Phase shift-based pilot frequency design method in large-scale MIMO system

Abstract

The present invention relates to a phase shift-based pilot frequency design method in a large-scale MIMO system. The method comprises the following steps of 1 establishing an optimization problem by taking the minimum interference sum in a system as a target, and designing a phase shift value of each cell in the system; 2 adopting a discrete particle swarm search algorithm to solve the optimization problem in the step 1 to obtain the phase shift value of each cell; 3 on the basis of the phase shift values obtained in the step 2, adopting a tabu search-based pilot frequency distribution algorithm to obtain a pilot frequency design scheme capable of reducing the pilot frequency pollution. According to the present invention, by establishing and solving the optimization problem of the minimum interference in the system, the correlation of the pilot frequency matrixes between two cells of large mutual interference is weak, and the correlation of the pilot frequency matrixes between two cells of small mutual interference is strong, thereby reducing the pilot frequency pollution. On the basis of the pilot frequency phase shift, by adopting a pilot frequency distribution scheme of low complexity and a tabu search-based pilot frequency distribution method, the channel estimation precision and the frequency spectrum efficiency of the system are improved.

Description

technical field [0001] The invention belongs to the field of uplink channel estimation in a massive MIMO system in wireless communication, relates to pilot sequence generation and pilot scheduling in a massive MIMO system, and is specifically a phase-shift-based pilot in a massive MIMO system design method. Background technique [0002] In order to improve the utilization of limited spectrum resources and meet people's increasing wireless communication needs, massive MIMO (Large Scale MIMO or Massive MIMO) has become one of the key technologies for the new generation of wireless communication systems. It serves dozens of users using the same time-frequency resources at the same time through a base station equipped with hundreds of antennas. Studies have shown that as the number of base station antennas increases, noise and irrelevant inter-cell interference will be negligible; and simple signal processing methods such as Maximum Ratio Combining (Maximum Ratio Combining, MRC...

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Problems solved by technology

However, this document treats all cells and all users in the cell equally when designing the phase offset value of each cell, and does not take large-scale information into account, and this document conducts a pilot length when designing the phase shift However, the obtained phase shift is not optimal, so the improvement of system performance is not particularly ideal

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