Mixed modulus time domain cross-correlation direction of arrival estimation system and method
By calculating and accumulating the cross-correlation and delay cross-correlation results of RF component signals in a single-array dual RF hybrid analog-digital array, the problems of low utilization rate and low signal-to-noise ratio in the prior art are solved, and efficient and accurate wave arrival direction estimation is achieved.
Patent Information
- Application Number
- CN202510249827.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2025-06-24
AI Technical Summary
In the prior art, the low utilization rate of antenna arrays leads to high design costs, low computing efficiency, and it is difficult to accurately estimate the wave arrival direction in a low signal-to-noise ratio environment.
A single-array dual RF hybrid analog-digital array is used to calculate the cross-correlation and delay cross-correlation results between radio frequency component signals, accumulate to improve the signal-to-noise ratio, and extract the phase of the accumulated results to estimate the wave reach direction of the signal.
It improves the accuracy and efficiency of wave direction estimation, reduces design cost and computational complexity, and avoids complex symbol correction algorithms and phase blur.
Smart Images
Figure CN120195616A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical fields of wireless communication and radar signal processing, and particularly relates to a hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation system and method. Background Art
[0002] In driverless vehicles, the DOA (Direction of Arrival) of on-vehicle radars can be used to determine the orientations of surrounding vehicles, and thus predictions can be made in advance. In the large-scale millimeter-wave MIMO (Multiple-Input Multiple-Output) system of the fifth-generation mobile communication, DOA (Direction of Arrival) estimation support is also required to ensure the continuous stability of communication signals. The main research task of DOA (Direction of Arrival) estimation is how to efficiently and quickly estimate the direction of arrival of communication signals, so that the DOA (Direction of Arrival) method has real-time estimation ability and anti-noise ability in a large-array environment.
[0003] The existing DOA (Direction of Arrival) estimation methods based on hybrid analog-digital can be roughly divided into three categories: The first category is the DOA (Direction of Arrival) estimation method based on covariance matrix reconstruction. The idea is to use digital-domain algorithms such as classical spatial spectrum estimation to be extended to hybrid analog-digital, and MUSIC (Multiple Signal Classification) or ESPRIT (Estimation of Signal Parameters by Rotational Invariance Techniques) is generally used, and then extended to a partially connected phase shifter hybrid array.
[0004] The second category is the DOA (Direction of Arrival) estimation method combined with neural networks. The main idea is to use specific network models such as CNN (Convolutional Neural Network) and RNN (Recurrent Neural Network) to preprocess the received signals of traditional hybrid analog-digital arrays. The network model used is trained with simulated DOA (Direction of Arrival) data as the training set. After training, DOA (Direction of Arrival) estimation is performed.
[0005] The third category is to perform cross-correlation on the received signals of adjacent sub-arrays, accumulate the cross-correlation results after symbol correction, and extract DOA (Direction of Arrival) information. This type of algorithm has more advantages in practical applications than the previous ones, but there are also many disadvantages to be solved.
[0006] The first type of DOA (Direction of Arrival) estimation method compensates for the lack of spatial degrees of freedom caused by limited radio frequency (RF) components by increasing the training time, and has high computational complexity and long training time. At low signal-to-noise ratios, it is difficult to accurately obtain the noise subspace of this type of algorithm. The second type of method has special requirements for the training set due to the limitations of the network model, and also has problems such as too long training time and overfitting. In the third type of solution, first, due to phase ambiguity, N (the number of antennas in the sub-array) DOA (Direction of Arrival) estimation values will be obtained. To eliminate the ambiguity, N groups of code elements are used to test each possible DOA (Direction of Arrival) estimation or more complex operations are used to eliminate the ambiguity. Secondly, the sign of the amplitude cross-correlation result cannot be determined. If a special symbol correction scheme is adopted, the complexity of the algorithm will be greatly increased.
[0007] The above three types of methods have very low utilization rates of antenna arrays and require multiple sub-arrays. An array often only performs one operation, greatly increasing the design cost. The noise also undergoes multiple operations, and the operation results make the way the noise exists more complex and difficult to separate. Summary of the Invention
[0008] The object of the present invention is to provide a hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation system and method to solve the technical problems in the prior art such as low utilization rate of antenna arrays resulting in high design costs and low computational efficiency, and improve the accuracy of direction-of-arrival estimation.
