TW201703452A - Orthogonal training field sequences - Google Patents

Abstract

Aspects of the present disclosure provide techniques for phase tracking in wireless communications using frames with some portions that use relatively long symbol durations.

Description

Orthogonal training field sequence

Priority is claimed based on the patent law: this patent application claims US Provisional Patent Application No. 62/188,331 (Attorney Docket No. 154012 USL02) filed on July 2, 2015, and filed on July 8, 2015. U.S. Provisional Patent Application Serial No. 62/190,245 (Attorney Docket No. 154 012 US L03), each of which is hereby incorporated by reference in its entirety in its entirety in its entirety in its entirety herein in

Some aspects of the present content are generally related to wireless communication and, more specifically, to phase tracking as the training field increases in symbol duration.

Wireless communication networks are widely deployed to provide a variety of communication services such as voice, video, packet data, messaging, broadcast, and the like. The wireless networks may be multiplexed networks capable of supporting multiple users via sharing of available network resources. Examples of such multiplexed networks include code division multiplex access (CDMA) networks, time division multiplex access (TDMA) networks, frequency division multiplex access (FDMA) networks, and orthogonal FDMA ( OFDMA) Network and Single Carrier FDMA (SC-FDMA) networks.

In order to address the need for greater coverage and increased communication range, various solutions are being developed. One such scheme is the sub-1 GHz frequency range being developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11ah task force (eg, operating in the US in the 902-928 MHz range). Such development is a desire to utilize a frequency range that has a larger wireless range than a wireless range associated with other IEEE 802.11 technologies and has potentially fewer problems associated with path loss due to obstacles. drive.

The systems, methods and equipment of this case have several aspects, and there is no single aspect that is solely responsible for its desired attributes. Some features will now be briefly discussed, without limiting the scope of the present disclosure as expressed in the appended claims. After considering this discussion, and particularly after reading the section entitled "Implementation," it will be appreciated how the features of the present content provide advantages including improved communication in a wireless network.

Aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes a processing system configured to generate a frame having one or more training fields in which the pilot frequency symbols are to be transmitted via one or more tones; And an interface for outputting the frame for transmission.

Aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes an interface for acquiring a frame having one or more training fields in which the pilot frequency symbols are transmitted on one or more tones; and a processing system And configured to perform channel estimation for the frame based on the training fields and perform phase tracking based on the pilot symbols.

Aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes a processing system configured to generate a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream; and an interface for output The frame is transmitted for single-user (SU) transmission, downlink multi-user (MU) multiple-input multiple-output (MIMO) transmission, or orthogonal frequency division multiplexing access (OFDMA) transmission.

Aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes an interface for acquiring a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream, the frame being a single user (SU) Transmission, downlink multi-user (MU) multiple input multiple output (MIMO) transmission or orthogonal frequency division multiplexing access (OFDMA) transmission is obtained; and processing system configured to be based on the training fields The sequence performs channel estimation for the frame and performs phase tracking based on the pilot symbols.

Aspects of the present disclosure also provide various methods, other devices, and computer readable media that are capable of performing the operations described above and herein.

To achieve the foregoing and related ends, one or more aspects include features that are fully described below and particularly pointed out in the claims. The following description and the annexed drawings set forth in the claims However, the features indicate several of the various ways in which the principles of the various aspects may be employed, and the description is intended to include all such aspects and their equivalents.

The aspect of the present disclosure is generally related to wireless communication and, more specifically, to the phase and/or carrier frequency that can be used for wireless packets that use extended symbol duration (eg, 2x and/or 4x symbol duration). Offset (CFO) technique for tracking. This technique can help determine which tones are assigned to transmit pilot signals in LTFs that use extended symbol durations, such as 2x and 4x High Efficiency (HE) LTFs. This allocation can be defined via what is commonly referred to as a "tone map" which indicates the number and location of tones to be used to transmit the pilot signal.

Various aspects of the present content are described more fully below with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as being limited to any particular structure or function presented. Rather, these aspects are provided so that this disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed by those skilled in the art. Based on the teachings herein, those skilled in the art will appreciate that the scope of the present disclosure is intended to cover any aspect of the present disclosure as disclosed herein, regardless of whether the aspects are implemented independently or in combination with any other aspect. . For example, a device may be implemented or a method may be implemented using any number of aspects set forth herein. In addition, the scope of the present disclosure is intended to cover such a device that is implemented using other structures, functions, or structures and functions other than the various aspects of the present disclosure as described herein or in various aspects of the present disclosure. Or method. It should be understood that any aspect of the present disclosure disclosed herein may be embodied by one or more elements of the claim.

This document uses the term "exemplary" to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

Although specific aspects are described herein, many variations and permutations of such aspects are within the scope of the present disclosure. Although some of the benefits and advantages of the preferred aspects are mentioned, the scope of the present disclosure is not intended to be limited to a particular benefit, use, or objective. Rather, the aspects of the present disclosure are intended to be broadly applicable to different wireless technologies, system configurations, networks, and transmission protocols, some of which are illustrated in the drawings and in the following description of the preferred aspects. The detailed description and drawings are merely illustrative of the scope of the present invention

The techniques described herein can be used in a variety of broadband wireless communication systems, including communication systems based on orthogonal multiplexing schemes. Examples of such communication systems include a sub-space multiplex access (SDMA) system, a time division multiplex access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and single carrier frequency division multiplexing access. (SC-FDMA) system. SDMA systems can utilize a sufficiently different direction to simultaneously transmit data belonging to multiple user terminals. The TDMA system can allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to a different user terminal. The OFDMA system uses orthogonal frequency division multiplexing (OFDM), which is a modulation technique that divides the overall system bandwidth into multiple orthogonal subcarriers. The secondary carriers may also be referred to as tones, frequency bands, and the like. For OFDM, data can be used to independently modulate each subcarrier. SC-FDMA systems may use interleaved FDMA (IFDMA) to transmit on subcarriers distributed across system bandwidth, use local FDMA (LFDMA) for transmission on a neighboring subcarrier, or use enhanced FDMA (EFDMA) ) to transmit on multiple adjacent subcarriers. Typically, modulating symbols are transmitted in the frequency domain using OFDM and modulated symbols are transmitted in the time domain using SC-FDM.

The teachings herein may be incorporated into (eg, implemented within or performed by) various wired or wireless devices (eg, nodes). In some aspects, a wireless node implemented in accordance with the teachings herein can include an access point or an access terminal.

An access point ("AP") may be implemented, or referred to as a Node B, a Radio Network Controller ("RNC"), an evolved Node B (eNB), a Base Station Controller ("BSC"), Base Station Transceiver ("BTS"), Base Station ("BS"), Transceiver Function Unit ("TF"), Radio Router, Radio Transceiver, Basic Service Set ("BSS"), Extended Service Set ("ESS "), radio base station ("RBS") or some other terminology.

An access terminal ("AT") may be included, implemented as, or referred to as a subscriber station, subscriber unit, mobile station (MS), remote station, remote terminal, user terminal (UT), user agent , user device, user equipment (UE), user station or some other terminology. In some implementations, the access terminal can include a cellular telephone, a wireless telephone, a Session Initiation Protocol ("SIP") telephone, a Wireless Area Loop ("WLL") station, a Personal Digital Assistant ("PDA"), with a wireless connection Capable handheld devices, stations (such as "AP STAs" that act as APs, or "STAs" that are not "AP STAs") or some other suitable processing device that is connected to a wireless data modem. Thus, one or more aspects taught herein can be incorporated into a telephone (eg, a cellular or smart phone), a computer (eg, a laptop), a tablet computer, a portable communication device, Portable computing device (eg, personal data assistant), entertainment device (eg, music or video device, or satellite radio), global positioning system (GPS) device, or any other configured to communicate via wireless or wired media Appropriate equipment. In some aspects, the AT can be a wireless node. Such a wireless node may provide, for example, a connection to a network (e.g., a wide area network such as the Internet or a cellular network) or a connection to the network via a wired or wireless communication link. Example wireless communication system

FIG. 1 illustrates a system 100 in which aspects of the present content can be performed. For example, any of the wireless stations including access point 110 and/or user terminal 120 can be located in a proximity aware network (NAN). The wireless station may exchange fine timing measurement (FTM) information for ranging during periods when the wireless station has been scheduled to wake up (eg, during a paging window or data window), and may use existing frames (eg, , Associated Frame, Trigger/Poll Frame, Probe Request/Probe Response Frame to exchange FTM information. In various aspects, one of the wireless devices can act as a ranging agent.

