A gradient routing protocol for wireless sensor networks with mobile sinks using zone based approach

Low power and lossy networks (LLNs) is an active area of research due to their large number of potential applications in different environments like health, environment monitoring and entertainment domain.

 Many protocols are proposed for routing in these networks. IETF has done one major contribution as it has developed  a proactive gradient based routing protocol for low power and lossy networks (RPL). However, for a network having few mobile sinks calculating gradients using proactive approach is costly in terms of energy.

This research proposes an efficient hybrid routing protocol for LLNs with mobile sinks. The proposed protocol provides a combination of reactive and proactive approaches for route establishment to enhance RPL for efficiently handling movement of multiple sinks. DAGs are only maintained by nodes close to the sink within a certain zone. While the nodes outside the zone use on-demand sink discovery to find the closest possible sink, without maintaining DAGs. This helps to decrease the number of retransmissions resulting in low standing cost for maintaining DAGs and enhances the network life time especially mobility of sink.

Analysis of simulation results show that the performance of the proposed approach is much better than RPL approach.