WO2018068365A1 - Doppler frequency offset estimation method and device based on millimeter wave mimo system - Google Patents

Abstract

Embodiments of the present application provide a Doppler frequency offset estimation method and device based on a millimeter wave MIMO system. The method comprises: building a maximum likelihood estimation model for a Doppler frequency offset according to signals received by a receiving end in a millimeter wave MIMO system; determining a solution expression of the Doppler frequency offset according to the maximum likelihood estimation model; and estimating the Doppler frequency offset according to the solution expression. Compared with the prior art, by applying the embodiments of the present application, the Doppler frequency offset of the millimeter wave MIMO system can be estimated.

Description

Doppler frequency offset estimation method and device based on millimeter wave MIMO system

The present application claims priority to Chinese Patent Application No. 201610887151.2, entitled "A Doppler Frequency Offset Estimation Method and Apparatus Based on Millimeter Wave MIMO System", which is filed on October 11, 2016. The entire contents are incorporated herein by reference.

Technical field

The present application relates to the field of wireless communication technologies, and in particular, to a Doppler frequency offset estimation method and apparatus based on a millimeter wave MIMO system.

Background technique

The channel involved in a wireless communication system is typically a multipath time-varying fading channel whose amplitude and phase of the received signal change over time. The speed of the fading channel changes depends on the channel Doppler frequency offset. The larger the Doppler frequency offset, the faster the channel changes. This requires real-time estimation of Doppler frequency offset and dynamic adjustment of system parameters based on Doppler shift to achieve optimal reception performance. Wherein, the Doppler frequency offset refers to a change in frequency caused by the movement of the receiving end or the transmitting end. The estimation of Doppler frequency offset has been widely used in the selection, optimization and adaptive methods of system parameters.

At present, Doppler frequency offset estimation methods mainly include estimation based on channel autocorrelation characteristics, estimation based on level pass rate, estimation based on switch diversity, and the like. However, each estimation method is only applied to the corresponding application scenario, and the application range is limited. For example, the frequency offset estimation method based on the real-time frequency synchronization and phase offset automatic tracking of the 60 GHz CS-OFDM MIMO system is only applicable to the scene targeted by the local oscillator, that is, the scene without the direct path. The iterative frequency offset estimation method for flat fading is only for the scene of the flat fading channel.

Since each estimation method is only applicable to its corresponding application scenario, the above estimation methods cannot be applied to a millimeter wave MIMO (Multiple Input Multiple Output) system, and the prior art does not The Doppler frequency offset estimation method for millimeter-wave MIMO systems, therefore, how to estimate the Doppler frequency offset of millimeter-wave MIMO systems is an urgent problem to be solved.

Summary of the invention

The purpose of embodiments of the present application is to provide a Doppler frequency offset based on a millimeter wave MIMO system. An estimation method and apparatus for estimating a Doppler shift of a millimeter wave MIMO system.

To achieve the above objective, an embodiment of the present application provides a Doppler frequency offset estimation method based on a millimeter wave MIMO system, including:

Constructing a maximum likelihood estimation model for Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system;

Determining an expression of the Doppler frequency offset according to the maximum likelihood estimation model;

The Doppler frequency offset is estimated according to the solution expression.

Optionally, the maximum likelihood estimation model for the Doppler frequency offset is constructed according to the signal received by the receiving end in the millimeter wave MIMO system, including:

Determining a beamforming weight vector w(θ) according to a signal to noise ratio SINR;

Constructing a cost function (f _d , θ _p , β _p ) for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector, wherein , f _d is the Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is the position angle of the mobile receiving end relative to the transmitting end, and β _p is the fading loss of the mobile receiving end;

A maximum likelihood estimation model (f _d , θ) for the Doppler shift is constructed based on the cost function and the beamforming weight vector.

