Reciprocity Aware PrOtocols for Radios (RAPOR)

Reciprocity is a property of most wireless propagation media where the direction of the signal propagation does not have any impact on the channel impulse response (CIR). In other words the CIR from node 1 to node 2 is the same as the CIR from node2 to node 1 at any time instance. Additionally, in rich multipath propagation environment any node that is far enough from these two nodes experiences a CIR that is uncorrelated to the CIR between nodes 1 and 2. Using this property any two nodes that measure channel impulse responses at the same time instance (measurement instances should be well within the coherence time of the channel) can use their measurement to a) generate a secret key, b) use the measured CIR for signal pre-coding for improving throughput, and c) authenticate nodes on the network.