Antenna phase error correction method, device, base station and storage medium

Abstract

The present application relates to a method, apparatus, computer device, storage medium, and computer program product for antenna phase error correction. The method comprises: obtaining positioning signals of the same terminal at different locations, obtaining a channel frequency domain response matrix of a wireless channel based on the positioning signals; obtaining a delay power spectrum estimate for each channel based on the channel frequency domain response matrix; determining a direct path component in the delay power spectrum estimate; obtaining an antenna phase error based on the direct path component, and correcting the antenna phase error based on the antenna phase error. This method can be applied in multipath environments, is less costly, and, compared to self-correction methods, has low computational complexity and is highly practical.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a method, device, base station and storage medium for correcting antenna phase errors. Background Art

[0002] When positioning a terminal, the positioning technologies can be divided into the following categories according to the measurement quantities used for positioning: time of arrival positioning, time difference of arrival positioning, and angle of arrival positioning.

[0003] In arrival angle positioning, high time synchronization accuracy is required for the base station's array antenna and radio frequency channel. The correction coefficient of the radio frequency channel can be quickly measured in a laboratory environment. The array antenna is affected by factors such as mutual coupling between array elements, array element position error, and array element radiation pattern error, and exhibits different phase errors at different incident angles.

[0004] In traditional antenna phase error correction, complex measurements are required in a microwave anechoic chamber to obtain phase error compensation parameters, which is time-consuming and labor-intensive, and is not conducive to large-scale deployment and application. Summary of the Invention

[0005] Based on this, it is necessary to provide a method, device, base station, computer-readable storage medium and computer program product for antenna phase error correction using actual positioning signals to address the above technical problems.

[0006] In a first aspect, the present application provides a method for correcting antenna phase errors. The method comprises:

[0007] Obtain positioning signals of the same terminal at different locations, and obtain the channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0008] Obtain the estimated value of the delay power spectrum of each channel according to the channel frequency domain response matrix;

[0009] Determining a direct path component in a time delay power spectrum estimate;

[0010] The antenna phase error is obtained according to the direct path component, and the antenna phase error is corrected according to the antenna phase error.

[0011] In one embodiment, obtaining a delay power spectrum estimate of each channel according to a channel frequency domain response matrix includes:

[0012] Extracting the channel frequency domain response vector of each channel in the channel frequency domain response matrix;

[0013] Based on the channel frequency domain response vector of each channel, the delay power spectrum estimation value of each channel is obtained through an iterative adaptive direction estimation algorithm.

[0014] In one embodiment, determining the direct path component in the delay power spectrum estimate includes:

[0015] The spectrum peak component is extracted from the time delay power spectrum estimation value, and the direct path component is identified in the spectrum peak component.

[0016] In one embodiment, obtaining an antenna phase error according to a direct path component, and correcting the antenna phase error according to the antenna phase error include:

[0017] The phase of the direct path component is obtained according to the direct path component, and the phase error between antenna array elements is obtained according to the phase of the direct path component;

[0018] An antenna phase error function is obtained according to the phase error between antenna array elements, and antenna phase error correction is implemented according to the antenna phase error function.

[0019] In one embodiment, after obtaining the direct path component phase according to the direct path component and obtaining the phase error between antenna array elements according to the direct path component phase, the method further includes:

[0020] According to the antenna array structure, the phase difference caused by the path difference between antenna array elements is compensated to obtain an updated phase error between antenna array elements.

[0021] In one embodiment, the method further comprises:

[0022] Acquire positioning signals of the same terminal at different locations multiple times, and obtain multiple updated phase errors between antenna elements based on the positioning signals;

[0023] An average value of the updated phase errors between antenna array elements is obtained, and an antenna phase error function is obtained according to the average value of the updated phase errors between antenna array elements.

[0024] In one embodiment, obtaining positioning signals of the same terminal at different locations and obtaining a channel frequency domain response matrix of a wireless channel based on the positioning signals includes:

[0025] Acquire the positioning signal, perform time-frequency conversion on the positioning signal, and obtain a frequency domain signal of the positioning signal;

[0026] Perform channel estimation on the frequency domain signal according to the positioning signal to obtain the frequency domain response matrix of the wireless channel;

[0027] The radio frequency channel error in the frequency domain response matrix is corrected according to the radio frequency channel correction coefficient to obtain a corrected channel frequency domain response matrix.

[0028] In a second aspect, the present application further provides an antenna phase error correction device. The device comprises:

[0029] an acquisition unit, configured to acquire positioning signals of the same terminal at different locations, and acquire a channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0030] A calculation unit, configured to obtain a delay power spectrum estimation value of each channel according to a channel frequency domain response matrix;

[0031] A determination unit, configured to determine a direct path component in a delay power spectrum estimation value;

[0032] The correction unit is used to obtain the antenna phase error according to the direct path component and implement antenna phase error correction according to the antenna phase error.

