The Research Of Space-Time Detection Algorithm For MIMO System

Multiple Input Multiple Output (MIMO) system is a great breakthrough in wireless communications, which can greatly increase the channel capacity and spectrum efficiency without occupying any more bandwidth. It is the key technology must be adopted by the new generation of the wireless communicaton system.This paper can be mainly summarized in to three aspects as follows:1. Firstly, the paper analyzes the system model of MIMO, derive the formulas of channel capacity for the slow flat Rayleigh fading channel, analyzes two improtant facts affected the system capacity, and then via the computer simulation we compare the channel capacity between the tranditonal wireless system and MIMO system. The theoretic formulas imply that MIMO system can make use of multipath fading in full of scatter enviorment and its channel capcacity is in proportion to the transmt or receive antenna.2. Paper mainly explains the basic principle of Bell Laboratory Layered Space-time (BLAST) architecture. As an efficient method to achieve the enormous channel capacity, the core of BLAST architecture is based on the Ordering Successive Interference Cancellation (OSIC) detection algorithm. Through"Interference Nulling"and"Interference Cancellation"operation and"Decision Feedback", this algorithm can accumulate signal diversity gain to improve its performance. But the original BLAST algorithm has a very high computational cost because of the nulling and cancellation step. On the other hand, the algorithm also needs an optimal detection ordering to restrain the effect of error propagation and improve the detection reliability. At the same time, when the number of transmit and receive antenna tend to be large; the orginal BLAST algorithm will become not stability. Therefore, the original BLAST algorithm is not suit for the system in the real world. Depending on in-depth analysis of existing Space-time detecting algorithm, we propose a double-directional BLAST detection algorithm base on MMSE criterion. It has good computational cost because of avoiding any inverse operation and optimal ordering. It also utilizes double-directional detection and diversity combine technology to migrate the error propagation, and then improve the BER performance.3. Finally, through the computer simulations, paper compares BER performance of various space-time detection algorithms for the slow flat Rayleigh fading MIMO...