Downsizing resource units (RU)

Abstract

The present disclosure provides a method, device, and system for requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU). Some implementations relate more specifically to a trigger frame and PPDU design that supports RU downsizing. For example, an access point (AP) may transmit a trigger frame to a wireless station (STA) requesting a TB PPDU. In some aspects, the trigger frame may carry RU allocation information indicating an allocated RU or MRU (associated with a wireless medium) and downsizing information indicating whether downsizing of the RU or MRU is permitted. If interference is detected in a portion of the wireless medium and downsizing is permitted, the STA may transmit the TB PPDU in a downsized RU or MRU. The downsized RU or MRU includes a subset of tones in the RU or MRU allocated by the trigger frame.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to U.S. patent application Ser. No. 17 / 233,242, entitled “RESOURCE UNIT (RU) DOWNSIZING,” filed April 16, 2021, which is assigned to the assignee of this patent application. The disclosures of all prior applications are deemed to be part of, and are incorporated by reference into, this patent application.

[0002] The present disclosure relates generally to wireless communications, and more particularly to downsizing resource units (RUs) used in wireless communications. [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 that conforms to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards 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] Existing versions of the IEEE 802.11 standard support trigger-based uplink communications. In particular, the IEEE 802.11ax amendment of the IEEE 802.11 standard defines a trigger frame format that may be used to request one or more STAs to transmit a trigger-based (TB) physical layer convergence protocol (PLCP) data unit (PPDU). The trigger frame allocates resources to one or more STAs for transmission of the TB PPDU and indicates how the TB PPDU should be configured for transmission. For example, the trigger frame may indicate resource units (RUs) allocated for transmission in the TB PDDU. The RUs represent a set of tones or subcarriers across the wireless channel over which the TB PPDU should be transmitted. However, the TB PPDU cannot be transmitted according to existing versions of the IEEE 802.11 standard if any portion of the wireless channel is busy or otherwise unavailable.

[0005] For example, new WLAN communication protocols are being developed to enable enhanced WLAN communication features, such as increased bandwidth and support for multiple resource unit (MRU) allocation. As a result, the trigger frame can allocate a larger RU (or MRU) to the TB PPDU. Increasing the bandwidth of the wireless channel also increases the likelihood of interference in any part of the wireless channel. Therefore, new trigger frame and PPDU formats are needed to provide greater flexibility in medium utilization. Summary of the Invention [Means for solving the problem]

[0006] The systems, methods, and devices of the present disclosure each have several innovative aspects, no one of which is solely responsible for the desirable attributes disclosed herein.

[0007] One innovative aspect of the subject matter described in this disclosure may be implemented as a method of wireless communication. The method may be executed by a wireless communication device and may include receiving a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) from the wireless communication device, the trigger frame carrying resource unit (RU) allocation information indicating a plurality of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the plurality of tones is allowed, the plurality of tones representing a first RU or a first plurality of resource units (MRUs) associated with a wireless medium, determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of the wireless medium where interference is present, and selectively transmitting the TB PPDU on a subset of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU. In some aspects, the downsizing information may be indicated by the value of the downsizing bit in the user information field. In some other aspects, the RU allocation information and the downsizing information are jointly indicated by the value of the RU allocation subfield of the user information field.

[0008] In some implementations, the method further includes receiving RU guarantee information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU, and selecting a subset of tones to exclude one or more unavailable tones and include at least one or more guaranteed tones. In some aspects, the RU guarantee information may be carried in a common information field preceding a user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame. In some other aspects, the RU guarantee information may be carried in a special user information field of the trigger frame, the special user information field being identified by an association identifier (AID) value not assigned to any wireless communication device associated with the same basic service set (BSS) as the wireless communication device. Still further, in some aspects, the RU guarantee information may be carried in a management frame received before the trigger frame.

[0009] In some implementations, the RU guarantee information may include a bitmap, with each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 20 MHz subchannels of the respective 80 MHz channel are associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 40 MHz subchannels of the respective 160 MHz channel are associated with one or more guaranteed tones. Still further, in some implementations, the RU guarantee information may be mapped to one of a number of entries in a look-up table (LUT), with each entry in the LUT indicating a respective combination of one or more subchannels of the wireless channel associated with one or more guaranteed tones.

[0010] In some implementations, the TB PPDU may include a physical layer preamble with a universal signal field (U-SIG) carrying downsized signaling information indicating a subset of tones. In some aspects, the downsized signaling information may be mapped to one of a plurality of entries in a LUT, with each entry in the LUT indicating a respective RU or MRU. In some other aspects, the downsized signaling information may indicate a remaining tone of the plurality of tones not included in the subset, with the remaining tone representing a third RU or a third MRU.

[0011] 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 modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. In some implementations, execution of the processor readable code by the at least one processor causes the wireless communication device to perform operations including receiving a trigger frame from the wireless communication device requesting a TB PPDU, the trigger frame carrying RU allocation information indicating a plurality of tones allocated for the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the plurality of tones is allowed, the plurality of tones representing a first RU or a first MRU associated with the wireless medium; determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of the wireless medium where interference is present; and selectively transmitting the TB PPDU on a subset of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU.

[0012] Another innovative aspect of the subject matter described in this disclosure may be implemented as a method of wireless communication. The method may be executed by a wireless communication device and may include transmitting a trigger frame requesting a TB PPDU, the trigger frame carrying RU allocation information indicating a plurality of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating that downsizing of the plurality of tones is permitted, the plurality of tones representing a first RU or a first MRU, and receiving the TB PPDU on a subset of tones of the plurality of tones in response to the trigger frame, the subset of tones representing a second RU or a second MRU smaller than the first RU or the first MRU. In some aspects, the downsizing information may be indicated by a value of a downsizing bit in the user information field. In some other aspects, the RU allocation information and the downsizing information are jointly indicated by a value of a RU allocation subfield of the user information field.

[0013] In some implementations, the method further includes transmitting RU allocation information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU, the subset of tones including at least one or more guaranteed tones. In some aspects, the RU guarantee information may be carried in a common information field preceding a user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame. In some other aspects, the RU guarantee information may be carried in a special user information field of the trigger frame, the special user information field being identified by an AID value not assigned to any wireless communication device associated with the wireless communication device. Still further, in some aspects, the RU guarantee information may be carried in a management frame transmitted before the trigger frame.

[0014] In some implementations, the RU guarantee information may include a bitmap, with each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with one or more guaranteed tones. Still further, in some implementations, the RU guarantee information may be mapped to one of a number of entries in a LUT, with each entry in the LUT indicating a respective combination of one or more subchannels of the wireless channel associated with one or more guaranteed tones.

[0015] In some implementations, the TB PPDU may include a physical layer preamble with a U-SIG carrying downsized signaling information indicating a subset of tones. In some aspects, the downsized signaling information may be mapped to one of a plurality of entries in a LUT, with each entry in the LUT indicating a respective RU or MRU. In some other aspects, the downsized signaling information may indicate a remaining tone of the plurality of tones not included in the subset, with the remaining tone representing a third RU or a third MRU.

[0016] 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 modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor that stores the processor-readable code. In some implementations, execution of the processor-readable code by the at least one processor causes the wireless communication device to perform operations including: transmitting a trigger frame requesting a TB PPDU, the trigger frame carrying RU allocation information indicating a plurality of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating downsizing of the plurality of tones is allowed, the plurality of tones representing a first RU or a first MRU; and receiving the TB PPDU on a subset of the plurality of tones in response to the trigger frame, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU.

[0017] 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]

[0018] [Figure 1] 1 is a pictorial diagram of an example wireless communication network. [Figure 2A] 1 illustrates an example protocol data unit (PDU) that may be used for communication between an access point (AP) and one or more wireless stations (STAs). [Figure 2B] FIG. 2B illustrates example fields in 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] FIG. 1 is a block diagram of an example wireless communication device. [Figure 5A] FIG. 2 is a block diagram of an example AP. [Figure 5B] 1 is a block diagram of an exemplary STA. [Figure 6] A diagram showing an example trigger frame that can be used for communication between an AP and several STAs according to some implementations. [Figure 7] FIG. 2 illustrates an exemplary user information field of a trigger frame formatted according to an existing trigger frame format. [Figure 8] 1 is a frequency diagram illustrating an example resource allocation of a wireless channel, according to some implementations. [Figure 9] A frequency diagram illustrating an example resource allocation for a wireless channel including a guaranteed sub-channel, according to some implementations. [Figure 10] A diagram showing another example trigger frame that can be used for communication between an AP and a number of STAs, according to some implementations. [Figure 11] FIG. 2 illustrates a common information field of a trigger frame formatted according to an existing trigger frame format. [Figure 12] A diagram showing another example trigger frame that can be used for communication between an AP and a number of STAs, according to some implementations. [Figure 13] FIG. 2 illustrates a special user information field of a trigger frame formatted according to an existing trigger frame format. [Figure 14] A diagram showing an example trigger-based (TB) PPDU that can be used for communication between a STA and an AP according to some implementations. [Figure 15]A diagram showing a universal signal field (U-SIG) of a PPDU formatted according to an existing PPDU format. [Figure 16] 1 is a sequence diagram illustrating an example message exchange between an AP and a STA in a wireless network. [Figure 17] 1 is a flowchart illustrating an example process for wireless communication supporting resource unit (RU) downsizing, according to some implementations. [Figure 18] 1 is a flowchart illustrating an example process for wireless communication to support RU downsizing, according to some implementations. [Figure 19] FIG. 1 is a block diagram of an example wireless communication device, according to some implementations. [Figure 20] FIG. 1 is a block diagram of an example wireless communication device, according to some implementations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Like reference numbers and designations in the various drawings indicate like elements.

