CN111131106B - Frequency offset estimation method, system, storage medium and receiving device of communication signal - Google Patents

Abstract

The present invention provides a method, system, storage medium and receiving device for estimating frequency offset of a communication signal, comprising the following steps: receiving a transmission signal of length M sent by a transmitting end of a communication signal N times, and the transmission signal becomes a transmission signal after channel transmission. A received signal with a length of M*N; a cross-correlation operation is performed on the received signal and the transmitted signal to obtain N frequency offset estimated intermediate quantities r; the N frequency offset estimated intermediate quantities r are combined in different combinations. yoke multiplication operation to obtain N*(N‑1)/2 phase difference estimators; sum and average the N*(N‑1)/2 phase difference estimators to obtain the phase difference estimation result; The estimated frequency offset is obtained by calculating the phase difference estimation result. A frequency offset estimation method, system, storage medium and receiving device of a communication signal of the present invention are used for calculating a frequency offset estimation value.

Description

Frequency offset estimation method, system, storage medium and receiving device of communication signal

technical field

The present invention relates to the field of communication technologies, and in particular, to a frequency offset estimation method, system, storage medium and receiving device of a communication signal.

Background technique

In a wireless communication system, frequency synchronization is the premise and basis for correct data transmission. In general, the frequency offset of the received signal is mainly composed of carrier frequency offset and Doppler frequency offset. The carrier frequency offset is caused by the different frequencies of the receiver crystal oscillator and the transmitter crystal oscillator, and the Doppler frequency offset is formed by the relative movement between the transmitter and the receiver. These frequency offsets will add a time to the received signal. The variable phase rotation, which in turn leads to a decrease in the received signal-to-noise ratio, affects the communication quality. In order to obtain higher communication quality, it is necessary to estimate the frequency offset, and perform frequency tracking and compensation through automatic frequency control.

Common frequency offset estimation methods are estimated by inserting the preamble, pilot or cyclic prefix in the synchronization signal. The transmitter inserts a training sequence for frequency offset estimation into the synchronization signal, and when the receiver receives the synchronization signal, the autocorrelation method is used to extract the phase difference between the two identical sequences before and after, thereby performing frequency offset estimation.

In the process of realizing the present invention, the inventor found that the existing technology has at least the following problems.

In the case of poor communication conditions and low signal-to-noise ratio, since the synchronization signal is submerged by noise, it has a great influence on the statistical estimator used to extract the frequency offset, resulting in inaccurate estimation and large mean square error. Using the estimation result to perform frequency offset compensation on the received signal will not produce any gain, but will degrade the receiving performance.

Therefore, it is desirable to solve the problem of how to better estimate the frequency offset, so as to avoid the problem of performance degradation due to the use of the estimation result calculated by the autocorrelation method to perform frequency offset compensation on the received signal.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a frequency offset estimation method, system, storage medium and receiving device for a communication signal, which are used to solve how to better perform frequency offset estimation in the prior art, In order to avoid the problem of performance degradation due to the use of the estimation result calculated by the autocorrelation method to perform frequency offset compensation on the received signal.

In order to achieve the above purpose and other related purposes, the present invention provides a method for estimating frequency offset of a communication signal, comprising the following steps: receiving N transmission signals with a length of M sent by a transmitting end of the communication signal, and after the transmission signal is transmitted through a channel become a received signal with a length of M*N; perform a cross-correlation operation on the received signal and the transmitted signal to obtain N frequency offset estimated intermediate quantities r; perform different combinations of the N frequency offset estimated intermediate quantities r Conjugate multiplication operation to obtain N*(N-1)/2 phase difference estimators; sum and average the N*(N-1)/2 phase difference estimators to obtain the phase difference estimation result; The phase difference estimation result is calculated to obtain a frequency offset estimation value.

所述发射信号的功率已进行归一化为

In an embodiment of the present invention, the number of M transmission signals is expressed as

The power of the transmitted signal has been normalized to

所述N个频偏估计中间量r根据

计算，1≤j≤M，1≤i≤N。In an embodiment of the present invention, the received signal whose length is M*N is expressed as

The N frequency offset estimation intermediate quantities r are based on

Calculation, 1≤j≤M, 1≤i≤N.

