SYNCHRONIZATION FOR URGENT DATA TRANSMISSION IN WI-FI NETWORKS

The present application provides an apparatus for a non-AP STA, including: RF interface circuitry; and processor circuitry coupled with the RF interface circuitry and configured to: monitor a trigger frame from an AP or ongoing uplink transmission from one or more non-AP STAs in a BSS associated with the AP and the non-AP STA to detect a location of a resource unit pre-allocated for transmission of urgent data; encode the urgent data for transmission to the AP via the RF interface circuitry on the resource unit, when the non-AP STA needs to transmit the urgent data; and pause the ongoing uplink transmission on the resource unit while continuing transmission of a pilot signal on the resource unit, when the non-AP STA does not need to transmit the urgent data.

TECHNICAL FIELD

Embodiments described herein generally relate to wireless communication, and more specifically to synchronization for urgent data transmission in Wi-Fi networks.

BACKGROUND

There is a recent demand for ultra-low latency transmission of urgent data in Wi-Fi networks to enable emerging time sensitive wireless communications. Non-orthogonal multiple access (NOMA) has emerged as a potential technology that enables multiplexing multi-users/transmissions over a resource unit. The NOMA technique can be used to enable uplink transmission from non-Access Point Stations (non-AP STA) that have urgent data to transmit in Wi-Fi networks.

DETAILED DESCRIPTION

Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of the disclosure to others skilled in the art. However, it will be apparent to those skilled in the art that many alternate embodiments may be practiced using portions of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well-known features may have been omitted or simplified in order to avoid obscuring the illustrative embodiments.

FIG. 1is a network diagram of an example network environment in accordance with some example embodiments of the disclosure. As shown inFIG. 1, a wireless network100may include one or more user devices102and one or more access points (APs)104, which may communicate in accordance with IEEE 802.11 communication standards. The user devices102may be mobile devices that are non-stationary (e.g., not having fixed locations) or may be stationary devices.

In some embodiments, the user devices102and APs104may include one or more function modules similar to those in the functional diagram ofFIG. 7and/or the example machine/system ofFIG. 8.

The one or more user devices102and/or APs104may be operable by one or more users110. It should be noted that any addressable unit may be a station (STA). A STA may take on multiple distinct characteristics, each of which shape its function. For example, a single addressable unit might simultaneously be a portable STA, a quality-of-service (QoS) STA, a dependent STA, and a hidden STA. In addition, according to the IEEE 802.11 communication standards, a WLAN may include multiple basic service sets (BSSs). A network node in the BSS is a STA, and the STA includes access point-type stations (abbreviated as APs) and non-access point stations (abbreviated as non-AP STAs). Each BSS may include one AP and multiple non-AP STAs associated with the AP.

The one or more user devices102and/or APs104may operate as a personal basic service set (PBSS) control point/access point (PCP/AP). The user devices102(e.g.,1024,1026, or1028) and/or APs104may include any suitable processor-driven device including, but not limited to, a mobile device or a non-mobile, e.g., a static device. For example, the user devices102and/or APs104may include, a user equipment (UE), a station (STA), an access point (AP), a software enabled AP (SoftAP), a personal computer (PC), a wearable wireless device (e.g., bracelet, watch, glasses, ring, etc.), a desktop computer, a mobile computer, a laptop computer, an ultrabook™ computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, an internet of things (IoT) device, a sensor device, a personal digital assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device (e.g., combining cellular phone functionalities with PDA device functionalities), a consumer device, a vehicular device, a non-vehicular device, a mobile or portable device, a non-mobile or non-portable device, a mobile phone, a cellular telephone, a personal communications service (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable global positioning system (GPS) device, a digital video broadcasting (DVB) device, a relatively small computing device, a non-desktop computer, a “carry small live large” (CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC), a mobile interne device (MID), an “origami” device or computing device, a device that supports dynamically composable computing (DCC), a context-aware device, a video device, an audio device, an A/V device, a set-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digital video disc (DVD) player, a high definition (HD) DVD player, a DVD recorder, a HD DVD recorder, a personal video recorder (PVR), a broadcast HD receiver, a video source, an audio source, a video sink, an audio sink, a stereo tuner, a broadcast radio receiver, a flat panel display, a personal media player (PMP), a digital video camera (DVC), a digital audio player, a speaker, an audio receiver, an audio amplifier, a gaming device, a data source, a data sink, a digital still camera (DSC), a media player, a smartphone, a television, a music player, or the like. Other devices, including smart devices such as lamps, climate control, car components, household components, appliances, etc. may also be included in this list.

The user devices102and/or APs104may also include mesh stations in, for example, a mesh network, in accordance with one or more IEEE 802.11 standards and/or 3 GPP standards.

(HFC) medium, microwave terrestrial transceivers, radio frequency communication mediums, white space communication mediums, ultra-high frequency communication mediums, satellite communication mediums, or any combination thereof.

Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may include one or more communications antennas. The one or more communications antennas may be any suitable type of antennas corresponding to the communications protocols used by the user devices102(e.g., user devices1024,1026and1028) and APs104. Some non-limiting examples of suitable communications antennas include Wi-Fi antennas, Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards compatible antennas, directional antennas, non-directional antennas, dipole antennas, folded dipole antennas, patch antennas, multiple-input multiple-output (MIMO) antennas, omnidirectional antennas, quasi-omnidirectional antennas, or the like. The one or more communications antennas may be communicatively coupled to a radio component to transmit and/or receive signals, such as communications signals to and/or from the user devices102and/or APs104.

Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may be configured to perform directional transmission and/or directional reception in conjunction with wirelessly communicating in a wireless network. Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may be configured to perform such directional transmission and/or reception using a set of multiple antenna arrays (e.g., DMG antenna arrays or the like). Each of the multiple antenna arrays may be used for transmission and/or reception in a particular respective direction or range of directions. Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may be configured to perform any given directional transmission towards one or more defined transmit sectors. Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may be configured to perform any given directional reception from one or more defined receive sectors.

