Sreekanth Yalamanchili’s Thesis Defense.
October 17, 2012
1:00pm – 3:00pm
Dr. Sirisha Medidi
Wireless sensor networks (WSNs) are event based systems that rely on the collective effort of several sensor nodes. When all nodes in an area sense an event and transmit that data, it causes sudden traffic bursts which are spatially-correlated and leads to network congestion. Congestion can cause an increase in the amount of data loss, energy consumption and delay in data transmission and hinder network performance. To improve performance of event driven applications, there arises a need for protocols which can reduce congestion and energy consumption. Existing protocols for sensing multiple events either handle congestion control or spatially-correlated contention, but not both, which can degrade network performance in terms of packet delivery ratio, latency, and energy consumption. Motivated primarily by the challenge to improve performance of event driven applications, we propose an energy efficient protocol to mitigate congestion which improves data delivery and reduces latency. This protocol mitigates congestion by dispersing network traffic using a forwarder selection mechanism that forces event reports from different nodes to disperse along different paths to the base station. Our protocol also reduces spatially-correlated contention by partitioning the sensors into different groups, so that, for each group, sensors in that group together cover the region of interest and scheduling these groups in such that only one group is active to transmit the data at any given time. We implemented our protocol using the NS2 simulator for evaluating its performance. Results show that our protocol has significant improvement in packet delivery ratio, latency and energy savings.