Blind frequency-dependent IQ imbalance compensation scheme using CMA for OFDM system

Abstract

Frequency-dependent IQ imbalance will be one of the degrading factors for future wideband wireless communication systems. This paper presents a blind compensation scheme for the frequency-selective IQ imbalance that occurs in wideband OFDM transceivers. The proposed scheme uses 2-tap filters having weights calculated by a constant modulus algorithm, which does not require any training or pilot signals. We verified by computer simulation that our proposed scheme compensates for frequency-dependent IQ imbalance in OFDM transceivers. We also show some experimental results, in which a frequency-dependent IQ imbalance over 6 GHz is compensated for by our proposed scheme.