scholarly journals Design of Cognitive Radios

2011 ◽  
pp. 87-95
Author(s):  
V D Rughwani ◽  
Sweta A Kahurke ◽  
Madhuri Pal ◽  
Prashant Rewatkar
Keyword(s):  
Spectrum Sensing ◽  
Circuit Design ◽  
Cognitive Radios ◽  
Local Oscillator ◽  
Low Noise ◽  
Frequency Synthesis ◽  
Frequency Range ◽  
Design Problems ◽  
Software Defined Radios ◽  
Noise Amplification

Cognitive radios are expected to perform spectrum sensing and communication in the frequency range of tens of megahertz to about 10 GHz. As such, they pose tough architecture and circuit design problems. This paper deals with issues such as broadband, low-noise amplification, multidecade carrier frequency synthesis, and spectrum sensing. The paper also describes the effect of nonlinearity and local oscillator harmonics, demonstrating that cognitive radios entail more difficult challenges than do software-defined radios. Multi-decade synthesis techniques and RF-assisted sensing methods are also presented.

scholarly journals Passive Switched Capacitor RF Front Ends for Spectrum Sensing in Cognitive Radios

2014 ◽  
Vol 2014 ◽  
pp. 1-20
Author(s):  
Bodhisatwa Sadhu ◽  
Martin Sturm ◽  
Brian M. Sadler ◽  
Ramesh Harjani
Keyword(s):  
Spectrum Sensing ◽  
Circuit Design ◽  
Software Defined Radio ◽  
High Speed ◽  
Cognitive Radios ◽  
Optimization Techniques ◽  
Switched Capacitor ◽  
Rf Receiver ◽  
Front End ◽  
5 Ghz

This paper explores passive switched capacitor based RF receiver front ends for spectrum sensing. Wideband spectrum sensors remain the most challenging block in the software defined radio hardware design. The use of passive switched capacitors provides a very low power signal conditioning front end that enables parallel digitization and software control and cognitive capabilities in the digital domain. In this paper, existing architectures are reviewed followed by a discussion of high speed passive switched capacitor designs. A passive analog FFT front end design is presented as an example analog conditioning circuit. Design methodology, modeling, and optimization techniques are outlined. Measurements are presented demonstrating a 5 GHz broadband front end that consumes only 4 mW power.

A single versatile wideband amplifier from LNA up to MPA

2014 ◽  
Vol 6 (1) ◽  
pp. 23-29
Author(s):  
François-Xavier Estagerie ◽  
Dominique Langrez ◽  
Jean-Luc Muraro ◽  
Jean-Louis Cazaux ◽  
Rémy Leblanc
Keyword(s):  
Noise Figure ◽  
European Space Agency ◽  
Low Noise ◽  
Frequency Range ◽  
Single Chip ◽  
Wideband Amplifier ◽  
Space Agency ◽  
Noise Amplifier ◽  
Initiative Program ◽  
Noise Amplification

This work presents a wideband amplifier, in 12–19 GHz frequency range, with noise figure lower than 1.35 and 26 dB of gain developed in the frame of European Component Initiative program, supported by European Space Agency. By using a flexible biasing, this amplifier allows us to reach a significant linearity, output power at 1 dB compression up to 19 dBm, or to reduce the DC consumption close to 210 mW. This versatility implies that a user has a low-noise amplifier) or medium power amplifier in a single chip. The D01PHS process, from OMMIC foundry, has been chosen in order to realize this MMIC, thanks to linearity capability, and also thanks to a significant potential for low-noise amplification.

