Channel Estimation for Multi-layer Block Transmissions over Underwater Acoustic Channels

Accurate channel estimation in underwater acoustic communications is critical to achieving high rate signaling. This paper addresses the problem of channel estimation for underwater acoustic channels by exploiting a recently proposed parametric representation model for wideband channels. Using multiple co-located frequency bands for layered data transmission, as proposed by the parametric representation, allows for multiple observations of the channel impulse response each at a different sampling rate. Directly combining the measurements from the different frequency bands degrades the channel estimation accuracy, due to the relationship between the measurements and the use of sparse recovery techniques with a mismatched basis. By pre-processing the data to optimize the sensing matrix for this problem, we show that the channel estimation error can be reduced significantly when compared to recovery techniques without pre-processing.