Baseband analysis of Tx leakage in WCDMA Zero-IF-receivers

Frotzscher, Andreas; Fettweis, Gerhard

doi:10.1109/isccsp.2008.4537205

Cited by 17 publications

(18 citation statements)

References 6 publications

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“…This is in contrast to the existing schemes [24,25], where the original Tx signal is used to estimate the IMD2 interference. As will be shown below, the proposed Tx-IMD2 cancellation scheme has a very low complexity employing only a single tap filter to estimate the interference.…”

Section: Stage 2: Tx-imd2 Cancellationmentioning

confidence: 94%

“…Another critical issue that appears is the Tx modulated spur interference problem that occurs in LTE-CA frequency division duplex (FDD) transceivers [22,23]. In addition, due to the non-linearities in the receiver Tx-induced second order intermodulation distortion (IMD2) interference can appear [24,25]. In the remaining part of this article, we focus on a novel joint mitigation of Tx-modulated spur and IMD2 interference for LTE-CA direct-conversion receivers.…”

Section: Fig 2 Tx Induced Modulated Spurs and Imd2 Interference Illmentioning

confidence: 99%

“…The coefficients g 1 and g 2 represent the conversion gain of the mixer for the received signal and the 2nd order signal components, respectively [24]. Due to the mismatches in the baseband IQ branch, the generated IMD2 distortion is scaled different in both the paths.…”

Section: Baseband Modeling Of the Self-interferencementioning

confidence: 99%

“…Therefore, the coefficient g 2 is complex valued. The real and imaginary part of the g 2 are determined by the receiver gain and the 2nd order input intercept point (IIP2) of the I and Q mixer and can be written as [24] …”

Section: Baseband Modeling Of the Self-interferencementioning

confidence: 99%

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Digitally-intensive transceivers for future mobile communications—emerging trends and challenges

Kanumalli

Buckel

Preissl

et al. 2018

Elektrotech. Inftech.

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This article presents an overview of the major trends and challenges involved with the design of multi-band, multi-standard digitallyintensive radio frequency transceivers for next generation mobile communications. In addition, we discuss in detail one aspect of the implementation challenges, namely the occurrence and cancellation of self-interference especially in carrier aggregation modes. For that, we present a novel digital cancellation technique to jointly compensate the self-interference caused by transmit (Tx) modulated spurs and Tx second order intermodulation distortion products (IMD2) in the receiver. This architecture exploits the underlying relation between both types of interference and offers a low-complexity solution to mitigate the Tx-IMD2 interference. Simulation results show, that the proposed technique significantly suppresses both types of interference and restores the signal-to-noise ratio of the wanted signal within 0.3 dB from its value in the absence of interference, thereby achieving 30 dB of cancellation.Keywords: RF; mobile communications; wireless communications; signal processing; interference cancellation; carrier aggregation Digital unterstützte Hochfrequenz-Transceiver für den Mobilfunk der Zukunft -Trends und Herausforderungen. Dieser Artikel gibt zunächst einen Überblick über aktuellen Trends und Herausforderungen bei der Entwicklung von Multi-Band, Multi-Standard HF-Transceivern für die nächste Mobilfunk-Generation, die einen hohen Anteil an digitaler Elektronik aufweisen. Im Anschluss wird im Detail auf ein spezielles Problem solcher Transceiver eingegangen, nämlich der Selbst-Interferenz, die durch den eigenen Sender verursacht wird und die vor allem im Carrier Aggregation-Modus auftritt. Die Problematik wird nicht nur detailliert erklärt, diese Arbeit präsentiert auch eine Methode zur Unterdrückung von Selbst-Interferenz mit den Mitteln der digitalen

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Section: Stage 2: Tx-imd2 Cancellationmentioning

confidence: 94%

Section: Fig 2 Tx Induced Modulated Spurs and Imd2 Interference Illmentioning

confidence: 99%

Section: Baseband Modeling Of the Self-interferencementioning

confidence: 99%

Section: Baseband Modeling Of the Self-interferencementioning

confidence: 99%

See 2 more Smart Citations

Digitally-intensive transceivers for future mobile communications—emerging trends and challenges

Kanumalli

Buckel

Preissl

et al. 2018

Elektrotech. Inftech.

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show abstract

“…Focusing on zero-IF receivers, the nonlinearity of the I/Q down converter generates 2nd order intermodulation products (IM2) of the leaking UL signal, which are partly located around DC and thus interfere the down converted Downlink (DL) signal [1]. This Tx Leakage (TxL) becomes a substantial problem in difficult receive conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Preamble design for the digital compensation of Tx Leakage in zero-IF receivers

Frotzscher

Fettweis

2009

2009 IEEE 10th Workshop on Signal Processing Advances in Wireless Communications

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Transmitter Leakage has a significant impact on the system performance in mobile devices using zero-IF receivers. In contrast to analog approaches, digital Tx Leakage compensation approaches can easily be reconfigured and therefore are highly attractive for future mobile devices, using software defined radios. In this contribution we present a digital Tx Leakage estimation and compensation approach, using specifically designed OFDM preambles, which are also suitable for the Uplink channel estimation.

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Digital compensation of transmitter leakage in FDD zero‐IF receivers

Frotzscher

Fettweis

2011

Trans. Emerg. Telecomms. Techs.

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Transmitter leakage (TxL) has a significant impact on the performance of frequency division duplex devices using zero‐IF receivers and thus requires a suitable compensation. In contrast to analog approaches, digital TxL compensation approaches can easily be reconfigured and therefore are highly attractive for multiband mobile devices. In this contribution, we present a system model, describing the TxL impact on the received digital baseband signal. Furthermore, we show analytically that TxL causes an additional, irreversible signal‐to‐noise loss due to the quantisation in the analog‐to‐digital converter, which limits the applicability of a digital TxL compensation. However, this signal‐to‐noise ratio loss remains negligibly small as long as the TxL interference does not exceed significantly the desired received signal. For TxL to be compensated digitally, the TxL channel needs be estimated. In this work, we present two TxL channel estimation approaches suitable for frequency flat and frequency selective channels. It is shown that the usage of these approaches mitigates effectively the TxL impact on the system performance. Thus, the system designer can allow much stronger TxL, which significantly relaxes the requirements on the transmitter–receiver isolation of the duplexer and the linearity of the analog receiver frontend. Copyright © 2011 John Wiley & Sons, Ltd.

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Baseband analysis of Tx leakage in WCDMA Zero-IF-receivers

Cited by 17 publications

References 6 publications

Digitally-intensive transceivers for future mobile communications—emerging trends and challenges

Digitally-intensive transceivers for future mobile communications—emerging trends and challenges

Preamble design for the digital compensation of Tx Leakage in zero-IF receivers

Digital compensation of transmitter leakage in FDD zero‐IF receivers

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