**4. Methodology**

The methodology used in designing RoF system consists of familiarization with Optisystem software, designing system, generate component and simulation object, running the simula‐ tion and analyze the data. Optisystem software is used to design, construct and simulate the RoF topology.

Optisystem software is a comprehensive software that provides a platform to plan, test, and simulate optical links in the transmission layer of modern optical networks. Optisystem is also an optical communication system simulation package for the design, testing, and optimi‐ zation of virtually any type of optical link in the physical layer of a broad spectrum of optical networks, from analog video broadcasting systems to intercontinental backbones.

A system level simulator based on the realistic modeling of fiber‐optic communication systems, Optisystem, possesses a powerful simulation environment and a truly hierar‐ chical definition of components and systems. Its capabilities can be easily expanded with the addition of user components and seamless interfaces to a range of widely used tools. Optisystem is compatible with Optiwave's Optiamplifier and OptiBPM design tools. Optisystem serves a wide range of applications, from CATV/WDM network design and SONET/SDH ring design to map design and transmitter, channel, amplifier, and receiver design. Optisystem contains a MATLAB component that enables the user to call MATLAB within its environment to incorporate new components or models into the software. Optisystem uses the MATLAB.dll files to evaluate the MATLAB script in the component to perform the calculations.

Designing RoF system on Optisystem software includes generation of component, simulation object and makes connection between all of them. It is very important to design a very good topology so that the maximum performance of RoF's receiver can be achieved.
