A millimeter wave frequency band joint communication and positioning beam forming method

Abstract

The application relates to a millimeter wave frequency band combined communication and positioning beam forming method, which comprises the following steps: a base station and a user establish communication, and realize communication functions based on a mature wireless communication system, and meanwhile, the system can obtain real-time channel state information; meanwhile, the base station estimates the user position according to the channel state information, and can design uplink and downlink beam forming schemes in the current situation according to the channel state, so that higher system throughput and positioning accuracy can be realized in the next round of transmission. The application has the beneficial effects that the application can realize the two functions of positioning and communication in a unified frequency band, and through continuous iteration and optimization of the working mode, the real-time positioning accuracy and the communication rate are improved to meet the system requirements.

Description

Technical Field

[0001] This invention relates to the field of wireless millimeter-wave communication technology, and more specifically, to a beamforming method for joint communication and positioning in the millimeter-wave band. Background Technology

[0002] With the development of intelligent navigation and autonomous driving technologies, vehicle positioning technology is becoming increasingly crucial. For intelligent navigation systems, accurate route planning requires not only accurate measurement of the vehicle's own position but also continuous communication with a remote central control tower to obtain real-time traffic information. Currently, vehicle positioning is typically achieved through satellite positioning, with an accuracy of around 5 meters, which is insufficient to meet the needs of autonomous driving.

[0003] In addition, existing vehicle positioning solutions require two sets of hardware devices, a communication system and a positioning system, which results in high hardware costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a beamforming method for joint communication and positioning in the millimeter-wave band.

[0005] In communication systems that utilize channel state information for positioning, traditional beamforming schemes tend to distribute signal power across multiple paths to increase channel capacity, while positioning requires maximizing power along the line-of-sight path. To address this issue, this invention proposes a joint communication and positioning beamforming method under millimeter-wave conditions, which can dynamically beamform while simultaneously meeting communication and positioning requirements, resulting in more accurate positioning estimates.

[0006] Firstly, a beamforming method for joint communication and positioning in the millimeter-wave band is provided, including:

[0007] Step 1: The base station is equipped with multiple antennas, and the user is equipped with a single antenna. The user sends pilot data to the base station. The base station receives the pilot data, completes channel estimation, obtains the current channel state information, and uses parameter estimation methods to estimate the transmission angle, reception angle, and delay information of the uplink line-of-sight path signal. Based on the fixed position of the base station at this time, the user's location information is calculated.

[0008] Step 2: The base station determines the optimal beamforming scheme under the current conditions based on the channel state information and the receiving and transmitting angles of the uplink line-of-sight path signal.

[0009] Step 3: The base station sends the beamforming scheme to the user in the downlink cycle, and at the same time, the base station adjusts its own working state according to the beamforming scheme to prepare to receive the signal transmitted by the user in the next cycle.

[0010] Step 4: The user receives the signal from the base station and obtains the channel state information at this time. Then, the receiving angle, transmitting angle, and delay of the downlink line-of-sight path signal are estimated, and the relative position relationship between the user and the base station is calculated. The position estimate of the fused uplink and downlink information is obtained by weighting the calculation results of the base station and the calculation results of the user.

[0011] Step 5: The user adjusts their working state according to the beamforming scheme and starts the next transmission cycle, returning to Step 1.

[0012] Preferably, in step 1, the parameter estimation method includes a multi-signal classification algorithm and a signal parameter estimation algorithm based on rotation invariance.

[0013] As a preferred option, in step 2, the base station also optimizes the beamforming scheme according to the communication performance requirements and positioning performance requirements.

[0014] Preferably, in step 4, the weighted average of the uplink and downlink estimated locations based on the calculation results of the base station and the user includes: taking the average of the uplink estimated location and the downlink estimated location, or taking a weighted average based on the signal-to-noise ratio of the uplink signal and the downlink signal.

[0015] Preferably, in step 4, obtaining the channel state information at this time includes: performing channel estimation on the signal from the base station to obtain the channel state information, or using the channel state information in step 1 as the channel state information at this time.

[0016] In a second aspect, a beamforming system for millimeter-wave band joint communication and positioning is provided for performing the beamforming method for millimeter-wave band joint communication and positioning described in the first aspect, comprising: a base station and at least one user, wherein the base station is equipped with multiple antennas, the user is equipped with a single antenna, and a communication connection is established between the base station and the user.

[0017] Thirdly, a computer storage medium is provided, wherein a computer program is stored therein; when the computer program is run on a computer, the computer executes the beamforming method for millimeter-wave band joint communication and positioning described in the first aspect.

