WO2016106753A1

WO2016106753A1 - Channel estimation method and apparatus for wireless local area network

Info

Publication number: WO2016106753A1
Application number: PCT/CN2014/096065
Authority: WO
Inventors: 卢伟山; 林梅露; 刘乐
Original assignee: 华为技术有限公司
Priority date: 2014-12-31
Filing date: 2014-12-31
Publication date: 2016-07-07
Also published as: CN107113266A; CN107113266B

Abstract

Provided is a channel estimation method for a wireless local area network, the method comprising: generating a pre-set number of long training field (LTF) symbols; generating a reference pilot symbol born on an unoccupied sub-carrier, wherein the unoccupied sub-carrier corresponds to a pre-set resource block, and a pre-decoding method of the reference pilot symbol is the same as a pre-decoding method of the pre-set resource block; and sending the LTF symbols and the reference pilot symbol to a station, wherein the LTF symbols and the reference pilot symbol are used for the station to perform channel estimation on a sub-carrier occupied by the pre-set resource block. The present invention can greatly improve the accuracy of channel estimation and enhance system performance by using the channel estimation method of unoccupied sub-carrier assisted interpolation.

Description

Channel estimation method and device for wireless local area network

Technical field

The present invention relates to the field of communications technologies, and in particular, to a channel estimation method and apparatus for a wireless local area network.

Background technique

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation technology widely used in fourth-generation cellular communication systems, such as Long-Term Evolution (LTE) and global microwave interconnection. Worldwide Interoperability for Microwave Access (WiMAX) system, etc. The existing wireless local area network (WLAN) standard based on OFDM technology is composed of gradual evolution of 802.11a, 802.11n, 802.11ac and the like. At present, the IEEE 802.11 standard organization has started the standardization work of the new generation WLAN standard 802.11ax called HEW (High Efficiency WLAN), in which OFDMA (Orthogonal Frequency Division Multiple Access) is The key technology of 802.11ax.

In the downlink OFDMA system, different resource blocks are allocated to different users. Therefore, the AP can communicate with different users by using different precodings on different resource blocks. In this case, the user cannot perform interpolation on the entire band. For channel information, the user needs to extrapolate to estimate the edge subcarrier channel information of the resource block. When a large frequency selective channel is encountered, the extrapolation is quite inaccurate and the performance is seriously degraded.

Summary of the invention

Embodiments of the present invention provide a channel estimation method and apparatus for a wireless local area network, which are used for accurately performing channel estimation.

In a first aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Generating a preset number of long training field LTF symbols;

Generating a reference pilot symbol that is carried on the vacant subcarrier, where the vacant subcarrier corresponds to a preset resource block, and the precoding manner of the reference pilot symbol is the same as the precoding manner of the preset resource block;

Transmitting, to the station, the LTF symbol and the reference pilot symbol, where the LTF symbol and the reference pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block.

In a first possible implementation manner of the first aspect, the LTF symbol is specifically a compressed LTF symbol, and the generated LTF symbol is specifically:

Adding a pilot symbol to the subcarrier with the LTF symbol number ±N _g n, N _g is a positive integer, and n is a subcarrier number;

Performing an inverse discrete Fourier transform (IDFT) on the LTF symbol to obtain a time domain signal of N _g periods;

The compressed LTF symbol is obtained by intercepting one cycle of the N _g periodic time domain signals.

In the first aspect or the first possible implementation manner of the first aspect, the second possible implementation manner of the first aspect is further provided, where the preset number of LTF symbols is specifically greater than Or equal to the number of streams.

In the first aspect or the first or second possible implementation of the first aspect, a third possible implementation manner of the first aspect is also provided, including:

The vacant subcarrier mapping information is sent to the STA, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.

In a second aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Receiving a long training field LTF symbol and a reference pilot symbol sent by the access point AP;

Determining, according to the received LTF symbol, a preset resource block corresponding to first channel information of a subcarrier carrying the LTF symbol;

Determining, according to the received reference pilot symbol, second channel information of the spare subcarrier that carries the reference pilot symbol corresponding to the preset resource block;

Determining, according to the first channel information and the second channel information, the preset resource block The third channel information of the partial subcarriers.

In a first possible implementation manner of the second aspect, the method includes:

And receiving the vacant subcarrier mapping information sent by the access point AP, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.

In a third aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Generating a preset number of long training field LTF symbols;

Generating a phase tracking pilot symbol, the phase tracking pilot symbol being carried on at least one of the most edge subcarriers of the preset resource block, the precoding manner of the phase tracking pilot symbol and the precoding of the preset resource block In the same way;

And transmitting, to the station, the LTF symbol and the phase tracking pilot symbol, where the LTF symbol and the phase tracking pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block.

In a first possible implementation manner of the third aspect, the LTF symbol is specifically a compressed LTF symbol, and the generated LTF symbol is specifically:

In the third aspect or the first possible implementation manner of the foregoing third aspect, the second possible implementation manner of the third aspect is further provided, where the preset number of LTF symbols is specifically greater than Or equal to the number of streams.

In the third aspect or the first or second possible implementation manner of the third aspect, a third possible implementation manner of the third aspect is further provided, including:

The phase tracking pilot symbol mapping information is sent to the STA, and the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.

In a fourth aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Receiving a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP;

Determining, according to the received phase tracking pilot symbol, second channel information of the most edge subcarrier carrying the phase tracking pilot symbol in the preset resource block;

Determining, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.

In a first possible implementation manner of the foregoing fourth aspect, the method includes:

And receiving phase tracking pilot symbol mapping information sent by the AP, where the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.

In a fifth aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Send a long training field LTF symbol to the station;

Sending, to the station, length information of the LTF symbol and user assistance information, the length information characterizing a compression multiple of the LTF symbol, the user assistance information being used to indicate whether the station can use a sub-resource block Carrier assisted channel estimation.

In a first possible implementation manner of the fifth aspect, the compression factor of the LTF symbol is 1, 2, or 4.

In a sixth aspect, the present invention provides a channel estimation method for a wireless local area network, including:

Receiving a long training field LTF symbol sent by the access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate whether the site can use the phase Subcarriers of neighboring resource blocks assist channel estimation;

And determining channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.