System 100 can be, for example, a multiplexed access multiple input multiple output (MIMO) system 100 having an access point and a user terminal. For the sake of simplicity, only one access point 110 is illustrated in FIG. An access point is typically a fixed station that communicates with a user terminal and may also be referred to as a base station or some other terminology. The user terminal can be fixed or mobile and can also be referred to as a mobile station, a wireless device, or some other terminology. Access point 110 can communicate with one or more user terminals 120 on the downlink and uplink at any given time. The downlink (ie, the forward link) is the communication link from the access point to the user terminal, and the uplink (ie, the reverse link) is the communication from the user terminal to the access point. link. The user terminal can also communicate with another user terminal in the same level.

System controller 130 can provide coordination and control for such APs and/or other systems. The APs may be managed by system controller 130, for example, system controller 130 may handle adjustments to radio frequency power, channels, authentication, and security. System controller 130 can communicate with the AP via a loadback. The APs can also communicate with each other directly or indirectly via wireless or wired backhaul.

Although portions of the following disclosure will describe user terminals 120 that are capable of communicating via sub-space multiplex access (SDMA), for some aspects, user terminal 120 may also include some user terminals that do not support SDMA. Thus, for such aspects, AP 110 can be configured to communicate with both SDMA and non-SDMA user terminals. The method can conveniently allow older versions of user terminals ("legacy" stations) to remain deployed in the enterprise, extending their useful life while allowing for the introduction of newer SDMA user terminals as deemed appropriate.

System 100 employs multiple transmit antennas and multiple receive antennas for data transmission on the downlink and uplink. Access point 110 is equipped with The antennas represent multiple inputs (MI) for downlink transmissions and multiple outputs (MO) for uplink transmissions. A group The selected user terminals 120 collectively represent multiple outputs for downlink transmissions and multiple inputs for uplink transmissions. For pure SDMA, if The data symbol stream of the user terminals is not covered by code, frequency or time by some means, and it is desirable to have . If the TDMA technique can be used, the code channel stream is multiplexed using different code channels in the case of CDMA, and the disjoint subband sets are used in the case of OFDM, Can be greater than . Each selected user terminal transmits user-specific data to the access point and/or receives user-specific data from the access point. In general, each selected user terminal can be equipped with one or more antennas (ie, 1). The selected user terminals may have the same or different number of antennas.

System 100 can be a time division duplex (TDD) system or a frequency division duplex (FDD) system. For TDD systems, the downlink and uplink share the same frequency band. For FDD systems, the downlink and uplink use different frequency bands. The MIMO system 100 can also transmit using a single carrier or multiple carriers. Each user terminal can be equipped with a single antenna (eg, to keep costs down) or multiple antennas (eg, where additional cost can be supported). If the user terminal 120 shares the same frequency channel by dividing the transmission/reception into different time slots, each time slot being assigned to a different user terminal 120, the system 100 may also be a TDMA system.

2 illustrates example elements of AP 110 and UT 120 illustrated in FIG. 1, which may be used to implement aspects of the present disclosure. One or more elements of AP 110 and UT 120 may be used to implement aspects of the present disclosure. For example, antenna 224, Tx/Rx 222 and/or processors 210, 220, 240, 242 of AP 110 and/or antenna 252, Tx/Rx 254, processors 260, 270, 288 of controller 230 or UT 120 and 290 and/or control 280 can be used to perform operations 700 and 700A as described herein and illustrated with reference to Figures 7 and 7A, respectively, and operations 900 and 900A described herein and illustrated with reference to Figures 9 and 9A, respectively.

2 illustrates a block diagram of an access point 110 and two user terminals 120m and 120x in a MIMO system 100. Access point 110 is equipped with Antennas 224a through 224ap. The user terminal 120m is equipped with Antennas 252ma to 252mu, and the user terminal 120x is equipped with Antennas 252xa to 252xu. Access point 110 is the transmitting entity for the downlink and the receiving entity for the uplink. Each user terminal 120 is a transmitting entity for the uplink and a receiving entity for the downlink. As used herein, a "sending entity" is an independently operated device or device capable of transmitting data via a wireless channel, and a "receiving entity" is an independently operated device or device capable of receiving data via a wireless channel. In the following description, the subscript " dn " indicates the downlink, the subscript " up " indicates the uplink, N _up user terminals are selected for simultaneous transmission on the uplink, and N _dn user terminals are selected. Simultaneous transmission on the downlink, N _up may or may not be equal to N _dn , and N _up and N _dn may be static values or may vary with each scheduling interval. Beam steering or some other spatial processing technique can be used at the access point and user terminal.

On the uplink, at each user terminal 120 selected for uplink transmission, a transmit (TX) data processor 288 receives the traffic data from the data source 286 and the control data from the controller 280. Controller 280 can be coupled to memory 282. TX data processor 288 processes (e.g., encodes, interleaves, and modulates) the traffic data for the user terminal and provides a string of data symbols based on encoding and modulation schemes associated with the rate selected for the user terminal. flow. The TX spatial processor 290 performs spatial processing on the data symbol stream and Antenna Send a stream of symbols. Each transmitter unit (TMTR) 254 receives and processes (e.g., converts to analog, amplifies, filters, and upconverts) respective transmit symbol streams to produce an uplink signal. Transmitter unit 254 provides Uplink signals to proceed from Transmission of antenna 252 to the access point.

N _up user terminals can be scheduled for simultaneous transmission on the uplink. Each of the user terminals performs spatial processing on its data symbol stream and transmits its set of transmitted symbol streams to the access point on the uplink.

At access point 110, The antennas 224a through 224ap receive uplink signals from all N _up user terminals transmitting on the uplink. Each antenna 224 provides a received signal to a respective receiver unit (RCVR) 222. Each receiver unit 222 performs processing complementary to that performed by the transmitter unit 254 and provides a received symbol stream. RX space processor 240 pairs from Receiver unit 222 The received symbol streams perform receiver spatial processing and provide N _up recovered uplink data symbol streams. Receiver spatial processing is performed based on channel correlation matrix inversion (CCMI), minimum mean square error (MMSE), soft interference cancellation (SIC), or some other technique. Each recovered uplink data symbol stream is an estimate of the data symbol stream transmitted by the corresponding user terminal. RX data processor 242 processes (e.g., demodulates, deinterleaves, and decodes) the stream to obtain decoded data based on the rate used for each recovered uplink data symbol stream. The decoded material for each user terminal can be provided to data slot 244 for storage and/or to controller 230 for further processing. Controller 230 can be coupled to memory 232.

On the downlink, at access point 110, TX data processor 210 receives traffic data from data source 208 for N _dn user terminals scheduled for downlink transmission, control from controller 230 The information, as well as other information from the scheduler 234, may also be available. Various types of data can be sent on different transmission channels. TX data processor 210 processes (e.g., encodes, interleaves, and modulates) the traffic data for the user terminal based on the rate selected for each user terminal. The TX data processor 210 provides N _dn downlink data symbol streams for N _dn user terminals. The TX spatial processor 220 performs spatial processing (such as precoding or beamforming, as described in the context of the N _dn downlink data symbol streams) and is Antenna Send a stream of symbols. Each transmitter unit 222 receives and processes a respective transmit symbol stream to generate a downlink signal. Transmitter unit 222 provides Downlink signals to proceed from Transmission of antenna 224 to the user terminal. The decoded material for each user terminal can be provided to data slot 272 for storage and/or to controller 280 for further processing.

