Polar-Coded OFDM With Index Modulation

In this paper, we apply polar codes to a modified version of OFDM systems with index modulation which is called OFDM with in-phase/quadrature index modulation (OFDM-I/Q-IM). We provide general design guidelines for the proposed polar-coded OFDM-I/Q-IM systems. In the proposed system, at the transmitter, we employ a random frozen bits appending scheme which not only makes the polar code compatible with OFDM-I/Q-IM but also improves the bit error rate (BER) performance of the system. Furthermore, at the receiver, it is shown that the a posteriori information for each index provided by the index detector is essential for the iterative decoding of polar codes by the belief propagation (BP) algorithm. Simulation results show that the proposed polar-coded OFDM-I/Q-IM system outperforms its OFDM counterpart in terms of BER performance.