Network-Calculus-based Performance Analysis for Wireless Sensor Networks

Recently, wireless sensor network (WSN) has become a promising technology with a wide range of applications such as supply chain monitoring and environment surveillance. It is typically composed of multiple tiny devices equipped with limited sensing, computing and wireless communication capabilities. Design of such networks presents several technique challenges while dealing with various requirements and diverse constraints. Performance analysis techniques are required to provide insight on design parameters and system behaviors. Based on network calculus, we present a deterministic analysis method for evaluating the worst-case delay and buffer cost of sensor networks. To this end, three general traffic flow operators are proposed and their delay and buffer bounds are derived. These operators can be used in combination to model any complex traffic flowing scenarios. Furthermore, the method integrates a variable duty cycle to allow the sensor nodes to operate at low rates thus saving power. In an attempt to balance traffic load and improve resource utilization and performance, traffic splitting mechanisms are introduced for mesh sensor networks. Based on network calculus, the delay and buffer bounds are derived in non-splitting and splitting scenarios. In addition, analysis of traffic splitting mechanisms are extended to sensor networks with general topologies. To provide reliable data delivery in sensor networks, retransmission has been adopted as one of the most popular schemes. We propose an analytical method to evaluate the maximum data transmission delay and energy consumption of two types of retransmission schemes: hop-by-hop retransmission and end-to-end retransmission. We perform a case study of using sensor networks for a fresh food tracking system. Several experiments are carried out in the Omnet++ simulation environment. In order to validate the tightness of the two bounds obtained by the analysis method, the simulation results and analytical results are compared in the chain and mesh scenarios with various input traffic loads. From the results, we show that the analytic bounds are correct and tight. Therefore, network calculus is useful and accurate for performance analysis of wireless sensor network.