Abstract:

In order to exploit the sparsity inherent in underwater acoustic channel, and improve the channel estimation accuracy as well as the bit error rate of a cyclic prefixed single carrier block transmission system, a new sparse channel estimation scheme based on compressed sensing is proposed. The new method uses a pilot sequence with unit energy to construct frequency domain measurement matrix that satisfies restricted isometry property, and recovers sparse channel impulse response of the underwater acoustic channel from limited number of observation measurements by using Dantzig selector. Computer simulations based on real lake channel profile shows that the new method can significantly improve the channel estimation accuracy, the proposed compressed sensing based channel estimation method can outperform the traditional frequency domain least square method by about 5 dB when using frequency domain minimum mean square error detection method at the same training sequence length.

Key words: underwater communications, compressed sensing, sparse channel estimation, single carrier block transmission