[0033] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the following steps are performed:

[0034] Obtain positioning signals of the same terminal at different locations, and obtain the channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0035] Obtain the estimated value of the delay power spectrum of each channel according to the channel frequency domain response matrix;

[0036] Determining a direct path component in a time delay power spectrum estimate;

[0037] The antenna phase error is obtained according to the direct path component, and the antenna phase error is corrected according to the antenna phase error.

[0038] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps:

[0039] Obtain positioning signals of the same terminal at different locations, and obtain the channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0040] Obtain the estimated value of the delay power spectrum of each channel according to the channel frequency domain response matrix;

[0041] Determining a direct path component in a time delay power spectrum estimate;

[0042] The antenna phase error is obtained according to the direct path component, and the antenna phase error is corrected according to the antenna phase error.

[0043] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the following steps:

[0044] Obtain positioning signals of the same terminal at different locations, and obtain the channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0045] Obtain the estimated value of the delay power spectrum of each channel according to the channel frequency domain response matrix;

[0046] Determining a direct path component in a time delay power spectrum estimate;

[0047] The antenna phase error is obtained according to the direct path component, and the antenna phase error is corrected according to the antenna phase error.

[0048] The above-mentioned antenna phase error correction method, device, base station, storage medium and computer program product, wherein a terminal with a known position sends a positioning signal to the base station at different terminal positions, and the base station obtains the positioning signal of the same terminal at different positions. The received positioning signal includes a mixed signal of all paths of the direct path and the reflected path, which is processed, and the frequency domain response matrix of the wireless channel is obtained according to the positioning signal; the delay power spectrum estimate value of each channel is calculated according to the frequency domain response matrix, and the direct path component in the delay power spectrum estimate value is extracted, and then the phase is calculated based on the direct path component, and then the antenna phase error estimate value is obtained according to the phase difference between antenna array elements, and the antenna phase error correction is implemented according to the antenna phase error estimate value.

[0049] This method uses actual positioning signals to estimate the antenna phase error curve in a complex multipath environment. By obtaining an accurate direct path component from the positioning signal, an accurate estimation of the antenna phase error function is achieved based on the direct path component without adding additional facilities. Compared with the traditional method of measuring the phase error curve in an active experiment in a microwave anechoic chamber, this method uses actual positioning signals to estimate the antenna phase error, can be applied in multipath environments, greatly reduces the computational cost, and compared with the self-correction method, this method has low computational complexity and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A diagram illustrating an application environment of an antenna phase error correction method according to an embodiment;

[0051] Figure 2 is a flow chart of a method for correcting antenna phase errors in one embodiment;

[0052] Figure 3 A schematic diagram of a positioning system configuration in one embodiment;

[0053] Figure 4 is a flow chart of a method for correcting antenna phase errors in another embodiment;

[0054] Figure 5 A flow chart of a method for calculating a frequency domain response matrix in one embodiment;

[0055] Figure 6A flow chart of generating an antenna phase error function in one embodiment;

[0056] Figure 7 FIG. 1 is a diagram of an experimental configuration for antenna phase error correction in one embodiment;

[0057] Figure 8 A diagram comparing an estimated value of an antenna phase error function and an estimated value of collected data in one embodiment;

[0058] Figure 9 FIG1 is a diagram of an experimental configuration for antenna phase error correction and AoA estimation in another embodiment;

[0059] Figure 10 Graph showing the empirical cumulative distribution function of AoA estimation error in one embodiment;

[0060] Figure 11 is a structural block diagram of an antenna phase error correction device in one embodiment;

[0061] Figure 12 FIG. 4 is a diagram showing the internal structure of a base station in an embodiment. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0063] The antenna phase error correction method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, terminal 102 communicates with base station 104. Base station 104 obtains positioning signals from the same terminal at different locations and obtains a frequency domain response matrix of the wireless channel based on the positioning signals. Base station 104 obtains a delay power spectrum estimate for each channel based on the channel frequency domain response matrix. Base station 104 determines the direct path component in the delay power spectrum estimate. Base station 104 obtains an antenna phase error based on the direct path component and performs antenna phase error correction based on the antenna phase error.

[0064] Terminal 102 may be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices may include smart speakers, smart TVs, smart air conditioners, and smart car devices. Portable wearable devices may include smart watches, smart bracelets, and head-mounted devices. Base station 104 may be a macro base station, a micro base station, a remote radio frequency (RFR), a repeater, or an indoor distribution system.

[0065] In one embodiment, Figure 2 As shown, a method for correcting antenna phase errors is provided, which is applied to Figure 1 Taking the base station 104 in FIG. 1 as an example, the method includes the following steps:

[0066] Step 202: Acquire positioning signals of the same terminal at different locations, and acquire a channel frequency domain response matrix of the wireless channel based on the positioning signals.

[0067] The positioning system consists of a terminal and a base station. The base station is equipped with an antenna array, and the terminal is located within the base station's antenna coverage area. The terminal transmits positioning signals to the base station at different locations. The base station calibrates the terminal's position at each location where the positioning signal is transmitted. The base station uses the positioning signals received by the antenna array to estimate the antenna phase error. The base station can calibrate the terminal's position using high-precision position measurement methods such as total stations, lidar, or differential global navigation satellite system signals.

