Studies On Signal Detection Algorithms For MIMO Communication System

Multiple Input Multiple Output (MIMO) is the key technology for the next generation of wireless communications.It makes full use of spatial multiplexing and transmit diversity techniques to improve the system capacity and performance without increasing power and band width. In MIMO technique, signal detection is a key issue, and is also the focus of this study.This thesis in-depth study the sphere decoding based on related research works in MIMO signal detection technique and analysis the initial radius of sphere decoding algorithm. In this paper,we propose an algorithm to determine the initial radius without a large number of preprocessing, through comparativly analysis that the method for selection of initial radius in practical application is derived.In this paper, we study the sphere decoding algorithm and give its limits. Then we propose three improved methods. The intents and purposes of them are to enhance the bit error rate (BER) performance and have a very large computational complexity loss. The three methods are as follows:It proposes a layered sort adaptive sphere decoding (LSA-SD) algorithm. This method improves the traditional sphere decoding process of selection of the candidate node and the methods of the radius zoom in and out. The improved algorithm compares with the traditional sphere decoding which has a very low computional complexity, at the same time the performance is no loss.The adaptive choosing better radius sphere decoding algorithm and the based reliability assessment algorithm both improve the LSA-SD algorithm. They solve the problem of the LSA-SD having a large computional complexity because of the small initial radius. The two methods also greatly reduce the computional complexity, at the same time the performance loss is small.In this article, a large number of simulation experiments for different detection algorithms are carried out and the results are analyzed. In the end, we give concluding remarks of the thesis and point out the next step of work in the future.