An 802.11ax 4 &lt;inline-formula&gt; 
                     &lt;tex-math notation="LaTeX"&gt;$\times$ &lt;/tex-math&gt;
                  &lt;/inline-formula&gt; 4 High-Efficiency WLAN AP Transceiver SoC Supporting 1024-QAM With Frequency-Dependent IQ Calibration and Integrated Interference Analyzer

Kawai, S.; Ito, Ryoko; Nakata, Kengo; Shimizu, Yutaka; Nagata, Motoki; Takeuchi, Tomohiko; Kobayashi, Hiroyuki; Ikeuchi, Katsuyoshi; Kato, Takayuki; Hagiwara, Yosuke; Fujimura, Y.; Yoshioka, Kentaro; Saigusa, Shigehito; Yoshida, Hiroshi; Arai, Makoto; Yamagishi, T.; Kajihara, Hirotsugu; Horiuchi, Kazuhisa; Yamada, Hideki; Suzuki, Tomoya; Ando, Yuki; Nakanishi, Koichi; Ban, Kanako; Sekiya, Masahiro; Egashira, Yasuyuki; Aoki, Tsuguhide; Onizuka, Kohei; Mitomo, Toshiya

doi:10.1109/jssc.2018.2877168

Cited by 15 publications

(2 citation statements)

References 11 publications

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“…On the other hand, training sequence methods are easier to implement, and are widely used for power-on calibration (self-calibration) since they can implement a high-precision I/Q imbalance estimation by sending a designed training sequence [17][18][19]. Furthermore, any training sequence method for a frequency-independent I/Q imbalance calibration can be extended to calibrate a frequency-dependent I/Q imbalance by utilizing a finite-impulse response (FIR) filter in the system, since the frequency-dependent I/Q imbalance can be further compensated by changing the tap coefficient of the FIR [20,21].…”

Section: Introductionmentioning

confidence: 99%

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A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

Wang,

Gao,

Liu

et al. 2024

Electronics

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A generic transmitter (TX) I/Q imbalance self-calibration method, which was designed based on a hybrid analog and digital structure, is proposed in this paper. The whole calibration scheme was implemented using low-complexity digital–analog circuits based on a zero-force feedback loop. In order to eliminate the negative effect of local oscillator (LO) harmonics on the calibration, we used a variable-delay line (VDL) in the analog domain instead of the digital phase compensator. The prototype chip was fabricated within a 0.2∼5.0 GHz direct-conversion transmitter in a 65 nm CMOS process, and measurements found an image rejection ratio (IRR) of 65 dBc.

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Section: Introductionmentioning

confidence: 99%

“…To further reduce the frequency-dependent I/Q imbalance in the proposed system, an FIR is recommended to implement after the I/Q compensation block [16,20]. Table 1 lists many published I/Q imbalance self-calibration works.…”

mentioning

confidence: 99%

A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

Wang,

Gao,

Liu

et al. 2024

Electronics

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Constellation Design for Future Communication Systems: A Comprehensive Survey

Barrueco¹,

Montalbán

Iradier

et al. 2021

IEEE Access

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The choice of modulation schemes is a fundamental building block of wireless communication systems. As a key component of physical layer design, they critically impact the expected communication capacity and wireless signal robustness. Their design is also critical for the successful rollout of wireless standards that require a compromise between performance, efficiency, latency, and hardware requirements. This paper presents a survey of constellation design strategies and associated outcomes for wireless communication systems. The survey discusses their performance and complexity to address the need for some desirable properties, including consistency, channel capacity, system performance, required demapping architecture, flexibility, and independence. Existing approaches for constellation designs are investigated using appropriate metrics and categorized based on their theoretical algorithm design. Next, their application to different communication standards is analyzed in context, aiming at distilling general guidelines applicable to the wireless building block design. Finally, the survey provides a discussion on design directions for future communication system standardization processes.INDEX TERMS Bandwidth, communication waveforms, mobile communications, spectral efficiency, wireless communications.

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An Automatic I/Q Calibrated RF Down-Converter IC With Full-Band 48–55 dB Image Rejection and 150% Fractional IF Bandwidth for SATCOM Applications

Ma,

Hsu,

Huang

et al. 2023

IEEE Access

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This article presents a fully-integrated Ku-band CMOS down-converter for the low earth orbit satellite user downlink applications. To receive satellite signals adequately, a wideband receiver is presented with an automatic in-phase and quadrature (I/Q) mismatch calibration to carry out above 40 dB image rejection ratio (IRR) to the interferences within 2 GHz span concurrently. During the I/Q signal phase adjustment, the proposed wideband I/Q interpolator (IQI) exhibits almost a constant group delay over the wide IF signal bandwidth, which alleviates the iterative calibration between multiple frequency points in a wideband system. Also, the proposed wideband IQI has apparently less influence on signal amplitude than the reported phase interpolator and delay cell while calibrating I/Q phase imbalance. This work utilizes polyphase filters to fulfill on-chip image-rejection integration and exploits logarithmic power detector to realize I/Q mismatch indication in automatic calibration. The receiver delivers a peak measured conversion gain of 37.8 dB, an averaged noise figure of 6 dB, and below ±1.5 dB gain variation within the full signal band. Above all, the down-converter achieves not only high IRR performance but broad bandwidth at the IF frequencies from 0.3 to 2.35 GHz (48-55 dB IRR, 150% fractional IF bandwidth) without any external control, tuning, or assistance. The closest frequency proximity is no more than 0.6 GHz between the received satellite signal and image. To the best of authors' knowledge, this work demonstrates the highest fractional IF bandwidth among the reported wideband CMOS receivers with high image rejection (IRR > 40 dB).INDEX TERMS CMOS, low earth orbit (LEO) satellites, high image rejection, integrated circuit (IC), RF down-converter, auto calibration, wideband, BIST, satellite communication (SATCOM).

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An 802.11ax 4 <inline-formula> <tex-math notation="LaTeX">$\times$ </tex-math> </inline-formula> 4 High-Efficiency WLAN AP Transceiver SoC Supporting 1024-QAM With Frequency-Dependent IQ Calibration and Integrated Interference Analyzer

Cited by 15 publications

References 11 publications

A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

Constellation Design for Future Communication Systems: A Comprehensive Survey

An Automatic I/Q Calibrated RF Down-Converter IC With Full-Band 48–55 dB Image Rejection and 150% Fractional IF Bandwidth for SATCOM Applications

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