A compensation scheme to allow full duplex operation in the presence of highly nonlinear microwave components for 4 G systems

Omer, Mohammad; Rimini, R.; Heidmann, P.; Kenney, J.S.

doi:10.1109/mwsym.2011.5973395

Cited by 5 publications

(8 citation statements)

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“…Therefore, an algorithm is proposed using an adaptive digital filter to cancel the distortion. Different sources of selfjamming have been similarly compensated in [2,[5][6].…”

Section: Introductionmentioning

confidence: 99%

All-digital cancellation technique to mitigate self-jamming in uplink carrier aggregation in cellular handsets

Dabag

Gheidi

Gudem

et al. 2013

2013 IEEE MTT-S International Microwave Symposium Digest (MTT)

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Future handsets employing uplink carrier aggregation to increase transmit data rates will experience severe degradation in receiver sensitivity due to intermodulation products created by the nonlinearity of switches and duplexers in the RF front end for a number of LTE band combinations. To maintain the same receiver sensitivity an all-digital cancellation algorithm is proposed that relies solely on the digital representation of the signals, a peak covariance search for time alignment, and a recursive least squares (RLS) adaptive filter. This technique provides up to 20 dB improvement of signal-tointerference-plus-noise ratio (SINR), for 5-MHz LTE signals.Index Terms -adaptive filters, least mean square, intermodulation distortion, uplink carrier aggregation.

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“…Therefore, an algorithm is proposed using an adaptive digital filter to cancel the distortion. Different sources of selfjamming have been similarly compensated in [2,[5][6].…”

Section: Introductionmentioning

confidence: 99%

All-digital cancellation technique to mitigate self-jamming in uplink carrier aggregation in cellular handsets

Dabag

Gheidi

Gudem

et al. 2013

2013 IEEE MTT-S International Microwave Symposium Digest (MTT)

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“…One of the feedforward approaches is depicted in Fig. 8 in which cancellation is done in the digital domain by using digital signal processing (DSP) techniques [8].…”

Section: A Applicationsmentioning

confidence: 99%

“…These techniques are based on copying the generated RxBN in the RF path and subtracting it from the received signal, after gain and phase compensation, either in the analog or the digital domain. However, instead of copying the RxBN, one can use a model to estimate its value and use this estimation in the cancellation process [7], [8]. Using the estimated RxBN is beneficial 0018-9480 © 2015 IEEE.…”

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confidence: 99%

“…Recently, there have been a few attempts to model the RxBN of PAs [7], [8]. In [7], the investigation was limited to only simulation, where the PA was assumed as a Wiener model consisting of a linear filter in series with a static nonlinearity.…”

mentioning

confidence: 99%

“…The paper did not discuss any real cases with experimental results and did not cover important considerations that arise in practical applications addressed in this paper. In [8], experimental measurements from a PA were considered. However, the steps required for successful modeling of the RxBN were not presented.…”

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confidence: 99%

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Modeling of Deterministic Output Emissions of Power Amplifiers Into Adjacent Receive Bands

Farsi

Gheidi

Dabag

et al. 2015

IEEE Trans. Microwave Theory Techn.

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This paper discusses the measurement and modeling of the deterministic components of power amplifier (PA) emissions into neighboring receive (Rx) bands caused by PA nonlinearity, and proposes ways to distinguish these components from stochastic components. A method is presented to determine the orders of nonlinearity that are the principal contributors to the Rx band emissions. A Volterra-based model for their estimation is proposed, along with considerations for estimation accuracy. A criterion based on the matrix condition number for efficient pruning of the Volterra-based models is also presented. The proposed techniques are verified with measurements. The proposed model can be used to gain a deeper understanding of the nonlinearity mechanisms responsible for PA spurious emissions, and offers the possibility of canceling the deterministic components to improve receiver sensitivity.Index Terms-Deterministic noise, even-order terms, matrix condition number, memory polynomials (MPs), offset multisine, power amplifier (PA) emission, pruning, receive (Rx) band noise, spectral regrowth, transmitter leakage, Volterra-based models.

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Interference cancellation for higher harmonics of supply-modulated efficient RF power amplifier systems

Omer¹,

Munir

2016

Int. J. Microw. Wireless Technol.

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In building highly efficient transmitters of today, one is forced to sacrifice linearity for efficiency. Some of the highest power amplifier efficiency figures are reported by envelope tracking (ET) amplifiers. These amplifiers can generate strong higher-order harmonics, which can lead to interference with receivers operating at the harmonic frequencies. Using non-linear interference cancellation, we can help to remove the interference being caused in those receivers. This paper looks at the problem of modeling the third and second-order harmonic emission from an ET amplifier. It derives the non-linear kernel for estimating such interference. This kernel has been rigorously expanded to show its correlation with the various harmonics and its effectiveness in predicting the harmonic content. We then set up an envelope amplifier test-bench to capture harmonic signal content and cancel it using the derived kernel model. The experiment yields excellent agreement with theory and provides a validation of the system and concept.

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A compensation scheme to allow full duplex operation in the presence of highly nonlinear microwave components for 4 G systems

Cited by 5 publications

References 0 publications

All-digital cancellation technique to mitigate self-jamming in uplink carrier aggregation in cellular handsets

All-digital cancellation technique to mitigate self-jamming in uplink carrier aggregation in cellular handsets

Modeling of Deterministic Output Emissions of Power Amplifiers Into Adjacent Receive Bands

Interference cancellation for higher harmonics of supply-modulated efficient RF power amplifier systems

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