[0018] The beneficial effects of this invention are: this invention can realize both positioning and communication functions in a unified frequency band, and improves real-time positioning accuracy and communication rate to meet system requirements by continuously iterating and optimizing the working mode; the real-time iterative working mode of this system can achieve continuous high-precision tracking of the user's location; this invention can complete the calculation of the above-mentioned optimal working mode in a short time through a fast algorithm for beamforming design, and based on this result, the system can save a lot of computing resources. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system architecture for the application scenarios to which this invention applies;

[0020] Figure 2 This is a flowchart of the user and base station system workflow used in this invention;

[0021] Figure 3 This is a comparison chart of the positioning accuracy of mobile users and fixed users in the simulation of this invention. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0023] Example 1:

[0024] A beamforming system for joint communication and positioning in the millimeter-wave band includes: a base station and at least one user, the base station being equipped with multiple antennas, the user being equipped with a single antenna, and a communication connection between the base station and the user.

[0025] For example, the user is equipped with multiple antennas, such as 16 millimeter-wave antennas, and can adjust its own status in real time according to the working mode transmitted back by the base station.

[0026] The base station, equipped with numerous antennas, such as 64 millimeter-wave antennas, enables wireless communication with user terminals. It also performs channel estimation and can freely read real-time channel information. Furthermore, the base station is equipped with a positioning parameter estimation algorithm that can calculate signal delay, transmission angle, and reception angle from channel information, and stores the exact location of the base station. It can also calculate the user's coordinates using geometric relative positions. Finally, based on the algorithm of this invention, the system can transmit the calculated operating mode back to the user terminal and adjust its own operating mode to await the next transmission cycle.

[0027] Both the base station and the user are equipped with multiple antennas for communication and sensing. The communication between the user and the base station adopts the time division duplex (TDD) mode. In the multipath model, the system can use algorithms such as MUSIC and Capon to extract the transmit angle and receive angle of each path from the channel state information, calculate the signal delay on each path by using matched filtering, and then obtain the relative coordinates of the user and the base station through geometric calculations.

[0028] Example 2:

[0029] During communication, users need to estimate instantaneous Channel State Information (CSI). Since CSI includes some physical space information, it can be used for user location. The Time of Arrival (TOA), Angle of Arrival (Angle of Arrival), and Angle of Departure (Angle of Departure) between the user and the base station can be extracted from the CSI, and the user's location can be calculated using triangulation. This method integrates the location process into the communication process and requires only one antenna device.

[0030] This invention proposes a beamforming method that integrates communication and positioning in a millimeter-wave frequency band. This method can extract the relative positional relationship between the user and the base station from channel state information, and the positioning results can be used to guide the user's beamforming, maximizing positioning accuracy while meeting communication requirements. This method integrates the positioning component into the communication component, thus eliminating the need for dedicated positioning equipment and significantly reducing hardware costs.

[0031] Specifically, a beamforming method for joint communication and positioning in the millimeter-wave band, such as... Figure 2 As shown, it includes:

[0032] Step 1: The base station is equipped with multiple antennas, and the user is equipped with a single antenna. The user sends pilot data to the base station; the base station receives the pilot data, completes channel estimation, obtains the current channel state information, and uses parameter estimation methods to estimate the transmission angle of the uplink line-of-sight path signal. The receiver angle θ1 and time delay τ1 are used to calculate the user's location information based on the fixed position of the base station at this time.

[0033] Before step 1, the user establishes a communication connection with the base station, enabling the user to send pilot data to the base station. For example, the pilot data transmitted by the user to the base station is the signal of the first cycle.

[0034] In step 1, the parameter estimation methods include multi-signal classification algorithms and signal parameter estimation algorithms based on rotation invariant techniques.

[0035] In step 1, the base station locally stores its own spatial location information. Assuming the coordinates of this location are (X,Y), and taking the orientation of the base station receiving antenna as the positive direction of the Y-axis, the user's coordinates can be calculated as (X+c0τ1sinθ1, Y+c0τ1cosθ1).

[0036] Step 2: The base station determines the optimal beamforming scheme under the current conditions based on the channel state information and the receiving and transmitting angles of the uplink line-of-sight path signal.

[0037] In step 2, the optimal beamforming scheme designed by the base station meets the user's communication needs while maximizing positioning accuracy in its operating mode (including beamforming for uplink and downlink communication in the next cycle and the structure of the transmission frame).

[0038] In step 2, the base station also optimizes the beamforming scheme according to the communication performance requirements and positioning performance requirements, with the goal of simultaneously meeting the communication and positioning needs.