At each user terminal 120, Antennas 252 receive from access point 110 Downlink signals. Each receiver unit 254 processes the received signal from the associated antenna 252 and provides the received symbol stream. RX space processor 260 pairs from Receiver unit 254 The received symbol stream performs receiver spatial processing and provides a recovered downlink data symbol stream for the user terminal. Receiver spatial processing is performed in accordance with CCM1, MMSE, or some other technique. The RX data processor 270 processes (e.g., demodulates, deinterleaves, and decodes) the recovered downlink data symbol stream to obtain decoded data for the user terminal.

At each user terminal 120, channel estimator 278 estimates the downlink channel response and provides a downlink channel estimate, which may include channel gain estimates, SNR estimates, noise variances, and the like. Similarly, at access point 110, channel estimator 228 estimates the uplink channel response and provides an uplink channel estimate. The controller 280 of each user terminal typically derives a spatial filtering matrix for the user terminal based on the downlink channel response matrix _Hdn,m of the user terminal. The controller 230 derives the spatial filtering matrix of the access point based on the effective uplink channel response matrix _Hup,eff . The controller 280 of each user terminal can send feedback information (eg, downlink and/or uplink feature vectors, eigenvalues, SNR estimates, etc.) to the access point. Controllers 230 and 280 also control the operation of various processing units at access point 110 and at user terminal 120, respectively.

FIG. 3 illustrates various elements that may be used in wireless device 302 that may be employed within MIMO system 100. Wireless device 302 is an example of a device that can be configured to implement the various methods described herein. For example, the wireless device can implement operations 700 and operations 900 illustrated in Figures 7 and 9, respectively. Wireless device 302 can be access point 110 or user terminal 120.

Wireless device 302 can include a processor 304 that controls the operation of wireless device 302. Processor 304 may also be referred to as a central processing unit (CPU). Memory 306, which may include both read-only memory (ROM) and random access memory (RAM), provides instructions and data to processor 304. A portion of the memory 306 may also include non-volatile random access memory (NVRAM). The processor 304 typically performs logical and arithmetic operations based on program instructions stored in the memory 306. The instructions in memory 306 may be executable to implement the methods described herein.

The wireless device 302 can also include a housing 308 that can include a transmitter 310 and a receiver 312 to allow for transmission and reception of data between the wireless device 302 and a remote node. Transmitter 310 and receiver 312 can be combined into transceiver 314. Single or multiple transmit antennas 316 may be attached to the housing 308 and electrically coupled to the transceiver 314. The wireless device 302 can also include (not shown) a plurality of transmitters, a plurality of receivers, and a plurality of transceivers.

The wireless device 302 can also include a signal detector 318 that can be used to attempt to detect and quantize the level of the signal received by the receiver 314. Signal detector 318 can detect signals such as total energy, energy per carrier per symbol, power spectral density, and other signals. Wireless device 302 can also include a digital signal processor (DSP) 320 for processing signals.

The various components of the wireless device 302 can be coupled together via a busbar system 322, which can include, in addition to the data busbars, a power busbar, a control signal busbar, and a status signal busbar. Sample pitch assignment

As described above, a packet (also referred to as a frame) can be transmitted over a wireless medium using a waveform that is modulated over a fixed frequency band during a fixed period of time. The frequency band can be divided into one or more "tones" and the time period can be divided into one or more "symbols". As an illustrative, non-limiting example, the 20 MHz band can be divided into four 5 MHz tones and the 80 microsecond period can be divided into twenty 4 microsecond symbols. Thus, "tone" can represent the frequency sub-band that is included in the waveform. The tone can alternatively be referred to as a secondary carrier. The "tone" can thus be a frequency domain unit. The "symbol" may be a time domain unit representing the duration of time included in the waveform. Thus, the waveform for the wireless packet can thus be visualized as a two-dimensional structure comprising a plurality of tones (typically on the vertical axis in units of frequency) and a plurality of symbols (on the horizontal axis in units of time) .

For example, a wireless device can receive a packet via a 20 megahertz (MHz) wireless channel (eg, a channel having a 20 MHz bandwidth). The wireless device can perform a 64-point fast Fourier transform (FFT) to determine the 64 tones in the packet's waveform. A subset of the tones can be considered "available" and the remaining tones can be considered "unavailable" (eg, can be protected tones, direct current (DC) tones, etc.). To illustrate, 56 of the 64 tones may be available, including 52 data tones and 4 pilot tones. As another example, there can be 48 data tones and 4 pilot tones. It should be noted that the above channel bandwidth, transform and tone schemes are for the sake of example. According to alternative embodiments, different channel bandwidths (eg, 5 MHz, 6 MHz, 6.5 MHz, 40 MHz, 80 MHz, etc.), different transforms (eg, 256-point FFT, 1024-point FFT, etc.) and/or may be used. Or different pitch plans. Example Phase Tracking in HE-LTF

Aspects of the present disclosure provide, as a whole, techniques that can be used to track the phase and/or carrier frequency offset (CFO) of a wireless packet using extended symbol duration (e.g., 2x and/or 4x symbol duration). This technique can help determine which tones are assigned to transmit pilot signals in LTFs that use extended symbol durations, such as 2x and 4x High Efficiency (HE) LTFs.

In some applications, longer symbol durations are used for various parts of the frame. For example, FIG. 4 illustrates an example packet 400 in which a longer symbol duration (eg, 2x or 4x) is used for the HE-LTF and subsequent data payloads. The symbol duration is longer relative to the reference duration (eg, 1x symbol duration for the legacy preamble portion and/or the HE-SIG field).

As longer symbol durations are used in various applications, phase tracking and carrier frequency offset (CFO) adjustments may be necessary due to differences between the oscillators at the transmitting device and the receiving device. Given that HE-LTF is longer than other symbol durations (eg, LTF defined by 802.11ac) (eg, 2x or 4x long), an increase in the symbol duration of a long training field such as HE-LTF may make expectations Phase tracking and/or CFO adjustments are performed during channel estimation.

When attempting to apply an existing digital scheme (where the term digit scheme typically represents or defines a "tone map" that specifies the number and location of tones used to transmit data/lead frequency signals), certain challenges may arise. For example, according to existing digital schemes, 2x LTF (2x general/reference symbol length) is typically only padded every 4x OFDM symbol (4x normal/reference symbol length). This brings various options for deciding how to perform phase tracking, for example, for transmissions with a single source to be tracked (such as single-user (SU) transmission), DL MU MIMO, and uplink and downlink Road OFDMA transmission (eg, where the transmitter is assigned a separate frequency).

Aspects of the present disclosure provide various techniques for performing phase tracking during channel estimation using LTF. In some cases, phase tracking can be performed via using pilot frequencies transmitted on individual tones in the LTF. In other cases, phase tracking can be performed without using pilot frequencies, but via using orthogonal LTF sequences.

5 illustrates a block diagram of an example operation 500 for wireless communication by a transmitting device that allows (by a receiving device) to perform pilot frequency based phase tracking (by a receiving device), in accordance with certain aspects of the present disclosure.

Operation 500 begins at 502 with generating a frame having one or more fields (LTFs) having therein pilot frequency symbols to be transmitted via one or more tones. At 504, the transmitting device outputs the frame for transmission.

6 illustrates a block diagram of an example operation 600 for wireless communication by a receiving device for performing pilot frequency based phase tracking, in accordance with certain aspects of the present disclosure. For example, operation 600 can be considered a complementary "receiver side" operation for processing frames transmitted in accordance with the operations illustrated in FIG.

Operation 600 begins at 602 by acquiring a frame having one or more fields (LTFs) having pilot symbols transmitted thereon on one or more tones. At 604, the receiving device performs channel estimation for the frame based on the LTF and performs phase tracking based on the pilot frequency symbols.

According to some aspects, for pilot-based phase tracking in LTF, existing pitch plans can be used to determine which positions/or quantities of tones are to be used to transmit pilot frequencies. For example, for a 4x LTF, the same tone plan can be used to send a single stream pilot (SSP or SSP pilot symbol) in the data portion of the packet. In this case, the same number of pilot and pilot tone positions can be used in the LTF as used in the data.