In a seventh aspect, the present invention provides a wireless local area network device, including:

a processor, configured to generate a preset number of long training field LTF symbols;

Generating a reference pilot symbol carried on the vacant subcarrier, where the vacant subcarrier corresponds to a preset resource block, and a precoding manner of the reference pilot symbol and a precoding side of the preset resource block Same formula;

a transmitter, configured to send the LTF symbol and the reference pilot symbol to a station, where the LTF symbol and the reference pilot symbol are used by the station to perform channel on a subcarrier occupied by the preset resource block estimate.

In a first possible implementation manner of the seventh aspect, the processor is further configured to:

In the seventh aspect or the first possible implementation manner of the seventh aspect, the second possible implementation manner of the seventh aspect is further provided, where the preset number of LTF symbols is specifically greater than Or equal to the number of streams.

In the seventh aspect or the first or second possible implementation manner of the seventh aspect, a third possible implementation manner of the seventh aspect is further provided, where the transmitter is further used :

In an eighth aspect, the present invention provides a wireless local area network device, including:

a receiver, configured to receive a long training field LTF symbol and a reference pilot symbol sent by the access point AP;

a processor, configured to determine, according to the received LTF symbol, that the preset resource block corresponds to first channel information of a subcarrier that carries the LTF symbol;

In a first possible implementation manner of the eighth aspect, the receiver is further configured to:

In a ninth aspect, the present invention provides a wireless local area network device, including:

a transmitter, configured to send the LTF symbol and the phase tracking pilot symbol to a station, where the LTF symbol and the phase tracking pilot symbol are used by a subcarrier occupied by the station for the preset resource block Perform channel estimation.

In a first possible implementation manner of the ninth aspect, the processor is further configured to:

In the ninth aspect or the first possible implementation manner of the ninth aspect, the second possible implementation manner of the ninth aspect is further provided, where the preset number of LTF symbols is specifically greater than Or equal to the number of streams.

In the ninth aspect or the first or second possible implementation manner of the ninth aspect, a third possible implementation manner of the ninth aspect is further provided, where the transmitter is further used :

In a tenth aspect, the present invention provides a wireless local area network device, including:

a receiver, configured to receive a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP;

a processor, configured to determine, according to the received LTF symbol, that the preset resource block corresponds to the bearer First channel information of subcarriers of the LTF symbol;

In a first possible implementation manner of the foregoing tenth aspect, the receiver is further configured to:

In an eleventh aspect, the present invention provides a wireless local area network device, including:

a transmitter, configured to send a long training field LTF symbol to the station;

In a first possible implementation manner of the eleventh aspect, the LTF symbol has a compression factor of 1, 2, or 4.

According to a twelfth aspect, the present invention provides a wireless local area network device, including:

a receiver, configured to receive a long training field LTF symbol sent by an access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate Whether the station can use the subcarriers of the adjacent resource blocks to assist in channel estimation;

And a processor, configured to determine channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.

In the technical solution disclosed in this embodiment, the channel estimation method using the vacant subcarrier-assisted interpolation can greatly improve the accuracy of channel estimation and improve system performance.

DRAWINGS

1 is a schematic diagram of a frame structure of 802.11a, 802.11n, and 802.11ac;

2 is a schematic diagram of a frame structure of 802.11ax;

Figure 3 is a schematic diagram of a WLAN deployment scenario;

4 is a schematic diagram of a subcarrier according to Embodiment 1 of the present invention;

Figure 5 is a flowchart of a method according to Embodiment 1 of the present invention;

6 is a schematic diagram of a subcarrier index of an LTF symbol according to Embodiment 1 of the present invention;

FIG. 7 is a schematic diagram of a vacant subcarrier index according to Embodiment 1 of the present invention; FIG.

8 is a flowchart of a method according to Embodiment 2 of the present invention;

9 is a flowchart of a method according to Embodiment 3 of the present invention;

10 is a schematic diagram of a phase tracking pilot index according to Embodiment 3 of the present invention;

11 is a flowchart of a method according to Embodiment 4 of the present invention;

12 is a flowchart of a method according to Embodiment 5 of the present invention;

13 is a schematic diagram of a subcarrier for carrying a channel estimation pilot in an LTF symbol according to Embodiment 5 of the present invention;

14 is a schematic diagram of a subcarrier for carrying a channel estimation pilot in another LTF symbol according to Embodiment 5 of the present invention;

Figure 15 is a flowchart of a method according to Embodiment 6 of the present invention;

Figure 16 is a schematic diagram of an apparatus according to Embodiment 7 of the present invention;

Figure 17 is a schematic diagram of an apparatus according to Embodiment 8 of the present invention;

Figure 18 is a schematic diagram of an apparatus according to Embodiment 9 of the present invention;

19 is a schematic diagram of an apparatus according to Embodiment 10 of the present invention;

20 is a schematic diagram of an apparatus according to Embodiment 11 of the present invention;

Figure 21 is a schematic diagram of an apparatus according to Embodiment 12 of the present invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

In the existing WLAN system, there is a big difference between the frame structures of the various systems, wherein the frame structures of 802.11a, 802.11n, and 802.11ac are as shown in FIG. 1, and FIG. 1 is only used for the exemplary pair frame structure. The description does not represent the actual field length and the like. The frame structures of the three standards all have the same Legacy Preamble, including Legacy Short Training Field (L-STF) and Legacy Long Training Field (L-LTF). ) and the traditional signaling field (Legacy Signal field, L-SIG). After the Legacy Preamble field, 802.11a includes a data field (Data), and 802.11n includes a High Throughput Signal Field (HT-SIG) and a High Throughput Short Training Field (HT). -STF), High Throughput Long Training Field (HT-LTF) and Data Field (Data). 802.11ac includes Very High Throughput Signal-A field (VHT). -SIG-A), Very High Throughput Short Training Field (VHT-STF), Very High Throughput Long Training Field (VHT-LTF), Very High Throughput Signal High Throughput Signal-B field (VHT-SIG-B) and data field (Data).

