The Design And Performance Optimization Of LDPC-Coded MIMO OFDM System

In recent years one kind of multi-carrier modulation (MCM) technique called orthogonal frequency division multiplexing (OFDM) is widely studied because it can effectively resolve many problems. In this paper we concentrated on the performance analysis and design optimization of LDPC-Coded MIMO OFDM systems (low-density parity check coded multiple-input multiple-output orthogonal frequency division multiplexing systems) for high data rate wireless transmission. The main research and results are the following:(1) The OFDM system analysis and simulation. Based oh detailed research of the mobile channel, we discuss the key techniques of OFDM system, describe a DFT-based OFDM system, model it in a frequency selective fading channel, and simulate it in computer.(2) The encoding and decoding algorithm of LDPC Codes. We discuss the newest LDPC encoding techniques including its technique background, characteristics, and the encoding and decoding algorithm. A LDPC-Coded OFDM system is simulated by computer at last.(3) The key techniques of MIMO system. We discuss the key techniques of the MIMO system, and attempt to combine the OFDM technique with the MIMO technique to form a new system——MIMO OFDM system.(4) The performance analysis and design optimization of LDPC-Coded MIMO OFDM systems. We attempt to apply the LDCP codes to the MIMO OFDM system. The optimization is done for various LDPC-Coded MIMO OFDM system configurations, which include a different number of antennas, different channel models, and different demodulation schemes. The optimized performance is compared with the corresponding channel. At last, we give some advices about the optimization of LDPC-Coded MIMO OFDM system.