DEPLOYMENT OF A 27.5 KHZ LINK USING NON-COHERENT SPACE TIME BLOCK CODED FREQUENCY SHIFT KEYING

Abstract

The contents of this thesis explore the challenge of implementing a high-speed and reliable acoustic communication link in shallow water conditions and high flow environments, in which highly varying propagation conditions are induced. These characteristics are implemented in a software model to represent a realistic ocean environment for in-lab algorithm design. The process for designing a simple, non-coherent, multiple input-multiple output (MIMO) communication system combined with frequency shift keying (FSK) to achieve robust performances are discussed. Robustness is achieved through the implementation of a space time block code. The transmitter for a software defined acoustic modem is implemented. Two modes of operation are tested at sea: a high throughput coherent system relying on phase shift keying, as well as a low-throughput design relying on MIMO-FSK. The performance of the STBC in a real channel is evaluated and effect of the spatial correlation between the MIMO channels are discussed.