Full MIMO Spatial Filtering Approach for Dynamic Range Reduction in Wideband Cognitive Radios

Heuvel, J. H. C. van den; Linnartz, Jean-Paul M. G.; Baltus, Peter; Čabrić, Danijela

doi:10.1109/tcsi.2012.2189056

Cited by 22 publications

(4 citation statements)

References 25 publications

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“…Note that for a given effective isotropic radiated power (EIRP), for an N Tx antenna system, P RF out = EIRP − 20 log(N Tx ). The total power drawn by the Tx RFFE can hence be given as 6 where N s is the number of baseband streams; N s = 1 for analog BF, N s = K for K-stream hybrid BF and N s = N Tx for fully digital BF. Based on (4), the power consumption of the Tx RFFE is reported in Table I where the calculations are based considering EIRP =…”

Section: Rf Front Endmentioning

confidence: 99%

A Case for Digital Beamforming at mmWave

Dutta

Barati

Ramírez

et al. 2020

IEEE Trans. Wireless Commun.

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Due to the heavy reliance of millimeter-wave (mmWave) wireless systems on directional links, beamforming (BF) with high-dimensional arrays is essential for cellular systems in these frequencies.How to perform the array processing in a power efficient manner is a fundamental challenge. Analog and hybrid BF require fewer analog-to-digital and digital-to-analog converters (ADCs and DACs), but can only communicate in a small number of directions at a time, limiting directional search, spatial multiplexing and control signaling. Digital BF enables flexible spatial processing, but must be operated at a low quantization resolution to stay within reasonable power levels. This decrease in quantizer resolution introduces noise in the received signal and degrades the quality of the transmitted signal.To assess the effect of low-resolution quantization on cellular system, we present a simple additive white Gaussian noise (AWGN) model for quantization noise. Simulations with this model reveal that at moderate resolutions (3-4 bits per ADC), there is negligible loss in downlink cellular capacity from quantization. In essence, the low-resolution ADCs limit the high SNR, where cellular systems typically do not operate. For the transmitter, it is shown that DACs with 4 or more bits of resolution do not violate the adjacent carrier leakage limit set by 3 rd Generation Partnership Project (3GPP) New Radio (NR) standards for cellular operations. Further, this work studies the effect of low resolution quantization on the error vector magnitude (EVM) of the transmitted signal.In fact, our findings suggests that low-resolution fully digital BF architectures can be a power efficient alternative to analog or hybrid beamforming for both transmitters and receivers at millimeter wave. 2 Millimeter wave, 5G cellular, Low resolution quantizers, Digital beamforming.

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Section: Rf Front Endmentioning

confidence: 99%

A Case for Digital Beamforming at mmWave

Dutta

Barati

Ramírez

et al. 2020

IEEE Trans. Wireless Commun.

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“…While current-mode and passive-mixer techniques are well-established, N-path mixer-based reconfigurable RX have emerged as a promising candidate for realizing receivers that can select/reject signals based on their properties in the frequency/spatial/code domains. Based on demonstrations over the last decade, current and future areas of research interest include (i) further reduction in power consumption of <6 GHz N-path receivers through use of passive gain and noise cancellation techniques, (ii) design of linear wideband transimpedance amplifiers since improved mixer-linearity and >200 MHz signal bandwidths result in TIA performance limiting RX power, noise and linearity [69], [70], (iii) TIA topologies with increased close-in filtering/higher-roll off to enhance out-of-band linearity [71]- [73], (iv) low-power LO generation for multi-phase RX since that remains the most significant driver of power consumption, and (v) extending wideband reconfigurable RX architectures to the spatial-domain in MIMO RX, given the widespread use of MIMO in recent and emerging sub-6 GHz wireless links [74], [75].…”

Section: Discussionmentioning

confidence: 99%

Recent Developments in Integrated Interferer-Tolerant Receivers for Reconfigurable Radios

et al. 2021

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Fragmented spectrum allocations at RF and mm-Wave, increased use of carrier aggregation/MIMO and dense spectrum-reuse in wireless links has led to interest in the design of integrated wideband, high-linearity MIMO RX that provide low noise, blocker tolerance and reconfigurability across signal domains. In this paper, receive architectures for wide operating range and blocker tolerance are presented with a focus on recent developments in reconfigurable N-path receivers. Generalized sequence-mixing architectures that support reconfigurable frequency/spatial/code-domain rejection and filtering are described along with directions of research extending operation to wider bandwidths and higher frequencies.INDEX TERMS N-path filters, reconfigurable receivers, current-mode, passive mixers, sequence mixers, spatio spectral filtering, walsh function sequence based notch filters, blocker tolerant receivers, blocker tolerant MIMO, interference tolerant receivers.This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination.

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“…The delays for the target direction are cancelled with analog delay elements in each antenna path and the signals are summed. Spatial filtering of blockers at the summation node can relax the dynamic range performance requirements of all subsequent stages including the ADC [58,59,60], which lowers its power consumption [15,61]. Analog beamforming creates a single concurrent beam pattern [62].…”

Section: Analog Beamformingmentioning

confidence: 99%