IQ imbalance compensation for OFDM based wireless LANs

Zero-IF architecture has become popular for WLAN receivers due to its simplicity. However, zero-IF receivers suffer from the effect of IQ imbalance and carrier frequency offset which may have huge impacts on their performance. Several joint compensation schemes for these influences have been researched, based on the correlation between adjacent channel frequency responses. However, by the limitation assuming the perfect symbol synchronization, these schemes show performance degradation when a symbol timing error exists. In this paper, we analyze the effect of symbol timing errors and propose a robust and efficient compensation scheme. Simulation results show the proposed algorithm achieves an SNR gain of 7.3dB over the conventional algorithm when a symbol timing error occurs.