Differential modulated OFDM system for HF communications

Abstract

Signals in HF radio channels are suffered from the effect of delay spread, time-varying interference and additive Gaussian noise. The performances of two differential modulation methods FDDD and TDDD for OFDM system are analyzed in this paper. By analysis and simulations, the relationship of the subcarrier bandwidth and BER is demonstrated, which shows that the selection of optimal subcarrier bandwidth contributes largely to the performance of HF communications.