An improved channel estimation scheme using polynomial-fitting and its weighted extension for an MC-CDMA/TDD uplink system with pre-equalization [mobile radio]

This paper deals with uplink channel estimation at a mobile transmitter for an MC-CDMA/TDD uplink system with pre-equalization. We present an enhanced version of a polynomial-fitting and extension (PF&E) scheme, which uses the idea of weighted extension. The scheme first approximates channel state information (CSI) estimates during some downlink slot interval to a polynomial of degree 2 in the least-squares sense, and then obtains the consecutive uplink CSI estimates by extending the approximated downlink CSI polynomial to the uplink slot interval, but with some temporal weighting corresponding to the maximum Doppler frequency. We perform computer simulations to analyze the overall bit error rate (BER) of the system under consideration, when the proposed scheme is used for uplink channel estimation. Extensive simulations show that the proposed scheme outperforms the PF&E scheme in terms of the overall BER under all the conditions considered.