However, as mentioned above, there may be different considerations for 2x LTF, for example, this is because the 2x LTF may be via a tone only in every 4x OFDM symbol (and in existing 4x data symbols, pilot tone) Can be generated by padding with an odd index. However, aspects of the present disclosure can provide a pilot frequency design in a 2x LTF that utilizes (eg, a single stream) the number and location of pilot frequencies, which allows for acceptable tracking performance.

Various methods are provided for adapting 2x LTFs where the pilot frequency position is not aligned during the data portion of the packet and during LTF. For example, according to one approach, a 2x digital scheme can be used in the LTF for pilot frequencies. In another approach, the same number of pilot frequencies can be used as in the 4x LTF digital scheme.

Using a 2x digital scheme in the 2x LTF for piloting may result in more than half of the pilot tone tones in 4x, which represents an increase in pilot frequency density relative to the 4x digital scheme. Therefore, it is expected that this method has a phase tracking performance that is not worse than 4x LTF. In this case, it may not be necessary to further reduce the number of pilot frequencies, which avoids the need for a new pilot tone tone plan. In some cases, the number of pilot tones and the pilot frequency position in the 2x LTF may follow one of the following 2x digit schemes: − 80 MHz: 16 pilot frequencies in the 512 FFT and their locations (HE40) − 40 MHz: 8 pilot frequencies and their positions in the 256 FFT (HE20) − 20MHz: 6 pilot frequencies and their positions in the 128 FFT (VHT40) − 106-tone RU (resource unit): as in 52-tone 4 pilot frequencies in RU and their positions − 52-tone RU: 2 pilot frequencies as in 26-tone RU and their position − 26-tone RU: new pitch plan for 13 pitch blocks for new (13-tone) tone block, in some cases a single (1) pilot tone tone can be used at the center of the (13-tone block), considering that the channel should normally be relatively flat on the block (and the same The pilot frequency power can be used as two pilot frequencies in a 26-tone RU. In other cases, multiple pilot tone tones (eg, 2 pilot tone tones in the 5th and 9th tones in the 13 tone block) may be used instead of a single tone in the middle to provide better diversity gain and Power gain.

In some cases, when using a 2x digital scheme for piloting frequencies in a 2x LTF, in order to minimize the extrapolation loss for channel estimation for 4x data, several padded (available) 2x LTFs are (closer) The edge or both edges are expanded. This example digital scheme can be referred to as an "extended" 2x digital scheme.

In some cases, all other RUs may use an existing digital scheme in addition to the new 13 tone block for the 2x LTF of the 26-tone RU, which has been defined (eg, for 802.11ac/11ah). In this application, the pilot frequency is used for phase tracking between 2x LTF and 2x LTF rather than between 2x and 4x, so phase tracking may not have additional complexity. Although the pilot position may not be aligned during data and LTF, such alignment may not be necessary because the phase offset in the data symbols can be estimated with respect to the estimated channel rather than the pilot frequency in the LTF, and Channel interpolation is usually required when sending 2x LTFs.

As mentioned above, in some cases, the same number of pilot frequencies can be used in a 2x LTF as in a 4x LTF. In the current 4x digital scheme, the pilot tone has an odd index. Therefore, in order to have the same number of pilot frequencies in the 2x LTF as in 4x, the pilot frequency positions can be shifted to the even tone index in the 4x LTF, so they can all be padded in the 2x LTF. As mentioned above, it may not be necessary to further shift the pilot frequency position during the data to align all of the pilot frequency indices in the LTF and data, but may illustrate maintaining the consistency of the pilot frequencies for both LTF and data. . Using the same number of pilot frequencies in a 2x LTF as in a 4x LTF can result in a new pilot plan for 2x and 4x digital schemes. The more pilot frequencies in the LTF can result in more channel interpolation required for the tone of the data around the pilot tone positions.

In some cases, the number of pilot tone tones in a 2x LTF can be the same as in a 4x digit scheme. In such cases, the pilot position in the 2x LTF and 4x data (if needed) can follow (existing 4x pilot tone index +1) or (existing 4x pilot tone index-1), where 2x LTF The exact pilot position in is equal to the modified 4x pilot index divided by 2, such as: − 2x LTF for 80MHz: 16 pilot frequencies and their position is (lead tone pitch index +/- 1 in 1024 FFT) /2 − 2x LTF for 40MHz: 16 pilot frequencies and their positions are (lead tone pitch index +/-1 in 512 FFT)/2 − 2x LTF for 20MHz: 8 pilot frequencies and their positions are (Pilot frequency tone index in 256 FFT +/- 1)/2 − 2x LTF for 106-tone RU: 4 pilot frequencies and their position is (pilot frequency tone index +/- 1 in 106-tone RU 2/2 LTF for 52-tone RU: 4 pilot frequencies and their positions are (lead tone pitch index +/- 1 in 52-tone RU)/2 − 2x LTF for 26-tone RU : 2 pilot frequencies and their positions are (lead tone tone index +/- 1 in 26-tone RU)/2

7 illustrates a block diagram of an example operation 700 for wireless communication by a transmitting device that allows non-guided frequency based phase tracking using LTF, in accordance with certain aspects of the present disclosure.

Operation 700 begins at 702: generating a frame having a plurality of orthogonal long training field (LTF) sequences, each orthogonal LTF sequence being assigned to a different spatial stream to allow for LTF based during channel estimation For phase tracking. At 704, the transmitting device outputs the frame for single-user (SU) transmission, downlink multi-user (MU) multiple-input multiple-output (MIMO) transmission, or orthogonal frequency division multiplexing access (OFDMA) transmission. Transfer.

8 illustrates a block diagram of an example operation 800 for wireless communication by a receiving device for performing non-guided frequency based phase tracking, in accordance with certain aspects of the present disclosure. For example, operation 800 can be considered a complementary "receiver side" operation for processing frames transmitted in accordance with the operations illustrated in FIG.

Operation 800 can begin at 802: acquire a frame having a plurality of orthogonal long training field (LTF) sequences, each orthogonal LTF sequence being assigned to a different spatial stream, the frame being a single user (SU) transmission, downlink multi-user (MU) multiple-input multiple-output (MIMO) transmission, or orthogonal frequency division multiplexing access (OFDMA) transmission is obtained. At 804, the receiving device performs at least one of channel estimation or phase tracking for the frame based on the LTF.

When orthogonal orthogonal LTF sequences are used across streams, different LTF sequences can be assigned to different streams. In this case, all data tones and at least "first + last" LTF symbols can be used to estimate the carrier frequency offset (CFO). This approach may be advantageous because no pilot frequency is required in the LTF and may result in a larger cumulative gain from a greater number of LTF tones than the pilot tone in the LTF. Orthogonal LTF sequences can also be applied to both 2x and 4x LTFs.

In some cases, Nss orthogonal LTF sequences can be used for Nss streams (1-to-1 mapping). This approach can result in a full merge gain, but may also require at least Nss adjacent tones to have the same channel. In other cases, fewer than Nss orthogonal LTF sequences can be used. For example, only two orthogonal LTF sequences can be used: one for the first stream and one for the remainder of the streams (eg, the remaining Nss - 1 stream). This approach can reduce the need for flat channels to only two adjacent tones, but can also result in multiple streams (eg, when >2 streams for a user) The estimated phase drift is averaged for loss, and sometimes, due to sticking to only one stream for tracking, power loss can result.

In some scenarios, for phase tracking purposes, a single stream pilot frequency may provide better performance than a quadrature LTF, for example, for MIMO transmission in a frequency selective channel at medium to high SNR. In such cases, the channel loss around the pilot frequency may be higher than other tones from the perspective of channel interpolation, but may not have a significant impact due to the limited pilot frequency.

