Enhanced Hybrid OMP Channel Estimation Algorithm for SC-IFDMA System in ISC

The presence of multi-path and Doppler effects of ionospheric scatter channel (ISC) leads to severe dual-selective fading, affecting channel estimation performance. To achieve reliable data transmission under ISC, a sparse channel estimate algorithm based on orthogonal matching tracking (OMP) for single carrier interleaved frequency division multiple access (SC-IFDMA) systems is proposed, called as enhanced hybrid OMP (EH-OMP). The EH-OMP integrates the linear minimum mean square error (LMMSE) of the OMP framework and incorporates a discrete Fourier transform (DFT) noise reduction algorithm. Simulation results show that the proposed algorithm outperforms the conventional OMP estimation algorithm. The transmission performance of the EH-OMP algorithm improves by about 1.8 dB when the bit error rate (BER) is 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>. The normalized mean square error (NMSE) of the EH-OMP algorithm is reduced by approximately 86% compared to the OMP at the low signal-to-noise ratio (SNR).