A beamforming method for decoupling logical beams from physical antennas

Abstract

The present invention relates to a beamforming method for decoupling logical beams from physical antennas, comprising: installing a cylindrical array antenna array on a command UAV, estimating the channel state information of the cylindrical array antenna array according to an uplink detection signal transmitted by a task UAV; calculating the signal power of each column of antennas in the cylindrical array antenna array according to the channel state information of the cylindrical array antenna array; selecting the best N columns of adjacent antennas from M columns of antennas, and extracting the channel state information corresponding to the selected N columns of adjacent antennas; obtaining a transmission signal according to the channel state information corresponding to the N columns of adjacent antennas, and commanding the UAV to transmit the transmission signal from the cylindrical array antenna array to the task UAV. The present invention can achieve equal gain seamless coverage in any direction on the horizontal plane, and provide a stable communication link for the command UAV and the task UAV.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more specifically to a beamforming method for decoupling a logical beam from a physical antenna. Background Art

[0002] In unmanned scenarios, there are two types of drones that are essential: command drones and mission drones. Mission drones rush to the scene, collect various intelligence, and then report to the command drone. The command drone is far away from the scene, comprehensively analyzes the intelligence from the mission drone, generates commands, and then sends them to the mission drone. Since the communication distance between the command drone and the mission drone is very long, for example, up to 30 kilometers, the command drone generally uses beamforming to communicate with the mission drone.

[0003] The mission drone and the command drone fly at high speed in the air. For example, the speed of the mission drone relative to the command drone can be as high as 300 kilometers per hour, and its position relative to the command drone changes randomly and rapidly. In order to enable the communication link between the command drone and the mission drone to have the ability to communicate in motion, the beam generated by the command drone needs to cover any direction of the horizontal plane in a timely manner, achieving all-round, equal gain and seamless coverage.

[0004] In order to achieve coverage in any direction on the horizontal plane in unmanned scenarios, two solutions are generally used. Solution 1: Use a parabolic antenna and use a servo motor to drive the antenna to rotate so that the beam is aimed at the tracking target to achieve coverage in any direction on the horizontal plane; Solution 2: Use a civilian 4-panel array antenna to form full coverage on the horizontal plane. However, the beam direction adjustment of Solution 1 is slow, so in high-speed maneuvering scenarios, the mission drone can easily fly away from the area that the beam is about to cover, resulting in an unstable communication link. Solution 2 adjusts the beam direction by adjusting the phase of each antenna signal. Although the beam direction is adjusted quickly, there is a coverage blind spot at the junction of adjacent antenna arrays, which will cause the communication link to be interrupted.

[0005] In addition, in the civilian 5G communication network, the logical beams generated by the antenna array are closely coupled with the physical antennas. For example, the 8-antenna array synthesizes 8 orthogonal beams from left to right, and each beam corresponds to a direction. If the antenna array rotates, the beam direction will rotate accordingly, that is, the logical beam is coupled with the physical antenna. This is disadvantageous in 5G unmanned high-speed maneuvering scenarios. For example, if the command drone is slightly deflected or the antenna array is deflected by the wind, the beam can easily deviate from the communication drone, resulting in interruption of the communication link. Summary of the invention

[0006] In order to solve the above-mentioned problems in the prior art, the present invention provides a beamforming method that decouples the logical beam from the physical antenna, which can achieve seamless coverage of the beam in any direction and provide a stable communication link for the command UAV and the mission UAV.

[0007] The present invention provides a beamforming method for decoupling a logical beam from a physical antenna, comprising:

[0008] Step S1, installing a cylindrical array antenna array on a command UAV, and the command UAV estimates the channel state information of the cylindrical array antenna array according to the uplink detection signal transmitted by the task UAV; the cylindrical array antenna array is composed of M columns of antennas, and the channel state information of the cylindrical array antenna array is stored in a matrix H;

[0009] Step S2, calculating the signal power of each column of antennas in the cylindrical array antenna array according to the channel state information of the cylindrical array antenna array;

[0010] Step S3, selecting the best N columns of adjacent antennas from the M columns of antennas, and extracting the channel state information corresponding to the selected N columns of adjacent antennas;

[0011] Step S4, obtaining a transmission signal according to the channel state information corresponding to the N columns of adjacent antennas, and the command UAV transmits the transmission signal from the cylindrical array antenna array to the task UAV.

[0012] Furthermore, the signal power p of each column of antennas in step S2 is i Calculate according to the following formula:

[0013] p i =||H(:,i)|| 2 ,i=1,2,...,M

[0014] Where H(:,i) represents the i-th column of the matrix H, corresponding to the i-th column antenna in the cylindrical array antenna array.

[0015] Furthermore, the step S3 comprises:

[0016] Step S31, find the antenna column with the largest signal power, and obtain the number i corresponding to the antenna column with the largest signal power max ;

[0017] Step S32, set N=i max , selecting N-1 columns of antennas adjacent to the column of antennas with the largest signal power to form the optimal N columns of adjacent antennas;

[0018] Step S33: Obtain an index set corresponding to the N columns of adjacent antennas, and extract channel state information corresponding to the N columns of adjacent antennas.