In the subsequent evolution of the WLAN, optionally, a possible future WLAN system, such as 802.11ax or other possible WLAN systems, is provided. Further, 802.11ax is taken as an example, and its possible frame structure is as shown in FIG. 2. In order to be backward compatible with the existing WLAN device, the beginning part of the 802.11ax frame is also a Legacy Preamble field, that is, L-STF, L-LTF and L-SIG fields. The L-SIG field is followed by High Efficiency Signal-1 Field (HE-SIG-1) and High Efficiency Signal-1 Field (HE-SIG-2). Then, the High Efficiency Short Training Field (HE-STF) and the High Efficiency Long Training Field (High Efficiency Long Training Field). HE-LTF), High Efficiency Signal-A field (HE-SIG-B), followed by the HE-SIG-B field is the data field (Data).

It should be noted that, in the future possible WLAN system, the name of the system or the name of the field, etc., may be replaced by any other name, and should not be construed as limiting the scope of the present invention.

A typical WLAN deployment scenario is shown in FIG. 3, including an access point (AP) and at least one station (Station, STA). Exemplarily, in the scenario shown in FIG. 3, the AP communicates with STA1 and STA2, respectively.

The station (English: Station, abbreviation: STA) can be a wireless communication chip, a wireless sensor or a wireless communication terminal. For example: a mobile phone that supports wireless fidelity (English: Wireless Fidelity, referred to as WiFi) communication function, a tablet computer that supports WiFi communication function, a set-top box that supports WiFi communication function, a smart TV that supports WiFi communication function, and a WiFi communication function. Smart wearables and computers that support WiFi communication. Optionally, the site may only support the 802.11ax system. Further optionally, the site may also support multiple WLAN formats such as 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

Access Point (English: Access Point, referred to as AP), also known as wireless access point or hotspot. An AP is a special site that provides access to the site. It can be an access point for mobile users to enter the wired network. It is mainly deployed in the home, inside the building, and inside the campus. The typical coverage radius is tens of meters to hundreds of meters. Of course, it can also be deployed outdoors. An AP is equivalent to a bridge connecting a wired network and a wireless network. Its main function is to connect the wireless network clients together and then connect the wireless network to the Ethernet. At present, the main standard adopted by AP is the Institute of Electrical and Electronics Engineers (English: 802.11 series). Specifically, the AP may be a terminal device or a network device with a WiFi chip. Optionally, the AP may be a device supporting the 802.11ax system. Further, the AP may be a device supporting multiple WLAN systems such as 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

In one embodiment, the subcarriers of the DATA field are allocated as a plurality of resource blocks, so that different resource blocks are flexibly allocated to different sites, and the resource blocks are used to carry uplink and downlink data of the corresponding site; There are at least two consecutive resource blocks that are not used to carry The subcarrier of the data. Such subcarriers that do not carry data between two consecutive resource blocks are referred to as spare subcarriers.

As shown in FIG. 4, for an 802.11ax WLAN implementation, the Discrete Fourier Transform (DFT)/Inverse DFT (IDFT) points in the DATA field are 256, that is, there are 256. Subcarriers, wherein subcarriers-1, 0, 1 are direct current (DC), subcarriers -122 to subcarrier-2, and subcarrier 2 to subcarrier 122 are used to carry data information, that is, 242 sub-carriers The carrier is used to carry data information. Subcarrier-128 to subcarrier-123 and subcarrier 123 to subcarrier 128 are guard bands. Among them, 242 subcarriers for carrying data information are divided into 9 resource blocks, each resource block is 26 subcarriers, and 8 unused subcarriers remain. These 9 resource blocks occupy subcarrier-122 to subcarrier-97 (resource block 1), subcarrier-95 to subcarrier-70 (resource block 2), subcarrier-68 to subcarrier-43 (resource block) 3), subcarrier-41 to subcarrier-16 (resource block 4), subcarrier-14 to subcarrier 14 (resource block 5), subcarrier 16 to subcarrier 41 (resource block (resource block 6), subcarrier 43 to subcarrier 68 (resource block 7), subcarrier 70 to subcarrier 95 (resource block 8), subcarrier 97 to subcarrier 122 (resource block 9). The remaining 8 unused subcarriers are respectively subcarriers -96, -69, -42, -15, 15, 42, 69, 96, referred to herein as spare subcarriers.

FIG. 4 is only an example, and the allocation of subcarriers and resource blocks of the DATA field may also be other forms.

Embodiment 1 of the present invention provides a channel estimation information transmitting method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 5. The specific steps are as follows:

S101. Generate a preset number of long training field LTF symbols.

S102: Generate a reference pilot symbol that is carried on a vacant subcarrier, where the vacant subcarrier corresponds to a preset resource block, and a precoding manner of the reference pilot symbol is the same as a precoding manner of the preset resource block.

S103. Send the LTF symbol and the reference pilot symbol to a station, where the LTF symbol and the reference pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block.

In 802.11ax, Data uses 4 times the number of DFT points in the Legacy Preamble field, called 4x length symbols. For this reason, HE-LTF needs to provide 4x channel estimation, that is, HE-LTF also needs 4x length symbols.

The bandwidth supported by the AP can be divided into S resource blocks, the index of each resource block is s, and the AP schedules K users to perform downlink transmission, and the AP allocates S _k resource blocks to each user without loss of generality. , suppose that each resource block can only be assigned to one user, that is,

And the AP performs M _k data stream transmission with each user.

In S101, the AP generates a preset number of LTF symbols, and the preset number may be, but is not limited to, determined according to system parameters. When multiple data streams are to be transmitted, multiple HE-LTFs are needed to implement channel estimation. Further optional, the preset number is greater than or equal to

Optionally, the AP generates a preset number of compressed LTF symbols. For any compressed LTF symbol, the method is generated as follows:

S1011: Add a pilot symbol to a subcarrier numbered ±N _g n in the LTF symbol, where N _g is a positive integer, optionally, N _g =4, n=1, 2, 3...;

S1012: Perform precoding on each pilot symbol, where the precoding manner used is the same as the precoding manner used by the resource block carrying the pilot symbol;

S1013: Perform IDFT transformation on the LTF symbol to obtain a time domain signal waveform of N _g periods;

S1014: intercepting one cycle of the N _g period time domain signal waveform to form a compressed LTF symbol.

