Multi‐user underwater acoustic communication using binary phase‐coded hyperbolic frequency‐modulated signals

Multi-user communication traditionally uses either code division multiple access (CDMA) or time-division schemes. The chirp signals resilience to multipath and the Doppler effect makes it suitable for underwater acoustic communication. This paper presents a binary phase-coded hyperbolic frequency-modulated (BPC-HFM) multi-user proposed scheme has advantage of both linear signal, which is immune offset, while PN sequence encoded in such manner that waveform possesses phase shift 0 180 depending upon results unique orthogonal every user. As result, helps reduce interference; addition, time-reversal mirror technique used enhance performance system high environment due virtue hydro-acoustic channel. Furthermore, relatively simple matched filter-based receiver. To substantiate robustness waveforms three types channels using different numbers users are chosen simulation bit error rate (BER) calculated. compared signal conventional Direct spread spectrum CDMA.