A channel estimation method and signal receiving method based on subcarrier sequence for channel impulse response and

Abstract

A channel estimation method and a signal receiving method based on a subcarrier sequence for channel impulse response and channel estimation, and relate to the field of communication technology, and in particular to the field of signal processing. The invention solves the problem that the existing channel estimation and compensation methods increase the difficulty of channel compensation while improving the accuracy, and the accuracy is affected by a certain error caused by the precision estimation. The channel estimation method described in the present invention utilizes the full-band coverage and ideal autocorrelation characteristics of the subcarrier sequence to perform cyclic convolution summation, and estimates the channel impulse response and channel of multiple parallel transmission symbols passing through the channel. The pilot is a selected subcarrier, which is transmitted simultaneously with the data subcarrier and experiences the same channel state, effectively reducing the influence of the channel time-varying property on the channel estimation, and there is no need to accurately distinguish the channel multipath and its channel gain. The present invention is applied to a receiver method in an application scenario in the field of signal processing using a multiple parallel transmission system.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to the field of signal processing. Background Art

[0002] Existing channel estimation methods can be roughly divided into three types. One is carried out in the frequency domain to accurately estimate the fading of the channel at each frequency point for signal compensation; another is carried out in the time domain to accurately estimate the time-domain channel impulse response and then perform subsequent channel equalization; and there is also a channel estimation method based on basis expansion, which obtains channel information by accurately estimating basis expansion coefficients. For channel compensation, there is a method of performing channel equalization after obtaining accurate channel information using channel estimation, and there is also the commonly used RAKE receiver in the spread-spectrum transmission system. The RAKE receiver uses sliding correlation to estimate each delay multipath of the channel and its channel gain, and then performs corresponding channel compensation on the signal.

[0003] These several channel estimation and channel compensation methods are all accurate estimations of channel information. Whether it is the estimation of each frequency point or the separation and gain estimation of each delay path, this will increase the difficulty of channel estimation and channel compensation, and accurate estimation will bring certain errors, greatly reducing the accuracy. Summary of the Invention

[0004] The object of the present invention is to solve the problems that the existing channel estimation and compensation methods increase the difficulty of channel compensation while improving the accuracy, and due to the accuracy estimation, certain errors are generated, which in turn affect the accuracy.

[0005] To achieve the above object, the present invention provides the following solution:

[0006] A channel estimation method for the sum of channel impulse responses based on subcarrier sequences, the method comprising:

[0007] Step of selecting subcarrier spacing: Select the subcarrier spacing as L for a channel where the maximum tap of the channel delay is less than L;

[0008] Step of calculating the number of subcarrier times: There are N subcarrier sequences for subcarrier cyclic shift, which are ψ0(n), ψ1(n), ψ2(n),..., ψ n (n), the number of loaded subcarriers is k, k = [N / L], [] represents rounding down;

[0009] Step of selecting data transmission: The subcarrier sequences for data transmission are ψ i (n), ψ i+L (n), ψ i+2L (n),... ψ i+kL (n), i < L, and a total of k data are transmitted, and the transmitted data sequence is XN×1 =[x(0),0,...,0,x(1),0,...,x(k)] T ;

[0010] Steps for selecting pilot subcarriers: The pilot subcarrier used for channel estimation is ψ i (n), the data transmitted by the selected subcarrier is x(0);

[0011] The step of generating transmission symbols: the subcarrier sequence of the data transmission is multiplied by the data transmitted by the subcarrier, and all modulated subcarrier sequences are added to form a new sequence, which is the transmission symbol;

[0012] Step of receiving symbols: the transmission symbol is sent to the channel, attenuated by the channel, superimposed with channel noise, and reaches the receiving end. The transmission symbol received by the receiving end is the receiving symbol;

[0013] Step of calculating the channel estimation value: the received symbol and the subcarrier ψ i (n) performing a cyclic correlation calculation at point L, summing the sequence of the cyclic correlation calculations at point L, dividing the sum by the data x(0) transmitted by the subcarrier, and obtaining a channel impulse response and a channel estimation value of each subcarrier passing through the channel.

[0014] Furthermore, in a preferred embodiment, the subcarrier sequence is a sequence having a ZC sequence property and a cyclic shift characteristic.