[0009] To achieve the above object, the present invention is implemented by the following technical solutions: In a first aspect, the present invention discloses a mixed-modulus time-domain cross-correlation direction-of-arrival estimation system, including: A single-array dual-radio-frequency mixed-modulus array for receiving signals and sending the received signals to a radio-frequency component; The radio-frequency component is used to receive the signals from the single-array dual-radio-frequency mixed-modulus array, convert and modulate the received signals to obtain radio-frequency component signals, and transmit the radio-frequency component signals to a calculation module; wherein, the radio-frequency component includes a first radio-frequency component and a second radio-frequency component; the first radio-frequency component converts and modulates to obtain a first radio-frequency component signal; the second radio-frequency component converts and modulates to obtain a second radio-frequency component signal; The calculation module is used to calculate the first cross-correlation and the first delayed cross-correlation between the first radio-frequency component signals, calculate the second cross-correlation and the second delayed cross-correlation between the second radio-frequency component signals, calculate the third cross-correlation between the first radio-frequency component signals and the second radio-frequency component signals, accumulate the first cross-correlation, the first delayed cross-correlation, the second cross-correlation, the second delayed cross-correlation and the third cross-correlation to obtain an accumulated result; extract the phase of the accumulated result, and estimate the direction of arrival of the signal according to the phase of the accumulated result.
[0010] Preferably, the single-array dual-radio-frequency mixed-modulus array includes antenna elements, these antenna elements form a single array; the first radio-frequency component is connected to the first antenna elements, and the second radio-frequency component is connected to all antenna elements.
[0011] Preferably, the antenna elements in the single array are further connected to an analog beamformer, and the analog beamformer is used to form an analog beam according to the values of the two parameters of the number of antenna elements and the time-domain symbol; The analog beamformer is expressed as:
[0012] In the formula, represents the analog beamformer connected to the th antenna element; represents the analog beam of the th time-domain symbol; is the index of the time-domain symbol; is the index of the antenna element; is the number of antenna elements.
[0013] Preferably, the first cross-correlation, the second cross-correlation, and the third cross-correlation are calculated using the following formula:
[0014]
[0015]
[0016] In the formula, denotes the cross-correlation between the RF component signals and the RF component signals; denotes the RF component signal; denotes the RF component signal; the superscript * represents the complex conjugate; is the additive white Gaussian noise; is the sum of the cross-correlations between the additive white Gaussian noise and the received signal; denotes the narrowband line-of-sight propagation path signal; denotes the cross-correlation between the radiation patterns of different RF component signals; is the radiation pattern of the RF component signal; is the radiation pattern of the RF component signal; is the Doppler frequency; is the index of the time-domain symbol, denotes the direction of arrival in the beam domain.
[0017] Preferably, the first delay cross-correlation and the second delay cross-correlation are calculated using the following formula:
[0018] In the formula, denotes the first delay cross-correlation; denotes the first RF component signal; denotes the first RF component delay signal; the superscript * represents the complex conjugate; is the first RF component delay cross-correlation noise; denotes the narrowband line-of-sight propagation path signal; denotes the second delay cross-correlation; denotes the second RF component signal; denotes the second RF component delay signal; is the second RF component delay cross-correlation noise; is the number of antenna elements; denotes the cross-correlation of the radiation pattern of the first RF component signal; denotes the cross-correlation of the radiation pattern of the second RF component signal; Represents an intermediate variable; Represents a delay intermediate variable.
[0019] Preferably, the cumulative result is expressed as:
[0020] In the formula, Represents the cumulative result; Is the total number of time code elements; Is the third cross-correlation after phase compensation; Is the first cross-correlation after phase compensation; Is the second cross-correlation after phase compensation; Is the number of antenna array elements; Represents the cross-correlation of the first RF component signal and the first RF component signal With a time code element delay; Represents the cross-correlation of the second RF component signal and the second RF component signal With a time code element delay.
[0021] Preferably, the phase of the extracted cumulative result is used to estimate the direction of arrival of the signal according to the phase of the cumulative result, and the calculation formula is as follows:
[0022]
[0023] In the formula, Represents the direction of arrival in the beam domain; Is the cumulative result, Is the direction of arrival of the narrowband line-of-sight propagation path signal incident on the array, Represents the estimated value of the direction of arrival in the beam domain; Is the antenna element spacing, Is the signal wavelength; the antenna element spacing Is the signal wavelength Half of.
[0024] In a second aspect, the present application discloses a hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation method, which is implemented based on the hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation system described in any one of the above, and includes: A single-array dual-RF hybrid analog-digital array receives a signal and sends the received signal to the RF component; The RF component receives signals from a hybrid analog-to-digital array of a single array with dual RFs, and converts and modulates the signals to obtain RF component signals. Among them, the RF component includes a first RF component and a second RF component; the RF component signals include a first RF component signal and a second RF component signal; the first RF component converts and modulates to obtain a first RF component signal; the second RF component converts and modulates to obtain a second RF component signal. The calculation module calculates the first cross-correlation and the first delay cross-correlation between the first RF component signals, calculates the second cross-correlation and the second delay cross-correlation between the second RF component signals, calculates the third cross-correlation between the first RF component signals and the second RF component signals, accumulates the first cross-correlation, the first delay cross-correlation, the second cross-correlation, the second delay cross-correlation and the third cross-correlation to obtain an accumulation result; extracts the phase of the accumulation result, and estimates the direction of arrival of the signal according to the phase of the accumulation result.
