Wireless device, method, and computer readable media for signaling a short training field in a high-efficiency wireless local area network

Apparatuses, methods, and computer readable media for signaling high efficiency short training field are disclosed. A high-efficiency wireless local-area network (HEW) station is disclosed. The HEW station may comprise circuitry configured to: receive a trigger frame comprising an allocation of a resource block for the HEW station, and transmit a high efficiency short training field (HE-STF) with a same bandwidth as a subsequent data portion, wherein the transmit is to be in accordance with orthogonal frequency division multiple access (OFDMA) and wherein the transmit is within the resource block. A subcarrier allocation for the HE-STF may matche a subcarrier allocation for the subsequent data portion. The HE-STF and the subsequent data portion may be transmitted with a same power. A total power of active subcarriers of the HE-STF may be equal to or proportional to a second total of data subcarriers and pilot subcarriers of the subsequent data portion.

TECHNICAL FIELD

Embodiments pertain to wireless communications in a wireless local-area network (WLAN) such as Institute of Electrical and Electronic Engineers (IEEE) 802.11. Some embodiments relate to signaling a high efficiency WLAN short training field (HE-STF). Some embodiments relate to using the HE-STF to determine an automatic gain control (AGC) for receiving subsequent data using orthogonal frequency division multiple-access (OFDMA).

BACKGROUND

Efficient use of the resources of a WLAN is important to provide bandwidth and acceptable response times to the users of the WLAN. However, often there are many devices trying to share the same resources and the devices may interfere with one another. Moreover, wireless devices may need to operate with both newer protocols and with legacy device protocols.

Thus there are general needs for systems and methods for signaling high efficiency signal fields that may be used to determine an AGC for receiving subsequent data.

DETAILED DESCRIPTION

FIG. 1illustrates a WLAN100in accordance with some embodiments. The WLAN may comprise a basis service set (BSS)100that may include a master station102, which may be an AP, a plurality of high-efficiency wireless (HEW) (e.g., IEEE 802.1 lax) STAs104and a plurality of legacy (e.g., IEEE 802.11n/ac) devices106.

The master station102may be an AP using the IEEE 802.11 to transmit and receive. The master station102may be a base station. The master station102may use other communications protocols as well as the IEEE 802.11 protocol. The IEEE 802.11 protocol may be IEEE 802.11ax. The IEEE 802.11 protocol may include using OFDMA, time division multiple access (TDMA), and/or code division multiple access (CDMA). The IEEE 802.11 protocol may include a multiple access technique. For example, the IEEE 802.11 protocol may include space-division multiple access (SDMA) and/or MU-MIMO.

The legacy devices106may operate in accordance with one or more of IEEE 802.11 a/g/ag/n/ac, IEEE 802.11-2012, or another legacy wireless communication standard. The legacy devices106may be STAs or IEEE STAs.

The HEW STAs104may be wireless transmit and receive devices such as cellular telephone, handheld wireless device, wireless glasses, wireless watch, wireless personal device, tablet, or another device that may be transmitting and receiving using the IEEE 802.11 protocol such as IEEE 802.11ax or another wireless protocol. In some embodiments, the HEW STAs104may be termed high efficiency (HE) stations.

The BSS100may operate on a primary channel and one or more secondary channels or sub-channels. The BSS100may include one or more master stations102. In accordance with some embodiments, the master station102may communicate with one or more of the HEW devices104on one or more of the secondary channels or sub-channels or the primary channel. In accordance with some embodiments, the master station102communicates with the legacy devices106on the primary channel. In accordance with some embodiments, the master station102may be configured to communicate concurrently with one or more of the HEW STAs104on one or more of the secondary channels and a legacy device106utilizing only the primary channel and not utilizing any of the secondary channels.

The master station102may communicate with legacy devices106in accordance with legacy IEEE 802.11 communication techniques. In example embodiments, the master station102may also be configured to communicate with HEW STAs104in accordance with legacy IEEE 802.11 communication techniques. Legacy IEEE 802.11 communication techniques may refer to any IEEE 802.11 communication technique prior to IEEE 802.11 ax.

