Underwater acoustic communications using M-ary chirp-DPSK modulation

Various spread spectrum techniques have been used to offer low data rate acoustic links. A new complex waveform named M-ary chirps (MCSS) for underwater acoustic communication without complicated signal processing, was presented and successfully tested in a lake by us in [1]. In order to increase the data rate, a novel modulation method combing MCSS, DPSK and time overlapping named MCSS-DPSK is proposed in this paper. Simulation results based on underwater channel model using lake test data show that Rake receiver with MCSS-DPSK have a robust performance in multi-path underwater acoustic channel. A water tank experiment was conducted to verify the performance of MCSS-DPSK, results showed that it was robust in multi-path channel.