pTUNES: Runtime parameter adaptation for low-power MAC protocols

We present pTUNES, a framework for runtime adaptation of low-power MAC protocol parameters. The MAC operating parameters bear great influence on the system performance, yet their optimal choice is a function of the current network state. Based on application requirements expressed as network lifetime, end-to-end latency, and end-to-end reliability, pTUNES automatically determines optimized parameter values to adapt to link, topology, and traffic dynamics. To this end, we introduce a flexible modeling approach, separating protocol-dependent from protocol-independent aspects, which facilitates using pTUNES with different MAC protocols, and design an efficient system support that integrates smoothly with the application. To demonstrate its effectiveness, we apply pTUNES to X-MAC and LPP. In a 44-node testbed, pTUNES achieves up to three-fold lifetime gains over static MAC parameters optimized for peak traffic, the latter being current-and almost unavoidable-practice in real deployments. pTUNES promptly reacts to changes in traffic load and link quality, reducing packet loss by 80 % during periods of controlled wireless interference. Moreover, pTUNES helps the routing protocol recover quickly from critical network changes, reducing packet loss by 70 % in a scenario where multiple core routing nodes fail.