Optimization of optical signal-to noise ratio by α profile multimode fibre in wireless over fibre link

The demand of bandwidth in mobile communication is growing exponentially day-by-day, as the number of users have been increasing drastically over the span of last five years. Fibre optics has attracted much attention due to its promising performance and operational cost reduction. In this thesis, the feasibility of using multimode fibre as an inexpensive cell feed in indoor system is investigated. The proposed architecture is analyzed using signal to noise ratio versus GI multimode fibre profile parameter α, cumulative signal to noise ratio, and multipath fading in indoor environment. The objectives of this thesis are: (i)designing COFDM based radio-over-fibre communication system, (ii)analyzing the downlink and uplink performance considering impairements in the fibre and wireless channels and investigating the effect of core refractive index profile (α) on graded index RoF link, (iii)investigating the effect of COFDM cyclic prefix to the graded index multimode fibre dispersion. The performance is evaluated through theoretical analysis and simulations using Matlab. The downlink and uplink analysis are performed considering all the impairements from the air interface and the RoF link. Thereafter, numerical results are generated for the downlink and uplink to illustrate the performance of the COFDM-RoF architecture.