Energy-efficient data collection method with multiple deadlines for wireless sensor networks

In this paper, we focus on a monitoring environment with wireless sensor network in which multiple mobile sink nodes traverse a given sensing field in different spatial-temporal patterns and collect various types of environmental data with different deadline constraints. For such an environment, we propose an energy-efficient data collection method that reduces intermediate transmission in multi-hop communication while meeting predetermined deadlines. The basic approach of the proposed method is to temporarily gather (or buffer) the observed data into several sensor nodes around the moving path of the mobile sink that would meet their deadlines at the next visit. Then, the buffered data is transferred to the mobile sink node when it visits the buffering nodes. We also propose a mobile sink-initiated proactive routing protocol with low cost (MIPR-LC) that efficiently constructs routes to the buffering nodes on each sensor node. Moreover, we simulate the proposed collection method and routing protocol to show their effectiveness. Our results confirm that the proposed method can gather almost all of the observed data within the deadline, while reducing the intermediate transmissions by 30%, as compared with an existing method. In addition, the MIPR-LC method can reduce the transmissions for the route construction by up to 12% when compared with a simple routing protocol.