Developing Sensor Network Applications Using the TeenyL IME Middleware ∗

One direction in the evolution of wireless sensor networks (WSNs) is in support of sense-and-react applications, where actuators are physically interspersed with the sensors that trigger them. This solution maximizes localized interactions, and therefore improves resource utilization and reduces latency w.r.t. solutions with a centralized sink. On the other hand, application development becomes more complex: the control logic must be embedded inside the network and requires appropriate coordination of the nodes’ activities. Moreover, interactions tend to become stateful, and therefore reliable communication acquires an even greater importance. This paper describes the design, implementation, and evaluation of TeenyLIME, a WSN middleware designed to address the aforementioned challenges. TeenyLIME provides application programmers with the high-level abstraction of a tuple space, shared among neighboring WSN nodes. We maintain that TeenyLIME’s constructs well support sense-and-react as well as more traditional WSN applications and services, yielding a simpler, cleaner, and more reusable design. Our claims are supported by a quantitative comparison between applications developed with TeenyLIME and with existing WSN tools. Moreover, the TeenyLIME programming model is supported by an efficient middleware implementation, including a protocol that guarantees that remote tuple space operations are performed reliably. The evaluation through simulation presented in this paper shows that our protocol is able to achieve 100% reliability even in very challenging environments (e.g., up to 80% message loss), while keeping the overhead low and proportional to the error rate.