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.