Minimization of Timing Jitter on OFDM System using modified Sampling Technique

Very recently the use of OFDM in optical systems has attracted increasing interest. Data rates in optical fiber systems are typically much higher than in RF wireless systems.The impairments caused by timing jitter are a significant limiting factor in the performance of very high data rate OFDM systems. In this letter we show that oversampling can reduce the noise caused by timing jitter. Both fractional oversampling achieved by leaving some band-edge OFDMsubcarriers unused and integral oversampling are considered. The theoretical results are compared with simulation results for the case of white timing jitter showing very close agreement. Oversampling results in a 3 dB reduction in jitter noise power for every doubling of the sampling rate.OFDM is a multicarrier modulation scheme that provides strong robustness against intersymbol interference (ISI) by dividing the broadband channel into many narrowband sub- channels in such a way that attenuation across each sub channel stays flat. Orthogonalization of sub channels is performed with low complexity by using the fast Fourier transform (FFT).