Comparison of FH-MA communications using OFDM and DS-MA systems for wideband radio access

This paper investigates on the combination of OFDM with SFH as possible solution for a wideband radio multiple-access system. The OFDM component, with noncoherent DPSK demodulation, combats the multipath interference which may severely limit the system performance at high data rates, whereas the SHF portion provides multiaccess capability. The proposed system takes advantage of all the inherent benefits of the FH access, namely: the “near far” resistance and the possibility to employ side information for error and erasure decoding. The system has been compared with pure DS that, in its turn, exploits inherent predetection diversity. The obtained results show that, with appropriate channel coding, OFDM/FH can be considered a viable access scheme for high data rate applications. It is also shown that the proposed system can definitely outperform DS, provided that the OFDM component´s efficiency be properly optimized