[0025] Preferably, the following formula is used to calculate the first cross-correlation, the second cross-correlation and the third cross-correlation:
[0026]
[0027]
[0028] In the formula, denotes the cross-correlation between the RF component signal and the RF component signal; denotes the RF component signal; denotes the RF component signal; the superscript * denotes the complex conjugate; is the additive white Gaussian noise; is the sum of the cross-correlation between the additive white Gaussian noise and the received signal; denotes the narrowband line-of-sight propagation path signal; denotes the cross-correlation of the radiation patterns of different RF component signals; is the radiation pattern of the RF component signal; is the radiation pattern of the RF component signal; is the Doppler frequency; is the index of the time-domain symbol.
[0029] Preferably, the following formula is used to calculate the first delay cross-correlation and the second delay cross-correlation:
[0030] In the formula, Represents the first delay cross-correlation; Represents the first RF component signal; Represents the first RF component delay signal; the superscript * represents the complex conjugate; Is the first RF component delay cross-correlation noise; Represents the narrowband line-of-sight propagation path signal; Represents the second delay cross-correlation; Represents the second RF component signal; Represents the second RF component delay signal; Is the second RF component delay cross-correlation noise; Is the number of antenna array elements; Represents the cross-correlation of the radiation pattern of the first RF component signal; Represents the cross-correlation of the radiation pattern of the second RF component signal; Represents an intermediate variable; Represents a delay intermediate variable; Said intermediate variable , specifically represented as ; Said delay intermediate variable , specifically represented as .
[0031] Compared with the prior art, the present invention has the following beneficial effects: 1) This application adopts a single-array dual-RF hybrid analog-digital array structure, which greatly reduces the number of antenna array elements and RF components, saves the physical structure cost of the array, and solves the problems such as low utilization rate of the antenna array; 2) This application simulates the beamformer with time-domain code elements and the number of antenna array elements as parameters, and this simulation beamforming scheme is simpler and more efficient than the existing simulation beamforming schemes; 3) The operation method of accumulating the cross-correlation of different RF components, the self-cross-correlation of the same RF components, and their respective delay cross-correlation results in a single array improves the signal-to-noise ratio and amplitude of the calculation results, avoids complex symbol correction algorithms and phase ambiguities, and greatly improves the estimation efficiency and accuracy of DOA (Direction of Arrival). BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0033] Figure 1 This is a schematic flowchart of a hybrid modulus time-domain cross-correlation direction-of-arrival estimation method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a single-array dual-radio-frequency hybrid modulus array structure according to an embodiment of the present invention; Figure 3 This is a beam angle diagram of an analog beamformer in different time-domain symbols according to an embodiment of the present invention; Figure 4 This is a comparison diagram of DOA (Direction of Arrival) estimation angles and true angles under different signal-to-noise ratios according to an embodiment of the present invention; Figure 5 This is an experimental result diagram according to an embodiment of the present invention. Detailed implementation manners
[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention described and illustrated herein generally may be arranged and designed in a variety of different configurations.
[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.
[0036] It should be noted that: like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0037] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships in which the products of the invention are customarily placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated devices or elements must have specific orientations, be constructed and operated in specific orientations, and thus should not be construed as limiting the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.
[0038] In addition, when the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.
[0039] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, when the terms "arranged", "installed", "connected", and "coupled" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.
[0040] The present invention will be further described in detail below with reference to the accompanying drawings: The present application discloses a hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation system, which mainly completes the DOA estimation of linear hybrid analog-digital array signals and can be used for channel state information estimation of millimeter-wave massive MIMO and target recognition of radar signals in the field of wireless communication. The system specifically includes: A single-array dual-radio-frequency hybrid analog-digital array for receiving signals and sending the received signals to the radio-frequency component; The radio-frequency component is used to receive the signals from the single-array dual-radio-frequency hybrid analog-digital array, convert and modulate the received signals to obtain radio-frequency component signals, and transmit the radio-frequency component signals to the calculation module; wherein, the radio-frequency component includes a first radio-frequency component and a second radio-frequency component; the first radio-frequency component converts and modulates to obtain a first radio-frequency component signal; the second radio-frequency component converts and modulates to obtain a second radio-frequency component signal; A calculation module is used to calculate the first cross-correlation and the first delayed cross-correlation between the first radio frequency component signals, calculate the second cross-correlation and the second delayed cross-correlation between the second radio frequency component signals, calculate the third cross-correlation between the first radio frequency component signals and the second radio frequency component signals, accumulate the first cross-correlation, the first delayed cross-correlation, the second cross-correlation, the second delayed cross-correlation and the third cross-correlation to obtain an accumulation result; extract the phase of the accumulation result, and estimate the direction of arrival of the signal according to the phase of the accumulation result. The present invention adopts a single-array dual-radio-frequency hybrid analog-digital array, designs an analog beamforming scheme with specific time-domain code elements and the number of antenna elements as parameters, and uses operations such as single-array time-domain correlation to estimate the DOA (Direction of Arrival). The designed analog beamforming scheme is simpler and more efficient than the existing analog beamforming schemes; the use of operations such as single-array time-domain correlation improves the signal-to-noise ratio and amplitude of the calculation result, avoids complex symbol correction algorithms and phase ambiguities, and greatly improves the estimation efficiency and accuracy of the DOA (Direction of Arrival).