MIMO beamforming in a wireless network may be accomplished using radio frequency (RF) beamforming and/or digital beamforming. In some embodiments, in performing a given MIMO transmission, the user devices102and/or APs104may be configured to use all or a subset of its one or more communications antennas to perform MIMO beamforming.

Any of the user devices102(e.g., user devices1024,1026,1028) and APs104may include any suitable radio and/or transceiver for transmitting and/or receiving radio frequency (RF) signals in the bandwidth and/or channels corresponding to the communications protocols utilized by any of the user devices102and APs104to communicate with each other. The radio components may include hardware and/or software to modulate and/or demodulate communications signals according to pre-established transmission protocols. The radio components may further have hardware and/or software instructions to communicate via one or more Wi-Fi and/or Wi-Fi direct protocols, as standardized by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. It should be understood that this list of communication channels in accordance with certain 802.11 standards is only a partial list and that other 802.11 standards may be used (e.g., Next Generation Wi-Fi, or other standards). In some embodiments, non-Wi-Fi protocols may be used for communications between devices, such as Bluetooth, dedicated short-range communication (DSRC), Ultra-High Frequency (UHF) (e.g. IEEE 802.11af, IEEE 802.22), white band frequency (e.g., white spaces), or other packetized radio communications. The radio component may include any known receiver and baseband suitable for communicating via the communications protocols. The radio component may further include a low noise amplifier (LNA), additional signal amplifiers, an analog-to-digital (A/D) converter, one or more buffers, and digital baseband.

There is a recent demand for enabling ultra-low latency transmission of urgent data in Wi-Fi networks to enable emerging time sensitive wireless communications. In order to enable the transmission of urgent data, certain resource units can be pre-allocated and pre-negotiated through one or a combination of the following methods: (a) defining preemption gaps, (b) utilizing known silent intervals, (c) defining pre-specified OFDM blank symbols on top of ongoing uplink transmission and (d) utilizing and enhancing an existing method/framework in the 802.11 specification for transmission of the urgent data such as NDP Feedback Report Poll (NFRP) or UL OFDMA-based random access (UORA).

With the allocated resource units, the urgent data can be transmitted between a non-AP STA and an AP by use of NOMA technique. The pre-negotiation for the resource units for transmission of the urgent data enables the AP and the non-AP STAs to be prepared to enable NOMA-receive paths when needed in order to reduce complexity of the receiver architecture and to avoid detection errors associated with a fully blind detector. However, on the transmitter side, it would require the transmitter to align and synchronize its transmission with the ongoing Transmission Opportunity (TxOP), the frame length and the OFDM symbol boundary. In this disclosure, mechanisms to enable such time alignment and synchronization will be described.

FIG. 2Ais a schematic diagram illustrating an example synchronization mechanism for urgent data transmission in a Wi-Fi network according to some embodiments of the present disclosure.

In some embodiments, a Protocol Data Unit (PDU) generated from the urgent data may be transmitted from a Non-STA AP to an AP upon receiving a trigger frame from the AP. For example, the AP may know about potential needs of transmission from a plurality of non-AP STAs through pre-negotiation and trigger the plurality of non-AP STAs to perform NOMA transmission in a resource unit pre-allocated for urgent transmission. In this case, a location of the resource unit can be pre-negotiated and broadcast in a beacon given dynamically in the trigger frame.

As shown inFIG. 2A, the AP may broadcast the location of the resource unit pre-allocated for urgent transmission to the plurality of non-AP STAs in a BSS of the AP via the downlink trigger frame. It is noted that inFIG. 2AandFIG. 2B, the resource unit is represented by a box filled with slashes. Any non-AP STA having urgent data to be transmitted to the AP may monitor the trigger frame to detect the location of the resource unit for NOMA transmission. In addition, the non-AP STA having the urgent data may monitor the trigger frame to also detect an OFDMA symbol boundary and estimate a frequency offset of the non-AP STA relative to the AP. The non-AP STA may pre-correct or compensate for the frequency offset and adjust required transmission power, and then transmit the urgent data on the pre-allocated resource unit.

In some embodiments, alternatively or additionally, the location of the pre-allocated resource unit may be provided in a header of ongoing uplink transmission from one or more non-AP STAs in the BSS associated with the AP and the non-AP STA having the urgent data.

FIG. 2Bis a schematic diagram illustrating an example synchronization mechanism for urgent data transmission in a Wi-Fi network according to some embodiments of the present disclosure. As shown inFIG. 2B, the location of the resource unit pre-allocated for urgent transmission may be provided as a preamble for synchronization in the ongoing uplink transmission. In this case, the non-AP STA having the urgent data may monitor the ongoing uplink transmission to detect the location of the resource unit pre-allocated for urgent transmission and an OFDMA symbol boundary so as to estimate a frequency offset of the non-AP STA relative to the ongoing uplink transmission. The non-AP STA may pre-correct or compensate for the frequency offset and adjust required transmission power, and then transmit the urgent data on the pre-allocated resource unit.

According to embodiments of the present disclosure, during the pre-allocated resource unit, the non-AP STA with the urgent data may transmit the urgent data to the AP and the ongoing uplink transmission may be paused, however, the non-AP STAs having no urgent data may continue transmitting pilot signals on the pre-allocated resource unit to allow continuous pilot tracking by the AP. On the other hand, the non-AP STA with the urgent data may monitor the trigger frame or the ongoing uplink transmission to detect a location of a pilot subcarrier and null out the location of the pilot subcarrier so as to transmit the urgent data on the pre-allocated resource unit.

