Ideas on node mobility support in schedule-based medium access

Typically, medium access control (MAC) protocols for wireless sensor networks implement synchronised periodic sleeping to conserve energy. We argue that (local) synchronisation between nodes is the main cause why MAC protocols do not efficiently support node mobility e.g. nodes waste valuable energy to resynchronise. In this paper, we present ideas on mobility support in schedule-based medium access control protocols for wireless sensor networks. The resulting MAC protocol is a hybrid protocol, which combines schedule-based access with contention-based access. The rationale is that the static part of the wireless sensor network can benefit from the high delivery ratio and support for high peak loads of schedule-based access, while mobile nodes can benefit from the natural self-organization of contention-based access. We try our protocol ideas by simulation and real-live experiments.