System on high-speed underwater acoustic communication with multi-carrier

High-speed underwater acoustic communication with multi-carrier is used for real-time transmission with high data rate and low bit error rate, and it plays an important role in AUV. OFDM (orthogonal frequency division multiplexing) is an attractive multi-carrier communication method around the world. According to the requirements of high-speed underwater acoustic communication with multi-carrier, a system is designed for OFDM communication from hardware and software. The multiple processors with 4 ADSP-TS101s makes up of cluster/data flow associated multiprocessing parallel processing structure as the operation kernel. The receiver composed of multi-channel synchronous sample module and the transmitter with FIFO (first in first out) are designed and implemented. And the FPGA is used to realize the logical control and data package. The methods of interrupts of DMA (direct memory access) and half-full are used to realize data transmission with high speed at background. And the signal synthesis method, DDS (direct digital synthesis), is adopted to realize producing OFDM signal in real time. Through the experiments in a lake, the results show that the system had good stability and real-time processing capability, it can complete the OFDM signal transmission and receiving with high speed.