Subblock design aided orthogonal frequency division multiplexing with all index modulation using search algorithm

Abstract

AbstractOrthogonal frequency division multiplexing with index modulation (OFDM‐IM) harvests significantly better error performance compared with OFDM due to its design of the index bits. However, the structure of conventional OFDM‐IM scheme does not fully focus on the enhancement of the bit error rate (BER) performance. In the proposed subblock design aided OFDM with all index modulation (SD‐OFDM‐AIM), unconditional pairwise error probability (UPEP) is taken as the objective function to select the subblock realizations with low error rates, leading to the BER performance enhancement. Noticing that UPEP uses the channel state information (CSI), we fully discuss the calculation of CSI and analyze the effect on subblock design under imperfect channel evaluation. Moreover, inspired by sphere decoding method, we propose the low complexity decoder to remove the high burden of computational complexity in former OFDM with all index modulation (OFDM‐AIM) after the reconstruction of the look‐up table. The simulation results demonstrate its superiority at BER performance compared with the index modulated OFDM schemes and OFDM‐AIM.