A Low-Complexity Orthogonal Matching Pursuit Algorithm Based on Multi-Scale Multi-Lag Underwater Acoustic Channels

This paper studies the estimation of parameter for wideband underwater acoustic (UWA) channel with multi-scale and multi-lag (MSML) characteristics, within the framework of the OFDM system. Based on the Orthogonal Matching Pursuit (OMP) reconstruction model, the high computational complexity issue caused by over-parameterized dictionaries during channel estimation is addressed. A low-complexity OMP algorithm based on independent stepwise search is proposed. This algorithm leverages the MSML characteristics of UW A channels to concentrates the computation cost waste problem of inner in critical regions, thereby solving the computational waste problem of the OMP algorithm, which requires repeated inner product calculations in each iteration. This provides a low-complexity, high-performance channel estimation solution for underwater OFDM communication.