[0068] When calibrating the terminal's position, the base station processes the positioning signal to obtain a channel frequency domain response matrix, and extracts positioning parameters such as AoA (Angle of Arrival) or ToA (Time of Arrival) based on the frequency domain response matrix extracted from the positioning signal. Based on the traditional method, this embodiment further calculates the channel frequency domain response matrix to correct the antenna phase error, reusing the software and hardware facilities in the positioning system. There is no need to design dedicated correction signals and additional dedicated hardware, thereby reducing costs and increasing practicality.

[0069] Step 204: Obtain a delay power spectrum estimation value of each channel according to the channel frequency domain response matrix.

[0070] The acquired frequency domain response matrix signal includes, in addition to the terminal's transmitted positioning signal, signals generated by reflections from walls, pillars, pipes, and metal equipment due to multipath effects. Multipath signals can be represented using the delay power spectrum. The delay power spectrum, also known as the delay spectrum, indicates the power level over the delay.

[0071] This embodiment calculates the delay power spectrum of the channel frequency-domain response matrix, derives the direct path component of the positioning signal based on the calculated delay power spectrum, and then derives the phase based on the direct path data. This embodiment can correct antenna phase errors in multipath environments with low computational complexity and strong practicality.

[0072] Step 206: Determine the direct path component in the delay power spectrum estimate.

[0073] The delay power spectrum includes delay information for all paths. Extracting the direct path component from the delay power spectrum facilitates subsequent antenna phase error correction based on the direct path data. Determining the direct path component from the delay power spectrum can be achieved by combining detection algorithms and identification methods.

[0074] Step 208: Obtain an antenna phase error according to the direct path component, and perform antenna phase error correction according to the antenna phase error.

[0075] The direct path component can be used to extract the direct path phase. Based on this phase, the phase error between antenna elements can be calculated, thereby correcting the antenna phase error. For example, the obtained antenna phase error can be used to estimate an antenna phase error function, which can then be used to correct the antenna phase error.

[0076] The above-mentioned antenna phase error correction method obtains positioning signals from the same terminal at different locations, obtains the frequency domain response matrix of the wireless channel based on the positioning signals, and then determines the direct path component in the delay power spectrum from the frequency domain response matrix. The antenna phase error is then calculated based on this direct path component, and the antenna phase error is then corrected based on the antenna phase error. Based on the positioning system, this method can calculate antenna phase error in field environments with complex multipath, avoiding the need for precise measurement of antenna phase error in a microwave anechoic chamber. This significantly reduces the cost of antenna phase error correction and improves the practicality of AoA technology in wireless positioning systems.

[0077] In one embodiment, a delay power spectrum estimation value of each channel is obtained according to a channel frequency domain response matrix, including: extracting a channel frequency domain response vector of each channel in the channel frequency domain response matrix; and obtaining a delay power spectrum estimation value of each channel through an iterative adaptive azimuth estimation algorithm based on the channel frequency domain response vector of each channel.

[0078] For example, based on the channel frequency domain response matrix, the delay power spectrum of the channel can be represented by the channel frequency domain response vector and the delay matching vector of each channel. By solving the function, an estimated value of the delay power spectrum is obtained. For example, an estimated value of the delay power spectrum can be obtained using the IAA-APES (Iterative Adaptive Approach-based Amplitude and Phase Estimation) algorithm. Using IAA-APES, a weighted least squares problem can be solved iteratively to obtain an estimated value of the delay power spectrum.

[0079] In one embodiment, determining the direct path component in the delay power spectrum estimation value includes: extracting spectrum peak components from the delay power spectrum estimation value, and identifying the direct path component in the spectrum peak components.

[0080] For example, when extracting the direct path component from the acquired delay power spectrum, a detection algorithm, such as peak point detection, constant false alarm rate detection, etc., can be first used to extract several significant spectrum peak components from the delay power spectrum; then, according to certain identification criteria, such as the shortest propagation path criterion, the maximum power criterion, etc., the direct path component can be identified from the acquired spectrum peak components.

[0081] In one embodiment, an antenna phase error is obtained based on a direct path component, and antenna phase error correction is implemented based on the antenna phase error, including: obtaining a direct path component phase based on the direct path component, obtaining an inter-antenna array element phase error based on the direct path component phase; obtaining an antenna phase error function based on the inter-antenna array element phase error, and implementing antenna phase error correction based on the antenna phase error function.

[0082] After obtaining the direct path component, the phase of the direct path component can be obtained by extracting the argument of the complex number of the direct path component. The phase difference of the antenna array is calculated based on the obtained direct path phase, and the antenna phase error estimate is obtained based on the phase difference between multiple antenna elements. The phase error function is determined based on the estimated phase difference between antenna elements, and the antenna phase error is corrected based on the phase error function.