Since the compressed LTF sequence is used, the compression ratio is 4, and the AP/STA can estimate the channel information of the subcarrier index as shown in FIG. 6 by using the compressed LTF sequence, and the AP/STA can interpolate using the interpolation operation. Obtaining channel information of the subcarrier index, and using the channel information, the AP/STA can equalize and decode the data carried by each subcarrier.

In S102, the AP generates a plurality of data symbols, and in each data symbol, allocates the spare subcarriers to the preset resource block, where the preset resource block is a resource block allocated to the specific STA, and the preset resource block may be but not limited. It is determined according to the system resource allocation mode, the user resource scheduling mode, and the like. Exemplarily, as shown in FIG. 7, in a 20M bandwidth system, the entire bandwidth is divided into 9 resource blocks, and 8 data symbols have remaining subcarriers, and subcarriers -96 are allocated to resource blocks 1 and 5 carriers. -69 is allocated to resource block 2, subcarrier-42 is allocated to resource block 3, subcarrier -15 and subcarrier The wave 15 is allocated to the resource block 5, the subcarrier 42 is allocated to the resource block 7, the subcarrier 69 is allocated to the resource block 8, and the subcarrier 96 is allocated to the resource block 9.

Optionally, the embodiment may further include:

S1020: Send vacant subcarrier mapping information to the STA, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.

Specifically, the relationship between the vacant subcarrier and the preset resource block may be a vacant subcarrier corresponding to one or more preset resource blocks adjacent thereto, or may be a vacant subcarrier and a preset one or more presets Corresponding to the resource block, it can also be other mapping modes well known to those skilled in the art, which is not limited in this embodiment.

The AP precodes each reference pilot symbol carried by the vacant subcarrier, where the precoding manner used is the same as the precoding manner used by the preset resource block. Exemplarily, for the resource block s, it is allocated to the user k, and the spare subcarrier n' is allocated to the resource block s for assisting the user k to estimate the channel of the edge subcarrier of the resource block s, then the spare subcarrier n' is filled The signal of the channel estimation reference pilot symbol pre-coded and pre-coded can be expressed as:

y _n' =W _k,n' x _n'

Where W _k,n′ is the M×M _k precoding matrices of the user k in the vacant subcarrier n′, and x _n′ is the M _k ×1 channel estimation reference pilot symbols of the user k in the vacant subcarrier n′ .

Those skilled in the art can understand that the above methods include:

S101a. Generate a preset number of long training field LTF symbols, where the preset quantity is greater than or equal to the number of data streams;

S102a: Generate reference pilot symbols, where the reference pilot symbols are carried in the spare subcarriers, and each of the spare subcarrier units (which may be one or more spare subcarriers according to the continuous spatial subcarriers) And the one or more resource blocks, the precoding manner of the reference pilot symbol is the same as the precoding manner of the corresponding preset resource block; wherein the spare subcarrier is a subcarrier between two consecutive resource blocks ;

S103a: Generate data symbols, where data symbols for different target sites are carried in preset or allocated different resource blocks;

The order of execution is not limited in the above generation process, and the order depends on the new WLAN. The data structure in the system (for example, 802.11ax).

S104. Send the LTF symbol, the reference pilot symbol, and a data symbol, where the LTF symbol and the reference pilot symbol are used by the target station to perform channel estimation on its own resource block to facilitate parsing corresponding data symbols. .

In the downlink OFDMA system as described above, different resource blocks are allocated to different users, so the AP can communicate with different users by using different precodings on different resource blocks. In this case, the user cannot The channel is interpolated to obtain channel information of subcarrier-122 to subcarrier-2 and subcarrier 2 to subcarrier 122. If channel estimation is performed using compressed LTF, the user needs to extrapolate to estimate the edge subcarrier channel of the resource block. Information, but this channel information is inaccurate, and performance loss is severe in the case of a high MCS. In the technical solution disclosed in this embodiment, the channel estimation method using the vacant subcarrier-assisted interpolation can greatly improve the accuracy of channel estimation and improve system performance.

Embodiment 2 of the present invention provides a channel estimation method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 8. The specific steps are as follows:

S201. Receive a long training field LTF symbol and a reference pilot symbol sent by the access point AP.

S202. Determine, according to the received LTF symbol, that the preset resource block corresponds to first channel information of a subcarrier that carries the LTF symbol.

S203. Determine, according to the received reference pilot symbol, second channel information of the spare subcarrier that carries the reference pilot symbol corresponding to the preset resource block.

S204. Determine, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.

Optionally, before the step S201, the embodiment may further include:

S200: Receive vacant subcarrier mapping information sent by the access point AP, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block. Exemplarily, in FIG. 7, it is assumed that the user 1 allocates the resource block 2, that is, the resource block 2 is the preset resource block of the user 1, and the user 1 receives the plurality of LTF symbols, and estimates the bearer channel in the resource block 2. The channel information of the subcarriers of the pilot symbols is estimated, that is, the channel information of subcarrier-96, subcarrier-92, subcarrier-88, ...subcarrier-76, subcarrier-72. User 1 receives the reference pilot symbol and estimates the resulting subcarrier-69 Channel information. Finally, the user 1 obtains the subcarrier-95 to the subcarrier-72 according to the channel information of the subcarrier-96, the subcarrier-92, the subcarrier-88, the ...subcarrier-76, the subcarrier-72, and the subcarrier-69, that is, the resource. Channel information of each subcarrier of block 2.

In this embodiment, the first channel information refers to channel information of a subcarrier that carries the LTF symbol in the preset resource block, and the second channel information refers to channel information of the spare subcarrier that carries the reference pilot symbol in the preset resource block, and the third The channel information refers to channel information of all subcarriers of a preset resource block.

A specific method for determining the first channel information according to the LTF symbol in S202, and determining the second channel information according to the reference pilot symbol in S203. The patent application is not limited, and any person skilled in the art may adopt any prior art or multiple A combination of prior art is implemented, and details are not described herein again.

According to the first channel information determined by S202 and the second channel information determined by S203, in S204, the channel information of each subcarrier in the preset resource block may be determined by, but not limited to, using an interpolation algorithm or the like.

Embodiment 3 of the present invention provides a channel estimation method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 9. The specific steps are as follows:

S301. Generate a preset number of long training field LTF symbols.

