Survey and analysis of underwater acoustic channels for coherent communication in the medium-frequency band

A comprehensive set of acoustic communication data is analyzed using a complete receiver algorithm which includes a Doppler pre-processor, equalizer configuration algorithm and the decision feedback equalizer (DFE). The signal used for the tests is 1250 symbol per second QPSK (2500 bps) transmitted at a carrier of 2.25 kHz. Source-receiver ranges of up to 44 km were achieved at this data rate. The test environments include the New England Continental Shelf (less than 200 m), the shelf break (200-1200 m) and deep water (2500 m). In each environment the impulse response, the ambiguity function and the performance level of the receiver are presented. The link was very reliable to the maximum test range of 44 km on the shelf and to 20 km at the shelf break. In deep water the performance was good at less than 10 km and also at 35-44 km.