Pilot-Based Reception of OFDM with Index Modulation in Block Fading Channel

Abstract

Bit error probability (BEP) for uncoded orthogonal frequency division multiplexing with index modulation (OFDM-IM) transmitted over a channel with Rayleigh block fading is considered with account for imperfect channel state information (CSI) obtained from pilot signals. It has been shown that the distributed allocation of the subcarriers of the OFDM-IM subblocks provides a power gain of about 8 dB, but does not produce the diversity effect, and also that a time-frequency resource equivalent to one OFDM-IM subblock is sufficient for pilot signal allocation. Power losses due to imperfect CSI estimation are approximately 0.5 dB for concentrated allocation of subblocks and 1.2 dB for distributed allocation. Proposed analytical BEP formula is based on the maximum-correlation pairs of OFDM-IM subblocks augmented by pilot signal, it slightly exceeds BEP obtained by simulations.