Implementation of an OFDM underwater acoustic communication system on an underwater vehicle with multiprocessor structure

Abstract

Orthogonal frequency division multiplexing (OFDM) can fully use the frequency band and transmit data at high speeds. The ADSP-TS101 is a high performance digital signal processor (DSP) with good properties that include parallel processing and a high speed. Aimed at the real-time processing requirement of the OFDM algorithm, an underwater acoustic communication system with real-time processing capability is carried out. The system is mainly composed of multiple ADSP-TS101s, a multi-channel synchronous sample module and a field programmable gate array (FPGA) chip. The multiprocessor structure is made up of a cluster/data flow associated multiprocessing parallel processing structure as the operation kernel, and a multi-channel synchronous sample module is designed to realize no phase warp among the multiple channels  data at the same time. The digital modulation/demodulation methods are applied to the OFDM algorithm. Through experiments in a lake, the results show that the system has good stability and real-time processing capability, thus satisfying the design requirements.