[0041] In some embodiments, referring to Figure 2 , the single-array dual-radio-frequency hybrid analog-digital array includes antenna elements, and these antenna elements form a single array; the first radio frequency component is connected to the first antenna elements, and the second radio frequency component is connected to all
[0042] antenna elements. Figure 2 In some embodiments, shows the preset single-array dual-radio-frequency hybrid analog-digital array, a single uniformly spaced linear large-scale phase shifter hybrid array. This single array contains antenna elements. The spacing between the antenna elements is , which is half of the signal wavelength The single array is linearly arranged. This single array is connected to two radio frequency components to implement functions such as up-conversion mixing, filtering, ADC / DAC (Analog-to-Digital Converter / Digital-to-Analog Converter), etc. The first radio frequency component is connected to the first antenna elements, and the second radio frequency component is connected to all
[0043] antenna elements, and the analog beamformer forms an analog beam. Each antenna element is also connected to an analog beamformer, which is used to form an analog beam according to the values of two parameters: the number of antenna elements and the time-domain symbol. This analog beamformer is simpler and more efficient than existing analog beamforming schemes, specifically expressed as:
[0044] In the formula, represents the analog beamformer connected to the th antenna element; represents the analog beam of the th time-domain symbol; is the index of the time-domain symbol; is the index of the antenna element; is the number of antenna elements.
[0045] In some embodiments, in the calculation module, the cross-correlation between radio frequency component signals is calculated. By using operation methods such as single-array time-domain correlation, the signal-to-noise ratio and amplitude of the calculation result are improved, complex symbol correction algorithms and phase ambiguities are avoided, and the estimation efficiency and accuracy of DOA (Direction of Arrival) are greatly improved. The first cross-correlation, the second cross-correlation, and the third cross-correlation are specifically calculated using the following formula:
[0046]
[0047]
[0048] In the formula, represents the cross-correlation between the radio frequency component signal and the radio frequency component signal; represents the radio frequency component signal; represents the radio frequency component signal; the superscript * represents complex conjugate; is the additive white Gaussian noise; is the sum of the cross-correlation between the additive white Gaussian noise and the received signal; represents the narrowband line-of-sight propagation path signal; represents the cross-correlation between the radiation patterns of different radio frequency component signals; is the radiation pattern of the radio frequency component signal; is the radiation pattern of the radio frequency component signal; is the Doppler frequency; is the index of the time-domain symbol, Indicates the direction of arrival in the beam domain.
[0049] In some embodiments, the first delay cross-correlation and the second delay cross-correlation are calculated using the following formula:
[0050] In the formula, Indicates the first delay cross-correlation; Indicates the first RF component signal; Indicates the first RF component delayed signal; the superscript * represents the complex conjugate; Is the first RF component delay cross-correlation noise; Indicates the narrowband line-of-sight propagation path signal; Indicates the second delay cross-correlation; Indicates the second RF component signal; Indicates the second RF component delayed signal; Is the second RF component delay cross-correlation noise; Is the number of antenna elements; Indicates the cross-correlation of the radiation pattern of the first RF component signal; Indicates the cross-correlation of the radiation pattern of the second RF component signal; Indicates an intermediate variable; Indicates a delayed intermediate variable; The intermediate variable , specifically expressed as ; The delayed intermediate variable , specifically expressed as .
