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Unformatted text preview: A Transmission Control Scheme for Media Access in Sensor Networks Alec Woo Department of EECS Computer Science Division University of California, Berkeley email@example.com David E. Culler Computer Science Division University of California, Berkeley and Intel XIS Lab firstname.lastname@example.org ABSTRACT We study the problem of media access control in the novel regime of sensor networks, where unique application behav- ior and tight constraints in computation power, storage, en- ergy resources, and radio technology have shaped this design space to be very different from that found in traditional mo- bile computing regime. Media access control in sensor net- works must not only be energy efficient but should also allow fair bandwidth allocation to the infrastructure for all nodes in a multihop network. We propose an adaptive rate control mechanism aiming to support these two goals and find that such a scheme is most effective in achieving our fairness goal while being energy efficient for both low and high duty cycle of network traffic. 1. INTRODUCTION Sensor networks are an important emerging area of mobile computing that presents novel wireless networking issues be- cause of their unusual application requirements, highly con- strained resources and functionality, small packet size, and deep multihop dynamic topologies. Although many high- level architectural and programming aspects of this area are still being resolved, the underlying media access con- trol (MAC) and transmission control protocols are critical enabling technology for many sensor network applications. These problems are well-studied for traditional computer networks, however, the different wireless technologies, appli- cation characteristics, and usage scenarios create a complex mix of issues that have led to the existence of many distinct solutions. It is natural to expect the low-level protocols to evolve again for this new era. Application behavior in sensor networks leads to very dif- ferent traffic characteristics from that found in conventional computer networks. The primary function of a sensor net- work application is to sample the environment for sensory information, such as temperature, and propagate this data back to the infrastructure, while perhaps performing some in-network processing, such as aggregation or compression. The network tends to operate as a collective structure, rather than supporting many independent point-to-point flows. Traf- fic tends to be variable and highly correlated. Over lengthy periods there may be little activity or traffic, but for short periods the traffic may be very intense. For example, when an abnormal event, such as a fire, is detected, many de- vices will initiate communication at once. Often, applica- tions will arrange periodic rendezvous so that data can be communicated over many hops while allowing nodes to turn off their radios for lengthy periods. Even in the simplest case, roughly periodic sampling of the sensor field yields correlated bursts, even when the duty cycle is low.correlated bursts, even when the duty cycle is low....
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This note was uploaded on 08/25/2011 for the course EEL 5937 taught by Professor Staff during the Spring '08 term at University of Central Florida.
- Spring '08