An improved channel estimation method using doubly reduced matching pursuit over fractional delay multipath channel

Owing to the inherent sparse channel feature in multi-carrier modulation systems, compressed sensing (CS)-based techniques have been used for channel estimation with less pilot subcarriers for orthogonal frequency division multiplexing (OFDM) systems. Because of a sparse multipath channel's characteristic of fractional delay, the channel measurement matrix that is generated by conventional time-domain sampling approaches cannot perfectly recover the channel impulse response (CIR), especially in the case of two adjacent paths that both have with non-negligible power. In this study, a fractional delay multipath channel model is used to simulate the wireless multipath channel. In addition, a time-domain oversampling based doubly reduced matching pursuit (DRMP) algorithm at the receiver is proposed to improve the estimation accuracy while reducing the computational complexity. Simulation results show that the proposed method can improve both the bit error rate (BER) performance and estimation time compared to conventional methods in an environment with fractional delay.