limiting end-to-end delays in long-lasting sensor networks
Many applications require a lifetime of several years from a sensor network while expecting low and guaranteed end-to-end delays between sources and a sink. Obviously, these two parameters - lifetime and delay - contradict each other. In this work we present and evaluate a solution that limits the end-to-end delays and nevertheless achieves a long lifetime. We introduce a model for evaluation of delay and lifetime in multi-hop sensor networks. According to our model a network of off-the-shelf sensor nodes limits an end-to-end delay to 5 seconds and works for 8 months. However, if applications can tolerate the end-to-end delay of 20 seconds, the nodes prolong the lifetime to approx. 2 years. Our evaluation revealed that end-to-end delay affects the lifetime only to a certain limit. In our example this limit was 60 seconds, i.e. any delay change above 60 seconds does not influence the lifetime considerably.
sensor network quality of service medium access protocols clock drift energy efficiency