Wireless local area network data transmission method and device

Abstract

A HE-LTF transmission method, with a total number of space-time streams N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF ; The HE-LTF frequency domain sequence is determined by the transmission bandwidth and the HE-LTF mode; the HE-LTF frequency domain sequence is not limited to the HE-LTF mode sequence in the 1x mode mentioned in the implementation manner; according to the OFDM symbol number N HELTF And the determined HELTF frequency domain sequence sends a time domain signal. The above scheme has a lower PAPR value.

Description

Technical Field

[0001] The embodiments of the present invention relate to communication technology, and in particular to a method and device for wireless local area network data transmission. Background Art

[0002] Wireless Local Area Networks (WLAN) is a data transmission system that uses radio frequency (RF) technology to replace the local area network composed of old twisted copper wires, so that the wireless local area network can use a simple access architecture to allow users to pass through it to achieve the purpose of information transmission. The development and application of WLAN technology has profoundly changed people's communication and working methods, bringing people unprecedented convenience. With the widespread application of smart terminals, people's demand for data network traffic is growing. The development of WLAN is inseparable from the formulation and promotion of its standards. Among them, the IEEE802.11 series is the main standard, mainly 802.11, 802.11b / g / a, 802.11n, and 802.11ac. Except for 802.11 and 802.11b, other standards use Orthogonal Frequency Division Multiplexing (OFDM) technology as the core technology of the physical layer.

[0003] Channel estimation is the process of estimating the channel parameters that the transmitted signal passes through based on the received signal under certain criteria. The performance of the wireless communication system is greatly affected by the wireless channel, such as shadow fading and frequency selective fading, which makes the propagation path between the transmitter and the receiver very complicated. The wireless channel is not fixed and predictable like the wired channel, but has a lot of randomness. In the coherent detection of the OFDM system, it is necessary to estimate the channel, and the accuracy of the channel estimation will directly affect the performance of the entire system.

[0004] In the above WLAN standards with OFDM technology as the core, a common point is that the long training field (LTF) that can be used for channel estimation is specified in the physical layer. For example, the format of the high efficiency (HE) physical layer protocol data unit (PPDU) specified in the 802.11ax standard is as follows: Figure 1 As shown, the HE-LTF field is a high-efficiency long training field used for data part channel estimation. The field can contain one or more HE-LTF codewords, and each codeword is an OFDM symbol.

[0005] In order to improve the system throughput, OFDMA technology is introduced in the 802.11ax standard, and the corresponding physical layer subcarrier spacing is also increased from the existing Reduce to The Fourier transform period of the OFDM symbol in the physical layer data part is also determined by becomes Sometimes the subcarrier spacing becomes The above different OFDM symbol formats are referred to as 4x, 2x and 1x modes respectively.

[0006] As the 802.11ax standard gradually evolves, the subcarrier patterns at 20MHz, 40MHz, 80MHz, and 160 / 80+80MHz bandwidths are as follows: Figures 2 to 4 As shown in the figure, the subcarrier pattern of the left 80MHz bandwidth and the right 80MHz bandwidth of 160 / 80+80MHz is the same as the subcarrier pattern of the 80MHz bandwidth. The subcarrier pattern shows the possible position and size of the resource block when it is scheduled.

[0007] Among them, under 20MHz bandwidth, the pilot subcarrier positions of 242RU (Resource Unit) are ±22, ±48, ±90, ±116; under 40MHz bandwidth, the pilot subcarrier positions of 484RU are ±10, ±36, ±78, ±104, ±144, ±170, ±212, ±238; under 80MHz bandwidth, the pilot subcarrier positions of 996RU are ±24, ±92, ±158, ±226, ±266, ±334, ±400, ±468.

[0008] In order to further improve the system efficiency in different scenarios, the HE-LTF field needs to support the aforementioned 4x, 2x and 1x mode OFDM symbols.

[0009] like Figure 5 As shown, taking 20MHz bandwidth as an example, when the subcarrier position is marked as -128, -127, ..., -2, -1, 0, 1, 2, ..., 127, the subcarriers carrying the long training sequence of the HE-LTF codeword in 4x mode are located at -122, -121, ..., -3, -2, 2, 3, ..., 121, 122, and the rest are empty subcarriers. The subcarrier spacing is

[0010] The subcarriers of the HE-LTF codewords in 2x mode carrying long training sequences are located at -122, -120, ..., -4, -2, 2, 4, ..., 120, 122, and the rest are empty subcarriers; equivalently, the positions of the subcarriers can be marked as -64, -63, ..., -2, -1, 0, 1, 2, ..., 63, then the subcarriers of the HE-LTF codewords in 2x mode carrying long training sequences are located at -61, -60, ..., -2, -1, 1, 2, ..., 60, 61, and the rest are empty subcarriers. At this time, the subcarrier spacing is

[0011] Similarly, the subcarriers of the HE-LTF codewords in 1x mode carrying long training sequences are concentrated at -120, -116, ..., -8, -4, 4, 8, ..., 116, 120, and the rest are empty subcarriers; equivalently, the positions of the subcarriers can be marked as -32, -31, ..., -2, -1, 0, 1, 2, ..., 31, then the subcarriers of the HE-LTF codewords in 1x mode carrying long training sequences are located at -30, -29, ..., -2, -1, 1, 2, ..., 29, 30, and the rest are empty subcarriers. At this time, the subcarrier spacing is

[0012] Currently, only 4x HE-LTF and 2x HE-LTF sequences have been determined, and the 1x HE-LTF sequence has not yet been determined. How to define the 1x HE-LTF sequence is still an open question.

[0013] In the 11n and 11ac standards, the subcarrier spacing is The 20MHz HT / VHT LTF sequence is defined as follows.

[0014] BB_LTF_L={+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,+1,+1}

[0015] BB_LTF_R={+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,-1,-1}

[0016] LTF left ={BB_LTF_L,BB_LTF_L}={+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,+1,+1}

[0017] LTF right={BB_LTF_R,-1*BB_LTF_R}={+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,-1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,+1,+1,+1}

[0018] VHT-LTF 56 (-28:28) = {+1,+1,LTF left ,0,LTF right ,-1,-1}

[0019] However, the subcarriers carrying the long training sequence of the 1xHE-LTF symbol are located at -30, -29, ..., -2, -1, 1, 2, ..., 29, 30, a total of 60 non-empty subcarriers, and the LTF sequence in the existing 11n and 11ac standards cannot be directly used. The remaining bandwidths also have similar problems. Summary of the invention

[0020] In order to reduce the PAPR of a wireless local area network, the present invention provides a HE-LTF transmission method, wherein the total number of space-time streams N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF ; The HE-LTF frequency domain sequence is determined by the transmission bandwidth and the HE-LTF mode; the HE-LTF frequency domain sequence is not limited to the HE-LTF mode sequence in the 1x mode mentioned in the embodiment; according to the OFDM symbol number N HELTF And the determined HELTF frequency domain sequence sends a time domain signal.

[0021] And, accordingly, a HE-LTF transmission method, obtaining the transmission bandwidth BW according to the information carried by the signaling field in the preamble code, the total number of space-time streams N STS , and the mode of the HE-LTF domain; the total number of space-time streams N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF ; The corresponding HE-LTF frequency domain sequence is determined by the transmission bandwidth and the mode of the HE-LTF domain, and the HE-LTF frequency domain sequence includes but is not limited to the HE-LTF mode sequence under the 1x mode mentioned in the implementation manner; the channel estimation value of the corresponding subcarrier position is obtained by the received HE-LTF domain and the determined frequency domain sequence.