[0083] In one embodiment, after obtaining the phase error between antenna elements according to the phase of the direct path component, the method further includes: compensating for the phase difference caused by the path difference between antenna array elements according to the antenna array structure to obtain an updated phase error between antenna elements.

[0084] Since the phase of the direct path includes not only the phase error of the array antenna, but also the phase difference caused by the different path lengths of the positioning signal reaching each array element when it propagates in free space, this phase difference is related to the formation of the antenna array.

[0085] Exemplarily, according to the antenna array structure, for example, in a ULA (Uniform Linear Array), the phase difference caused by the path difference between the array elements is determined according to the angle between the incident positioning signal and the array normal direction, and the phase difference caused by the path difference between the antenna array elements is compensated to obtain an updated phase error between the antenna array elements.

[0086] In one embodiment, the method further includes: obtaining positioning signals of the same terminal at different locations multiple times, and obtaining multiple updated phase errors between antenna elements based on the positioning signals; obtaining an average value of the updated phase errors between antenna elements, and obtaining an antenna phase error function based on the average value of the updated phase errors between antenna elements.

[0087] To reduce estimation errors, the terminal can transmit positioning signals multiple times at different locations. The base station then obtains multiple wireless channel frequency response matrices and uses these repeated channel response data to calculate the antenna phase error estimate. The phase difference calculated over multiple times can be replaced by the average of these multiple estimated phase differences, thereby reducing the impact of noise. Alternatively, a median filter can be used to remove outliers from the sequence, and then the average of the median-filtered data sequence is taken as the phase difference estimate from the multiple repeated measurements.

[0088] The phase error function of each element of the antenna array is calculated based on the phase difference estimate, thereby obtaining the phase error function of the entire antenna array. The antenna phase error in the positioning system is corrected based on the calculated phase error function.

[0089] When calculating the phase error function, a median filter can be used to remove outliers in the data first, and then methods such as cubic spline interpolation, polynomial fitting or local regression algorithm can be used to estimate the phase error function.

[0090] In one embodiment, positioning signals of the same terminal at different locations are obtained, and a channel frequency domain response matrix of a wireless channel is obtained based on the positioning signals, including: obtaining the positioning signal, performing time-frequency conversion on the positioning signal, and obtaining a frequency domain signal of the positioning signal; performing channel estimation on the frequency domain signal based on the positioning signal, and obtaining a frequency domain response matrix of the wireless channel; and correcting the radio frequency channel error in the frequency domain response matrix based on the radio frequency channel correction coefficient, and obtaining a corrected channel frequency domain response matrix.

[0091] The channel frequency domain response matrix of the positioning signal is obtained by performing signal processing on the positioning signal. Exemplarily, when obtaining the channel frequency domain response matrix of the positioning signal, the received positioning signal is first subjected to data processing such as filtering to obtain a positioning signal sequence, and then the frequency domain signal of the positioning signal is obtained by methods such as Fourier transform; then, channel estimation is performed on the frequency domain signal based on the positioning signal to obtain the frequency domain response matrix of the wireless channel between the terminal and the base station; for the calculated frequency domain response matrix, the RF channel error in the frequency domain response matrix is corrected by the RF channel correction coefficient, and this embodiment calculates the antenna phase error function based on the corrected frequency domain response matrix. Wherein, when performing channel estimation, a least squares (LS) channel estimator can be used to calculate the wireless channel frequency domain response matrix.

[0092] Figure 3 The following is a schematic diagram of the positioning system configuration: Figure 3 The positioning system shown includes a base station and a mobile terminal. The mobile terminal transmits positioning signals at different locations within the coverage area of the base station antenna array. The positioning system accurately calibrates the position of the terminal at each location where the positioning signal is transmitted. The calibration method can be a high-precision position measurement method such as a total station, lidar or differential global navigation satellite system signal.

[0093] like Figure 3 As shown, in one embodiment, the base station estimates the phase error using the multi-channel positioning signal received by the antenna array. The antenna phase error correction method is as shown in FIG. Figure 4 As shown, the following steps are included:

[0094] Step 410: Receive positioning signals of the same terminal at different locations, and obtain a channel frequency domain response matrix of the wireless channel according to the positioning signals.

[0095] Step 420: Obtain an antenna phase error function according to the channel frequency domain response matrix, and perform antenna phase error correction using the antenna phase error function.

[0096] Among them, Figure 5 As shown, in step 410, receiving positioning signals of the same terminal at different locations, and obtaining a channel frequency domain response matrix of a wireless channel according to the positioning signals includes the following steps:

[0097] Step 502: Receive a set of positioning signals sent by the same terminal at different locations.

[0098] In order to better measure the phase error within the coverage of the base station antenna array, the terminal's position covers the antenna array coverage, and the measurement positions do not require equal angular spacing.

[0099] Assuming that the number of antenna elements in the base station receiving antenna array is N, the angle set measured by the antenna array is expressed as {θ k} k＝1,…,K At each measurement angle, the base station equipped with array antennas will receive multi-channel positioning reference signals. k The received positioning signal is recorded as function y k (t): Among them, the collection represents the real number space, represents the complex space, Represents the N×1 dimensional complex space. The set of positioning signals received at all measurement angles is represented as {y k (t)} k＝1,…,KThe method of this embodiment implements the estimation of antenna phase error based on the received positioning signal set.