In an embodiment of the present invention, the N*(N-1)/2 phase difference estimators are

计算频偏估计值f_d，f_s为采样率，θ为相位差估计结果。In an embodiment of the present invention, it also includes

Calculate the frequency offset estimation value f _d , where f _s is the sampling rate, and θ is the phase difference estimation result.

In order to achieve the above purpose, the present invention also provides a frequency offset estimation system for communication signals, comprising: a receiving module, a first computing module, a second computing module, a third computing module and a fourth computing module; the receiving module is used for Receive the N times the number of M transmission signals sent by the transmitting end of the communication signal, the transmission signals become M*N received signals after channel transmission; the first arithmetic module is used to combine the received signals with the transmitted signals The signal is subjected to cross-correlation operation to obtain N frequency offset estimated intermediate quantities r; the second operation module is used to perform different combinations of conjugate multiplication operations on the N frequency offset estimated intermediate quantities r to obtain N*(N -1)/2 phase difference estimators; the third operation module is used to sum and average the N*(N-1)/2 phase difference estimators to obtain a phase difference estimation result; the fourth The operation module is used for calculating the phase difference estimation result to obtain the frequency offset estimation value.

In order to achieve the above object, the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, implements any of the above methods for estimating frequency offset of a communication signal.

In order to achieve the above object, the present invention also provides a receiving device, comprising: a processor and a memory; the memory is used for storing a computer program; the processor is connected to the memory and is used for executing the computer program stored in the memory , so that the receiving apparatus executes any one of the above methods for estimating frequency offsets of communication signals.

Finally, the present invention also provides a frequency offset estimation system for a communication signal, including the above-mentioned communication signal receiving device and communication signal transmitting device; the communication signal transmitting device is used for transmitting N transmission signals of length M.

In an embodiment of the present invention, the communication signal receiving device is an antenna, an amplifier, a filter, a mixer, an analog-to-digital converter or a processor.

As described above, the method, system, storage medium and receiving device for frequency offset estimation of a communication signal of the present invention have the following beneficial effects: a frequency offset estimated value is obtained by calculating a frequency offset cross-correlation method; the frequency offset estimated value When applied to the frequency offset compensation of the received signal, it can improve the performance and increase the gain. In addition, when the signal conditions are good, a simplified algorithm can also be used to estimate the frequency offset faster. The simplified algorithm can reduce the amount of calculation and improve the synchronization speed.

Description of drawings

FIG. 1 is a flowchart of a method for estimating frequency offset of a communication signal according to an embodiment of the present invention;

FIG. 2 is a schematic diagram showing the relationship between the length of the transmitted signal and the received signal according to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing N frequency offset estimated intermediate quantities r obtained by performing a cross-correlation operation on the received signal and the transmitted signal according to an embodiment of the present invention;

4 is a schematic diagram showing N*(N-1)/2 phase difference estimators obtained by performing different combinations of conjugate multiplication operations on the N frequency offset estimation intermediate quantities r according to an embodiment of the present invention;

5 is a schematic diagram of residual frequency offset statistics of the 1kHz frequency offset cross-correlation method of the present invention in an embodiment;

FIG. 6 is a schematic diagram showing the residual frequency offset statistics of the 1kHz frequency offset autocorrelation method of the present invention in an embodiment;

FIG. 7 is a schematic diagram showing the residual frequency offset statistics of the 2kHz frequency offset cross-correlation method of the present invention in an embodiment;

FIG. 8 is a schematic diagram showing the residual frequency offset statistics of the 2kHz frequency offset autocorrelation method of the present invention in an embodiment;

FIG. 9 is a schematic diagram showing the residual frequency offset statistics of the 1kHz frequency offset cross-correlation method of the present invention in an embodiment;

FIG. 10 is a schematic diagram showing the residual frequency offset statistics of the 1kHz frequency offset autocorrelation method of the present invention in an embodiment;

FIG. 11 is a schematic structural diagram of a frequency offset estimation system for a communication signal according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a communication signal receiving apparatus according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of a frequency offset estimation system for a communication signal according to another embodiment of the present invention.

Component label description

111 Receiver module

112 The first operation module

113 Second operation module

114 The third operation module

115 Fourth arithmetic module

121 processors

122 memory

131 Communication signal receiving device

132 Communication signal transmitter

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other under the condition of no conflict.