[0022] Through simulation and comparison, the HE-LTF mode sequence in the 1x mode in the embodiment of the present invention enables the system to have a very low PAPR value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a simple diagram of a format of HE PPDU;

[0025] Figure 2 It is a schematic diagram of the subcarrier pattern under 20MHz bandwidth;

[0026] Figure 3 It is a schematic diagram of the subcarrier pattern under 40MHz bandwidth;

[0027] Figure 4 It is a schematic diagram of the subcarrier pattern under 80MHz bandwidth;

[0028] Figure 5 This is a simple comparison diagram of 1x, 2x, and 4x OFDM symbols in the frequency domain;

[0029] Figure 6 A simple schematic diagram of the system architecture of an embodiment of the present invention;

[0030] Figure 7 A simple schematic diagram of HE-LTF field generation and transmission when sending SU or downlink DL MU MIMO data packets;

[0031] Figure 8 A simple schematic diagram of HE-LTF field generation and transmission when sending UL MU MIMO data packets;

[0032] Fig. 9A ,9B,9C is a block diagram of a data transmission device 20M 1x HE-LTF subcarrier position B transmitting end in an embodiment of the present invention.

[0033] Fig.10 This is a block diagram of a data transmission device 20M 1x HE-LTF subcarrier position B receiving end according to an embodiment of the present invention.

[0034] Fig.11 It is a simple schematic diagram of a data transmission device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The solutions of the embodiments of the present invention are applicable to a WLAN network system. Figure 6 Schematic diagram of applicable scenarios of the pilot transmission method in a wireless local area network provided by the first embodiment of the present invention. Figure 6 As shown, the WLAN network system may include an access station 101 and at least two stations 102 .

[0037] Access Point (AP), also known as wireless access point, bridge or hotspot, can access a server or communication network.

[0038] Station (STA), also known as user equipment, can be a wireless sensor, wireless communication terminal or mobile terminal, such as a mobile phone (or "cellular" phone) supporting WiFi communication function and a computer with wireless communication function. For example, it can be a portable, pocket-sized, handheld, computer-built-in, wearable, or vehicle-mounted wireless communication device that supports WiFi communication function, which exchanges communication data such as voice and data with the wireless access network. Those skilled in the art know that some communication devices may have the functions of the above-mentioned access points or stations at the same time, which is not limited here.

[0039] Since 1xHE-LTF will be more applied to OFDM rather than OFDMA scenarios, there is no need to consider the PAPR value of the HE-LTF symbol generated when scheduling different RUs. It is only necessary to consider the PAPR value of the HE-LTF symbol when performing OFDM transmission under each bandwidth, such as 242RU under 20MHz, 484RU under 40MHz, and 996RU under 80MHz. Therefore, the present invention uses BB_LTF_L, BB_LTF_R, LTF_L with excellent PAPR properties. left ,LTF right Based on the sequence, a series of expansion operations are performed on it to obtain a new 1x HE-LTF sequence with low PAPR characteristics under different bandwidths. The sequence -1*BB_LTF_L in the following text means that the polarity of each value in the BB_LTF_L sequence is flipped, that is, 1 becomes -1, and -1 becomes 1. left ,-1*LTF right The same goes for this.

[0040] The present invention provides a method for a transmitter to send a SU (single user) data packet or a DL-MU-MIMO (DownLink Multi-user Multiple in Multiple out) data packet, including a process of generating a HE-LTF domain:

[0041] Total space-time flow number N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF ;

[0042] The HE-LTF frequency domain sequence is determined by the transmission bandwidth and the HE-LTF mode; the HE-LTF frequency domain sequence includes but is not limited to the sequence mentioned in the embodiment;

[0043] According to the OFDM symbol number N HELTF And the determined HELTF frequency domain sequence sends a time domain signal.

[0044] Specifically, on the sending end:

[0045] 101. From the total space-time flow number N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF , the following Table 1 gives the specific corresponding relationship.

[0046] <![CDATA[N STS ]]> <![CDATA[N HELTF ]]> 1 1 2 2 3 4 4 4 5 6 6 6 7 8 8 8

[0047] Table 1

[0048] 102. Determine a HELTF frequency domain sequence based on the transmission bandwidth and the HELTF mode. For example, when the transmission bandwidth is BW=20 MHz and the HE-LTF domain mode is 1x, it corresponds to the HELTF sequence in the first embodiment.

[0049] 103. If N HELTF >1, determine the orthogonal mapping matrix A used is N HELTF OK, N HELTF In particular, N HELTF =1, the orthogonal mapping matrix A degenerates to 1. The sequence value carried by the subcarrier of each OFDM symbol in the HELTF domain is multiplied by the orthogonal mapping matrix A as follows. Figure 7 As shown, the number of space-time flows is N STS When , the sequence value carried by the kth subcarrier of the nth OFDM symbol of the i-th spatial stream in the HE-LTF field is multiplied by where i=1,...N STS ,n=1,LN HELTF .

[0050] The definition of the orthogonal mapping matrix A is as follows.

[0051]

[0052] Where K Pilot is the pilot subcarrier set, and the P matrix is ​​defined as w=exp(-j2π / 6)

[0053]

[0054] The R matrix is ​​defined as [R] m,n =[P] 1,n .

[0055] 104. Apply different cyclic shift delays to each space-time stream in the HE-LTF domain. The cyclic shift values ​​corresponding to each space-time stream are shown in Table 2 below.

[0056]

[0057] Table 2

[0058] 105. Map the space-time stream of the HE-LTF domain to the transmission link. If the total number of transmission links is N TX , the total number of space-time flows is N STS , then the antenna mapping matrix Q of the kth subcarrier k N TX Row N STS The Q matrix may use the matrix defined in Section 20.3.11.11.2 of the 802.11n standard.

[0059] 106. Perform inverse discrete Fourier transform to obtain a time domain signal in the HE-LTF domain and send the time domain signal.

[0060] On the receiving end:

[0061] 201. Obtain the transmission bandwidth BW and the total number of space-time streams N according to the information carried by the signaling field in the preamble code. STS , and the mode of the HE-LTF domain. The mode of the HE-LTF domain is also called the mode of the HE-LTF symbol, that is, the aforementioned 1x mode, 2x mode, or 4x mode.

[0062] 202. From the total space-time flow number N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF .

[0063] 203. Determine the corresponding HE-LTF frequency domain sequence according to the transmission bandwidth and the mode of the HE-LTF domain; obtain the channel estimation value of the corresponding subcarrier position according to the received HE-LTF domain and the determined frequency domain sequence.

[0064] In another example, when the transmitter sends a UL-MU-MIMO (Up Link Multi-user Multiple inMultipleout) data packet, the HE-LTF domain generation method is different from sending SU and DL-MU-MIMO data packets in that: before the non-AP site sends the UL-MU-MIMO data packet, the AP needs to indicate the uplink scheduling information through a trigger frame, including the identifier of the scheduled site, the transmission bandwidth, the total number of space-time streams (or the number of HE-LTF symbols), and the spatial stream number assigned to itself.

[0065] On the sending side:

[0066] 301. From the total space-time flow number N STS Determine the number of OFDM symbols N contained in the HE-LTF field HELTF If the scheduling signaling includes the number of HE-LTF symbols, this step can be omitted.

