Underwater acoustic signal separation based on prior estimation of the channel impulse response

An underwater acoustic signals separation method based on prior information about the channel impulse response (IR) is presented. Using a sound speed profile measured in a real world environment, the IR of the ocean is estimated with normal mode theory and the ray tracing method. This propagation medium is characterized by a long duration finite IR composed alternatively of several intervals with null coefficients and peaks of non-zero amplitude that express the multi-path propagation. The channel IR characteristics are used as a prior knowledge to select intervals expected to contain non-zero coefficients to be adapted for separation filters estimation. Hence, the number of samples of filters to be adapted is highly reduced. The algorithm proposed by Yellin and Weinstein (1994) is used to successfully achieve the separation of two independent 16-QAM signals mixed in a realistic shallow water environment