SE PhD Prospectus Defense of Wei Si

2:00 pm on Monday, May 5, 2014
4:00 pm on Monday, May 5, 2014
15 Saint Mary's Street, Rm 105
TITLE: Intra-car Wireless Data Collection Protocols ABSTRACT: Traditionally, in-vehicle sensors have been communicating with a central receiver through wires. With the increasing number of sensors inside cars, the large amount of wires brings about issues such as fuel inefficiency and difficulty of car design and maintenance. These limitations have created impetus to replace wired links with wireless links, thus leading to the deployment of intra-car wireless sensor networks (WSNs). Experimental results have shown, however, that wireless channels of intra-car WSNs are noisy and dynamic. In this thesis, we propose to tackle the challenge of designing and evaluating data collection protocols for intra-car WSNs that can work reliably and efficiently under such dynamic channel conditions. Our work leverages two existing data collection protocols, the Collection Tree Protocol (CTP) and the Backpressure Collection Protocol (BCP). As part of our preliminary results, we uncover a surprising behavior in which, under certain dynamic channel conditions, the average packet delay of BCP is high at low traffic load and decreases as the load in the network increases. We propose and analyze a queueing-theoretic model based on matrix-geometric methods and probability generating functions to shed light into the observed phenomenon. As a solution, we propose a new protocol, called replication-based LIFO-backpressure (RBL). Initial analytical and simulation results indicate that RBL dramatically reduces the delay of BCP at low load, while maintaining high throughput performance at high load. In the second part of the proposal, we present TeaCP, a prototype Toolkit for the evaluation and analysis of Collection Protocols in both simulation and experimental environments. TeaCP evaluates a wide range of standard performance metrics, such as reliability, throughput, and latency. TeaCP further allows visualization of packet routes and the topology evolution of a network, under both static and dynamic conditions, even in the face of transient disconnections. Through simulation of an intra-car WSN and real lab experiments, we demonstrate the functionality of TeaCP for comparing the performance of different data collection protocols. COMMITTEE: Advisor: David Starobinski, SE/ECE; Ari Trachtenberg, SE/ECE; Ioannis Paschalidis, SE/ECE; Thomas D. Little, SE/ECE