[0067] 302. Determine a HELTF frequency domain sequence based on the transmission bandwidth and the HELTF mode. For example, when the transmission bandwidth is BW=40 MHz and the HE-LTF domain mode is 1x, it corresponds to the HELTF sequence in the second embodiment.

[0068] 303. Mask (i.e., XOR) the HELTF sequence using the row sequence corresponding to the spatial stream number assigned by the transmitter (i.e., the scheduled user) in the 8*8 P matrix. For example, the HELTF initial sequence is {L1, L2, ..., L m}, when the spatial stream number assigned to the transmitter is {i1,i2,i3}, the mask sequence selects the {i1,i2,i3}th row in the 8*8 P matrix, then the masked HELTF sequence of the i1th spatial stream is

[0069]

[0070] mod means remainder. Similarly, we can get and

[0071] 304. Determine the orthogonal mapping matrix A used as N HELTF OK, N HELTF The sequence value carried by the subcarrier of each OFDM symbol in the HE-LTF domain is multiplied by the orthogonal mapping matrix A as follows.

[0072] For example, Figure 8As shown, when the spatial stream number assigned to the transmitter (i.e., the scheduled user) is {i1, i2, i3}, the sequence value HELTF carried by the kth subcarrier of the nth OFDM symbol of the HE-LTF field is k 'Multiply by Where i=i1,i2,i3,n=1,LN HELTF . Optional, Figure 7 The A matrix in can also be replaced by the P matrix.

[0073] The remaining steps are similar to the previous example and will not be repeated here.

[0074] Receiver: Since it is UL-MU-MIMO transmission, the AP itself knows the relevant scheduling information and can directly execute the channel estimation algorithm.

[0075] 401. Obtain a channel estimation value of a corresponding subcarrier position from the received HE-LTF domain and a known frequency domain sequence.

[0076] It should be understood that the CSD value and the Q matrix in the above examples are only examples, and other values ​​may be selected, which are not limited in the embodiments of the present invention.

[0077] The following is an example of HE-LTF sequences in 1x mode with various bandwidth preferences:

[0078] Embodiment 1 of the present invention

[0079] Scenario: 1x HE-LTF subcarrier position A in 20MHz bandwidth

[0080] Preferably, additional 8 subcarrier values ​​are added based on two BB_LTF_L and two BB_LTF_R sequences to generate a 1x HE-LTF sequence. To ensure simple implementation, the 8 subcarrier values ​​are selected between {1, -1}.

[0081] A better sequence is: HE-LTF 60 (-120:4:120) = {BB_LTF_L, +1, -1, -1*BB_LTF_L, -1, -1, 0, +1, +1, BB_LTF_R, -1, -1, BB_LTF_R}, which can also be expressed as HE-LTF 60(-120:4:120)={+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,+1,-1,-1,-1,+1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,-1,-1,0,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,-1,-1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,-1}, which also includes the sequence obtained by flipping the polarity of each value of the sequence (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0, that is, null subcarriers. Here, -120:4:120, as described above, represents -120, -116, ..., -8, -4, 0, 4, 8, ..., 116, 120. At this time, the corresponding pilot subcarrier positions are ±48, ±116, that is, there are 4 pilot subcarriers.

[0082] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.1121 dB.

[0083] Refer to Table 3, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when multiple spatial streams are used. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused is only 0.2586dB, and the worst PAPR value is 4.2136. (The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 20MHz bandwidth are both greater than 5dB.)

[0084]

[0085] Table 3

[0086] Suboptimal, sequence: HE-LTF 60 (-120:4:120) = {+1,-1,-1,BB_LTF_L,-1,BB_LTF_L,0,BB_LTF_R,-1,-1*BB_LTF_R,+1,+1,-1}, which can also be expressed as HE-LTF 60(-120:4:120)={+1,-1,-1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,+1,+1,0,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,-1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,+1,+1,+1,-1}, which also includes the sequence obtained by flipping the polarity of each value of the sequence (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0.

[0087] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.0821 dB.

[0088] Refer to Table 4, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is 0.2398 dB, and the worst PAPR value is 4.3219 dB.

[0089]

[0090] Table 4

[0091] Embodiment 2 of the present invention

[0092] Scenario: 1x HE-LTF subcarrier position B in 20MHz bandwidth

[0093] In order to facilitate the channel estimation interpolation operation, another subcarrier position pattern of HE-LTF in 1x mode with 20MHz bandwidth is -122:4:122. Preferably, BB_LTF_L, BB_LTF_R, LTF left , LTF right The 1x HE-LTF sequence is generated by adding 10 additional subcarrier values ​​based on the sequence. To ensure simple implementation, the 10 subcarrier values ​​are selected between {1, -1}. The preferred sequence is: HE-LTF 62 (-122:4:122) = {LTF right ,-1,+1,-1,-1,+1,-1,-1,-1,+1,+1,LTF left}, can also be expressed as HE-LTF 62(-122:4:122)={+1,-1,-1,+1,+1,-1,+1,-1,-1,-1,-1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1}, which also includes the sequence obtained by flipping the polarity of each value of the sequence (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0, that is, null subcarriers. Here, -122:4:122, as described above, represents -122, -118, ..., -6, -2, 2, 6, ..., 118, 122. At this time, the corresponding pilot subcarrier positions are ±22, ±90, that is, there are 4 pilot subcarriers.

[0094] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 3.7071 dB.

[0095] Refer to Table 5, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams (caused by the P matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard) is only 0.2657, and the worst PAPR value is 3.9728. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 20MHz bandwidth are both greater than 5dB.

[0096]

[0097] Table 5

[0098] Suboptimal, sequence: HE-LTF 62 (-122:4:122) = {BB_LTF_L, +1, +1, -1, -1*BB_LTF_L, -1, -1, +1, -1, -1*BB_LTF_R, +1, -1, -1, -1*BB_LTF_R}, which can also be expressed as HE-LTF 62(-122:4:122)={+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,+1,+1,-1,-1,-1,+1,+1,+1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,+1}, which also includes the sequence obtained by flipping the polarity of every value of the sequence (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0.

[0099] In the case of a single spatial stream, the PAPR value of the 1xHE-LTF symbol generated according to the sequence is only 3.8497 dB.

[0100] Referring to Table 6, the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams are listed. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is 0.4069, and the worst PAPR value is 4.2566dB.

[0101]

[0102] Table 6

[0103] It should be noted that, for the second embodiment of the present invention, in the HE-LTF subcarrier position B scenario of the 1x mode at a bandwidth of 20 MHz, the time domain sequence obtained after the IFFT operation on the 1x HE-LTF sequence is LTF t ={LTF tq ,-1*LTF tq ,LTF tq ,-1*LTF tq}, where LTF tq The first 1 / 4 of the time domain sequence, the sender can directly send the LTF with a cyclic prefix (CP, also called GI) tq Sequence Tx_LTF tq It should be noted that the CP sequence refers to the original sequence before truncation (i.e., sequence LTF). t ) to obtain the CP sequence. If the transmitter uses 256-point IFFT, refer to Fig. 9A , which is a simple schematic diagram of the transmitter of 20M 1x HE-LTF subcarrier position B, and finally performs time domain windowing operation and sends it.

