Supporting Monitoring Applications with Mobile Wireless Sensor Networks: the "eN Route'' Forwarding Approach

This work focuses on providing effective end-to-end (E2E) communications for critical monitoring applications through Wireless Sensor Networks. In particular, the case of frequent disconnection and reconnection has been analyzed, deriving effective routing strategies to cope with this problem. Basing on a recent IETF draft scheme, namely RPL, capable of accommodating several practical situations, a novel approach, called eN Route (NR), has been proposed. In particular, it relies on a two tier network architecture with a hybrid tree-mesh topology, which can be locally rearranged depending on link failures, mainly due to mobility. This is done in a completely distributed way by maintaining a specific neighbor table built only by sniffing data messages to not increase the signaling overhead. The proposed solutions functionalities have been described and compared in terms of connectivity efficiency, E2E path length distribution and E2E latency statistic, giving also some figures on overhead. The analyses have shown NR to achieve better results in in terms of network connectivity latency and overhead, despite some drawbacks, even though RPL is able to achieve comparable performance at the expenses of higher signaling overhead. As a consequence, it has been pointed out the way RPL future releases can profit from NR approach to improve performance.