Impact of Timing Jitter and I/Q Imbalance in OFDM Systems

Timing jitter and I/Q imbalance are each important impairments in very high data rate orthogonal frequency division multiplexing (OFDM) systems because they cause intercarrier interference (ICI) which limits the achievable bit error rate. In this paper we analyze the interaction between timing jitter and I/Q imbalance and show that this interaction introduces extra ICI terms. It is shown that the ICI is independent of received subcarrier index and has equal real and imaginary components. It is also shown that the relative contributions of I/Q imbalance and timing jitter to ICI depend on the parameter values, with I/Q imbalance dominating when timing jitter is relatively small and timing jitter dominating for larger jitter values. In all cases the extra ICI caused by the interaction is negligible. The analytical results are compared with simulation results showing close agreement.