[0019] Further, the step S32 includes:

[0020] Step S321, determine whether N is an odd number or an even number, if it is an odd number, proceed to step S322; if it is an even number, proceed to step S323;

[0021] Step S322, selecting n antenna columns on the left and right sides of the antenna column with the largest signal power, where n=(N-1) / 2;

[0022] Step S323, select the antenna on the left of the column with the largest signal power Column antenna, and the N-1-n1 column antenna on the right; among them, Indicates that the variable is rounded down.

[0023] Further, the channel state information corresponding to the N columns of adjacent antennas is extracted according to the following formula:

[0024] H N =H(:,S)

[0025] Where S = {...,i max -1,i max ,i max +1,...}, H(:,S) represents the N columns of the matrix H.

[0026] Furthermore, the step S4 comprises:

[0027] Step S41, performing singular value decomposition on the channel state information corresponding to the N columns of adjacent antennas to obtain H N The eigenvector corresponding to the largest eigenvalue in

[0028] Step S42, setting the shaping vector The data symbol s to be transmitted is weighted by using the assignment vector w to obtain the transmission signal x.

[0029] Further, singular value decomposition is performed on the channel state information corresponding to the N columns of adjacent antennas according to the following formula:

[0030]

[0031] subject to:

[0032] [λ k ,v k ]=SVD(H N ), k=1,2,...,N

[0033] In the formula, SVD represents the matrix H N Perform singular value decomposition to obtain the matrix HN Each eigenvalue and corresponding eigenvector in ; λ k Denotes the matrix H N The kth eigenvalue in k Represents the eigenvector corresponding to the kth eigenvalue.

[0034] The present invention provides a novel beamforming method for decoupling logical beams from physical antennas for unmanned scenarios. The method adopts a cylindrical array antenna and selects a small number of antennas facing the target direction to generate beams. It can achieve equal gain seamless coverage in any direction on the horizontal plane and provide a stable communication link for command drones and mission drones. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a beamforming method for decoupling a logical beam from a physical antenna according to the present invention.

[0036] Figure 2 This is an application scenario of the beamforming method for decoupling a logical beam from a physical antenna according to the present invention. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0038] like Figure 1 As shown, the beamforming method for decoupling a logical beam from a physical antenna provided by the present invention comprises the following steps:

[0039] Step S1, a cylindrical array antenna array is installed on the command UAV, and the command UAV estimates the channel state information (CSI) of the cylindrical array antenna array according to the uplink detection signal transmitted by the task UAV. The cylindrical array antenna array is composed of M columns of antennas. The CSI is stored in a matrix H, where the matrix H has M columns, corresponding to the M columns of antennas in the cylindrical array antenna array; the matrix H has R rows, corresponding to the number of task UAVs.

[0040] Step S2, calculating the signal power of each column of antennas in the cylindrical array antenna array according to the channel state information of the cylindrical array antenna array.

[0041] The signal power of each column of antennas is calculated as follows:

[0042] p i =||H(:,i)|| 2 ,i=1,2,...,M

[0043] Where H(:,i) represents the i-th column of the matrix H, corresponding to the i-th column antenna in the cylindrical array antenna array.

[0044] Step S3, in order to reduce the complexity of singular value decomposition, the best N columns of adjacent antennas are selected from the M columns of antennas to perform beamforming for the mission UAV, and the CSI corresponding to the selected N columns of adjacent antennas is extracted.

[0045] Specifically, step S3 includes:

[0046] Step S31, find the antenna column with the largest signal power, and obtain the number i corresponding to the antenna column with the largest signal power according to the following formula: max :

[0047]

[0048] Step S32, set N=i max , select N-1 columns of antennas adjacent to the column of antennas with the largest signal power to form the optimal N columns of adjacent antennas.

[0049] Because number i max It may be an odd number or an even number, so step S32 includes:

[0050] Step S321, determine whether N is an odd number or an even number, if it is an odd number, proceed to step S322; if it is an even number, proceed to step S323.

[0051] Step S322, selecting n antenna columns on the left and right sides of the antenna column with the largest signal power, where n=(N-1) / 2;

[0052] Step S323, select the antenna on the left of the column with the largest signal power The antenna is a column of antennas, and the N-1-n1 column of antennas on the right. Indicates that the variable is rounded down, for example, It should be understood that the N-1-n1 columns of antennas to the left of the column with the largest signal power and the N-1-n1 columns of antennas to the right may also be selected. Column antenna.

[0053] Step S33, obtaining the optimal index set corresponding to N columns of adjacent antennas, and extracting the CSI corresponding to the N columns of adjacent antennas according to the following formula:

[0054] H N =H(:,S)

[0055] Where S = {...,i max -1,i max ,i max +1,...}, H(:,S) represents the N columns of the matrix H.

