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Frequency-selective joint Tx/Rx I/Q imbalance estimation using golay complementary sequences

Abstract:

The increasing use of smaller technologies in the manufacture of analog front - ends (AFEs) for communication systems has increased the impact their non - ideal components produce. This results in a significant degradation of the system performance that must be identified and addressed. In particular, the I/Q imbalance is commonly estimated and compensated via digital signal processing techniques using training sequences. In order to preclude the rise of other non - idealities, such as the non - linearity of the power amplifier (PA), these training sequences should be chosen to have a low peak - to - average power ratio (PAPR). In addition, it is desirable that these techniques have reduced computational complexity for minimizing estimation times and area resources. This paper presents a novel I/Q imbalance estimation algorithm that is computationally simple, it only requires adders and shifters, while exhibiting a PAPR ≤ 2. It can include the transmitter and receiver I/Q imbalances as well as the multipath phenomena. It is based on a newly used property of Golay complementary sequences (GCS). The statistical efficiency and low complexity of the proposed algorithm are proved, while its flexibility is illustrated under several extreme test cases. © 2002-2012 IEEE.