| Abstract: | While multi-hop networks consisting of 100s or 1000s of inexpensive embedded sensors are emerging as a means of mining data from the environment, inadequate network lifetime remains a major impediment to real-world deployment. This paper describes several applications deployed throughout our building that monitor conference room occupancy and environmental statistics and provide access to room reservation status. Because it is often infeasible to locate sensors and display devices near power outlets, we designed two protocols that allow energy conservation in a large class of sensor network applications. The first protocol, Relay Organization (ReOrg), is a topology control protocol which systematically shifts the network’s routing burden to energy-rich nodes, exploiting heterogeneity. The second protocol, Relay Synchronization (ReSync), is a MAC protocol that extends network lifetime by allowing nodes to sleep most of the time, yet wake to receive packets. When combined, ReOrg and ReSync lower the duty cycle of the nodes, extending network lifetime. To our knowledge, this research provides the first experimental testbed evaluation of energy-aware topology control integrated with energy-saving synchronization. Using a 54-node testbed, we demonstrate an 82–92% reduction in energy consumption, depending on traffic load. By rotating the burden of routing, our protocols can extend network lifetime by 5–10 times. Finally, we demonstrate that a small number of wall-powered nodes can significantly improve the lifetime of a battery-powered network.W. Steven Conner is a Wireless Network Architect in the Communications Technology Lab, Intel Research and Development. He currently leads a team developing self-configuring wireless mesh networking technology and is an active participant in IEEE 802.11 standards development. His current research interests include wireless mesh networking, sensor networks, and network self-configuration protocols. He received B.S. and M.S. degrees from the University of Arizona.Jasmeet Chhabra received B.E. (1996) and M.S. (1999) degrees from University of Delhi and University of Maryland, College Park, respectively. Since 1999 he has been a researcher in the Communications Technology Lab, Intel Research and Development. His current research interests include sensor networks, ubiquitous computing, mesh networks and security.Mark Yarvis received B.S. (1991), M.S. (1998), and Ph.D. (2001) degrees in computer science from the University of California, Los Angeles. Since 2001, he has been a Senior Researcher in the Communications Technology Lab, Intel Research and Development. He is currently the principle investigator of the Intel Research Heterogeneous Sensor Networking project. His research interests include heterogeneous systems, sensor networks, and pervasive and mobile computing. He is a member of IEEE and ACM. WWW: Lakshman Krishnamurthy manages the radio networks initiative in the Intel Corporate Technology Group and is also the principal investigator of the EcoSense wireless sensor network Strategic Research Project. He leads research efforts into new wireless mesh protocols and techniques to provide ease of use and improve performance of wireless networks. As part of the EcoSense project, Lakshman is driving wireless sensing into Intel fabs by piloting a preventative maintenance application. Currently, he also serves on the program committees of the ACM SenSyS and IEEE SECOM conferences. Lakshman received a Ph.D in computer science from the University of Kentucky and a BE in instrumentation technology from the University of Mysore, India.This revised version was published online in August 2005 with a corrected cover date. |