In some embodiments, a HEW frame may be configurable to have the same bandwidth as a sub-channel, and the bandwidth may be one of 20 MHz, 40 MHz, or 80 MHz, 160 MHz, 320 MHz contiguous bandwidths or an 80+80 MHz (160 MHz) non-contiguous bandwidth. In some embodiments, bandwidths of 1 MHz, 1.25 MHz, 2.0 MHz, 2.5 MHz, 5 MHz and 10 MHz, or a combination thereof or another bandwidth that is less or equal to the available bandwidth, may also be used. A HEW frame may be configured for transmitting a number of spatial streams, which may be in accordance with MU-MIMO.

In other embodiments, the master station102, HEW STA104, and/or legacy device106may also implement different technologies such as code division multiple access (CDMA) 2000, CDMA 2000 1X, CDMA 2000 Evolution-Data Optimized (EV-DO), Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Long Term Evolution (LTE), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), BlueTooth®, or other technologies.

Some embodiments relate to HEW communications. In accordance with some IEEE 802.11 ax embodiments, a master station102may operate as a master station which may be arranged to contend for a wireless medium (e.g., during a contention period) to receive exclusive control of the medium for an HEW control period. In some embodiments, the HEW control period may be termed a transmission opportunity (TXOP). The master station102may transmit a HEW master-sync transmission, which may be a trigger frame or HEW control and schedule transmission, at the beginning of the HEW control period. The master station102may transmit a time duration of the TXOP and sub-channel information. During the HEW control period, HEW STAs104may communicate with the master station102in accordance with a non-contention based multiple access technique such as OFDMA or MU-MIMO. This is unlike conventional WLAN communications in which devices communicate in accordance with a contention-based communication technique, rather than a multiple access technique. During the HEW control period, the master station102may communicate with HEW stations104using one or more HEW frames. During the HEW control period, the HEW STAs104may operate on a sub-channel smaller than the operating range of the master station102. During the HEW control period, legacy stations refrain from communicating. In accordance with some embodiments, during the master-sync transmission the HEW STAs104may contend for the wireless medium with the legacy devices106being excluded from contending for the wireless medium during the master-sync transmission.

In some embodiments, the multiple-access technique used during the HEW control period may be a scheduled OFDMA technique, although this is not a requirement. In some embodiments, the multiple access technique may be a time-division multiple access (TDMA) technique or a frequency division multiple access (FDMA) technique. In some embodiments, the multiple access technique may be a space-division multiple access (SDMA) technique.

The master station102may also communicate with legacy stations106and/or HEW stations104in accordance with legacy IEEE 802.11 communication techniques. In some embodiments, the master station102may also be configurable to communicate with HEW stations104outside the HEW control period in accordance with legacy IEEE 802.11 communication techniques, although this is not a requirement.

In example embodiments, the master station102and/or HEW stations104are configured to perform one or more of the functions and/or methods described herein in conjunction withFIGS. 1-7such as transmitting and receiving HE-SIGs and using the received HE-SIG to determine an AGC for receiving a subsequent data field.

FIG. 2illustrates a preamble structure200in accordance with some embodiments. Illustrated inFIG. 2are a legacy short training field (L-STF)202, a legacy long training field (L-LTF)204, a legacy signal field (L-SIG)206, a very-high throughput signal A field (VHT-SIG-A)208, a VHT-SIG-B210, a very-high throughput short training field (VHT-STF)212, a very-high throughput long training field (VHT-LTF)214, a second VHT-LTF216, a second VHT-SIG-B218, and a data field220.

The L-STF202and the L-LTF204may be 12 orthogonal frequency division multiplexing (OFDM) symbols that may include information for synchronizing timers, selecting antennas, or other information. The L-SIG field206may be used to describe the data rate and length of the frame. The VHT-SIG-A208field and VHT-SIG-B210field may be only used by master stations102, HEW stations104, and legacy devices106that are configured to operate in accordance with IEEE 802.11 ac.

