Performance Degradation due to I/Q Imbalance in Multi-Carrier Direct Conversion Receivers: A Theoretical Analysis

I/Q imbalance has been identified as one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. In particular, at the reception of multi-carrier signals the achievable error rate is strictly limited by the I/Q imbalance. Knowledge about the quantitative link between the hardware parameters and the resulting error rate is essential for a reasonable design of the receiver front-end. In this paper a novel framework for the analytical computation of the symbol error probability in multi-carrier systems is presented. We consider an arbitrary M-ary QAM modulated multi-carrier signal, which is corrupted by both a noisy Rayleigh fading channel and receiver I/Q imbalance. The theoretical results are validated exemplarily for the IEEE 802.11a WLAN standard.