Performance of Concatenated Optimized Irregular LDPC Code with Alamouti Coded MIMO-OFDM Systems

-Multiple input multiple output (MIMO) communication systems along with orthogonal frequency division multiplexing (OFDM) have a great potential for future 4G broadband wireless communications. Recently, low density parity check codes (LDPC) achieves good error correcting performance and capacity near Shannon’s limit. In this paper, we considered the performance analysis of serially concatenated regular and irregular LDPC codes with Alamouti space time block coded (STBC) and space frequency block coded (SFBC) MIMO-OFDM systems for high data rate wireless transmission. Currently, most of the research related to this area is concentrated on the impact of increase in code rate and diversity of the system but not on increase in coding gain. In this paper, we analyzed the impact of increasing coding gain. Performance analysis and design optimization is carried out using density evolution (DE) tool with mixture of Gaussian approximations over Rayleigh independent and identically distributed (i.i.d) channels Key-Words: MIMO-OFDM, Alamouti codes, Density Evolution (DE), LDPC codes, Maximum a Posteriori (MAP), Maximum Likelihood (ML) detection.