However, in such cases, when beamforming is performed, certain techniques may be employed to perform channel interpolation at the pilot frequency. Such techniques may be used when generating a precoding matrix (which is used for beamforming transmission) based on feedback from devices that receive pilot frequencies. In some cases, to smooth the precoded channels, precoding matrix entries corresponding to particular pilot tone tones may be generated based on feedback for the channels transmitted on other tones. For example, a precoding matrix for pilot tone tones with pitch index n can be generated based on interpolated channel feedback on two adjacent tones (with tone indices n-1 and n+1 ): W(H(H( n )) = f(H( n-1 ), H( n+1 ))

In some cases, it may be considered how to place pilot tone tones in a given resource unit (RU) so that it can be used for 2x LTFs. One method is to place pilot frequencies in all RUs at even tones. This may actually imply the use of two pilot frequency structures that are mirror symmetric, which may not result in a consistent design and may still need to know the RU position to determine the pilot frequency structure. In general, a pilot frequency structure may be difficult or impossible to achieve a goal that has an even tone index for all pilot frequencies. In some cases, both spectral lines and RU locations may have mirror symmetry.

In some cases, as mentioned above, the pilot tone tone position may be based on a relative pilot frequency structure within each RU. In this case, a separate pilot frequency structure can be used for LTF and data (eg, via reuse for legacy digital schemes for 2x and 4x) such that the 2x LTF uses 2x pilot frequencies, while the 4x LTF and data uses 4x pilot frequencies.

Another solution is to use a fixed absolute pilot structure for the entire PPDU. In this case, it may be based on a defined set of pilot frequencies in a fixed tone position in a given PPDU bandwidth (eg, 20/40/80 MHz) to be used for any resource configuration scheme (eg, all in even tones) The index is used to select (for example, the device can select) the pilot tone position. For each assignment, the pilot tone tones within the assigned RU can be selected based on the defined set, with appropriate puncturing to accommodate the RU size.

For a specific, but non-limiting example, 18 pilot frequencies at a fixed location can be defined in a 20 MHz PPDU to accommodate up to nine user assignments, with each user allocation having 2 pilot frequencies in a 26-RU. . Assuming that one STA is assigned 106 RU, there will be 8 pilot frequencies within the 106 RU. In order to obtain 4 pilot frequencies from the 8 pilot frequencies for 106 RU, puncturing may be performed at every other pilot frequency (e.g., according to any suitable puncturing rules/by applying any suitable puncturing rules).

One advantage of a fixed absolute pilot frequency structure for the entire PPDU is that the pilot frequency locations can be aligned in any RU or any distribution, which can aid in hardware design. In addition, having pilot bit positions that are independent of RU design and resource configuration can make OFDMA processing simpler. For example, if all of the pilot frequencies defined are at even tones, the 2x and 4x transmissions will use the same set of pilot frequencies for LTF, which makes LTF processing simpler. Having a fixed absolute pilot frequency structure can be beneficial for downlink shared pilot frequency usage.

Figure 9 illustrates an example of a fixed absolute pilot frequency structure. The illustrated example proposes 18 pilot frequencies in 20 MHz, 36 pilot frequencies in 40 MHz, and 74 pilot frequencies in 80 MHz. In the illustrated example, all pilot frequencies are placed at even tones and evenly spread across the entire spectral line of the PPDU.

In the illustrated example, the proposed pilot tone tone index for 20 MHz is: ±10, ±22, ±36, ±48, ±62, ±76, ±90, ±102, ±116. For 40 MHz, the proposed pitch index is: ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158, ±170, ± 184, ± 198, ± 212, ± 224, ± 238. For 80 MHz, the proposed pitch index is: ±10, ±24, ±38, ±50, ±64, ±78, ±92, ±104, ±118, ±130, ±144, ±158, ±172, ± 184, ±198, ±212, ±226, ±238, ±252, ±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414, ±426, ±440, ±454, ±468, ±480, ±494.

Figures 10-12 illustrate an exemplary plot of the absolute pitch structure of Figure 9 in accordance with aspects of the present disclosure. Figure 10 illustrates an example tone map of 18 pilot frequencies in 20 MHz, Figure 11 illustrates an example tone map of 36 pilot frequencies in 40 MHz, and Figure 12 illustrates example tone of 74 pilot frequencies in 80 MHz map.

Figure 14 illustrates another example absolute pitch structure (an alternate structure of the structure illustrated in Figure 9) in accordance with aspects of the present disclosure. In the illustrated example, the proposed pilot tone tone index for 20 MHz is the same as that illustrated in FIG. For 40 MHz, the proposed pitch index is: ±8, ±22, ±34, ±48, ±62, ±76, ±88, ±102, ±116, ±130, ±144, ±158, ±170, ± 184, ± 198, ± 212, ± 224, ± 238. For 80 MHz, the proposed pitch index is: ±10, ±22, ±36, ±48, ±62, ±76, ±90, ±102, ±116, ±130, ±144, ±158, ±172, ± 184, ±198, ±212, ±226, ±238, ±252, ±264, ±278, ±290, ±304, ±318, ±332, ±344, ±358, ±372, ±386, ±400, ±414, ±426, ±440, ±454, ±468, ±480, ±494.

Similar to Figures 10-12, Figures 15-17 illustrate an exemplary plot of the absolute pitch structure of Figure 14 in accordance with aspects of the present disclosure. The plots illustrated in Figures 10-12 and 15-17 illustrate how certain remaining tones (yellow blocks) and RU positions are given, and how the defined pilot frequencies are in each of the RUs of the example RU. Use and punch. The remaining tones can also be referred to as "empty tones" because they can have no energy.

In general, for 26 and 52 tone RUs, all available pilot frequencies in each RU can be used. For 106 (i.e., 102+4) and 242 tone RUs, half of the available pilot tone tones can be punctured. As illustrated in Figure 18, in some cases, the relative pilot frequency position may be kept relatively close to the symmetric pilot frequency structure defined in 11ah (having an even pilot index and an odd pilot index). Regardless of the remaining pitch allocation plan, there may be three variations of the pilot tone pitch position within the 26 tone RU, as illustrated in FIG. In the first variant, the 26-tone RU may have the leftmost pitch starting from the even index and the structure of [6P13P5] may be used. In the second variant, the leftmost pitch can start from an odd index and may require a structure of [5P13P6]. In a third variation, the center 26 tone RU pilot frequency structure may be [6P6 6P6].

In order to ensure that all pilot frequencies have an even tone index, the relative pilot frequency locations within the 26 tone RUs must be changed for different 26 tone RUs.

For example, referring to Figure 10, for 20 MHz, a pair of pilot tone tone indices (indicated by arrows) can be selected for each 26 tone RU (from left to right, -116/-102, -90/-76, -62/-48, -36/-22, -10/10, 22/36, 48/62, 76/90 and 102/116). Similarly, a set of four pilot tone tone indices in the same pilot tone tone index can be used for 52 tone RUs (-116/-102/-90/-76, -62/-48/-36/- 22, 22/36/48/62 and 76/90/102/116). On the other hand, only half of the pitch indices in the pitch indices can be selected for 106 tone RUs (-116/-90/-48/-22 and 22/48/90/116) and 242 tone RUs (- 116/-90/-48/-22/22/48/90/116), while other pilot tone pitch indexes are punctured (from left to right, -102, -76, -62, -36, -10, 10, 36, 62, 76 and 102).

Similarly, referring to Figure 11, for 40 MHz, pairs of pilot tone tone indices (indicated by arrows) can be selected for each 26 tone RU (from left to right, -238/-224, -212/-198) , -184/-170, -158/-144, -130/-116, -104/-90, -78/-64, -50/-36, -24/-10, 10/24, 36/50 , 64/78, 90/104, 116/130, 144/158, 170/184, 198/212 and 224/238). Similarly, a set of four pilot tone tone indices in the same pilot tone tone index can be used for 52 tone RUs (-238/-224/-212/-198, -184/-170/-158/- 144, -104/-90/-78/-64, -50/-36/-24/-10, 10/24/36/50, 64/78/90/104, 144/158/170/184 and 198/212/224/238). On the other hand, less than half of the pitch indices in the pitch indices can be selected for 106 tone RUs (-238/-212/-170/-144, -104/-78/-36/-10, 10 /36/78/104 and 144/170/212/238) and 242 tone RU (-238/-212/-170/-144/-104/-78/-36/-10 and 10/36/78/ 104/144/170/212/238), while other pilot tone pitch indexes are punctured.

