Symmetric Adaptive Decorrelation for I/Q imbalance compensation in narrowband receivers

Symmetric Adaptive Decorrelation (SAD) for I/Q imbalance compensation is addressed in this work. First, a simple I/Q imbalance signal model that can be used in both Low-IF and Zero-IF architectures is presented. Next, prior art of the complex valued LMS filtering for I/Q imbalance compensation, which is very similar to the SAD, is briefly analysed. It is shown that the complex valued LMS filtering can de-correlate the imbalanced I/Q signal, but a distortion factor still remains in the recovered signal. Then, a simple method for eliminating this distortion is presented.