[0051] In some embodiments, the cumulative result is expressed as:
[0052] In the formula, Indicates the cumulative result; Is the total number of time symbols; Is the third cross-correlation after phase compensation; Is the first cross-correlation after phase compensation; Is the second cross-correlation after phase compensation; Is the number of antenna elements; Indicates the cross-correlation between the first RF component signal and the first RF component signal with a time symbol delay of Indicates the cross-correlation between the second RF component signal and the second RF component signal with a time symbol delay of
[0053] Further preferably, the phase of the extraction cumulative result is used to estimate the direction of arrival of the signal according to the phase of the cumulative result, and the calculation formula is as follows:
[0054]
[0055] In the formula, represents the direction of arrival estimation in the beam domain; is the cumulative result, is the direction of arrival of the narrowband line-of-sight propagation path signal incident on the array, represents the estimated value of the direction of arrival in the beam domain; is the antenna element spacing, is the signal wavelength; the antenna element spacing is the signal wavelength is half of
[0056] In some embodiments, a method for representing the signal model is determined: The millimeter-wave massive MIMO (Multiple-Input Multiple-Output) communication channel is dominated by LoS (Line-of-Sight). Assuming that the direction of arrival of the narrowband LoS signal incident on the array is , according to Figure 2 the arrangement of the array, for two radio frequency components in the array, here the first radio frequency component signal and the second radio frequency component signal are used to represent the first radio frequency component signal and the second radio frequency component signal respectively; then the received signals of the first radio frequency component signal and the second radio frequency component signal can be respectively expressed as (1) In the formula, is the Doppler frequency, which is generated by the relative movement between the transmitter and the receiver. represents the radio frequency component; is AWGN (Additive White Gaussian Noise), represents the radiation pattern of the radio frequency component signal; The radiation pattern of the radio frequency component signal is determined by the analog beam former. According to the different connection methods of the two radio frequency components, the radiation pattern of the first radio frequency component signal and the radiation pattern (2) (3) In the formula, is the radiation pattern of the nth antenna element of a single array, which is 1 when considering an omnidirectional and uniformly radiating antenna. represents the value of the analog beamformer connected to this antenna element. represents the direction of arrival (DOA) in the beam domain, and the correspondence with is as follows:[[]] (4) is the direction of arrival of the signal incident on the array through the narrowband line-of-sight propagation path, is the antenna element spacing, is the signal wavelength; is the signal wavelength half of.
[0057] Design the analog beamformer:[[]] The analog beamformer designed in the present invention only takes the time-domain symbol and the number of antenna elements as parameters, and its mathematical expression can be represented as (5) In the formula, represents the analog beamformer connected to the th antenna element; represents the analog beam of the th time-domain symbol; is the index of the time-domain symbol; is the index of the antenna element; is the number of antenna elements, and the value ranges of both are .
[0058] Formula (6) shows that the period of is evenly divided by different analog beams. As increases to the array traverses all the beams, and when it repeats cyclically. Figure 3 shows the situation of analog beamforming. When the beam angle of the analog beamformer is °, and so on, traversing 16 beam angles. Similarly, if has a larger value, there are more beam angles in one period, so the estimation result of DOA (Direction of Arrival) is also more accurate. However When it reaches a certain level, the impact on the accuracy of DOA (Direction of Arrival) estimation will be very small.
[0059] In some embodiments, the cross-correlation calculation of different RF components in the time domain: The cross-correlation of RF components in the array can be expressed as (6) In the formula, represents the RF component signal; represents the RF component signal; represents the cross-correlation of the radiation patterns of different RF component signals; . The superscript * represents the complex conjugate, is the additive white Gaussian noise; is the sum of the cross-correlation between the additive white Gaussian noise and the received signal, and can be expressed as (7) According to Figure 2 's array structure and Figure 3 the analog beamforming scheme shown, formulas (2) and (3) can be rewritten as (8) (9) In the formula, the intermediate variable can be expressed as (10) (a) The third cross-correlation and phase compensation between the first RF component signal and the second RF component signal According to formula (6), the third cross-correlation can be expressed as (11) In the formula 's expression is (12) Because is known, use to compensate the third cross-correlation to obtain the cross-correlation of the first RF component signal and the second RF component signal after phase compensation . Ignoring the influence of noise, at this time, the cross-correlation of the first RF component signal and the second RF component signal after phase compensation .
[0060] (b) Cross-correlation and phase compensation of the first RF component signal and the second RF component signal respectively Similarly, according to Equation (6), after the cross-correlation of the first RF component signal and the second RF component signal respectively and can be expressed as (13) (14) Similarly, in the formula and The expressions of are (15) (16) At this time, the phase of the first cross-correlation and the second cross-correlation is both , but when the first cross-correlation and the second cross-correlation reach the peak value, the intermediate variable . When , The simulated beam of the time-domain symbol , at this time use to compensate the phase of the first cross-correlation and the second cross-correlation so that the cross-correlation of the first RF component signal after phase compensation , the cross-correlation of the second RF component signal after phase compensation ; ignoring the influence of noise, at this time the cross-correlation of the first RF component signal after phase compensation and the cross-correlation of the second RF component signal after phase compensation The phase is . When , , because and , and because the value range of directly extracting the phase is , so at this time the cross-correlation of the first RF component signal after phase compensation and the cross-correlation of the second RF component signal after phase compensation The phase is .
