Reverse link performance of a coded OFDM/SFH-CDMA transmission scheme

Multicarrier CDMA has been proposed as a promising technique for data transmission at high data rates, because it allows simpler receivers than single carrier DS-CDMA systems using the RAKE technique. While the design of the forward link does not seem difficult (as many papers have demonstrated), the same conclusion is not valid for the reverse link. Here we present a new architecture based on OFDM and slow frequency hopping code division multiple access (OFDM/SFH-CDMA) which seems to be suitable for the reverse link where users transmit asynchronously. For its simplicity of implementation we consider incoherent DQPSK as the modulation scheme. We find that the joint use of channel coding, sub-carrier interleaving and antenna diversity is capable of significantly reducing the error rate (three orders of magnitude at SNR/bit=25 dB). In particular, the use of antenna diversity appears to be indispensable because it provides the required significant reduction of the error rate.