Channel Tracking and Signal Detection for MC-CDMA in a Time-Varying Environment

In this paper, a joint channel estimation and multiuser detection method is presented for uplink multicarrier code-division multiple access systems in time-varying environments. Unlike the conventional channel-tracking schemes, which generally need to insert pilot signals in every orthogonal frequency-division multiplexing symbol, the proposed approach requires only one pilot symbol at the beginning of each data frame. Based on the fact that the channel coefficients of two successive symbols are highly correlated, subsequent channel tracking and signal detection are recursively carried out. A major feature of the proposed approach is that it enables robust error propagation control and is capable of effectively detecting and tracking abrupt channel changes. Simulation examples demonstrate the robustness of the proposed algorithms.