An Improved Energy Efficient Cross-layer Scheme in Underwater Wireless Sensor Networks

Cross-layer approaches are widely applied in the development of underwater wireless sensor networks (UWSNs) to tackle limited network resources. However, most existing research addresses convex optimization problems consisting of cross-layer parameters based on cross-layer interaction, without delving into the specific implementation process of the cross-layer mechanism. In this paper, we propose a systematic cross-layer information interaction mechanism between the physical layer and the media access control (MAC) layer to optimize the techniques and protocols. Then, based on this mechanism, we combine adaptive techniques with orthogonal frequency division multiplexing (OFDM) systems, focusing on the adaptive modulation, power control, and bit allocation algorithms adopting two threshold division methods to improve energy efficiency. In addition, the role of the improved TDMA protocol and enhanced S-FAMA protocol in the cross-layer mechanism is briefly elaborated. Finally, we integrate the techniques and protocols mentioned above and perform simulations. The results verify the rationality and validity of the cross-layer scheme in terms of energy efficiency.