[0020] 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 implemented 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 as 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 implemented 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 implemented using other wireless communications protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN), wireless local area network (WLAN), wireless wide area network (WWAN), or internet of things (IOT) network.

[0021] Various aspects relate generally to trigger-based communication supporting new wireless communication protocols, and more particularly to trigger frame and physical layer convergence protocol (PLCP) protocol data unit (PPDU) designs supporting resource unit (RU) downsizing. As used herein, the term "RU downsizing" refers to transmission of a TB PPDU across an RU or multiple RUs (MRUs) smaller than the RU or MRU initially allocated in the TB PPDU. For example, an access point (AP) may transmit a trigger frame to a wireless station (STA) requesting a TB PPDU. In some aspects, the trigger frame may carry RU allocation information indicating an allocated RU or MRU (associated with a wireless medium) and downsizing information indicating whether downsizing of the RU or MRU is permitted. If interference is detected in a portion of the wireless medium (e.g., due to the medium being busy) and downsizing is permitted, the STA may transmit a TB PPDU on a tone (or "subcarrier") spanning the downsized RU or MRU. The downsized RU or MRU includes a subset of the tones in the RU or MRU allocated by the trigger frame. In some aspects, the downsized RU or MRU may be required to include one or more guaranteed tones. The guaranteed tones span a portion of the wireless medium where the AP expects to receive signaling for the TB PPDU, such as, for example, a physical layer (PHY) preamble. Thus, in some aspects, the STA may provide signaling for the downsized RU or MRU in the PHY preamble of the TB PPDU.

[0022] Particular implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages: RU downsizing provides greater flexibility in medium utilization for trigger-based communications. By allowing STAs to transmit TB PPDUs on a subset of tones allocated by trigger frames, aspects of the present disclosure may support increased network throughput achievable in accordance with the IEEE 802.11be amendment and future generations of the IEEE 802.11 standard. For example, if only a portion of the wireless medium is busy or unavailable, the STA may transmit TB PPDUs on tones spanning downsized RUs or MRUs that avoid the busy portion. As a result, the TB PPDUs may adapt to the conditions of the wireless medium. By requiring that the downsized RUs or MRUs include one or more guaranteed tones, aspects of the present disclosure may ensure that the AP can detect the TB PPDU and recover the information carried therein. For example, the PHY preamble of the TB PPDU may be decoded in its entirety from the guaranteed tones. Thus, by signaling the downsized RU or MRU in the PHY preamble, aspects of the present disclosure may ensure that the AP can identify the downsized RU or MRU in the TB PPDU by observing only the guaranteed tones.

[0023] 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 (hereinafter referred to as WLAN 100). For example, the WLAN 100 may be a network implementing at least one of the IEEE 802.11 wireless communication protocol standards (such as those defined by the IEEE 802.11-2016 specification or amendments thereto, 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 a number of 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 also include multiple APs 102.

[0024] 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.

[0025] A single AP 102 and an associated set of STAs 104 may be referred to as a basic service set (BSS) managed by the respective AP 102. FIG. 1 additionally shows an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. The BSS may be identified to users by a service set identifier (SSID) and to other devices by a basic service set identifier (BSSID), which may be a 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 or maintain a respective communication link 108 (hereinafter also referred to as a "Wi-Fi link") with the AP 102. For example, the beacon may include an identification of the primary channel used by each AP 102, as well as timing synchronization functionality for establishing or maintaining timing synchronization with the AP 102. The APs 102 may provide access to external networks to various STAs 104 within the WLAN via their respective communication links 108.

[0026] The APs 102 and the STAs 104 can function and communicate (via their respective communication links 108) in accordance with the IEEE 802.11 wireless communications protocol standards family (such as those defined by the IEEE 802.11-2016 specification or amendments thereto, including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be). These standards define WLAN radios and baseband protocols for the PHY and Medium Access Control (MAC) layers. The APs 102 and the STAs 104 send 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 APs 102 and STAs 104 in the WLAN 100 may transmit PPDUs over an unlicensed spectrum, which may be a portion of the 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 APs 102 and 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 APs 102 and STAs 104 may also be configured to communicate over other frequency bands, such as shared licensed frequency bands, where multiple operators may have licenses to operate in the same or overlapping frequency band or bands.

[0027] Access to the shared wireless medium is generally managed by a distributed coordination function (DCF). With DCF, there is generally no centralized master device that allocates time and frequency resources of the shared wireless medium. In contrast, wireless communication devices, such as the AP 102 or the STA 104, must wait for a certain time and then contend for access to the wireless medium before being allowed to transmit data. In some implementations, the wireless communication devices may be configured to implement DCF by using a carrier sense multiple access (CSMA) / collision avoidance (CA) (CSMA / CA) technique and timing intervals. Before transmitting data, the wireless communication devices may perform clear channel assessment (CCA) and determine that a suitable wireless channel is idle. CCA includes both physical (PHY-level) carrier sensing and virtual (MAC-level) carrier sensing. Physical carrier sensing is accomplished by measuring the received signal strength of a valid frame, which is then compared to a threshold to determine whether the channel is busy. For example, if the received signal strength of a detected preamble is above a threshold, the medium is considered busy. Physical carrier sensing also includes energy detection. Energy detection involves measuring the total energy received by a wireless communication device, regardless of whether the received signal represents a valid frame. If the detected total energy is above a threshold, the medium is considered busy. Virtual carrier sensing is achieved by using a network allocation vector (NAV), which is an indicator of the time when the medium may next be idle. The NAV is reset each time a valid frame not addressed to the wireless communication device is received. The NAV effectively serves as a duration that must elapse before the wireless communication device can contend for access, even if there are no detected symbols or the detected energy is below an associated threshold.

[0028] Some APs and STAs may be configured to implement spatial reuse techniques. For example, APs and STAs configured for communication using IEEE 802.11ax or 802.11be may be configured with BSS colors. APs associated with different BSSs may be associated with different BSS colors. If an AP or STA detects a wireless packet from another wireless communication device while contending for access, the AP or STA may apply different contention parameters based on whether the wireless packet is transmitted to or from another wireless communication device in its BSS or a wireless communication device from an overlapping BSS (OBSS), as determined by a BSS color indication in the preamble of the wireless packet. For example, if the BSS color associated with the wireless packet is the same as the BSS color of the AP or STA, the AP or STA may use a first received signal strength indication (RSSI) detection threshold when performing CCA for the wireless channel. However, if the BSS color associated with the wireless packet is different from the BSS color of the AP or STA, the AP or STA may use a second RSSI detection threshold instead of using the first RSSI detection threshold when performing CCA on the wireless channel, where the second RSSI detection threshold is greater than the first RSSI detection threshold. In this way, the requirement to win contention is relaxed when the interfering transmission is associated with the OBSS.

[0029] 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 including 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.

[0030] 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 upper layer data, for example in the form of a Medium Access Control (MAC) Protocol Data Unit (MPDU) or an Aggregated MPDU (A-MPDU).

[0031] 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 bits 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 utilize the data rate and length indicated in the data rate field 222 and the length field 226 to determine the time length of the packet, e.g., in units of microseconds (μs) or other time units.

[0032] 3 illustrates an exemplary PPDU 300 that may be used for communication between an AP 102 and one or more STAs 104. As described above, each PPDU 300 includes a PHY preamble 302 and a PSDU 304. Each PSDU 304 may represent (or "carry") one or more MAC Protocol Data Units (MPDUs) 316. For example, each PSDU 304 may carry an aggregate MPDU (A-MPDU) 306 that includes an aggregation of multiple A-MPDU subframes 308. Each A-MPDU frame 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 also include a frame check sequence (FCS) field 318 for error detection (e.g., the FCS field may include a cyclic redundancy check (CRC)) and padding bits 320. The MPDU 316 may carry one or more MAC service data units (MSDUs) 316. 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.

[0033] Referring again to the MPDU frame 310, the MAC delimiter 312 may serve as a marker of the start of the associated MPDU 316 and 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 acknowledgement (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 a frame type, for example, a data frame, a control frame, or a management frame.

[0034] 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, such as those defined by the IEEE 802.11-2016 specification or amendments thereto, including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be.

[0035] The wireless communication device 400 may be or include a chip, a system on a chip (SoC), a chipset, a package or device that includes one or more modems 402, e.g., 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 processing elements 406 (collectively "processors 406") and one or more memory blocks or elements 408 (collectively "memory 408").

[0036] The modem 402 may include, for example, an intelligent hardware block or device, such as an application specific integrated circuit (ASIC), among other possibilities. 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 a digital signal processing (DSP) circuit, an automatic gain control (AGC), a coder, a decoder, a multiplexer, and a demultiplexer. For example, during 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 modulated by a modulation constellation of 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 being provided 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 being provided to the IFFT block.

[0037] During 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 applying a digital gain to finally 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, for example, to calculate a log-likelihood ratio (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. The demultiplexed bits may then be descrambled and provided to a MAC layer (processor 406) for processing, evaluation, or interpretation.

[0038] 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.

[0039] The processor 406 may include intelligent hardware blocks or devices, such as, for example, a processing core, a processing block, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD) such as a field programmable gate array (FPGA), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor 406 processes information received through the radio 404 and the modem 402, and processes information to be output through the modem 402 and the radio 404 for transmission over a wireless medium. For example, the processor 406 may implement a control plane and a MAC layer 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 the various operations described above.

[0040] The memory 404 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 404 may also store non-transitory processor or computer executable software (SW) code, including 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.