[0056] Step S4, according to the CSI corresponding to the selected N columns of adjacent antennas, obtain the transmission signal (i.e. the beam to be transmitted), and command the UAV to transmit the transmission signal from the cylindrical array antenna array to the task UAV.

[0057] Specifically, step S4 includes:

[0058] Step S41: perform singular value decomposition on the CSI corresponding to N columns of adjacent antennas according to the following formula to obtain H N The eigenvector corresponding to the largest eigenvalue in

[0059]

[0060] subject to:

[0061] [λ k ,v k ]=SVD(H N ), k=1,2,...,N

[0062] In the formula, SVD represents the matrix H N Perform singular value decomposition to obtain the matrix H N Each eigenvalue and corresponding eigenvector in ; λ k Denotes the matrix H N The kth eigenvalue in k Represents the eigenvector corresponding to the kth eigenvalue.

[0063] Step S42, setting the shaping vector The data symbol s to be transmitted is weighted by the assignment vector w to obtain the transmitted signal x. Where s is a pre-known data symbol, and the transmitted signal x is calculated according to the following formula:

[0064] x=ws

[0065] The unmanned combat scenario of the present invention is as follows Figure 2 As shown in the figure, the cylindrical array antenna array is installed on the belly of the command drone, and the mission drone maneuvers at high speed relative to the command drone. No matter where the mission drone flies around the command drone, such as the east, south, and west directions in the figure, the command drone can estimate the CSI based on the detection signal emitted by the mission drone, and then select the physical antenna facing the mission drone to generate a beam pointing to the mission drone.

[0066] In the present invention, a beam pointing in a certain direction is generated by a physical antenna currently facing that direction, rather than by a pre-mapped physical antenna. Therefore, the present invention achieves seamless and equal-gain coverage in any direction by decoupling the logical beam from the physical antenna, providing a stable communication link for command UAVs and mission UAVs.

[0067] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A beamforming method for decoupling a logical beam from a physical antenna, characterized in that: include: Step S1, installing a cylindrical antenna array on the command UAV, and the command UAV estimates the channel state information of the cylindrical antenna array according to the uplink detection signal transmitted by the mission UAV; The cylindrical array antenna array is composed of M columns of antennas, and the channel state information of the cylindrical array antenna array is stored in a matrix H; Step S2, calculating the signal power of each column of antennas in the cylindrical array antenna array according to the channel state information of the cylindrical array antenna array; Step S3, selecting the best N columns of adjacent antennas from the M columns of antennas, and extracting the channel state information corresponding to the selected N columns of adjacent antennas; The step S3 comprises: Step S31, find the antenna column with the largest signal power, and obtain the number i corresponding to the antenna column with the largest signal power max ; Step S32, set N=i max , selecting N-1 columns of antennas adjacent to the column of antennas with the largest signal power to form the optimal N columns of adjacent antennas; Step S33, obtaining an index set corresponding to the N columns of adjacent antennas, and extracting channel state information corresponding to the N columns of adjacent antennas; The step S32 comprises: Step S321, determine whether N is an odd number or an even number, if it is an odd number, proceed to step S322; if it is an even number, proceed to step S323; Step S322, selecting n antenna columns on the left and right sides of the antenna column with the largest signal power, where n=(N-1) / 2; Step S323, select the antenna on the left of the column with the largest signal power Column antenna, and the N-1-n1 column antenna on the right; among them, Indicates that the variable is rounded down; Step S4, acquiring a transmission signal according to the channel state information corresponding to the N columns of adjacent antennas, and the command UAV transmitting the transmission signal from the cylindrical array antenna array to the task UAV; The step S4 comprises: Step S41: Channel state information H corresponding to the N columns of adjacent antennas N Perform singular value decomposition to obtain the channel state information H corresponding to N columns of adjacent antennas N The eigenvector v corresponding to the maximum eigenvalue in kmax ; Step S42, set the shaping vector w=v kmax , weight the data symbol s to be transmitted using the assignment vector w to obtain the transmitted signal x; The channel state information corresponding to the N columns of adjacent antennas is subjected to singular value decomposition according to the following formula: subject to: [λ k ,v k ]=SVD(H N ), k=1,2,...,N, In the formula, SVD represents the matrix H N Perform singular value decomposition to obtain the matrix H N Each eigenvalue and corresponding eigenvector in ; λ k Denotes the matrix H N The kth eigenvalue in k Represents the eigenvector corresponding to the kth eigenvalue.

2. The beamforming method for decoupling logical beams from physical antennas according to claim 1, characterized in that: In step S2, the signal power p of each column of antennas i Calculate according to the following formula: p i =||H(:,i)|| 2 ,i=1,2,...,M; Where H(:,i) represents the i-th column of the matrix H, corresponding to the i-th column antenna in the cylindrical array antenna array.

3. The beamforming method for decoupling logical beams from physical antennas according to claim 1, characterized in that: The channel state information corresponding to the N columns of adjacent antennas is extracted according to the following formula: H N =H(:,S), Where S = {...,i max -1,i max ,i max +1,...}, H(:,S) represents the N columns of the matrix H.

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