120 Mbps Mobile WiMAX Scalable OFDMA Signal Transmission over RoF with SMF, DCF and Chirped FBG for Fibre Length of 792 km

Fibre attenuation and chromatic dispersion are the most important problems that create slops, changes of the frequency spectrum. Therefore the signal can only be clearly transmitted over a limited distance. In order to increase the signal transmission distance and improve the frequency spectrum we study in this paper the combination of different fibres namely single mode fibre (SMF), dispersion compensating fibre (DCF) and passive chirped fibre Bragg grating (CFBG), for use in transmitting 120Mbps mobile WiMAX scalable OFDMA signal with 3.5GHz carrier frequency and 20MHz bandwidth in Radio over Fibre (RoF) system. The DCF and CFBG are used as a dispersion compensator and specifically the high reflector CFBG is used to give the signal a linear delay across the grating band pass. In our study the WIMAX signal is transmitted through a triple symmetrical dispersion system consisting of 2xDCF (20 km) and 2xSMF (100 km) connected to SMF (24 km) and CFBG. Simulation results show that the combination of SMF, DCF and CFBG has increased the transmission distance in fibre to 792 km, and SNR and OSNR are highly satisfactory.