[0061] (c) First delayed cross-correlation and second delayed cross-correlation and phase compensation Similarly, according to Equation (6), the first RF component signal and the second RF component signal with their respective After the cross-correlation with the time symbol delay of and Can be expressed as
[0062] If is odd, the cross - correlation of the radiation pattern of the first RF component in can be expressed as , can be expressed as , , and so on. Due to the periodicity of the trigonometric function, finally, the cross - correlation of the radiation pattern of the first RF component and the cross - correlation of the radiation pattern of the second RF component have expressions respectively as
[0063] When it is even, take the negative. If is odd, use and to compensate the phase, when it is even, use and to compensate the phase. The cross - correlation of the first RF component signal with the first RF component signal with a time - code - element delay of and the cross - correlation of the second RF component signal with the second RF component signal with a time - code - element delay of Finally, the result of the extracted phase is the same as that in step (b).
[0064] In the formula, represents the first delay cross - correlation; represents the first RF component signal; represents the first RF component delay signal; the superscript * represents the complex conjugate; is the first RF component delay cross - correlation noise; represents the narrow - band line - of - sight propagation path signal; represents the second delay cross - correlation; represents the second RF component signal; represents the second RF component delay signal; is the second RF component delay cross - correlation noise; is the number of antenna elements; represents the cross - correlation of the radiation pattern of the first RF component; represents the cross - correlation of the radiation pattern of the second RF component; represents an intermediate variable; represents a delay intermediate variable.
[0065] In some embodiments, the accumulation of the above various cross-correlation results.
[0066] Due to the influence of noise, extracting the phase alone will lead to inaccurate estimation results due to the low signal-to-noise ratio. To improve the accuracy, it is necessary to accumulate various cross-correlation results to increase the signal-to-noise ratio of the calculation results. It can be expressed as
[0067] In the formula, represents the accumulated result; is the total number of time symbols; is the third cross-correlation after phase compensation; is the first cross-correlation after phase compensation; is the second cross-correlation after phase compensation; is the number of antenna array elements; represents the cross-correlation between the first radio frequency component signal and the first radio frequency component signal with a time symbol delay of represents the cross-correlation between the second radio frequency component signal and the second radio frequency component signal with a time symbol delay of
[0068] Further preferably, directly extract the phase of the above accumulated result to estimate , and finally use the relationship of formula (4) to calculate the direction of arrival of the narrowband line-of-sight propagation path signal incident on the array.
[0069]
Embodiment
[0070] 1. Simulation conditions The present invention is simulated using MATLAB2020b developed by MathWorks, Inc. in the operating system of Inter(R) Core(TM) i5-12400F 2.50GHz CPU, NVIDIA4060Ti GPU, and Windows11 22631.4602.
[0071] The methods compared in the experiment are as follows: The first is the DOA (Direction of Arrival) estimation method based on MCC (Maximum Cross-Correlation), and the second is the DOA (Direction of Arrival) estimation method based on BSA (Beam Sweeping Algorithm); Simulation content: To verify the present invention, the estimation results of the signal-to-noise ratio from -10 to 10 are experimentally simulated, and the angular range is , as Figure 4 shown.
[0072] From Figure 4 it can be clearly observed that the hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation method disclosed by the present invention can accurately estimate the direction of arrival of the signal.
[0073] Due to the different structures of various DOA (Direction of Arrival) estimation methods, the hardware conditions of the comparative experiments cannot be exactly the same. Calculate the mean squared error (MSE) of DOA (Direction of Arrival) estimation under different signal-to-noise ratios (SNRs, Signal-to-Noise Ratios), and compare it with the MCC (Max-imum Cross-Correlation) method and the BSA (Beam Sweeping Algorithm) method. The results are as Figure 5 shown. At this time, the number of antenna array elements , the maximum value of the time code element , and the direction of arrival of the signal is random. It should be noted that in the MCC (Max-imum Cross-Correlation) method, although the total number of antenna array elements , but multiple sub-arrays and RF components are required, and the number of its sub-arrays is 5. While the present invention only requires one array and two RF components, so the MCC (Max-imum Cross-Correlation) method is higher than the present invention in terms of structural cost.
[0074] From the experimental result graph, it can be observed that the mean squared error (MSE) of the estimation results of the estimation method proposed by the present invention is lower than several existing methods when the total number of antenna arrays is small.
[0075] See Figure 1 , the present invention also discloses a hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation method, which is implemented based on the hybrid analog-digital time-domain cross-correlation direction-of-arrival estimation system described in any one of the above, and includes: S1: A single-array dual-RF hybrid analog-digital array receives signals and sends the received signals to the RF components; S2: The RF component receives the signals from the hybrid analog-to-digital array of a single array with dual RF, and converts and modulates the signals to obtain RF component signals. Among them, the RF component includes a first RF component and a second RF component; the RF component signals include a first RF component signal and a second RF component signal; the first RF component converts and modulates to obtain the first RF component signal; the second RF component converts and modulates to obtain the second RF component signal; S3: The calculation module calculates the first cross-correlation and the first delay cross-correlation between the first RF component signals, calculates the second cross-correlation and the second delay cross-correlation between the second RF component signals, calculates the third cross-correlation between the first RF component signals and the second RF component signals, accumulates the first cross-correlation, the first delay cross-correlation, the second cross-correlation, the second delay cross-correlation and the third cross-correlation to obtain an accumulation result; extracts the phase of the accumulation result, and estimates the direction of arrival of the signal according to the phase of the accumulation result.