[0015] Furthermore, in another preferred embodiment, the cyclic correlation calculation of the above-mentioned point L is:

[0016] The received symbol is a sequence a = [a(0), a(1), ..., a(N-1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1), ..., b(N-1)]. A circular correlation operation of L points is performed on sequence a and sequence b, and the result is an L-point long sequence c = [c(0), c(1), ..., c(L-1)].

[0017] Corresponding to the above method, the present invention also provides a channel estimation system based on a subcarrier sequence for performing a channel impulse response and a channel estimation, the system comprising:

[0018] Device for selecting subcarrier spacing: a storage device for selecting a subcarrier spacing of L, for a channel with a maximum channel delay tap less than L;

[0019] The device for calculating the number of subcarriers is used to calculate the total number of N subcarrier sequences according to the subcarrier cyclic shift, which are ψ0(n), ψ1(n), ψ2(n), ..., ψ n(n), a storage device that obtains the number of subcarriers of the load as k, where k = [N / L], and [] represents rounding down;

[0020] Device for selecting data transmission: for the subcarrier sequence ψ i (n), ψ i+L (n), ψ i+2L (n),...ψ i+kL (n), i < L, and a total of k data are transmitted. The selected data sequence for transmission is X N×1 = [x(0), 0,..., 0, x(1), 0,..., x(k)] T of the storage device;

[0021] Device for selecting pilot subcarriers: the pilot subcarriers for channel estimation are ψ i (n), a storage device that selects the data transmitted on the subcarrier as x(0)

[0022] Device for generating transmission symbols: a storage device that multiplies the subcarrier sequence for data transmission by the data sequence transmitted on the subcarrier, adds the resulting sequences to obtain a new sequence, and the new sequence is the transmission symbol;

[0023] Device for receiving symbols: a storage device that sends the transmission symbol to the channel, after channel attenuation and superposition of channel noise, reaches the receiving end, and the transmission symbol received at the receiving end is the received symbol;

[0024] Device for calculating the channel estimation value: for performing L-point circular correlation calculation on the received symbol and the subcarrier ψ i (n), summing the sequence of the L-point circular correlation calculation, and dividing the sum value of the summation by the data x(0) transmitted on the subcarrier to obtain the channel estimation value of the channel impulse response sum of the subcarrier passing through the channel.

[0025] Furthermore, there is also a preferred embodiment. The above subcarrier sequence is a sequence with ZC sequence properties and cyclic shift characteristics.

[0026] Furthermore, there is also a preferred embodiment. The above L-point circular correlation calculation is as follows:

[0027] The received symbol is the sequence a = [a(0), a(1),..., a(N - 1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1),..., b(N - 1)]. Perform L-point circular correlation operation on the sequence a and the sequence b, and the resulting result is a sequence c = [c(0), c(1),..., c(L - 1)] with a length of L points.

[0028] Based on the above method, the present invention also provides a computer device, which includes a memory and a processor, wherein a computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes any one of the channel estimation methods based on subcarrier sequence and channel impulse response described in the present invention.

[0029] The present invention also provides a receiving method for channel estimation of a multi-path parallel transmission system based on a subcarrier sequence, the method is implemented based on the above-mentioned channel estimation method for channel impulse response and based on a subcarrier sequence, the method comprising: receiving a signal, removing a cyclic prefix from the signal and dividing it into two paths:

[0030] The channel estimation method of the present invention is used to perform channel estimation to obtain a channel impulse response and a channel estimation value;

[0031] The other data is respectively connected to the transmission data subcarrier sequence ψ stored at the receiving end i (n), ψ i+L (n), ψ i+2L (n), ..., ψ i+kL An L-point cyclic correlation calculation is performed on each subcarrier in (n). After the sequence obtained by each L-point cyclic correlation calculation is summed, it is divided by the obtained channel estimation value to obtain the data information transmitted on each subcarrier after recovery. The data of all the obtained subcarriers are digitally demodulated to restore the information sequence.