The VHT-STF212may be a field to help the master station102, HEW station104, and/or legacy device106tune in the signal. The VHT-LTF214may be a field that comprises a sequence of symbols that set up demodulation of the rest of the frame. The second VHT-LTF216may be a duplicate of the VHT-LTF214or include additional information. The VHT-SIG-B218may be a duplicate of the VHT-SIG-B210or may contain additional information. The data field222may comprise higher layer packets which may include an aggregate frame comprising multiple higher-layer packets.

The master stations102, HEW stations104, and legacy devices106may be configured with AGC for OFDMA. The AGC may use the energy estimated from a short training field such as L-STF202or VHT-STF212to adjust the signal path gain and make the AGC loop converged in order to lower the analog to digital clipping and quantization noise.

FIG. 3illustrates a HE-STF304in accordance with some embodiments. Illustrated inFIG. 3are a station302, a HE-STF304, and a HE-STF ¼ down sampled306. The frequency308,310,312is illustrated along a horizontal axis for the station302, the HE-STF304, and the HE-STF ¼ down sampled306, respectively. The station302may be a master station102or a HEW station104. The scheduled subchannel320indicates a subchannel that is scheduled for the station302for a downlink transmission. The scheduled subchannel320may have been indicated in a trigger frame received by the scheduled station302. The scheduled subchannel320may be a portion of an 80 MHz bandwidth. For example, the subchannel320may be 2.5 MHz or another bandwidth less than or equal to 80 MHz.

The HEW STF304may be for a bandwidth of 80 MHz. The HE-STF304is a subcarrier allocation. The HE-STF304may be used for IEEE 802.11ac. In some embodiments the HE-STF304is a subcarrier allocation that may be used in IEEE 802.11ax. The symbol duration in IEEE 802.11ax may be four times longer than in IEEE 802.11ac. The arrows indicate subcarriers350. Subcarriers318are within the scheduled subchannel320. In some embodiments subcarriers may be termed tones. In some embodiments arrows that are not ghosted may be active subcarriers and arrows that are ghosted are part of a subcarrier pattern but are not active. For example, subcarrier515(FIG. 5) is ghosted so it may be part of a subcarrier pattern, but may not be active.

In some embodiments beam forming may be used to send the scheduled subchannel320portion of the HE-STF304to the station302. If beamforming is used in the downlink, then the station302may receive littler power from other portions of the HE-STF304except the subchannel320portion. The station302may only receive the subcarriers318that are included in the scheduled subchannel320portion of the scheduled subchannel320.

The station302may not be able to predict the total received power of the data portion (e.g.,220ofFIG. 2) because the subcarriers318of the HE-STF304are not dense enough in the subchannel320for an accurate estimation of the power. For example, as illustrated, there are only four subcarriers318in the subchannel320. The HE-STF304may include a portion of the scheduled subchannel320where there are no subcarriers316.

For each resource allocation such as the subchannel320the total power of both the data subcarriers (e.g., the subcarriers of data220ofFIG. 2) and the pilot subcarriers should be equal to or proportionally represented by the total power of the corresponding HE-STF304tones for the station320to improve the AGC.

The HE-STF ¼ down sampled306may be subcarriers314that are a sampling density in frequency of every 16 subcarriers of the HE-STF304. In some embodiments other sampling densities may be used. The subcarriers314may have a 4× symbol duration in comparison with IEEE 802.11ac. The subcarriers314of the HE-STF ¼ down sampled306may mean that only one subcarrier314may be within the scheduled subchannel320. Having only one subcarrier314in the scheduled subchannel320may cause the AGC measurement for the station302to have an energy mismatch between the portion of the HE-STF304within the scheduled subchannel320and the data (e.g. data220ofFIG. 2). The HE-STF ¼ down sampled306may increase repetition in time and compensate for DC offset.