As described above, the resource units for NOMA transmission may be pre-allocated by defining pre-specified OFDM blank symbols on top of ongoing uplink transmission.FIG. 3Ashows an example contention-based NOMA transmission on top of ongoing OFDMA uplink transmission according to some embodiments of the present disclosure. In some embodiments, urgent data may transmitted by using the NOMA technique, a non-AP STA with the urgent data may be a member of a NOMA group, which includes a plurality of non-AP STAs and has a NOMA group identifier, and the resource unit pre-assigned for urgent transmission may be pre-allocated to the non-AP STA based on the NOMA group identifier. Thus the NOMA transmission on top of the ongoing OFDMA uplink transmission may be called contention-based NOMA transmission herein. The plurality of non-AP STAs may be pre-grouped into a NOMA group and addressed by their NOMA-group identifier, but it should be appreciated that not all non-AP STAs in a NOMA group shall perform NOMA transmission concurrently.

The synchronization mechanism proposed in the present disclosure will be further described below with reference to the example contention-based NOMA transmission shown inFIG. 3A.

As shown inFIG. 3A, in a triggered uplink transmission, certain OFDM symbols may be assigned to be “blank” to provide an opportunity for NOMA transmission. In some embodiments, a short slot of a couple of OFDM symbol durations may be dedicated and pre-assigned for transmission of urgent data. Such short slot can be utilized for transmission of only a NOMA signature predefined for identifying a non-AP STA with the urgent data, signaling the AP that the non-AP STA requests a future uplink trigger-based transmission opportunity to send the urgent data along with the signature. The signature can be multiplexed with a few bits of data to indicate the requested bandwidth (BW). This can be utilized for a low latency case where the non-AP STA does not need to immediately preempt an ongoing for example downlink transmission, but can wait till an end of the ongoing transmission, then without a need to perform Enhanced Distributed Channel Access (EDCA), the non-AP STA would perform its next transmission. InFIG. 3A, blank symbols for transmission of NOMA signatures are shown using a High Efficiency (HE) Trigger-Based (TB) Physical layer (PHY) PDU format, although this is not a restriction. Also, the blank symbols may occur more than once and with different time durations within a packet.

It is noted that inserting blank symbols may cause problems with pilot tracking of the ongoing transmission. Such problems can be addressed by the synchronization mechanism proposed in the present disclosure as described with reference toFIG. 2AandFIG. 2B. Specifically, the problems can be addressed by selectively blanking only data subcarriers while continuing the transmission of pilot subcarriers. The location of blank symbols can be pre-specified, e.g., given in the trigger frame from the AP or in the header of the ongoing uplink transmission from one or more non-AP STAs in the BSS of the AP. During the blank symbols, the ongoing uplink transmission stops, but the non-AP STAs with no urgent data (may also referred to as regular non-AP STAs) continue transmitting pilot subcarriers with the same power per subcarrier. In this way, the ongoing uplink transmission will be successfully received by the AP after the blank symbols because the pilot tracking continues.

Alternatively, the resource units for NOMA transmission may be pre-allocated by defining preemption gaps during the ongoing uplink transmission.FIG. 3Bshows an example contention-based NOMA transmission on top of ongoing OFDMA uplink transmission according to some embodiments of the present disclosure. As shown inFIG. 3B, the resource units for NOMA transmission may include a plurality of preemption gaps during the ongoing uplink transmission. Similar to the case of inserting blank symbols inFIG. 3A, defining the preemption gaps may also cause problems with pilot tracking of the ongoing transmission, and the problems can also be addressed by the synchronization mechanism proposed in the present disclosure. The details of the synchronization mechanism for the case inFIG. 3Bare similar to that for the case inFIG. 3Aand thus will not be repeated here. In addition, as shown inFIG. 3B, each preemption gap may be followed by a midamble which may also be used for the synchronization.

It should be noted that although the synchronization mechanism according to the present disclosure is described only with reference to the two example cases for contention-based NOMA transmission, the synchronization mechanism may be applied to other similar frameworks for supporting NOMA transmission of urgent data in Wi-Fi networks.

According to the synchronization mechanism proposed in the present disclosure, related behaviors at the non-AP STA with urgent data, the non-AP STA without urgent data and the AP may be as follows:

Behaviors at the non-AP STA with urgent data: monitoring the trigger frame from the AP or the ongoing uplink transmission to detect the location of the resource unit pre-allocated for urgent transmission, the OFDMA symbol boundary and other physical layer information such as the location of pilot subcarriers; estimating the frequency offset of the non-AP STA relative to the AP or the ongoing transmission and compensating the frequency offset; transmitting the urgent data on the pre-allocated resource unit.

Behaviors at the non-AP STA without urgent data: monitoring the trigger frame from the AP or the ongoing uplink transmission to detect the location of the resource unit pre-allocated for urgent transmission; pausing the ongoing uplink transmission on the pre-allocated resource unit while continuing transmission of a pilot signal on the pre-allocated resource unit.

Behaviors at the AP: tracking ongoing uplink transmission from one or more non-AP STAs in a BSS of the AP based on pilot signals transmitted by the one or more non-AP STAs, the pilot signals including a pilot signal transmitted on the resource unit by a non-AP STA having no urgent data to transmit; determining, based on a trigger frame from the AP or the ongoing uplink transmission, a location of a resource unit pre-allocated for a non-AP STA having urgent data; decoding the urgent data received from the non-AP STA on the resource unit.

FIG. 4Ais a flowchart illustrating example operations at a non-AP STA for urgent data transmission by use of a synchronization mechanism according to some embodiments of the present disclosure. It should be noted that the non-AP STA may include a non-AP STA with urgent data or a non-AP STA without urgent data, and the non-AP STA may or may not need to transmit urgent data according to actual situations. As shown inFIG. 4A, the operations at the non-AP STA may include operations410to430.

At operation410, the non-AP STA may monitor a trigger frame from an AP or ongoing uplink transmission from one or more non-AP STAs in a BSS associated with the AP and the non-AP STA to detect a location of a resource unit pre-allocated for transmission of urgent data.