[0104] In another equivalent solution, the transmitter can perform IFFT operation on the 1x HE-LTF sequence to obtain a time domain sequence of LTF t ={LTF tq ,-1*LTF tq ,LTF tq ,-1*LTF tq}, where LTF tq The first 1 / 4 of the time domain sequence is then cut off to get the sequence LTF tq , and for the truncated sequence LTF tq Get LTF tq The CP of the CP sequence is then inverted (i.e., all CP values ​​are inverted) and added to the LTF. tq The transmission sequence Tx_LTF is obtained above tq , and finally perform time domain windowing and send. If the transmitter uses 256-point IFFT, refer to Fig. 9B , which is an equivalent simple schematic diagram of the 20M 1x HE-LTF subcarrier position B transmitter.

[0105] In another equivalent solution, the transmitter can perform IFFT operation on the 1x HE-LTF sequence to obtain a time domain sequence of LTF t ={LTF tq ,-1*LTF tq ,LTF tq ,-1*LTF tq}, where LTF tq is the first 1 / 4 of the time domain sequence. Then, for the sequence LTF t Get LTF t CP and add to LTF t The sequence LTF is obtained earlier tp Finally, extract the sequence LTF tp CP and LTF t The first 1 / 4 (i.e. the CP and LTF tq ) get the transmission sequence Tx_LTF tq , and finally perform time domain windowing and send. If the transmitter uses 256-point IFFT, refer to Fig. 9C , which is an equivalent simple schematic diagram of the 20M 1x HE-LTF subcarrier position B transmitter.

[0106] Accordingly, let the 1x HE-LTF time sequence received by the receiver be Rx_LTF tqr , after removing CP, it is LTF tqr , the receiver can first expand the time series into LTF tr ={LTF tqr ,-1*LTFtqr ,LTF tqr ,-1*LTF tqr}, and then perform FFT operation on it. If the receiving end uses 256-point FFT, refer to Fig.10 , which is a simple schematic diagram of the receiving end of 20M 1x HE-LTF subcarrier position B.

[0107] Fig.10 In the example, the time sequence of the 1x HE-LTF part received by the receiver is Rx_LTF tq , after removing the previous CP, we get the sequence LTF tqr . Then, LTF tqr Repeat four times, and invert the second and fourth repeated signs to get LTF tr ={LTF tqr ,-1*LTF tqr ,LTF tqr ,-1*LTF tqr}. Then, LTF tr A 256-point FFT operation is performed to obtain the received frequency domain 1xHE-LTF sequence, which is called 1x Rx_HE-LTF.

[0108] Embodiment 3 of the present invention

[0109] Scenario: 40MHz bandwidth

[0110] With the following two sets of sequences LTF left and LTF right An additional 18 subcarrier values ​​are added to the basis to generate a 1x HE-LTF sequence. To ensure simple implementation, the 18 subcarrier values ​​are selected between {1, -1}.

[0111] The better sequence is: HE-LTF 122 (-244:4:244) = {LTF right ,-1,LTF right ,-1,-1,-1,+1,+1,-1,-1,-1,0,+1,+1,+1,-1,-1,-1,-1,+1,-1*LTF left ,+1,LTF left}, can also be expressed as HE-LTF 122(244:4:244)={+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,-1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,+1,-1,-1,-1,+1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,-1,+1,+1,-1,-1,0,+1,+1,+1,-1,-1,-1,-1,-1,-1. ,+1,-1,-1,+1,+1,-1,-1,+1,-1,-1,-1,-1,-1,-1,-1,+1,-1,+1,-1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,+1,-1,+1,+1,+1,+1}, and also includes the sequence obtained after every value of the sequence is flipped in polarity (that is, 1 becomes -1, -1 becomes 1, and 0 remains unchanged), and the other subcarriers are 0, that is, null subcarriers. Here, -244:4:244 means -244, -240, ..., -8, -4, 0, 4, 8, ..., 240, 244. At this time, the corresponding pilot subcarrier positions are ±36, ±104, ±144, ±212, that is, there are 8 pilot subcarriers.

[0112] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.6555 dB.

[0113] Refer to Table 7, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is only 0.5273dB, and the worst PAPR value is 4.6555dB. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 40MHz bandwidth are greater than 6dB in the worst case.

[0114]

[0115] Table 7

[0116] Suboptimal, sequence: HE-LTF 122 (-244:4:244) = {LTF right,-1,+1,+1,+1,-1,+1,-1,-1,+1,-1*LTF left ,0,-1*LTF right ,+1,-1,-1,-1,-1,+1,+1,+1,+1,-1*LTF left}, can also be expressed as HE-LTF 122 (244:4:244)={+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,-1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,0,-1,+1,-1,-1,+1,-1,+1,-1,+1, The subcarriers are 0, i.e., null subcarriers. Here, -244:4:244 means -244, -240, ..., -8, -4, 0, 4, 8, ..., 240, 244. At this time, the corresponding pilot subcarrier positions are ±36, ±104, ±144, ±212, that is, there are 8 pilot subcarriers.

[0117] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.6831 dB.

[0118] Refer to Table 8, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is only 0.3397dB, and the worst PAPR value is 4.8335dB. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 40MHz bandwidth are greater than 6dB in the worst case.

[0119]

[0120] Table 8

[0121] Again, the best sequence is: HE-LTF 122 (-244:4:244)={+1,+1,+1,LTF left ,+1,LTF right ,+1,-1,-1,+1,-1,0,+1,-1*LTF left ,-1,-1*LTF right ,-1,-1,+1,+1,-1,+1,-1}, which can also be expressed as HE-LTF 122 (244:4:244)={+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,+1,-1,-1,-1,+1,+1,-1,-1,+1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,0,+1,-1,+1,+1,-1,-1,+1,-1,-1, The subcarriers are 0, i.e., null subcarriers. Here, -244:4:244 means -244, -240, ..., -8, -4, 0, 4, 8, ..., 240, 244. At this time, the corresponding pilot subcarrier positions are ±36, ±104, ±144, ±212, that is, there are 8 pilot subcarriers.

[0122] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 5.1511 dB.

[0123] Refer to Table 9, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is only 0.1dB, and the worst PAPR value is 5.1511dB. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 40MHz bandwidth are greater than 6dB in the worst case.

[0124]

[0125] Table 9

[0126] The less optimal sequence is: HE-LTF 122 (-244:4:244)={+1,+1,-1,LTF left ,+1,LTF right ,+1,+1,-1,+1,+1,0,-1,-1*LTF left ,-1,-1*LTF right ,-1,+1,+1,+1,+1,+1,-1}, which can also be expressed as HE-LTF 122 (244:4:244)={+1,+1,-1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,0,-1,-1,-1,+1,-1,+1,-1,-1,+1,-1, The subcarriers are 0, i.e., null subcarriers.

[0127] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.9848 dB.

[0128] Refer to Table 10, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The phase difference is caused by the A matrix, which is defined in Section 22.3.8.3.5 of the 11ac standard. Among them, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is 0.3083dB, and the worst PAPR value is 5.2026dB.

[0129]

[0130]

[0131] Table 10

[0132] Embodiment 4 of the present invention

[0133] Scenario: 80MHz bandwidth

[0134] With the following two sets of sequences LTF left and LTF right An additional 42 subcarrier values ​​are added to the basis to generate a 1x HE-LTF sequence. To ensure simple implementation, the 42 subcarrier values ​​are selected between {+1, -1}.

