Low Complexity Joint Channel Estimation and Decoding for LDPC Coded MIMO-OFDM Systems

In this paper, a joint iterative channel estimation and Low-Density Parity-Check (LDPC) decoding algorithm based on factor graphs and the sum-product algorithm is proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems employing multiple transmit and receive antennas (MIMO). By modeling time-varying frequency-selective fading channels as Auto-Regressive (AR) processes and approximating messages as Gaussian pdf, this receiver algorithm is able to maintain a low complexity. Moreover, with the help of strong channel coding, pilot overhead can be significantly reduced.