[0032] Technical Effects

[0033] The channel estimation method described in the present invention utilizes the full-band coverage and ideal autocorrelation characteristics of the subcarrier sequence, and estimates the channel and subsequently performs channel compensation on the signal when the subcarrier is transmitted in a multi-path parallel transmission system generated by cyclic shift. Different from the prior art, the present invention only needs to estimate the channel impulse response and does not need to accurately distinguish the channel multipath and its channel gain, which can reduce the difficulty of accurate channel estimation and reduce the error caused by accurate estimation.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. The existing channel equalization estimation methods all make accurate estimates of the channel state information to see the impact of the channel state on each point of the signal, whether it is the estimation of each frequency point or the separation and gain estimation of each delay path. The channel estimation method based on the subcarrier sequence for channel impulse response and the ideal autocorrelation characteristics of the subcarrier sequence are used to perform circular convolution summation, and the channel impulse response and of the multi-path parallel transmission symbols through the channel are estimated. The pilot is a selected subcarrier, which is transmitted simultaneously with the data subcarrier and experiences the same channel state, which can effectively reduce the impact of the channel time variability on the channel estimation. When the maximum delay tap of the channel is less than the subcarrier spacing, the channel information summation estimation can be performed on the channel through which the signal passes. There is no need to accurately distinguish the channel multipath and its channel gain, which can reduce the difficulty of accurate channel estimation and the error caused by accurate estimation.

[0036] 2. The receiving method described in the present invention is different from the receiving method of the RAKE receiver commonly used in the spread spectrum transmission system in the prior art. The existing commonly used RAKE receiver needs to accurately estimate each delay path in the multipath channel and needs to accurately separate each delay path, which increases the difficulty of channel estimation when there are many multipaths. However, the present invention only needs to estimate the impulse response of the entire channel, and does not need to separate each delay multipath. Under the condition of ensuring the integrity of the channel information, the difficulty of channel estimation and the error caused by accurate estimation are reduced.

[0037] 3. The channel estimation method described in the present invention utilizes the full-band coverage and ideal autocorrelation characteristics of the subcarrier sequence, which is completely different from the principles of the existing channel estimation methods. It innovatively proposes a method for channel estimation by performing cyclic correlation summation on the sequence, and proposes a receiving method for channel estimation of a multi-channel parallel transmission system based on the subcarrier sequence.

[0038] The present invention is applied to a receiver method in an application scenario using a multi-path parallel transmission system in the field of signal processing or the field of communication technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a signal modulation block diagram of an underloaded multi-channel parallel transmission system in a channel impulse response and channel estimation method based on a subcarrier sequence as described in Implementation Method 2.

[0040] Figure 2 It is a schematic diagram of a multi-channel parallel transmission transmitting end system in a receiving method for channel estimation of a multi-channel parallel transmission system based on a subcarrier sequence as described in Implementation Example 8.

[0041] Figure 3 It is a schematic diagram of a multi-channel parallel transmission receiving end system in a receiving method for channel estimation of a multi-channel parallel transmission system based on a subcarrier sequence as described in Implementation Example 8.

[0042] Figure 4 It is the subcarrier chirp signal channel estimation amplitude diagram described in Embodiment 9.

[0043] Figure 5 It is the subcarrier chirp signal channel estimation phase value diagram described in Embodiment 9.

[0044] Figure 6 It is the bit error rate curve diagram described in Embodiment 9. Specific implementation mode

[0045] Embodiment 1. A channel estimation method for channel impulse response sum based on subcarrier sequence described in this embodiment, the method is as follows:

[0046] Step of selecting subcarrier interval: Select the subcarrier interval as L for a channel where the maximum tap of the channel delay is less than L;

[0047] Step of calculating the number of subcarrier times: There are N subcarrier sequences for subcarrier cyclic shift, which are ψ0(n), ψ1(n), ψ2(n),..., ψ n (n), the number of loaded subcarriers is k, k = [N / L], [] represents rounding down;

[0048] Step of selecting data transmission: The subcarrier sequence for data transmission is ψ i (n), ψ i+L (n), ψ i+2L (n),... ψ i+kL (n), i < L, a total of k data are transmitted, and the transmitted data sequence is X N×1 = [x(0), 0,..., 0, x(1), 0,..., x(k)] T ;

[0049] Step of selecting pilot subcarriers: The pilot subcarriers for channel estimation are ψ i (n), and the data transmitted on the subcarrier is selected as x(0);

[0050] Step of generating transmission symbols: Multiply the subcarrier sequence for data transmission by the data sequence transmitted on the subcarrier, and the sum of the obtained sequences is a new sequence, and the new sequence is the transmission symbol;

[0051] Step of receiving symbols: The transmission symbol is sent to the channel, undergoes channel attenuation, and is superimposed with channel noise, and reaches the receiving end. The transmission symbol received by the receiving end is the received symbol;

[0052] Step of calculating the channel estimation value: The received symbol and the subcarrier ψ i(n) performing a cyclic correlation calculation at point L, summing the sequence of the cyclic correlation calculations at point L, dividing the sum by the data x(0) transmitted by the subcarrier, and obtaining a channel impulse response and a channel estimation value of each subcarrier passing through the channel.

