Coded Index Modulation with Block Markov Superposition Transmission for Highly Mobile OFDM Systems

This paper is concerned with the coded orthogonal frequency division multiplexing (OFDM) with index modulation (IM) for highly mobile wireless communication based on block Markov superposition transmission (BMST). In the OFDM-IM scheme, the information bits are not only mapped into the conventional two-dimensional signal points but also into the indices of the subcarriers. For the coded IM system, we choose BMST codes, which can be easily designed for any given code rate with a predictable performance lower bound. In this paper, linear minimum mean square error (LMMSE) equalization is used to mitigate the intercarrier interference (ICI) and exchange messages with the soft demapper. An iterative sliding-window decoding algorithm is also presented to the BMST decoder. To reduce the complexity, we ignore the interference between different groups of IM system. Numerical results show that the BMST-IM system performs well over time-varying frequency-selective channels and outperforms BMST-OFDM scheme at the same spectral efficiency.