[0041] 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 with the wireless communication device 510 for transmitting and receiving wireless communications. In some implementations, the AP 502 additionally includes an application processor 530 coupled with the wireless communication device 510, and a memory 540 coupled with 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 encloses 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.

[0042] 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, and the display 565 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 of the components via at least one bus. The STA 504 further includes a housing that encloses the wireless communication device 515, the application processor 535, the memory 545, and at least a portion of the antenna 525, the UI 555, and the display 565.

[0043] As described above, existing versions of the IEEE 802.11 standard define trigger frame formats that may be used to request one or more STAs to transmit a TB PPDU. The trigger frame allocates resources to one or more STAs for the transmission of the TB PPDU and indicates how the TB PPDU should be configured for transmission. For example, the trigger frame may indicate the RUs that are allocated for transmission in the TB PDDU. The RUs represent a set of tones or subcarriers across the wireless channel over which the TB PPDU should be transmitted. However, the TB PPDU cannot be transmitted according to existing versions of the IEEE 802.11 standard if any portion of the wireless channel is busy or otherwise unavailable. As new WLAN communication protocols enable enhanced WLAN communication capabilities (such as increased bandwidth and support for larger RUs and MRUs), new trigger frame and PPDU formats are needed to provide greater flexibility in medium utilization.

[0044] Various aspects relate generally to trigger-based communications supporting new wireless communication protocols, and more particularly to trigger frame and PPDU designs supporting RU downsizing. As used herein, the term "RU downsizing" refers to the transmission of a TB PPDU across RUs or MRUs that are smaller than the RUs or MRUs initially allocated in the TB PPDU. For example, an AP may transmit a trigger frame requesting a STA for a TB PPDU. In some aspects, the trigger frame may carry RU allocation information indicating the allocated RUs or MRUs (associated with the wireless medium) and downsizing information indicating whether downsizing of the RUs or MRUs is permitted. If interference is detected in a portion of the wireless medium (e.g., due to the medium being busy) and downsizing is permitted, the STA may transmit a TB PPDU on a tone (or "subcarrier") that spans the downsized RU or MRU. The downsized RU or MRU includes a subset of the tones in the RU or MRU allocated by the trigger frame. In some aspects, the downsized RU or MRU may be required to include one or more guaranteed tones. The guaranteed tones span a portion of the wireless medium where the AP expects to receive signaling for the TB PPDU, such as, for example, the PHY preamble. Thus, in some aspects, the STA may provide signaling for the downsized RU or MRU in the PHY preamble of the TB PPDU.

[0045] Particular implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages: RU downsizing provides greater flexibility in medium utilization for trigger-based communications. By allowing STAs to transmit TB PPDUs on a subset of tones allocated by trigger frames, aspects of the present disclosure may support increased network throughput achievable in accordance with the IEEE 802.11be amendment and future generations of the IEEE 802.11 standard. For example, if only a portion of the wireless medium is busy or unavailable, the STA may transmit TB PPDUs on tones spanning downsized RUs or MRUs that avoid the busy portion. As a result, the TB PPDUs may adapt to the conditions of the wireless medium. By requiring that the downsized RUs or MRUs include one or more guaranteed tones, aspects of the present disclosure may ensure that the AP can detect the TB PPDU and recover the information carried therein. For example, the PHY preamble of the TB PPDU may be decoded in its entirety from the guaranteed tones. Thus, by signaling the downsized RU or MRU in the PHY preamble, aspects of the present disclosure may ensure that the AP can identify the downsized RU or MRU in the TB PPDU by observing only the guaranteed tones.

[0046] FIG. 6 illustrates an exemplary trigger frame 600 that can be used for communication between an AP and some STAs according to some implementations. The trigger frame 600 can be used to request a TB PPDU from one or more STAs. For example, referring to FIG. 1, the AP 102 can transmit the trigger frame 600 to one or more of the STAs 104 to request a TB PPDU from the STAs. The trigger frame 600 can allocate RUs or MRUs for transmission in the TB PPDU. In some implementations, the trigger frame 600 can enable RU downsizing of one or more of the RUs or MRUs in the TB PPDU.

[0047] The trigger frame 600 includes a MAC header 610, a common information field 620, a user information list 630, zero or more padding bits 640, and an FCS 650. The MAC header 610 includes a frame control field, a duration field, a receiver address (RA) field, and a transmitter address (TA) field. The common information field 620 and the user information list 630 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 600. In some aspects, the user information list 630 may include one or more user information fields 632, each carrying per-user information for a respective user. In contrast, the common information field 620 may carry information that is common to all recipients of the trigger frame 600 (such as any users identified in the user information list 630).

[0048] In some implementations, each user information field 632 may carry RU allocation information 634 and RU downsizing information 636. The RU allocation information 634 indicates the RUs or MRUs allocated for transmission in the TB PPDU, and the RU downsizing information 636 indicates whether RU downsizing is allowed for the respective RU or MRU. In other words, the RU downsizing information 636 may indicate whether the TB PPDU may be transmitted on one or more tones across a downsized RU or MRU smaller than the RU or MRU indicated by the RU allocation information 634. Because the trigger frame 600 may include multiple user information fields 632 (to request TB PPDUs from multiple users), the RU downsizing information 636 may only apply to the RU allocation information 634 in the same user information field 632. In some aspects, the RU downsizing information 636 may be indicated by the value of a downsizing bit in the user information field 632. In some aspects, the RU allocation information 634 and the RU downsizing information 636 may be jointly indicated by the value of the RU allocation subfield of the user information field.

[0049] Aspects of the present disclosure recognize that the trigger frame 600 may include some reserved bits. The reserved bits represent unused bits that are reserved for future implementations of the IEEE 802.11 standard. In some aspects, one or more reserved bits in an earlier version or release of the IEEE 802.11 standard may be reused (to carry information) in a later version or release. For example, some reserved bits in the trigger frame 600 may be reused in a later version or release of the IEEE 802.11 standard to expand the range of values ​​that may be represented by an existing field in the earlier version or release. Some other reserved bits in the trigger frame 600 may be reused in a later version or release of the IEEE 802.11 standard to carry information that is not related to any information carried in the earlier version or release (or that remains unused in the later version or release). In some implementations, one or more of the reserved bits in the trigger frame 600 may be reused to carry RU allocation information 634.

[0050] FIG. 7 illustrates an example user information field 700 of a trigger frame formatted according to an existing trigger frame format. More specifically, the user information field 700 conforms to an Extremely High Throughput (EHT) variant user information field format defined by an initial release of the IEEE 802.11be amendment of the IEEE 802.11 standard. For example, with reference to FIG. 6, the user information field 700 may be an example of a user information field 632. Each user information field in the user information list is identified by a respective association identifier (AID) value in the AID12 subfield (bit positions B0-B11). In some aspects, the AID value may uniquely identify a particular STA (or user) in a BSS. As shown in FIG. 7, the user information field 700 includes a reserved bit (bit position B25). In some implementations, the reserved bit may be reused to carry RU downsizing information 636. For example, the reserved bit may be replaced by a downsizing bit (or subfield) in a future release or version of the IEEE 802.11 standard. Thus, a first value of the downsizing bit (e.g., "1") may indicate that RU downsizing is allowed, and a second value of the downsizing bit (e.g., "0") may indicate that RU downsizing is not allowed.

[0051] The user information field 700 also includes an RU allocation subfield (at bit positions B12-B19) and a PS160 subfield (at bit position B39). The combined values ​​of the RU allocation subfield and the PS160 subfield are mapped to an entry in the RU allocation table. The RU allocation table is a look-up table (LUT) that stores a number of entries that represent respective RU or MRU allocations. Specifically, each entry in the RU allocation table may indicate a bandwidth, a RU / MRU size, and a RU / MRU index. In some implementations, each entry in the RU allocation table may be configured to convey the RU allocation information 634 in addition to the RU downsizing information 636. For example, aspects of the present disclosure recognize that the RU allocation table associated with existing versions of the IEEE 802.11 standard includes a number of reserved entries (referred to herein as "downsizing entries") that may be reused to indicate RU / MRU allocations for which downsizing is permitted. Table 1 shows an exemplary RU allocation table suitable for conveying RU downsizing information 636 (for simplicity, only two entries are shown in Table 1).

[0052] [Table 1] As shown in Table 1, both entries in the RU allocation table identify the same MRU. However, the first entry in Table 1 (bits B7-B1 have a value equal to 104) represents an existing entry in the RU allocation table, and the second entry in Table 1 (bits B7-B1 have a value equal to 107) represents a downsized entry in the RU allocation table. In other words, the first entry can be found in the RU allocation table defined by an existing version of the IEEE 802.11 standard. In contrast, the second entry is reserved in the existing RU allocation table. When the value of the RU allocation subfield (and PS160 subfield) maps to a RU or MRU associated with an existing entry in the RU allocation table (such as the first entry in Table 1), RU downsizing is not allowed for that RU or MRU. On the other hand, when the value of the RU Allocation subfield (and PS160 subfield) maps to an RU or MRU associated with a downsize entry in the RU allocation table (such as the second entry in Table 1), RU downsizing is allowed for that RU or MRU.

[0053] FIG. 8 illustrates a frequency diagram 800 showing an example resource allocation of a wireless channel according to some implementations. More specifically, FIG. 8 illustrates a set of tones 802 that may be allocated in a TB PPDU and various tone configurations 812-824 that may be used for RU downsizing. For example, an AP may transmit a trigger frame (such as the trigger frame 600 of FIG. 6) requesting a TB PPDU to be transmitted by a STA on a set of allocated tones 802. In the example of FIG. 8, the allocated tones 802 represent 996-tone RUs across an 80 MHz wireless channel. In some implementations, the trigger frame may carry RU downsizing information indicating that downsizing is permitted for the allocated tones 802. For example, in some cases, a STA may detect interference in a portion of an 80 MHz channel due to the medium being busy (e.g., being used by another STA). In such cases, the STA may transmit a TB PPDU using one of the downsized tone configurations 812-824 that avoids the busy portion of the channel.