[0100] In one embodiment, considering the continuity of the phase error curve, the angular spacing of the terminal positioning signals is measured in a range of 3 degrees to 8 degrees.

[0101] Step 504: Process the acquired positioning signal set to obtain a positioning signal sequence.

[0102] For the positioning signal y received in the positioning signal set k (t) Perform RF and IF signal processing, including signal filtering, down-conversion, extraction, and other processing methods, and perform ADC (Analog-Digital Convert) to obtain the baseband receiving positioning signal sequence y k [m] This embodiment does not limit the method and steps for processing the positioning signal, and a corresponding processing module may be provided in the receiver of the positioning system base station.

[0103] Step 506: Perform time-frequency conversion on the positioning signal sequence to obtain a frequency domain received positioning signal matrix.

[0104] Baseband receiving positioning signal sequence y k [m] performs a time-frequency transform to obtain a frequency domain received positioning signal matrix. Exemplarily, the time-frequency transform can be completed by FFT (Fast Fourier Transform).

[0105] For broadband positioning systems, the positioning signal transmitted by the terminal is a broadband positioning signal occupying a certain bandwidth. If the positioning signal bandwidth is set to B, the bandwidth B occupied by the frequency domain signal can be divided into M sub-bands. When the time-frequency transform is realized by FFT, M is the number of FFT points, and the frequency domain received data can be arranged into an M×N dimensional matrix, which is expressed as In the M×N matrix of the frequency domain received positioning signal, the nth column represents the M-dimensional frequency domain data vector received by the nth receiving channel.

[0106] Step 508: Perform channel estimation based on the frequency domain received positioning signal matrix and the transmitted positioning signal sequence to obtain a channel frequency domain response matrix.

[0107] Channel estimation is performed based on the frequency domain received positioning signal matrix and the transmitted positioning signal sequence to estimate the frequency domain response CFR (Channel Frequency Response) of the wireless channel between the terminal and the base station. The frequency domain received positioning signal matrix is Y k , the transmitted positioning signal sequence is expressed as The obtained wireless channel frequency domain response matrix is expressed as

[0108] This embodiment has no limitation on the channel estimation method and steps. Exemplarily, a least squares channel estimator may be used to calculate the frequency domain response matrix of the wireless channel. Represents the element in the mth row and nth column of the frequency domain response matrix of the wireless channel, and the expression is:

[0109]

[0110] In formula (1), [Y k ] (m,n) Represents the frequency domain received positioning signal matrix Y k The element in row m and column n; x m is the transmitted positioning signal sequence in the mth subband, that is, the mth element of the transmitted positioning signal sequence vector x.

[0111] Step 510: Correct the channel frequency domain response matrix using the radio frequency channel correction coefficient measurement value to obtain a corrected frequency domain response matrix.

[0112] The radio frequency channel error in the estimated channel frequency domain response matrix is corrected using the measured radio frequency channel correction coefficient.

[0113] For example, in this positioning system, a base station as a receiving device measures the frequency response of each radio frequency channel of the base station within the working bandwidth B, and the radio frequency channel frequency response of M sub-bands and N receiving channels is recorded as This matrix is also the radio frequency channel correction coefficient of the base station serving as a receiving device.

[0114] The correction process of the wireless channel frequency domain response matrix is:

[0115]

[0116] In formula (2), The operator means dividing the corresponding elements of the two matrices to obtain a matrix of the same dimension. Through the correction of the RF channel correction coefficient, the corrected wireless channel frequency domain response matrix is obtained, which is expressed as

[0117] Next, step 420 is performed according to the channel frequency domain response matrix H k An antenna phase error function is obtained, and antenna phase error correction is further explained using the antenna phase error function.

[0118] For an N-element antenna array, each element corresponds to an antenna phase error function, expressed as Where Θ represents the angular coverage interval of the array. The antenna phase error function is expressed as a vector function, which is expressed as The input parameter of the antenna phase error function is the incident angle θ, and the output is the phase error of N array elements at the current angle.

[0119] For example, when the incident angle is When , the output of the antenna phase error function is in(·) T Represents the vector or matrix transpose operator.

[0120] Because in the actual positioning environment, walls, pillars, water pipes and metal equipment will cause signal reflection, so the wireless channel frequency domain response matrix H collected each time is k There is not only k The signal components propagating to the array in the direction of the channel and the coherent signal components incident from other directions due to multipath propagation need to be calculated in the channel frequency domain response matrix H. k The accurate estimation of the direct path component phase is achieved, and then the accurate estimation of the antenna phase error function is achieved.

[0121] like Figure 6 As shown, step 420 includes the following steps:

[0122] Step 602: Obtain a delay power spectrum estimation value of each channel according to the channel frequency domain response matrix.

