Design of a QPSK-CDMA acoustic communication system for multiple underwater vehicles

This paper designs an underwater acoustic communication system based on QPSK-CDMA (Quaternary Phase Shift Keying-Code Division Multiple Access) for multiple underwater vehicles. Through this system, multiple underwater vehicles can communicate with the console on the water surface simultaneously without interference. The communication system is composed of channel encoding and decoding, spread spectrum modulation and demodulation, RF (Radio Frequency) modulation, Rake Receiver and synchronization. As an important factor that affects the quality of acoustic communication, the underwater channel is also taken into account. The simulation results indicate that it is feasible to use this system to accomplish underwater communication reliably due to the small BER (Bit Error Ratio).