[0076] In some embodiments, in the S2, the following formula is used to calculate the first cross-correlation, the second cross-correlation and the third cross-correlation:
[0077]
[0078]
[0079] In the formula, represents the cross-correlation between the RF component signal and the RF component signal; represents the RF component signal; represents the RF component signal; the superscript * represents complex conjugate; is the additive white Gaussian noise; is the sum of the cross-correlation between the additive white Gaussian noise and the received signal; represents the narrowband line-of-sight propagation path signal; represents the cross-correlation of the radiation patterns of different RF component signals; is the radiation pattern of the RF component signal; is the radiation pattern of the RF component signal; is the Doppler frequency; is the index of the time-domain symbol, represents the direction of arrival in the beam domain.
[0080] In some embodiments, the following formula is used to calculate the first delay cross-correlation and the second delay cross-correlation in the S2:
[0081] In the formula, represents the first delayed cross-correlation; represents the first radio frequency component signal; represents the first radio frequency component delayed signal; the superscript * represents the complex conjugate; is the first radio frequency component delayed cross-correlation noise; represents the narrowband line-of-sight propagation path signal; represents the second delayed cross-correlation; represents the second radio frequency component signal; represents the second radio frequency component delayed signal; is the second radio frequency component delayed cross-correlation noise; is the number of antenna array elements; represents the cross-correlation of the radiation pattern of the first radio frequency component signal; represents the cross-correlation of the radiation pattern of the second radio frequency component signal; represents an intermediate variable; represents a delayed intermediate variable.
[0082] RF (Radio Frequency): In the fields of electronics and communication, RF usually refers to radio frequency, which is a frequency range of electromagnetic radiation and is commonly used in wireless communication, such as radio broadcasting, television broadcasting, mobile communication, etc.
[0083] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.
Claims
1. A hybrid modulus-time domain cross-correlation direction-of-arrival estimation system, characterized in that: include: A single-array dual-RF hybrid analog-to-digital array is used to receive signals and send the received signals to the RF component; The RF component is used to receive a signal from a single-array dual-RF hybrid analog-to-digital array, convert and modulate the received signal to obtain an RF component signal, and transmit the RF component signal to the computing module; wherein the RF component includes a first RF component and a second RF component; the first RF component converts and modulates to obtain a first RF component signal; the second RF component converts and modulates to obtain a second RF component signal; A calculation module is used to calculate the first mutual correlation and the first delayed mutual correlation between the first RF component signals, calculate the second mutual correlation and the second delayed mutual correlation between the second RF component signals, calculate the third mutual correlation between the first RF component signal and the second RF component signal, accumulate the first mutual correlation, the first delayed mutual correlation, the second mutual correlation, the second delayed mutual correlation and the third mutual correlation to obtain a cumulative result; extract the phase of the cumulative result, and estimate the direction of arrival of the signal based on the phase of the cumulative result.
2. A hybrid analog-to-digital time domain cross-correlation direction of arrival estimation system according to claim 1, characterized in that: The single array dual radio frequency hybrid analog-to-digital array comprises Antenna array elements, The antenna array elements form a single array; the first radio frequency component and the front The second RF component is connected to all antenna elements. The antenna elements are connected.
3. The hybrid analog-to-digital time domain cross-correlation direction of arrival estimation system according to claim 2, characterized in that: The single array Each antenna array element is also connected to an analog beamformer, and the analog beamformer is used to form an analog beam according to the values of two parameters, the number of antenna array elements and the time domain code element; The analog beamformer is represented as: In the formula, Indicates An analog beamformer with antenna elements connected together; Indicates A simulated beam of time-domain symbols; is the index of the time domain symbol; is the index of the antenna element; is the number of antenna array elements.
4. The hybrid analog-to-digital time domain cross-correlation direction of arrival estimation system according to claim 1, characterized in that: The first, second and third cross-correlations are calculated using the following formula: In the formula, express RF component signals and Cross-correlation of RF component signals; express RF component signals; express RF component signals; The superscript * indicates complex conjugation; is additive white Gaussian noise; is the sum of the cross-correlations between the additive white Gaussian noise and the received signal; Represents a narrowband line-of-sight propagation path signal; Represents the cross-correlation of signal radiation patterns of different RF components; yes The radiation pattern of the RF component signal; yes The radiation pattern of the RF component signal; is the Doppler frequency; is the index of the time domain symbol, Indicates the direction of arrival of the beam domain.
