A Two-dimensional Strategy of Adaptive Modulation and Coding for Underwater Acoustic Communication Systems

Underwater acoustic (UWA) channels are nearly the harshest wireless channels in nature, due to the severe characteristics of the oceanic environment, namely fast spatially and temporally variations. Therefore, considering that one modulation and coding scheme (MCS) is generally optimized for a specific channel condition, it will underperform when the channel statistics change. In this paper, we focus on the adaptive modulation and coding (AMC) technology and propose a two-dimensional (two-D) strategy of AMC for underwater acoustic communications (UAC). This strategy uses the joint function of SNR and the time-delay spread as the switching metric for different MCSs. From our simulation results, such a two-D approach has superior performance than the method with a fixed MCS and the widely used SNR based AMC algorithm in terms of reliability and system efficiency.