Estimating node lifetime in interference environments

For commercial Wireless Sensor Network (WSNs) deployments it is necessary to estimate the network lifetime. It must be possible before network deployment to determine how long a network maintains operational before maintenance is required and batteries have to be replaced. Unfortunately, node lifetime is very dependent on the radio environment in which the node is operated. As we will demonstrate in this paper the node lifetime in a very busy radio environment can be up to 11 times shorter than in a quiet environment. WSNs employ duty-cycled communication protocols where receivers periodically sample the channel to determine if it has to remain active to receive a message. Radio interference triggers the receive mechanism causing an unnecessary wake-up which leads to an increase in a node´s energy consumption. In this paper we present a method for estimating node energy consumption in a target radio environment. We describe how to capture the essential characteristics of the radio environment and how to use this information to predict node lifetime. We demonstrate the usability of the proposed method using the well known WSN communication protocol ContikiMAC. Our evaluation comprising real-world scenarios shows that the proposed method is able to accurately predict node lifetime.