Ph.D. Dissertation Defense - Bin Tong

Date: 19 Aug, 2009
Time: 2:00 PM
Location: 223 Atanasoff Hall
Topic: Mobility-assisted energy replenishment for sensor networks
Major Professor(s): Wensheng Zhang


Abstract:

Abstract:
Over the past decade, sensor networks have consistently been a focus of computer research community. One of the fundamental research problems of sensor networks is the energy scarcity problem. The energy scarcity problem is defined as how to support sensor networks to work towards an expected period of time given scarce energy supply in sensor nodes. A large number of schemes have been proposed to address this problem. These schemes, however, have one or more the following drawbacks: i) energy cannot be replenished to the network, and thus the network lifetime is bounded by the amount of energy preloaded to sensor nodes; ii) the ways of replenishing energy to sensor nodes are not practical and reliable, and thus cannot support normal operations of the network; and iii) sensor nodes drained of energy are left in the sensing field, and thus cause pollution to the environment.

Fully addressing this problem requires energy to be continually replenished into sensor nodes in a reliable, efficient, and environment-friendly way. In this dissertation, we investigate two approaches for energy replenishment of sensor networks: (i) Node Reclamation and Replacement Approach: Sensor nodes with low or no energy are reclaimed periodically, and are replaced with fully charged ones; and (ii) Wireless Recharging Approach: Sensor nodes are periodically recharged with energy transmitted from wireless chargers over radio. Both approaches exploit mobility in accomplishing energy replenishment. Specifically, one or more mobile agents, which could be human technicians or robots, travel around the network, and perform sensor reclamation and replacement or wireless recharging task. We propose an array of schemes that address different fundamental issues in realizing these approaches.

Extensive analysis and simulations have been conducted to verify the effectiveness and efficiency of our solutions.