An investigation of coded OFDM and OFDM-CDMA waveforms utilizing different modulation schemes on HF multipath/fading channels

Orthogonal frequency division multiplexing-code division multiple access (OFDM-CDMA) is a technique that has been used to improve the robustness of OFDM. For uncoded waveforms, OFDM-CDMA has been shown to offer some significant performance advantages over OFDM on multipath/fading channels (Nieto, 2004). A recent paper (Nieto, 2005) reported that this performance advantage was greatly reduced for coded and interleaved waveforms. However, the results presented were only for 2-ary phase shift keying (2-PSK) modulation. This paper extends this research by investigating the performance of coded OFDM and coded OFDM-CDMA waveforms utilizing higher-order modulation schemes on various HF multipath/fading channels.