Low Power Wireless Projects
We have several projects that explore different aspects of low power wireless communications, enabling a variety of always-connected application scenarios.
RFID Performance Testing
Radio frequency identification (RFID) may be used to automatically detect, locate and/or identify objects, making it an ideal candidate for many pervasive computing applications. As RFID technology improves in terms of cost and performance, it is increasingly being explored in a variety of applications, ranging from eldercare through to the smart supply chain. However, while passive UHF RFID has many benefits over other RFID variants, reliable operation as the tag moves in the environment is inherently difficult to predict and can represent a significant challenge. It is also hard to know what effect applying the tag to an object will have.
We have developed a novel and practical experimental method called attenuation-thresholding which may be used to characterize the operating range of UHF RFID systems. It has a number of advantages over the conventional read-rate approach, but in particular it can also take account of the effects of the object that is being tagged.
- Hodges, S., Thorne, T., Mallinson, H. and Floerkemeier, C. "Assessing and Optimizing the Range of UHF RFID to Enable Real-World Pervasive Computing Applications". In A. LaMarca et al. (Eds.): Pervasive 2007, LNCS 4480, pp. 280 – 297, 2007. © Springer-Verlag Berlin Heidelberg 2007
- Mallinson, H., Hodges, S., Thorne, A. A System to Test the Performance of RFID-Tagged Objects, saint-w, p. 23, 2007 International Symposium on Applications and the Internet Workshops (SAINTW'07).
- "Determining a Better Metric for RFID Performance in Environments with Varying Noise Levels" H. Mallinson, S. Hodges and A. Thorne., 12th IEEE Interna-tional Conference on Methods and Models in Automation and Robotics, 2006.
Contact: Steve Hodges
Reducing the energy consumption of computers is becoming increasingly important with rising energy costs and environmental concerns. It is doubly important for mobile devices, whose battery lifetime is always an issue. Sleep states such as S3 (suspend) save energy but make it impossible to communicate directly with the device across the network. Therefore many people do not use S3 and instead leave their computers plugged in and active. Somniloquy enables devices to be configured so that they may be awoken from S3 based on specified network traffic such as remote desktop sessions and file transfer requests. With Somniloquy, remote servers, the network, and even applications running on the device do not have to be modified or specially configured. We will demonstrate Somniloquy in operation and show how it can be retrofitted to existing laptop and desktop computers relatively easily. This enables them to be put into suspend mode to save power more frequently than is presently practical, because application-layer reachability is maintained, making devices appear “always-on,” when they are in fact talking in their sleep.
- Yuvraj Agarwal, Steve Hodges, Ranveer Chandra, James Scott, Victor Bahl and Rajesh Gupta.
Somniloquy: Augmenting Network Interfaces to Reduce PC Energy Usage.
In Proceedings of NSDI 2009, Boston, USA, April 2009
- Sensors and Devices
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