Pilot-Based Channel Estimation in Time-Variant MC-DS-CDMA Systems

We propose and analyze a low-complexity pilot-based channel estimator for a multi-carrier direct-sequence code-division multiple access (MC-DS-CDMA) system in a time-variant (TV) channel. The TV channel is estimated individually for every flat-fading sub-carrier, assuming no inter-carrier interference. We use Fourier basis expansion model (FBEM) to fit the practical TV channel. With the knowledge of spread sequence of the desired user, we can obtain a matrix containing the Fourier bases coefficients and the corresponding transmitted data symbols, which are the very first and the very last data symbols of the examined transmitted data serial. Inserting pilot at those two positions, we can get the Fourier bases coefficients and recovered the TV channel. Simulation results show that this scheme is promising