Investigation of Near Field Inductive Communication System Models, Channels and Experiments

Abstract—Near-field inductive channels created between two or more magnetically coupled inductive nodes are studied in this paper. Peerto-peer configurations and array architectures are discussed. The array channels are used for cooperative relaying with inductive methods with potential to provide range extension and enhanced data rate access in magnetic induction communication systems. The received power shows the presence of the nearest neighbour interactions and the influences of higher order coupling from nodes two or more positions away from the receiver. This influence causes phase changes in the communication system. Four methods of exciting the antenna arrays are proposed. These are array edge excitation, center excitation, collinear array excitation and multi-array excitation. Experiments with hardware nodes show that while array edge excitation provides increased power at the array edge, it is out performed by array center excitation which results to twice the power captured at the array center node compared to the power captured at edge excited first element. We demonstrate by example that a receiver is influenced most by its neighbouring nodes on both sides and that the effects of second and third tier neighbours are relatively insignificant. 1.