Secure transmission for mixed FSO-RF relay networks with physical-layer key encryption and wiretap coding

Area of Science:

• Communications Engineering
• Information Security
• Optical Communications

Background:

• Hybrid networks combining Free Space Optics (FSO) and Radio Frequency (RF) present unique security challenges.
• Malicious eavesdroppers pose a significant threat to confidential data transmission in these networks.

Purpose of the Study:

• To propose a novel secure transmission scheme for mixed FSO-RF relay networks.
• To enhance data confidentiality against eavesdropping using physical-layer security techniques.

Main Methods:

• Exploiting channel reciprocity in the FSO link for physical-layer key generation.
• Implementing encryption for FSO transmission and physical-layer wiretap coding for RF transmission.
• Dividing the transmission into two time slots for secure key generation and message relay.

Main Results:

• The key generation rate of the proposed scheme is determined.
• Analysis of connection outage probability and secrecy outage probability is performed.
• Optimal design of transmission and secrecy rates to maximize the average secrecy rate.

Conclusions:

• The proposed scheme effectively secures confidential messages in FSO-RF relay networks.
• Numerical results demonstrate superior performance in terms of average secrecy rate compared to existing methods.