An FHMA acoustic communication system for multiple underwater robots

This paper proposes an underwater acoustic communication system based on tamed spread spectrum and FHMA (Frequency Hopping Multiple Access) for multiple underwater robots. In this system, multiple underwater robots can communicate with the console on the water surface simultaneously successfully. The communication system is composed of tamed spread spectrum modulation and demodulation, frequency hopping modulation and demodulation with synchronization function, 4FSK modulation and demodulation and Rake Receiver. As an important factor that affects the quality of underwater acoustic communication, underwater channel is also taken into account. The simulation results indicate that it is feasible to use this system to accomplish underwater communication reliably for multiple users due to the low BER (Bit Error Ratio).