FIG. 4illustrates a HE-STF404subcarrier allocation in accordance with some embodiments. Illustrated inFIG. 4are a station402, and a HE-STF404. The frequency410,412is illustrated along a horizontal axis for the station402and HE-STF404, respectively. The arrows indicate subcarriers450. The station402may be a master station102or a HEW station104. The scheduled subchannel420indicates a subchannel that is scheduled for the station402for a downlink transmission. The scheduled subchannel420may have been indicated in a trigger frame received by the scheduled station402. The scheduled subchannel420may be a portion of an 80 MHz bandwidth. For example, the subchannel420may be 2.5 MHz or another bandwidth less than the 80 MHz. The scheduled subchannel420may be a subchannel that is contended for in a trigger frame random channel access period.

The subcarriers450that are active in an allocated subchannel such as scheduled subchannel420may be termed the active STF subcarriers. For example tone414within scheduled subchannel420may be termed an active STF subcarrier. In some embodiments the subcarriers450such as subcarriers414,415may be distributed so that each allocation block, unit, sub-band, and/or sub-channel with the same bandwidth has a similar number of subcarriers414,415. The subcarriers414,415may be evenly distributed across the usable subcarriers except the DC and edge subcarriers. The subcarriers414,415being evenly distributed across the usable subcarriers may enable the station402to improve AGC measurement. The subcarriers414,415being nearly evenly distributed across the usable tones may enable the station402to improve AGC measurement.

In some embodiments the HE-STF404may have the same bandwidth as an allocated bandwidth in which data is transmitted. In some embodiments the station402may transmit a HE-STF (not illustrated) in the uplink with a same bandwidth as an allocated or scheduled subchannel. For example, station402may transmit a HE-STF with a bandwidth that is the same as the bandwidth of the scheduled subchannel420.

In some embodiments a master station102may transmit the HE-STF404to the station402using beam forming and the station402may only receive the scheduled subchannel420portion without significant attenuation. The master station102may then transmit a subsequent data portion on the same scheduled subchannel420. The master station102may use a same subcarrier pattern for the HE-STF404within the scheduled subchannel420as for a subsequent data portion within the subchannel420. The master station102may transmit the HE-STF404using a bandwidth that is greater than the bandwidth of the scheduled subchannel420and which may be the same bandwidth as a subsequent data portion which may be to more than one station402and which uses OFDMA.

In the uplink, the station402may transmit the subcarrier414only as a HE-STF404to the master station102. The station402may then transmit a subsequent data portion using OFDMA to the master station102using subcarriers414within the scheduled subchannel. In some embodiments a same subcarrier pattern is used for the HE-STF404as for the subsequent data portion.

The signal power of the active subcarriers (e.g.,450,414,415) of the HE-STF404within the scheduled subchannel420may match or be proportional to the total power within the scheduled subchannel420for the subsequent data portion. The master station102and/or the HEW station104may use the subcarriers414to determine the AGC setting for receiving the subsequent data portion.

Using the same subcarrier pattern for both the HE-STF404and the subsequent data portion in either an uplink transmission or a downlink transmission may have the technical effect of the receiver experiencing the same channel attenuation which may improve the AGC setting.

FIG. 5illustrates a HE-STF504active subcarrier allocation in accordance with some embodiments. Illustrated inFIG. 5are station502, HE-STF504, resource block1520.1, resource block2520.2, and resource block3520.3. The frequency514,516is along a horizontal axis for the station502and the HE-STF504, respectively. The station502may be a master station102or HEW station104. Subcarriers550such as subcarrier512may be subcarriers that are active. The ghosted arrow at514may be an inactive or muted subcarrier514.

The resource blocks520may be resource blocks allocated to the station102for uplink or downlink transmission. In some embodiments the resource blocks520may be allocated to more than one station502.

The station502may be allocated the resource blocks520in a trigger frame for uplink or downlink transmission to a master station102. In some embodiments the resource blocks520may be one or more subchannels the station102is transmitting on in the uplink. For example, the station502may have received a trigger frame for random access and determined to transmit within the resource blocks520. In some embodiments the resource blocks520may be contiguous.

