Research On Key Generation Method With Wireless Channel

The mobility,convenience and scalability of wireless networks make it widely used.The broadcast nature of wireless communications allows all the users within range to hear the transmission,thus making it vulnerable to various attacks.Physical-layer security(PLS),using the characteristics of wireless channel to achieve secure communication,can provide information-theoretic security for wireless communications.Key generation,an active research direction of PLS,automatically generates keys at each side of two legitimate users,from the randomness of their common wireless channel.However,existing schemes suffer a low generation rate and key agreement rate.To overcome this limitation,key generation rate and key disagreement rate are considered separately.We present the non uniform guard interval quantization method and channel probing method based on threshold selection,which are used to reduce the key disagreement rate.Then,based on the analysis of the two-dimensional quantization method,a multi-interval two-dimensional quantization method is presented for high rate key generation.A detailed theoretical and simulation analysis of the proposed method is offered and compared with the existing methods in this paper.The result shows the effectiveness of the proposed method.The main work of this paper is as follows:Firstly,the non uniform protection interval quantization method is presented.The method fits the position and width of the quantization interval selectively based on the distribution characteristics of the channel measurements.On average,a wide guard interval is set up in the regions affected by noise seriously,and a narrow guard interval is set up in the regions affected by noise slightly.Secondly,combining the theoretical analysis of the key capacity and the proposed quantization method,the adaptive quantization is proposed to optimize the key generation rate consistent with the mutual information.Finally,under the condition of limited transmission power,the channel detection method based on threshold selection is presented.Theoretical analysis and simulation results demonstrate that the proposed method can effectively reduce the key disagreement rate under the condition of ensuring the key generation rate.A two-dimensional quantization method is proposed,which combines the amplitude and phase of the channel to generate the key more quickly and increases the available degrees of freedom.Through the comparison of three methods with the same thought,it is proved that the optimal performance is based on the hyperbolic interval.On this basis,a multi-interval two-dimensional quantization method is put forward,which removes the guard intervals of regions with small probability distributions.In the quantization interval,more channel measurements are available for key generation,which leads a faster key extraction.In this paper,the main performance of the proposed method is analyzed theoretically and simulated,and compared with the existing methods.