A lightweight ring-based routing protocol for wireless sensor networks with mobile sinks

In this paper, we design a novel lightweight ring-based routing protocol (LRRP) for wireless sensor network with mobile sinks (mWSN). The design objective is to significantly reduce the protocol overhead for route discovery and management while preserving high routing performance. For this purpose, LRRP builds a base ring by finding a shortest cycled path surrounding an artificially created topological hole in the network and, based on the base ring, it builds a ring-based structure to cover remaining nodes in the network and further assigns them ring IDs and virtual angles to ease the packet forwarding. LRRP works in a hybrid way for routing updates and packet forwarding. Specifically, each mobile sink (MS) dynamically chooses agent nodes, one on each ring, to proactively update its reachability as it moves. Each data packet is forwarded using ring-based forwarding along a pre-selected ring until reaching an MS or an agent node with path to an MS, from which the packet will be directly forwarded towards the MS. LRRP further considers how to achieve a good tradeoff between energy balancing among different rings and data path lengths. Extensive simulation results show that LRRP can significantly reduce the protocol overhead and achieve prolonged network lifetime as compared with existing work while achieving a very high packet delivery ratio.