LDPC Decoding With Low Complexity for OFDM Index Modulation

In this paper, the posterior probabilities of the low-density parity check (LDPC) coded bits are derived for the orthogonal frequency division multiplexing index modulation (OFDM-IM) system to reduce the implementation complexity of LDPC decoding without performance loss. Specifically, the complexity of LDPC decoding is reduced by decomposing the posterior probability of the coded bit into multiple likelihood probabilities, each of which is obtained for each subcarrier of the corresponding OFDM-IM subblock. The results of the complexity analysis indicate that the proposed approach significantly reduces the implementation complexity of LDPC decoding for OFDM-IM compared to the conventional approach. Furthermore, the simulation results confirm that the proposed approach provides the same bit error rate performance as the conventional approach.