Correction of frequency-dependent I/Q mismatches in quadrature receivers

Pun, Kong-Pang; Franca, J.E.; Azeredo-Leme, C.; Chan, Cheong-Fat; Choy, Chiu-Sing

doi:10.1049/el:20010944

Cited by 34 publications

(17 citation statements)

References 5 publications

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“…By making a choice which is a priori favorable for the proposed delay-based compensation (e.g., ladder Butterworth) a simple and effective I/Q compensation is possible. When the I/Q-imbalance con straint is ignored, laborious and costly frequency-dependent I/Q correction schemes [10], [12], [14], [15] are inevitable.…”

Section: B Various Filters Discussionmentioning

confidence: 99%

“…Off-line estimation methods use one [5], [9] or multiple [10], [11] test tones and a measurement (FFT) block, or test-signal based adaptive tuning algorithms [12], [13]. Training signals are avoided in [8], [14], [15], which use blind, on-line adaptive methods to estimate and correct the I/Q imbalance.…”

mentioning

confidence: 99%

“…Thus, the implementation of the correction matrix becomes costly since it should be effective over the whole band of interest. Published frequency-dependent I/Q estimation/correc tion methods [10], [12], [14], [15] treat the zero-IF filters as a black box. However, its behavior can a priori be predicted (presented in Section II) and used to considerably simplify the compensation hardware (presented in Section III).…”

mentioning

confidence: 99%

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One-Tap Wideband I/Q Compensation for Zero-IF Filters

Kiss¹,

Prodanov²

2004

IEEE Trans. Circuits Syst. I

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Abstract-The I/Q imbalance is one of the performance bot tlenecks in transceivers with stringent requirements imposed by applications such as 802.11a. The mismatch between the frequency responses of two analog low-pass filters, used, e.g., for channel selection in zero-IF receivers, makes this I/Q imbalance frequency dependent. Usually, frequency-dependent I/Q mismatch is esti mated and corrected by adaptive techniques, which are complex to implement and may converge slowly due to noise. In this work, a simple, delay-based I/Q compensation scheme is proposed based on an extensive statistical analysis. Its digital implementation uses only two coefficients, which are tuned by a one-step two-tone error estimation. Simulations show that this hardware-efficient scheme significantly reduces the I/Q imbalance. Fig. 1. Usually, the RX chain in cludes an antenna (A), a low-noise amplifier (LNA), a pair of mixers driven by quadrature local-oscillator (LO) signals I ( ) and Q ( ), a pair of real low-pass filters (LPFs), a pair of analog-to-digital converters (ADCs) sampled at , and a digital signal processor (DSP) [3]. An orthogonal frequency-division multiplexing (OFDM) DSP, used in 802.11a [4], inherently contains a fast-Fourier transform (FFT) block. A zero-IF transmitter (TX) chain starts with a DSP and is followed by a pair of digital-to-analog converters (DAC), a pair of LPFs, a mixer/LO block, a power amplifier (PA), and an antenna [3]. Index Terms-ComplexThe main contributors of the RX or TX chain's I/Q imbal ance 1 are the gain error ( ) of the mixers, the phase error ( ) in the LO signals, the gain ( ) and phase ( ) mismatch between the LPF's transfer functions, and, finally, the gain error ( ) between the data converters (ADCs in RX, DACs in TX). The I/Q imbalance contribution of gain and phase errors can be modeled as a two-input two-output linear network with some inter-coupling coefficients [5]. These simple models can be individually applied to each block of mixers/LO, LPFs,

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Section: B Various Filters Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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One-Tap Wideband I/Q Compensation for Zero-IF Filters

Kiss¹,

Prodanov²

2004

IEEE Trans. Circuits Syst. I

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“…Most of the work reported in the literature focuses on compensation of frequencyindependent I/Q imbalances (see, e.g., [7,10,23,74,75,[89][90][91][92][93][94][95][96] and the references therein). This being the case, the imbalanced signal can be written as (see also Section 15.2.2 for explicit definition of the complex coefficients K 1 and K 2 as functions of the imbalance values) (15.24) where g and model the amplitude and phase imbalances, here referred to the Q branch.…”

Section: I/q Imbalance Compensation Principlesmentioning

confidence: 99%

RF Impairment Compensation for Future Radio Systems

Hueber

Staszewski²

2010

Multi‐Mode/Multi‐Band RF Transceivers for Wireless Communications

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“…I/Q imbalance and its mitigation have been studied intensively [7][8][9][10][11][12][13][14][15][16]. The application of I/Q imbalance compensation techniques available in literatures is mainly developed for the communication receivers such as quadrature receivers [7][8][9] and orthogonal frequencydivision multiplexing (OFDM) receivers [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Wideband in‐phase/quadrature imbalance compensation using finite impulse response filter

Cheng

Liou

Lin

et al. 2014

IET Radar, Sonar & Navigation

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The authors proposed an in-phase/quadrature (I/Q) imbalance compensation technique for wideband digital receiver applications. An I/Q channel-based receiver can double the receiver working bandwidth. However, the amplitude/phase imbalance of an imperfect hybrid coupler can generate image signals thus reducing the receiver's instantaneous dynamic range. They developed a finite impulse response filter-based technique to mitigate deleterious effects because of the amplitude/phase imbalance. Both simulations and experiments were conducted to verify validity of the developed algorithm. The simulation and experiment results show that the proposed imbalance mitigation technique can reduce image signal powers by more than 24 dB or down to noise level. A receiver system level simulation is also conducted to demonstrate the practicality of the proposed imbalance mitigation method.

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Correction of frequency-dependent I/Q mismatches in quadrature receivers

Cited by 34 publications

References 5 publications

One-Tap Wideband I/Q Compensation for Zero-IF Filters

One-Tap Wideband I/Q Compensation for Zero-IF Filters

RF Impairment Compensation for Future Radio Systems

Wideband in‐phase/quadrature imbalance compensation using finite impulse response filter

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