[0123] Based on the wireless channel frequency domain response matrix H k , the frequency domain response of the wireless channel of the nth channel is recorded as [H k ] :,n , which is the wireless channel frequency domain response matrix H k At the same time, it is assumed that the delay range that the base station can cover is [0,τ max ]; where τ max Determined by the maximum range of the base station, assuming that the delay range is divided into P equal parts with δτ as the interval, the delay grid point set of the delay power spectrum is expressed as {τ p} p＝1,…,P .

[0124] The frequency domain response vectors of each channel wireless channel on the delay grid point set are unified in the delay power spectrum matrix , wherein the nth column represents the delay power spectrum obtained based on the nth receiving channel data.

[0125] The delay matching vector on the delay grid point set is denoted as {a p} p＝1,…,P .

[0126] According to the above settings, the IAA-APES spectrum estimator is used to extract the channel frequency domain response vector [H k] :,n The corresponding time delay power spectrum is estimated respectively [Ξ k ] :,n , IAA-APES uses an iterative approach to solve the following weighted least squares problem to obtain an estimate of the delay spectrum:

[0127]

[0128] In formula (3), represents the weighted l2 norm of the solution vector, is a weighting matrix, which indicates that for the nth receiving channel, the delay is τ p The interference covariance matrix at time .

[0129] Step 604: Determine the direct path component in the delay power spectrum estimate.

[0130] According to the estimated value of the time delay power spectrum of each channel [Ξ k ] :,n ,n=1,…,N, determine the direct path component.

[0131] First, a detection algorithm, such as peak point detection, constant false alarm rate detection, etc., is used to estimate the delay power spectrum [Ξ k ] :,n A number of significant spectrum peak components are extracted; and then the direct path component is identified from the extracted spectrum peak components according to an identification criterion, such as the shortest propagation path criterion, the maximum power criterion, etc.

[0132] For the time delay power spectrum of the nth channel [Ξ k ] :,n , if the p0th time delay grid point corresponds to the direct path component, then the direct path component is recorded as:

[0133] Step 606: Extract the phase of the direct path component.

[0134] According to the direct path component value ξ k,n Extract the corresponding angle as θ k The direct path of θ causes a phase rotation of 5 in the nth channel. For example, by extracting the complex number ξ k,n The phase of the direct path component is improved by the angle of

[0135] Take, expressed as:

[0136]

[0137] Step 608: Compensate for the phase difference caused by the path difference between antenna array elements according to the antenna array structure to obtain an updated phase error between antenna array elements.

[0138] Due to the phase It not only includes the phase error of the array antenna, but also includes the phase difference caused by the different path lengths of the signal reaching each element when it propagates in free space. This phase difference is related to the array formation. For example, for ULA, when the angle between the incident signal and the array normal direction is θ, if the first array element is used as the reference array element, for the nth array element, the phase compensation value for this path difference d is

[0139] The remaining phase after compensating for the phase difference caused by the path difference between array elements is denoted as φ k,n , then for ULA,

[0140] have:

[0141]

[0142] In formula (5), φ k,n Indicates that the nth antenna array element has an incident angle of θ k The phase error of the signal.

[0143] Step 610: Determine a phase error function using the updated estimated phase difference between antenna elements, and perform antenna phase error correction based on the phase error function.

[0144] For each element n, n=1,…,N of the antenna array, according to the angle set {θ k} k＝1,…,K The phase error φ estimated above k,n ,k=1,…,K Estimate the corresponding antenna phase error function

[0145] The antenna phase error value φ can be k,n ,k=1,…,K is regarded as the antenna phase error function

[0146] In θ is {θ k} k＝1,…,K The measured value of the function when , then for this function, polynomial fitting, neural network and other methods can be used to solve it, and we can get back, The corresponding conclusion can be drawn.

[0147] In one embodiment, to reduce the estimation error, for each angle, the terminal may transmit multiple positioning signals, and the base station may obtain multiple observation values of the wireless channel response. k If the terminal transmits L positioning signals, the base station obtains the estimated results of the wireless channel L times. For multiple positioning signal measurement values, the average value of multiple estimated phase difference values can be used instead to reduce the impact of noise.

[0148] Since the initial phase of the receiver may be different each time the positioning signal is received, in order to make the multiple estimated phases be used jointly for antenna phase error estimation, the first array element can be used as the reference array element when calculating the antenna phase error. And φ n (θ),n≠1 then according to Calculate, where the superscript l represents the antenna phase error estimate obtained based on the positioning signal transmitted for the lth time.

[0149] Antenna phase error function estimated based on the above field positioning data It can be used to compensate for antenna phase errors in actual positioning systems.

[0150] This embodiment proposes to use the IAA-APES algorithm to achieve super-resolution estimation of multipath components and direct path components, and at the same time achieve accurate estimation of the phase of the direct path component. After each receiving channel achieves accurate estimation of the phase of the direct path component, it can be used to achieve accurate estimation of the antenna phase error function.

