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A look at positioning aspects of future sensor networks. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such(More)
U ltra-wideband (UWB) radios have relative bandwidths larger than 20% or absolute bandwidths of more than 500 MHz. Such wide bandwidths offer a wealth of advantages for both communications and radar applications. In both cases, a large band-width improves reliability, as the signal contains different frequency components, which increases the probability(More)
This paper studies efficient and simple data broadcast in IEEE 802.15.4 based ad hoc networks (e.g., ZigBee). Since finding the minimum number of rebroadcast nodes in general ad hoc networks is NP-hard, current broadcast protocols either employ heuristic algorithms or assume extra knowledge such as position or two-hop neighbor table. However the ZigBee(More)
In this letter, a threshold selection technique for time of arrival estimation of ultra-wideband signals is proposed. It exploits the Kurtosis of the received signal samples. The dependency between the Kurtosis and optimal normalized threshold are investigated via simulations. The proposed technique yields efficient threshold selections, has low complexity(More)
A common technique for wireless positioning is to estimate time-of-arrivals (TOAs) of signals traveling between a target node and a number of reference nodes, and then to determine the position of the target node based on those TOA parameters. In determining the position of the target node from TOA parameters, linear or nonlinear least-squares (LS)(More)
he future will bring a wide variety of multimedia applications each with different traffic characteristics at optimized performance, to be carried by both wireless and wireline networks. In wireless mobile networks the offered traffic varies both temporally and spatially, with the spatial variation significantly higher than in wired networks. Models of the(More)
An image sensor network platform is developed for testing transmission of images over ZigBee networks that support multi-hopping. The ZigBee is a low rate and low power networking technology for short range communications, and it currently uses IEEE 802.15.4 MAC and PHY layers. Both ZigBee networking (NWK) and IEEE 802.15.4 MAC layer protocols are(More)
High time resolution of ultra wideband (UWB) signals facilitates very precise positioning capabilities based on time-of-arrival (TOA) measurements. Although the theoretical lower bound for TOA estimation can be achieved by the maximum likelihood principle, it is impractical due to the need for extremely high-rate sampling and the presence of large number of(More)
Ranging with energy detectors enables low-cost implementation. However, any interference can be quite detrimental to range accuracy. We develop a method that performs nonlinear filtering on the received signal energy to mitigate multiuser interference (MUI), and we test it over time hopping and direct sequence impulse radio ultra-wideband signals.(More)