[0054] Each of the downsized tone configurations 812-816 spans three 20 MHz subchannels of the 80 MHz wireless channel. For example, downsized tone configuration 812 represents a 484+242 tone MRU across the second, third, and fourth 20 MHz subchannels, downsized tone configuration 814 represents a 484+242 tone MRU across the first, third, and fourth 20 MHz subchannels, downsized tone configuration 816 represents a 484+242 tone MRU across the first, second, and fourth 20 MHz subchannels, and downsized tone configuration 818 represents a 484+242 tone MRU across the first, second, and third 20 MHz subchannels. Each of the downsized tone configurations 822 and 824 spans a respective 40 MHz subchannel of the 80 MHz channel. For example, downsized tone configuration 822 represents 484 tone RUs across a first 40 MHz subchannel, and downsized tone configuration 824 represents 484 tone RUs across a second 40 MHz subchannel.

[0055] In some implementations, the downsized tone configurations 812-824 provide greater flexibility in medium utilization. For example, if a STA detects interference in one or more tones in the first 20 MHz of an 80 MHz channel, the STA may transmit a TB PPDU using the downsized tone configuration 812 or 824. Similarly, if a STA detects interference in one or more tones in the second 20 MHz subchannel of an 80 MHz channel, the STA may transmit a TB PPDU using the downsized tone configuration 814 or 824. Furthermore, if a STA detects interference in one or more tones in the third 20 MHz subchannel of an 80 MHz channel, the STA may transmit a TB PPDU using the downsized tone configuration 816 or 822. Furthermore, if a STA detects interference in one or more tones in the fourth 20 MHz subchannel of an 80 MHz channel, the STA may transmit a TB PPDU using the downsized tone configuration 818 or 822.

[0056] Aspects of the present disclosure recognize that it is difficult for the AP to recover the TB PPDU without knowing the tones on which the TB PPDU is transmitted. Thus, when a STA performs RU downsizing, the AP needs to know which of the downsized tone configurations 812-824 is used to transmit the TB PPDU. In some implementations, the downsized tone configuration may be required to include a subset of "guaranteed" tones of the allocated tones 802. The guaranteed tones may span subchannels on which the AP expects (or is guaranteed) to receive signaling for the downsized tone configuration. The signaling refers to a control field or information that may be used by a wireless communication device to interpret another field or portion of the PPDU. Aspects of the present disclosure recognize that the PHY preamble of the TB PPDU carries signaling for the TB PPDU and is replicated on each 20 MHz subchannel of the wireless channel associated with the TB PPDU. Thus, in some aspects, the guaranteed tones may span at least 20 MHz subchannels of the wireless channel associated with the allocated tones 802.

[0057] FIG. 9 illustrates a frequency diagram 900 showing an example resource allocation of a wireless channel including a guaranteed subchannel according to some implementations. More specifically, FIG. 9 illustrates a set of tones 902 that may be allocated in a TB PPDU and various tone configurations 912-918 that may be used for RU downsizing. For example, an AP may transmit a trigger frame (such as the trigger frame 600 of FIG. 6) requesting a TB PPDU to be transmitted by a STA on a set of allocated tones 902. In the example of FIG. 9, the allocated tones 902 represent 996-tone RUs across an 80 MHz wireless channel. In some implementations, the trigger frame may carry RU downsizing information indicating that downsizing is permitted for the allocated tones 902. Thus, if a STA detects interference in a portion of the 80 MHz channel, the STA may transmit a TB PPDU using one of the downsized tone configurations 912-918 that avoids the busy portion of the channel.

[0058] In some implementations, the first 20 MHz subchannel of the 80 MHz channel is associated with a set of guaranteed tones 920. Thus, each of the downsized tone configurations 912-918 is required to include at least the first 20 MHz subchannel. For example, downsized tone configuration 912 represents a 484+242 tone MRU across the first, third, and fourth 20 MHz subchannels, downsized tone configuration 914 represents a 484+242 tone MRU across the first, second, and fourth 20 MHz subchannels, downsized tone configuration 916 represents a 484+242 tone MRU across the first, second, and third 20 MHz subchannels, and downsized tone configuration 918 represents a 484 tone RU across the first 40 MHz subchannel. For example, referring to FIG. 8, the first 20 MHz subchannel is punctured in each of the downsized tone configurations 812 and 824. Thus, the downsized tone configurations 812 and 824 are not compatible with the guaranteed tones 920 and cannot be used to downsize the allocated tones 902 .

[0059] In the example of FIG. 9, the guaranteed tones 920 are shown to include the first 20 MHz subchannel of the 80 MHz channel. However, in some other implementations, the guaranteed tones may include any of the second, third, or fourth 20 MHz subchannels of the 80 MHz channel. Still further, in some implementations, the guaranteed tones may span subchannels greater than 20 MHz (e.g., 40 MHz subchannels) for wireless channels associated with larger RUs or MRUs (e.g., 2x996 tone RUs). In some implementations, the guaranteed tones 920 may be static or may be known to the STAs without any additional signaling from the AP. For example, in some aspects, the location of the guaranteed tones 920 may coincide with the location of the primary 20 MHz subchannel in a given wireless channel. In some other implementations, the guaranteed tones 920 may be dynamically allocated by the AP. For example, the AP may signal the location of the guaranteed tones 920 to the STAs. Such signaling is referred to herein as "RU guaranteed information."

[0060] In some implementations, the RU guarantee information may include a bitmap. Specifically, each bit of the bitmap may represent a respective subchannel of a given wireless channel. In some aspects, the bitmap may include 16 bits representing a 320 MHz channel. Thus, each bit of the bitmap may be associated with a respective 20 MHz subchannel of the 320 MHz channel. For example, any bit of the bitmap having a value equal to "1" may indicate that the guaranteed tone includes a 20 MHz subchannel associated with that bit. In some other aspects, the bitmap may include 8 bits representing a 320 MHz channel. Thus, each bit of the bitmap may be associated with a respective 40 MHz subchannel of the 320 MHz channel. For example, any bit of the bitmap having a value equal to "1" may indicate that the guaranteed tone includes a 40 MHz subchannel associated with that bit. Aspects of the present disclosure recognize that while bitmaps provide a high degree of flexibility in the allocation of guaranteed tones, they may also require a significant amount of signaling overhead.

[0061] In some other implementations, the RU guarantee information may signal the location of each of the guaranteed tones within each subchannel of a given wireless channel. In some aspects, the signaling may include four pairs of bits representing a 320 MHz channel, with each pair of bits associated with a respective 80 MHz subchannel. The value of each pair of bits may indicate which 20 MHz subchannel of the 80 MHz channel is associated with the guaranteed tone. For example, a pair of bits having a value of "00", "01", "10", or "11" may indicate that the guaranteed tone includes the first, second, third, or fourth 20 MHz subchannel of the 80 MHz channel, respectively. In some other aspects, the signaling may include two pairs of bits representing a 320 MHz channel, with each pair of bits associated with a respective 160 MHz subchannel. The value of each pair of bits may indicate which 40 MHz subchannel of the 160 MHz channel is associated with the guaranteed tone. For example, bit pairs having values ​​of "00", "01", "10", or "11" may indicate that the guaranteed tones include the first, second, third, or fourth 40 MHz subchannels of a 160 MHz channel, respectively. Aspects of the present disclosure recognize that requiring that there be a set of guaranteed tones in each subchannel of a wireless channel reduces signaling overhead, but also limits the flexibility in which the guaranteed tones can be allocated.

[0062] In some other implementations, the RU guarantee information may signal up to one set of guaranteed tones in each subchannel of a given wireless channel. Such signaling may require that at least five different values ​​be represented for each subchannel. For example, at least one of the values ​​may be used to indicate that the given subchannel does not include guaranteed tones, and the four remaining values ​​may be used to indicate the location of the guaranteed tones within the subchannel. In some aspects, each five-value set may be associated with a respective 80 MHz subchannel of a 320 MHz channel. For example, an integer value of 0 may indicate that the 80 MHz subchannel does not include any guaranteed tones, and integer values ​​of 1, 2, 3, and 4 may indicate that the guaranteed tones include the first, second, third, or fourth 20 MHz subchannel of the 80 MHz channel, respectively. In some implementations, three bits may be allocated to each 80 MHz channel for signaling binary representations of the values ​​0, 1, 2, 3, and 4 (such as "000", "001", "010", "011", and "100", respectively). However, aspects of the present disclosure recognize that such signaling requires significant overhead and results in several unused values ​​or bit combinations.

[0063] In some other implementations, the value associated with the first 80 MHz channel may be combined with the value associated with the second 80 MHz channel and mapped to a respective entry in a look-up table (LUT). In such implementations, the signaling may include 5 bits per 160 MHz bandwidth, with each 5-bit value mapping to one of 25 entries in the LUT. Table 2 shows an exemplary LUT suitable for signaling the location of up to one guaranteed tone in each 80 MHz subchannel of a 160 MHz channel.

