Decode-and-forward relaying in mixed η − μ and gamma–gamma dual hop transmission system

• Published in: IET communications Vol. 10; no. 14; pp. 1769 - 1776
• Main Authors: Sharma, Nikhil, Bansal, Ankur, Garg, Parul
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 20.09.2016
• Subjects: asymmetric dual hop relay system; average bit‐error rate; channel capacity; cumulative distribution function; decode and forward communication; decode‐and‐forward relaying; free‐space optical links; FSO link; gamma distribution; gamma‐gamma dual hop transmission system; gamma–gamma distribution; generalised η − μ distribution; Monte Carlo methods; Monte Carlo simulations; probability; probability density function; radiofrequency links; subcarrier intensity‐modulation scheme; FSO link; radiofrequency links; probability; asymmetric dual hop relay system; channel capacity; generalised η − μ distribution; gamma-gamma dual hop transmission system; decode and forward communication; Monte Carlo methods; decode-and-forward relaying; Monte Carlo simulations; gamma distribution; subcarrier intensity-modulation scheme; free-space optical links; cumulative distribution function; average bit-error rate; gamma–gamma distribution; probability density function
• ISSN: 1751-8628; 1751-8636
• DOI: 10.1049/iet-com.2015.0992

In this study, the authors carry out the performance analysis of an asymmetric dual hop relay system composed of both radio-frequency (RF) and free-space optical (FSO) links. The RF link is subject to generalised η − μ distribution, while the channel for FSO link is modelled as gamma–gamma distribution. The decode-and-forward relaying phenomena is used, where the relay decodes the received RF signal from the source and converts it into an optical signal using the sub-carrier intensity-modulation (SIM) scheme for transmission over the FSO link. The FSO link is subjected to pointing errors and account for both types of detection techniques, i.e. IM/DD and heterodyne detection. Novel exact closed-form expressions for the probability density function and cumulative distribution function of the equivalent end-to-end signal-to-noise ratio of the mixed RF/FSO system in terms of Meijer's G function are derived. Capitalising on these derived channel statistics, they provide the new closed-form expressions of outage probability and the ergodic channel capacity. They also provide the average bit-error rate for different binary modulations. Furthermore, the Monte Carlo simulations validate the analytical results.