CN114884777B - Channel estimation method based on transform domain - Google Patents

Abstract

The present invention provides a method for placing a pilot signal in a channel in wireless communication, including obtaining a pilot signal, mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal; superimposing the transformed pilot signal and a data signal in the time-frequency domain to obtain a superimposed signal; the present invention considers mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal; superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal. Thus, the transformed pilot signal and the data signal can be superimposed together for transmission, thereby improving the transmission efficiency; in addition, since the pilot signal is first mapped to the delay Doppler domain and then transformed to the time-frequency domain, the pilot signal transformed to the time-frequency domain will be evenly dispersed in the time-frequency resource plane by utilizing the orthogonality of the delay Doppler domain and the time-frequency domain, thereby reducing the interference between the pilot signal and the data signal and improving the transmission performance.

Description

A channel estimation method based on transform domain

Technical Field

The present invention relates to the field of wireless communications, in particular to the field of channel estimation in wireless communications, and more particularly to a transform domain-based channel estimation method in wireless communications.

Background technique

In wireless communication systems, due to the complex and changeable wireless channel between the transmitter and the receiver, the wireless signal will cause the corresponding received signal to be distorted after passing through the wireless channel. In order to correctly decode the signal sent by the transmitter, the receiver needs to perform channel estimation and compensate the received signal based on the channel estimation result.

The existing technical solutions for implementing channel estimation mainly include the following two:

Solution 1: By dividing the time-frequency resources for the pilot signal, the time-frequency resources are divided into a part for transmitting data signals and a part for transmitting pilot signals, and the pilot signal is placed in the time-frequency resources for transmitting pilot signals. However, since the pilot signal occupies a certain amount of overhead in Solution 1, the actual channel transmission utilization rate is low and the transmission efficiency is not high. Therefore, the researchers proposed Solution 2.

Solution 2: Superimpose the pilot signal and the data signal in the time-frequency domain to improve the utilization of time-frequency resources. Perform channel estimation at the receiving end by eliminating interference. Although Solution 2 can improve channel transmission efficiency, it will cause interference between signals, reduce transmission performance, and thus affect the performance of the receiver in extracting data from the corresponding received signal.

Therefore, it is necessary to improve the existing technology to improve the transmission performance while effectively ensuring the transmission efficiency.

Summary of the invention

Therefore, the object of the present invention is to overcome the above-mentioned defects of the prior art and provide a channel estimation method based on transform domain in wireless communication.

The objective of the present invention is achieved through the following technical solutions:

According to a first aspect of the present invention, there is provided a method for placing a pilot signal (or a method for placing a pilot signal in wireless communication), comprising: acquiring a pilot signal, mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal; acquiring a data signal, mapping the data signal to the time-frequency domain, and superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal.

In some embodiments of the present invention, the transformed pilot signal and data signal are linearly superimposed in the time-frequency domain to obtain a superimposed signal.

In some embodiments of the present invention, the pilot signal is linearly superimposed on the time slot resources occupied by the data signal, and does not occupy other time slot resources besides the time slot resources occupied by the data signal.

According to a second aspect of the present invention, there is provided a method for sending a wireless signal, comprising: obtaining information bits, encoding and modulating the information bits to obtain a data signal; superimposing a pilot signal on the data signal based on the method for placing a pilot signal described in the first aspect to obtain a stacked signal; and sending the stacked signal in the form of a wireless signal.

According to a third aspect of the present invention, there is provided a channel estimation method, comprising: obtaining a received signal corresponding to a wireless signal sent by the method for sending a wireless signal according to the second aspect; performing channel estimation after transforming the received signal into a delay Doppler domain to obtain a channel estimation result.

In some embodiments of the present invention, the step of performing channel estimation after transforming the received signal into the delay Doppler domain to obtain the channel estimation result includes: after transforming the received signal into the delay Doppler domain, detecting the pilot signal from the received signal represented by the delay Doppler domain according to a predetermined detection threshold to obtain an initial channel estimation result; performing channel equalization on the data signal in the received signal based on the initial channel estimation result to obtain the data signal after channel equalization; subtracting the data signal and noise after channel equalization of the data signal in the received signal according to the current channel estimation result from the received signal to obtain the received signal after interference elimination; after transforming the received signal after interference elimination into the delay Doppler domain, detecting the pilot signal from the received signal after interference elimination represented by the delay Doppler domain according to a predetermined detection threshold to obtain the channel estimation result.

