SOLIST or How to Look for a Needle in a Haystack? A Lightweight Multi-overlay Structure for Wireless Sensor Networks

In this paper, we consider sensor database systems. Sensors are attached to objects and queries on the objects are operated at the sensor network level. Although queries to such a system might be extremely complex, ensuring efficiently basic functionalities such as broadcast or anycast without any central element is not trivial. In this paper, we provide a suite of *-cast (anycast, k-cast, broadcast) functionalities in a fully decentralized manner. More specifically, we present the design and evaluation of SOLIST, a multi-layer structure for sensors, largely inspired from structured peer-to-peer systems providing such functionalities. The main goal of SOLIST is to limit the overall energy consumption. A type is associated to each sensor, and the *-cast functionalities are implemented at a type granularity regardless of the number of types and their distribution within the network. A typical use of such a system is sensor-based stock management. We evaluate SOLIST through simulations and show that SOLIST achieves a reasonable trade-off between performance and energy consumption.