Similarly, referring to Figure 12, for 80 MHz, pairs of pilot tone tone indices (indicated by arrows) can be selected for each 26 tone RU (from left to right, -494/-480, -468/-454) , -440/-426, -414/-400, -386/-372, -360/-346, -334/-320, -306/-292, -280/-266, -252/-238, - 226/-212, -198/-184, -172/-158, -144/-130, -118/-104, -92/-78, -64/-50, -38/-24, -10/ 10, 24/38, 50/64, 78/92, 104/118, 130/144, 158/172, 184/198, 212/226, 238/252, 266/280, 292/306, 320/334, 346/360, 372/386, 400/414, 426/440, 454/468 and 480/494). Similarly, a set of four pilot frequency indices in the same pilot index can be used for 52 tone RUs (from left to right, -494/-480/-468/-454, -440/-426/- 414/-400, -360/-346/-334/-320, -306/-292/-280/-266, -252/-238/-226/-212, -198/-184/-172/ -158, -118/-104/-92/-78, -64/-50/-38/-24, 24/38/50/64, 78/92/104/118, 158/172/184/198 , 212/226/238/252, 266/280/292/306, 320/334/346/360, 400/414/426/440 and 454/468/480/494). On the other hand, only half or less of the pitch indices in the pitch indices can be selected for 106 tone RUs (-494/-468/-426/-400, -360/-334/-292/- 266, -252/-226/-184/-158, -118/-92/-50/-24, 24/50/92/118, 158/184/226/252, 266/292/334/360 and 400/426/468/494) and 242 tone RU (-494/-468/-426/-400/-360/-334/-292/-266, -252/-226/-184/-158/- 118/-92/-50/-24, 24/50/92/118/158/184/226/252 and 266/292/334/360/400/426/468/494), while other pilot tone tones index Being punched. On the other hand, only a quarter or less of the pitch indices in the pitch indices can be selected for the 996 tone RU (-468/-400/-334/-266/-226/-158/- 92/-24, 24/92/158/226/266/334/400/468), while other pilot tone pitch indexes are punctured.

The table illustrated in Figure 13 summarizes the pilot tone pitch indices for the different combinations of channel bandwidth and RU size illustrated in Figures 10-12. In other words, depending on the channel bandwidth and RU size, an appropriate number of pilot tone pitch indices can be selected from the values illustrated in the table (eg, a pair of pitch indices in the pitch index indicated for the 26-tone RU) , or 4 pitch indices in the pitch index indicated for the 52 tone RU).

Referring to FIG. 15, for the 20 MHz tone map illustrated in FIG. 14, the pilot tone pitch index selected for the different RUs may be the same as that illustrated in FIG.

Similarly, referring to Figure 16, for the 40 MHz tone map illustrated in Figure 14, a pair of pilot tone tone indices (indicated by arrows) can be selected for each 26 tone RU (from left to right, -238/) -224, -212/-198, -184/-170, -158/-144, -130/-116, -102/-88, -76/-62, -48/-34, -22/-8 , 8/22, 34/48, 62/76, 88/102, 116/130, 144/158, 170/184, 198/212 and 224/238). Similarly, a set of four pilot tone tone indices in the same pilot tone tone index can be used for 52 tone RUs (-238/-224/-212/-198, -184/-170/-158/- 144, -102/-88/-76/-62, -48/-34/-22/-8, 8/22/34/48, 62/76/88/102, 144/158/170/184 and 198/212/224/238). On the other hand, less than half of the pitch indices in the pitch indices can be selected for 106 tone RUs (-238/-212/-170/-144, -102/-76/-34/-8, 8 /34/76/102 and 144/170/212/238) and 242 tone RU (-238/-212/-170/-144/-102/-76/-34/-8 and 8/34/76/ 102/144/170/212/238), while other pilot tone pitch indexes are punctured.

Similarly, referring to Figure 17, for 80 MHz, a pair of pilot tone tone indices (indicated by arrows) can be selected for each 26 tone RU (from left to right, -494/-480, -468/-454) , -440/-426, -414/-400, -386/-372, -358/-344, -332/-318, -304/-290, -278/-264, -252/-238, - 226/-212, -198/-184, -172/-158, -144/-130, -116/-102, -90/-76, -62/-48, -36/-22, -10/ 10, 22/36, 48/62, 76/90, 102/116, 130/144, 158/172, 184/198, 212/226, 238/252, 264/278, 290/304, 318/332, 344/358, 372/386, 400/414, 426/440, 454/468 and 480/494). Similarly, a set of four pilot tone tone indices in the same pilot tone tone index can be used for 52 tone RUs (from left to right, -494/-480/-468/-454, -440/-426) /-414/-400, -358/-344/-332/-318, -304/-290/-278/-264, -252/-238/-226/-212, -198/-184/- 172/-158, -116/-102/-90/-76, -62/-48/-36/-22, 22/36/48/62, 76/90/102/116, 158/172/184 / 198, 212/226/238/252, 264/278/290/304, 318/332/344/358, 400/414/426/440 and 454/468/480/494). On the other hand, only half or less of the pitch indices in the pitch indices can be selected for 106 tone RUs (-494/-468/-426/-400, -358/-332/-290/- 264, -252/-226/-184/-158, -116/-90/-48/-22, 22/48/90/116, 158/184/226/252, 264/290/332/358 and 400/426/468/494) and 242 tone RU (-494/-468/-426/-400/-358/-332/-290/-264, 252/-226/-184/-158/-116 /-90/-48/-22, 22/48/90/116/158/184/226/252 and 264/290/332/358/400/426/468/494), while other pilot tone tones were Punch. On the other hand, only a quarter or less of the pitch indices in the pitch indices can be selected for the 996 tone RU (-468/-400/-332/-264/-226/-158/- 90/-22, 22/90/158/226/264/332/400/468), while other pilot tone pitch indexes are punctured.

As illustrated in these examples, in many cases, the pilot frequency of a 52-tone RU can be aligned with the pilot frequency in a corresponding 2x26 tone RU. Moreover, as illustrated in the examples, an index of a larger RU may be selected from a pilot index of a smaller RU (eg, a 106 tone RU pilot frequency may be from a pilot index of a corresponding 2x52 tone RU) Selected) as illustrated in FIG.

In the illustrated example, puncturing is performed in a mirror symmetrical manner, such as within 242 tones, to spread more evenly within the 996 tone RU in 80 MHz. For a 996 tone RU, every other pilot frequency can be inherited from 242 RU for good alignment between the RUs. In the illustrated example, the same puncturing rule is applied for 20/40/80 MHz. Of course, this is merely an example, and various different puncturing rules can be applied in the pilot frequency selection in each RU.

Exactly how much pilot frequency is necessary can be based on various factors. For example, given 4 pilot frequencies in 11ac20 to achieve frequency error accuracy A , A/2 accuracy should be sufficient in the case of 2x LTF, while 11ax 2x LTF with 4 pilot frequencies persists due to 2x symbols The time thus can be obtained as B=A/2, and the 11ax 2x LTF with 8 pilot frequencies can obtain C=B/sqrt(2) due to the double number of pilot frequencies.

The methods described herein include one or more steps or actions for implementing the methods described. The method steps and/or actions may be interchanged with one another without departing from the scope of the invention. In other words, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

As used herein, a phrase referring to at least one of the item list "represents any combination of the items, including a single member." For example, "at least one of: a, b, or c" is intended to encompass a, b, c, ab, ac, bc, and abc, and any combination of multiples of the same element (eg, aa, aaa, aab, Aac, abb, acc, bb, bbb, bbc, cc, and ccc or any other ordering of a, b, and c).

As used herein, the term "decision" includes a wide variety of actions. For example, "decision" can include calculations, operations, processing, derivation, research, inspection (eg, viewing in a table, database, or other data structure), assertion, and the like. In addition, "decision" may include receiving (eg, receiving information), accessing (eg, accessing data in memory), and the like. In addition, "decision" can include parsing, selecting, selecting, establishing, and the like.

In some cases, the device may have an interface for outputting frames for transmission, rather than actually transmitting frames. For example, the processor can output a frame to the RF front end for transmission via the bus. Similarly, a device may have an interface for acquiring frames received from another device instead of actually receiving a frame. For example, the processor can acquire (or receive) a frame from the RF front end for transmission via the bus interface.

