Characteristics of OFDM/CDMA System Using Frequency and Time Domain Spreading

This paper presents BER performances of OFDM/CDMA using combined frequency and time domain spreading (abbreviated as FT-CDMA). In the system, we employ a different frequency interleaver for each user and adaptive filters to suppress multiple access interference in an asynchronous multiple access system. In conventional MC-CDMA and MC-DS/CDMA systems, the improvement of BER performance can be obtained from only frequency or time domain however, in the FT-CDMA, it can be obtained from both domains. The performance are evaluated in a multi-path fading channel (a close 6-path model). As a result of computer simulations, it is shown BER performance of FT-CDMA is superior to that of the others in the channel