Iterative Multicarrier Detector and LDPC Decoder for OFDM Systems

-In this paper, we propose iterative soft-input soft-output (SISO) multi-carrier detection (inter-carrier interference cancellation) and LDPC decoding of the OFDM system in the mobile channel. The proposed SISO multi-carrier detection and sum-product decoding of the LDPC-coded OFDM system can achieve better error rate performance than previous SISO multi-carrier detection and BCJR decoding of convolutional coded (CC)-OFDM systems in mobile channels. The simulation results show that the second iteration improves the performance significantly and the gain of the third iteration is less. The advantage of LDPC over CC is more significant when the codeword is longer. With channel estimation errors, the proposed scheme degrades by 0.5 dB for the 3 rd iteration. In addition, the proposed LDPC-OFDM scheme has lower computational complexity than the CC-OFDM one. Key-Words:inter-carrier interference, turbo principle, OFDM, LDPC, computational complexity