Blind source separation based I/Q imbalance compensation

Abstract

All I/Q processing receivers for digital communications share the same problem of matching the amplitudes and phases of the I- and Q-branches. In practise, imbalances are unavoidable in the analog front-end which results in finite and usually insufficient rejection of the image frequency band. This causes the image signal to appear as interference on top of the desired signal. We propose and discuss blind adaptive source separation based I/Q imbalance compensation utilizing the assumption of instantaneous signal mixtures. The performance of the proposed structure using equivariant adaptive source separation is examined both analytically and through simulations. The results indicate that the source separation based solution can offer adequate imbalance compensation performance for most communication applications.