Rahul C. Shah

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This paper presents and analyzes an architecture to collect sensor data in sparse sensor networks. Our approach exploits the p m n c e of mobile entities (called MULES) present in the environment. MULEs pick up data from the sensors when in close range, buffer it, and drop off the data to wired access points. This can lead to substantial power savin@ at the(More)
The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. In this paper we take the view that always using lowest energy paths may not be optimal from the point of view(More)
This paper presents and analyzes a three-tier architecture for collecting sensor data in sparse sensor networks. Our approach exploits the presence of mobile entities (called MULEs) present in the environment. When in close range, MULEs pick up data from the sensors, buffer it, and deliver it to wired access points. This can lead to substantial power(More)
Different opportunistic routing protocols have been proposed recently for routing in sensor networks. These protocols exploit the redundancy among nodes by using a node that is available for routing at the time of packet transmission. This mitigates the effect of varying channel conditions and duty cycling of nodes that make static selection of routes not(More)
One of the most compelling challenges of the next decade is the “last-meter” problem, extending the expanding data network into end-user data-collection and monitoring devices. PicoRadio supports the assembly of an ad hoc wireless network of selfcontained mesoscale, low-cost, low-energy sensor and monitor nodes. While technology advances have made it(More)
An ultra-low power access control scheme has been proposed for broadband wireless sensor networks. This is a distributed method, which does not require the existence of a central base station, eliminating the possibility of a single point failure. This access protocol combines the best of simple carrier sense multiple access (CSMA) and spread spectrum(More)
Determining the mode of transport of an individual is an important element of contextual information. In particular, we focus on differentiating between different forms of motorized transport such as car, bus, subway etc. Our approach uses location information and features derived from transit route information (schedule information, not real-time)(More)
In this paper, a detailed study of the performance of geographic routing protocols in the presence of localization errors is carried out. Both analytical and simulation results illustrate the major impact of localization errors on the protocol goodput and route discovery energy. The performance metrics observed were the packet delivery ratio and the power(More)
Proper frequency planning is essential to enablemultiple IEEE 802.15.4 networks to coexist in the samespace, otherwise the network performance can beadversely affected due to interference. While this maybe feasible for static networks, it is not really an optionfor mobile networks such as body area networks due tothe dynamic nature of these interactions.(More)