Low-Complexity Soft-Decision Detection of Coded OFDM With Index Modulation

In this paper, the low-complexity soft-decision detectors of the orthogonal frequency division multiplexing with index modulation (OFDM-IM) in both single- and two-level coded modulation systems are studied. In the single-level coded OFDM-IM, the bitwise Markov chain Monte Carlo (b-MCMC) detector can overcome the drawback of the conventional symbolwise MCMC detector that the signal vectors obtained by Gibbs sampling are trapped in the activation pattern (AP) of the initial vector. By integrating with the randomized step further to alleviate the stalling problem, the randomized b-MCMC detector is proposed. In the two-level coded OFDM-IM, the framework of iterative multistage decoding (IMSD) with two component detectors for AP and symbol information, respectively, is employed. To reduce the complexity of IMSD, the efficient processing of the multiplicative interference in the component detectors is proposed. Finally, the effectiveness of the proposed detectors is verified by computer simulations.