[0064] [Table 2] As shown in Table 2, each 5-bit entry of the LUT indicates the location of a guaranteed tone (or the absence of a guaranteed tone) in a first 80 MHz subchannel of a 160 MHz channel, as well as the location of a guaranteed tone (or the absence of a guaranteed tone) in a second 80 MHz subchannel of a 160 MHz channel. An additional 5-bit LUT may be required to indicate the location of the guaranteed tone in the second 160 MHz channel. Thus, only 10 bits are required to signal the location of the guaranteed tone in a 320 MHz channel. In some aspects, the signaling overhead may be further reduced by changing the granularity of the guaranteed tone (such as from 20 MHz to 40 MHz). For example, Table 3 shows a LUT suitable for signaling the location of up to one guaranteed tone in each 160 MHz subchannel of a 320 MHz channel.

[0065] [Table 3] As shown in Table 3, each 5-bit entry in the LUT indicates the location of a guaranteed tone (or the absence of a guaranteed tone) in the first 160 MHz subchannel of a 320 MHz channel, as well as the location of a guaranteed tone (or the absence of a guaranteed tone) in the second 160 MHz subchannel of a 320 MHz channel. In this example, only 5 bits are needed to signal the location of the guaranteed tone in the 320 MHz channel.

[0066] In some implementations, the RU assurance information may be carried in a MAC management frame transmitted by the AP to one or more STAs. For example, the RU assurance information may be carried in an information element (IE) of one or more beacon frames broadcast by the AP. In some aspects, the size of the IE may be large enough to accommodate any of the signaling implementations described above (including a 16-bit bitmap). However, because the beacon frames are broadcast periodically, such implementations may not allow the AP to dynamically change the location of the assured tone to adapt to changes or variations in channel conditions. In some other implementations, the RU assurance information may be carried in each trigger frame transmitted by the AP to one or more STAs. This allows the AP to dynamically allocate assured tones per PPDU to adapt to channel conditions at any given time.

[0067] FIG. 10 illustrates another exemplary trigger frame 1000 usable for communication between an AP and some STAs according to some implementations. In some implementations, the trigger frame 1000 may be an example of the trigger frame 600 of FIG. 6. For example, the trigger frame 1000 may be used to request a TB PPDU from one or more STAs. The trigger frame 1000 may allocate RUs or MRUs to each STA for transmission within the TB PPDU. In some implementations, the trigger frame 1000 may enable RU downsizing of one or more RUs or MRUs within the TB PPDU.

[0068] The trigger frame 1000 includes a MAC header 1010, a common information field 1020, a user information list 1030, zero or more padding bits 1040, and an FCS 1050. The MAC header 1010 includes a frame control field, a duration field, an RA field, and a TA field. The common information field 1020 and the user information list 1030 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 1000. The user information list 1030 may include one or more user information fields 1032, each carrying per-user information for a respective user. In some implementations, each user information field 1032 may carry RU allocation information 1034 and RU downsizing information 1036. As described with reference to FIG. 6, RU allocation information 1034 indicates the RUs or MRUs allocated for transmission in the TB PPDU, and RU downsizing information 1036 indicates whether RU downsizing is allowed for the respective RU or MRU.

[0069] The common information field 1020 may carry information that is common to all recipients of the trigger frame 1000 (such as any users identified in the user information list 1030). In some implementations, the common information field 1020 may carry RU guarantee information 1022 indicating one or more guaranteed tones to be included in the downsized RU or MRU. In some aspects, the RU guarantee information 1022 may include an 8-bit bitmap, with each bit of the bitmap representing a respective 40 MHz subchannel of the 320 MHz channel. In some other aspects, the RU guarantee information 1022 may signal the location of each of the guaranteed tones within each 80 MHz or 160 MHz subchannel of the 320 MHz channel. Still further, in some aspects, the RU guarantee information 1022 may signal up to one set of guaranteed tones within each 80 MHz or 160 MHz subchannel of the 320 MHz wireless channel. In some implementations, the RU assurance information 1022 may replace one or more reserved bits in the common information field of the trigger frame format defined by existing versions of the IEEE 802.11 standard.

[0070] FIG. 11 illustrates a common information field 1100 of a trigger frame formatted according to an existing trigger frame format. More specifically, the common information field 1100 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. 10, the common information field 1100 may be an example of a common field 1020. In the example of FIG. 11, the common information field 1100 may be included in a trigger frame configured to request an EHT TB PPDU. Thus, the common information field 1100 includes a total of eleven reserved bits (bit positions B22, B26, B53, B56-B62, and B63). In some implementations, up to ten of the reserved bits may be reused to carry RU assurance information 1022. Aspects of the present disclosure recognize that the number of reserved bits in the common information field 1100 can support any of the signaling implementations for the RU assurance information 1022 described above with reference to FIG. 9, except for the 16-bit bitmap.

[0071] FIG. 12 illustrates another exemplary trigger frame 1200 usable for communication between an AP and some STAs according to some implementations. In some implementations, the trigger frame 1200 may be an example of the trigger frame 600 of FIG. 6. For example, the trigger frame 1200 may be used to request a TB PPDU from one or more STAs. The trigger frame 1200 may allocate RUs or MRUs to each STA for transmission in the TB PPDU. In some implementations, the trigger frame 1200 may enable RU downsizing of one or more RUs or MRUs in the TB PPDU.

[0072] 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, an RA field, and a 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. The user information list 1030 may include one or more user information fields 1032, each carrying per-user information for a respective user. In some implementations, each user information field 1232 may carry RU allocation information 1234 and RU downsizing information 1036. As described with reference to FIG. 6, RU allocation information 1234 indicates the RUs or MRUs allocated for transmission in the TB PPDU, and RU downsizing information 1236 indicates whether RU downsizing is allowed for the respective RU or MRU.

[0073] In some implementations, the user information list 1230 may further include a special user information field 1238. As described with reference to FIG. 7, each of the user information fields 1232 is identified by a unique AID value assigned to a particular STA (or user) in the BSS. In contrast, the special user information field 1238 may be identified by an AID value that is not assigned to any STA in the BSS. In some implementations, the special user information field 1238 may carry RU guarantee information 1239 indicating one or more guaranteed tones to be included in the downsized RU or MRU. In some aspects, the RU guarantee information 1239 may include an 8-bit bitmap, with each bit of the bitmap representing a respective 40 MHz subchannel of the 320 MHz channel. In some other aspects, the RU guarantee information 1239 may signal the location of each of the guaranteed tones in each 80 MHz or 160 MHz subchannel of the 320 MHz channel. Still further, in some aspects, the RU assurance information 1239 may signal up to one set of guaranteed tones in each 80 MHz or 160 MHz subchannel of the 320 MHz wireless channel. In some implementations, the RU assurance information 1239 may replace one or more reserved bits in the common information field of the trigger frame format defined by existing versions of the IEEE 802.11 standard.

[0074] FIG. 13 illustrates a special user information field 1300 of a trigger frame formatted according to an existing trigger frame format. More specifically, the special user information field 1300 conforms to the special 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. 12, the special user information field 1300 may be an example of the special user information field 1238. In the example of FIG. 13, the special user information field 1300 may be included in a basic trigger frame. Thus, the special user information field 1300 includes a total of 11 reserved bits (in bit positions B37-B39 and B40-B47). In some implementations, up to 10 of the reserved bits may be reused to carry RU assurance information 1239. Aspects of the present disclosure recognize that the number of reserved bits in the special user information field 1300 can support any of the signaling implementations for the RU assurance information 1239 described above with reference to FIG. 9, except for the 16-bit bitmap.

[0075] In some other implementations, the special user information field 1238 of the trigger frame 1200 may be a new special user information field. As described above, the special user information field may be any user information field associated with an AID value that is not assigned to any user or STA in a given BSS. As shown in FIG. 7, some AID values ​​associated with the AID12 subfield are reserved in existing versions of the IEEE 802.11 standard (such as 2008-2044 and 2047-4094). Thus, in some implementations, the special user information field 1238 may be assigned one or more of the reserved values ​​associated with the AID12 subfield. In such implementations, any number of the remaining bits of the special user information field 1238 (after the AID12 subfield) may be reused to carry RU assurance information 1239. Aspects of the present disclosure recognize that the remaining bits of the special user information field 1238 may support any of the signaling implementations for RU assurance information 1239 described above with reference to FIG. 9, including a 16-bit bitmap.

[0076] As described above, the RU guarantee information indicates a set of guaranteed tones to be included in any downsized RU or MRU used to transmit the TB PPDU. The guaranteed tones ensure that the AP can recover the TB PPDU from the downsized RU or MRU in which it is transmitted. In some implementations, the PHY preamble of the TB PPDU may carry signaling information indicating the downsized RU or MRU (also referred to herein as "downsized signaling information"). Aspects of the present disclosure recognize that the PHY preamble of the TB PPDU is replicated on each occupied 20 MHz subchannel of the channel width. In some aspects, each set of guaranteed tones may span at least 20 MHz of the subchannel. Thus, the AP may observe the PHY preamble transmitted on the guaranteed tones to determine how to recover the remainder of the TB PPDU. For example, the AP may decode the downsized signaling information in the PHY preamble to determine the downsized RU or MRU associated with the TB PPDU.

[0077] 14 illustrates an exemplary TB PPDU 1400 usable for communication between a STA and a number of APs, according to some implementations. The TB PPDU 1400 includes a PHY preamble including a first portion 1402 and a second portion 1404. The TB PPDU 1400 may further include a PHY payload 1406 after the preamble, e.g., in the form of a PSDU carrying a DATA field 1426. In some implementations, the TB PPDU 1400 may be formatted as a non-legacy or an Extremely High Throughput (EHT) PPDU.