[0135] The best sequence is: HE-LTF 250 (-500:4:500)={-1,-1,+1,+1,+1,+1,+1,-1,-1*LTF left ,-1*LTF right ,+1,-1,-1,-1,-1,-1,-1,+1,LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,+0,-1,+1,+1,-1,-1,LTF left ,LTF right ,-1,+1,-1,-1,+1,-1,-1,+1,LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,-1,+1,+1}, which can also be expressed as HE-LTF 250(-500:4:500)={-1,-1,+1,+1,+1,+1,+1,-1,-1,-1,+1,+1,-1,+1,-1,-1,+1,-1,-1,-1,-1,-1,-1,+1,+1,-1,-1,-1,-1,+1,+1,-1,-1,-1,+1,-1,-1,-1,+1,+1,-1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,-1,-1,-1,+1,-1,-1,-1,-1,-1, -1,-1,-1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,0,-1,+1,-1,-1,+1,+1,+1, -1,-1,+1,+1,-1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,+1,-1,+1,+1,+1,+1,-1,+1,+1,+1,+1, ,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1}, and also includes the sequence obtained by flipping the polarity of each value of the sequence (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0, that is, null subcarriers. Here, -500:4:500 means -500, -496, …, -8, -4, 0, 4, 8, …, 496, 500. At this time, the corresponding pilot subcarrier positions are ±24, ±92, ±400, ±468, that is, there are 8 pilot subcarriers.In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.8609dB. In the case of multiple spatial streams, the PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier is only 0.1413dB, and the worst PAPR value is 5.0022dB. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols at 80MHz bandwidth are greater than 6dB in the worst case. It should be noted here that the optimal here refers to the left and right parts of the sequence that can be combined to form a set of 160M 1x HE-LTF sequences with excellent performance.

[0136]

[0137] Preferably, the preferred sequence is: HE-LTF 250 (-500:4:500)={+1,-1,-1,+1,-1,+1,+1,-1,LTF left ,LTF right ,+1,+1,-1,+1,+1,-1,-1,-1,LTF left ,-1*LTF right ,+1,-1,-1,-1,-1,0,+1,+1,+1,-1,-1,LTF left ,LTF right ,-1,+1,+1,+1,+1,-1,+1,-1,-1*LTF left ,LTF right ,+1,+1,+1,+1,-1,-1,-1,+1}, which can also be expressed as HE-LTF 250(-500:4:500)={+1,-1,-1,+1,-1,+1,+1,-1,+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1, +1,-1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,0,+1,+1,+1,-1,-1,+1,+1, -1,-1,+1,+1,-1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,-1,-1,-1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1 Here, -500:4:500 means -500, -496, ..., -8, -4, 0, 4, 8, ..., 496, 500. At this time, the corresponding pilot subcarrier positions are ±24, ±92, ±400, ±468, that is, there are 8 pilot subcarriers.

[0138] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.8024 dB.

[0139] Refer to Table 11, which lists the PAPR values ​​caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams. The PAPR oscillation caused by the phase difference between the data subcarrier and the pilot subcarrier when there are multiple spatial streams is only 0.1324dB, and the worst PAPR value is 4.9348dB. The PAPR values ​​of the existing 4x HE-LTF symbols and 2x HE-LTF symbols in 80MHz bandwidth are greater than 6dB in the worst case.

[0140]

[0141] Table 11

[0142] Suboptimal, sequence: HE-LTF 250 (-500:4:500)={-1,+1,+1,+1,-1,+1,+1,+1,-1*LTF left ,-1*LTF right ,+1,-1,-1,-1,-1,-1,+1,+1,LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,+0,+1,-1,+1,+1,+1,-1*LTF left ,-1*LTF right ,+1,-1,+1,+1,-1,-1,+1,-1,-1*LTF left ,LTF right ,-1,+1,+1,+1,+1,-1,-1,-1}, which can also be expressed as HE-LTF 250(-500:4:500) = {-1,+1,+1,+1,-1,+1,+1,+1,-1,-1,+1,+1,+1,-1,-1,+1,+1,-1,-1,-1,-1,-1,-1,+1,+1,-1,-1,-1,-1,+1,+1,-1,-1,-1,+1,-1,-1,-1,+1,+1,-1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,-1,-1,+1,-1,-1,-1,-1,-1,+1,-1,-1,-1,-1,-1,-1,+1,-1,-1,-1,-1,-1,-1, -1,-1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,+0,+1,-1,+1,+1,+1,-1,-1,-1 ,+1,+1,-1,-1,+1,-1,-1,-1,-1,-1,-1,-1,+1,+1,-1,-1,-1,+1,-1,-1,-1,+1,+1,-1,-1,-1,+1,+1,-1,-1,+ ... The subcarriers are 0, i.e., null subcarriers.

[0143] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.97 dB.

[0144] Table 12 lists the PAPR values ​​caused by the phase difference between data subcarriers and pilot subcarriers when there are multiple spatial streams. The PAPR oscillation caused by the phase difference between data subcarriers and pilot subcarriers when there are multiple spatial streams is only 0.26 dB, and the worst PAPR value is 4.97 dB.

[0145]

[0146] Table 12

[0147] Again, the best sequence is: HE-LTF 250 (-500:4:500)={-1,-1,-1,+1,+1,+1,+1,+1,-1*LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,-1,-1,-1,LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,+0,-1,+1,+1,-1,-1,LTF left ,LTF right ,-1,+1,-1,-1,+1,-1,-1,+1,LTF left ,-1*LTF right ,+1,-1,+1,-1,-1,-1,+1,+1}, which can also be expressed as HE-LTF 250(-500:4:500)={-1,-1,-1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,+1,-1,-1,+1,-1,-1,-1,-1,-1,-1,+1,+1,-1,-1,-1,-1,+1,-1,+1,-1,-1,-1,+1,-1,-1,+1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1,-1,+1,-1, -1,-1,-1,-1,+1,+1,-1,-1,+1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,-1,+1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+0,-1,+1,+1,-1,-1,+1,+1 ,-1,-1,+1,+1,-1,+1,+1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,-1,+1,+1,+1,+1,-1,-1,+1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,-1,+1,+1,+1,+1,-1,+1,+1,+1,+1,-1,+1,+1,+1,+1,+1,-1,+1,+1,+1,+1, The subcarriers in the sequence are: 1,+1,+1,+1,+1,-1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1,-1,+1,+1,-1,+1,-1,+1,+1,-1,+1,-1,+1,-1,+1,-1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,-1,+1,+1}, and also includes the sequence after every value of the sequence is reversed in polarity (that is, +1 becomes -1, -1 becomes +1, and 0 remains unchanged), and the rest of the subcarriers are 0, that is, null subcarriers.

[0148] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 4.53 dB.

[0149] Table 13 lists the PAPR values ​​caused by the phase difference between data subcarriers and pilot subcarriers when there are multiple spatial streams. The PAPR oscillation caused by the phase difference between data subcarriers and pilot subcarriers when there are multiple spatial streams is only 0.52 dB, and the worst PAPR value is 5.05 dB.

[0150]

[0151] Table 13

[0152] Embodiment 5 of the present invention

[0153] 160MHz bandwidth solution 1:

[0154] The subcarrier design of 160MHz bandwidth can be obtained by splicing two 80MHz subcarrier designs. The main 80M band and the auxiliary 80M band can be continuously spliced ​​or spaced at a certain bandwidth (for example, 100MHz). In addition, the front and back positions of the main 80M band and the auxiliary 80M band can be flexibly adjusted according to actual conditions. Therefore, we can define the 1x HE-LTF sequence of the main 80M band and the auxiliary 80M band respectively, and flexibly adjust the polarity of the 80M sequence as a whole according to the interval and the order of the bands to obtain a lower PAPR. Here, let the optimal sequence in the fourth embodiment of the present invention be represented as HE-LTF 80M_A , and HE-LTF 80M_A (-500:4:500) = {L-LTF 80M_A ,0,R-LTF 80M_A}. We use the sequence L-LTF 80M_A Medium R-LTF 80M_A As the basic sequence, the main 80M sequence and the auxiliary 80M sequence are generated respectively. Among them, the main 80M 1x HE-LTF sequence is LTF 80M_Primary ={L-LTF 80M_A ,0,R-LTF 80M_A}, auxiliary 80M 1x HE-LTF sequence is LTF 80M_Secondary ={L-LTF 80M_A ,0,-1*R-LTF 80M_A}.