The various operations described above can be performed by any suitable means capable of performing the corresponding functions. Such components may include various hardware and/or software components and/or modules including, but not limited to, circuits, special application integrated circuits (ASICs), or processors. In general, where there are operations illustrated in the figures, the operations may have component-plus-function elements with corresponding corresponding numbers. For example, the operations 500, 600, 700, and 800 illustrated in Figures 5, 6, 7, and 8 correspond to the components 500A, 600A, 700A illustrated in Figures 5A, 6A, 7A, and 6A, respectively. 800A.

For example, the means for receiving and the means for acquiring may be the receiver of the user terminal 120 illustrated in FIG. 2 (eg, the receiver unit of the transceiver 254) and/or the antenna 252 or illustrated in FIG. The receiver of access point 110 (e.g., the receiver unit of transceiver 222) and/or antenna 224. The means for transmitting and the means for outputting may be the transmitter of the user terminal 120 (eg, the transmitter unit of the transceiver 254) illustrated in FIG. 2 and/or the antenna 252 or the memory illustrated in FIG. A transmitter of point 110 (e.g., a transmitter unit of transceiver 222) and/or antenna 224 is taken.

The means for generating, the means for determining, the means for selecting, the means for performing channel estimation, and/or the means for performing phase tracking may comprise a processing system, which may include one or more processes The RX data processor 270, the TX data processor 288 and/or the controller 280 of the user terminal 120 illustrated in FIG. 2 or the TX data processor 210, RX of the access point 110 illustrated in FIG. Data processor 242 and/or controller 230.

The various illustrative logic blocks, modules, and circuits described in connection with the disclosure herein may utilize a general purpose processor, digital signal processor (DSP), special application integrated circuit (ASIC) designed to perform the functions described herein. ), Field Programmable Gate Array (FPGA) or other programmable logic device (PLD), individual gate or transistor logic, individual hardware components, or any combination thereof, implemented or executed. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller or state machine. The processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

If implemented in hardware, the example hardware settings can include processing systems in the wireless node. The processing system can be implemented using a busbar architecture. The bus bar can include any number of interconnect bus bars and bridges depending on the particular application of the processing system and overall design constraints. The bus can connect various circuits including the processor, machine readable media, and bus interface. The bus interface can be used to connect the network interface card to the processing system via the bus bar. The network interface card can be used to implement the signal processing function of the PHY layer. In the case of the user terminal 120 (see FIG. 1), a user interface (eg, a keyboard, display, mouse, joystick, etc.) can also be connected to the busbar. The busbars can also be connected to various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are well known in the art and will therefore not be further described. The processor can be implemented using one or more general purpose and/or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how best to implement the described functionality of the processing system, depending on the particular application and the overall design constraints imposed on the overall system.

If implemented in software, the functions may be stored on or transmitted over the computing readable medium as one or more instructions or codes. Whether referred to as software, firmware, mediation software, microcode, hardware description language, or other terms, software should be interpreted broadly to mean instructions, materials, or any combination thereof. Computer readable media includes both computer storage media and communication media, including any media that facilitates the transfer of computer programs from one place to another. The processor can be responsible for managing the bus and general processing, including executing software modules stored on a machine readable storage medium. The computer readable storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integrated into the processor. For example, the machine readable medium can include a transmission line, a carrier modulated by the data, and/or a computer readable storage medium having instructions stored thereon separate from the wireless node, all of which can be interfaced by the processor via the bus interface Come to access. Alternatively or in addition, the machine readable medium or any portion thereof may be integrated into the processor, for example in the case of having a cache memory and/or a generic scratchpad stack. Examples of machine readable storage media may include, for example, RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM ( Erasing programmable read-only memory), EEPROM (electronic erasable programmable read-only memory), scratchpad, diskette, optical disk, hard drive, or any other suitable storage medium, or any combination thereof . Machine readable media can be embodied in computer program products.

The software module can include a single instruction or many instructions, and can be distributed over several different code segments, distributed among different programs and distributed across multiple storage media. Computer readable media can include multiple software modules. The software module includes instructions that, when executed by a device, such as a processor, cause the processing system to perform various functions. The software module can include a transmitting module and a receiving module. Each software module can be resident in a single storage device or distributed across multiple storage devices. For example, when a trigger event occurs, the software module can be loaded from the hard drive into RAM. During execution of the software module, the processor can load some of the instructions into the cache to increase the access speed. One or more cache lines can then be loaded into the general register heap for execution by the processor. When referring to the functionality of the software module below, it will be understood that such functionality is implemented by the processor when executing instructions from the software module.

In addition, any connection is properly referred to as computer readable media. For example, if you use a coaxial cable, fiber optic cable, twisted pair cable, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio, and microwave) to transmit software from a website, server, or other remote source, then coaxial Cables, fiber optic cables, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the media. As used herein, disks and discs include compact discs (CDs), laser discs, compact discs, digital versatile discs (DVDs), floppy discs, and Blu-ray® discs, where the discs are usually magnetically replicated. Information, while CDs use lasers to optically replicate data. Thus, in some aspects, the computer readable medium can include non-transitory computer readable media (eg, tangible media). Moreover, for other aspects, the computer readable medium can include temporary computer readable media (eg, signals). Combinations of the above should also be included within the scope of computer readable media.

Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product can include a computer readable medium having instructions stored thereon (and/or encoded), the instructions being executable by one or more processors to perform the operations described herein. For example, an instruction for determining a time period during which at least one second device is scheduled to wake up, for generating an instruction for transmitting a first frame to the second device during the time period for outputting the first frame And transmitting, by the instruction, the instruction for responding to the second frame of the first frame, for determining the ranging information based on a time difference between the sending of the first frame and the receiving of the second frame And an instruction for generating a third frame including ranging information, and an instruction for outputting the third frame for transmission. In another example, an instruction for determining a time period to wake from a low power state, an instruction to acquire a first frame from the second device during the time period, for generating a response in response to the first frame An instruction transmitted to the second frame of the second device for outputting the second frame for transmission to the second device for acquiring the ranging information (which is transmitted by the second device based on the first frame) An instruction of a third frame determined by a time difference between receipt of the second frame and an instruction for determining a relative position of the second device to the first device based on the third frame.

In addition, it should be appreciated that modules and/or other suitable components for performing the methods and techniques described herein can be downloaded and/or otherwise obtained via a user terminal and/or a base station as desired. For example, such a device can be coupled to a server to facilitate implementing the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage unit (eg, RAM, ROM, physical storage media such as a compact disc (CD) or floppy disk, etc.) such that the user terminal and/or base station are Various methods can be obtained when the storage unit is coupled to or provided to the device. In addition, any other suitable technique for providing the methods and techniques described herein to a device can also be used.

It should be understood that the scope of patent application is not limited to the precise arrangements and elements illustrated in the above. Various modifications, changes and variations can be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the invention.

