Improved Mult-bit Adaptive Quantization algorithm for Physical Layer Security based on Channel Charscteristics

Wireless channel has many characteristics such as reciprocity, time variation, spatial uniqueness, etc. This paper extracted secret key from its noisy radio channel measurements at two nodes by exploiting the reciprocity of wireless channel in time division system. Therefore, the secret key could be generated with the channel estimation to overcome the drawback of the key pre-distribution mechanism. Aiming at solving the problem that the multibit adaptive quantization scheme to achieve low key generation consistency probability, the paper proposes m-windows filtering mechanism to preprocess channel eigenvalues. The simulation results show that the improved algorithm achieves higher key agreement rate and key generation rate, especially when the signal to noise ratio is low, reduce the key inconsistency rate particularly noticeable.