Jitter-Robust Spectral Shaping in OFDM

Timing jitter in OFDM systems results in non-ideal sampling and pulse-shaped transmission times and thus, is an important limiting factor for practical OFDM systems. In this paper, the effect of sampling jitter on the spectrum of a transmitted OFDM signal is considered. This effect in particular can lead to a significant degradation in the performance of spectral shaping techniques in OFDM, e.g., out-of-band radiation reduction techniques, that are mostly based on the assumption of ideal sampling times and accurate synchronization. In this work, we first evaluate the effect of random sampling time jitter on the performance of the active interference cancellation (AIC) technique, a well-known out-of-band radiation reduction technique for OFDM. Then, using a minimax approach, we propose a robust scheme that takes the jitter effect into consideration and therefore, makes the sidelobe suppression technique robust against worst-case random jitter. Numerical simulations show a performance improvement of almost 3 dB in interference reduction for our proposed robust scheme in the presence of timing jitter.