRU assignment; transmitting the PPDU over the wireless channel, the PPDU including the sequence of values mapped to the one or more spatial streams.

1. A wireless communication device configured to:

15. Execution of the processor-readable code includes: generating the one or more CSDs in response to an Association Identifier (AID) value assigned to the wireless communication device; or Execution of the processor-readable code includes: calculating a starting index associated with the one or more first CSDs based on information assigned to the wireless communication device; Retrieving the one or more first CSDs from a CSD table having a number (N) of entries, each entry indicating a respective CSD associated with the distribution tone plan, based on the starting index, wherein the starting index points to one of the N entries in the CSD table; or Execution of the processor-readable code includes: receiving a trigger frame from the wireless communication device requesting the PPDU, the trigger frame carrying CSD information indicating a starting index associated with the one or more first CSDs; 15. The wireless communication device of claim 14, further configured: to obtain the one or more first CSDs from a CSD table having a number (N) of entries, each entry indicating a respective CSD associated with the distribution tone plan, based on the starting index, wherein the starting index points to one of the N entries in the CSD table.

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