The effect of network coexistence on the performance of wireless sensor networks

Abstract: With the coming growth in Internet of Things (IoT) applications, we can expect environ-ments with many independent networks operating in nearby locations. Wireless Sensor Networks (WSN), which have become popular during the last few years, are the main type of networks used in IoT. The IEEE 802.15.4 protocol designed for low-rate wireless personal area networks has been widely adopted for this kind of network. Together with ZigBee, this protocol is gaining increasing interest from the industry, as they are con-sidered a universal solution for low-cost, low-power, wireless connected monitoring and control devices. Internetwork interference issues in IEEE 802.15.4 networks can be a ma-jor problem because of the extensive use of wireless channels. In this thesis, an in-depth simulation study of the internetwork interferences is performed using Castalia, a widely used network simulator. We focus on the beacon collision problem, as it has been proved to be the main cause of performance degradation for coexisting networks. We carry out a prestudy of the main node simulation parameters to setup the different scenarios. Then, we evaluate how the overlap of the active periods and the location of the nodes affect the network performance. We continue with a network coexistence analysis to study the inter-action of two networks of two nodes and their performance regarding the beacon reception rate. We show that there are significantly different operation regions, depending on the network location. Following this, a probabilistic analysis is carried out in order to obtain an average beacon reception rate depending on the size of the area considered. Finally, we discuss available beacon collisions avoidance methods, taking into account the detailed simulation results. Our conclusions have theoretical and practical implications for the design of wireless sensor networks, and for the evaluation of beacon collisions avoidance schemes.