S302. Generate a phase tracking pilot symbol, where the phase tracking pilot symbol is carried on at least one of the most edge subcarriers of the preset resource block, where the phase tracking pilot symbol is precoded and the preset resource block is The precoding method is the same;

S303. Send the LTF symbol and the phase tracking pilot symbol to a station, where the LTF symbol and the phase tracking pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block. .

The AP generates a compressed LTF symbol. For details, refer to S101, and details are not described herein.

In S302, the phase tracking pilot symbols are used to assist the user in tracking the phase rotation of each OFDM symbol. Due to the residual frequency offset between the transmitting end and the receiving end, the receiving end will have a phase rotation when receiving the OFDM symbol. For example, considering the p-th OFDM symbol, the received signals on the n sub-carriers after phase rotation are:

Wherein, the equivalent channel estimation at the receiving end is h _{p, n} w _p,n , x _p,n is a phase tracking pilot symbol,

Phase rotation for the pth OFDM symbol, so the receiver can estimate

which is

Therefore, in order for the receiving end to track the phase rotation of the OFDM symbol on the resource block of each OFDM symbol, at least one of the most edge subcarriers may be used in the resource block for carrying the phase tracking pilot symbols, in particular, a resource block is assumed. When occupying subcarrier A to subcarrier B, subcarrier A and subcarrier B are the most edge subcarriers.

Optionally, as shown in FIG. 10, the system is capable of dividing 9 resource blocks, the most edge subcarrier-97 of resource block 1, the edge-subcarrier-70 of resource block 2, and the resource block 3 under the bandwidth of 20M. The most edge subcarrier-43, the most edge subcarrier-41 of resource block 4, the edge-edge subcarriers -14 and 14 of resource block 5, the edge-edge subcarrier 41 of resource block 6, and the edge-edge subcarrier 43 of resource block 7 The most edge subcarrier 70 of the resource block 8 and the most edge subcarrier 97 of the resource block 9 are used to carry the phase tracking pilot symbols of the corresponding resource block.

Optionally, the embodiment may further include:

S3020: Send phase tracking pilot symbol mapping information to the STA, where the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.

The AP pre-codes the phase tracking pilot symbols carried on the most edge subcarriers, and uses the same precoding method as the precoding method used by the preset resource blocks. For a specific implementation manner of the precoding, reference may be made to S102, and details are not described herein again.

Those skilled in the art can understand that the above methods include:

S301a, generating a preset number of long training field LTF symbols;

S302a. Generate a phase tracking pilot symbol, where the phase tracking pilot symbol is carried in a pre The precoding manner of the phase tracking pilot symbol is the same as the precoding manner of the corresponding preset resource block, on the at least one most edge subcarrier of the resource block;

S303a: Generate data symbols, where data symbols for different target sites are carried in preset or allocated different resource blocks;

The order of execution is not limited in the above generation process, and the order depends on the data structure in the new WLAN system (for example, 802.11ax).

S304. Send the LTF symbol, the phase tracking pilot symbol, and a data symbol, where the LTF symbol and the reference pilot symbol are used by the target station to perform channel estimation on its own resource block to facilitate parsing corresponding data. symbol.

In the technical solution disclosed in this embodiment, the channel estimation method using phase tracking pilot symbol assisted interpolation can greatly improve the accuracy of channel estimation and improve system performance.

It should be noted that the solutions disclosed in Embodiment 1 and Embodiment 3 of the present invention are not completely opposite technical solutions. In some scenarios, those skilled in the art can easily think of using the technical solutions disclosed in the two embodiments at the same time. In order to further improve the accuracy of the channel estimation, the combination of the two embodiments is also within the scope of the present invention.

Embodiment 4 of the present invention provides a channel estimation method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 11. The specific steps are as follows:

S401. Receive a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP.

S402. Determine, according to the received LTF symbol, that the preset resource block corresponds to the first channel information of the subcarrier that carries the LTF symbol.

S403. Determine second channel information of the most edge subcarrier that carries the phase tracking pilot symbol in the preset resource block according to the received phase tracking pilot symbol.

S404. Determine, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.

Optionally, before S401, the embodiment may further include:

S400. Receive phase tracking pilot symbol mapping information sent by the AP, where the phase tracking guide The frequency symbol mapping information represents a correspondence between the phase tracking pilot symbols and the preset resource blocks. Exemplarily, as shown in FIG. 10, it is assumed that the user 1 allocates the resource block 2, that is, the resource block 2 is the preset resource block of the user 1, and the user 1 receives the plurality of LTF symbols, and estimates that the resource block 2 is used for the bearer. The channel information of the subcarriers of the channel estimation pilot symbols, that is, the channel information of subcarrier-96, subcarrier-92, subcarrier-88, ...subcarrier-76, subcarrier-72. User 1 receives the phase tracking pilot symbols and estimates the channel information of the most edge subcarrier-70 based on the most edge subcarrier-70 carrying the phase tracking pilot. Finally, the user 1 obtains the subcarrier-95 to the subcarrier-72 according to the channel information of the subcarrier-96, the subcarrier-92, the subcarrier-88, the ...subcarrier-76, the subcarrier-72, and the subcarrier-70, that is, the resource. Channel information of each subcarrier of block 2.

In this embodiment, the first channel information refers to channel information of a subcarrier that carries an LTF symbol in a preset resource block, and the second channel information refers to channel information of a most edge subcarrier that carries a phase tracking pilot symbol in a preset resource block. The third channel information refers to channel information of all subcarriers of the preset resource block.

A specific method for determining the first channel information according to the LTF symbol in S402, and determining the second channel information according to the reference pilot symbol in S403. The patent application is not limited, and any person skilled in the art may adopt any prior art or multiple A combination of prior art is implemented, and details are not described herein again.

According to the first channel information determined by S402 and the second channel information determined by S403, in S404, the channel information of each subcarrier in the preset resource block may be determined by, but not limited to, using an interpolation algorithm or the like.

It should be noted that the solutions disclosed in Embodiment 2 and Embodiment 4 of the present invention are not completely opposite technical solutions. In some scenarios, those skilled in the art can easily think of using the technical solutions disclosed in the two embodiments at the same time. In order to further improve the accuracy of the channel estimation, the combination of the two embodiments is also within the scope of the present invention.

