Performance Evaluation of OFDM Index Modulation with LDPC Code

In this paper, performance of orthogonal frequency division multiplexing (OFDM) with index modulation (IM) based schemes is evaluated. We consider the well known OFDM-IM, where partial subcarriers are activated and the corresponding indices convey extra information, and its variant multiple-mode OFDM-IM (MM-OFDM-IM) which provides better spectral efficiency (SE) and uncoded bit error rate (BER) by activating all subcarriers and using distinguishable constellations. Although uncoded performance has been extensively discussed for these techniques, performance with channel codes involved lacks of evaluation and discussion. Therefore, we present both uncoded and coded BER performance with new radio (NR) low density parity check (LDPC) code in this paper, where LDPC codes with different code rates are employed. Simulation results show that OFDM-IM based scheme with LDPC code outperforms the conventional OFDM with LDPC code only within a limited code rate range, although its uncoded performance offers large gains at high SNR.