Performance of multihop wireless networks: shortest path is not enough
ACM SIGCOMM Computer Communication Review
SPEED: A Stateless Protocol for Real-Time Communication in Sensor Networks
ICDCS '03 Proceedings of the 23rd International Conference on Distributed Computing Systems
Understanding packet delivery performance in dense wireless sensor networks
Proceedings of the 1st international conference on Embedded networked sensor systems
Taming the underlying challenges of reliable multihop routing in sensor networks
Proceedings of the 1st international conference on Embedded networked sensor systems
Impact of radio irregularity on wireless sensor networks
Proceedings of the 2nd international conference on Mobile systems, applications, and services
Temporal properties of low power wireless links: modeling and implications on multi-hop routing
Proceedings of the 6th ACM international symposium on Mobile ad hoc networking and computing
Cross-Layer Analysis of the End-to-End Delay Distribution in Wireless Sensor Networks
RTSS '09 Proceedings of the 2009 30th IEEE Real-Time Systems Symposium
Dimensioning and worst-case analysis of cluster-tree sensor networks
ACM Transactions on Sensor Networks (TOSN)
Autonomous Wireless Sensor Node for Building Climate Conditioning Application
SENSORCOMM '10 Proceedings of the 2010 Fourth International Conference on Sensor Technologies and Applications
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In many applications of wireless control networks, the latency of message delivery is an important consideration. In a lighting control network where a light switch sends a wireless message to a lamp, a worst case end-to-end latency of 200 ms or better is desired, so that the working of the switch feels 'immediate' to the end user. This paper studies the probability that latency deadlines of a few hundred ms are exceeded. We use a 802.15.4 test network, located in a real-life office environment, to evaluate and compare the effects of several re-try and re-routing strategies and different MAC parameter settings. Testing under realistic conditions, in an office environment when people are present, is important to accurately determine worst case latency performance as experienced by end users. At night, without any people in the building, performance is much better than during the day. In order to accurately observe the effect of different strategies, test runs lasting at least a week are needed. We find that retrying message delivery via a single delivery route is sub-optimal. Keeping a set of two or more candidate routes for subsequent retries greatly improves worst-case latency. We show that the use of time slotting and energy saving strategies is not necessarily incompatible with the goal of optimizing for human-observable latency.