The Study Of Space-time Coding In Mimo System

In the future mobile communication system, the communication requirements will expand from simple voice business to high rate multimedia business including video, image. There is an increasing capacity demand for high speed wireless data access system with continue increasing of the amount of subscribers. It may not be efficient or even practicable to expand the channel capacity by purely increasing the bandwidth and the transmit power due to the limitation of the spectrum resources. Multiple-input multiple-output (MIMO) technology is a significant breakthrough in the area of wireless communication. MIMO systems use more channels supplied by multiple antennas (antenna array) at the transmitter and the receiver. All the signals transmitted from different antennas use the same frequency bandwidth, so it can greatly increase the capacity and frequency efficiency of communication system. MIMO technology is known as the future trend of wireless communication technology. Space-time coding (STC) technology is a coding technology to increase the spectrum efficiency based on the MIMO systems. STC introduces the correlations in both time and space domains when signals are transmitted by different antennas, which can greatly enhance the data transmission rate and improve the performance without bandwidth expansion or transmit power augment. Thus the space-time coding is intended to provide a new solution to the problem of limited bandwidth.The main points are as follows:1. Introduce the model of the MIMO system and the channel capacity of MIMO system, as well as diversity technique2. Introduce the model of space-time coding technique and the design criterion over the flat fading channel. Study three kinds of coding schemes of space-time code: space-time block code, threaded layered space-time code, layered block space-time code.3. Review the diagonal algebraic space-time block code in detail. Introduce the thought of layer space-time coding, we present a high rate full diversity space-time block code scheme called it as layered block space-time code, and analyze the performance through the computer simulation.4. Considering the complexity of decoding algorithm for the layered block space-time code, we present an improvement scheme and the simplified decoding algorithm. In the end we compare the performance of different scheme through computer simulation.