Simulative Analysis of Influence of Modulation Techniques on COFDM based Radio over Fiber Transmission

Abstract

-In this paper, Coded Orthogonal Frequency Division Multiplexing (COFDM) based Radio over Fiber (RoF) system is simulated (for different bit rates) for different modulation techniques to observe impact on system parameter [quality factor (Q)]. Influence of increasing bit rates has been observed for 2 km long linear multimode fiber. To reduce dispersion due to multimode fiber, convolutional encoder (code rate ½, generator polynomial 133 8 , 171 8 ) and viterbi hard decision decoding algorithm are chosen for simulative model of COFDM based RoF system. Transmission of 32 sub-carriers with externally modulated continuous wave laser source gave satisfied results for Q values.

An LDPC-COFDM based High Speed Mobile Wireless Communication System

“…To avoid inter symbol interference (ISI) caused by multi-path fading, a guard interval of length is inserted between every COFDM symbol. During this interval, a cyclic prefix is transmitted to avoid Inter-carrier Interference (ICI) [12,13]. The Cyclic Prefix is a periodic extension of the last part of a COFDM symbol that is added to the front of the symbol in the transmitter, and is removed at the receiver before demodulation.…”