According to a fourth aspect of the present invention, a signal processing method is provided, which is characterized in that it includes: receiving a wireless signal sent according to the method for sending a wireless signal according to the second aspect, and obtaining a corresponding received signal; performing channel estimation on a channel transmitting the wireless signal according to the channel estimation method according to the third aspect and the received signal corresponding to the wireless signal, and obtaining a channel estimation result; and processing a data signal in the received signal according to the channel estimation result to extract information bits.

According to a fifth aspect of the present invention, a wireless communication method is provided, which is used in a wireless communication system including a transmitting end and a receiving end, and the wireless communication method includes: obtaining information bits by the transmitting end, encoding and modulating the information bits to obtain a data signal; obtaining a pilot signal by the transmitting end, mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal; obtaining a data signal by the transmitting end, mapping the data signal to a time-frequency domain, superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal; sending the superimposed signal in the form of a wireless signal by the transmitting end; receiving the wireless signal sent by the transmitting end to obtain a corresponding received signal; transforming the received signal to the delay Doppler domain by the receiving end to perform channel estimation to obtain a channel estimation result; processing the data signal in the received signal by the receiving end according to the channel estimation result to extract the information bit.

According to the sixth aspect of the present invention, an electronic device is provided, characterized in that it includes: one or more processors; and a memory, wherein the memory is used to store executable instructions; the one or more processors are configured to implement the steps of the method described in the first aspect, the second aspect, the third aspect, the fourth aspect and/or the fifth aspect by executing the executable instructions.

Compared with the prior art, the advantages of the present invention are:

The present invention considers mapping the pilot signal to the delay Doppler domain and then transforming it to the time-frequency domain to obtain a transformed pilot signal; superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal. Thus, the transformed pilot signal and the data signal can be superimposed together for transmission, thereby improving the transmission efficiency; in addition, since the pilot signal is first mapped to the delay Doppler domain and then transformed to the time-frequency domain, the pilot signal transformed to the time-frequency domain will be evenly dispersed in the time-frequency resource plane by utilizing the orthogonality of the delay Doppler domain and the time-frequency domain, thereby reducing the interference between the pilot signal and the data signal and improving the transmission performance.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

FIG1 is a schematic diagram of a flow chart of a wireless communication method according to an embodiment of the present invention;

FIG2 is a transformation relationship between the delay-Doppler domain and the time-frequency domain according to an embodiment of the present invention;

3 is a schematic diagram showing the distribution of pilot signals in the delay-Doppler domain and the time-frequency domain according to an embodiment of the present invention;

FIG4 is a schematic diagram of distribution of a data signal in the time-frequency domain according to an embodiment of the present invention;

5 is a schematic diagram of signal superposition of a transformed pilot signal and a data signal in the time-frequency domain according to an embodiment of the present invention;

FIG6 is a schematic diagram of detecting a pilot signal according to an embodiment of the present invention;

FIG. 7 is a schematic diagram showing a principle of processing a received signal of a wireless signal according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail by specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

As mentioned in the background technology section, although the scheme of directly superimposing the pilot signal and the data signal in the time-frequency domain can improve the channel transmission efficiency, it brings interference between signals, reduces the transmission performance, and further affects the performance of the receiver in extracting data from the corresponding received signal. Therefore, the present invention considers mapping the pilot signal to the delay Doppler domain and then transforming it to the time-frequency domain to obtain a transformed pilot signal; superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal. Thus, the transformed pilot signal and the data signal can be superimposed together for transmission, which improves the transmission efficiency; in addition, since the pilot signal is first mapped to the delay Doppler domain and then transformed to the time-frequency domain, the orthogonality of the delay Doppler domain and the time-frequency domain is utilized, and the pilot signal transformed to the time-frequency domain will be evenly dispersed in the time-frequency resource plane, reducing the interference between the pilot signal and the data signal, and improving the transmission performance.

Implementation 1:

According to one aspect of the present invention, in view of the shortcomings of the current existing methods, a method is provided from the signal transmission level that can effectively ensure transmission efficiency and improve transmission performance. According to one embodiment of the present invention, a wireless communication system is provided, the wireless communication system includes a transmitting end and a receiving end; the wireless communication system is configured to perform a wireless communication method, and the wireless communication method includes: steps S1, S2, S3, S4, S5, S5, S7. In order to better understand the present invention, each step is described in detail below in combination with specific embodiments.