[0078] The first part 1402 of the PHY preamble includes an L-STF 1408, an L-LTF 1410, and an L-SIG 1412. The second part 1404 of the PHY preamble includes a repeating legacy signal field (RL-SIG) 1414, a universal signal field (U-SIG) 1416, a non-legacy short training field (EHT-STF) 1422, and several non-legacy long training fields (EHT-LTF) 1424. In the IEEE 802.11be amendment and future generations of the IEEE 802.11 standard, new fields may be used to carry signaling information. At least some of the new fields and signaling information may be included in the U-SIG 1416. For example, the U-SIG 1416 may include signaling regarding the type or format of additional signal fields that may follow the U-SIG 1416. In some implementations, the U-SIG 1416 may carry downsizing signaling information 1418. The downsized signaling information 1418 may indicate whether RU downsizing is performed in the TB PPDU 1400 and the downsized RU or MRU (if RU downsizing is performed) associated with the TB PPDU 1400.

[0079] In some implementations, the downsized signaling information 1418 may include values ​​that are mapped to entries in the LUT. More specifically, each entry in the LUT may indicate a respective downsized RU or MRU. For example, with reference to FIG. 9, a first entry in the LUT (having a value equal to 0) may indicate the 996 tone RU associated with the allocated tone 902, a second entry in the LUT (having a value equal to 1) may indicate the 484+242 tone RU associated with the downsized tone configuration 912, a third entry in the LUT (having a value equal to 2) may indicate the 484+242 tone RU associated with the downsized tone configuration 914, a fourth entry in the LUT (having a value equal to 3) may indicate the 484+242 tone RU associated with the downsized tone configuration 916, and a fifth entry in the LUT (having a value equal to 4) may indicate the 484+242 tone RU associated with the downsized tone configuration 918.

[0080] In some other implementations, the downsized signaling information 1418 may include a first bit (also referred to as a "downsizing bit") to indicate whether RU downsizing is performed and several bits (also referred to as "location bits") to indicate the location of the dropped RUs. As shown in FIG. 9, each of the downsized tone configurations 912-918 includes a hole or gap in the 80 MHz channel associated with the allocated tone 902. For example, the downsized tone configuration 912 includes a 20 MHz gap that coincides with a second 20 MHz subchannel of the 80 MHz channel. The width of each gap is equal to the size of the RU (or MRU). Thus, the gaps in each downsized tone configuration are referred to herein as "dropped RUs." In some examples, the size of the dropped RUs may vary. For example, the dropped RUs in each of the downsized tone configurations 912-916 are sized as 242-tone RUs, and the dropped RUs in the downsized tone configuration 918 are sized as 484-tone RUs. Thus, in some implementations, the downsized signaling information 1418 may include an additional bit or bits to indicate the resolution or size (also referred to as “resolution bits”) of the dropped RUs.

[0081] The location bits may indicate the location of the dropped RU in the frequency domain. For example, referring to FIG. 9, the location bits may indicate which of the 20 MHz (or 40 MHz) subchannels is associated with the dropped RU. In some aspects, the value of the location bits may indicate the location of the dropped RU in increasing order of frequency (excluding guaranteed tones), with the lowest value representing the lowest frequency subchannel. Table 4 shows an example bit configuration that may be used to indicate each of the resource allocations shown in FIG. 9.

[0082] [Table 4] FIG. 15 illustrates a PPDU U-SIG 1500 formatted according to an existing PPDU format. More specifically, U-SIG 1500 conforms to the EHT TB PPDU format defined by the initial release of the IEEE 802.11be amendment of the IEEE 802.11 standard. For example, referring to FIG. 14, U-SIG 1500 may be an example of U-SIG 1416. According to the EHT TB PPDU format, the reserved bits are further subdivided into valid bits and ignore bits. The valid bits are used to indicate whether a STA should continue to receive the PPDU, and the ignore bits may be ignored by the receiving STA. Aspects of the present disclosure recognize that the ignore bits may be repurposed to carry downsized signaling information 1418. As illustrated in FIG. 15, U-SIG 1500 includes a total of 11 ignore bits distributed across two U-SIG symbols (U-SIG-1 and U-SIG-2). More specifically, U-SIG 1500 includes six ignored bits in U-SIG-1 (in bit positions B20-B25) and five ignored bits in U-SIG-2 (in bit positions B11-B15). In some implementations, downsized signaling information 1418 may reuse up to eleven of the ignored bits in U-SIG 1500.

[0083] 16 shows a sequence diagram 1600 illustrating an example message exchange between an AP 1610 and a STA 1620 in a wireless network. In some implementations, the AP 1610 may be an example of the AP 102 or 502 of FIG. 1 and FIG. 5A, respectively, and the STA 1620 may be an example of either the STA 104 or 504 of FIG. 1 and FIG. 5B, respectively.

[0084] The AP 1610 allocates an RU or an MRU to the TB PPDU 1604 to be transmitted by the STA 1620. The RU or MRU represents the wireless channel 1630 on which the TB PPDU 1604 is transmitted. Thus, the AP 1610 may select an RU or an MRU based on the condition of the wireless channel 1630. The AP 1610 transmits a trigger frame 1602 to request the TB PPDU 1604 from the STA 1620. In some implementations, the trigger frame 1602 may be an example of any of the trigger frames 600, 1000, 1200, 1400 of FIG. 6, FIG. 10, FIG. 12, and FIG. 14, respectively. Thus, the trigger frame 1602 may carry RU allocation information indicating the allocated RU or MRU in addition to RU downsizing information indicating whether RU downsizing is allowed in the TB PPDU 1604.

[0085] The STA 1620 receives the trigger frame 1602 from the AP 1610 and listens to the wireless channel 1630. For example, the STA 1620 may perform a clear channel assessment (CCA) on the wireless channel 1630 to determine whether the channel is busy or available for transmission of the TB PPDU 1604. In the example of FIG. 16, the STA 1620 detects interference 1632 in a portion of the wireless channel 1630. For example, the interference 1632 may be caused by wireless communication between other devices in the vicinity of the STA 1620 (such as in an overlapping BSS). In other words, the interference 1632 may be due to the medium being busy. Thus, the STA 1620 may determine whether RU downsizing is permitted by the trigger frame 1602 based on detecting the interference 1632 in the wireless channel.

[0086] In some implementations, the STA 1620 may selectively transmit the TB PPDU 1604 based on the RU downsizing information in the received trigger frame 1602. For example, if the RU downsizing information indicates that RU downsizing is not allowed, the STA 1620 may not transmit the TB PPDU 1604. On the other hand, if the RU downsizing information indicates that RU downsizing is allowed, the STA 1620 may determine whether the interference 1632 matches a set of guaranteed tones to be included in any downsized RU or MRU. In some aspects, the STA 1620 may determine the location of the guaranteed tones based on the location of the primary 20 MHz subchannel in the wireless channel 1630. In some other aspects, the STA 1620 may receive RU guarantee information from the AP 1610 indicating the location of the guaranteed tones (as described with reference to Figures 9-13).

[0087] If the interference 1632 matches one or more of the guaranteed tones, the STA 1620 may not transmit the TB PPDU 1604. On the other hand, if the interference 1632 does not match any of the guaranteed tones, the STA 1620 may transmit the TB PPDU 1604 using a downsized RU or MRU that avoids the interference 1632. As described with reference to Figures 8 and 9, the downsized RU or MRU may include a subset of the tones associated with the RU or MRU allocated by the trigger frame 1602. In some implementations, the TB PPDU 1604 may include downsized signaling information indicating that RU downsizing is performed in the TB PPDU 1604, as well as the downsized RU or MRU associated with the TB PPDU 1604 (as described with reference to Figures 14 and 15).

[0088] 17 is a flowchart illustrating an example process 1700 for wireless communication to support RU downsizing, in accordance with some implementations. In some implementations, the process 1700 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.

[0089] In some implementations, process 1700 begins at block 1702 with receiving a trigger frame requesting a TB PPDU from a wireless communication device, the trigger frame carrying RU allocation information indicating a number of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRUs) associated with the wireless medium. In some aspects, the downsizing information may be indicated by a value of a downsizing bit in the user information field. In some other aspects, the RU allocation information and the downsizing information may be jointly indicated by a value of a RU allocation subfield of the user information field.

[0090] At block 1704, process 1700 proceeds to determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of the wireless medium where interference is present. At block 1706, process 1700 proceeds to selectively transmit a TB PPDU on a subset of the tones of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU. In some implementations, the TB PPDU may include a PHY preamble having a U-SIG carrying downsized signaling information indicating the subset of tones. In some aspects, the downsized signaling information may be mapped to one of a plurality of entries in a LUT, each entry indicating a respective RU or MRU. In some other aspects, the downsized signaling information may indicate the remaining tones of the plurality of tones not included in the subset, the remaining tones representing a third RU or a third MRU.

[0091] In some implementations, the process 1700 may include receiving RU guarantee information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU, and selecting a subset of tones to exclude one or more unavailable tones and include one or more guaranteed tones. In some aspects, the RU guarantee information may be carried in a common information field preceding a user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame. In some other aspects, the RU guarantee information may be carried in a special user information field of the trigger frame, the special user information field being identified by an AID value not assigned to any wireless communication device associated with the same BSS as the wireless communication device. Still further, in some aspects, the RU guarantee information may be received in a management frame prior to reception of the trigger frame.

[0092] In some implementations, the RU guarantee information may include a bitmap, with each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with one or more guaranteed tones. Still further, in some implementations, the RU guarantee information may be mapped to one of a number of entries in a LUT, with each entry in the LUT indicating a respective combination of one or more subchannels of the wireless channel associated with one or more guaranteed tones.

