A Compensated EM-Based Channel Estimation for Orthogonal Wavelet Packet Modulation System

This paper proposes a novel iterative channel estimator for orthogonal wavelet packet modulation (OWPM) systems over frequency-selective fading channels. The channel estimation algorithm herein designed introduces linear interpolation to compensate the original value offered by expectation-maximization (EM) algorithm for iterative step. With the utilization of the coherence among both subcarriers and symbols, the performance is improved substantially. We conduct particular simulations with comparing the bit-error-rate (BER) obtained from traditional EM algorithm and our algorithm for QPSK/16QAM. Moreover, the convergence behavior of the two algorithms is also investigated through the simulations under frequency-selective multipath conditions. The results show that our method performs better than the conventional EM algorithm both in BER and convergence performances.