At operation420, when the non-AP STA needs to transmit the urgent data, the non-AP STA may encode the urgent data for transmission to the AP via the RF interface circuitry on the resource unit.

At operation430, when the non-AP STA does not need to transmit the urgent data, the non-AP STA may pause the ongoing uplink transmission on the resource unit while continuing transmission of a pilot signal on the resource unit.

In some embodiments, when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the non-AP STA may monitor the trigger frame or the ongoing uplink transmission to detect an OFDMA symbol boundary and estimate a frequency offset of the non-AP STA relative to the AP or the ongoing uplink transmission, and compensate the frequency offset to synchronize with the AP or the ongoing uplink transmission.

In some embodiments, the resource unit may include a pre-allocated blank symbol during the ongoing uplink transmission.

In some embodiments, the resource unit may include a pre-allocated preemption gap during the ongoing uplink transmission, and the preemption gap may be followed by a midamble.

In some embodiments, when the non-AP STA needs to transmit the urgent data, the non-AP STA may encode the urgent data for transmission to the AP by use of NOMA technique. The non-AP STA may be a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit may be pre-allocated for the multiple non-AP STAs based on the NOMA group identifier. When the non-AP STA needs to transmit the urgent data, the non-AP STA may encode a NOMA signature pre-defined for identifying the non-AP STA for transmission to the AP on the resource unit.

In some embodiments, when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the non-AP STA may monitor the trigger frame or the ongoing uplink transmission to detect a location of a pilot subcarrier and null out the location of the pilot subcarrier.

FIG. 4Bis a flowchart illustrating example operations at an AP for urgent data transmission by use of a synchronization mechanism according to some embodiments of the present disclosure. As shown inFIG. 4B, the operations at the AP may include operations440to460.

At operation440, the AP may track ongoing uplink transmission from one or more non-AP STAs in a BSS of the AP based on pilot signals transmitted by the one or more non-AP STAs.

At operation450, the AP may determine, based on a trigger frame from the AP or the ongoing uplink transmission, a location of a resource unit pre-allocated for a non-AP STA having urgent data to be transmitted to the AP. The pilot signals may include a pilot signal transmitted on the resource unit by a regular non-AP STA having no urgent data to transmit.

At operation460, the AP may decode the urgent data received from the non-AP STA on the resource unit.

In some embodiments, the resource unit may include a pre-allocated blank symbol during the ongoing uplink transmission.

In some embodiments, the resource unit may include a pre-allocated preemption gap during the ongoing uplink transmission, and the preemption gap may be followed by a midamble.

In some embodiments, the urgent data may be transmitted by use of NOMA technique. The non-AP STA having urgent data to transmit may be a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit may be pre-allocated for the multiple non-AP STAs based on the NOMA group identifier. The AP may decode the urgent data based on a NOMA signature pre-defined for identifying the non-AP STA and received from the non-AP STA on the resource unit.

In some embodiments, blank symbols can be defined even during a downlink transmission to reduce the latency for urgent uplink packets. The AP may stop transmission during the blank symbols, and instead the AP receiver may search and decode uplink NOMA transmission. Right after the blank symbols, AP may transmit a midamble to enable re-synchronization and continue its regular transmission.

Alternatively, the non-AP STAs with urgent data can also smartly populate pilot subcarriers to enable phase tracking at the end of receiving the downlink transmission. The regular non-AP STAs without urgent data may monitor the presence of any NOMA transmission at the end of receiving the downlink transmission. Optionally, if the NOMA transmission does exist (energy detection can be sufficient), the regular non-AP STAs can assume the downlink transmission will be terminated at this point. In this case, the NOMA transmission can continue for the rest of Tx-OP duration. This alternative can be viewed as an opportunistic preemption, when and if needed, the original ongoing transmission can be aborted by the AP.

Accordingly, in some embodiments, the AP may allocate a blank symbol during downlink transmission, and pause the downlink transmission during the black symbol to detect and decode the urgent data received from the non-AP STA. The AP may encode a midamble after the blank symbol for transmission to the one or more non-AP STAs to enable re-synchronization.

According to embodiments of the present disclosure, at any given resource unit pre-allocated for urgent transmission, more than one non-AP STA may randomly transmit urgent data, and the AP can detect and decode the urgent data from several non-AP STAs. The interference with the ongoing transmission and among the non-AP STAs can be avoided or mitigated. The OFDM-boundary level synchronization can be performed, which in turn would enable utilization of pilot subcarriers for phase tracking during the resource units pre-allocated for urgent transmission. In addition, the maximum delay in NOMA transmission can be configured by the frequency and the number of resource units within a Tx-OP.

FIG. 5shows a functional diagram of an exemplary communication station500, in accordance with one or more example embodiments of the disclosure. In one embodiment,FIG. 5illustrates a functional block diagram of a communication station that may be suitable for use as the AP104(FIG. 1) or the user device102(FIG. 1) in accordance with some embodiments. The communication station500may also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) device.

The communication station500may include communications circuitry502and a transceiver510for transmitting and receiving signals to and from other communication stations using one or more antennas501. The communications circuitry502may include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication station500may also include processing circuitry506and memory508arranged to perform the operations described herein. In some embodiments, the communications circuitry502and the processing circuitry506may be configured to perform operations detailed in the above figures, diagrams, and flows.

In accordance with some embodiments, the communications circuitry502may be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitry502may be arranged to transmit and receive signals. The communications circuitry502may also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitry506of the communication station500may include one or more processors. In other embodiments, two or more antennas501may be coupled to the communications circuitry502arranged for transmitting and receiving signals. The memory508may store information for configuring the processing circuitry506to perform operations for configuring and transmitting message frames and performing the various operations described herein. The memory508may include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memory508may include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media.

