A Delay-Time / Code Division Multi-Access In A Frequency-selective Channel

Abstract Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion has been attracting much attention to improve the bit error rate (BER) performance of DS-CDMA by obtaining the frequency diversity gain. In the uplink case, however, since MMSE-FDE cannot transform the channel into a frequency-flat channel, multi-access interference (MAI) (or called multi-user interference (MUI)) appears. In this paper, we propose a delay-time/code division multi-access (DT/CDMA) which shifts the signal spectrum in the delay-time domain so that different users’ spectrums are not overlap while obtaining the frequency diversity gain. In this paper, we present the principle of DT/CDMA and evaluate the achievable BER performance by computer simulation. Keyword Multi-access, frequency-selective, delay-time, frequency-domain equalization