Each of the resource blocks520may have the same number of subcarriers such as26,56,30, or32, or there may be a fixed number of subcarriers for different sized resource blocks520. The station502may transmit the HE-STF104in a same patter for each of the resource blocks520. For example as illustrated the station502transmits four subcarriers550such as subcarrier512for resource block2520.2. The station502may alter the pattern to leave a subcarrier inactive or mute a subcarrier550at an edge of the bandwidth or at the DC506. For example, muted subcarrier514.

In some embodiments the tones550or active subcarriers are transmitted on even subcarriers so that the HE-STF504may be repeated in the time domain which may assist the receiver in estimating the DC offset. The spacing508,510between the tones550may be the same.

In some embodiments the HE-STF504tone allocation will match the tone allocation in the OFDMA allocation. In some embodiments every resource block220has at last two tones. In some embodiments the HEW device104is configured to transmit a separate HE-STF504in each resource block520.

FIG. 6illustrates a ¼ down sampled HE-STF604active subcarrier allocation in accordance with some embodiments. Illustrated inFIG. 6are scheduled station602and ¼ down sampled HE-STF604. The frequency614,616is along a horizontal axis for the scheduled station602and ¼ down sampled HE-STF604, respectively.

The scheduled station602may include a resource block for scheduled station1620and a resource block for scheduled station0622. Subcarriers650such as subcarrier606and subcarrier607are active subcarriers and are indicated with up arrows. The scheduled station602, which as illustrated are station1and station0, may be a master station102or HEW station. Resource block for station1620may be a resource block of an allocation for station1. Resource block for station0622may be a resource block for an allocation for station0. The ¼ down sampled HE-STF602may be a down sampling of the HE-STF transmission of the scheduled station602or may be the received signals of the scheduled station602which was transmitted by a master station102or HEW station104.

Down sampling may change the ratio between the number of subcarriers650in a HE-STF and the corresponding data portion of the subcarriers650. Resource block for scheduled station0622has only one subcarrier607and may have 32 data portion subcarriers while the resource block for scheduled station1620of the same size as resource block for scheduled station0622has two active tones606. In some embodiments the scheduled station602are configured to adjust the power used for the subcarrier607for the HE-STF when the number of active subcarriers607varies. For example, station0may transmit active subcarrier607with twice the power as station0transmits active subcarriers606. The power compensation may be used both in the uplink by station0and in a downlink transmission by a master station102where the subcarrier607indicates a subcarrier received by station0.

For uplink transmissions or for downlink transmissions the scheduled station102may have a small allocated resource block such as subchannel of 2.5 MHz.

FIG. 7illustrates a HEW device in accordance with some embodiments. HEW device700may be an HEW compliant device that may be arranged to communicate with one or more other HEW devices, such as HEW STAs104(FIG. 1) or master station102(FIG. 1) as well as communicate with legacy devices106(FIG. 1). HEW STAs104and legacy devices106may also be referred to as HEW devices and legacy STAs, respectively. HEW device700may be suitable for operating as master station102(FIG. 1) or a HEW STA104(FIG. 1). In accordance with embodiments, HEW device700may include, among other things, a transmit/receive element701(for example an antenna), a transceiver702, physical (PHY) circuitry704, and media access control (MAC) circuitry706. PHY circuitry704and MAC circuitry706may be HEW compliant layers and may also be compliant with one or more legacy IEEE 802.11 standards. MAC circuitry706may be arranged to configure packets such as a physical layer convergence procedure (PLCP) protocol data unit (PPDUs) and arranged to transmit and receive PPDUs, among other things. HEW device700may also include circuitry708and memory710configured to perform the various operations described herein. The circuitry708may be coupled to the transceiver702, which may be coupled to the transmit/receive element701. WhileFIG. 7depicts the circuitry708and the transceiver702as separate components, the circuitry708and the transceiver702may be integrated together in an electronic package or chip.

