Overlap MMSE-Frequency-domain Equalization for Multi-carrier Signal Transmissions

Recently, multi-carrier code division multiple access (MC-CDMA) has been attracting much attention for the next generation mobile communication systems. The insertion of the guard interval (GI) is necessary to avoid the inter-block interference (IBI), resulting in the transmission efficiency loss. In this paper, an overlap frequency-domain equalization (overlap FDE) technique, which requires no GI insertion, is presented for MC-CDMA signal transmission. The received MC-CDMA signal is divided into a sequence of M-sample signal blocks, where M is smaller than the number Nc of MC-CDMA subcarriers and then each block is equalized by using the overlap MMSE-FDE with Nc-sample FFT. Setting the block size M to be smaller than the FFT block size Nc, the IBI can be sufficiently reduced. The achievable BER performance with overlap MMSE-FDE in a frequencyselective Rayleigh fading channel is evaluated by computer simulation.