[0155] For the convenience of description, let P1 represent the polarity adjustment coefficient of the main 80M sequence, and P2 represent the polarity adjustment coefficient of the auxiliary 80M sequence. We fix P1 to +1, and P2 can be +1 or -1. When the placement relationship of the two 80M channels is [main 80M, auxiliary 80M], the 160M sequence is: HE-LTF 500 =[P1*LTF 80M_Primary ,BI,P2*LTF 80M_Secondary]; When the placement relationship of the two 80M channels is [auxiliary 80M, primary 80M], the 160M sequence is: HE-LTF 500 =[P2*LTF 80M_Secondary ,BI,P1*LTF 80M_Primary ]. Among them, BI refers to the frequency interval between the edge subcarriers of two 80M channels. When the primary 80M and secondary 80M channels are adjacent, BI = {0,0,0,0,0}; when the primary 80M and secondary 80M channels are not adjacent, BI can be adjusted accordingly; at the same time, the primary 80M and secondary 80M can be generated independently and then spliced ​​into a 160M frequency band.

[0156] The polarity adjustment coefficients of the main 80MHz bandwidth and the auxiliary 80MHz bandwidth in the order of the two frequency bands and various frequency intervals are shown in the following table, where the main and auxiliary channel intervals refer to the center frequency intervals of the two 80M frequency bands (the interval of 80MHz refers to the splicing of two adjacent 80M channels). The corresponding PAPR values ​​in various cases are also specifically shown in the table, where the PAPR value is the maximum value under the four phase differences between data and pilot. As can be seen from the table below, only in a few cases do the main and auxiliary 80M bandwidth sequences require polarity adjustment, and in most other cases they can be directly spliced. For example, when the placement relationship of two adjacent 80M channels is [main 80M, auxiliary 80M], the 160M sequence is specifically HE-LTF 500 (-1012:4:1012) = {L-LTF 80M_A ,0,R-LTF 80M_A ,0,0,0,0,0,L-LTF 80M_A ,0,-1*R-LTF 80M_A}.

[0157]

[0158]

[0159] In addition, in order to reduce the complexity of system implementation, it is also possible to sacrifice a certain PAPR performance and directly concatenate the main 80M sequence and the auxiliary 80M sequence to obtain a 1x HE-LTF sequence under 160M bandwidth in various cases.

[0160] Solution 2 for 160MHz bandwidth:

[0161] Since the subcarrier design of 160MHz bandwidth is to repeat the subcarrier design of 80MHz and directly splice it, the 1x HE-LTF sequence under 160M bandwidth is generated based on the 1x HE-LTF better sequence under 80M bandwidth described in Example 4. For the convenience of description, we call this better sequence HE-LTF 80M , and HE-LTF 80M(-500:4:500) = {L-LTF 80M ,0,R-LTF 80M}. The following sequence for the 160MHz bandwidth solution is: HE-LTF 500 (-1012:4:1012) = {L-LTF 80M ,0,R-LTF 80M ,0,0,0,0,0,-1*L-LTF 80M ,0,R-LTF 80M}, the remaining subcarriers are 0, that is, null subcarriers. Here, -1012:4:1012 means -1012, -1008, ..., -8, -4, 0, 4, 8, ..., 1008, 1012. At this time, the corresponding pilot subcarrier positions are ±44, ±112, ±420, ±488 ±536, ±604, ±912, ±980, that is, there are 16 pilot subcarriers.

[0162] In the case of a single spatial stream, the PAPR value of the 1x HE-LTF symbol generated according to the sequence is only 5.7413 dB.

[0163] Table 14 lists the PAPR values ​​caused by the phase difference between data subcarriers and pilot subcarriers when there are multiple spatial streams. When there are multiple spatial streams, the PAPR oscillation caused by the phase difference between data subcarriers and pilot subcarriers is 0.3948 dB, and the worst PAPR value is only 5.9667 dB.

[0164]

[0165] Table 14

[0166] Another solution with 160MHz bandwidth:

[0167] The subcarrier design of 160MHz bandwidth can be obtained by splicing two 80MHz subcarrier designs. The main 80M band and the auxiliary 80M band can be spliced ​​continuously or separated by a certain bandwidth (for example, 100MHz). In addition, the front and back positions of the main 80M band and the auxiliary 80M band can be flexibly adjusted according to actual conditions. Therefore, we can define the 1x HE-LTF sequence of the main 80M band and the auxiliary 80M band respectively, and flexibly adjust the polarity of the 80M sequence as a whole according to their interval and the order of the bands to obtain a lower PAPR.

[0168] Here, we use the suboptimal sequence and the third optimal sequence in Embodiment 4 of the present invention as the main 80M sequence and the auxiliary 80M sequence respectively, and concatenate them to obtain a new 1x HE-LTF sequence under a 160MHz bandwidth.

[0169] For the convenience of description, we call the suboptimal sequence in the fourth embodiment of the present invention LTF 80M_Primary The re-optimized sequence in the fourth embodiment of the present invention is called LTF 80M_Secondary Let P1 represent the polarity adjustment coefficient of the main 80M sequence, and P2 represent the polarity adjustment coefficient of the auxiliary 80M sequence. We fix P1 to +1, and P2 can be +1 or -1. When the placement relationship of the two 80M channels is [main 80M, auxiliary 80M], the 160M sequence is: HE-LTF 500 =[P1*LTF 80M_Primary ,BI,P2*LTF 80M_Secondary ]; When the placement relationship of the two 80M channels is [auxiliary 80M, primary 80M], the 160M sequence is: HE-LTF 500 =[P2*LTF 80M_Secondary ,BI,P1*LTF 80M_Primary ]. Among them, BI refers to the frequency interval between the edge subcarriers of two 80M channels. When the primary 80M and secondary 80M channels are adjacent, BI = {0,0,0,0,0}; when the primary 80M and secondary 80M channels are not adjacent, BI can be adjusted accordingly; at the same time, the primary 80M and secondary 80M can be generated independently and then spliced ​​into a 160M frequency band.

[0170] The polarity adjustment coefficients of the main 80MHz bandwidth and the auxiliary 80MHz bandwidth in the order of the two frequency bands and various frequency intervals are shown in Table 15 below, where the main and auxiliary channel intervals refer to the center frequency intervals of the two 80M frequency bands (the interval of 80MHz refers to the splicing of two adjacent 80M channels).

[0171] The corresponding PAPR values ​​in various cases are also shown in Table 15, where the PAPR value is the maximum value under the four phase differences between data and pilot. As can be seen from the table below, only in a few cases do the primary and secondary 80M bandwidth sequences need polarity adjustment, and in most other cases they can be directly spliced.

[0172]

[0173]

[0174] Table 15

[0175] In addition, in order to reduce the complexity of system implementation, it is also possible to sacrifice a certain PAPR performance and directly concatenate the main 80M sequence and the auxiliary 80M sequence to obtain a 1x HE-LTF sequence under 160M bandwidth in various cases.