Optionally,

为a_T(θ_p)的转置矩阵，a_T(θ_p)为移动发射端的方向向量，

λ为 发射信号的波长，n_T为发射端的发射天线数，n_R为接收端的接收天线数，d_T为发射端天线各元素之间的距离，d_R为接收端天线各元素之间的距离，R_in为干扰噪声相关矩阵，

σ为噪音正态分布函数，

为接收天线的单位矩阵，θ_i为第i个静止接收端相对于发射端的位置角度，β_i为第i个静止接收端的衰落损耗，L表示静止接收端个数，

为a_T(θ_i)的转置矩阵，a_T(θ_i)为第i个静止发射端的方向向量，

a_R(θ_i)为第i个静止接收端的方向向量， Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

Determined beamforming weight vector

为R_in的逆矩阵；Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _in ;

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end;

Constructed cost function for f _d , θ _p , β _p

为a_T(θ)的转置矩阵，a_T(θ)为发射端的方向向量，

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

Constructed Maximum Likelihood Estimation Model for Doppler Frequency Offset

为a_T(θ)的共轭转置矩阵。among them,

A conjugate transpose matrix of a _T (θ).

为：Optionally, the determined expression of the Doppler frequency offset is determined according to the maximum likelihood estimation model

for:

among them,

To achieve the above objective, the embodiment of the present application further provides a Doppler frequency offset estimation apparatus based on a millimeter wave MIMO system, including:

Constructing a module for constructing a maximum likelihood estimation model for Doppler frequency offset according to a signal received by a receiving end in a millimeter wave MIMO system;

a determining module, configured to determine a solution expression of the Doppler frequency offset according to the maximum likelihood estimation model;

And an estimation module, configured to estimate the Doppler frequency offset according to the solution expression.

Optionally, the building module includes:

a first determining subunit, configured to determine a beamforming weight vector w(θ) according to a signal to noise ratio SINR;

a first building subunit for constructing a cost function (f _d for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector; θ _p , β _p ), wherein f _d is a Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is a position angle of the mobile receiving end relative to the transmitting end, and β _p is a fading loss of the mobile receiving end;

And a second construction subunit, configured to construct a maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset according to the cost function and the beamforming weight vector.

Optionally,

为a_T(θ_p)的转置矩阵，a_T(θ_p)为移动发射端的方向向量，

λ为发射信号的波长，n_T为发射端的发射天线数，n_R为接收端的接收天线数，d_T为发射端天线各元素之间的距离，d_R为接收端天线各元素之间的距离，R_in为干扰噪声相关矩阵，

σ为噪音正态分布函数，

为接收天线的单位矩阵，θ_i为第i个静止接收端相对于发射端的位置角度，β_i为第i个静止接收端的衰落损耗，L表示静止接收端个数，

为a_T(θ_i)的转置矩阵，a_T(θ_i)为第i个静止发射端的方向向量，

a_R(θ_i)为第i个静止接收端的方向向量，

Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

Determined beamforming weight vector

为R_in的逆矩阵； Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _in ;

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end;

Constructed cost function for f _d , θ _p , β _p

为a_T(θ)的转置矩阵，a_T(θ)为发射端的方向向量，

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

Constructed Maximum Likelihood Estimation Model for Doppler Frequency Offset

为a_T(θ)的共轭转置矩阵。among them,

A conjugate transpose matrix of a _T (θ).

为：Optionally, the solution expression determined by the determining module

for:

among them,

The present application also provides an electronic device comprising: a housing, a processor, a memory, a circuit board, and a power supply circuit, wherein the circuit board is disposed inside a space enclosed by the housing, and the processor and the memory are disposed on the circuit board; a power circuit for powering each circuit or device; a memory for storing executable program code; the processor running a program corresponding to the executable program code by reading executable program code stored in the memory for execution of the program The Doppler frequency offset estimation method based on the millimeter wave MIMO system provided by the embodiment is applied.

An embodiment of the present application provides an application for executing the application at runtime The Doppler frequency offset estimation method based on the millimeter wave MIMO system provided by the embodiment is provided.

The embodiment of the present application provides a storage medium for storing executable program code, and the executable program code is executed to perform a Doppler frequency offset based on a millimeter wave MIMO system provided by an embodiment of the present application. Estimation method. The Doppler frequency offset estimation method and apparatus based on the millimeter wave MIMO system provided by the embodiment of the present application can realize the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

DRAWINGS

In order to more clearly illustrate the embodiments of the present application and the technical solutions of the prior art, the following description of the embodiments and the drawings used in the prior art will be briefly introduced. Obviously, the drawings in the following description are only Some embodiments of the application may also be used to obtain other figures from those of ordinary skill in the art without departing from the scope of the invention.