In some embodiments, the MAC circuitry706may be arranged to contend for a wireless medium during a contention period to receive control of the medium for the HEW control period and configure an HEW PPDU. In some embodiments, the MAC circuitry706may be arranged to contend for the wireless medium based on channel contention settings, a transmitting power level, and a CCA level.

The PHY circuitry704may be arranged to transmit the HEW PPDU. The PHY circuitry704may include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the circuitry708may include one or more processors. The circuitry708may be configured to perform functions based on instructions being stored in a RAM or ROM, or based on special purpose circuitry. The circuitry708may be termed processing circuitry in accordance with some embodiments. The circuitry708may include a processor such as a general purpose processor or special purpose processor. The circuitry708may implement one or more functions associated with transmit/receive elements701, the transceiver702, the PHY circuitry704, the MAC circuitry706, and/or the memory710.

In some embodiments, the circuitry708may be configured to perform one or more of the functions and/or methods described herein and/or in conjunction withFIGS. 1-7such as transmitting and receiving HE-SIGs and using the received HE-SIG to determine an AGC for receiving a subsequent data field.

In some embodiments, the transmit/receive elements701may be two or more antennas that may be coupled to the PHY circuitry704and arranged for sending and receiving signals including transmission of the HEW packets. The transceiver702may transmit and receive data such as HEW PPDU and packets that include an indication that the HEW device700should adapt the channel contention settings according to settings included in the packet. The memory710may store information for configuring the other circuitry to perform operations for configuring and transmitting HEW packets and performing the various operations to perform one or more of the functions and/or methods described herein and/or in conjunction withFIGS. 1-7such as transmitting and receiving HE-SIGs and using the received HE-SIG to determine an AGC for receiving a subsequent data field.

In some embodiments, the HEW device700may be configured to communicate using OFDM communication signals over a multicarrier communication channel. In some embodiments, HEW device700may be configured to communicate in accordance with one or more specific communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) standards including IEEE 802.11-2012, 802.11n-2009, 802.11ac-2013, 802.11ax, DensiFi, standards and/or proposed specifications for WLANs, or other standards as described in conjunction withFIG. 1, although the scope of the invention is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. In some embodiments, the HEW device700may use 4× symbol duration of 802.11n or 802.11 ac.

In some embodiments, an HEW device700may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), an access point, a base station, a transmit/receive device for a wireless standard such as 802.11 or 802.16, or other device that may receive and/or transmit information wirelessly. In some embodiments, the mobile device may include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be an LCD screen including a touch screen.

The following examples pertain to further embodiments. Example 1 is an apparatus of an apparatus of a high-efficiency wireless local-area network (HEW) station. The HEW station including circuitry configured to: receive a trigger frame comprising an allocation of a resource block for the HEW station; and transmit a high efficiency short training field (HE-STF) with a same bandwidth as a subsequent data portion, where the HE-STF is to be transmitted in accordance with orthogonal frequency division multiple access (OFDMA) and where the bandwidth is indicated in the allocation and is less than 20 MHz.

In Example 2, the subject matter of Example 1 can optionally include where a subcarrier allocation for the HE-STF matches a subcarrier allocation for the subsequent data portion.

In Example 3, the subject matter of Examples 1 or 2 can optionally include where the HE-STF and the subsequent data portion are transmitted with a same power.

In Example 4, the subject matter of any of Examples 1-3 can optionally include where a total power of active subcarriers of the HE-STF are equal to or proportional to a second total of data subcarriers and pilot subcarriers of the subsequent data portion.

In Example 5, the subject matter of any of Examples 1-4 can optionally include wherein the bandwidth is one from the following group: 1.25 MHz, 2 MHz, 2.5 MHz, 5 MHz, and 10 MHz.

In Example 6, the subject matter of any of Examples 1-5 can optionally include where a subcarrier pattern of the HE-STF is the same as a subcarrier pattern of the data portion.

