Channel Estimation for Enhanced Subcarrier Index Modulation OFDM Using Zadoff-Chu Sequence Pilot in Nonlinear Channel

Orthogonal Frequency Division Multiplexing with Index Modulation (OFDM-IM) is a digital modulation scheme that conveys additional information bits by using the index of subcarriers. OFDM with enhanced subcarrier index modulation (OFDM-SIM) has been recently proposed to improve the bit error rate (BER) performance of multicarrier communication systems. It is challenging to estimate channel variation of the OFDM-SIM system in wireless communication systems for coherent detection at the receiver side. This paper proposes a new pilot data information Zadoff-Chu sequence for the channel estimation OFDM-SIM system. And OFDM-SIM channel estimation will be done by using the conventional OFDM-SIM symbol pilot and the proposed Zadoff-Chu sequence pilot in the multipath Rician fading channel. And evaluate the simulation results by using BER performance. BER results of channel estimation OFDM-SIM with proposed Zadoff-Chu sequence pilot decreased than BER results of channel estimation OFDM-SIM using conventional OFDM-SIM symbol pilot. And we evaluate the proposed Zadoff-Chu sequence channel estimation OFDM-SIM in a nonlinear multipath Rician fading channel. We can see that the proposed Zadoff-Chu sequence pilot outperformed than conventional OFDM-SIM symbol pilot in every input back off (IBO)=0 dB, -2dB, -4dB, and -6dB. Our proposed channel estimation method is evaluated by using computer simulation.