Rethinking Link-Level Abstractions for Sensor Networks

For designers of the communication stack of sensor nodes there is a constant tension between performance and modularity. To alleviate this tension, researchers have come up with a number of modular architectures. In this work we take a refreshed view of the design of an abstract link level service, an important component in the communication stack. We start with a critical review of one such service, the Sensornet Protocol (SP), and then we implement an SP-flavored link level service featuring a novel combination of ARQ and MAC. Experimental results of transmission delay and energy efficiency highlight a few subtle architectural design trade-offs we have encountered, namely semantics binding, implicit information sharing, and time scope initialization. These aspects have significant impact on software modularity in tiny sensor nodes.