It should be noted that the drawings provided in the following embodiments are only used to illustrate the basic concept of the present invention in a schematic way, so the drawings only show the components related to the present invention rather than the number, shape and number of components in actual implementation. For dimension drawing, the type, quantity and proportion of each component can be changed at will in actual implementation, and the component layout may also be more complicated.

The frequency offset estimation method, system, storage medium and receiving device of the communication signal of the present invention calculate and obtain the frequency offset estimation value based on the frequency offset cross-correlation method; the frequency offset estimation value can improve the performance when applied to the frequency offset compensation of the received signal , increase the gain.

As shown in FIG. 1 , in an embodiment, the method for estimating frequency offset of a communication signal of the present invention includes the following steps:

Step S11: Receive N times of M transmission signals sent by the transmitting end of the communication signal, and the transmission signals become M*N received signals after channel transmission.

所述发射信号包括但不限于2PSK(2PSK是相移键控的最简单的一种形式，它用两个初相相隔为180的载波来传递二进制信息，所以也被称为BPSK)、QPSK(正交相移键控(Quadrature Phase ShiftKeyin，QPSK)是一种数字调制方式。它分为绝对相移和相对相移两种)等。所述发射信号是已归一的信号。具体地，X_k中的k可表示为M*N，如k＝2*3时则M＝2，N＝3，表示为第3次发送的复信号

中的x₂，所述M*N个接收信号表示为

In an embodiment of the present invention, the N times the transmit signal with the number M is a normalized circularly modulated complex signal, and the normalized circularly modulated complex signal with a length of M can be expressed as

The transmission signal includes but is not limited to 2PSK (2PSK is the simplest form of phase shift keying, it uses two carriers with an initial phase interval of 180 to transmit binary information, so it is also called BPSK), QPSK ( Quadrature Phase Shift Keying (Quadrature Phase Shift Keyin, QPSK) is a digital modulation method. It is divided into absolute phase shift and relative phase shift) and so on. The transmitted signal is a normalized signal. Specifically, k in X _k can be expressed as M*N, for example, when k=2*3, M=2, N=3, which is expressed as the complex signal sent for the third time

x ₂ in , the M*N received signals are expressed as

As shown in FIG. 2 , in an embodiment, a transmit signal with a length of M is sent N times to obtain a received signal with a length of M*N after channel transmission.

Step S12: Perform a cross-correlation operation on the received signal and the transmitted signal to obtain N intermediate frequency offset estimates r.

所述N个频偏估计中间量r根据

计算，1≤j≤M，1≤i≤N。所述x_j ^*与x_j为复共轭关系。In an embodiment of the present invention, the received signal whose length is M*N is expressed as

The N frequency offset estimation intermediate quantities r are based on

Calculation, 1≤j≤M, 1≤i≤N. The x _j ^* and x _j are in a complex conjugate relationship.

Specifically, as shown in Figure 3,

Step S13: Perform different combinations of conjugate multiplication operations on the N intermediate frequency offset estimates r to obtain N*(N-1)/2 phase difference estimates.

其中所述r_j ^*与r_j为复共轭关系。In an embodiment of the present invention, the N*(N-1)/2 phase difference estimators are

The r _j ^* and r _j are in a complex conjugate relationship.

Specifically, as shown in Figure 4,

In general, step S13 needs to calculate N*(N-1)/2 r _i . When the SNR is high (compared to the case of worse signal quality), the simplified algorithm can reduce the number of _ri to be calculated, for example, only 2 ri can be calculated, so the amount of calculation can be reduced and the synchronization speed can be improved. Specifically, when the SNR is high, the simplified algorithm may perform a cross-correlation operation on the received signal and the transmitted signal in step S12, and only calculate one or two r values when N frequency offset estimation intermediate quantities r are obtained , for example to compute only r ₁ and r ₂ . Subsequent step S13 only needs to perform different combinations of conjugate multiplication operations on r ₁ and r ₂ to obtain a phase difference estimator.

Step S14, summing and averaging the N*(N-1)/2 phase difference estimates to obtain a phase difference estimation result.

