The Performance Searching Of QC-LDPC Coded MIMO-OFDM System

The goal of next generation wireless communication is to realize the mobile multimedia transmission with high quality, high speed, and to everywhere. As a combination of OFDM with space-time coding technique, MIMO-OFDM has recently received considerable attentions, which can not only effectively enhance the transmission rate and capacity of the wireless communication system but also effectively combat multi-path fading and interfere. Therefore, the application of MIMO-OFDM in wireless communication systems is remarkable.Low Density Parity Check (LDPC) codes are a good liner block codes, which perform at a rate extremely close to the Shannon capacity. Its error-correcting ability has tight connection with the construction way in encoder. QC-LDPC codes are characterized by the parity-check matrix which consists of small square blocks which are the zero matrix or circulate permutation matrices. It is an important branch of LDPC codes. Encoding of a quasi-cyclic (QC) LDPC code can be achieved with simple shift-registers, being prone to hardware realization.In this paper we introduce the basic theory of MIMO-OFDM system first. Second we present a new architect QC-LDPC code , combined with the MIMO-OFDM system. Simulation results show that performance of purposed system is better than that of tradition regular LDPC coded MIMO-OFDM system over frequency-selective channels at high code rate.