Parametric Channel Estimation by Exploiting Hopping Pilots in Uplink OFDMA

In this paper, a parametric channel estimation algorithm applicable to uplinks of orthogonal frequency division multiple access (OFDMA) systems whose subcarriers are pseudo-randomly allocated is proposed. By exploiting pilot hopping, estimation of signal parameters via rotational invariance technique (ESPRIT) is employed to estimate the path delays of the sparse multipath fading channel. From the delay information, a channel interpolator utilizing global pilots, which can be irregular distributed, is derived to estimate the channel state information on the desired tones. Moreover, a simple method of estimating the time correlation of the channel taps is introduced and integrated in the proposed algorithm. Simulation results demonstrate that the proposed algorithm outperforms the local linear channel interpolator within a wide range of SNR's and Doppler's.