Step S1: The transmitting end obtains information bits, and encodes and modulates the information bits to obtain data signals.

According to one embodiment of the present invention, information bits refer to data to be sent consisting of 0 and 1 bits. The coding rules used to encode the information bits may be coding rules corresponding to Polar codes, LDPC codes and/or Turbo codes, or other existing available coding rules, or even new coding rules that appear after this application, as long as they do not conflict with the principles of the present invention, they can still be used, and the present invention does not impose any restrictions on this. After encoding the information bits, a code word is obtained, and the code word is modulated to obtain a data signal. The modulation method may adopt existing modulation methods such as quadrature amplitude modulation (QAM), Gaussian filtered minimum shift key modulation (GMSK), and even new modulation methods that appear after this application, as long as they do not conflict with the principles of the present invention, they can still be used, and the present invention does not impose any restrictions on this.

Step S2: The transmitting end obtains a pilot signal, maps the pilot signal to the delay-Doppler domain and then transforms it to the time-frequency domain to obtain a transformed pilot signal.

According to one embodiment of the present invention, the step of mapping the pilot signal to the delay-Doppler domain and then transforming it to the time-frequency domain includes: the transmitting end maps the pilot signal to the delay-Doppler domain (i.e., the delay-Doppler domain, Delay-Doppler, abbreviated as DD) to obtain the pilot signal represented in the delay-Doppler domain; the transmitting end transforms the pilot signal represented in the delay-Doppler domain to the time-frequency domain (i.e., the time-frequency domain, Time-Frequency, abbreviated as TF) through the inverse finite sigmoid Fourier transform (ISFFT) to obtain the transformed pilot signal. Since the delay-Doppler domain and the time-frequency domain are orthogonal, the pilot signal transformed to the time-frequency domain will be evenly distributed in the time-frequency resource plane, reducing the interference between the pilot signal and the data signal and improving the transmission performance.

Step S3: The transmitting end obtains the data signal, maps the data signal to the time-frequency domain, and superimposes the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal.

According to one embodiment of the present invention, the present invention maps the data signal to the time-frequency domain, and then linearly superimposes the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal. That is, the data signal is obtained, the data signal is mapped to the time-frequency domain, and the transformed pilot signal and the data signal are superimposed in the time-frequency domain to obtain a superimposed signal. Preferably, the pilot signal is linearly superimposed on the time slot resources occupied by the data signal, and does not occupy other time slot resources outside the time slot resources occupied by the data signal. For example, assuming that the value of the transformed pilot signal in a certain time slot is A, and the value of the data signal in the time slot is B, then in the superimposed signal, the value of the time slot = A + B.

Step S4: The transmitting end sends the superimposed signals in the form of wireless signals.

According to one embodiment of the present invention, the superimposed signals are transmitted through an antenna at the transmitting end.

Step S5: The receiving end receives the wireless signal sent by the transmitting end to obtain a corresponding received signal.

According to an embodiment of the present invention, a wireless signal is received by an antenna at a receiving end to obtain a corresponding received signal.

Step S6: The receiving end transforms the received signal into the delay-Doppler domain and then performs channel estimation to obtain a channel estimation result.

According to one embodiment of the present invention, the receiving end performs a finite sigmoid Fourier transform (SFFT) on the received signal to obtain a received signal represented in the delay-Doppler domain. The channel estimation result is the estimated channel parameter (some documents also refer to channel state information, Channel State Information, abbreviated as CSI). For example, in some communication systems, the channel parameters include Doppler shift, delay and channel coefficient. However, it should be understood that the specific types of channel parameters that need to be estimated may be different in different communication systems; when detecting the pilot signal, the corresponding channel parameters can be obtained based on the corresponding channel estimation algorithm, and the present invention does not impose any restrictions on this.