[0151] When the positioning base station processes the positioning signal, the traditional positioning base station will extract the wireless channel frequency domain response matrix H k Extract positioning parameters such as AoA and ToA. Therefore, the antenna phase error correction method based on field data proposed in this embodiment reuses the software and hardware infrastructure in the positioning system to the greatest extent, without the need to design a dedicated correction signal or use additional dedicated hardware. All that is required is to collect the wireless channel frequency domain response matrix H each time. k When the current terminal position is accurately calibrated, the corresponding accurate θ k , the calculation method is simple, the calculation complexity is low, and the practicality is strong.

[0152] In one embodiment, a 5G pico base station indoor positioning system based on the sub-6GHz frequency band is used as an example to verify the effectiveness of the antenna phase error correction method. This embodiment uses 5G's SRS (Sounding Reference Signal) as the positioning signal. The bandwidth occupied by the positioning signal is 100MHz. The pico base station used is equipped with a four-element ULA, and the array normal direction is defined as zero degrees. The angle between the incident signal and the normal is positioned as θ, and the antenna array covers an angle range of -60 degrees to +60 degrees.

[0153] Figure 7 This is the experimental configuration diagram for collecting measured data for antenna phase error estimation, as shown in the figure. Figure 7As shown, positioning signals are collected at twenty-eight different terminal positions, and the collection is repeated one hundred times at each terminal position.

[0154] This embodiment estimates and calculates the phase error function of each element in the antenna array through data from one hundred repeated measurements. As mentioned above, in order to solve the problem of different initial phases of the receiver each time, the first element is used as the reference element. The phase error at discrete angles estimated based on the collected positioning signal and the result of the phase error function estimation are as follows: Figure 8 shown. Figure 8 The phase error estimates of the second to fourth antenna elements are the average values of one hundred measurements. In the estimation results of the antenna phase error function, as well as They are all obtained by fitting a polynomial of order based on the phase error estimates at these discrete angles.

[0155] In one embodiment, Figure 9 The figure shows an experimental configuration diagram for collecting measured data for antenna phase error compensation and AoA estimation in another embodiment. Based on the above antenna error phase correction method, Figure 9 The fifty-six terminal positions shown in the figure are also repeatedly collected one hundred times for positioning data. For the collected positioning data, the antenna phase error is compensated for without antenna phase compensation and according to the antenna error phase correction method disclosed in the above embodiment. The empirical cumulative distribution function results of the overall AoA estimation error at the fifty-six positions are as follows: Figure 10 As shown, after the antenna phase error is compensated for by the antenna phase error estimation function obtained by the antenna phase correction method according to the above embodiment, the AOA estimation accuracy is significantly improved, and the 90% AoA estimation error is reduced from 4.1 degrees to about 2.8 degrees.

[0156] This embodiment estimates and compensates for the antenna phase error based on the multipath signal in the actual positioning system without adding additional facilities. Compared with the phase error curve measurement method of active experiments in a microwave darkroom, this embodiment has good practicality and low computational complexity, significantly reduces the cost of correcting the antenna error phase, and has high accuracy, thereby improving the practicality of the AoA technology of the wireless positioning system.

[0157] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0158] Based on the same inventive concept, embodiments of the present application also provide an antenna phase error correction device for implementing the antenna phase error correction method described above. The solution provided by this device is similar to the solution described in the method described above. Therefore, the specific limitations of one or more embodiments of the antenna phase error correction device provided below can be found in the limitations of the antenna phase error correction method described above and will not be further elaborated here.

[0159] In one embodiment, Figure 11 As shown, an antenna phase error correction device is provided, including: an acquisition unit 1102, a calculation unit 1104, a determination unit 1106 and a correction unit 1108, wherein:

[0160] An acquiring unit 1102 is configured to acquire positioning signals of the same terminal at different locations, and acquire a channel frequency domain response matrix of the wireless channel based on the positioning signals;

[0161] A calculation unit 1104 is configured to obtain a delay power spectrum estimation value of each channel according to the channel frequency domain response matrix;

[0162] A determining unit 1106, configured to determine a direct path component in a delay power spectrum estimate;

[0163] The correction unit 1108 is configured to obtain an antenna phase error according to the direct path component, and perform antenna phase error correction according to the antenna phase error.

[0164] In one embodiment, the calculation unit 1104 is further used to extract the channel frequency domain response vector of each channel in the channel frequency domain response matrix; based on the channel frequency domain response vector of each channel, the delay power spectrum estimation value of each channel is obtained by an iterative adaptive azimuth estimation algorithm.

[0165] In one embodiment, the determining unit 1106 is further configured to extract a spectrum peak component from the delay power spectrum estimation value, and identify a direct path component from the spectrum peak component.

[0166] In one embodiment, the correction unit 1108 is further used to obtain the phase of the direct path component based on the direct path component, obtain the phase error between antenna elements based on the phase of the direct path component; obtain the antenna phase error function based on the phase error between antenna elements, and implement antenna phase error correction based on the antenna phase error function.