[0039] Step 3: The base station sends the beamforming scheme along with the data to be sent back to the user in the downlink cycle. At the same time, the base station adjusts its own working state according to the beamforming scheme to prepare to receive the signal transmitted by the user in the next cycle.

[0040] Step 4: The user receives the signal from the base station, obtains the channel state information at this time, and then estimates the receiving angle θ2 and the transmitting angle of the downlink line-of-sight path signal. The time delay τ2 is calculated, and the relative position relationship between the user and the base station is calculated. The position estimate of the fused uplink and downlink information is obtained by weighting the calculation results of the base station and the user.

[0041] For example, if a user receives the spatial location coordinates (X, Y) of the base station, the user's coordinates can be calculated as follows:

[0042] In step 4, considering that the uplink and downlink processes are estimated twice, the final position estimate is obtained by weighted fusion. One weighting method is to take the average of the uplink estimated position and the downlink estimated position, or to perform a weighted average based on the signal-to-noise ratio of the uplink and downlink signals.

[0043] In step 4, given the reciprocity between uplink and downlink, the channel information estimated using the uplink can be directly used for the downlink. At this point, the combined uplink and downlink algorithm can degenerate into an uplink-only or downlink-only positioning algorithm, requiring the base station to design a corresponding beamforming optimization scheme. Therefore, there are various ways to obtain the channel state information in step 4, such as performing channel estimation on the signal from the base station to obtain the channel state information, or using the channel state information from step 1 as the current channel state information.

[0044] Step 5: The user adjusts their working status according to the beamforming scheme, starts the next transmission cycle, and returns to Step 1.

[0045] Example 3:

[0046] A beamforming method for joint communication and positioning in the millimeter-wave band estimates the user's location and adjusts the beamforming scheme based on channel state information. Its application scenario system architecture is described below. Figure 1 As shown, the process of this method is as follows: Figure 2As shown. Includes:

[0047] Step 1:

[0048] See Figure 1 Based on a common road model, including a base station deployed beside a highway, with a center frequency fc = 28 GHz, and a single user can be equipped with 10 carrier frequencies Nc. Assume the base station has 64 antennas, the user has 16 antennas, and the time-division duplex cycle is 10 µs. In communication, the signal transmitted by the user will reach the destination base station through multiple paths. The signal received by the base station can be represented as:

[0049]

[0050] Where θ i Let i = 0, 1, ..., L2-1 be the incident angle of the uplink signal, and the corresponding path gain be β. i i = 0, 1, ..., L2-1 This is the guiding vector. △ Rx This is the distance between the receiving antennas after normalizing the signal wavelength. Similarly, As the guiding vector, △ Tx This is the transmit antenna spacing after normalizing the signal wavelength. F is the uplink beamforming matrix, N is Gaussian noise, Y is the received signal, S is the transmitted signal, and τ is the transmit antenna spacing. i ,i=0,1,...,L2-1 is the path delay of the uplink signal.

[0051] The signal strength attenuation for each path is derived from a formula, and the subscript i for different paths is omitted here:

[0052] β=α+10γlog 10 (d)+ξ[dB]

[0053] Where ξ is the variance σ 2 The variables are Gaussian random variables with a mean of 0. For line-of-sight paths, this invention uses α = 61.4, γ = 2, and σ = 5.8; for non-line-of-sight paths, this invention uses α = 72.0, γ = 2.92, and σ = 8.7. In a real-world scenario, there may be a large number of non-line-of-sight paths. To simplify the model, this invention only selects non-line-of-sight paths generated by a single reflection. Usually, multiple reflections will cause the signal of this path to attenuate rapidly, while the signals obtained by the receiver from the line-of-sight path and the single-reflection non-line-of-sight path contain more than 90% of the total signal power that the receiver can receive.

[0054] The actual location deployment of users and base stations, such as Figure 1As shown, the user's transmitting antenna power is 15 dBm, the base station's transmitting power is 65 dBm, and the ambient background noise is -170 dBm. The base station is the origin, the horizontal axis is the x-axis, and the vertical axis is the y-axis. The user's initial position is 500m from the base station, with specific coordinates (-400, 300). In the robustness test of the moving scenario, the user will move in the positive x-axis direction with different initial velocities; otherwise, we assume the user remains at the initial position.

[0055] When a user sends uplink data to the base station, it will simultaneously send its own communication rate requirement C to the user. min .