1 is a schematic diagram of a beamforming structure of a millimeter wave MIMO system;

2 is a schematic flowchart of a Doppler frequency offset estimation method based on a millimeter wave MIMO system according to an embodiment of the present application;

3 is a schematic flowchart of a process of constructing a maximum likelihood estimation model for Doppler frequency offset in a Doppler frequency offset estimation method based on a millimeter wave MIMO system according to an embodiment of the present application;

4 is a schematic structural diagram of a Doppler frequency offset estimation apparatus based on a millimeter wave MIMO system according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of a building block in a Doppler frequency offset estimating apparatus based on a millimeter wave MIMO system according to an embodiment of the present application.

detailed description

In order to make the objects, technical solutions, and advantages of the present application more comprehensible, the present application will be further described in detail below with reference to the accompanying drawings. It is apparent that the described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

In order to estimate the Doppler frequency offset of the millimeter wave MIMO system, the embodiment of the present application provides a Doppler frequency offset estimation method and apparatus based on a millimeter wave MIMO system, which will be described in detail below.

Incidentally, the structure of the millimeter wave beamforming MIMO system shown in Figure 1 can be assumed that the MIMO system is a millimeter wave frequency band occupied by the wave 28GH _Z, is selected transmitter n _T n _T transmit antennas and a transmission frequency gain The receiving end uses n _R receiving antennas and n _R receiving frequency gains.

The specific working process of the millimeter wave MIMO system is as follows: each transmission symbol of the transmitting end is processed by the baseband signal to perform an RF link, and then the transmission precoding is performed between the transmission symbols of each channel, and after the encoding is completed, it becomes a transmission signal and is sent to the antenna array. After transmitting, the transmitted signal is received by the receiving antenna array after passing through the millimeter wave MIMO channel, and the received signal is obtained after the operation opposite to the transmitting end.

In practical applications, each uniform linear array of the transmitting end may include 8 horizontal elements, and each uniform linear array of the receiving end may include 4 horizontal elements, and the beam half width of the antenna aperture of the transmitting end may be about 10° horizontally. Vertically 20°, the beam half-width of the antenna aperture at the receiving end can be approximately 25° horizontal and 60° vertical. For RF gain, the transmit end can be 21dBi and the receive end can have an RF gain of 8dBi.

As shown in FIG. 2, a Doppler frequency offset estimation method based on a millimeter wave MIMO system provided by an embodiment of the present application may include the following steps:

S210. Construct a maximum likelihood estimation model for Doppler frequency offset according to a signal received by a receiving end in a millimeter wave MIMO system.

It can be understood that in order to realize the estimation of the Doppler frequency offset in the millimeter wave MIMO system, the maximum likelihood estimation model for the Doppler frequency offset can be constructed according to the signal received by the receiving end in the millimeter wave MIMO system.

S220. Determine a solution expression of the Doppler frequency offset according to the maximum likelihood estimation model.

Specifically, in order to reduce the complexity of the algorithm, the maximum likelihood estimation model may be simplified to determine a solution expression of the Doppler frequency offset. For example, the maximum likelihood estimation model can be simplified into a solution expression in the form of a two-dimensional FFT (Fast Fourier Transform) solution.

S230. Estimate the Doppler frequency offset according to the solution expression.

Specifically, after determining the expression of the Doppler shift, the dichotomy and the gradient can be used. The method of lowering the method, solving the solution expression, obtaining the estimated value of the Doppler frequency offset, and then realizing the estimation of the Doppler frequency offset.