求和，i<j，1≤j≤N，1≤i≤N，得到相位差估计结果。所述相位差估计结果

即为所有的θ_i,j的求和平均值。In an embodiment of the present invention, the N*(N-1)/2 phase difference estimators are

Sum, i<j, 1≤j≤N, 1≤i≤N, get the phase difference estimation result. The phase difference estimation result

That is, the summed average of all θ _i,j .

Step S15: Calculate the phase difference estimation result to obtain a frequency offset estimation value.

计算频偏估计值f_d，f_s为采样率，θ为相位差估计结果。In an embodiment of the present invention, it also includes

Calculate the frequency offset estimation value f _d , where f _s is the sampling rate, and θ is the phase difference estimation result.

As shown in FIG. 5 , in one embodiment, the residual frequency offset chart of the 1kHz frequency offset cross-correlation method is displayed; as shown in FIG. 6 , the residual frequency offset chart of the 1kHz frequency offset autocorrelation method is displayed. It can be seen from the figure that both methods can estimate the frequency offset. The residual frequency offset obtained by the method adopted in the present invention is smaller.

As shown in FIG. 7 , in an embodiment, the residual frequency offset statistics of the 2kHz frequency offset cross-correlation method are displayed; as shown in FIG. 8 , the residual frequency offset statistics of the 2kHz frequency offset autocorrelation method are displayed. It can be seen from the figure that the autocorrelation method has been unable to estimate the frequency offset, and the method of the present invention can estimate the frequency offset and reduce the residual frequency offset.

SNR：信噪比SIGNAL NOISERATIO。另外差分方式的互相关方法可以抵消信号的初始相位，提高估计精度。As shown in FIG. 9 , in one embodiment, the residual frequency offset statistics of the 1kHz frequency offset cross-correlation method is displayed; - the residual frequency offset statistics diagram of the 1kHz frequency offset autocorrelation method is shown in FIG. 10 . It can be seen from the figure that the autocorrelation method has been unable to estimate the frequency offset, and the method of the present invention can estimate the frequency offset and reduce the residual frequency offset. The difference between Figures 5 and 6 and Figures 9 and 10 is that the SNR (Signal to Noise Ratio) values are different. The SNR of Figures 5 and 6 is -10dB, and the SNR of Figures 9 and 10 is -20dB. The technical effect of the invention is that compared with the traditional communication equipment using the autocorrelation method, the estimated variance of the communication equipment using the cross-correlation method is theoretically smaller; in the case of training symbols of the same length, the theoretical variance is reduced to the original of

SNR: Signal-to-noise ratio SIGNAL NOISERATIO. In addition, the cross-correlation method of the differential mode can cancel the initial phase of the signal and improve the estimation accuracy.

As shown in FIG. 11 , in an embodiment, the frequency offset estimation system of the communication signal of the present invention includes a receiving module 111 , a first computing module 112 , a second computing module 113 , a third computing module 114 and a fourth computing module 115.

The receiving module 111 is configured to receive N transmit signals with a length of M sent by a communication signal transmitting end, and the transmit signals become received signals with a length of M*N after being transmitted through a channel.

所述发射信号包括但不限于QPSK(正交相移键控(Quadrature Phase Shift Keyin，QPSK)是一种数字调制方式。它分为绝对相移和相对相移两种)、2PSK(2PSK是相移键控的最简单的一种形式，它用两个初相相隔为180的载波来传递二进制信息，所以也被称为BPSK)等。具体地，X_k中的k可表示为M*N，如k＝2*3时则M＝2，N＝3，表示为第3次发送的复信号

中的x₂，所述长度为M*N的接收信号表示为

In an embodiment of the present invention, the N transmit signals with a length of M are normalized circularly modulated complex signals, and the normalized circularly modulated complex signals with a length of M can be expressed as

The transmission signal includes but is not limited to QPSK (Quadrature Phase Shift Keyin (QPSK) is a digital modulation method. It is divided into absolute phase shift and relative phase shift), 2PSK (2PSK is a phase shift The simplest form of shift keying, it uses two carriers with an initial phase interval of 180 to transmit binary information, so it is also called BPSK) and so on. Specifically, k in X _k can be expressed as M*N, for example, when k=2*3, M=2, N=3, which is expressed as the complex signal sent for the third time

x ₂ in , the received signal of length M*N is expressed as

In an embodiment, a transmit signal with a length of M is sent N times, and a received signal with a length of M*N is obtained after channel transmission.

