###### Abstract  
In this paper, we study a mixed cooperative communication system consisting of power line communication (PLC) and free-space optical communication (FSO) links, where the PLC link suffers from log-normal fading and is affected by both impulsive and background noises. Meanwhile, the FSO link undergoes Gamma-Gamma fading with both atmospheric turbulence and pointing errors. More specifically, we present closed-form expressions for the probability density function and the cumulative distribution function of the end-to-end signal-to-noise ratio of the proposed model. Consequently, the outage probability and the bit error rate (BER) performance are derived in terms of univariate Fox-H and bivariate Fox-H functions. Finally, the analytical results are verified using Monte Carlo simulations, providing useful insights into the capabilities of the proposed system.  
can benefit from the integration of PLC with FSO using relaying techniques. To transmit information signals from an indoor source to an outdoor destination using an FSO link, there are various solutions such as implementing fiber optic or Wi-Fi signal links [11]. With the former approach, the cost of implementation and maintenance can be high in some scenarios, while in the latter option, due to the presence of large obstacles and dead zones the signal fluctuations are a hindrance. However, currently, no research focuses on the cooperative transmission of the PLC-FSO relaying system. With its advantages such as cost-efficient and high rate communication, the combined deployment of the readily available PLC infrastructure with the FSO link has potential practical implementations and thus warrants investigation.  
In this paper, due to the potential for simple implementations and high energy efficiency, we consider DF relaying systems that combine PLC and FSO integration. The proposed mixed system can support wireless networks to reach remote geographical area through the ubiquitous indoor power line infrastructure. More specifically, the analytical results are provided considering the effects of both pointing errors and various types of turbulence in the FSO link, as well as the impulsive-background noise in the PLC link. We derive the probability density function (PDF) and the cumulative distribution function (CDF) for the end-to-end SNR of the proposed system. Consequently, in compilation with the Gamma-Gamma distribution of the FSO link, the log-normal distribution of the PLC link is approximated using a Gamma distribution, thereby obtaining a tractable closed-form expression of the analytical BER performance and the outage probability of the proposed system. The results demonstrate that the analytical derivation exactly matched with the Monte-Carlo simulations, providing insights into the proposed system under various channel conditions.  
The remainder of this paper is organized as follows. In Section 2, we present the descriptions of the communication system and the channel model, include the PLC and FSO channel models. In Section 3, we provide the derivation the CDF and PDF of the end-to-end SNR of proposed system. The mathematical expressions of the outage probability, the average BER, in Section 4. The diversity order of the proposed system is presented in Section 5 using asymptotic analysis at high SNR regime based on the derived outage probability. Consequently, some simulation results using Monte-Carlo simulation are presented in Section 6 to validate the mathematical correctness of the derived mathematical results. Finally, some concluding remarks are provided in Section 6.