The machine (e.g., computer system)600may include a hardware processor602(e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory604and a static memory606, some or all of which may communicate with each other via an interlink (e.g., bus)608. The machine600may further include a power management device632, a graphics display device610, an alphanumeric input device612(e.g., a keyboard), and a user interface (UI) navigation device614(e.g., a mouse). In an example, the graphics display device610, alphanumeric input device612, and UI navigation device614may be a touch screen display. The machine600may additionally include a storage device (i.e., drive unit)616, a signal generation device618(e.g., a speaker), a multi-link parameters and capability indication device619, a network interface device/transceiver620coupled to antenna(s)630, and one or more sensors628, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensor. The machine600may include an output controller634, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.)). The operations in accordance with one or more example embodiments of the disclosure may be carried out by a baseband processor. The baseband processor may be configured to generate corresponding baseband signals. The baseband processor may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with the hardware processor602for generation and processing of the baseband signals and for controlling operations of the main memory604, the storage device616, and/or the multi-link parameters and capability indication device619. The baseband processor may be provided on a single radio card, a single chip, or an integrated circuit (IC).

The multi-link parameters and capability indication device619may carry out or perform any of the operations and processes (e.g., methods300and400) described and shown above.

It is understood that the above are only a subset of what the multi-link parameters and capability indication device619may be configured to perform and that other functions included throughout this disclosure may also be performed by the multi-link parameters and capability indication device619.

FIG. 7is a block diagram of a radio architecture700A,700B in accordance with some embodiments that may be implemented in any one of APs104and/or the user devices102ofFIG. 1. Radio architecture700A,700B may include radio front-end module (FEM) circuitry704a-b, radio IC circuitry706a-band baseband processing circuitry708a-b. Radio architecture700A,700B as shown includes both WLAN functionality and Bluetooth (BT) functionality although embodiments are not so limited. In this disclosure, “WLAN” and “Wi-Fi” are used interchangeably.

FEM circuitry704a-bmay include a WLAN or Wi-Fi FEM circuitry704aand a Bluetooth (BT) FEM circuitry704b.The WLAN FEM circuitry704amay include a receive signal path comprising circuitry configured to operate on WLAN RF signals received from one or more antennas701, to amplify the received signals and to provide the amplified versions of the received signals to the WLAN radio IC circuitry706afor further processing. The BT FEM circuitry704bmay include a receive signal path which may include circuitry configured to operate on BT RF signals received from one or more antennas701, to amplify the received signals and to provide the amplified versions of the received signals to the BT radio IC circuitry706bfor further processing. FEM circuitry704amay also include a transmit signal path which may include circuitry configured to amplify WLAN signals provided by the radio IC circuitry706afor wireless transmission by one or more of the antennas701. In addition, FEM circuitry704bmay also include a transmit signal path which may include circuitry configured to amplify BT signals provided by the radio IC circuitry706bfor wireless transmission by the one or more antennas. In the embodiment ofFIG. 7, although FEM704aand FEM704bare shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of an FEM (not shown) that includes a transmit path and/or a receive path for both WLAN and BT signals, or the use of one or more FEM circuitries where at least some of the FEM circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

Baseband processing circuitry708a-bmay include a WLAN baseband processing circuitry708aand a BT baseband processing circuitry708b.The WLAN baseband processing circuitry708amay include a memory, such as, for example, a set of RAM arrays in a Fast Fourier Transform or Inverse Fast Fourier Transform block (not shown) of the WLAN baseband processing circuitry708a. Each of the WLAN baseband circuitry708aand the BT baseband circuitry708bmay further include one or more processors and control logic to process the signals received from the corresponding WLAN or BT receive signal path of the radio IC circuitry706a-b, and to also generate corresponding WLAN or BT baseband signals for the transmit signal path of the radio IC circuitry706a-b. Each of the baseband processing circuitries708aand708bmay further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with a device for generation and processing of the baseband signals and for controlling operations of the radio IC circuitry706a-b.

Referring still toFIG. 7, according to the shown embodiment, WLAN-BT coexistence circuitry713may include logic providing an interface between the WLAN baseband circuitry708aand the BT baseband circuitry708bto enable use cases requiring WLAN and BT coexistence. In addition, a switch703may be provided between the WLAN FEM circuitry704aand the BT FEM circuitry704bto allow switching between the WLAN and BT radios according to application needs. In addition, although the antennas701are depicted as being respectively connected to the WLAN FEM circuitry704aand the BT FEM circuitry704b, embodiments include within their scope the sharing of one or more antennas as between the WLAN and BT FEMs, or the provision of more than one antenna connected to each of FEM704aor704b.

In some embodiments, the front-end module circuitry704a-b, the radio IC circuitry706a-b, and baseband processing circuitry708a-bmay be provided on a single radio card, such as wireless radio card702. In some other embodiments, the one or more antennas701, the FEM circuitry704a-band the radio IC circuitry706a-bmay be provided on a single radio card. In some other embodiments, the radio IC circuitry706a-band the baseband processing circuitry708a-bmay be provided on a single chip or integrated circuit (IC), such as IC712.

In some embodiments, the radio architecture700A,700B may be configured for high-efficiency Wi-Fi (HEW) communications in accordance with the IEEE 802.11ax standard. In these embodiments, the radio architecture700A,700B may be configured to communicate in accordance with an OFDMA technique, although the scope of the embodiments is not limited in this respect.

In some embodiments, as further shown inFIG. 7, the BT baseband circuitry708bmay be compliant with a Bluetooth (BT) connectivity standard such as Bluetooth, Bluetooth 8.0 or Bluetooth 6.0, or any other iteration of the Bluetooth Standard.

In some embodiments, the radio architecture700A,700B may include other radio cards, such as a cellular radio card configured for cellular (e.g., 5GPP such as LTE, LTE-Advanced or 5G communications).