[0167] In one embodiment, the correction unit 1108 is further configured to compensate for the phase difference caused by the path difference between antenna array elements according to the antenna array structure, and obtain an updated phase error between antenna array elements.

[0168] In one embodiment, the correction unit 1108 is further used to obtain positioning signals of the same terminal at different locations multiple times, and obtain multiple updated phase errors between antenna elements based on the positioning signals; obtain the average value of the updated phase errors between antenna elements, and obtain the antenna phase error function based on the average value of the updated phase errors between antenna elements.

[0169] In one embodiment, the acquisition unit 1102 is also used to acquire the positioning signal, perform time-frequency conversion on the positioning signal, and obtain the frequency domain signal of the positioning signal; perform channel estimation on the frequency domain signal based on the positioning signal to obtain the frequency domain response matrix of the wireless channel; and correct the RF channel error in the frequency domain response matrix based on the RF channel correction coefficient to obtain the corrected channel frequency domain response matrix.

[0170] Each module in the antenna phase error correction device described above may be implemented in whole or in part via software, hardware, or a combination thereof. Each module may be embedded in or independent of the processor in base station 104 in hardware form, or may be stored in a memory in base station 104 in software form, so that the processor can call and execute the corresponding operations of each module.

[0171] In one embodiment, a base station 104 is provided. The base station 104 is provided in a positioning system and is equipped with an antenna array for communicating with the outside world. The internal structure of the base station can be shown as follows: Figure 12 As shown. The base station includes a processor, memory, a communication interface, a display screen, and an input device connected via a system bus. The base station's processor provides computing and control capabilities. The base station's memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and computer program in the non-volatile storage medium. When executed by the processor, the computer program implements an antenna phase error correction method.

[0172] Those skilled in the art will understand that Figure 12The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0173] In one embodiment, a base station is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0174] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0175] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0176] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0177] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0178] Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0179] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0180] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0181] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for correcting antenna phase errors, characterized in that: The method comprises: Obtaining positioning signals of the same terminal at different locations, and obtaining a channel frequency domain response matrix of the wireless channel based on the positioning signals; Obtaining a time delay power spectrum estimation value of each channel according to the channel frequency domain response matrix; Determining a direct path component in the delay power spectrum estimate; An antenna phase error is obtained according to the direct path component, and antenna phase error correction is performed according to the antenna phase error.

2. The method according to claim 1, characterized in that Obtaining a delay power spectrum estimation value of each channel according to the channel frequency domain response matrix includes: Extracting a channel frequency domain response vector for each channel in the channel frequency domain response matrix; Based on the channel frequency domain response vector of each channel, a time delay power spectrum estimation value of each channel is obtained by an iterative adaptive direction estimation algorithm.

3. The method according to claim 1, characterized in that The determining of the direct path component in the delay power spectrum estimate includes: A spectrum peak component is extracted from the time-delay power spectrum estimation value, and the direct path component is identified in the spectrum peak component.

4. The method according to claim 1, wherein Obtaining an antenna phase error according to the direct path component, and correcting the antenna phase error according to the antenna phase error, includes: Obtaining a direct path component phase according to the direct path component, and obtaining an inter-antenna array element phase error according to the direct path component phase; An antenna phase error function is obtained according to the phase error between the antenna array elements, and antenna phase error correction is implemented according to the antenna phase error function.

5. The method according to claim 4, characterized in that After obtaining the direct path component phase according to the direct path component and obtaining the phase error between antenna array elements according to the direct path component phase, the method further includes: According to the antenna array structure, the phase difference caused by the path difference between antenna array elements is compensated to obtain an updated phase error between antenna array elements.

6. The method according to claim 5, characterized in that The method further comprises: Acquire positioning signals of the same terminal at different locations multiple times, and obtain a plurality of updated inter-antenna element phase errors according to the positioning signals; An average value of the updated phase errors between antenna array elements is obtained, and an antenna phase error function is obtained according to the updated average value of the phase errors between antenna array elements.

7. The method according to any one of claims 1 to 6, characterized in that The obtaining of positioning signals of the same terminal at different locations, and obtaining a channel frequency domain response matrix of a wireless channel according to the positioning signals, includes: Acquire the positioning signal, perform time-frequency conversion on the positioning signal, and obtain a frequency domain signal of the positioning signal; performing channel estimation on the frequency domain signal according to the positioning signal to obtain a frequency domain response matrix of the wireless channel; The radio frequency channel error in the frequency domain response matrix is corrected according to the radio frequency channel correction coefficient to obtain the corrected channel frequency domain response matrix.

8. An antenna phase error correction device, characterized in that: The device comprises: an acquiring unit, configured to acquire positioning signals of the same terminal at different locations, and acquire a channel frequency domain response matrix of the wireless channel based on the positioning signals; A calculation unit, configured to obtain a delay power spectrum estimation value of each channel according to the channel frequency domain response matrix; a determining unit, configured to determine a direct path component in the delay power spectrum estimate; A correction unit is used to obtain an antenna phase error according to the direct path component, and to perform antenna phase error correction according to the antenna phase error.

9. A base station comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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