According to one embodiment of the present invention, step S6 includes:

S61: after transforming the received signal into the delay-Doppler domain, detecting the pilot signal from the received signal represented in the delay-Doppler domain according to a predetermined detection threshold, and obtaining an initial channel estimation result;

S62: performing channel equalization on the data signal in the received signal based on the initial channel estimation result to obtain a data signal after channel equalization;

S63: Subtract the data signal and noise after channel equalization of the data signal in the received signal according to the current channel estimation result from the received signal to obtain the received signal after interference elimination; (Step S63 is equivalent to removing the influence of the data signal and noise in the received signal to better detect the pilot)

S64: After transforming the interference-eliminated received signal into the delay-Doppler domain, a pilot signal is detected from the interference-eliminated received signal represented in the delay-Doppler domain according to a predetermined detection threshold to obtain a channel estimation result.

Preferably, in step S64, an intermediate channel estimation result may be obtained, and steps S63 and S64 need to be repeated for a predetermined number of times to obtain a final channel estimation result (in the subsequent description of this application, the channel estimation result refers to the final channel estimation result). Thus, iterative interference elimination is performed to obtain a more accurate channel estimation result.

Step S7: The receiving end processes the data signal in the received signal according to the channel estimation result to extract the information bits.

According to an embodiment of the present invention, the step of processing the data signal in the received signal according to the channel estimation result includes: performing channel equalization using the channel estimation result after subtracting the pilot signal from the received signal, and performing demodulation and decoding according to the result of the channel equalization to obtain information bits. It should be understood that the channel equalization, demodulation or decoding method can adopt the existing channel equalization, demodulation or decoding technology method, or even a new method after the present application, and the present invention does not impose any limitation on this.

The pilot placement technique and channel estimation technique of the present application are described below with reference to specific examples.

First, some schematic parameter settings required for this example are as follows:

Taking the orthogonal frequency division multiplexing system (OFDM system for short) as an example, assuming that the system bandwidth of the OFDM system is B = MΔf (Hz), the duration of a single time slot is _Tf = NT, where M represents the total number of subcarriers, Δf (Hz) represents the subcarrier frequency interval, N represents the total number of OFDM symbols, an OFDM symbol contains M signals, T represents the duration period of a single OFDM symbol, T = 1/Δf. Therefore, the number of available resources in the time-frequency domain is MN and the corresponding number of available resources in the delay-Doppler domain is MN, and each wireless signal sent occupies a resource grid.

The time-frequency resource plane is expressed as: Λ＝{(nT,mΔf),n＝0,…,N-1,m＝0,…,M-1}, N,M＞0, N represents the total number of transmitted OFDM symbols, M represents the total number of subcarriers, n represents the nth OFDM symbol, and m represents the mth subcarrier;

The signal in the time-frequency domain is represented as: X[n,m], n=0,…,N-1, m=0,…,M-1; the corresponding received signal is represented as: Y[n,m];

The delay-Doppler resource plane is expressed as: Delay interval τ = 1/MΔf, Doppler interval ν = 1/NT, k represents the kth delay interval, l represents the lth Doppler interval;

The signal in the delay-Doppler domain is expressed as: x[k,l], k=0,…,N-1, l=0,…,M-1; the corresponding received signal is expressed as: y[k,l].

The delay-Doppler domain impulse response of a wireless channel is expressed as:

Where P is the number of multipaths, _hi represents the channel coefficient of the ith path, τ represents the delay interval, τ _i represents the delay of the ith path, ν represents the Doppler interval, ν _i represents the Doppler shift of the ith path, and δ(·) represents the impulse function. Therefore, by estimating the channel coefficient, delay, and Doppler shift of the channel, complete channel information (corresponding to the channel estimation result) can be obtained.

According to the above schematic setting parameters, the wireless signal can be represented in the time-frequency (TF) domain (corresponding to the time-frequency domain), and can also be represented in the delay-Doppler (DD) domain (corresponding to the delay Doppler domain), wherein the delay Doppler domain is shown in Figure 2a, and the time-frequency domain is shown in Figure 2b, and the two domains can be transformed into each other through ISFFT and SFFT; wherein the signal in the delay Doppler domain can be converted into the signal in the time-frequency domain through the inverse finite symplectic Fourier transform, and the signal in the time-frequency domain can also be converted into the delay Doppler domain and the time-frequency domain through the finite symplectic Fourier transform.

According to an example of the present invention, a wireless communication method is shown, including steps K1, K2, K3, K4, K5, K6, and K7. Among them: step K1 corresponds to step S1 in implementation mode 1; steps K2 and K3 correspond to steps S3 and S4 in implementation mode 1; steps K4, K5, and K6 correspond to steps S5 and S6 in implementation mode 1; and step K7 corresponds to step S7 in implementation mode 1.

