Network and system support for interactive embedded applications

Brown, James (2011) Network and system support for interactive embedded applications. PhD thesis, Lancaster University.

Abstract

Recent advances in a number of relevant technologies have enabled wireless embedded systems to become both smaller and more capable. This has led to a massive expansion in their use and many novel applications are emerging. Many new applications require direct user interaction and in this way they differ from embedded applications currently deployed. User interaction requires sporadic availability of resources for event handling. Furthermore, processing cannot be delayed for long, as smooth system operation must be ensured. Existing wireless embedded systems are designed to conserve resources such that energy saving goals are met and systems can support extended deployment periods. Resource conservation is primarily achieved via prediction of system usage patterns and by delaying processing. However, these strategies cannot be applied in the context of interactive applications as usage patterns are less predictable and processing cannot be delayed. Thus, existing methods are not best suited to novel interactive wireless embedded systems, and novel strategies are required. This thesis examines a set of interactive embedded applications derived from the NEMO project which are shown to include the requirements and traits discussed above. In this thesis it is shown through the design and implementation of the modular NEMO device that interactive embedded systems with a modular design and exclusive use of interrupt driven inputs are able to support interactive application requirements in terms of responsiveness and resource consumption. Core contributions of this thesis are a novel wake-up radio required for practical implementation of interrupt driven operation and a set of communication primitives required to operate a dual radio architecture. The thesis shows that in the target application scenario all existing communication protocols are out-performed by communication protocols using a dual radio. This is shown in general via theoretical comparison of state-of-the-art and dual radio communication and by evaluation based on the constructed prototype system.