Differential pattern time delay shift coding underwater acoustic communication using parametric array

Abstract

The long range and high data rate communication are two main targets of point to point underwater acoustic communication (PPUAC). In order to achieve the longer communication range, low frequency is the best choice. However, the data rate is limited by narrow available bandwidth at low frequency. So, the system band select must compromise between the data rate and communication range according to the application scenarios. Parametric array can achieve considerable bandwidth at the low frequency band with narrow beam pattern by nonlinear acoustics conversion. These characteristics meet the requirements of both data rate and communication range to a certain extent, and make the channel equalization more simple and effective. A PPUAC scheme based on differential pattern time delay shift coding using parametric array has been proposed. The system employs a 150 kHz primary frequency then get a 10 kHz secondary frequency wave. A proof test has been carried out under ice in SongHua River, HeiLongjiang Province, China. The error free communication was achieved in the trial. The communication scheme is expected to been used in underwater platform directional remote control and other scenarios.