1Telecommunications and Digital Signal Processing Laboratory, University Djillali Liabes of Sidi Bel Abbes 22000, Algeria.
2I.E.M.N. Dept. O.A.E, (U.M.R. 8520, C.N.R.S.) ENSIMEV, Université de Valenciennes et du Hainaut Cambresis le Mont Houy 59313 France.
3laboratoire LAMIH UMR C.N.R.S 8530, Université de Valenciennes et du Hainaut Cambresis le Mont Houy 59313 France.
This paper examines the performance of a multicarrier CDMA system over multipath fading channel. Due to the dispersive nature of the mobile communications channels, Multi-Carrier Code Division Multiple Access (MCCDMA) signals will be affected by Inter Channel Interference (ICI), Inter Symbol Interference (ISI) and Multiple Access Interference (MAI), due to the loss of subcarrier orthogonality. To solve the ISI problem, a cyclic extension was introduced to the transmitted symbols, known as guard time, but its introduction results into loss of spectral efficiency. In this context, we consider the use of a Frequency-Time minimum mean square error Equalizer (FTE) to compensate for the corresponding loss in performance, and compare the resulting MC-CDMA systems with the use of guard time. The effect of system parameters such as output Signal-to Noise Ratio (SNR), number of sub-carriers, delay spread, is investigated by simulation, from which we show that MC-CDMA/FTE provides better performance than guard time technique.
Guard time, MMSE equalizer, Multi-carrier CDMA, Multipath fading channels
