Performance analysis of DWT based OFDM with index modulation under channel estimation error

Inspired by the high spectral efficiency improvement of the Spatial Modulation (SM), Orthogonal Frequency Division Multiplexing with Index Modulation (OFDM-IM) was recently proposed and expected to be one of the key technologies of 5G systems. This novel transmission technique incorporates the index of active subcarriers to convey additional information. Similar to conventional OFDM, channel estimation error is considered as a dominant performance degrading cause of OFDM-IM system. This paper deals with robust OFDM-IM system implementation under practical conditions. For this purpose, Discrete Wavelet Transform (DWT) based OFDM-IM is announced to improve the performance of the conventional OFDM-IM affected by non ideal channel estimation. To this purpose, DWT based OFDM-IM performance in terms of Bit Error Rate (BER) is compared to the original OFDM-IM based on Fast Fourier Transform (FFT) in the presence of channel estimation error. Simulation results are provided to prove the performance enhancement of our proposed system over Rayleigh fading channel.