60 GHz-Band Low-Noise Amplifier

2017 ◽  
Vol 26 (05) ◽  
pp. 1750075 ◽  
Author(s):  
Najam Muhammad Amin ◽  
Lianfeng Shen ◽  
Zhi-Gong Wang ◽  
Muhammad Ovais Akhter ◽  
Muhammad Tariq Afridi
Keyword(s):  
Transmission Line ◽  
Quality Factor ◽  
Noise Figure ◽  
Cmos Technology ◽  
Low Noise ◽  
Constant Current ◽  
60 Ghz ◽  
Frequency Range ◽  
Constant Current Density ◽  
Chip Area

This paper presents the design of a 60[Formula: see text]GHz-band LNA intended for the 63.72–65.88[Formula: see text]GHz frequency range (channel-4 of the 60[Formula: see text]GHz band). The LNA is designed in a 65-nm CMOS technology and the design methodology is based on a constant-current-density biasing scheme. Prior to designing the LNA, a detailed investigation into the transistor and passives performances at millimeter-wave (MMW) frequencies is carried out. It is shown that biasing the transistors for an optimum noise figure performance does not degrade their power gain significantly. Furthermore, three potential inductive transmission line candidates, based on coplanar waveguide (CPW) and microstrip line (MSL) structures, have been considered to realize the MMW interconnects. Electromagnetic (EM) simulations have been performed to design and compare the performances of these inductive lines. It is shown that the inductive quality factor of a CPW-based inductive transmission line ([Formula: see text] is more than 3.4 times higher than its MSL counterpart @ 65[Formula: see text]GHz. A CPW structure, with an optimized ground-equalizing metal strip density to achieve the highest inductive quality factor, is therefore a preferred choice for the design of MMW interconnects, compared to an MSL. The LNA achieves a measured forward gain of [Formula: see text][Formula: see text]dB with good input and output impedance matching of better than [Formula: see text][Formula: see text]dB in the desired frequency range. Covering a chip area of 1256[Formula: see text][Formula: see text]m[Formula: see text]m including the pads, the LNA dissipates a power of only 16.2[Formula: see text]mW.

scholarly journals Novel filter bank-based cooperative spectrum sensing under practical challenges for beyond 5G cognitive radios

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sener Dikmese ◽  
Kishor Lamichhane ◽  
Markku Renfors
Keyword(s):  
Spectrum Sensing ◽  
Filter Bank ◽  
Cooperative Spectrum Sensing ◽  
Minimum Energy ◽  
Cognitive Radios ◽  
Spectrum Management ◽  
Wireless Channel ◽  
First Case ◽  
Channel Effects

AbstractCognitive radio (CR) technology with dynamic spectrum management capabilities is widely advocated for utilizing effectively the unused spectrum resources. The main idea behind CR technology is to trigger secondary communications to utilize the unused spectral resources. However, CR technology heavily relies on spectrum sensing techniques which are applied to estimate the presence of primary user (PU) signals. This paper firstly focuses on novel analysis filter bank (AFB) and FFT-based cooperative spectrum sensing (CSS) techniques as conceptually and computationally simplified CSS methods based on subband energies to detect the spectral holes in the interesting part of the radio spectrum. To counteract the practical wireless channel effects, collaborative subband-based approaches of PU signal sensing are studied. CSS has the capability to relax the problems of both hidden nodes and fading multipath channels. FFT- and AFB-based receiver side sensing methods are applied for OFDM waveform and filter bank-based multicarrier (FBMC) waveform, respectively, the latter one as a candidate beyond-OFDM/beyond-5G scheme. Subband energies are then applied for enhanced energy detection (ED)-based CSS methods that are proposed in the context of wideband, multimode sensing. Our first case study focuses on sensing potential spectral gaps close to relatively strong primary users, considering also the effects of spectral regrowth due to power amplifier nonlinearities. The study shows that AFB-based CSS with FBMC waveform is able to improve the performance significantly. Our second case study considers a novel maximum–minimum energy detector (Max–Min ED)-based CSS. The proposed method is expected to effectively overcome the issue of noise uncertainty (NU) with remarkably lower implementation complexity compared to the existing methods. The developed algorithm with reduced complexity, enhanced detection performance, and improved reliability is presented as an attractive solution to counteract the practical wireless channel effects under low SNR. Closed-form analytic expressions are derived for the threshold and false alarm and detection probabilities considering frequency selective scenarios under NU. The validity of the novel expressions is justified through comparisons with respective results from computer simulations.

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