Node Localization in Wireless Networks through Physical Layer Network Coding

Previous research on physical layer network coding (PNC) focuses on the improvements in bandwidth usage efficiency. In this paper, we propose a PNC-based node localization mechanism. When two signal sequences collide at the receiver, the starting point of collision is determined by the distances between the receiver and senders. When the signal interference results from two receivers are combined together, we can determine a hyperbola with two senders as the respective focal points. In this way, by using multiple pairs of anchor nodes as senders, we can determine multiple hyperbolas and the node position will be at the intersection point of these hyperbolas. The proposed approach does not require the wireless nodes to be equipped with any special hardware such as synchronized clocks. We propose several schemes at the physical and network layers to transform the idea into a practical approach. We also investigate the overhead, localization accuracy, and safety of the approach.