相干扩时光码分多址系统的物理层安全性研究

Physical-layer security of coherent time-spreading optical code division multiple access system

从信息论安全的角度出发,用保密容量定量分析了相干扩时光码分多址(OCDMA)系统的物理层安全性,得出了系统保密容量随不同系统参数的变化关系。建立了OCDMA系统的窃听信道模型,并计算得到了系统的保密容量;以Gold码为例评估了关键系统参数(用户数M、输入光功率P和码长N)对相干扩时OCDMA系统物理层安全性的影响。结果表明相干扩时OCDMA系统具有很好的抵御光纤窃听攻击的物理层安全性;关键系统参数对提高此系统的物理层安全性有重要影响。选择合适的系统参数值可提高相干扩时OCDMA系统的安全水平。

The physical-layer security of coherent time-spreading optical code division multiple access （OCDMA） system is analyzed quantitatively from the view of security of information theory. Relation- ships between the system security capacity and different system parameters are obtained. The wiretap channel model of OCDMA system is established, and the system security capacity is calculated. Influences of key system parameters （user number M, input optical power P and code length N） on the physical-layer security of coherent time-spreading OCDMA system are examined by using Gold code as an example. Re- sults show that the coherent time-spreading OCDMA system has a very good physical-layer security against fiber tapping attacks, and the above key system parameters have important influences on improving the system physical-layer security. It can improve the security of coherent time-spreading OCDMA system by choosing the appropriate system parameter values