Design of Underwater Acoustic Modems through High Performance DSPs

Abstract

In this paper, we present an acoustic modem hardware design through the use of a low power, high performance digital signal processor (DSP). The modem uses either MFSK or MPSK modulation methods for data transmission. The floating-point DSP, TMS320C6478, is used to transmit the modulated signal, perform demodulation, and support the network protocol. Several algorithms including Doppler shift correction, adaptive equalizer, and TURBO decoder are fully implemented in the DSP. A low-power, high performance Xilinx FPGA, XC6SLX45, is also used to handle the peripherals. When in the low power mode for the MFSK scheme, the acoustic modem has a power consumption of 0.8 watt. When performing the MPSK scheme, the total power consumption of the modem is 1.5 watt. The designed modems are currently used in our underwater acoustic network.