Hermes: a composable wireless sensor network architecture for dynamic, energy and spatiotemporal awareness
John A. Stankovic, Tian He · 2004
In this dissertation, we propose a wireless sensor network architecture with layered protocols, targeting different aspects of the awareness requirements in wireless sensor networks. Under such a unified framework, we pay special attention to the most important awareness issues in wireless sensor networks: namely dynamic awareness, energy awareness and spatiotemporal awareness. First, we propose the first spatiotemporal routing protocol for wireless sensor networks, which maintains packet delivery speed for soft real-time communication through a combination of non-deterministic forwarding and neighborhood-based feedback control. Second, we introduce the time-energy aware aggregation scheme, which increases the degree of aggregation and reduces energy consumption without jeopardizing the end-to-end delay. It is the first data aggregation scheme to take the timely delivery of messages as well as protocol overhead into account to adjust aggregation strategies adaptively in accordance with assessed traffic conditions and expected wireless sensor network requirements. Third, we also deal with dynamic awareness by proposing a new communication category based on a lazy-binding concept. The exemplar protocol (IGF) implemented under this concept dramatically increases the data delivery ratio under high mobility and high rate of node failures, compared to state of the art solutions. The first unicast protocol is all together state-free, hence extremely scalable regardless of the network and neighbor size. Finally, we provide a lightweight localization technique with a very low communication overhead to support spatial awareness of the nodes. The combination of a unique area-based Point-In-Triangulation (PIT) test and a robust aggregation makes this solution much more robust in the presence of the irregularity of the radio and random node placements, compared to current state-of-the-art solutions. All these protocols have been implemented and evaluated by simulation as well as in a networked sensor mote testbed. We unified the aforementioned protocols under the Hermes architecture. The evaluation of this integrated architecture demonstrates its performance composability and its capability to be tailored for applications with different awareness requirements. We believe that the integrated architecture, supporting various kinds of awareness requirements, lays a foundation for overall wireless sensor network research and helps bring this new paradigm into reality.