An Energy Efficiency Evaluation for Sensor Nodes with Multiple Processors, Radios and Sensors

This paper constructs a model for studying the energy efficiency of sensor node architectures featuring a pair of low-end, low-power processor and radio and a pair of high-end, energy efficient processor and radio. Such nodes can have a highly dynamic range of operation ranging from the collection of simple temperature measurements or motion detection all the way up to sophisticated signal processing of sensor data. Our model explores the energy efficiency tradeoffs related to the decision of which processor and which radio should be used for each task. For this we derive a general Semi-Markov Decision process model for maximizing the asymptotic lifetime of two alternate designs, one with dynamic and one with static interconnect. The resulting models are validated with simulation and are applied to the reported measurements from an existing platform with two radios and two processors. Our results show how to quantify the gains of such design with respect to the power consumption properties of each component. Furthermore, based on our power budget calculation, we conclude that the deisgn of reconfigurable interconnect between multiple processors and radios would result in efficiency gains despite the energy overhead such device may incur.