Mutual interferences in a binary FH-FSK spread spectrum system for mobile radio

A binary frequency-hopped frequency shift keying (FHFSK) spread spectrum system for mobile radio communication as well as an address assignment scheme for such a system and an evaluation of error probabilities due to mutual interferences in binary FH-FSK in function of the number of simultaneous users are presented. In the absence of any form of synchronization between sequences, the system´s performance is not as good as frequency-hopped differential phase shift keying (FH-DPSK) for any decoding scheme; decoding with intermediate decisions on interval pairs (i, i + L/2) in a sequence of length L gives approximately the same performance as when using only the combiner circuit and maximum likelihood decoding. With synchronization between sequences at the chip level, however, the results show binary FH-FSK performance comparable to that of frequency-hopped multilevel frequency shift keying (FH-MFSK) and thus, substantially better than that of FH-DPSK.