An Energy Efficient Cross-Layer Design for Healthcare Monitoring Wireless Sensor Networks

In wireless sensor networks (WSN), the nodes have limited energy resource. So power conservation in individual node is of significant importance. In this paper we derive a cross-layer design method that combines adaptive modulation and coding (AMC) at the physical layer and two sleep modes according to monitoring type at the medium access layer (MAC) in healthcare monitoring WSN, judiciously to maximize spectral efficiency, and to minimize energy consumption, under prescribed error performance constraints. To achieve maximum spectral efficiency in the entire SNR (signal-to-noise ratio) range, we advise a combined transmission mode switching between convolutionally code and unconvolutionally code mode, based which we analyze the energy consumption of the system with multi mobile nodes and a sink node and verify that it is energy efficient to adopt AMC instead of single modulation at physical layer in healthcare monitoring WSN.