A new scheme for MC-CDMA systems in the presence of imperfections

The combination of code division multiple access (CDMA) and multi-carrier (MC) modulation has been proposed for high rate wireless communications. The main idea is to transmit the high data rate stream on a number of parallel lower rate channels. The long symbol duration associated with each subcarrier makes the system more susceptible to various imperfections, such as frequency offset, phase noise and fast fading, that destroy the orthogonality between the subcarriers and degrade performance. In this paper, we propose a novel and simple receiver structure to address the effects of imperfections. The proposed receiver fully compensates for the frequency offset and phase noise effects and, unlike existing designs, exploits temporal channel variations to attain a higher level of diversity, thereby improving system performance over that under slow fading.