Multiuser detection for frequency-hopped spread spectrum systems with BFSK modulation

This paper proposes new multiuser detectors for frequency-hopped spread spectrum multiple-access (FH-SSMA) based on binary frequency shift keying (BFSK) modulation and channelized frequency hopping. With knowledge of hopping sequences and envelopes of active users, the proposed scheme is a sub-optimal detector under maximum likelihood test. Diversity combining is employed as an anti-multiple-access interference technique which improves the performance significantly. In slow frequency-hopped systems, we demonstrate that the proposed multiuser detector combined with diversity is robust to multiple-access interference. In fast frequency-hopped systems with heavy load of multiple-access, the detector can afford more simultaneous users than the multiuser detector with M-ary frequency shift keying (MFSK) modulation.