K1. Map the pilot signal in the delay-Doppler domain and then transform it to the time-frequency domain (corresponding to the time-frequency domain) through the inverse finite sigmoid Fourier transform (ISFFT).

Among them, the formula corresponding to ISFFT is as follows:

Here, j represents an imaginary number.

For example, as shown in FIG3a, the pilot signal The power of the pilot signal is generally set to be 20 dB higher than that of the data signal, so as to facilitate better channel estimation. Then, as shown in Figure 3b, the inverse finite symplectic Fourier transform (ISFFT) is used to transform the signal to the time-frequency domain. Here, one pilot signal occupies one resource grid in the delay-Doppler domain. After transformation, MN pilot signals in the time-frequency domain occupy the entire time-frequency resource plane (when sending a pilot signal, the energy of the pilot signal will be evenly distributed to the entire time-frequency resource plane. When superimposed, the interference of the pilot signal to the data signal will be greatly reduced compared to the existing technology of directly superimposing the two, thereby improving the transmission performance);

K2. Map the data signal to the time-frequency domain.

For example, MN data signals Mapped to the time-frequency domain, each data signal occupies a time-frequency resource grid, as shown in Figure 4.

K3. Superimpose the pilot signal in the time-frequency domain (corresponding to the transformed pilot signal) with the data signal and transmit the superimposed signal.

For example, the pilot signal in the time-frequency domain shown in FIG. 5a (corresponding to the transformed pilot signal) is superimposed with the data signal shown in FIG. 5b to obtain the superimposed signal shown in FIG. 5c and then transmitted; the formula corresponding to the superimposed signal is expressed as follows: in, represents the transformed pilot signal, Represents the data signal. TF in the upper right corner represents the time-frequency domain.

K4. The receiving end receives the wireless signal and obtains the corresponding received signal; the receiving end performs a finite sigmoid Fourier transform (SFFT) on the received signal (which belongs to the time-frequency signal) to transform it into the delay Doppler domain. According to the pre-set discrimination threshold value (corresponding to the predetermined detection threshold), the pilot signal is detected and the channel estimation is performed to obtain the channel estimation result, wherein the first channel estimation of a received signal is the initial channel estimation of the data signal without channel equalization, and the subsequent channel estimation of a received signal is the intermediate channel estimation or the final channel estimation of the data signal after channel equalization.

Among them, the formula corresponding to SFFT is as follows:

For example, the receiving end first performs a finite sigmoid Fourier transform (SFFT) on the received signal Y[n,m] and transforms it into the delay-Doppler domain to obtain y[k,l].

It should be understood that the pilot signal may be superimposed on part of the data signal. Therefore, the delay-Doppler domain reception y[k,l] can be divided into two categories:

Wherein, H[k,l] represents the channel state parameter at [k,l] in the delay-Doppler domain (i.e., the channel estimation result to be determined), n is Gaussian noise subject to N(0,σ ² ), x _d represents the data signal, x _d [k,l] represents the data signal at [k,l] in the delay-Doppler domain, x _p represents the pilot signal, and x _p [k,l] represents the pilot signal at [k,l] in the delay-Doppler domain. It should be understood that [k,l] in the delay-Doppler domain represents the resource block corresponding to the kth delay interval and the lth Doppler interval. When estimating the channel, the pilot signal is detected based on the discrimination threshold value, thereby detecting the pilot signal. As shown in Figure 5, after the data symbol is transformed into the delay-Doppler domain, it is regarded as data interference. When performing the initial channel estimation, the initial discrimination threshold is generally set to a value in advance; when performing the channel estimation for a certain received signal in the future, the expected power of the data interference and the power of the additive white noise are jointly considered to dynamically adjust the discrimination threshold. The dynamic discrimination threshold is set to Among them, SINR _P represents the signal to interference and noise ratio of the pilot signal, E{} represents expectation, x _d represents data signal, σ ² represents white noise variance, which is E{x _d } ² =SNR _d σ ² , SNR _d represents data signal noise ratio. The signal to interference noise ratio of the pilot signal and the signal to noise ratio of the data signal can be dynamically adjusted according to the result of the previous channel estimation, so the discrimination threshold value can be dynamically adjusted accordingly. According to the discrimination threshold value, the pilot signal is detected to obtain three parameters of the channel: Doppler shift, delay, and channel coefficient. As an illustration, the received signal is shown in FIG6a , and after the received signal is converted from the time-frequency domain to the delay-Doppler domain, the detected pilot signal is shown in FIG6b (it should be understood that although there is only one pilot signal in the schematic diagram corresponding to FIG3a , due to the multipath effect, the receiving end receives the corresponding pilot signals at different resource blocks, for example, as shown in FIG6b , 4 pilot signals are received). It should be understood that the dynamic judgment threshold value given above is only for illustration, and is intended only to illustrate that channel estimation can be performed through multiple rounds of iterations to obtain a better channel estimation result. There are other initial settings and adjustment methods for the judgment threshold value of channel estimation that can be applied to the present invention in the prior art, and the present invention does not impose any limitations on this.

