Multi-user wireless channel probing for shared key generation with a fuzzy controller

Probing the wireless channel in wireless networks to generate a shared key is an increasingly interesting security topic. However, not much work has been focused on wireless channel probing in multi-user applications for Shared Key Generation (SKG). In this paper we propose a scheme of multi-user wireless channel probing using a broadcast approach and a fuzzy controller. In the proposed scheme, the concept of Desired-Weighting Factor (DWF) is introduced to meet a user's Key Generation Rate (KGR) requirement. The experimental results in this primary study show that the fuzzy controller can be used to satisfy KGR requirement by efficiently tuning the probing rate under dynamic conditions. Compared with the conventional Proportional-Integral-Derivative (PID) controller, the proposed probing scheme with a fuzzy controller may produce smaller overshoots and fewer oscillations. The fuzzy controller in the proposed scheme also stabilizes the KGR at desired values, improves the SKG accuracy, enhances the control capability, and increases the entropy rate. The study indicates that the proposed multi-user probing scheme can be used to make a trade-off between probing efficiency and the user's KGR requirement.