The first operation module 112 is configured to perform a cross-correlation operation on the received signal and the transmitted signal to obtain N intermediate frequency offset estimates r.

所述N个频偏估计中间量r根据

计算，1≤j≤M，1≤i≤N。所述x_j ^*与x_j为复共轭关系。In an embodiment of the present invention, the received signals whose length is M* are expressed as

The N frequency offset estimation intermediate quantities r are based on

Calculation, 1≤j≤M, 1≤i≤N. The x _j ^* and x _j are in a complex conjugate relationship.

specifically,

The second operation module 113 is configured to perform different combinations of conjugate multiplication operations on the N intermediate frequency offset estimates r to obtain N*(N−1)/2 phase difference estimates.

其中所述r_j ^*与r_j为复共轭关系。In an embodiment of the present invention, the N*(N-1)/2 phase difference estimators are

The r _j ^* and r _j are in a complex conjugate relationship.

specifically,

The third operation module 114 is configured to sum and average the N*(N-1)/2 phase difference estimates to obtain a phase difference estimation result.

求和，i<j，1≤j≤N，1≤i≤N，得到相位差估计结果。所述相位差估计结果

即为所有的θ_i,j的求和平均值。In an embodiment of the present invention, the N*(N-1)/2 phase difference estimators are

Sum, i<j, 1≤j≤N, 1≤i≤N, get the phase difference estimation result. The phase difference estimation result

That is, the summed average of all θ _i,j .

The fourth operation module 115 is configured to calculate the phase difference estimation result to obtain a frequency offset estimation value.

计算频偏估计值f_d，f_s为采样率，θ为相位差估计结果。In an embodiment of the present invention, it also includes

Calculate the frequency offset estimation value f _d , where f _s is the sampling rate, and θ is the phase difference estimation result.

It should be noted that it should be understood that the division of each module of the above system is only a division of logical functions, and may be fully or partially integrated into a physical entity in actual implementation, or may be physically separated. And these modules can all be implemented in the form of software calling through processing elements; they can also all be implemented in hardware; some modules can also be implemented in the form of calling software through processing elements, and some modules can be implemented in hardware. For example, the x module may be a separately established processing element, or it may be integrated into a certain chip of the above-mentioned device to be implemented, in addition, it may also be stored in the memory of the above-mentioned device in the form of program code, and a certain processing element of the above-mentioned device Calls and executes the functions of the above x module. The implementation of other modules is similar. In addition, all or part of these modules can be integrated together, and can also be implemented independently. The processing element described here may be an integrated circuit with signal processing capability. In the implementation process, each step of the above-mentioned method or each of the above-mentioned modules can be completed by an integrated logic circuit of hardware in the processor element or an instruction in the form of software.

For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more specific integrated circuits (Application Specific Integrated Circuit, ASIC for short), or one or more microprocessors ( Digital Singnal Processor, DSP for short), or one or more Field Programmable Gate Arrays (Field Programmable Gate Array, receiving device for short), etc. For another example, when one of the above modules is implemented in the form of processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (Central Processing Unit, CPU for short) or other processors that can call program codes. For another example, these modules can be integrated together and implemented in the form of a system-on-a-chip (SOC for short).

In an embodiment of the present invention, the present invention further includes a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, implements any of the above-mentioned frequency offset estimation methods for communication signals.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by hardware related to computer programs. The aforementioned computer program may be stored in a computer-readable storage medium. When the program is executed, the steps including the above method embodiments are executed; and the foregoing storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

As shown in FIG. 10, in an embodiment, the receiving apparatus of the present invention includes: a processor 121 and a memory 122; the memory 122 is used for storing computer programs; the processor 121 is connected to the memory 122, and is used for The computer program stored in the memory 122 is executed, so that the receiving apparatus executes any one of the frequency offset estimation methods for communication signals.

Specifically, the memory 122 includes various media that can store program codes, such as ROM, RAM, magnetic disk, U disk, memory card, or optical disk.