K5. The receiving end performs channel equalization of the data signal based on the current channel estimation result.

K6, subtract the additive white noise and the equalized data signal from the received signal, and then execute steps K4-K6 in sequence to perform iterative interference elimination, and go to step K7 after repeating a predetermined number of times; the schematic diagram of the cyclic iteration process is shown in Figure 7.

For example, the receiving end performs signal detection on the TF domain signal based on the current channel estimation result, and performs interference elimination on the DD domain signal based on the signal detection result to remove the interference of the data signal and additive white noise on the pilot signal; the DD domain signal after interference elimination is used as the input signal, and the above steps K4-K6 are iteratively executed to obtain a more accurate channel estimation result, and the threshold value is optimized according to the current data signal signal-to-noise ratio and the pilot signal signal-to-noise ratio in each iteration. Generally, 2-5 rounds of iterations can obtain the final channel estimation result with high reliability;

K7. Demodulate and decode the data signal based on the final channel estimation result and the received signal.

Here, the receiving end completes the detection of the data signal according to the final channel estimation result, obtains the data to be decoded, and finally decodes to obtain the information bit. For example, at the receiving end, according to the final channel estimation result, the pilot signal is subtracted from the received signal, and the obtained signal minus the pilot signal is channel-equalized to obtain the data signal after channel equalization; the data signal after channel equalization is demodulated to obtain the data to be decoded; the data to be decoded is decoded to obtain the information bit.

Implementation Method 2

According to one embodiment of the present invention, a method for placing a pilot signal is provided, comprising: acquiring a pilot signal, mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal (the specific implementation details can refer to step S2 in implementation mode 1, which will not be repeated here); acquiring a data signal, mapping the data signal to the time-frequency domain, and superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal (the specific implementation details can refer to step S3 in implementation mode 1, which will not be repeated here).

Implementation 3

According to an embodiment of the present invention, a method for sending a wireless signal is provided, comprising: obtaining information bits, encoding and modulating the information bits to obtain a data signal (specific implementation details may refer to step S1 in implementation mode 1, which will not be described in detail herein);

Acquire a pilot signal, map the pilot signal to the delay-Doppler domain and then transform it to the time-frequency domain to obtain a transformed pilot signal (for specific implementation details, refer to step S2 in Implementation Method 1, which will not be repeated here); acquire a data signal, map the data signal to the time-frequency domain, and superimpose the transformed pilot signal and the data signal in the time-frequency domain to obtain a stacked signal (for specific implementation details, refer to step S3 in Implementation Method 1, which will not be repeated here); send the stacked signal in the form of a wireless signal (for specific implementation details, refer to step S4 in Implementation Method 1, which will not be repeated here).

Implementation 4

According to one embodiment of the present invention, a channel estimation method is provided, comprising: obtaining a received signal corresponding to a wireless signal sent according to the method for sending a wireless signal in Implementation 3; performing channel estimation after transforming the received signal into a delay Doppler domain to obtain a channel estimation result (the specific implementation details can be referred to step S6 in Implementation 1, which will not be repeated here).

