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UWB technology provides an excellent means for wireless positioning due to its high resolution capability in the time domain. Its ability to resolve multipath components makes it possible to obtain accurate location estimates without the need for complex estimation algorithms. In this article, theoretical limits for TOA estimation and TOA-based location(More)
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)
Wireless sensor networks are emerging as an important area for communications. They enable a wealth of new applications including surveillance, building control, factory automation, and in-vehicle sensing. The sensor nodes have to operate under severe constraints on energy consumption and form factor, and provide the ability for precise self-location 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)
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)
This paper gives a tutorial overview of ultrawide-band communications systems for sensor networks. In particular, we describe the IEEE 802.15.4a standard, which is currently being developed. While most nodes (reduced-function devices) in sensor networks usually have to consume little energy, and are constrained with respect to the complexity of the(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 short range communications, the use of RSS measurements in conjunction with TOA or TDOA leads to enhanced estimation accuracy with respect to the case where only TOA or TDOA are used. In this article, we derive the Cramer-Rao Bound (CRB) for location estimation accuracy of two different hybrid schemes: TOA/RSS and TDOA/RSS. For short ranges, the hybrid(More)