Preferably, the processor 121 may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU for short), a network processor (Network Processor, NP for short), etc.; it may also be a digital signal processor (Digital Signal Processor, DSP for short), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (Receiver for short), or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

As shown in FIG. 11 , in an embodiment, the frequency offset estimation system of a communication signal of the present invention includes the above-mentioned communication signal receiving device 131 and communication signal transmitting device 132 . The communication signal transmitting device 132 is configured to transmit N times of M transmission signals.

In an embodiment of the present invention, the communication signal receiving device includes, but is not limited to, an antenna, an amplifier, a filter, a mixer, an analog-to-digital converter, or a processor.

To sum up, the frequency offset estimation method, system, storage medium and receiving device of the present invention are based on the frequency offset cross-correlation method to calculate and obtain the frequency offset estimation value; the frequency offset estimation value is applied to the frequency offset compensation of the received signal can improve performance and increase gain. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can make modifications or changes to the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

Claims (7)

1. A method of frequency offset estimation of a communication signal, comprising the steps of:

receiving N transmitting signals with the length of M sent by a communication signal transmitting end, wherein the transmitting signals become receiving signals with the length of M x N after being transmitted through a channel; the transmission signal with the length M is represented as

The power of the transmitted signal has been normalized

1≤k≤M*N；

Performing cross-correlation operation on the received signal and the transmitted signal to obtain N frequency offset estimation intermediate quantities r; the received signal with length M x N is expressed as

The N frequency offset estimation intermediate quantities r are based on

Calculating that j is more than or equal to 1 and less than or equal to M, i is more than or equal to 1 and less than or equal to N;

carrying out conjugate multiplication operation of different combinations on the N frequency offset estimation intermediate quantities r to obtain N x (N-1)/2 phase difference estimation quantities; the N x (N-1)/2 phase difference estimator is

i<j，1≤j≤N，1≤i≤N；

Averaging the N x (N-1)/2 phase difference estimators to obtain a phase difference estimation result;

and calculating the phase difference estimation result to obtain a frequency offset estimation value.

2. The method of frequency offset estimation of a communication signal of claim 1, further comprising estimating a frequency offset based on

Calculating frequency deviation estimated value f _d ，f _s To sample rate, θ is the phase difference estimation result.

3. A system for frequency offset estimation of a communication signal, comprising: the device comprises a receiving module, a first operation module, a second operation module, a third operation module and a fourth operation module;

the receiving module is used for receiving N transmitting signals with the length of M sent by a communication signal transmitting end, and the transmitting signals become receiving signals with the length of M x N after being transmitted through a channel; the transmission signal with the length M is represented as

The power of the transmitted signal has been normalized

1≤k≤M*N；

The first operation module is used for performing cross-correlation operation on the received signal and the transmitted signal to obtain N frequency offset estimation intermediate quantities r; the received signal with length M x N is expressed as

The N frequency offset estimation intermediate quantities r are based on

Calculating that j is more than or equal to 1 and less than or equal to M, i is more than or equal to 1 and less than or equal to N;

the second operation module is used for carrying out conjugate multiplication operation of different combinations on the N frequency offset estimation intermediate quantities r to obtain N x (N-1)/2 phase difference estimators; the N x (N-1)/2 phase difference estimator is

i<j，1≤j≤N，1≤i≤N；

The third operation module is used for averaging the N x (N-1)/2 phase difference estimators to obtain a phase difference estimation result;

and the fourth operation module is used for calculating the phase difference estimation result to obtain a frequency offset estimation value.

4. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out a method of frequency offset estimation of a communication signal according to any one of claims 1 to 2.

5. A communication signal receiving apparatus, comprising: a processor and a memory;

the memory is used for storing a computer program;

the processor is coupled to the memory and is configured to execute the computer program stored in the memory to cause the communication signal receiving apparatus to perform the method of frequency offset estimation of a communication signal according to any of claims 1 to 2.

6. A system for frequency offset estimation of a communication signal, comprising the communication signal receiving apparatus and the communication signal transmitting apparatus of claim 5; the communication signal transmitting device is used for transmitting N transmitting signals with the length of M.

7. The system for frequency offset estimation of a communication signal of claim 6, wherein said communication signal receiving means is an antenna, an amplifier, a filter, a mixer, an analog-to-digital converter, or a processor.

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