[0176] In each embodiment of the present invention, the 1xHE-LTF sequence has good PAPR characteristics under different bandwidths, and the PAPR characteristic fluctuation is very small when there are multiple spatial streams. The power amplifier can be effectively utilized, and the power can be better enhanced in the long-distance transmission mode to adapt to longer-distance transmission.

[0177] The present invention can be applied to wireless local area networks, including but not limited to Wi-Fi systems represented by 802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac, and can also be applied to next-generation Wi-Fi systems and next-generation wireless local area network systems.

[0178] The present invention also provides a data transmission device capable of executing the above method. Fig.11 This is an example of a structural schematic diagram of a data transmission device provided in an embodiment of the present invention (for example, some devices in the diagram such as an access point, a station, or a chip are optional). Fig.11 As shown, the data transmission device 1200 can be implemented by a bus 1201 as a general bus architecture. According to the specific application and overall design constraints of the data transmission device 1200, the bus 1201 can include any number of interconnected buses and bridges. The bus 1201 connects various circuits together, including a processor 1202, a storage medium 1203 and a bus interface 1204. The data transmission device 1200 uses the bus interface 1204 to connect a network adapter 1205 and the like via the bus 1201. The network adapter 1205 can be used to implement the signal processing function of the physical layer in the wireless local area network, and to transmit and receive radio frequency signals through the antenna 1207. The user interface 1206 can be connected to a user terminal, such as a keyboard, a display, a mouse, a joystick, etc. The bus 1201 can also be connected to various other circuits, such as a timing source, a peripheral device, a voltage regulator, a power management circuit, etc. These circuits are well known in the art and are therefore not described in detail.

[0179] The data transfer device 1200 can also be configured as a general-purpose processing system that includes: one or more microprocessors that provide processor functions; and an external memory that provides at least a portion of the storage medium 1203, all of which are connected together with other supporting circuits through an external bus architecture.

[0180] Alternatively, the data transmission device 1200 may be implemented using: an ASIC (application-specific integrated circuit) having a processor 1202, a bus interface 1204, a user interface 1206; and at least a portion of a storage medium 1203 integrated in a single chip, or the data transmission device 1200 may be implemented using: one or more FPGAs (field programmable gate arrays), PLDs (programmable logic devices), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout the present invention.

[0181] Processor 1202 is responsible for managing the bus and general processing (including executing software stored on storage medium 1203). Processor 1202 can be implemented using one or more general-purpose processors and / or special-purpose processors. Examples of processors include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Software should be broadly interpreted as representing instructions, data, or any combination thereof, regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0182] exist Fig.11 The storage medium 1203 is shown as being separated from the processor 1202, however, it is readily apparent to those skilled in the art that the storage medium 1203 or any portion thereof may be located outside the data transmission device 1200. For example, the storage medium 1203 may include a transmission line, a carrier waveform modulated with data, and / or a computer product separated from a wireless node, all of which may be accessed by the processor 1202 through the bus interface 1204. Alternatively, the storage medium 1203 or any portion thereof may be integrated into the processor 1202, for example, may be a cache and / or a general register.

[0183] The processor 1202 can execute the above embodiments, which will not be described in detail here.

[0184] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

Claims

1. A channel estimation method, characterized in that: include: The LTF frequency domain sequence is determined by the transmission bandwidth and the LTF mode; According to the number of OFDM symbols N contained in the LTF field HELTF and the determined LTF frequency domain sequence, sending an LTF time domain signal; The LTF frequency domain sequence of the 1x mode of the transmission bandwidth includes at least one of the following sequence segments, and the sequence segments include: L-LTF 80M_A , R-LTF 80M_A , -1*L-LTF 80M_A , -1*R-LTF 80M_A ; Wherein, the L-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,–1,+1,+1,+1,+1,–1,–1,–1,+1,+1,–1,–1,+1,–1,–1,–1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,–1,+1 1,+1,–1,–1,–1,–1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1}; The R-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,+1,+1,–1,–1,+1,+1,–1,+1,–1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,– ... 1,–1,+1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,+1}.

2. The method according to claim 1, characterized in that The L-LTF 80M_A The value of the remaining subcarriers is 0. 80M_A The value on the remaining subcarriers is 0.

3. The method according to claim 2, characterized in that The transmission bandwidth is 80 MHz bandwidth, and the LTF frequency domain sequence of the 1x mode of the 80 MHz bandwidth includes {L-LTF 80M_A ,0,R-LTF 80M_A }.

4. The method according to claim 2, characterized in that: The transmission bandwidth is 160 MHz bandwidth, and the LTF frequency domain sequence of the 1x mode of the 160 MHz bandwidth also includes a BI sequence segment, and the BI sequence segment is all zeros.

5. The method according to claim 4, characterized in that The LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,L-LTF 80M_A ,0,-1*R-LTF 80M_A }.

6. The method according to claim 4, characterized in that The LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,-1*L-LTF 80M_A ,0,R-LTF 80M_A }.

7. The method according to any one of claims 1 to 6, characterized in that: When the LTF time domain signal is located in an uplink multi-user multiple input multiple output (UL-MU-MIMO) data packet, the method further includes: Before sending the UL-MU-MIMO data packet, a trigger frame is received, where the trigger frame is used to indicate uplink scheduling information, where the uplink scheduling information at least includes an identifier of the scheduled site, the transmission bandwidth, and the number N of OFDM symbols included in the LTF field. HELTF .

8. The method according to any one of claims 1 to 6, characterized in that: When the LTF time domain signal is located in a single user (SU) data packet, the method further includes: From the total number of space-time flows N STS Determine the number N of OFDM symbols contained in the LTF domain HELTF ; Among them, the N STS and the N HELTF The corresponding relationship is as follows: 。 9. A channel estimation method, characterized in that: include: Receiving an LTF time domain signal, wherein the LTF time domain signal carries an LTF frequency domain sequence; Obtaining a channel estimation value corresponding to a subcarrier position from the received LTF frequency domain sequence and a known LTF frequency domain sequence; The known LTF frequency domain sequence of the 1x mode of the transmission bandwidth includes at least one of the following sequence segments, wherein the sequence segment includes: L-LTF 80M_A , R-LTF 80M_A , -1*L-LTF 80M_A , -1*R-LTF 80M_A ; Wherein, the L-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,–1,+1,+1,+1,+1,–1,–1,–1,+1,+1,–1,–1,+1,–1,–1,–1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,–1,+1 1,+1,–1,–1,–1,–1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1}; The R-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,+1,+1,–1,–1,+1,+1,–1,+1,–1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,– ... 1,–1,+1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,+1}.

10. The method according to claim 9, characterized in that The L-LTF 80M_A The value of the remaining subcarriers is 0. 80M_A The value on the remaining subcarriers is 0.

11. The method according to claim 10, characterized in that The transmission bandwidth is 80 MHz bandwidth, and the known LTF frequency domain sequence of the 1x mode of the 80 MHz bandwidth includes {L-LTF 80M_A ,0,R-LTF 80M_A }.

12. The method according to claim 10, characterized in that The transmission bandwidth is 160 MHz bandwidth, and the known LTF frequency domain sequence of the 1x mode of the 160 MHz bandwidth also includes a BI sequence segment, and the BI sequence segment is all zeros.

13. The method according to claim 12, characterized in that The known LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,L-LTF 80M_A ,0,-1*R-LTF 80M_A }.