[0093] 18 is a flow chart illustrating an example process 1800 for wireless communication to support RU downsizing, in accordance with some implementations. In some implementations, the process 1800 may be performed by a wireless communication device operating as or within an AP, such as one of the APs 102 or 502 of FIG. 1 and FIG. 5A, respectively.

[0094] In some implementations, the process 1800 begins at block 1802 with transmitting a trigger frame requesting a TB PPDU, where the trigger frame carries RU allocation information indicating a number of tones allocated to the TB PPDU and includes a user information field carrying downsizing information indicating that downsizing of the number of tones is permitted, where the number of tones represents a first RU or a first MRU. In some aspects, the downsizing information may be indicated by a value of a downsizing bit in the user information field. In some other aspects, the RU allocation information and the downsizing information are jointly indicated by a value of the RU allocation subfield of the user information field.

[0095] At block 1804, process 1800 proceeds to receive a TB PPDU on a subset of tones of the plurality of tones responsive to the trigger frame, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU. In some implementations, the TB PPDU may include a PHY preamble having a U-SIG carrying downsized signaling information indicating the subset of tones. In some aspects, the downsized signaling information may be mapped to one of a plurality of entries in a LUT, each entry in the LUT indicating a respective RU or MRU. In some other aspects, the downsized signaling information may indicate the remaining tones of the plurality of tones not included in the subset, the remaining tones representing a third RU or a third MRU.

[0096] In some implementations, the process 1800 may include transmitting RU allocation information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU, where a subset of the tones includes at least one or more guaranteed tones. In some aspects, the RU guarantee information may be carried in a common information field preceding a user information field in the trigger frame, where the common information field carries information common to each user associated with the trigger frame. In some other aspects, the RU guarantee information may be carried in a special user information field of the trigger frame, where the special user information field is identified by an AID value that is not assigned to any wireless communication device associated with the wireless communication device. Still further, in some aspects, the RU guarantee information may be carried in a management frame transmitted prior to transmission of the trigger frame.

[0097] In some implementations, the RU guarantee information may include a bitmap, with each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with one or more guaranteed tones. In some other implementations, the RU guarantee information may include one or more pairs of bits, with each of the one or more pairs of bits indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with one or more guaranteed tones. Still further, in some implementations, the RU guarantee information may be mapped to one of a number of entries in a LUT, with each entry in the LUT indicating a respective combination of one or more subchannels of the wireless channel associated with one or more guaranteed tones.

[0098] FIG. 19 shows a block diagram of an example wireless communication device according to some implementations. In some implementations, the wireless communication device 1900 is configured to perform the process 1700 described above with reference to FIG. 17. The wireless communication device 1900 may be an example implementation of the wireless communication device 400 described above with reference to FIG. 4. For example, the wireless communication device 1900 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).

[0099] The wireless communication device 1900 includes a receiving component 1910, a communications manager 1920, and a transmitting component 1930. The communications manager 1920 further includes a busy medium determining component 1922 and a RU downsizing component 1924. One or more portions of the components 1922-1924 may be implemented at least in part in hardware or firmware. In some implementations, at least some of the components 1922 or 1924 are implemented at least in part as software stored in a memory (e.g., memory 408). For example, one or more portions of the components 1922 and 1924 may be implemented as non-transitory instructions (or "code") executable by a processor (e.g., processor 406) to perform the functions or operations of the respective components.

[0100] The receiving component 1910 is configured to receive an RX signal from one or more other wireless communication devices over a wireless channel. In some implementations, the RX signal may include a trigger frame requesting a TB PPDU, where the trigger frame carries RU allocation information indicating a number of tones allocated to the TB PPDU and includes a user information field carrying downsizing information indicating whether downsizing of the number of tones is permitted, where the number of tones represents a first RU or a first MRU. The communications manager 1920 is configured to control or manage communications with the one or more other wireless communication devices. In some implementations, the busy medium determination component 1922 may determine that one or more tones of the number of tones are unavailable, where the one or more unavailable tones are associated with a portion of the wireless medium where interference is present, and the RU downsizing component 1924 may selectively transmit the TB PPDU on a subset of the tones of the number of tones based on the downsizing information, where the subset of tones represents a second RU or a second MRU that is smaller than the first RU or the first MRU. The transmitting component 1930 is configured to transmit the TX signal over a wireless channel to one or more other wireless communication devices.

[0101] 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).

[0102] The wireless communication device 2000 includes a receiving component 2010, a communications manager 2020, and a transmitting component 2030. The communications manager 2020 may further include a downsized RU determination component 2022. Portions of the downsized RU determination component 2022 may be implemented at least partially in hardware or firmware. In some implementations, the downsized RU determination component 2022 is implemented at least partially as software stored in a memory (such as the memory 408). For example, portions of the downsized RU determination component 2022 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.

[0103] The receiving component 2010 is configured to receive an RX signal from one or more other wireless communication devices over a wireless channel. The transmitting component 2030 is configured to transmit a TX signal to one or more other wireless communication devices over a wireless channel. In some implementations, the TX signal may include a trigger frame requesting a TB PPDU, the trigger frame carrying RU allocation information indicating a number of tones allocated to the TB PPDU, and a user information field carrying downsizing information indicating downsizing of the number of tones is permitted, the number of tones representing a first RU or a first MRU. The communications manager 2020 is configured to control or manage communications with the one or more other wireless communication devices. In some implementations, the downsized RU determination component 2022 may receive a TB PPDU on a subset of tones of the number of tones responsive to the trigger frame, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU.

[0104] Example implementations are described in the following numbered clauses.

[0105] 1. A method for wireless communication by a wireless communication device, comprising: receiving a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) from a wireless communication device, the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRU) associated with the wireless medium; determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of a wireless medium where interference is present; selectively transmitting the TB PPDU on a subset of tones of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU; The method includes:

[0106] 2. The method of claim 1, wherein the downsizing information is indicated by a value of a downsizing bit in a user information field.

[0107] 3. The method of claim 1, wherein the RU allocation information and the downsizing information are collectively indicated by the value of the RU allocation subfield of the user information field.

[0108] 4. receiving RU guarantee information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU; selecting a subset of tones to exclude one or more unavailable tones and to include at least one or more guaranteed tones; Any of the methods described in clauses 1 to 3, further including:

[0109] 5. Any of the methods of clauses 1 to 4, wherein the RU assurance information is carried in a common information field preceding a user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame.

[0110] 6. The method of any of clauses 1 to 4, wherein the RU assurance information is carried in a special user information field of the trigger frame, and the special user information field is identified by an association identifier (AID) value that is not assigned to any wireless communications device associated with the same basic service set (BSS) as the wireless communications device.

[0111] 7. The step of receiving RU warranty information includes: receiving a management frame carrying RU guarantee information prior to receiving the trigger frame; any of the methods described in clauses 1 to 4, including

[0112] 8. The method of any of clauses 1 to 7, wherein the RU guarantee information includes a bitmap, each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones.

[0113] 9. The method of any of clauses 1 to 7, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with one or more guaranteed tones.

[0114] 10. The method of any of clauses 1 to 7, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with one or more guaranteed tones.

[0115] 11. The method of any of clauses 1 to 7, wherein the RU guarantee information is mapped to one of a plurality of entries in a look-up table (LUT), each entry in the LUT indicating a respective combination of one or more sub-channels of the wireless channel associated with one or more guaranteed tones.

[0116] 12. The method of any of clauses 1 to 11, wherein the TB PPDU includes a physical layer preamble having a universal signal field (U-SIG) carrying downsized signaling information indicating a subset of the tones.

[0117] 13. The method of any of clauses 1 to 12, wherein the downsized signaling information is mapped to one of a number of entries in the LUT, each entry in the LUT indicating a respective RU or MRU.

[0118] 14. Any of the methods of clauses 1 to 2, wherein the downsized signaling information indicates remaining tones of the plurality of tones not included in the subset, the remaining tones representing a third RU or a third MRU.

[0119] 15. A wireless communication device, comprising: At least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code being configured, when executed by the at least one processor in conjunction with the at least one modem, to perform any one or more of the methods of clauses 1 to 14. Wireless communication devices.

[0120] 16. A method for wireless communication performed by a wireless communication device, comprising: transmitting a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU), the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating that downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRU); receiving a TB PPDU on a subset of tones of a plurality of tones responsive to the trigger frame, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU; A method comprising:

[0121] 17. The method of claim 16, wherein the downsizing information is indicated by a value of a downsizing bit in a user information field.

[0122] 18. The method of claim 16, wherein the RU allocation information and the downsizing information are collectively indicated by the value of the RU allocation subfield of the user information field.

[0123] 19. Transmitting RU allocation information indicating one or more tones of a plurality of tones guaranteed to be associated with the TB PPDU, the subset of tones including at least one or more guaranteed tones. Any of the methods set forth in clauses 16 to 18, further including:

[0124] 20. The method of any of clauses 16 to 19, wherein the RU assurance information is carried in a common information field preceding a user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame.

[0125] 21. The method of any of clauses 16 to 19, wherein the RU assurance information is carried in a special user information field of the trigger frame, and the special user information field is identified by an association identifier (AID) value that is not assigned to any wireless communication device associated with the wireless communication device.

[0126] 22. The step of transmitting RU allocation information comprises: transmitting a management frame carrying RU guarantee information prior to transmitting the trigger frame. any of the methods set out in clauses 16 to 19, including

[0127] 23. The method of any of clauses 16 to 22, wherein the RU guarantee information includes a bitmap, each bit of the bitmap indicating whether a respective subchannel of the wireless channel is associated with one or more guaranteed tones.

[0128] 24. The method of any of clauses 16 to 23, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with one or more guaranteed tones.

