KCN: Guaranteed Delivery via K-Cooperative-Nodes in Duty-Cycled Sensor Networks

Performance of multihop cooperative sensor networks depends on relaying candidate selection, optimal relay assignment, and cooperative communication. In this paper, we first propose a novel relaying candidate selection scheme (KCN-selection) to choose k-cooperative nodes (KCN) at each hop based on geographic information, while the certain number of k is initially determined based on an on-demand end-to-end (ETE) reliability in the presence of unreliable communication links. However, the pre-assigned KCN cannot ensure an optimal performance due to wireless channel dynamics. To prolong the lifetime of wireless sensor network (WSN), we schedule some part of KCN to sleep while the on-demand ETE reliability still can be guaranteed with wireless channel variations. A probabilistic ETE reliability model is built to compute optimal duty cycle for KCN in an online manner. Furthermore, a KCN based optimal relay assignment and cooperative data delivery (KCN-delivery) scheme is presented, which can provide fully stateless, energy-efficient sensor-to-sink data delivery at a low communication overhead without the help of prior neighborhood knowledge. Simulation results show that our scheme significantly outperforms existing protocols in wireless sensor networks with highly dynamic wireless channel.