[0053] The subcarrier spacing described in this embodiment can avoid inter-carrier interference caused by cyclic shift characteristics of different subcarrier sequences. The subcarrier spacing is larger than the maximum delay tap, which can avoid inter-carrier interference caused by channel multipath effect and subcarrier cyclic shift characteristics during channel estimation.

[0054] The steps of selecting the subcarrier spacing in this implementation manner are as follows:

[0055] The existing channel equalization estimation methods all accurately estimate the channel state information to see the impact of the channel state on each point of the signal, whether it is the estimation of each frequency point or the separation and gain estimation of each delay path. The channel estimation method based on the subcarrier sequence for channel impulse response and described in this embodiment uses the ideal autocorrelation characteristics of the subcarrier sequence to perform circular convolution summation, and estimates the channel impulse response and of multiple parallel transmission symbols passing through the channel. The pilot is a selected subcarrier, which is transmitted simultaneously with the data subcarrier and experiences the same channel state, which can effectively reduce the impact of channel time variability on channel estimation. When the maximum delay tap of the channel is less than the subcarrier spacing, the channel information summation estimation can be performed on the channel through which the signal passes. There is no need to accurately distinguish the channel multipath and its channel gain, which can reduce the difficulty of accurate channel estimation and the error caused by accurate estimation.

[0056] Implementation method 2. See Figure 1 This embodiment describes the subcarriers in the channel estimation method based on subcarrier sequence for channel impulse response and channel estimation described in Embodiment 1. The subcarrier sequence is a sequence with ZC sequence properties and cyclic shift characteristics.

[0057] The subcarrier sequence described in this embodiment is a sequence having a ZC sequence property and a cyclic shift characteristic, such as a column sequence of a Fresnel transform matrix.

[0058] This implementation manner takes the Fresnel transform subcarrier chirp sequence as an example to illustrate.

[0059] The data sequence is X = [x(0), x(1), ..., x(N-1)] T , similar to the multi-carrier modulation method, the modulation process of the system is as follows Figure 1 As shown, each chirp subcarrier is modulated by a data symbol, and all modulated chirp subcarriers are added together to obtain a transmission symbol, which is expressed as:

[0060]

[0061] The kth (k=0,...,N-1) subcarrier signal is expressed as:

[0062]

[0063] When N=1, the system degenerates into a traditional linear frequency modulation spread spectrum system, in which each chirp signal is orthogonal to each other, and there is:

[0064]

[0065] According to formula (3), the signal is restored by matched filtering:

[0066]

[0067] Implementation method three. This implementation method is a specific description of the cyclic correlation calculation of the L point in the channel estimation method based on the subcarrier sequence for channel impulse response and implementation method one, and the cyclic correlation calculation of the L point is:

[0068] The received symbol is a sequence a = [a(0), a(1), ..., a(N-1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1), ..., b(N-1)]. A circular correlation operation of L points is performed on sequence a and sequence b, and the result is an L-point long sequence c = [c(0), c(1), ..., c(L-1)].

[0069] In practical applications, the sequence c is also summed, expressed as:

[0070] c(k)=a(0)·b * (k)+a(1)·b * (k+1)+...+a(N-1)·b * (L)

[0071] This implementation method specifically describes the cyclic correlation calculation at point L. Since the subcarrier sequence has an ideal autocorrelation characteristic, in the absence of noise interference, the subcarrier sequence performs cyclic correlation calculation at point L, and the result is the channel impulse response at point L. However, since the channel delay tap length is L+1 and there is a cyclic shift characteristic between subcarriers, in order to reduce the amount of calculation, it is only necessary to calculate the known subcarrier ψ at the receiving end. i (n) Performing cyclic correlation calculations at points greater than or equal to L, obtaining complete channel information, and reducing the noise accumulated in the channel estimate during subsequent addition and summation.