Embodiment 5 of the present invention provides a channel estimation method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 12. The specific steps are as follows:

S501. Send a long training field LTF symbol to the station.

S502. Send length information of the LTF symbol and user assistance information to the station, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate Whether the station can use the subcarriers of adjacent resource blocks to assist in channel estimation.

In the S501, the AP generates the LTF symbol. For the specific implementation, reference may be made to S101, and details are not described herein again.

In S502, LTF symbol length information, i.e., compression ratio LTF symbol is N _{_g,} N _g is defined with reference to the S1011. It should be noted that in 802.11ax, the compression multiple of the LTF symbol has a one-to-one correspondence with the length. Illustratively, when the compression multiple is 4, the length is 3.2us, and when the LTF is not compressed, the length is 12.8. Us. Therefore, in S502, the length information of the LTF symbol can be characterized as a compression multiple or length, and other equivalent representation methods, all within the scope of the present invention.

Optionally, if the LTF symbol can be compressed by 4 times, compressed by 2 times, or not compressed, the length information of the LTF symbol has three possible values, and two bits are required for indication. Further, the 00 indication may be used. The LTF is compressed 4 times, 01 indicates that the LTF is compressed 2 times, and 11 indicates that the LTF symbol is not compressed. It should be noted that the present application does not limit the number of bits of the length information, and those skilled in the art may, but are not limited to, setting according to system parameters or system design requirements.

Alternatively, the user assistance information may be indicated by 1 bit, the bit 0 indicates that the station uses the subcarrier auxiliary channel estimation of the neighboring resource block, and the bit 1 indicates that the station does not use the subcarrier auxiliary channel estimation of the neighboring resource block. Illustratively, when all resource blocks are pre-processed without using precoding, the bit can be set to 0 to indicate that the station uses subcarrier-assisted channel estimation of neighboring resource blocks. When a resource block is pre-processed using a different pre-coding, the bit may be set to 1 to indicate that the station does not use the sub-carrier supplemental channel estimate of the neighboring resource block.

Exemplarily, the LTF symbol of N _g = 4, user 1 allocates resource block 2, then user 1 knows that the subcarrier index of resource block 2 used to carry the channel estimation pilot in the LTF symbol is -96, -92, - 88, -84, -80, 76, -72. Through the user assistance information, the user 1 can determine whether the channel estimation of the edge subcarrier of the resource block 2 can be assisted by the subcarrier-68 of the resource block 3.

Further optionally, when the LTF symbol is compressed by 4 times, the subcarriers used by each resource block in the LTF symbol to carry the channel estimation pilot are as shown in FIG. 13, and when the LTF symbol is compressed twice, each resource block is used to carry the LTF symbol. The subcarriers of the channel estimation pilot are as shown in FIG.

In the technical solution disclosed in this embodiment, the user-assisted interpolation method for channel estimation can greatly improve the accuracy of channel estimation and improve system performance.

It should be noted that, in some scenarios, the technical solution disclosed in Embodiment 5 of the present invention can be used in combination with the solutions disclosed in Embodiment 1 and Embodiment 3 of the present invention to further improve the accuracy of channel estimation. Combinations of solutions are also within the scope of the invention.

Exemplarily, in S502, when the user assistance information indicates that the station cannot use the subcarrier of the adjacent resource block to perform channel estimation, the channel scheme may be separately combined with the technical solution disclosed in Embodiment 1 or Embodiment 3. The channel estimation can also be performed in combination with the technical solutions disclosed in Embodiment 1 and Embodiment 3. It is easily conceivable that even when the user assistance information indicates that the station can use the subcarriers of the adjacent resource blocks to assist in channel estimation, the new technical solution generated by the combination between the above embodiments is also within the scope of the present invention. Inside.

Embodiment 6 of the present invention provides a channel estimation method for a wireless local area network, which is used for channel estimation in a WLAN system. The process of this embodiment is shown in Figure 15. The specific steps are as follows:

S601. Receive a long training field LTF symbol sent by the access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate whether the site can Channel estimation using subcarriers of adjacent resource blocks;

S602. Determine channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.

Exemplarily, when N _g = 4, let user 1 allocate resource block 2, and user 1 determines, according to the length information of the received LTF symbol, that the resource block 2 is used in the LTF symbol to carry the channel estimation pilot. -96, -92, -88, -84, -80, 76, -72. Further, according to the received user assistance information, it is determined whether the edge of the resource block 2 can be improved by using the subcarrier-68 of the resource block 3 Channel estimation of the carrier.

Embodiment 7 of the present invention provides a wireless local area network device 70 for performing channel estimation in a WLAN system, as shown in FIG. 16, including:

The processor 701 is configured to generate a preset number of long training field LTF symbols, and generate reference pilot symbols that are carried on the vacant subcarriers, where the vacant subcarriers correspond to preset resource blocks, The precoding manner of the reference pilot symbol is the same as the precoding manner of the preset resource block;

The transmitter 702 is configured to send the LTF symbol and the reference pilot symbol to a terminal, where the LTF symbol and the reference pilot symbol are used by the terminal to perform subcarriers occupied by the preset resource block. Channel estimation.

Optionally, the processor 701 is further configured to:

Further optionally, wherein the preset number of LTF symbols is specifically greater than or equal to the number of data streams.

Optionally, the transmitter 702 is further configured to:

The apparatus 70 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 1 of the present invention, and details are not described herein again.

Embodiment 8 of the present invention provides a wireless local area network device 80 for performing channel estimation in a WLAN system, as shown in FIG. 17, including:

a receiver 801, configured to receive a long training field LTF symbol and a reference pilot symbol sent by the access point AP;

The processor 802 is configured to determine, according to the received LTF symbol, that the preset resource block corresponds to the first channel information of the subcarrier that carries the LTF symbol;

Optionally, the receiver 801 is further configured to:

The device 80 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 2 of the present invention, and details are not described herein again.

Embodiment 9 of the present invention provides a wireless local area network device 90 for performing channel estimation in a WLAN system, as shown in FIG. 18, including:

The processor 901 is configured to generate a preset number of long training field LTF symbols;

The transmitter 902 is configured to send the LTF symbol and the phase tracking pilot symbol to a station, where the LTF symbol and the phase tracking pilot symbol are used by a sub-occupant of the preset resource block by the station. The carrier performs channel estimation.

