Research On Extracting Key Technology Based On The Wireless Channel Characteristic

While 5G is the focus of a new round in the field of global mobile communication technology at home and abroad,its importance obvious improvement to the user.In order to ensure the safety of the user communication process,Higher security guarantee,support business security like identity or credit and trust from user on communication are needed to the future networks.However,high complexity security measures are restricted by the demand of high speed,low expands and green which brings to the wireless network security challenges.Shannon,in Communication Theory of Secrecy System,point out that “one-timepad” is the best security system in 1949.But Shannon proved that it is ok to achieve “one-timepad” by based on the calculation of encryption measures if the length of the key and plaintext are same.This is obvious not realistic.Although Quantum Cryptography is possible to achieve O ne-TimePad system in theory,it has yet to implement and commercial.The characteristics of wireless open channel brings security hidden danger,at the same time,the uniqueness and individuality of channel as a source of establish a new security mechanism.Therefore,it is new path to deal with the 5G security requirements to carry out the physical security technology research for exploring the implementation of “one-timepad”.Based on the above research background,the method of using the wireless channel reciprocity,spatial variability and time variability was adopted to implement quick and light weight of key distribution for physical key technology of MIMO-OFDM in futrue 5G system.It is great to realize the key extraction basis of the wireless physical layer by using OFDM sub-carrier characteristic information as legitimate public random source.Firstly,this paper expounds the process and system structure of extracting the key,and put forward the method for calculating the amplitude characteristics.Secondly it introduce the USRP and MIMO-OFDM communication system based on USRP.Then,in view of the OFDM system,this paper studies the characteristics of signal extraction and channel estimation of OFDM system on USRP.The simulation say that it is feasible for taking OFDM sub-carrier amplitude information as a source of real public random channel.At the end of the paper discussed quantitative methods based on OFDM sub-carrier amplitude information and implemented the information consultation on USRP.It is obviously that quantitative factor associated with noise by calculating the threshold of two-door threshold quantitative method.Moreover,this paper put forward a single threshold quantitative method,and determined single threshold quantization factor by the 1 bit of ratios and noise.In this paper,the proposed scheme not only consider the public random resource problem,but also simplifies interaction times from the step of key extraction process and verify the possibility of implementation key extraction under wireless channel in 5G.