[0072] Embodiment 4. A channel estimation device for performing channel impulse response and channel estimation based on a subcarrier sequence, the device comprising:

[0073] Apparatus for selecting subcarrier spacing: a storage device for selecting the subcarrier spacing as L and used for a channel whose maximum tap of the channel delay is less than L;

[0074] Apparatus for calculating the number of subcarriers: a storage device for obtaining the number of subcarriers of the payload as k, k = [N / L], where [] represents rounding down, according to that there are N subcarrier sequences in total for subcarrier cyclic shift, which are ψ0(n), ψ1(n), ψ2(n),..., ψ n (n);

[0075] Apparatus for selecting data transmission: a storage device for selecting the data transmission subcarrier sequence as ψ i (n), ψ i+L (n), ψ i+2L (n),... ψ i+kL (n), i < L, and transmitting k data in total, and selecting the transmitted data sequence as X N×1 = [x(0), 0,..., 0, x(1), 0,..., x(k)] T ;

[0076] Apparatus for selecting pilot subcarriers: a storage device for the pilot subcarriers used for channel estimation as ψ i (n) and selecting the data transmitted on the subcarrier as x(0);

[0077] Apparatus for generating transmission symbols: a storage device for multiplying the subcarrier sequence for data transmission by the data sequence transmitted on the subcarrier, adding the obtained sequences to obtain a new sequence, and the new sequence being the transmission symbol;

[0078] Apparatus for receiving symbols: a storage device for sending the transmission symbol to the channel, after channel attenuation and adding channel noise, reaching the receiving end, and the transmission symbol received at the receiving end being the received symbol;

[0079] Apparatus for calculating the channel estimation value: a storage device for performing L - point cyclic correlation calculation on the received symbol and the subcarrier ψ i (n), summing the sequence of the L - point cyclic correlation calculation, and dividing the sum value of the summation by the data x(0) transmitted on the subcarrier to obtain the channel estimation value of the channel impulse response sum of the subcarrier passing through the channel.

[0080] Embodiment 5. This embodiment specifically describes the subcarrier sequence in a channel estimation apparatus for channel impulse response sum based on subcarrier sequences described in Embodiment 4, and the subcarrier sequence is a sequence with ZC sequence properties and cyclic shift characteristics.

[0081] Implementation VI. This implementation is a specific description of the cyclic correlation calculation of the L point in the channel estimation device based on the subcarrier sequence for performing the channel impulse response and the channel estimation according to Implementation IV, wherein the cyclic correlation calculation of the L point is:

[0082] The received symbol is a sequence a = [a(0), a(1), ..., a(N-1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1), ..., b(N-1)]. A circular correlation operation of L points is performed on sequence a and sequence b, and the result is an L-point long sequence c = [c(0), c(1), ..., c(L-1)].

[0083] Embodiment 7. A computer device includes a memory and a processor, wherein the memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes a channel estimation method based on a subcarrier sequence and a channel impulse response as described in any one of embodiments 1 to 3.

[0084] Implementation 8. See Figure 2 and Figure 3 The present embodiment is described. The present embodiment describes a receiving method for channel estimation of a multi-channel parallel transmission system based on a subcarrier sequence. The method is implemented based on a channel estimation method based on a subcarrier sequence for channel impulse response and the like described in the first embodiment. The transmission symbol passes through the channel and reaches the receiving end. The transmission symbol received by the receiving end is the receiving symbol. The cyclic prefix is ​​removed from the receiving symbol. The data is divided into two paths. One path is used for channel estimation and compared with the subcarrier sequence ψ stored at the receiving end. i (n) performing a cyclic correlation calculation at point L, summing a sequence of the cyclic correlation calculations at point L, and dividing the sum by the data x(0) transmitted by the subcarrier to obtain a channel impulse response and a channel estimation value;

[0085] The other data is respectively connected to the transmission data subcarrier sequence ψ stored at the receiving end i (n), ψ i+L (n), ψ i+2L (n), ..., ψ i+kL (n), perform L-point cyclic correlation calculation, sum the sequence of the L-point cyclic correlation calculation, divide the sum by the channel impulse response and the channel estimation value, recover the data information transmitted on each subcarrier, perform digital demodulation, and restore the information sequence.