Further, as shown in FIG. 3, a process of constructing a maximum likelihood estimation model for Doppler frequency offset according to a signal received by a receiving end in a millimeter wave MIMO system may include the following steps:

S310, determining a beamforming weight vector w(θ) according to a signal to noise ratio SINR;

Specifically, the expression of the signal to noise ratio SINR is:

为a_T(θ_p)的转置矩阵，a_T(θ_p)为移动发射端的方向向量，

λ为发射信号的波长，n_T为发射端的发射天线数，n_R为接收端的接收天线数，d_T为发射端天线各元素之间的距离，d_R为接收端天线各元素之间的距离，R_in为干扰噪声相关矩阵，

σ为噪音正态分布函数，

为接收天线的单位矩阵，θ_i为第i个静止接收端相对于发射端的位置角度，β_i为第i个静止接收端的衰落损耗，L表示静止接收端个数，

为a_T(θ_i)的转置矩阵，a_T(θ_i)为第i个静止发射端的方向向量，

a_R(θ_i)为第i个静止接收端的方向向量，

Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

并且波束成形权重向量还满足w^Ha_R(θ)＝1_，进而可以推导出波束成形权重向量的表达式。In order to construct a maximum likelihood estimation model for Doppler shift, it is necessary to maximize the signal-to-noise ratio. If the signal-to-noise ratio is to be maximized, it must be satisfied.

And the beamforming weight vector also satisfies w ^H a _R (θ)=1 _, and the expression of the beamforming weight vector can be derived.

其中，a_R(θ)为接收端的方向向量，

为R_in的逆矩阵。Therefore, according to the above conditions, the determined beamforming weight vector

Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _in .

S320. Construct a cost function (f _d , θ _p , β _p ) for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector. Where f _d is the Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is the position angle of the mobile receiving end relative to the transmitting end, and β _p is the fading loss of the mobile receiving end;

Specifically, the expression of the received signal y(n) at the receiving end is:

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end;

Then, constructing a cost function (f _d , θ _p , β _p ) for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector. ;

Specifically, the determined final expression for f _d, θ _p, β _p cost function _{(f d, θ p, β} p) as:

为a_T(θ)的转置矩阵，a_T(θ)为发射 端的方向向量，

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

S330. Construct a maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset according to the cost function and the beamforming weight vector;

Specifically, first, the first equation is obtained by using a β minimization cost function (f _d , θ _p , β _p );

Specifically, the obtained first equation is:

为a_T(θ)的共轭转置矩阵；among them,

a conjugate transposed matrix of a _T (θ);

Then, the first equation is substituted into the cost function (f _d , θ _p , β _p ) and then minimized to obtain a first cost function (f _d , θ) ₁ ;

Specifically, the expression of the obtained first cost function (f _d , θ) ₁ is:

Then, the determined beamforming weight vector w(θ) is substituted into the first cost function (f _d , θ) ₁ to obtain a second cost function (f _d , θ) ₂ ;

Specifically, the expression of the obtained second cost function (f _d , θ) ₂ is:

Finally, the second cost function (f _d , θ) ₂ is simplified to obtain a maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset;

That is, the constructed maximum likelihood estimation model (f _d , θ) for the Doppler shift is:

Further, according to the constructed maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset, the solution expression of the Doppler frequency offset can be determined.

则(f_d,θ)中的数学公式

转换为第一表达式G(n)₁为：Specifically,

Then the mathematical formula in (f _d , θ)

Convert to the first expression G(n) ₁ is:

Substituting the expressions of a _T (θ _p ) and a _R (θ _R ) into the first expression G(n) ₁ , the first expression G(n) ₁ can be converted into the second expression G(n) ₂ is:

的结果中不包括指数部分的部分。Where r _k (n) is

The part of the index part is not included in the results.

则第二表达式G(n)₂可以转换为第三表达式G(n)₃为：make

Then the second expression G(n) ₂ can be converted into the third expression G(n) ₃ as:

Expanding the third expression G(n) ₃ , we can get the fourth expression G(n) ₄ :

By arranging the fourth expression G(n) ₄ , the general expression of G(n) can be obtained as follows:

以及

因此

If the distance between two adjacent antennas of the MIMO transmitting end and the receiving end is considered to be one-half of the wavelength of the transmitted signal,

as well as

therefore

对第四表达式G(n)₄进行简化，可以得到第五表达式G(n)₅为：use

To simplify the fourth expression G(n) ₄ , the fifth expression G(n) ₅ can be obtained as:

时，G(n)的一般表达式为：Therefore, when

When G(n)'s general expression is:

To get the expected value of the general expression of G(n), you can get the following expression:

则E{G(n)}可以化简为如下形式：make

Then E{G(n)} can be reduced to the following form:

Finally, the reduced expression of E{G(n)} is substituted into the maximum likelihood estimation model (f _d , θ) for Doppler frequency offset and simplified to determine the Doppler frequency offset. Solution expression

为：The solution expression of the determined Doppler frequency offset

for:

It can be understood that for parameter estimation problems, CRLB (Cramer Rao Low Bound) determines a lower bound for the variance of any unbiased estimator. That is, since it is impossible to find an unbiased estimator whose variance is less than the lower limit, a criterion is provided for comparing the performance of the unbiased estimator. Moreover, this lower bound can be gradually reached when the unbiased estimator does not reach CRLB.

In order to measure the Doppler frequency offset f _d , the position angle θ _{p of the} mobile receiving end relative to the transmitting end, and the estimation of the fading loss β _p of the mobile receiving end, the CRLB of these three parameters is derived.

将v(n)简化成v，因此接收信号y(n)的表达式将会变成y＝s+n。First, the expression appearing in the received signal y(n) is represented by the signal term _s

Simplify v(n) to v, so the expression of the received signal y(n) will become y=s+n.

The received signal y with a time period of n to n+N-1 is composed of a sample vector, which can be expressed as: y=[y ^T (n), y ^T (n+1),..., y ^T (n+N-1) )].

和

表示，则将所有待估计参数用向量的形式表示为：

The fading loss β _{p of the} mobile receiving end is regarded as the real part and the imaginary part form, respectively

with

Representation, then all the parameters to be estimated are expressed in the form of vectors:

Assume that the noise samples v(n) to v(n+N-1) are uncorrelated and ignore the effects of interference. Refer to the FlI (Fisher Information Matrix) for the promotion of Slepian-Bangs. Formula, you can get the Fisher information matrix about the estimated vector Ω, as follows:

among them

是n_R×4的矩阵，

是4×n_R的矩阵，

Is a matrix of n _R ×4,

Is a matrix of 4 × n _R ,

Among them, the expressions of □ _R and □ _T are:

Compared with the prior art, the application of the embodiment of the present application achieves the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

As shown in FIG. 4, the embodiment of the present application further provides a Doppler frequency offset estimation apparatus based on a millimeter wave MIMO system, including:

The constructing module 410 is configured to construct a maximum likelihood estimation model for the Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system;

a determining module 420, configured to determine a solution expression of the Doppler frequency offset according to the maximum likelihood estimation model;

The estimation module 430 is configured to estimate the Doppler frequency offset according to the solution expression.

Further, as shown in FIG. 5, the building module 410 may include:

a first determining subunit 510, configured to determine a beamforming weight vector w(θ) according to a signal to noise ratio SINR;

Construction of a first sub-unit 520, a receiving end according to the millimeter wave signal y received MIMO system (n) and the beamforming weight vector to construct a cost function (f _d for f _d, θ _p, βp and θ _p , β _p ), wherein f _d is a Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is a position angle of the mobile receiving end relative to the transmitting end, and β _p is a fading loss of the mobile receiving end;

The second construction subunit 530 is configured to construct a maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset according to the cost function and the beamforming weight vector.

Further, the signal-to-noise ratio (SINR) according to the first determining sub-unit 510 may be

为a_T(θ_p)的转置矩阵，a_T(θ_p)为移动发射端的方向向量，

λ为发射信号的波长，n_T为发射端的发射天线数，n_R为接收端的接收天线数，d_T为发射端天线各元素之间的距离，d_R为接收端天线各元素之间的距离，R_in为干扰噪声相关矩阵，

σ为噪音正态分布函数，

为接收天线的单位矩阵，θ_i为第i个静止接收端相对于发射端的位置角度，β_i为第i个静止接收端的衰落损耗，L表示静止接收端个数，

为a_T(θ_i)的转置矩阵，a_T(θ_i)为第i个静止发射端的方向向量，

a_R(θ_i)为第i个静止接收端的方向向量，

Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

Beamforming weight vector determined by the first determining subunit 510

为R_in的逆矩阵_。 Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _{in .}

The first receiving subunit 520 receives a signal received by the receiving end in the millimeter wave MIMO system. The expression of y(n) can be:

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end;

The cost function (f _d , θ _p , β _p ) for f _d , θ _p , β _p constructed by the first construction subunit 520 is:

为a_T(θ)的转置矩阵，a_T(θ)为发射端的方向向量，

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

其中，

为a_T(θ)的共轭转置矩阵。The maximum likelihood estimation model (f _d , θ) for the Doppler shift is constructed by the second construction subunit 530 is:

among them,

A conjugate transpose matrix of a _T (θ).

