Secret Key Capacity of Key Generation in the Slow-Fading Wireless Channels

This paper investigates the secret key capacity of key generation in the slow-fading wireless channel by considering the temporal correlation between channel measurements in the previous and current frame. We derive the analytical expression of secret key capacity in the slow-fading channel, and propose the design guideline for practical key generation schemes in slow fading channel environments. We systematically analyze the impact of all corresponding parameters on secret key capacity, including sampling period, sampling delay, eavesdroppers' location, signal-to-noise ratio, Doppler spread, and pilot length. Theoretical and simulation results indicate that secret key capacity in the slow fading channel is affected by frame-to-frame correlation and increasing transmission power or sampling period can suppress this effect.