[0056] Step 2:

[0057] After receiving the user's uplink signal, the base station estimates the uplink channel state information matrix H and calculates the path with the highest power (i.e., the line-of-sight path) using the MUSIC (Multi-Signal Classification) algorithm, taking its receive angle, transmit angle, and delay, and converting them into the corresponding user's relative position. Then, eigenvalue decomposition is performed on the autocorrelation matrix of the channel state information matrix to obtain H. H H = U H ΛU, where the eigenvalue matrix Λ is a diagonal matrix, and the elements on its diagonal are diag(Λ) = [Λ1,Λ2,...,Λ]. n The symbol ] indicates n sub-channels, where n is the number of receiving antennas. The base station designs the beamforming matrix F = U based on this. H Λ F Λ F It is also a diagonal matrix, where the values ​​of the diagonal elements represent the power allocated by beamforming on the sub-channels. To ensure channel capacity while minimizing positioning error, the system maximizes Λ while meeting communication requirements. F The first element of this method can be used to obtain a beamforming matrix that approximates the optimal case.

[0058] Step 3:

[0059] The base station sends the user location estimate obtained in step 2 to the user. The user terminal repeats the location estimation part of step 2 to calculate the location estimate based on the downlink channel state information. Based on the signal-to-noise ratio of the uplink and downlink channels, the reliability of both is obtained, and the uplink-downlink fused user location estimate is obtained by weighting them.

[0060] Step 4:

[0061] Considering two scenarios—a user remaining stationary and a user approaching the base station at a speed of 30 meters per second—the difference in positioning performance is as follows: Figure 3 Both have similar performance, therefore the system can perform user tracking.

Claims

1. A beamforming method for joint communication and positioning in the millimeter-wave band, characterized in that, include: Step 1: The base station is equipped with multiple antennas, and the user is equipped with a single antenna. The user sends pilot data to the base station. The base station receives the pilot data, completes channel estimation, obtains the current channel state information, and uses parameter estimation methods to estimate the transmission angle, reception angle, and delay information of the uplink line-of-sight path signal. It also calculates the user's location information based on the fixed position of the base station at this time. Step 2: Based on the current channel state information and the receiving and transmitting angles of the uplink line-of-sight path signal, the base station determines the optimal beamforming scheme for the current situation; the optimal beamforming scheme designed by the base station is a working mode that meets the user's communication needs while maximizing positioning accuracy. Step 3: The base station sends the beamforming scheme to the user in the downlink cycle, and at the same time, the base station adjusts its own working state according to the beamforming scheme to prepare to receive the signal transmitted by the user in the next cycle. Step 4: The user receives the signal from the base station and obtains the channel state information at this time. Then, the receiving angle, transmitting angle, and delay of the downlink line-of-sight path signal are estimated, and the relative position relationship between the user and the base station is calculated. The position estimate of the fused uplink and downlink information is obtained by weighting the calculation results of the base station and the calculation results of the user. Step 5: The user adjusts their working state according to the beamforming scheme and starts the next transmission cycle, returning to Step 1.

2. The beamforming method for joint communication and positioning in the millimeter-wave band according to claim 1, characterized in that, In step 1, the parameter estimation method includes a multi-signal classification algorithm and a signal parameter estimation algorithm based on rotation invariant technology.

3. The beamforming method for millimeter-wave band joint communication and positioning according to claim 2, characterized in that, In step 2, the base station also optimizes the beamforming scheme based on communication performance requirements and positioning performance requirements.

4. The beamforming method for joint communication and positioning in the millimeter-wave band according to claim 3, characterized in that, In step 4, the location estimation of the fused uplink and downlink information by weighting the calculation results of the base station and the calculation results of the user includes: taking the average of the uplink estimated location and the downlink estimated location, or taking a weighted average based on the signal-to-noise ratio of the uplink signal and the downlink signal.

5. The beamforming method for joint communication and positioning in the millimeter-wave band according to claim 4, characterized in that, In step 4, obtaining the channel state information at this time includes: performing channel estimation on the signal from the base station to obtain the channel state information, or using the channel state information in step 1 as the channel state information at this time.

6. A beamforming system for joint communication and positioning in the millimeter-wave band, characterized in that, The beamforming method for performing millimeter-wave band joint communication and positioning as described in claim 1 includes: a base station and at least one user, wherein the base station is equipped with multiple antennas, the user is equipped with a single antenna, and a communication connection is established between the base station and the user.

7. A computer storage medium, characterized in that, The computer storage medium stores a computer program; when the computer program is run on the computer, it causes the computer to execute the beamforming method for millimeter-wave band joint communication and positioning as described in claim 1.

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