[0129] 25. The method of any of clauses 16 to 23, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with one or more guaranteed tones.

[0130] 26. The method of any of clauses 16 to 23, wherein the RU guarantee information is mapped to one of a plurality of entries in a look-up table (LUT), each entry in the LUT indicating a respective combination of one or more sub-channels of the wireless channel associated with one or more guaranteed tones.

[0131] 27. The method of any of clauses 16 to 26, wherein the TB PPDU includes a physical layer preamble having a universal signal field (U-SIG) carrying downsized signaling information indicating a subset of the tones.

[0132] 28. The method of any of clauses 16 to 27, wherein the downsized signaling information is mapped to one of a number of entries in a LUT, each entry in the LUT indicating a respective RU or MRU.

[0133] 29. The method of any of clauses 16 to 27, wherein the downsized signaling information indicates remaining tones of the plurality of tones not included in the subset, the remaining tones representing a third RU or a third MRU.

[0134] 30. A wireless communication device, comprising: At least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor readable code, the processor readable code being configured, when executed by the at least one processor in conjunction with the at least one modem, to perform any one or more of the methods of clauses 16 to 29. Wireless communication devices.

[0135] As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to 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.

[0136] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described with respect to 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. Interoperability of hardware, firmware, and software has been described generally in terms of functionality and is illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the particular application and design constraints imposed on the overall system.

[0137] 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 should be accorded the widest scope consistent with the present disclosure, the principles and novel features disclosed herein.

[0138] 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 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.

[0139] 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. Additionally, the figures may generally illustrate one or more exemplary processes in the form of a flowchart 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. [Explanation of symbols]

[0140] 100 Wireless Communication Networks 102 Access Point (AP) 104 stations (STA) 106 Coverage Area 108 Communication Links 200 Protocol Data Units (PDUs) 202 PHY Preamble 204 PHY Payload 206 Legacy Short Training Field (L-STF) 208 Legacy Long Training Field (L-LTF) 210 Legacy Signal Field (L-SIG) 212 Non-Legacy Fields 214 Data field (DATA) 222 Data Rate Field 224 reserved bits 226 Length Field 228 parity bits 230 Tail Field 300 PPDU 302 PHY Preamble 304 PSDU 306 Aggregated MPDU (A-MPDU) 308 A-MPDU Subframe 310 MPDU Frame 312 MAC Delimiter 314 MAC Header 316 MAC Protocol Data Unit (MPDU) 318 Frame Check Sequence (FCS) field 320 padding bits 322 Aggregate MSDU (A-MSDU) 324 A-MSDU subframe 328 Subframe Header 330 MSDU 332 padding bits 400 Wireless Communication Devices 402 Modem 404 Wireless 406 Wireless communication devices 406 Processor 408 Memory 502 AP 504 STA 510 Wireless Communication Devices (WCD) 515 Wireless Communication Devices 520 Antenna 525 Antenna 530 Application Processor 535 Application Processor 540 Memory 545 Memory 550 External Network Interface 555 User Interface (UI) 565 Display 575 Sensor 600 trigger frames 610 MAC Header 620 Common Information Fields 630 User Information List 632 User Information Fields 634 RU Allocation Information 636 U Downsizing Information 640 padding bits 650 FCS 700 User Information Fields 802 Allocated Tones 812~824 Tone Composition 902 Tone 912~918 Tone Composition 1000 trigger frames 1010 MAC Header 1020 Common Information Field 1022 RU Warranty Information 1030 User Information List 1032 User Information Field 1034 RU allocation information 1036 RU Downsizing Information 1040 padding bits 1050 FCS 1100 Common Information Field 1200 trigger frames 1210 MAC Header 1220 Common Information Fields 1230 User Information List 1232 User Information Fields 1234 RU Allocation Information 1236 RU Downsizing Information 1238 Special User Information Fields 1239 RU Warranty Information 1240 padding bits 1250 FCS 1300 Special User Information Fields 1400TB PPDU 1402 First Part 1404 Second Part 1406 PHY Payload 1408 L-STF 1410 L-LTF 1412 L-SIG 1414 Repeated Legacy Signal Field (RL-SIG) 1416 Universal Signaling Field (U-SIG) 1418 Downsizing Signaling Information 1422 Non-Legacy Short Training Field (EHT-STF) 1424 Non-Legacy Long Training Field (EHT-LTF) 1426 DATA Field 1500 U-SIG 1602 Trigger Frame 1604TB PPDU 1610 AP 1620 STA 1630 Wireless Channel 1632 Interference 1700 Process 1800 Processes 1900 Wireless Communication Devices 1910 Receiving Component 1920 Communications Manager 1922 Busy Media Decision Component 1924 RU Downsizing Components 1930 Transmission Component 2000 Wireless Communication Devices 2010 Inbound Component 2020 Communications Manager 2022 Downsized RU Decision Component 2030 Transmission Component

Claims

1. 1. A method for wireless communication performed by a wireless communication device, comprising: receiving a trigger frame requesting a trigger-based (TB) Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) from the wireless communication device, the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRUs) associated with a wireless medium; receiving RU guarantee information indicating one or more tones of the plurality of tones that are guaranteed to be associated with the TB PPDU; determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of the wireless medium where interference is present; selecting a subset of tones to exclude one or more unavailable tones and to include at least the one or more guaranteed tones; selectively transmitting the TB PPDU on a subset of the tones of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU; The method includes:

2. The method of claim 1 , wherein the downsizing information is indicated by a value of a downsizing bit in the user information field.

3. The method of claim 1 , wherein the RU allocation information and the downsizing information are collectively indicated by a value of a RU allocation subfield of the user information field.

4. 2. The method of claim 1, wherein the RU guarantee information is carried in a common information field preceding the user information field in the trigger frame, the common information field carrying information common to each user associated with the trigger frame.

5. 2. The method of claim 1, wherein the RU assurance information is carried in a special user information field of the trigger frame, the special user information field being identified by an association identifier (AID) value that is not assigned to any wireless communication device associated with a same basic service set (BSS) as the wireless communication device.

6. The step of receiving the RU guarantee information comprises: receiving a management frame carrying the RU assurance information prior to the reception of the trigger frame; 2. The method of claim 1, comprising:

7. 2. The method of claim 1, wherein the RU guarantee information comprises a bitmap, each bit of the bitmap indicating whether a respective subchannel of a wireless channel is associated with the one or more guaranteed tones.

8. 2. The method of claim 1, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 20 MHz subchannels of a respective 80 MHz channel are associated with the one or more guaranteed tones.

9. 2. The method of claim 1, wherein the RU guarantee information includes one or more bit pairs, each of the one or more bit pairs indicating which 40 MHz subchannels of a respective 160 MHz channel are associated with the one or more guaranteed tones.

10. 2. The method of claim 1, wherein the RU guarantee information is mapped to one of a plurality of entries in a look-up table (LUT), each entry in the LUT indicating a respective combination of one or more subchannels of a wireless channel associated with the one or more guaranteed tones.

11. the TB PPDU includes a physical layer preamble having a universal signal field (U-SIG) carrying downsized signaling information indicating the subset of tones; the downsized signaling information is mapped to one of a number of entries in a LUT, each entry in the LUT indicating a respective RU or MRU; or 2. The method of claim 1, wherein the downsized signaling information indicates remaining tones of the plurality of tones that are not included in the subset, the remaining tones representing a third RU or a third MRU.

12. 1. A wireless communication device, comprising: At least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code, when executed by the at least one processor in conjunction with the at least one modem, receiving a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) from the wireless communication device, the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU and including a user information field carrying downsizing information indicating whether downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRU) associated with a wireless medium; receiving RU guarantee information indicating one or more tones of the plurality of tones that are guaranteed to be associated with the TB PPDU; determining that one or more tones of the plurality of tones are unavailable, the one or more unavailable tones being associated with a portion of the wireless medium where interference is present; selecting a subset of tones to exclude one or more unavailable tones and to include at least the one or more guaranteed tones; selectively transmitting the TB PPDU on a subset of the tones of the plurality of tones based on the downsizing information, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU; [0023] Wireless communication devices.

13. 1. A method for wireless communication performed by a wireless communication device, comprising: transmitting a trigger frame requesting a trigger-based (TB) Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU), the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU, the trigger frame including a user information field carrying downsizing information indicating that downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRU); transmitting RU allocation information indicating one or more tones of the plurality of tones that are guaranteed to be associated with the TB PPDU; receiving the TB PPDU responsive to the trigger frame on a subset of tones of the plurality of tones, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU, the subset of tones including at least the one or more guaranteed tones; A method comprising:

14. 1. A wireless communication device, comprising: At least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code, when executed by the at least one processor in conjunction with the at least one modem, transmitting a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU), the trigger frame carrying resource unit (RU) allocation information indicating a number of tones allocated to the TB PPDU, the trigger frame including a user information field carrying downsizing information indicating that downsizing of the number of tones is allowed, the number of tones representing a first RU or a first number of resource units (MRU); transmitting RU allocation information indicating one or more tones of the plurality of tones that are guaranteed to be associated with the TB PPDU; receiving the TB PPDU responsive to the trigger frame on a subset of tones of the plurality of tones, the subset of tones representing a second RU or a second MRU that is smaller than the first RU or the first MRU, the subset of tones including at least the one or more guaranteed tones; [0023] Wireless communication devices.

15. A computer program comprising instructions, The instructions, when executed in the at least one processor of a wireless communication device according to claim 12, cause the at least one processor to perform a method according to any one of claims 1 to 11, 15. A computer program product comprising instructions, when executed in the at least one processor of a wireless communication device of claim 14, that cause the at least one processor to perform the method of claim 13.

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