Modeling, Estimation and Mitigation of Colored Timing Jitter for OFDMA System

The use of practical oscillators, with its inherent drift due to temperature and other environmental changes, in receivers will result in clock jitter which destroys the orthogonality between subcarriers and introduces Inter Carrier Interference (ICI). The problem will become more severe in high speed applications as Doppler induced Carrier Frequency Offset (CFO) also contributes more ICI. To alleviate the problem we develop a colored clock jitter based on practical oscillators as used in receivers. Then a joint tracking based estimation and mitigation algorithm is proposed to compensate effect of clock jitter. Specifically, using the first order variation of the phase jitter over multiple OFDMA symbols, we formulate a new objective function and an iterative jitter tracking scheme is developed for more accurate synchronization.