可以为：Further, the solution expression determined by the determination module 420 is

Can be:

among them,

Compared with the prior art, the application of the embodiment of the present application achieves the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

The embodiment of the present application further provides an electronic device, including: a housing, a processor, a memory, a circuit board, and a power supply circuit, wherein the circuit board is disposed inside the space enclosed by the housing, and the processor and the memory are disposed on the circuit board. The power circuit is used to power each circuit or device; the memory is used to store executable program code; the processor is shipped by reading executable program code stored in the memory And a program corresponding to the executable program code for performing the Doppler frequency offset estimation method based on the millimeter wave MIMO system provided by the embodiment of the present application, wherein the Doppler frequency offset estimation based on the millimeter wave MIMO system Methods can include:

Constructing a maximum likelihood estimation model for Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system;

Determining an expression of the Doppler frequency offset according to the maximum likelihood estimation model;

The Doppler frequency offset is estimated according to the solution expression.

Compared with the prior art, the application of the embodiment of the present application achieves the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

The embodiment of the present application provides an application program for performing a Doppler frequency offset estimation method based on a millimeter wave MIMO system provided by an embodiment of the present application at runtime. The Doppler frequency offset estimation method based on the millimeter wave MIMO system may include:

Constructing a maximum likelihood estimation model for Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system;

Determining an expression of the Doppler frequency offset according to the maximum likelihood estimation model;

The Doppler frequency offset is estimated according to the solution expression.

Compared with the prior art, the application of the embodiment of the present application achieves the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

The embodiment of the present application provides a storage medium for storing executable program code, which is executed to execute a millimeter wave MIMO system-based Doppler frequency offset estimation method provided by an embodiment of the present application. The Doppler frequency offset estimation method based on the millimeter wave MIMO system may include:

Constructing a maximum likelihood estimation model for Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system;

Determining an expression of the Doppler frequency offset according to the maximum likelihood estimation model;

The Doppler frequency offset is estimated according to the solution expression.

Compared with the prior art, the application of the embodiment of the present application achieves the estimation of the Doppler frequency offset of the millimeter wave MIMO system.

It should be noted that, in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply such entities or operations. There is any such actual relationship or order between them. Furthermore, the term "comprises" or "comprises" or "comprises" or any other variations thereof is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that comprises a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

The various embodiments in the present specification are described in a related manner, and the same or similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus, the electronic device, the application, and the storage medium embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

The various embodiments in the present specification are described in a related manner, and the same or similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

The above is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc., which are made within the spirit and principles of the present application, should be included in the present application. Within the scope of protection.

Claims (11)

A Doppler frequency offset estimation method based on millimeter wave MIMO system, characterized in that it comprises: Constructing a maximum likelihood estimation model for Doppler frequency offset according to the signal received by the receiving end in the millimeter wave MIMO system; Determining an expression of the Doppler frequency offset according to the maximum likelihood estimation model; The Doppler frequency offset is estimated according to the solution expression. The method according to claim 1, wherein the maximum likelihood estimation model for Doppler frequency offset is constructed according to a signal received by a receiving end in a millimeter wave MIMO system, comprising: Determining a beamforming weight vector w(θ) according to a signal to noise ratio SINR; Constructing a cost function (f _d , θ _p , β _p ) for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector, wherein , f _d is the Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is the position angle of the mobile receiving end relative to the transmitting end, and β _p is the fading loss of the mobile receiving end; A maximum likelihood estimation model (f _d , θ) for the Doppler shift is constructed based on the cost function and the beamforming weight vector. The method of claim 2 wherein:

Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

Determined beamforming weight vector

Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _in ;

