Research On Antenna Selection In Distributed MIMO Communication System

Distributed MIMO(Multiple-Input Multiple-Output)technology is a combination of traditional point-to-point centralized MIMO technology(referred to as centralized MIMO technology)and distributed antenna technology.Compared to centralized MIMO technology,distributed MIMO technology can expand signal coverage and improve cell-edge user experience.Compared with distributed antenna technology,it can achieve greater system capacity.Therefore,distributed MIMO technology is considered as a very promising future communication technology.This paper has studied the antenna selection technology of distributed MIMO system,the specific research content is reflected in the following aspects:(1)The number of antennas in a distributed MIMO system is much larger than the number of antennas in a centralized MIMO system and a distributed antenna system.The existing antenna selection algorithm does not consider the distributed characteristics of a distributed MIMO system,if we directly use the existing antenna selection algorithm with excellent performance in the MIMO system,it will be difficult to exert the advantage of the algorithm because of the computational complexity brought by the increase of the antenna.This paper proposes an antenna selection algorithm for preselected port postselection antennas based on the distributed features of distributed MIMO systems.First,the antenna port unit is filtered according to the set threshold,and then antenna selection is performed in the selected antenna port.Taking into account the possible correlation between the antennas of the same antenna port unit,the correlation between the antennas will cause a certain degree of capacity loss,so the antenna selection is performed according to a norm-correlative criterion,and it is successively selected the antenna that contributes more to the system capacity by the iterative update optimization parameters.Compared with the classical algorithm,the simulation results show that the algorithm not only has lower computational complexity but also has system capacity similar to the exhaustive search method.Then,an antenna selection algorithm with increasing energy efficiency is used for each selected antenna port unit in each cell to obtain a set of transmission antennas with optimal energy efficiency in each cell,and a transmission antenna set based on energy efficiency optimization for a multi-cell distributed MIMO system is finally obtained.(2)Given that energy conservation is an important development direction of wirelesscommunication systems,this paper proposes an antenna selection algorithm based on energy efficiency optimization in multi-cell distributed MIMO systems.First,the antenna port unit is selected according to the correlation matrix and the large-scale channel information.This algorithm uses an antenna selection method that reduces the feedback overhead at the transmitter,and the transmitter only needs to obtain the channel correlation matrix and the channel large-scale information.In addition,the joint signal processing in the same cell is also considered,and signals of other cells are considered as interference signals.The simulation results show that the performance of this algorithm is close to the optimal algorithm.At the same time,the performance of the proposed algorithm is superior to the large-scale channel information algorithm.