100‧‧‧ system
110‧‧‧Access Point (AP)
120a‧‧‧user terminal
120b‧‧‧user terminal
120c‧‧‧user terminal
120d‧‧‧user terminal
120e‧‧‧user terminal
120f‧‧‧user terminal
120g‧‧‧user terminal
120h‧‧‧user terminal
120i‧‧‧user terminal
120m‧‧‧user terminal
120x‧‧‧user terminal
130‧‧‧System Controller
208‧‧‧Source
210‧‧‧TX data processor
220‧‧‧TX space processor
222a‧‧‧transmitter unit/receiver unit/transceiver
222ap‧‧‧transmitter unit/receiver unit/transceiver
224a‧‧‧Antenna
224ap‧‧‧Antenna
228‧‧‧channel estimator
230‧‧‧ Controller
232‧‧‧ memory
234‧‧‧ Scheduler
240‧‧‧RX Space Processor
242‧‧‧RX data processor
244‧‧‧ data slot
252ma‧‧‧Antenna
252mu‧‧‧Antenna
252xa‧‧‧Antenna
252xu‧‧‧Antenna
254m‧‧‧transmitter unit/receiver unit/transceiver
254mu‧‧‧transmitter unit/receiver unit/transceiver
254xa‧‧‧transmitter unit/receiver unit/transceiver
254xu‧‧‧transmitter unit/receiver unit/transceiver
260m‧‧‧RX space processor
260x‧‧‧RX Space Processor
270m‧‧‧RX data processor
270x‧‧‧RX data processor
272m‧‧‧ data slot
272x‧‧‧ data slot
278m‧‧‧channel estimator
278x‧‧‧channel estimator
280m‧‧‧ controller
280x‧‧ ‧ controller
282m‧‧‧ memory
282x‧‧‧ memory
286m‧‧‧Source
286x‧‧‧Source
288m‧‧‧TX data processor
288x‧‧‧TX data processor
290m‧‧‧TX space processor
290x‧‧‧TX space processor
302‧‧‧Wireless equipment
304‧‧‧ processor
306‧‧‧ memory
308‧‧‧Shell
310‧‧‧transmitter
312‧‧‧ Receiver
314‧‧‧ transceiver
316‧‧‧ transmit antenna
318‧‧‧Signal Detector
320‧‧‧Digital Signal Processor (DSP)
322‧‧‧ busbar system
400‧‧‧Package
500‧‧‧ operation
500A‧‧‧ components
502‧‧‧ square
502A‧‧‧ square
504‧‧‧
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1 illustrates a diagram of an example wireless communication network in accordance with certain aspects of the present disclosure.

2 illustrates a block diagram of an example access point and a user terminal, in accordance with certain aspects of the present disclosure.

3 illustrates a block diagram of an example wireless device in accordance with certain aspects of the present disclosure.

4 illustrates an example frame structure with a long training field (LTF), in accordance with certain aspects of the present disclosure.

5 illustrates a block diagram of an example operation for wireless communication by a transmitting device, in accordance with certain aspects of the present disclosure.

FIG. 5A illustrates example components capable of performing the operations illustrated in FIG. 5.

6 illustrates a block diagram of an example operation for wireless communication by a receiving device, in accordance with certain aspects of the present disclosure.

FIG. 6A illustrates example components capable of performing the operations illustrated in FIG. 6.

7 illustrates a block diagram of an example operation for wireless communication by a transmitting device, in accordance with certain aspects of the present disclosure.

FIG. 7A illustrates example components capable of performing the operations illustrated in FIG. 7.

8 illustrates a block diagram of an example operation for wireless communication by a receiving device, in accordance with certain aspects of the present disclosure.

FIG. 8A illustrates example components capable of performing the operations illustrated in FIG. 8.

Figure 9 illustrates an example absolute pitch structure in accordance with aspects of the present disclosure.

Figures 10-12 illustrate an exemplary plot of the absolute pitch structure of Figure 9 in accordance with aspects of the present disclosure.

Figure 13 illustrates a table summarizing the pilot tone pitch indices for different combinations of channel bandwidth and RU size illustrated in Figures 10-12.

Figure 14 illustrates an example absolute pitch structure in accordance with aspects of the present disclosure.

15-17 illustrate an exemplary plot of the absolute pitch structure of FIG. 9 in accordance with aspects of the present disclosure.

18-20 illustrate example pitch index locations within a resource unit, in accordance with aspects of the present disclosure.

To facilitate understanding, the same element symbols (as far as possible) have been used to identify the same elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized in other embodiments without particular recitation.

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Claims (28)

An apparatus for wireless communication, comprising: a processing system configured to generate a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream And an interface configured to output the frame for single-user (SU) transmission, one multi-user (MU) multiple-input multiple-output (MIMO) transmission, or one orthogonal frequency division multiplexing access ( OFDMA) transmission for transmission. The apparatus of claim 1, wherein: the frame is output for transmission via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The device of claim 1, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The device of claim 3, wherein the orthogonal training field sequence comprises: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence of a remainder of the Nss spatial streams. An apparatus for wireless communication, comprising: an interface configured to acquire a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream, The frame is obtained by a single user (SU) transmission, a multi-user (MU) multiple-input multiple-output (MIMO) transmission, or an orthogonal frequency division multiplexing access (OFDMA) transmission; and a processing A system configured to perform at least one of channel estimation or phase tracking based on the sequence of training fields. The device of claim 5, wherein: the frame is obtained via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The device of claim 5, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The apparatus of claim 7, wherein the orthogonal training field sequence comprises: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence of a remainder of the Nss spatial streams. A method for wireless communication, comprising the steps of: generating a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream; and outputting the frame For transmission as a single user (SU) transmission, a multi-user (MU) multiple input multiple output (MIMO) transmission, or an orthogonal frequency division multiplexing access (OFDMA) transmission. The method of claim 9, wherein: the frame is output for transmission via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The method of claim 9, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The method of claim 11, wherein the orthogonal training field sequence comprises the following steps: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence for a remainder of the Nss spatial streams. A method for wireless communication, comprising the steps of: acquiring a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream, the frame being Obtained by a single user (SU) transmission, a multi-user (MU) multiple-input multiple-output (MIMO) transmission, or an orthogonal frequency division multiplexing access (OFDMA) transmission; and based on the training field sequences At least one of channel estimation or phase tracking is performed. The method of claim 13, wherein: the frame is obtained via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The method of claim 13, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The method of claim 15, wherein the orthogonal training field sequence comprises the following steps: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence for a remainder of the Nss spatial streams. An apparatus for wireless communication, comprising: means for generating a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream; The frame is output for transmission as a single user (SU) transmission, a multi-user (MU) multiple input multiple output (MIMO) transmission, or an orthogonal frequency division multiple access (OFDMA) transmission. The apparatus of claim 17, wherein: the frame is output for transmission via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The device of claim 17, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The apparatus of claim 19, wherein the orthogonal training field sequence comprises: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence of a remainder of the Nss spatial streams. An apparatus for wireless communication, comprising: means for acquiring a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream, the frame Obtained via a single user (SU) transmission, a multi-user (MU) multiple-input multiple-output (MIMO) transmission, or an orthogonal frequency division multiple access (OFDMA) transmission; and based on such The sequence of fields is trained to perform the construction of at least one of channel estimation or phase tracking. The device of claim 21, wherein: the frame is obtained via Nss spatial streams; and the orthogonal training field sequences comprise Nss orthogonal training field sequences. The device of claim 21, wherein: the frame comprises Nss spatial streams; and the orthogonal training field sequences comprise fewer than Nss orthogonal training field sequences. The apparatus of claim 23, wherein the orthogonal training field sequence comprises: a first orthogonal training field sequence for a first stream of the Nss spatial streams; A second orthogonal training field sequence of a remainder of the Nss spatial streams. A wireless node, comprising: at least one antenna; a processing system configured to generate a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different spatial stream And a transmitter configured to transmit the frame as a single user (SU), a multi-user (MU) multiple input multiple output (MIMO) transmission, or an orthogonal frequency division via the at least one antenna Multiple Access (OFDMA) transmissions are sent. A wireless node, comprising: at least one antenna; a receiver configured to receive, via the at least one antenna, a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to one Different spatial streams, the frame is transmitted via a single user (SU), a multi-user (MU) multiple-input multiple-output (MIMO) transmission, or an orthogonal frequency division multiple access (OFDMA) transmission. Obtaining; and a processing system configured to perform at least one of channel estimation or phase tracking based on the sequence of training fields. A computer readable medium having stored thereon instructions for performing the following operations: generating a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different Spatial stream; and output the frame for single-user (SU) transmission, one multi-user (MU) multiple-input multiple-output (MIMO) transmission, or one orthogonal frequency division multiple access (OFDMA) transmission Transfer. A computer readable medium having stored thereon instructions for performing the following operations: acquiring a frame having a plurality of orthogonal training field sequences, each orthogonal training field sequence being assigned to a different Space stream, the frame is obtained via a single user (SU) transmission, a multi-user (MU) multiple-input multiple-output (MIMO) transmission, or an orthogonal frequency division multiple access (OFDMA) transmission. And performing at least one of channel estimation or phase tracking based on the training field sequences.