[0086] The receiving method for channel estimation of a multi-channel parallel transmission system based on a subcarrier sequence described in this embodiment is actually applied, see Figure 2As shown, the information sequence is digitally modulated, and after serial-to-parallel conversion, carrier modulation is performed according to the selected subcarrier interval, wherein the selected pilot subcarrier directly modulates the known data x(0), and the data subcarrier modulates the data to be transmitted. After modulation, the data are added to obtain the transmission sequence, and the baseband modulation of the transmitter is completed after adding the cyclic prefix.

[0087] The receiving method for channel estimation of a multi-path parallel transmission system based on a subcarrier sequence described in this embodiment can restore the information sequence, which is different from the RAKE receiver commonly used in the spread spectrum transmission system in the prior art. The RAKE receiver needs to perform accurate channel estimation on each delay path in the multipath channel and needs to accurately separate each delay path, which increases the difficulty of channel estimation when there are many multipaths. The implementation method only needs to estimate the impulse response and of the entire channel, and does not need to separate each delay multipath, which reduces the difficulty of channel estimation and the error caused by accurate estimation while ensuring the integrity of channel information.

[0088] Implementation method 9. See Figure 4 , Figure 5 and Figure 6 This embodiment is explained. This embodiment verifies that the channel estimation value obtained in the channel estimation method based on the subcarrier sequence for channel impulse response and is the same in each transmission data subcarrier, and is the channel impulse response and. This embodiment selects a quasi-static multipath channel with a channel delay tap of [0, 3, 7, 13] for simulation analysis. The transmission system adopts an orthogonal chirp multiplexing technology in which the subcarrier chirp signal has an ideal autocorrelation characteristic. The number of subcarriers of the symbol N=256, the subcarrier interval is 16, and the transmission data adopts 16QAM modulation of amplitude and phase. The influence of channel noise is ignored. The channel estimation method based on the subcarrier sequence for channel impulse response and is described in the first embodiment to obtain the channel estimation value of each transmission information subcarrier, such as Figure 4 and Figure 5 shown.

[0089] See also Figure 4 and Figure 5 As shown, the amplitude and phase of the estimated value obtained by the channel estimation method based on the subcarrier sequence for channel impulse response and θ for each subcarrier performing data transmission described in Implementation Method 1 are the same, and are equal to the amplitude value and phase value of the channel impulse response and θ.

[0090] See also Figure 6 As shown, Figure 6 The bit error rate curve obtained by using the channel estimation method based on the subcarrier sequence for channel impulse response as described in Implementation Method 1 shows that the signal information is demodulated correctly.

[0091] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A channel estimation method based on a subcarrier sequence for channel impulse response and channel estimation, characterized in that: The method comprises the steps of: selecting a subcarrier spacing: selecting a subcarrier spacing of L, for a channel with a maximum channel delay tap less than L; Steps for calculating the number of subcarriers: There are N subcarrier sequences for subcarrier cyclic shift, namely ψ0(n), ψ1(n), ψ2(n),..., ψ N-1 (n), the number of subcarriers in the load is k, k = [N / L], [] means rounding down; Steps for selecting data transmission: The subcarrier sequence for data transmission is ψ i (n), ψ i+L (n), ψ i+2L (n),... ψ i+kL (n), i < L, a total of k data are transmitted, and the transmitted data sequence is X N×1 = [x(0), 0,..., 0, x(1), 0,..., x(k)] T ; Steps for selecting pilot subcarriers: The pilot subcarrier used for channel estimation is ψ i (n), the data transmitted by the selected subcarrier is x(0); The step of generating transmission symbols: the subcarrier sequence of the data transmission is multiplied by the data sequence transmitted by the subcarrier, and the obtained sequences are added to form a new sequence, and the new sequence is the transmission symbol; Step of receiving symbols: the transmission symbol is sent to the channel, attenuated by the channel, superimposed with channel noise, and reaches the receiving end. The transmission symbol received by the receiving end is the receiving symbol; Step of calculating the channel estimation value: the received symbol and the subcarrier ψ i (n) performing a cyclic correlation calculation at point L, summing the sequence of the cyclic correlation calculations at point L, dividing the sum by the data x(0) transmitted by the subcarrier, and obtaining a channel impulse response and a channel estimation value of each subcarrier passing through the channel.

