| With the rapid development of mobile Internet technology,wireless communication technology has penetrated into every aspect of our lives.Security in wireless communications has also received increasing attention.Traditional security methods based on cryptography,however,have been severely challenged with the development of broadband and convergence of wireless communications.Physical layer security technology has become the hotspot in the field of wireless communication security.Aiming at the problem that existing physical layer encryption algorithms has weaker security and a greater impact on the original system performance.A secure transmission scheme combining LDPC-COFDM with secure coding and weak artificial noise is designed in the paper,and then the feasibility of the program is analyzed from theory and simulation.In the program the transmitted packet information is firstly encrypted scrambling coding,and then performs OFDM modulation and artificial noise superposition.To achieve a small difference in SNR between legitimate users and eavesdropping users,the differentiated channels by weak noise interference are created,and at the same time noise signals is covered by normal signals,so the safety of artificial noise signals is ensured;With this small difference in SNR,legitimate users can correctly receive information through scrambling coding,and bit the error rate of illegal users receiving information reaches around 0.5,thereby realizing data security.In this paper,the specific gengeration method of artificial noise is given,and the interference effect of artificial noise is analyzed.The performance of the algorithm is simulated and analyzed under different information packet lengths,constellation mapping methods and subcarrier numbers.The theoretical analysis and simulation results show that The proposed scheme is feasible and can guarantee the safety of algorithms and data when the artificial noise power is less than one-tenth of the normal signal power. |
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