5. The hybrid analog-to-digital time domain cross-correlation direction of arrival estimation system according to claim 1, characterized in that: The first delay cross-correlation and the second delay cross-correlation are calculated using the following formula: In the formula, represents the first time-delay cross-correlation; represents a first radio frequency component signal; Indicates the delay signal of the first radio frequency component; The superscript * indicates complex conjugation; is the delayed cross-correlation noise of the first RF component; Represents a narrowband line-of-sight propagation path signal; represents the second time-delay cross-correlation; represents a second radio frequency component signal; Indicates the delay signal of the second radio frequency component; is the delayed cross-correlation noise of the second RF component; is the number of antenna array elements; representing a cross-correlation of a radiation pattern of a signal of the first radio frequency component; representing a cross-correlation of a radiation pattern of a signal of a second radio frequency component; represents an intermediate variable; Represents a delayed intermediate variable.
6. The hybrid modulus-time domain cross-correlation direction of arrival estimation method according to claim 3, characterized in that: The cumulative result is expressed as: In the formula, Indicates cumulative results; is the total number of time code units; is the third cross-correlation after phase compensation; is the first cross-correlation after phase compensation; is the second cross correlation after phase compensation; is the number of antenna array elements; Indicates the first RF component signal and the first RF component signal Cross-correlation of time symbol delays; Indicates the second RF component signal and the second RF component signal The cross-correlation of the time symbol delays.
7. The hybrid modulus-time domain cross-correlation direction of arrival estimation method according to claim 1, characterized in that: The phase of the cumulative result is extracted, and the direction of arrival of the signal is estimated according to the phase of the cumulative result. The calculation formula is as follows: In the formula, represents the direction of arrival of the beam domain; To accumulate the results, is the direction of arrival of the signal incident on the array in the narrowband line-of-sight propagation path, represents the estimated value of the beam domain arrival direction; is the antenna element spacing, is the signal wavelength; the antenna element spacing is the signal wavelength half.
8. A hybrid modulus-time domain cross-correlation direction of arrival estimation method, implemented based on the hybrid modulus-time domain cross-correlation direction of arrival estimation system according to any one of claims 1 to 7, characterized in that: include: The single array dual RF hybrid analog-to-digital array receives the signal and sends the received signal to the RF component; The RF component receives a signal from a single-array dual-RF hybrid analog-to-digital array, and converts and modulates the signal to obtain a RF component signal, wherein the RF component includes a first RF component and a second RF component; the RF component signal includes a first RF component signal and a second RF component signal; the first RF component converts and modulates to obtain a first RF component signal; the second RF component converts and modulates to obtain a second RF component signal; The calculation module calculates the first mutual correlation and the first delayed mutual correlation between the first RF component signals, calculates the second mutual correlation and the second delayed mutual correlation between the second RF component signals, calculates the third mutual correlation between the first RF component signal and the second RF component signal, accumulates the first mutual correlation, the first delayed mutual correlation, the second mutual correlation, the second delayed mutual correlation and the third mutual correlation to obtain a cumulative result; extracts the phase of the cumulative result, and estimates the direction of arrival of the signal based on the phase of the cumulative result.
9. The hybrid modulus-time domain cross-correlation direction of arrival estimation method according to claim 8, characterized in that: The first, second and third cross-correlations are calculated using the following formula: In the formula, express RF component signals and Cross-correlation of RF component signals; express RF component signals; express RF component signals; The superscript * indicates complex conjugation; is additive white Gaussian noise; is the sum of the cross-correlations between the additive white Gaussian noise and the received signal; Represents a narrowband line-of-sight propagation path signal; Represents the cross-correlation of signal radiation patterns of different RF components; yes The radiation pattern of the RF component signal; yes The radiation pattern of the RF component signal; is the Doppler frequency; is the index of the time domain symbol.
10. The hybrid modulus-time domain cross-correlation direction of arrival estimation method according to claim 8, characterized in that: The first delay cross-correlation and the second delay cross-correlation are calculated using the following formula: In the formula, represents the first time-delay cross-correlation; represents a first radio frequency component signal; Indicates the delay signal of the first radio frequency component; The superscript * indicates complex conjugation; is the delayed cross-correlation noise of the first RF component; Represents a narrowband line-of-sight propagation path signal; represents the second time-delay cross-correlation; represents a second radio frequency component signal; Indicates the delay signal of the second radio frequency component; is the delayed cross-correlation noise of the second RF component; is the number of antenna array elements; representing a cross-correlation of a radiation pattern of a signal of the first radio frequency component; representing a cross-correlation of a radiation pattern of a signal of a second radio frequency component; represents an intermediate variable; Represents a delayed intermediate variable.