Frequency-Agile Multiband Quadrature Sigma-Delta Modulator for Cognitive Radio: Analysis, Design and Digital Post-Processing

Marttila, Jaakko; Allén, Markus; Valkama, Mikko

doi:10.1109/jsac.2013.131101

Cited by 9 publications

(5 citation statements)

References 30 publications

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“…Finally, [16] aims to reduce coefficients mismatch between the I and Q paths in a multi-bit CSDM. The method consists in adding feedback paths from the inputs and outputs of the CSDM to all the integrators inputs, which allows coefficients mismatch compensation (in digital domain) based on a matrix representation of mismatched complex operations.…”

Section: B Known Implementation Methods Of Asymmetric Ntfmentioning

confidence: 99%

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Digital Complex Delta–Sigma Modulators With Highly Configurable Notches for Multi-Standard Coexistence in Wireless Transmitters

Marin

Frappé

2018

IEEE Trans. Circuits Syst. I

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This paper presents a Complex Delta-Sigma Modulator (CDSM) designed for the integration in a digital transmitter chain targeting multi-standard coexistence with nearby receivers. The use of a Delta-Sigma Modulator (DSM) has the advantage of increased performances in terms of signal-tonoise-ratio (SNR) in the band of interest. However, the resulting out-of-band noise becomes an issue for multi-standard coexistence, thus increasing the complexity of the succeeding filtering stage. These constraints could be relaxed in the DSM stage, by placing a complex zero near the frequency band, where a low noise level is needed. This is achieved by cross-coupling the In-phase (I) and Quadrature (Q) channels, thus obtaining a CDSM. A review of known design methods for CDSM revealed limitations regarding the poles/zeros optimization, and the configurability of the complex zeros placement. The proposed architecture introduces two additional cross-couplings from the I and Q quantizers' outputs in order to decorrelate the zeros placement and the poles optimization problem. Hence, the improved CDSM can be implemented using existing optimization tools, which reduces considerably the number of iterations and the computational effort. In addition, the resulting modulator can target different coexistence scenarios without the need of redesign, unlike other known methods. Simulation results show a noise level reduction of approximately 20-30 dB near specific frequency bands by the proposed CDSM scheme with respect to standard DSM. Finally, we show an efficient fine/coarse configurability mechanism, which is obtained when introducing additional delays in the cross-coupling paths. Index Terms-Delta Sigma Modulator (DSM), Complex Delta Sigma Modulator (CDSM), finite impulse response (FIR), multistandard coexistence, digital transmitter; I. INTRODUCTION ECENT progress in advanced CMOS integrated digital transmitter (TX) architectures [1] [2] has been focusing on reducing the power consumption and circuit area to follow the trend of increased data rates and signal bandwidths (BW) in communication standards, e.g. IEEE 802.11 standard.

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Section: B Known Implementation Methods Of Asymmetric Ntfmentioning

confidence: 99%

“…In the digital domain, the coefficients are subject to quantization, whereas in the analog domain the coefficients are impacted by mismatch. Mismatch between in-phase and quadrature paths can in particular be of concern in the analog implementation of complex DSMs (as shown in [16]).…”

Section: General Cdsm Design Methodsmentioning

confidence: 99%

Digital Complex Delta–Sigma Modulators With Highly Configurable Notches for Multi-Standard Coexistence in Wireless Transmitters

Marin

Frappé

2018

IEEE Trans. Circuits Syst. I

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“…However, for the LNA, adjacent blocker mitigation is another key concern [17]. Multi-band reconfigurable ADCs have also been designed to support intra-band carrier aggregation [18]. However, a power efficient and small size solution for CM digitization as desired in CM-FARAD, is currently not available and so needs to be researched.…”

Section: Concurrent Multi-band Radio Architecturesmentioning

confidence: 99%

An Independently Tunable Tri-Band Antenna Design for Concurrent Multiband Single Chain Radio Receivers

Bai

Singh

Ford

et al. 2017

IEEE Trans. Antennas Propagat.

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In this paper, a novel tunable tri-band antenna is presented for concurrent, multi-band, single chain radio receivers. The antenna is manufactured on a 50×100 mm FR4 printed circuit board (PCB), and is able to provide three concurrent, independently tunable operating bands covering a frequency range from 600 MHz to 2.7 GHz. The antenna performance is investigated for both numerical and experimental methods when using, first, varactor diodes and, second, digitally tunable capacitors (DTCs) to tune frequencies, which shows the antenna gain can be improved by up to 2.6 dBi by using DTCs. A hardware-in-the-loop test-bed provides a system level evaluation of the proposed antenna in a direct RF digitized, concurrent, tri-band radio receiver. By measuring the receiver's error vector magnitude, we demonstrate sufficient isolation between concurrent bands achieving 30 MHz of aggregated bandwidth as well as strong resilience to adjacent blockers next to each band. The data reported in this article are available from the ORDA digital repository (

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“…Dual-band power amplifiers (PAs) [6] and low noise amplifiers (LNAs) have also been presented. Multi-band reconfigurable analogue-to-digital converters (ADCs) have also been designed to support intra-band carrier aggregation [7]. However, the power efficient and small size digitisation solutions desired in CM-FARAD, are currently unavailable.…”

Section: A Farad Architecturementioning

confidence: 99%

Tunable, concurrent multiband, single chain radio architecture for low energy 5G-RANs

O’Farrell

Singh

Bai

et al. 2017

2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)

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Abstract-This invited paper considers a key next step in the design of radio architectures aimed at supporting low energy consumption in 5G heterogeneous radio access networks. Stateof-the-art mobile radios usually require one RF transceiver per standard, each working separately at any given time. Software defined radios, while spanning a wide range of standards and frequency bands, also work separately at any specific time. In 5G radio access networks, where continuous, multiband connectivity is envisaged, this conventional radio architecture results in high network power consumption. In this paper, we propose the novel concept of a concurrent multiband frequency-agile radio (CM-FARAD) architecture, which simultaneously supports multiple standards and frequency bands using a single, tunable transceiver. We discuss the subsystem radio design approaches for enabling the CM-FARAD architecture, including antennas, power amplifiers, low noise amplifiers and analogue to digital converters. A working prototype of a dual-band CM-FARAD testbed is also presented together with measured salient performance characteristics.

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Frequency-Agile Multiband Quadrature Sigma-Delta Modulator for Cognitive Radio: Analysis, Design and Digital Post-Processing

Cited by 9 publications

References 30 publications

Digital Complex Delta–Sigma Modulators With Highly Configurable Notches for Multi-Standard Coexistence in Wireless Transmitters

Digital Complex Delta–Sigma Modulators With Highly Configurable Notches for Multi-Standard Coexistence in Wireless Transmitters

An Independently Tunable Tri-Band Antenna Design for Concurrent Multiband Single Chain Radio Receivers

Tunable, concurrent multiband, single chain radio architecture for low energy 5G-RANs

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