Optionally, the processor 901 is further configured to:

Optionally, the transmitter 902 is further configured to:

The apparatus 90 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 3 of the present invention, and details are not described herein again.

It should be noted that the solutions disclosed in Embodiment 7 and Embodiment 9 of the present invention are not completely opposite technical solutions. In some scenarios, those skilled in the art can easily think of using the technical solutions disclosed in the two embodiments at the same time. In order to further improve the accuracy of the channel estimation, the combination of the two embodiments is also within the scope of the present invention.

The embodiment of the present invention provides a wireless local area network device 100 for performing channel estimation in a WLAN system, as shown in FIG.

a receiver 1001, configured to receive a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP;

The processor 1002 is configured to determine, according to the received LTF symbol, that the preset resource block corresponds to the first channel information of the subcarrier that carries the LTF symbol;

Optionally, the receiver 1001 is further configured to:

The apparatus 100 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 4 of the present invention, and details are not described herein again.

It should be noted that the solutions disclosed in Embodiment 80 of the present invention and Embodiment 100 are not completely opposite technical solutions. In some scenarios, those skilled in the art can easily think of using the technical solutions disclosed in the two embodiments at the same time. In order to further improve the accuracy of the channel estimation, the combination of the two embodiments is also within the scope of the present invention.

The embodiment of the present invention provides a wireless local area network device 110 for performing channel estimation in a WLAN system. As shown in FIG. 20, the method includes:

a transmitter 1101, configured to send a long training field LTF symbol to the station;

Sending, to the station, length information of the LTF symbol and user assistance information, the length information characterizing a compression multiple of the LTF symbol, the user assistance information being used to indicate the site Whether channel estimation can be performed using subcarriers of adjacent resource blocks.

Optionally, wherein the LTF symbol has a compression factor of 1, 2, or 4.

The apparatus 110 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 5 of the present invention, and details are not described herein again.

It should be noted that, in some scenarios, the technical solution disclosed in Embodiment 11 of the present invention can be used in combination with the solutions disclosed in Embodiment 7 and Embodiment 9 of the present invention to further improve the accuracy of channel estimation. Combinations of solutions are also within the scope of the invention.

Embodiment 12 of the present invention provides a wireless local area network device 120 for performing channel estimation in a WLAN system, as shown in FIG. 21, including:

a receiver 1201, configured to receive a long training field LTF symbol sent by an access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to Indicating whether the station can use the subcarriers of the adjacent resource blocks to assist in channel estimation;

The processor 1202 is configured to determine channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.

The apparatus 120 disclosed in this embodiment may be used to perform the method disclosed in Embodiment 6 of the present invention, and details are not described herein again.

The device provided by the embodiment of the present invention may be applied to an AP or an STA, and may specifically include a fixed site such as a WLAN router, a WLAN switch, a computer, a server, or the like, and may also include mobile devices such as a mobile phone, a tablet computer, a wearable device, and a notebook computer. Site. Further, the receiver or the transmitter may be a dedicated receiving device or transmitting device, or may be a receiving device that integrates the receiving and transmitting functions. The processor may be an integrated circuit (IC), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or the like, or may be integrated in a baseband processor or a general-purpose In the processor.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general hardware. Based on such understanding, all or part of the steps in the technical solution of the present invention can be used to instruct related hardware through a program. To complete, the program may be stored in a computer readable storage medium, and when executed, the program includes the steps of the method embodiment, such as: ROM/RAM, disk, and optical disc. Wait.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

A channel estimation method for a wireless local area network, the method comprising:

Generating a preset number of long training field LTF symbols;

Generating a reference pilot symbol that is carried on the vacant subcarrier, where the vacant subcarrier corresponds to a preset resource block, and the precoding manner of the reference pilot symbol is the same as the precoding manner of the preset resource block;

Transmitting, to the station, the LTF symbol and the reference pilot symbol, where the LTF symbol and the reference pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block.
The method according to claim 1, wherein the LTF symbol is specifically a compressed LTF symbol, and the generated LTF symbol is specifically:

Adding a pilot symbol to the subcarrier with the LTF symbol number ±N g n, N g is a positive integer, and n is a subcarrier number;

Performing an inverse discrete Fourier transform (IDFT) on the LTF symbol to obtain a time domain signal of N g periods;

The compressed LTF symbol is obtained by intercepting one cycle of the N g periodic time domain signals.
The method according to claim 1 or 2, wherein the preset number of LTF symbols is specifically greater than or equal to the number of data streams.
The method according to any one of claims 1 to 3, wherein the method further comprises:

The vacant subcarrier mapping information is sent to the STA, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.
A channel estimation method for a wireless local area network, the method comprising:

Receiving a long training field LTF symbol and a reference pilot symbol sent by the access point AP;

Determining, according to the received LTF symbol, a preset resource block corresponding to first channel information of a subcarrier carrying the LTF symbol;

Determining, according to the received reference pilot symbol, a bearer corresponding to the preset resource block Referring to second channel information of the spare subcarriers of the pilot symbols;

Determining, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.
The method of claim 5, wherein the method further comprises:

And receiving the vacant subcarrier mapping information sent by the access point AP, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.
A channel estimation method for a wireless local area network, the method comprising:

Generating a preset number of long training field LTF symbols;

Generating a phase tracking pilot symbol, the phase tracking pilot symbol being carried on at least one of the most edge subcarriers of the preset resource block, the precoding manner of the phase tracking pilot symbol and the precoding of the preset resource block In the same way;

And transmitting, to the station, the LTF symbol and the phase tracking pilot symbol, where the LTF symbol and the phase tracking pilot symbol are used by the station to perform channel estimation on a subcarrier occupied by the preset resource block.
The method according to claim 7, wherein the LTF symbol is specifically a compressed LTF symbol, and the generated LTF symbol is specifically:

Adding a pilot symbol to the subcarrier with the LTF symbol number ±N g n, N g is a positive integer, and n is a subcarrier number;

Performing an inverse discrete Fourier transform (IDFT) on the LTF symbol to obtain a time domain signal of N g periods;

