Research on Adaptive Key Generation Method based on Phase Characteristics of Wireless Channel

With the development of wireless communication technology, the application of the physical layer key generation method based on channel characteristics is becoming more and more widespread. In this method, the selection of quantization algorithm in the quantization stage is particularly important. The poor performance of the initial key will affect the efficiency of key reconciliation, and even cause the failure of the whole key generation method. In the existing quantization algorithms, the quantization level and guard interval are fixed, so the performance of the initial key cannot always be optimized in the face of complex and changeable communication environment. Aiming at the above problems, this paper combines the adaptive adjustment of quantization level and guard interval effectively on the basis of existing multi-bit quantization algorithm. This method continues the method of deleting eigenvalues by index value in multi-bit quantization algorithm, which improves the consistency of initial key. Based on information theory, this method selects optimal quantization level on the premise that the initial key is theoretically error-free under different SNR. This method sets the guard interval based on the average error probability of the eigenvalue and the quantization level, which solves the problem of deleting too many eigenvalues when the SNR is high in the method of setting fixed guard interval. Simulation results show that this method is feasible.