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end; Constructed cost function for f _d , θ _p , β _p

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

Constructed Maximum Likelihood Estimation Model for Doppler Frequency Offset

among them,

A conjugate transpose matrix of a _T (θ). The method according to claim 3, wherein the determined expression of the Doppler shift is determined according to the maximum likelihood estimation model

for:

among them,

A Doppler frequency offset estimation apparatus based on a millimeter wave MIMO system, comprising: Constructing a module for constructing a maximum likelihood estimation model for Doppler frequency offset according to a signal received by a receiving end in a millimeter wave MIMO system; a determining module, configured to determine a solution expression of the Doppler frequency offset according to the maximum likelihood estimation model; And an estimation module, configured to estimate the Doppler frequency offset according to the solution expression. The device according to claim 5, wherein the building module comprises: a first determining subunit, configured to determine a beamforming weight vector w(θ) according to a signal to noise ratio SINR; a first building subunit for constructing a cost function (f _d for f _d , θ _p , β _p according to the signal y(n) received by the receiving end in the millimeter wave MIMO system and the beamforming weight vector; θ _p , β _p ), wherein f _d is a Doppler frequency offset generated by the mobile receiving end relative to the transmitting end, θ _p is a position angle of the mobile receiving end relative to the transmitting end, and β _p is a fading loss of the mobile receiving end; And a second building subunit, configured to construct a maximum likelihood estimation model (f _d , θ) for the Doppler frequency offset according to the cost function and the beamforming weight vector. The device of claim 6 wherein:

Where w(θ) is the beamforming weight vector, θ is the position angle of the receiving end relative to the transmitting end, H is the channel matrix, x(n) is the matrix of the transmitting signal of the transmitting end, and a _R (θ _p ) is the mobile receiving end Direction vector,

Is a _T (θ _p) of the transposed matrix, a _T (θ _p) of the emission direction of the vector is a mobile terminal,

λ is the wavelength of the transmitted signal, n _T is the number of transmitting antennas at the transmitting end, n _R is the number of receiving antennas at the receiving end, d _T is the distance between the elements of the transmitting end antenna, and d _R is the distance between the elements of the receiving end antenna , R _in is the interference noise correlation matrix,

σ is the noise normal distribution function,

For the unit matrix of the receiving antenna, θ _i is the position angle of the i-th stationary receiving end with respect to the transmitting end, β _i is the fading loss of the i-th stationary receiving end, and L represents the number of stationary receiving ends,

Is a _T (θ _i) a transposed matrix, a _T (θ _i) is the i th direction vector stationary transmitting end,

a _R (θ _i ) is the direction vector of the ith stationary receiving end,

Determined beamforming weight vector

Where a _R (θ) is the direction vector of the receiving end,

Is the inverse matrix of R _in ;

Where n represents the symbol of the transmitted signal at the transmitting end, N represents the total number of symbols transmitted by the transmitting end, and v(n) is a matrix of noise at the receiving end; Constructed cost function for f _d , θ _p , β _p

Where β is the fading loss at the receiving end,

It is a _T (θ) of the transposed matrix, a _T (θ) of a direction vector of the transmitting end,

Constructed Maximum Likelihood Estimation Model for Doppler Frequency Offset

among them,

A conjugate transpose matrix of a _T (θ). The apparatus according to claim 7, wherein the determination expression determined by the determining module

for:

among them,

An electronic device, comprising: a housing, a processor, a memory, a circuit board, and a power supply circuit, wherein the circuit board is disposed inside the space enclosed by the housing, and the processor and the memory are disposed on the circuit board; a circuit for powering individual circuits or devices; a memory for storing Executing the program code; the processor executing the executable program code by reading the executable program code stored in the memory for performing the Doppler frequency offset based on the millimeter wave MIMO system according to any one of claims 1-4 Estimation method. An application program for performing the millimeter wave MIMO system-based Doppler frequency offset estimation method according to any one of claims 1 to 4 at runtime. A storage medium, characterized in that the storage medium is for storing executable program code, the executable program code being executed to perform the Doppler based on a millimeter wave MIMO system according to any one of claims 1-4 Le frequency offset estimation method.

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