Joint Calibration of Transmitter and Receiver Impairments in Direct-Conversion Radio Architecture

Hsu, Chen-Jui; Sheen, Wern‐Ho

doi:10.1109/twc.2011.110811.110939

Cited by 33 publications

(16 citation statements)

References 22 publications

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“…However, even in systems with a 20% tolerance for mis-identification receiving signals exceeding 20dB SNR, emitters need to have a linear gain imbalance separation of at least 0.15. While few publications indicate measured gain imbalance values for real systems, most prior works in IQ imbalance estimation and compensation use test values on the order of 0.05 [7], [10], [12], [14]- [17], indicating the gain imbalance values necessary to obtain even 80% accuracy are not practical in real systems. Narrowing the range of gain imbalance values included in the training set would likely help combat this problem.…”

Section: F Simulation Results and Discussionmentioning

confidence: 99%

“…Using the signal model described above, all data used in the following simulations was generated with the open-source gr-signal exciter module in GNURadio [13]. Though gain and phase imbalance values for real systems are not easily found, prior works in IQ imbalance estimation and compensation use test values ranging from 0.02 to 0.82 for absolute gain imbalance and from 2 • to 11.42 • for phase imbalance, with most works used test values on the orders of 0.05 and 5 • for gain and phase imbalance respectively [7], [10], [12], [14]- [17]. Therefore, QAM signals of orders 8, 16, 32, and 64 and PSK signals of orders 2, 4, 8, and 16 were simulated with linear gain imbalances between [-0.9, 0.9], uniformly distributed, and phase imbalances between [−10 • , 10 • ], uniformly distributed, in order to incorporate all possible offset values one might see in a real system.…”

Section: Dataset Generationmentioning

confidence: 99%

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Specific Emitter Identification Using Convolutional Neural Network-Based IQ Imbalance Estimators

2019

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Specific Emitter Identification is the association of a received signal to a unique emitter, and is made possible by the naturally occurring and unintentional characteristics an emitter imparts onto each transmission, known as its radio frequency fingerprint. This work presents an approach for identifying emitters using Convolutional Neural Networks to estimate the IQ imbalance parameters of each emitter, using only raw IQ data as input. Because an emitter's IQ imbalance parameters will not change as it changes modulation schemes, the proposed approach has the ability to track emitters, even as they change modulation scheme. The performance of the developed approach is evaluated using simulated quadrature amplitude modulation and phaseshift keying signals, and the impact of signal-to-noise ratio, imbalance value, and modulation scheme are considered. Further, the developed approach is shown to outperform a comparable feature-based approach, while making fewer assumptions and using less data.

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Section: F Simulation Results and Discussionmentioning

confidence: 99%

Section: Dataset Generationmentioning

confidence: 99%

Specific Emitter Identification Using Convolutional Neural Network-Based IQ Imbalance Estimators

2019

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“…Clearly, performance degrades if some of the design conditions for optimal training sequence are violated, especially the one violates (b.1) resulting a large performance degradation. In addition, a tight lower bound for I-Q imbalance IRR is also shown, which is derived in [16].…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Nevertheless, non-optimal training only results in a slight performance degradation in this aspect. A tight upper bound on dc offset errors is also given for verifying the performance [16].…”

Section: Numerical Resultsmentioning

confidence: 99%

A New Self-Calibration Method for Transmitter and Receiver Radio Impairments in Direct-Conversion Architecture

Hsu

Sheen

2010

2010 IEEE Global Telecommunications Conference GLOBECOM 2010

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Direct-conversion radio architecture is a low-cost, small-size design for the analog front-end subsystem in a wireless communication transceiver. This architecture, however, induces radio impairments such as I-Q imbalance and dc offset that incur severe degradation in communication performance. In this paper, a new time-domain method is proposed to self-calibrate simultaneously the transmitter and receiver impairments without a dedicated analog circuit in the feedback loop. Thanks to the timedomain approach, the method is applicable to all types of systems and is able to calibrate jointly the frequency-independent I-Q imbalance, frequency-dependent I-Q imbalance, and dc offset. In addition, training sequence design is investigated to optimize the performance of calibration. Analytical and simulation results confirm the effectiveness of the proposed method.

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“…This method only compensates for the frequency-dependent I/Q imbalance at the TX. Hsu and Sheen [2] studied joint calibration methods for TX/RX RF impairments. They used a frequency offset (FO) method for joint TX/RX calibration.…”

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confidence: 99%

Self-Calibration of Joint RF Impairments in a Loopback Wideband Transceiver

Deng

Lee

et al. 2020

IEEE Access

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This research studied transmitter/receiver (TX/RX) wideband (WB) RF impairments, namely frequency-dependent, frequency-independent I/Q imbalances and DC I/Q offsets. A real-based parallel structure is proposed to estimate and calibrate TX/RX WB RF impairment factors. RX impairment estimation and compensation are performed first using a frequency offset BPSK training signal. Then, the TX impairments are calibrated using a QPSK training signal. The proposed methods exhibited the following successes. First, a commercial off-the-shelf (COTS) AD9371 RF module with impairments was calibrated. After TX/RX calibration, the improvement of error vector measurement (EVM) of an OFDM 64QAM test signal was approximately 9.42 dB. Second, for the Taiwan Industrial Technology Research Institute's WB RF module with impairments, the EVM of an OFDM 16QAM test signal was calibrated and increased by about 20 dB. In summary, the proposed techniques can overcome WB RF impairments and enable high-quality WB communication. INDEX TERMS Calibration procedures, DC I/Q offsets, frequency-dependent I/Q imbalance, frequency-independent I/Q imbalance, RF impairment. I. INTRODUCTION Direct up/down RF chipsets are commonly used in wideband (WB) communication systems such as the 5G mobile communication system and digital video broadcasting systems. These chipsets have advantages such as low cost, simple design, and small area. However, for direct up/down conversion, multiple RF chips and oscillation circuits induce the different impairments including I/Q imbalance, DC offset, transmitter and receiver nonlinearities, phase noise, and coupling effects. In these impairments, many studies have extensively discussed I/Q imbalance. WB communication systems incur two I/Q imbalance effects: frequency-independent and frequency-dependent I/Q imbalances. Specifically, RF local oscillators generate I and Q carriers with amplitude and phase imbalance effects, resulting in so-called frequency-independent I/Q imbalance. In WB systems, the I and Q channels have the different impulse response effects and exhibit frequency-selective distortion, which is called frequency-dependent I/Q imbalance. The associate editor coordinating the review of this manuscript and approving it for publication was Nagendra Prasad Pathak.

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Joint Calibration of Transmitter and Receiver Impairments in Direct-Conversion Radio Architecture

Cited by 33 publications

References 22 publications

Specific Emitter Identification Using Convolutional Neural Network-Based IQ Imbalance Estimators

Specific Emitter Identification Using Convolutional Neural Network-Based IQ Imbalance Estimators

A New Self-Calibration Method for Transmitter and Receiver Radio Impairments in Direct-Conversion Architecture

Self-Calibration of Joint RF Impairments in a Loopback Wideband Transceiver

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