Coordination-free Repeater Groups in Wireless Sensor Networks

In this paper, we introduce the concept of repeater groups, in which a group of nodes collaborates to jointly receive incoming packets and transmit them further to a dedicated destination node, which can for instance be an actuator. The spatial diversity of wireless channels is both used to improve the chances that incoming packets are received by some group members (and subsequently by all awake members), and to make sure that the destination receives copies of the packet over several independently faded channels. The goal is hence to provide a combination of spatial and time diversity. Specifically, we investigate a class of schemes in which the group members possess a-priori knowledge about the group but avoid any explicit coordination. We discuss the design of a baseline scheme and of an improved scheme which yields significant improvements in case of high error probabilities for incoming packets.