Research On Turbo Iterative Detection Method Of Space-Time Codes For MIMO System

The MIMO technology for wireless communications is an advanced technology which applies multiple antennas on both the transmitter and the receiver. It provides an optional key solution for high-capacity and high-speed air interface in future bottleneck problems of wireless communication. Space-Time Coding is a kind of channel coding method based on MIMO architecture which combines space diversity (antenna) and time diversity (time interval) together to achieve union diversity gain. It can acquire great capacity improvement compared to single antenna system and is regarded as the key technology for Next Generation High-Speed wireless communications.MIMO system, whose antenna works under same frequency, is a self-interference system, making interference unavoidable to every antenna. This causes the main problem for Space-Time Coding to be detection technique. Furthermore, the two main functions for MIMO are Diversity and Multiplexing. The tradeoff of them is an important problem for Space-Time Coding. In such aspects, Layered Space-Time Codes (BLAST) is a good method to solve both two problems above through Error-Control Coding and Layering technique and their detection performance can be greatly improved by Turbo-like detection methods. Hence, BLAST has great implement prospect in future wireless communications.This dissertation has made deep research in Turbo principle and Layered Space-Time Coding detection methods. The main four contributions are as following:1. The author proposes a new interleaving method based on research of Turbo Codes. The Interleaver leads an important role in Turbo Codes. By analyzing its optimization effects on distance spectrum, this paper proposed a new low-complexity method based on three-Dimensional (3-D) matrix. Through the distance separation and randomizing, the new method improves the BER performance of Turbo Codes compared with other conventional interleaving methods.2. The author proposes an iterative detection method for BLAST system. By studying of conventional detection methods for BLAST system, this paper applies a parallel iterative detection method, which uses soft information estimation and soft Interference-Cancellation processing to mitigate error propagation effect. Through few numbers of iteration this method can improve the detection performance greatly.