CN-122026965-A - Channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method and system

CN122026965ACN 122026965 ACN122026965 ACN 122026965ACN-122026965-A

Abstract

The invention discloses a channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method and a system, wherein the method comprises the steps of constructing a Fisher information matrix based on channel parameter vectors based on a received signal model of a large-scale MIMO low-orbit satellite communication system under a pilot multiplexing condition; the method comprises the steps of extracting spatial features based on a Fisher information matrix, constructing a feature matrix which is a symmetric matrix and used for quantifying parameter estimation correlation among different user terminals, determining element values in the feature matrix according to an autocorrelation matrix and a cross-correlation matrix in the Fisher information matrix, reducing dimensions of the feature matrix to generate a channel map, and carrying out pilot frequency scheduling by utilizing relative spatial positions among users in the channel map based on the channel map so as to inhibit pilot frequency interference caused by pilot frequency multiplexing. The invention can effectively improve the channel estimation precision and the frequency spectrum efficiency of the low-orbit satellite large-scale MIMO system under the pilot frequency multiplexing scene.

Inventors

YOU LI
WANG YUANSHUO
ZHOU HUIBIN
GAO XIQI

Assignees

东南大学

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (10)

1. The channel map assisted large-scale MIMO low-orbit satellite communication pilot frequency scheduling method is characterized by comprising the following steps of: Constructing a Fisher information matrix based on channel parameter vectors based on a received signal model of a large-scale MIMO low-orbit satellite communication system under the pilot frequency multiplexing condition, wherein the channel parameter vectors comprise the arrival angle of a user terminal and channel gain information; Extracting spatial features based on the Fisher information matrix, constructing a feature matrix, wherein the feature matrix is a symmetric matrix and is used for quantifying parameter estimation correlation among different user terminals, and determining element values in the feature matrix according to an autocorrelation matrix and a cross correlation matrix in the Fisher information matrix; Performing dimension reduction on the feature matrix to generate a channel map; And carrying out pilot frequency scheduling by utilizing the relative spatial positions among users in the channel spectrum based on the channel spectrum so as to inhibit pilot frequency interference caused by pilot frequency multiplexing.
2. The channel map aided massive MIMO low-orbit satellite communication pilot scheduling method of claim 1, wherein the fischer information matrix is expressed as: ; Wherein the method comprises the steps of A set of users is represented and, Indicating the number of users, Representing the assumption that all users use the same first Fisher information matrix, autocorrelation matrix under pilot The elements in (a) are expressed as: ; Wherein the method comprises the steps of , Represent the first Complex channel gain for individual user terminals, Is that Is used for the real and imaginary parts of (a), And Representing array response vectors, respectively For angle of arrival And Is used for the purpose of determining the derivative of (c), And The number of subcarriers and the number of OFDM symbols, , And The number of elements of the satellite antenna array along the x-axis and the y-axis respectively, Is the power of the noise and, And Respectively represent the first Channel gain average power and rice coefficient of individual users 、 And Representing the transpose, complex conjugate and conjugate transpose operations respectively, Representing the real part; the absolute value is represented by a value of, Representing imaginary units; Cross correlation matrix The elements in (a) are expressed as: 。
3. The channel map aided massive MIMO low-orbit satellite communication pilot scheduling method of claim 1, wherein said channel parameter vector comprises a user terminal transmit signal on the satellite antenna array side And The angle of arrival of the direction, and the real and imaginary parts of the complex channel gain of the direct path.
4. The channel map aided massive MIMO low-orbit satellite communication pilot scheduling method of claim 1, wherein the feature matrix Is defined as Determining the element values in the feature matrix according to the autocorrelation matrix and the cross correlation matrix in the Fisher information matrix to be expressed as follows: ; Wherein the method comprises the steps of 、 Respectively the first Individual user and the first The same first user The autocorrelation matrix under the individual pilots is used, Is the first Individual user and the first The same first user The cross-correlation matrix under the individual pilots, The vectorization of the matrix is represented, Representing a binary norm.
5. The channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method of claim 1, wherein the feature matrix is reduced in dimension using a popular optimization algorithm.
6. The channel map aided large-scale MIMO low-orbit satellite communication pilot scheduling method of claim 1, wherein pilot scheduling is performed using relative spatial positions between users in a channel map, reducing correlation between users sharing pilots, equivalent to maximizing distance between pseudo-coordinates of users sharing pilots in the channel map.
7. The channel map assisted massive MIMO low-orbit satellite communication pilot scheduling method according to claim 1, wherein the pilot scheduling using the relative spatial positions between users in the channel map comprises: Initializing pilot frequency distribution, wherein a first user is selected as a central node, and a first pilot frequency sequence is distributed to the first user; iterative allocation, including searching a plurality of users closest to the users to which pilot frequencies are not allocated in the map for the users to which the pilot frequencies are currently allocated, and allocating a group of orthogonal pilot frequencies for the users; Updating the center node and iteration, including selecting the user farthest from the existing center node from all the users allocated with the pilot frequency as a new center node, repeating the iterative allocation step until all the users are allocated with the pilot frequency so as to maximize the average space distance in the internal spectrum of the user group sharing the same pilot frequency, thereby minimizing the intra-group interference.
8. A channel map assisted massive MIMO low-orbit satellite communication pilot scheduling system for implementing a channel map assisted massive MIMO low-orbit satellite communication pilot scheduling method according to any one of claims 1-7, comprising: the system comprises a Fisher information matrix construction module, a Fisher information matrix construction module and a channel parameter vector, wherein the Fisher information matrix construction module is used for constructing a Fisher information matrix based on a channel parameter vector based on a received signal model under the pilot frequency multiplexing condition, and the channel parameter vector comprises an arrival angle of a user terminal and channel gain information; The characteristic matrix construction module is used for extracting spatial characteristics based on the Fisher information matrix, constructing a characteristic matrix, wherein the characteristic matrix is a symmetrical matrix and is used for quantifying parameter estimation correlation among different user terminals, and determining element values in the characteristic matrix according to an autocorrelation matrix and a cross correlation matrix in the Fisher information matrix; the channel map generation module is used for reducing the dimension of the feature matrix and generating a channel map; And the pilot scheduling module is used for performing pilot scheduling by utilizing the relative spatial positions among the users in the channel map based on the channel map so as to inhibit pilot interference caused by pilot multiplexing.
9. A computer system comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the computer program when executed by the processor performs the steps of the channel map assisted massive MIMO low-orbit satellite communication pilot scheduling method according to any one of claims 1-7.
10. A computer program product comprising a computer program, characterized in that the computer program when executed by a processor implements the steps of the channel map assisted massive MIMO low-orbit satellite communication pilot scheduling method according to any one of claims 1-7.

