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Unformatted text preview: Exploring the Energy-Latency Trade-off for Broadcasts in Energy-Saving Sensor Networks * Matthew J. Miller Cigdem Sengul Indranil Gupta Department of Computer Science University of Illinois at Urbana-Champaign firstname.lastname@example.org email@example.com firstname.lastname@example.org Abstract Networking protocols for multi-hop wireless sensor networks (WSNs) are required to simultaneously min- imize resource usage as well as optimize performance metrics such as latency and reliability. This paper ex- plores the energy-latency-reliability trade-off for broad- cast in multi-hop WSNs, by presenting a new proto- col called PBBF (Probability-Based Broadcast Forward- ing). PBBF works at the MAC layer and can be inte- grated into any sleep scheduling protocol. For a given application-defined level of reliability for broadcasts, the energy required and latency obtained are found to be in- versely related to each other. Our analysis and simu- lation study quantify this relationship at the reliabil- ity boundary, as well as performance numbers to be expected from a deployment. PBBF essentially offers a WSN application designer considerable flexibility in choice of desired operation points. 1 Introduction Sensor nodes are inherently resource constrained. For example, an off-the-shelf Mote  has a lifetime of a few weeks (using a pair of standard AA batteries), short communication range distances, a 4 MHz proces- sor, a few KBs of SRAM, and a few MBs of Flash RAM. Offering better reliability and performance to a sensor network application (e.g., tracking, environmental ob- servation) leads to greater usage and depletion of these resources. To support a wide variety of future appli- cations, sensor networking technologies (hardware and software) will be required to provide enough flexibil- * This research was supported in part by NSF grant ITR- 0427089 and a NDSEG fellowship. Also affiliated with the Coordinated Science Laboratory. ity for a designer to choose the appropriate operation point on the resource-performance spectrum. In this paper, we focus on the broadcast prob- lem. Broadcast is useful to applications for dissemi- nating sensor data, instructions, and code updates. We study a probabilistic approach to exploring a resource- performance trade-off for broadcast communication. Assuming an energy-conserving sensor network, our goal is to design a broadcast protocol that allows a range of operating points from which an application designer can choose. To this end, we propose PBBF (Probability-Based Broadcast Forwarding), which is a MAC-layer approach and can be integrated into any sleep scheduling protocol. While some previous stud- ies of probabilistic broadcast in wireless networks work outside the MAC protocol , PBBF protocol works with the MAC protocol. We do not propose a new MAC protocol in this paper, but rather discuss a generic broadcasting protocol that can be built into any MAC layer with an appropriate sleep scheduling strategy....
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- Spring '08
- Computer Science