PROJECT TITLE :

An Efficient Receiver Structure for Sweep-Spread-Carrier Underwater Acoustic Links

ABSTRACT:

In this paper, we present an improved receiver design for sweep-spread-carrier modulation, a spread-spectrum technique proposed to effectively contrast the effects of time dispersion over multipath propagation channels in underwater acoustic wireless links. The proposed structure is capable of cashing in on the energy received from all propagation methods rather than solely from the strongest path, as envisaged within the pioneering paper introducing this modulation technique. A hardware version of the modem was implemented in the laboratory and its behavior was assessed and compared, using commonplace propagation models, to that exhibited by the ancient single-path-primarily based theme in terms of bit error rate. Results are presented showing that gains of a few decibels can be achieved in signal-to-noise-and-interference ratio. Issues relevant to carrier/image synchronization, channel estimation, and sensitivity to Doppler distortion also are addressed.