Time-Domain Spreading And Frequency-Domain Spreading for Delay-time/Code Division Multi-Access

The uplink (mobile-to-base) bit error rate (BER) performance is significantly degraded due to the multi-access interference (MAI). Recently, we have proposed a new hybrid multi-access technique, called delay-time/code division multiaccess (DT/CDMA). A different user is assigned a different cyclic time delay and/or spreading code. DT/CDMA can obtain the frequency diversity gain while suppressing the MAI. In the previous paper, time-domain spreading was considered. In this paper, we consider frequency-domain spreading and compare the achievable BER performances of DT/CDMA using time-domain spreading and frequency-domain spreading.