Studies On Signal Detection Algorithms For MIMO Communication System

Multiple Input Multiple Output ( MIMO ) is a great breakthrough in wireless communication system in recent years. It can greatly improve the system capacity and performance without increasing power and bandwidth and is regarded as one of the key techniques for next generation communication systems. MIMO technique can enhance the system capacity and performance but also increases the complexity of detecting signals at the receiver. So signal detection is a key research issue in MIMO technique.This thesis proposes several improved detection algorithms based on related research works in MIMO signal detection technique and gives simulation tests and performance analysis.In the paper, we study the QR Chase detection algorithm and give its limits. In this paper two improved methods are proposed. The intents and purposes of them are to suppress error propagation and hence enhance the SER performance. Simulations results show that the SER performances of the two improved algorithms are improved greatly with reasonable increase of computational complexity.In the next, sphere decoding algorithm is studied and an improved method is given. It first uses QR decomposition detection algorithm to get an initial detection result, then decides whether the result is reliable or not under a reliability assessment. If it is judged to be reliable, we take it as the final result. If not, a proper initial radius can be obtained from the result and we use sphere decoding algorithm to get the final result. Simulation results show that the proposed algorithm can achieve or nearly achieve the same error performance as sphere decoding algorithm but has much lower computational complexity.Experiments are presented in the paper and simulation results and performance are analyzed.In the end, we give concluding remarks of the thesis and point out the next step of work in the future.