Description

Channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method and system Technical Field The invention belongs to the technical field of wireless communication, and relates to a pilot scheduling method and a pilot scheduling system for large-scale MIMO-OFDM low-orbit satellite communication. Background In the air-sky-land-sea integrated network architecture for the sixth generation mobile communication, the low-orbit satellite communication system becomes a core component part of the air-sky-land-sea integrated network architecture, so that the global coverage capability, the broadband service accessibility and the emergency communication guarantee level can be obviously improved. It is expected that in the near future, the low orbit satellite will provide services for tens of thousands of user terminals by improving the communication reliability and reducing the transmission delay, so as to effectively make up for the gap of communication requirements in areas with insufficient coverage of the ground network or remote geography. To greatly improve the spectral efficiency and capacity of the system, large-scale MIMO output technology is introduced into low-orbit satellite communication systems to support future global, high-rate, low-latency communication services. In a wireless communication system, a pilot signal is a basis for realizing channel estimation, and a receiver acquires channel state information by means of a known pilot sequence, so that key processes such as coherent detection, precoding, interference coordination and the like are completed. In a large-scale MIMO system, accurate channel estimation is important to fully exert multi-antenna space dimension gain and realize high frequency spectrum efficiency. However, in a large-scale MIMO low-orbit satellite communication system, if orthogonal pilots are allocated to each user, the pilot overhead will increase linearly with the number of users, so that the limited time-frequency resources are severely squeezed, and it is difficult to support massive user access. Thus, the actual system must perform pilot multiplexing, i.e. multiple users share the same pilot sequence. The multiplexing mechanism can introduce inter-user interference, which results in reduced channel estimation performance and thus affects overall transmission reliability. When a pilot scheduling algorithm based on a Minimum Mean Square Error (MMSE) criterion in conventional massive MIMO is applied to a low-orbit satellite communication system, an inversion operation on a massive matrix is inevitably involved, so that the calculation complexity is in direct proportion to the cube of the number of base station antennas, and real-time communication of satellites cannot be satisfied. Disclosure of Invention The invention aims to provide a channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method and system, design a low-complexity pilot scheduling mechanism, ensure estimation accuracy and meet satellite communication real-time requirements, thereby effectively supporting large-scale deployment and efficient operation of the system. In order to achieve the purpose of the invention, the channel map assisted large-scale MIMO low-orbit satellite communication pilot scheduling method provided by the invention comprises the following steps: Constructing a Fisher information matrix based on channel parameter vectors based on a received signal model of a large-scale MIMO low-orbit satellite communication system under the pilot frequency multiplexing condition, wherein the channel parameter vectors comprise the arrival angle of a user terminal and channel gain information; Extracting spatial features based on the Fisher information matrix, constructing a feature matrix, wherein the feature matrix is a symmetric matrix and is used for quantifying parameter estimation correlation among different user terminals, and determining element values in the feature matrix according to an autocorrelation matrix and a cross correlation matrix in the Fisher information matrix; Performing dimension reduction on the feature matrix to generate a channel map; And carrying out pilot frequency scheduling by utilizing the relative spatial positions among users in the channel spectrum based on the channel spectrum so as to inhibit pilot frequency interference caused by pilot frequency multiplexing. Further, the fischer information matrix is expressed as: Wherein the method comprises the steps of A set of users is represented and,Indicating the number of users,Representing the assumption that all users use the same firstFisher information matrix, autocorrelation matrix under pilotThe elements in (a) are expressed as: Wherein the method comprises the steps of ,Represent the firstComplex channel gain for individual user terminals,Is thatIs used for the real and imaginary parts of (a),AndRepresenting array response vectors, respectivelyFor angle