In I/Q receivers characterized by direct conversion or low-IF operations, phase imbalance between the I and Q branches stands for a substantial issue which may degrade significantly the overall link performance. An alternative solution to high cost analog components with small tolerances which make the I/Q imbalance effect negligible is to estimate and compensate it digitally. In this paper we present a novel data aided (DA) joint estimator of the carrier phase offset and the I/Q phase imbalance derived following the maximum likelihood (ML) criterion. The performance accuracy analysis proves that the proposed estimator is efficient and achieves its vector Cramer-Rao lower bound (VCRLB). Simulation results in terms of BER performance of uncoded and turbo coded systems show that the proposed imbalance compensation method, at the cost of a low additional implementation complexity of the digital receiver, allows negligible performance degradation in the context of multi-level modulation formats, such as 16-QAM and 64-QAM.

Efficient Compensation of I-Q Phase Imbalance for Digital Receivers

LOTTICI, VINCENZO
Co-primo
Writing – Review & Editing
;
LUISE, MARCO
Co-primo
Writing – Review & Editing
2005

Abstract

In I/Q receivers characterized by direct conversion or low-IF operations, phase imbalance between the I and Q branches stands for a substantial issue which may degrade significantly the overall link performance. An alternative solution to high cost analog components with small tolerances which make the I/Q imbalance effect negligible is to estimate and compensate it digitally. In this paper we present a novel data aided (DA) joint estimator of the carrier phase offset and the I/Q phase imbalance derived following the maximum likelihood (ML) criterion. The performance accuracy analysis proves that the proposed estimator is efficient and achieves its vector Cramer-Rao lower bound (VCRLB). Simulation results in terms of BER performance of uncoded and turbo coded systems show that the proposed imbalance compensation method, at the cost of a low additional implementation complexity of the digital receiver, allows negligible performance degradation in the context of multi-level modulation formats, such as 16-QAM and 64-QAM.
0-7803-8938-7
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/201599
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