Frequency hopped-chirp modulation (FH-CM) for multi-user signaling in multipath dispersive media

Chirp signals are categorized as spread-spectrum signals and have good advantages in interference rejection. The use of matched chirp modulation (MCM) for efficient digital signaling in dispersive communication channels has also been considered by El-Khamy et al. (1980, 1988). Chirp modulation has also been considered for multi-user applications. New forms of multi-user chirp modulation (M-CM) signals that are characterized by the same power as well as the same bandwidth have also been introduced previously by the authors. In this paper, we investigate the combination of frequency-hopping (FH) spread-spectrum techniques with M-CM to produce a multiple-access technique that is characterized by good performance in dispersive and fading propagation media. The considered frequency-hopped chirp modulation (FH-CM) is investigated in detail and its performance is shown to outperform that of M-CM.