Modeling, Based On The Mimo Wiretap Channel

The wireless network lacks the physical boundary as the broadcast characteristics of wireless communication; it is open for eavesdropper because there is no physical connection for wireless communications. Therefore, the security of wireless communications has become a key issue for the physical layer. Traditional security systems are designed on top of physical layer, while the assumption that the physical layer can provide error-free link. This thesis from the physical layer of security analysis and using the physical layer of security technology to achieve the reliability of information transmission and effective Physical layer security technology is based on Shannon's security model[1], which is to solve the border wireless communications, validity and reliability of the theoretical model. The physical layer security technology is defined as: no source encryption is required because of the low interception probability of the physical layer based on modulation, coding and channel transmission characteristics, in which no secret key need to be pre-shared between legitimate communication sides before transmission. Wire-tap[2] channel model is the physical layer of the secure transmission basic model, introduced by Wyner in 1975. In the wire-tap channel model, if the main channel is better than the eavesdropping channel, then it is possible to achieve the secure information transmission. It is still an open question how to construct wire-tap channel model effectively.This thesis established the Wyner's wire-tap channel I based on MIMO technology. Firstly, MIMO pre-coding techniques are used, which means that the sender Alice uses the channel state information to pre-coded messages before sending the messages to the channel. Then, the simulation proved that the legitimate receiver Bob has a better channel performance than the eavesdropper Eve via MIMO pre-coding. Finally, we use the dual code of Hamming code as secret code to achieve unconditionally secret communication system under MIMO wiretap -channel. Simulation results show that the error probability of Eve's received the information closes to 0.5 and Bob's error probability is almost error-free, which means that the building system can achieve unconditionally secret communications purpose.