Joint channel estimation and signal detection for uplink MC-CDMA systems over time-varying multipath channels

In this paper, a recursive approach for joint channel estimation and signal detection is proposed for the uplink MC-CDMA system over time-varying multipath fading channels. Compared to the conventional channel estimation scheme for time-varying channels which generally requires pilot signals for every symbol, the proposed approach has the advantage of reducing these overhead bits and hence increasing the spectral efficiency. Taking advantage of the powerful processing capability of the base station, parallel interference cancellation (PIC) technique is exploited to cancel the multiple access interference (MAI) and enhance the system performance. Furthermore, a simple but effective method is proposed to prevent the possible error propagation. Space diversity (multiple receiver antennas) and time diversity (channel coding) can also be employed to suppress error propagation and improve system performance. Simulation results demonstrate that the proposed scheme is robust in multiuser scenarios for moderate signal to noise ratio (SNR) levels.