14. The method according to claim 12, characterized in that The known LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,-1*L-LTF 80M_A ,0,R-LTF 80M_A }.

15. The method according to any one of claims 9 to 14, characterized in that: When the LTF time domain signal is located in an uplink multi-user multiple input multiple output (UL-MU-MIMO) data packet, the method further includes: Before receiving the UL-MU-MIMO data packet, a trigger frame is sent, where the trigger frame is used to indicate uplink scheduling information, where the uplink scheduling information at least includes an identifier of the scheduled site, the transmission bandwidth, and the number N of OFDM symbols included in the LTF field. HELTF .

16. The method according to any one of claims 9 to 14, characterized in that: When the LTF time domain signal is located in a single user (SU) data packet, the method further includes: According to the information carried by the signaling field in the preamble of the SU data packet, the transmission bandwidth and the total number of space-time streams N are obtained. STS , and LTF mode; The total number of space-time flows N STS Determine the number of OFDM symbols N contained in the LTF field HELTF ; The known LTF frequency domain sequence is determined by the transmission bandwidth and the LTF mode.

17. The method according to claim 16, characterized in that The total number of space-time flows N STS Determine the number N of OFDM symbols contained in the LTF domain HELTF , the N STS and the N HELTF The corresponding relationship is as follows: 。 18. A channel estimation device, characterized in that: include: A processing unit, configured to determine an LTF frequency domain sequence according to a transmission bandwidth and an LTF mode; The sending unit is used to send the OFDM symbol number N contained in the LTF field. HELTF and the determined LTF frequency domain sequence, sending an LTF time domain signal; The LTF frequency domain sequence of the 1x mode of the transmission bandwidth includes at least one of the following sequence segments, and the sequence segments include: L-LTF 80M_A , R-LTF 80M_A , -1*L-LTF 80M_A , -1*R-LTF 80M_A ; Wherein, the L-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,–1,+1,+1,+1,+1,–1,–1,–1,+1,+1,–1,–1,+1,–1,–1,–1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,–1,+1 1,+1,–1,–1,–1,–1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1}; The R-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,+1,+1,–1,–1,+1,+1,–1,+1,–1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,– ... 1,–1,+1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,+1}.

19. The device according to claim 18, characterized in that The L-LTF 80M_A The value of the remaining subcarriers is 0. 80M_A The value on the remaining subcarriers is 0.

20. The device according to claim 19, characterized in that The transmission bandwidth is 80 MHz bandwidth, and the LTF frequency domain sequence of the 1x mode of the 80 MHz bandwidth includes {L-LTF 80M_A ,0,R-LTF 80M_A }.

21. The device according to claim 19, characterized in that The transmission bandwidth is 160 MHz bandwidth, and the LTF frequency domain sequence of the 1x mode of the 160 MHz bandwidth also includes a BI sequence segment, and the BI sequence segment is all zeros.

22. The device according to claim 21, characterized in that The LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,L-LTF 80M_A ,0,-1*R-LTF 80M_A }.

23. The device according to claim 21, characterized in that The LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,-1*L-LTF 80M_A ,0,R-LTF 80M_A }.

24. The device according to any one of claims 18 to 23, characterized in that When the LTF time domain signal is located in an uplink multi-user multiple input multiple output (UL-MU-MIMO) data packet, the apparatus further includes: A receiving unit, configured to receive a trigger frame before sending the UL-MU-MIMO data packet, wherein the trigger frame is used to indicate uplink scheduling information, wherein the uplink scheduling information at least includes an identifier of a scheduled site, the transmission bandwidth, and the number N of OFDM symbols included in the LTF field. HELTF .

25. The device according to any one of claims 18 to 23, characterized in that When the LTF time domain signal is located in a single user (SU) data packet, the processing unit is further configured to: STS Determine the number N of OFDM symbols contained in the LTF domain HELTF ; wherein the N STS and the N HELTF The corresponding relationship is as follows: 。 26. A channel estimation device, characterized in that: include: A receiving unit, configured to receive an LTF time domain signal, wherein the LTF time domain signal carries an LTF frequency domain sequence; A processing unit, configured to obtain a channel estimation value corresponding to a subcarrier position from the received LTF frequency domain sequence and a known LTF frequency domain sequence; The known LTF frequency domain sequence of the 1x mode of the transmission bandwidth includes at least one of the following sequence segments, wherein the sequence segment includes: L-LTF 80M_A , R-LTF 80M_A , -1*L-LTF 80M_A , -1*R-LTF 80M_A ; Wherein, the L-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,–1,+1,+1,+1,+1,–1,–1,–1,+1,+1,–1,–1,+1,–1,–1,–1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,–1,–1,+1,+1,–1,–1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,–1,+1,–1,+1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,+1,–1,–1,–1,–1,+1 1,+1,–1,–1,–1,–1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,+1,–1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1}; The R-LTF 80M_A The values ​​at every 4th subcarrier index are {–1,+1,+1,–1,–1,+1,+1,–1,+1,–1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,– ... 1,–1,+1,–1,–1,+1,+1,+1,–1,–1,+1,+1,+1,–1,+1,+1,+1,+1,+1,–1,–1,+1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,–1,+1,+1}.

27. The device according to claim 26, characterized in that The L-LTF 80M_A The value of the remaining subcarriers is 0. 80M_A The value on the remaining subcarriers is 0.

28. The device according to claim 27, characterized in that The transmission bandwidth is 80 MHz bandwidth, and the known LTF frequency domain sequence of the 1x mode of the 80 MHz bandwidth includes {L-LTF 80M_A ,0,R-LTF 80M_A }.

29. The device according to claim 27, characterized in that The transmission bandwidth is 160 MHz bandwidth, and the known LTF frequency domain sequence of the 1x mode of the 160 MHz bandwidth also includes a BI sequence segment, and the BI sequence segment is all zeros.

30. The device according to claim 29, characterized in that The known LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,L-LTF 80M_A ,0,-1*R-LTF 80M_A }.

31. The device according to claim 29, characterized in that The known LTF frequency domain sequence of the 1x mode with a bandwidth of 160 MHz includes {L-LTF 80M_A ,0,R-LTF 80M_A , BI,-1*L-LTF 80M_A ,0,R-LTF 80M_A }.

32. The device according to any one of claims 26 to 31, characterized in that When the LTF time domain signal is located in an uplink multi-user multiple input multiple output (UL-MU-MIMO) data packet, the apparatus further includes: A sending unit, configured to send a trigger frame before receiving the UL-MU-MIMO data packet, wherein the trigger frame is used to indicate uplink scheduling information, wherein the uplink scheduling information at least includes an identifier of the scheduled site, the transmission bandwidth, and the number N of OFDM symbols included in the LTF field. HELTF .

33. The device according to any one of claims 26 to 31, characterized in that When the LTF time domain signal is located in a single user (SU) data packet, the processing unit is further configured to: According to the information carried by the signaling field in the preamble of the SU data packet, the transmission bandwidth and the total number of space-time streams N are obtained. STS , and LTF mode; The total number of space-time flows N STS Determine the number of OFDM symbols N contained in the LTF field HELTF ; The known LTF frequency domain sequence is determined by the transmission bandwidth and the LTF mode.

34. The device according to claim 33, characterized in that The total number of space-time flows N STS Determine the number of OFDM symbols N contained in the LTF field HELTF , the N STS and the N HELTF The corresponding relationship is as follows: 。

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