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Sparse channel estimation for filtered multitone in underwater communications

Underwater acoustic (UWA) communications are major tools for wireless data transmission in underwater environment. In recent years, multicarrier modulation has become one of the dominating methods in mitigating the time-delay and Doppler doubly-spread UWA acoustic channel. In this paper, one of the multicarrier modulations called filtered multitone (FMT) is proposed for UWA communications which splits the transmission bandwidth into several subbands with negligible inter-carrier interference (ICI). Considering the UWA channel model, a sparse structure that parameterizing the amplitude variation and delay variation of each path with polynomial approximation is investigated. Based on this structure, the channel estimation problem is transformed into estimating the parameter sets, e.g., delay spread and Doppler sc for each path, which characterize the UWA channel. After the construction of the estimation templates, orthogonal matching pursuits (OMP) algorithm which belongs to compressive sensing is adopt in this work for sparse channel estimation. The performance of the FMT sparse channel estimation for UWA communications is evaluated via numerical simulations.