The compressed LTF symbol is obtained by intercepting one cycle of the N g periodic time domain signals.
The method according to claim 7 or 8, wherein the preset number of LTF symbols is specifically greater than or equal to the number of data streams.
The method according to any one of claims 7 to 9, wherein the method further comprises:

The phase tracking pilot symbol mapping information is sent to the STA, and the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.
A channel estimation method for a wireless local area network, the method comprising:

Receiving a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP;

Determining, according to the received LTF symbol, a preset resource block corresponding to first channel information of a subcarrier carrying the LTF symbol;

Determining, according to the received phase tracking pilot symbol, second channel information of the most edge subcarrier carrying the phase tracking pilot symbol in the preset resource block;

Determining, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.
The method of claim 11 wherein the method further comprises:

And receiving phase tracking pilot symbol mapping information sent by the AP, where the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.
A channel estimation method for a wireless local area network, the method comprising:

Send a long training field LTF symbol to the station;

Sending, to the station, length information of the LTF symbol and user assistance information, the length information characterizing a compression multiple of the LTF symbol, the user assistance information being used to indicate whether the station can use a sub-resource block Carrier assisted channel estimation.
The method of claim 13 wherein the LTF symbol has a compression factor of 1, 2 or 4.
A channel estimation method for a wireless local area network, the method comprising:

Receiving a long training field LTF symbol sent by the access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate whether the site can use the phase Subcarriers of neighboring resource blocks assist channel estimation;

And determining channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.
A wireless local area network device, characterized in that the device comprises:

a processor, configured to generate a preset number of long training field LTF symbols;

Generating a reference pilot symbol carried on the vacant subcarrier, where the vacant subcarrier corresponds to a preset resource block, and a precoding manner of the reference pilot symbol and a precoding side of the preset resource block Same formula;

a transmitter, configured to send the LTF symbol and the reference pilot symbol to a station, where the LTF symbol and the reference pilot symbol are used by the station to perform channel on a subcarrier occupied by the preset resource block estimate.
The device according to claim 16, wherein the processor is further configured to:

Adding a pilot symbol to the subcarrier with the LTF symbol number ±N g n, N g is a positive integer, and n is a subcarrier number;

Performing an inverse discrete Fourier transform (IDFT) on the LTF symbol to obtain a time domain signal of N g periods;

The compressed LTF symbol is obtained by intercepting one cycle of the N g periodic time domain signals.
The apparatus according to claim 16 or 17, wherein the preset number of LTF symbols is specifically greater than or equal to the number of data streams.
The device according to claims 16 to 18, characterized in that the transmitter is further adapted to:

The vacant subcarrier mapping information is sent to the STA, where the vacant subcarrier mapping information represents a correspondence between the vacant subcarrier and the preset resource block.
A wireless local area network device, characterized in that the device comprises:

a receiver, configured to receive a long training field LTF symbol and a reference pilot symbol sent by the access point AP;

a processor, configured to determine, according to the received LTF symbol, that the preset resource block corresponds to first channel information of a subcarrier that carries the LTF symbol;

Determining, according to the received reference pilot symbol, second channel information of the spare subcarrier that carries the reference pilot symbol corresponding to the preset resource block;

Determining, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.
The apparatus according to claim 20, wherein said receiver is further configured to:

Receiving spare subcarrier mapping information sent by the access point AP, the spare subcarrier mapping information The information represents the correspondence between the spare subcarriers and the preset resource blocks.
A wireless local area network device, characterized in that the device comprises:

a processor, configured to generate a preset number of long training field LTF symbols;

Generating a phase tracking pilot symbol, the phase tracking pilot symbol being carried on at least one of the most edge subcarriers of the preset resource block, the precoding manner of the phase tracking pilot symbol and the precoding of the preset resource block In the same way;

a transmitter, configured to send the LTF symbol and the phase tracking pilot symbol to a station, where the LTF symbol and the phase tracking pilot symbol are used by a subcarrier occupied by the station for the preset resource block Perform channel estimation.
The device according to claim 22, wherein the processor is further configured to:

Adding a pilot symbol to the subcarrier with the LTF symbol number ±N g n, N g is a positive integer, and n is a subcarrier number;

Performing an inverse discrete Fourier transform (IDFT) on the LTF symbol to obtain a time domain signal of N g periods;

The compressed LTF symbol is obtained by intercepting one cycle of the N g periodic time domain signals.
The apparatus according to claim 22 or 23, wherein the preset number of LTF symbols is specifically greater than or equal to the number of data streams.
The device according to claims 22 to 24, characterized in that the transmitter is further adapted to:

The phase tracking pilot symbol mapping information is sent to the STA, and the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.
A wireless local area network device, characterized in that the device comprises:

a receiver, configured to receive a long training field LTF symbol and a phase tracking pilot symbol sent by the access point AP;

a processor, configured to determine, according to the received LTF symbol, that the preset resource block corresponds to first channel information of a subcarrier that carries the LTF symbol;

Determining, according to the received phase tracking pilot symbol, the bearer in the preset resource block Phase tracking the second channel information of the most edge subcarrier of the pilot symbol;

Determining, according to the first channel information and the second channel information, third channel information of all subcarriers of the preset resource block.
The apparatus according to claim 26, wherein said receiver is further configured to:

And receiving phase tracking pilot symbol mapping information sent by the AP, where the phase tracking pilot symbol mapping information represents a correspondence between the phase tracking pilot symbol and the preset resource block.
A wireless local area network device, characterized in that the device comprises:

a transmitter, configured to send a long training field LTF symbol to the station;

Sending, to the station, length information of the LTF symbol and user assistance information, the length information characterizing a compression multiple of the LTF symbol, the user assistance information being used to indicate whether the station can use a sub-resource block Carrier assisted channel estimation.
The apparatus according to claim 28, wherein said LTF symbol has a compression factor of 1, 2 or 4.
A wireless local area network device, characterized in that the device comprises:

a receiver, configured to receive a long training field LTF symbol sent by an access point, length information of the LTF symbol, and user assistance information, where the length information represents a compression multiple of the LTF symbol, and the user assistance information is used to indicate Whether the station can use the subcarriers of the adjacent resource blocks to assist in channel estimation;

And a processor, configured to determine channel information of all subcarriers in the resource block according to the long training field LTF symbol, the length information, and the user assistance information.