Research On Virtual Grid-based Routing Algorithm For Mobile Sink-based WSNs

Wireless sensor networks (WSNs) are composed of a large number of micro sensor devices in a self-organized manner. These sensor nodes can perform many tasks,e.g.,information perception,data processing and communication. WSNs are application-oriented and have been applied into different domains, such as environment monitoring, battlefield reconnaissance and health care. However, sensor nodes have small size and limited battery capacity, thus leading to a short network lifetime. A routing algorithm can help reducing energy consumption and improving network lifetime. Therefore, research on energy efficient routing algorithms has become a key issue for WSNs.This paper studies virtual grid-based routing algorithms with mobile sinks,aiming at utilizing sink mobility to alleviate the hotspot problem caused by the concentration of data traffic towards the sinks. The major work is as follows:(1) To solve the hotspot problem caused by the concentration of data traffic towards the sinks, sink mobility is explored as a possible solution to this problem.Unlike static sink scenarios,the network topology becomes dynamic as the mobile sinks moves. In order to copy with the dynamic network topology, this paper proposed a virtual grid-based routing algorithm for mobile sink-based WSNs, named as Grid Routing, which combines the virtual grid-based network structure with clustering. Grid Routing partitions the monitored area into several grid clusters and utilizes dynamic routes adjustment scheme to achieve rapid reconstruction of the network topology. Simulation results demonstrate that Grid Routing shows better performance in reducing network energy consumption and improving network lifetime.(2) In allusion to a lack of monitoring caused by local node failure in a non-uniform distributed network, the approach of grid construction in Grid Routing is improved and a virtual uneven grid-based routing algorithm for mobile sink-based WSNs (VUGR) is proposed. Based on the state of each grid cluster, VUGR partitions grid clusters with bad resources into several smaller grid clusters. To avoid these smaller grid clusters to be the data concentrating center, VUGR does not include them into the moving path of mobile sinks. Comparing with the existing routing algorithms using NS2, VUGR has better network lifetime and end-to-end delay.