In Example 7, the subject matter of any of Examples 1-6 can optionally include where the HE-STF comprises at least two active subcarriers for the resource block.

In Example 8, the subject matter of any of Examples 1-7 can optionally include where the allocation comprises one or more additional resource blocks for the HEW station.

In Example 9, the subject matter of Example 8 can optionally include where the resource block and the one or more additional resource blocks have a same subcarrier pattern for the HE-STF.

In Example 10, the subject matter of Example 8 can optionally include where the circuitry is further configured to transmit a separate HE-STF within each of the one or more additional resource blocks.

In Example 11, the subject matter of Example 8 can optionally include where the HE-STF and the allocation and the one or more additional allocations have a same bandwidth.

In Example 12, the subject matter of any of Examples 1-11 can optionally include where the HE-STF comprises one or more subcarriers, and where the one or more subcarriers are transmitted at a higher power to compensate for one or more muted subcarriers, where the one or more muted subcarriers are muted for one of the reasons from the following group: an out-of-band emission, peak to average power ratio (PAPR) reduction, and DC.

In Example 13, the subject matter of any of Examples 1-12 can optionally include where the HE-STF comprises a plurality of evenly spaced subcarriers.

In Example 14, the subject matter of any of Examples 1-13 can optionally include where the HE-STF comprises at least one subcarrier transmitted with a greater power than other subcarriers to compensate for a lower number of subcarriers in a portion of the resource block.

In Example 15, the subject matter of any of Examples 1-14 can optionally include where the circuitry is further configured to: receive a second allocation of a second resource block, wherein the second allocation is for a downlink transmission from a master station; and receive a second HE-STF with a second same bandwidth as a bandwidth of a total allocation of a plurality of HEW stations, wherein the HEW station is one of the plurality of HEW stations and wherein each subchannel of the total allocation has a same or proportional power.

In Example 16, the subject matter of Example 15 can optionally include where the circuitry is further configured to determine an automatic gain control (AGC) from the second HE-STF, and wherein the AGC is for a subsequent data portion.

In Example 17, the subject matter of any of Examples 1-16 can optionally include where a pattern of subcarriers is repeated for at least two of a plurality of sub-channels of the resource block.

In Example 18, the subject matter of Example 17 can optionally include where a spacing between subcarriers of the at least two of the plurality of subchannels is a same frequency.

In Example 19, the subject matter of any of Examples 1-18 can optionally include where active subcarriers of the HE-STF are one-quarter down sampled in comparison to the subsequent data portion, and where at least one of the active subcarriers is power compensated due to a fewer number of active subcarriers within a subchannel of the resource allocation.

In Example 20, the subject matter of any of Examples 1-19 can optionally include memory coupled to the circuitry; and, one or more antennas coupled to the circuitry.

In Example 21, the subject matter of any of Examples 1-20 can optionally include where the circuitry further comprises processing circuitry and transceiver circuitry.

Example 22 is a method performed on a wireless local-area network (HEW) station. The method including receiving a trigger frame comprising an allocation of a resource block for the HEW station; and transmitting a high efficiency short training field (HE-STF) with a same bandwidth as a subsequent data portion, wherein the HE-STF is to be transmitted in accordance with orthogonal frequency division multiple access (OFDMA).

In Example 23, the subject matter of Example 22 can optionally include where a subcarrier allocation for the HE-STF matches a subcarrier allocation for the subsequent data portion.

Example 24 is a non-transitory computer-readable storage medium that stores instructions for execution by one or more processors on a wireless communication device. The operations configure the wireless communication device to: receive a trigger frame comprising an allocation of a resource block for the HEW station; and transmit a high efficiency short training field (HE-STF) with a same bandwidth as a subsequent data portion, wherein the HE-STF is to be transmitted in accordance with orthogonal frequency division multiple access (OFDMA).

In Example 25, the subject matter of Example 24 can optionally include where the HE-STF and the subsequent data portion are transmitted with a same power.