In some IEEE 802.11 embodiments, the radio architecture700A,700B may be configured for communication over various channel bandwidths including bandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz, and bandwidths of about 2 MHz, 4 MHz, 5 MHz, 5.5 MHz, 6 MHz, 8 MHz, 10 MHz, 20 MHz, 40 MHz, 80 MHz (with contiguous bandwidths) or 80+80 MHz (160 MHz) (with non-contiguous bandwidths). In some embodiments, a 720 MHz channel bandwidth may be used. The scope of the embodiments is not limited with respect to the above center frequencies however.

FIG. 8illustrates WLAN FEM circuitry704ain accordance with some embodiments. Although the example ofFIG. 8is described in conjunction with the WLAN FEM circuitry704a,the example ofFIG. 8may be described in conjunction with the example BT FEM circuitry704b(FIG. 7), although other circuitry configurations may also be suitable.

In some embodiments, the FEM circuitry704amay include a TX/RX switch802to switch between transmit mode and receive mode operation. The FEM circuitry704amay include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry704amay include a low-noise amplifier (LNA)806to amplify received RF signals803and provide the amplified received RF signals807as an output (e.g., to the radio IC circuitry706a-b(FIG. 7)). The transmit signal path of the circuitry704amay include a power amplifier (PA) to amplify input RF signals809(e.g., provided by the radio IC circuitry706a-b), and one or more filters812, such as band-pass filters (BPFs), low-pass filters (LPFs) or other types of filters, to generate RF signals815for subsequent transmission (e.g., by one or more of the antennas701(FIG. 7)) via an example duplexer814.

In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry704amay be configured to operate in either the 2.4 GHz frequency spectrum or the 5 GHz frequency spectrum. In these embodiments, the receive signal path of the FEM circuitry704amay include a receive signal path duplexer804to separate the signals from each spectrum as well as provide a separate LNA806for each spectrum as shown. In these embodiments, the transmit signal path of the FEM circuitry704amay also include a power amplifier810and a filter812, such as a BPF, an LPF or another type of filter for each frequency spectrum and a transmit signal path duplexer814to provide the signals of one of the different spectrums onto a single transmit path for subsequent transmission by the one or more of the antennas701(FIG. 7). In some embodiments, BT communications may utilize the 2.4 GHz signal paths and may utilize the same FEM circuitry704aas the one used for WLAN communications.

FIG. 9illustrates radio IC circuitry706ain accordance with some embodiments. The radio IC circuitry706ais one example of circuitry that may be suitable for use as the WLAN or BT radio IC circuitry706a/706b(FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example ofFIG. 9may be described in conjunction with the example BT radio IC circuitry706b.

In some embodiments, the radio IC circuitry706amay include a receive signal path and a transmit signal path. The receive signal path of the radio IC circuitry706amay include at least mixer circuitry902, such as, for example, down-conversion mixer circuitry, amplifier circuitry906and filter circuitry908. The transmit signal path of the radio IC circuitry706amay include at least filter circuitry912and mixer circuitry914, such as, for example, up-conversion mixer circuitry. Radio IC circuitry706amay also include synthesizer circuitry904for synthesizing a frequency905for use by the mixer circuitry902and the mixer circuitry914. The mixer circuitry902and/or914may each, according to some embodiments, be configured to provide direct conversion functionality. The latter type of circuitry presents a much simpler architecture as compared with standard super-heterodyne mixer circuitries, and any flicker noise brought about by the same may be alleviated for example through the use of OFDM modulation.FIG. 9illustrates only a simplified version of a radio IC circuitry, and may include, although not shown, embodiments where each of the depicted circuitries may include more than one component. For instance, mixer circuitry914may each include one or more mixers, and filter circuitries908and/or912may each include one or more filters, such as one or more BPFs and/or LPFs according to application needs. For example, when mixer circuitries are of the direct-conversion type, they may each include two or more mixers.

In some embodiments, mixer circuitry902may be configured to down-convert RF signals807received from the FEM circuitry704a-b(FIG. 7) based on the synthesized frequency905provided by synthesizer circuitry904. The amplifier circuitry906may be configured to amplify the down-converted signals and the filter circuitry908may include an LPF configured to remove unwanted signals from the down-converted signals to generate output baseband signals907. Output baseband signals907may be provided to the baseband processing circuitry708a-b(FIG. 7) for further processing. In some embodiments, the output baseband signals907may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry902may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry914may be configured to up-convert input baseband signals911based on the synthesized frequency905provided by the synthesizer circuitry904to generate RF output signals809for the FEM circuitry704a-b. The baseband signals911may be provided by the baseband processing circuitry708a-band may be filtered by filter circuitry912. The filter circuitry912may include an LPF or a BPF, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry902and the mixer circuitry914may each include two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion respectively with the help of synthesizer904. In some embodiments, the mixer circuitry902and the mixer circuitry914may each include two or more mixers each configured for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry902and the mixer circuitry914may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuitry902and the mixer circuitry914may be configured for super-heterodyne operation, although this is not a requirement.

Mixer circuitry902may comprise, according to one embodiment: quadrature passive mixers (e.g., for the in-phase (I) and quadrature phase (Q) paths). In such an embodiment, RF input signal807fromFIG. 9may be down-converted to provide I and Q baseband output signals to be transmitted to the baseband processor.

In some embodiments, the LO signals may differ in duty cycle (the percentage of one period in which the LO signal is high) and/or offset (the difference between start points of the period). In some embodiments, the LO signals may have an 85% duty cycle and an 80% offset. In some embodiments, each branch of the mixer circuitry (e.g., the in-phase (I) and quadrature phase (Q) path) may operate at an 80% duty cycle, which may result in a significant reduction is power consumption.

The RF input signal807(FIG. 8) may comprise a balanced signal, although the scope of the embodiments is not limited in this respect. The I and Q baseband output signals may be provided to low-noise amplifier, such as amplifier circuitry906(FIG. 9) or to filter circuitry908(FIG. 9).

In some embodiments, the output baseband signals907and the input baseband signals911may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals907and the input baseband signals911may be digital baseband signals. In these alternate embodiments, the radio IC circuitry may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry.