2. A channel estimation method based on subcarrier sequence for channel impulse response and channel estimation according to claim 1, characterized in that: The subcarrier sequence is a sequence having a ZC sequence property and a cyclic shift characteristic.

3. The channel estimation method based on subcarrier sequence for channel impulse response and channel estimation according to claim 1, characterized in that: The circular correlation calculation of the L point is: The received symbol is a sequence a = [a(0), a(1), ..., a(N-1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1), ..., b(N-1)]. A circular correlation operation of L points is performed on sequence a and sequence b, and the result is an L-point long sequence c = [c(0), c(1), ..., c(L-1)].

4. A channel estimation system based on a subcarrier sequence for channel impulse response and channel estimation, characterized in that: The system comprises: Device for selecting subcarrier spacing: a storage device for selecting a subcarrier spacing of L, for a channel with a maximum channel delay tap less than L; The device for calculating the number of subcarriers is used to calculate the total number of N subcarrier sequences according to the subcarrier cyclic shift, which are ψ0(n), ψ1(n), ψ2(n), ..., ψ N-1 (n), a storage device for obtaining a subcarrier number of a load of k, k = [N / L], [] represents rounding down; Apparatus for selecting data transmission: for a subcarrier sequence ψ i (n), ψ i+L (n), ψ i+2L (n),... ψ i+kL (n), i < L, a total of k data are transmitted, and the selected data sequence for transmission is X N×1 = [x(0), 0,..., 0, x(1), 0,..., x(k)] T Storage device; Device for selecting pilot subcarrier: The pilot subcarrier used for channel estimation is ψ i (n), a storage device for selecting the data transmitted by the subcarrier as x(0); A transmission symbol generating device: a device for multiplying the subcarrier sequence of the data transmission by the data sequence of the subcarrier transmission, and adding the obtained sequences into a new sequence, which is a storage device for the transmission symbol; A receiving symbol device: a storage device for sending the transmission symbol to a channel, where the transmission symbol is transmitted to a receiving end after being attenuated by the channel and superimposed with channel noise, and the transmission symbol received by the receiving end is a receiving symbol; A device for calculating a channel estimation value: for combining the received symbol and the subcarrier ψ i (n) performing a cyclic correlation calculation at point L, summing a sequence of the cyclic correlation calculations at point L, dividing the sum by the data x(0) transmitted by the subcarrier, and obtaining a channel impulse response and a channel estimation value of the subcarrier passing through the channel.

5. A channel estimation system based on subcarrier sequence for channel impulse response and channel estimation according to claim 4, characterized in that: The subcarrier sequence is a sequence having a ZC sequence property and a cyclic shift characteristic.

6. A channel estimation system based on subcarrier sequence for channel impulse response and channel estimation according to claim 4, characterized in that: The circular correlation calculation of the L point is: The received symbol is a sequence a = [a(0), a(1), ..., a(N-1)], and the local subcarrier sequence at the receiving end is b = [b(0), b(1), ..., b(N-1)]. A circular correlation operation of L points is performed on sequence a and sequence b, and the result is an L-point long sequence c = [c(0), c(1), ..., c(L-1)].

7. A computer device comprising a memory and a processor, characterized in that: A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the method according to any one of claims 1 to 3.

8. A receiving method for channel estimation of a multi-channel parallel transmission system based on a subcarrier sequence, characterized in that: The receiving method comprises: receiving a signal, removing a cyclic prefix from the signal and dividing the signal into two paths: One way is to use the channel estimation method described in claim 1 to perform channel estimation to obtain a channel impulse response and a channel estimation value; The other data is respectively connected to the transmission data subcarrier sequence ψ stored at the receiving end i (n), ψ i+L (n), ψ i+2L (n), ..., ψ i+kL An L-point cyclic correlation calculation is performed on each subcarrier in (n). After the sequence obtained by each L-point cyclic correlation calculation is summed, it is divided by the obtained channel estimation value to obtain the data information transmitted on each subcarrier after recovery. The data of all the obtained subcarriers are digitally demodulated to restore the information sequence.

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