Geographic convergecast in wireless sensor networks

This paper presents a novel Virtual Circle Combined Straight Routing (VCCSR) algorithm for a mobile sink to collect data in wireless sensor networks. Tree-based routing is a common scheme to collect data from sensors to a sink. Most of the previous proposed tree-like aggregation approaches are not suitable for mobile sink, because the routes between sink and sensors have to be reconstructed when a mobile sink moved. This causes a lot of link reconstruction to waste a lot of energy. The VCCSR algorithm is a structure-based routing with a virtual backbone. A set of cluster heads is located at the virtual backbone. When a mobile sink needs to collect data from sensors, a dynamic tree routing is constructed on the virtual backbone. Each cluster head is able to adjust tree routes when the mobile sink location is updated. This algorithm only needs to update the location information of mobile sink to a part of cluster heads to change their routing. This paper proposes a set of regular updating rules for the virtual structure to adjust routes effectively. The VCCSR algorithm is compared with tree-based algorithms in simulation. This paper demonstrates that a mobile sink can collect data and save energy effectively in a wireless sensor network. The VCCSR algorithm reduces the reconstructing cost so that it can prolong the network lifetime.