In some embodiments, the synthesizer circuitry904may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry904may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. According to some embodiments, the synthesizer circuitry904may include digital synthesizer circuitry. An advantage of using a digital synthesizer circuitry is that, although it may still include some analog components, its footprint may be scaled down much more than the footprint of an analog synthesizer circuitry. In some embodiments, frequency input into synthesizer circuitry904may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. A divider control input may further be provided by either the baseband processing circuitry708a-b(FIG. 7) depending on the desired output frequency905. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table (e.g., within a Wi-Fi card) based on a channel number and a channel center frequency as determined or indicated by the example application processor710. The application processor710may include, or otherwise be connected to, one of the example security signal converter101or the example received signal converter103(e.g., depending on which device the example radio architecture is implemented in).

In some embodiments, synthesizer circuitry904may be configured to generate a carrier frequency as the output frequency905, while in other embodiments, the output frequency905may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the output frequency905may be a LO frequency (fLO).

FIG. 10illustrates a functional block diagram of baseband processing circuitry708ain accordance with some embodiments. The baseband processing circuitry708ais one example of circuitry that may be suitable for use as the baseband processing circuitry708a(FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example ofFIG. 10may be used to implement the example BT baseband processing circuitry708bofFIG. 7.

The baseband processing circuitry708amay include a receive baseband processor (RX BBP)1002for processing receive baseband signals1009provided by the radio IC circuitry706a-b(FIG. 7) and a transmit baseband processor (TX BBP)1004for generating transmit baseband signals1011for the radio IC circuitry706a-b. The baseband processing circuitry708amay also include control logic1006for coordinating the operations of the baseband processing circuitry708a.

In some embodiments (e.g., when analog baseband signals are exchanged between the baseband processing circuitry708a-band the radio IC circuitry706a-b), the baseband processing circuitry708amay include ADC1010to convert analog baseband signals1009received from the radio IC circuitry706a-bto digital baseband signals for processing by the RX BBP1002. In these embodiments, the baseband processing circuitry708amay also include DAC1012to convert digital baseband signals from the TX BBP1004to analog baseband signals1011.

The term “access point” (AP) as used herein may be a fixed station. An access point may also be referred to as an access node, a base station, an evolved node B (eNodeB), or some other similar terminology known in the art. An access terminal may also be called a mobile station, user equipment (UE), a wireless communication device, or some other similar terminology known in the art. Embodiments disclosed herein generally pertain to wireless networks. Some embodiments may relate to wireless networks that operate in accordance with one of the IEEE 802.11 standards.

Example 1 includes an apparatus for a non-Access Point Station (non-AP STA), comprising: RF interface circuitry; and processor circuitry coupled with the RF interface circuitry and configured to: monitor a trigger frame from an Access Point (AP) or ongoing uplink transmission from one or more non-AP STAB in a basic service set (BSS) associated with the AP and the non-AP STA to detect a location of a resource unit pre-allocated for transmission of urgent data; encode the urgent data for transmission to the AP via the RF interface circuitry on the resource unit, when the non-AP STA needs to transmit the urgent data; and pause the ongoing uplink transmission on the resource unit while continuing transmission of a pilot signal on the resource unit, when the non-AP STA does not need to transmit the urgent data.

Example 2 includes the apparatus of Example 1, wherein when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the processor circuitry is further configured to: monitor the trigger frame or the ongoing uplink transmission to detect an Orthogonal Frequency Division Multiple Access (OFDMA) symbol boundary and estimate a frequency offset of the non-AP STA relative to the AP or the ongoing uplink transmission; and compensate the frequency offset to synchronize with the AP or the ongoing uplink transmission.

Example 3 includes the apparatus of Example 1 or 2, wherein the resource unit comprises a pre-allocated blank symbol during the ongoing uplink transmission.

Example 4 includes the apparatus of Example 1 or 2, wherein the resource unit comprises a pre-allocated preemption gap during the ongoing uplink transmission.

Example 5 includes the apparatus of Example 4, wherein the preemption gap is followed by a midamble.

Example 6 includes the apparatus of Example 1 or 2, wherein when the non-AP STA needs to transmit the urgent data, the processor circuitry is configured to encode the urgent data for transmission to the AP by use of Non-Orthogonal Multiple Access (NOMA) technique.

Example 7 includes the apparatus of Example 6, wherein the non-AP STA is a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit is pre-allocated for the multiple non-AP STAs based on the NOMA group identifier.

Example 8 includes the apparatus of Example 6, wherein when the non-AP STA needs to transmit the urgent data, the processor circuitry is further configured to encode a NOMA signature pre-defined for identifying the non-AP STA for transmission to the AP via the RF interface circuitry on the resource unit.

Example 9 includes the apparatus of Example 1, wherein when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the processor circuitry is further configured to: monitor the trigger frame or the ongoing uplink transmission to detect a location of a pilot subcarrier and null out the location of the pilot subcarrier.

Example 10 includes an apparatus for an Access Point (AP), comprising: radio frequency (RF) interface circuitry; and processor circuitry coupled with the RF interface circuitry and configured to: track ongoing uplink transmission from one or more non-Access Point Stations (non-AP STAs) in a basic service set (BSS) of the AP based on pilot signals transmitted by the one or more non-AP STAs; and determine, based on a trigger frame from the AP or the ongoing uplink transmission, a location of a resource unit pre-allocated for a non-AP STA having urgent data to be transmitted to the AP; and decode the urgent data received from the non-AP STA via the RF interface circuit on the resource unit, wherein the pilot signals comprise a pilot signal transmitted on the resource unit by a non-AP STA having no urgent data to transmit.

Example 11 includes the apparatus of Example 10, wherein the resource unit comprises a pre-allocated blank symbol during the ongoing uplink transmission.