Implementation method 5

According to one embodiment of the present invention, there is provided a signal processing method, comprising: receiving a wireless signal sent according to the method for sending a wireless signal described in Implementation 3, and obtaining a corresponding received signal; performing channel estimation on a channel transmitting the wireless signal according to the channel estimation method described in Implementation 4 and a received signal corresponding to the wireless signal, and obtaining a channel estimation result; and processing a data signal in the received signal according to the channel estimation result to extract information bits (the specific implementation details can be referred to step S7 in Implementation 1, which will not be repeated here).

It should be noted that although the above describes the various steps in a specific order, it does not mean that the various steps must be executed in the above specific order. In fact, some of these steps can be executed concurrently or even in a different order as long as the required functions can be achieved.

The present invention may be a system, a method and/or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

Computer readable storage medium can be a tangible device that holds and stores instructions used by an instruction execution device. Computer readable storage medium can include, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a protruding structure in a groove on which instructions are stored, and any suitable combination thereof.

The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (7)

1. A channel estimation method, comprising: Obtaining a received signal corresponding to a wireless signal sent according to a preset method for sending a wireless signal, wherein the method for sending a wireless signal includes: obtaining information bits, encoding and modulating the information bits to obtain a data signal; superimposing a pilot signal on the data signal based on a preset method for placing a pilot signal to obtain a superimposed signal; and sending the superimposed signal in the form of a wireless signal; the method for placing a pilot signal includes: obtaining a pilot signal, mapping the pilot signal to a delay Doppler domain and then transforming it to a time-frequency domain to obtain a transformed pilot signal; obtaining a data signal, mapping the data signal to a time-frequency domain, and superimposing the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal; After the received signal is transformed into the delay-Doppler domain, channel estimation is performed to obtain a channel estimation result, which includes: After transforming the received signal into the delay-Doppler domain, a pilot signal is detected from the received signal represented in the delay-Doppler domain according to a predetermined detection threshold to obtain an initial channel estimation result; Based on the initial channel estimation result, the data signal in the received signal is channel equalized. Obtaining a data signal after channel equalization; Subtracting the data signal and noise after channel equalization of the data signal in the received signal according to the current channel estimation result from the received signal to obtain the received signal after interference elimination; After the interference-eliminated received signal is transformed into the delay-Doppler domain, a pilot signal is detected from the interference-eliminated received signal represented in the delay-Doppler domain according to a predetermined detection threshold, and a channel estimation result is obtained. 2. The channel estimation method according to claim 1 is characterized in that the transformed pilot signal and data signal are linearly superimposed in the time-frequency domain to obtain a superimposed signal. 3. The channel estimation method according to claim 1 or 2 is characterized in that the pilot signal is linearly superimposed on the time slot resources occupied by the data signal and does not occupy other time slot resources besides the time slot resources occupied by the data signal. 4. A signal processing method, comprising: Receiving a wireless signal sent according to a preset method for sending a wireless signal, and obtaining a corresponding received signal; According to the channel estimation method according to any one of claims 1 to 3 and the received signal corresponding to the wireless signal, channel estimation is performed on the channel transmitting the wireless signal to obtain a channel estimation result; The data signal in the received signal is processed according to the channel estimation result to extract the information bits. 5. A wireless communication method, the wireless communication method being used in a wireless communication system including a transmitting end and a receiving end, the wireless communication method comprising: The transmitting end obtains information bits, and encodes and modulates the information bits to obtain data signals; A pilot signal is obtained from the transmitting end, the pilot signal is mapped to the delay-Doppler domain and then transformed to the time-frequency domain to obtain a transformed pilot signal; The transmitting end obtains the data signal, maps the data signal to the time-frequency domain, and superimposes the transformed pilot signal and the data signal in the time-frequency domain to obtain a superimposed signal; The superimposed signals are sent by the transmitting end in the form of wireless signals; The receiving end receives the wireless signal sent by the transmitting end and obtains a corresponding receiving signal; According to the channel estimation method according to any one of claims 1 to 3, the receiving end transforms the received signal into the delay Doppler domain and then performs channel estimation to obtain a channel estimation result; The receiving end processes the data signal in the received signal according to the channel estimation result to extract the information bits. 6. A computer-readable storage medium, characterized in that a computer program is stored thereon, and the computer program can be executed by a processor to implement the steps of any one of claims 1 to 5. 7. An electronic device, comprising: one or more processors; and A memory, wherein the memory is used to store executable instructions; The one or more processors are configured to implement the steps of the method of any one of claims 1 to 5 by executing the executable instructions.