| In recent years,with the application of mobile networks and sensor networks,wireless communication has a great development,and secure wireless communications have also received widespread attention.The security of traditional communication schemes,such as key distribution using key agreement algorithm,is determined by the computational complexity,and its application in the actual wireless network environment is often limited by the capabilities of the terminal.The key generation scheme based on the characteristics of the wireless channel stems from Shannon's pursuit of perfect secure communication theory.It uses the unpredictability,randomness and location uniqueness of the wireless channel,and realizes the“theoretical security” of wireless communication through the symmetric random key generated in real time.This scheme is a lightweight key agreement method with lower computational complexity and faster key generation rate.Therefore,more and more researchers have begun to work on key extraction through the characteristics of wireless channel physical layer.The wireless channel feature extraction technology is based on wireless channel reciprocity.Thus,legitimate communicators can generate secure shared keys in the presence of an eavesdropper.This paper focuses on the information reconciliation method in the physical layer key generation technology,researches the wireless channel feature extraction and forward information reconciliation method based on error correction code,and analyzes time-varying wireless channel reciprocity and error correction performance of different channel coding in the simulation system and experimental system.The innovative achievements of the thesis include:1.Based on the classic physical layer key extraction method,we propose forward information reconciliation scheme using channel coding technology,which includes two parts: secret key generation and message communications.First part is composed of channel probing,quantization,Gray coding,and 8B/10 B coding,which generates a pair of highly similar but unconsistent keys.With the help of channel coding and stream encryption,this pair of keys can be usedfor message communications.This scheme avoids the communication overhead caused by information reconciliation and privacy amplification basing on wireless channel reciprocity,and improves the efficiency of secure wireless communication.2.In order to explore the influencing factors of time-varying channel reciprocity,we simulate the relative movement speed,pilot signal length,and channel estimation algorithm in three test environments.The simulation results show that the movement speed and length of the pilot signal is inversely proportional to the reciprocity.And MMSE algorithm provides stronger channel reciprocity than LS algorithm.The CSI reciprocity between communicators is better with anti-interference time-domain channel estimation algorithm.3.This paper achieves efficient forward information reconciliation using channel coding technology,and simulate the error correction performance of different error correction codes,such as BCH-SRS concatenated code,LDPC code,and Polar code.We conduct lots of simulations under time-varying channel.The simulation result shows,the performance of Polar code is higher than the other two codes in terms of decoding complexity and decoding rate.4.A real-time broadband wireless channel feature extraction system based on the GUN Radio and USRP N210 is built,and the effectiveness of the forward information reconciliation method based on error correction codes is verified under it.This system is advantage of high key generation rate(KGR).Experiments show that the KGR can obtain 32.4 bits/s when wireless channel measurement bandwidth is 12.5 MHz.And in different actual measurement environments,experimental results verify the time-varying wireless channel reciprocity and error correction performance of different channel coding codes,the experimental results are in accordance with the simulation results. |
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