Example 12 includes the apparatus of Example 10, wherein the resource unit comprises a pre-allocated preemption gap during the ongoing uplink transmission.

Example 13 includes the apparatus of Example 12, wherein the preemption gap is followed by a midamble.

Example 14 includes the apparatus of Example 10, wherein the urgent data is transmitted by use of Non-Orthogonal Multiple Access (NOMA) technique.

Example 15 includes the apparatus of Example 14, wherein the non-AP STA having urgent data to transmit is a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit is pre-allocated for the multiple non-AP STAs based on the NOMA group identifier.

Example 16 includes the apparatus of Example 14, wherein the processor circuitry is configured to decode the urgent data based on a NOMA signature pre-defined for identifying the non-AP STA and received from the non-AP STA via the RF interface circuitry on the resource unit.

Example 17 includes the apparatus of Example 10, wherein the processor circuitry is further configured to: allocate a blank symbol during downlink transmission; and pause the downlink transmission during the black symbol to detect and decode the urgent data received from the non-AP STA.

Example 18 includes the apparatus of Example 17, wherein the processor circuitry is further configured to: encode a midamble after the blank symbol for transmission to the one or more non-AP STAs via the RF interface circuit.

Example 19 includes a method for a non-Access Point Station (non-AP STA), comprising: monitoring a trigger frame from an Access Point (AP) or ongoing uplink transmission from one or more non-AP STAs in a basic service set (BSS) associated with the AP and the non-AP STA to detect a location of a resource unit pre-allocated for transmission of urgent data; encoding the urgent data for transmission to the AP on the resource unit, when the non-AP STA needs to transmit the urgent data; and pausing the ongoing uplink transmission on the resource unit while continuing transmission of a pilot signal on the resource unit, when the non-AP STA does not need to transmit the urgent data.

Example 20 includes the method of Example 19, wherein when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the method further comprises: monitoring the trigger frame or the ongoing uplink transmission to detect an Orthogonal Frequency Division Multiple Access (OFDMA) symbol boundary and estimate a frequency offset of the non-AP STA relative to the AP or the ongoing uplink transmission; and compensating the frequency offset to synchronize with the AP or the ongoing uplink transmission.

Example 21 includes the method of Example 19 or 20, wherein the resource unit comprises a pre-allocated blank symbol during the ongoing uplink transmission.

Example 22 includes the method of Example 19 or 20, wherein the resource unit comprises a pre-allocated preemption gap during the ongoing uplink transmission.

Example 23 includes the method of Example 22, wherein the preemption gap is followed by a midamble.

Example 24 includes the method of Example 19 or 20, wherein when the non-AP STA needs to transmit the urgent data, the method comprises encoding the urgent data for transmission to the AP by use of Non-Orthogonal Multiple Access (NOMA) technique.

Example 25 includes the method of Example 24, wherein the non-AP STA is a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit is pre-allocated for the multiple non-AP STAs based on the NOMA group identifier.

Example 26 includes the method of Example 24, wherein when the non-AP STA needs to transmit the urgent data, the method further comprises: encoding a NOMA signature pre-defined for identifying the non-AP STA for transmission to the AP on the resource unit.

Example 27 includes the method of Example 19, wherein when the non-AP STA needs to transmit the urgent data, before transmission of the urgent data, the method further comprises: monitoring the trigger frame or the ongoing uplink transmission to detect a location of a pilot subcarrier and null out the location of the pilot subcarrier.

Example 28 includes a method for an Access Point (AP), comprising: tracking ongoing uplink transmission from one or more non-Access Point Stations (non-AP STAs) in a basic service set (BSS) of the AP based on pilot signals transmitted by the one or more non-AP STAs; and determining, based on a trigger frame from the AP or the ongoing uplink transmission, a location of a resource unit pre-allocated for a non-AP STA having urgent data to be transmitted to the AP; and decoding the urgent data received from the non-AP STA on the resource unit, wherein the pilot signals comprise a pilot signal transmitted on the resource unit by a regular non-AP STA having no urgent data to transmit.

Example 29 includes the method of Example 28, wherein the resource unit comprises a pre-allocated blank symbol during the ongoing uplink transmission.

Example 30 includes the method of Example 28, wherein the resource unit comprises a pre-allocated preemption gap during the ongoing uplink transmission.

Example 31 includes the method of Example 30, wherein the preemption gap is followed by a midamble.

Example 32 includes the method of Example 28, wherein the urgent data is transmitted by use of Non-Orthogonal Multiple Access (NOMA) technique.

Example 33 includes the method of Example 32, wherein the non-AP STA having urgent data to transmit is a member of a NOMA group including multiple non-AP STAs and having a NOMA group identifier, and the resource unit is pre-allocated for the multiple non-AP STAs based on the NOMA group identifier.

Example 34 includes the method of Example 32, further comprising: decoding the urgent data based on a NOMA signature pre-defined for identifying the non-AP STA and received from the non-AP STA on the resource unit.

Example 35 includes the method of Example 28, further comprising: allocating a blank symbol during downlink transmission; and pausing the downlink transmission during the black symbol to detect and decode the urgent data received from the non-AP STA.

Example 36 includes the method of Example 35, further comprising: encoding a midamble after the blank symbol for transmission to the one or more non-AP STAs.

Example 37 includes a computer-readable medium having instructions stored thereon, wherein the instructions, when executed by processor circuitry of a non-Access Point Station (non-AP STA), cause the processor circuitry to perform the method of any of Examples 19-27.

Example 38 includes an apparatus for a non-Access Point Station (non-AP STA), comprising means for performing the actions of the method of any of Examples 19-27.

Example 39 includes a computer-readable medium having instructions stored thereon, wherein the instructions, when executed by processor circuitry of an Access Point (AP), cause the processor circuitry to perform the method of any of Examples 28-36.

Example 40 includes an apparatus for an Access Point (AP) comprising means for performing the actions of the method of any of Examples 28-36.