Studies on multilevel frequency-shift keying/frequency-hopping spread-spectrum multiple-access (MFSK/FH-SSMA) wireless systems are mostly assumed to support only one type of media. Since a flexible support of multimedia services is expected in future, the use of conventional fixed-length FH patterns alone cannot serve these multi-rate, multi-media wireless systems. In this paper, a family of double-length, fixed-weight generalized prime hopping patterns, well suited for wireless systems with double-media services, is reviewed. The performances of the prime hopping patterns and conventional random hopping patterns in MFSK/FH-SSMA wireless systems are analyzed and compared for one type of media first and extended to two types. Our results show that the proposed scheme performs better than the conventional one with random hopping patterns.

There has been much interest in the application of frequency hopping-spread spectrum multiple access (FH-SSMA) to wireless systems because of its frequency diversity and resistance to the near-far problem. In FH-SSMA systems, cochannel interference (CCI) is the dominant factor limiting the user capacity. Various techniques used to resolve the CCI problem have been extensively investigated. We propose several multiuser detection schemes based on canceling CCI to increase user capacity in a multilevel frequency shift keying (MFSK)/FH-SSMA system. The performance of systems with the proposed interference cancellers over a Rayleigh fading channel are analyzed and compared with those of the conventional and other interference cancellers. Our results show that the proposed schemes have the best performance in both nonfading and fading channels.