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Energy Detection in Multi-user Relay Networks
No full textIn this correspondence, detection performance of an energy detector is evaluated in multi-user relay networks equipped with single amplify-and-forward (AF) relay. The relay network is assumed to be operating over independent and identically distributed, flat Rayleigh fading channels. New expressions for average detection probability are derived for both fixed-gain and variable-gain AF relays. Furthermore, truncation error bounds are also evaluated for the respective expressions because the derived average detection probability expressions were in the form of infinite summation series. In the end, the accuracy of the derived expressions is validated with the help of simulations
Asymptotic detection performance of energy detector in fixed-gain cooperative relay networks
No full textEnergy detectors are preferred choice for spectrum
sensing in cognitive radio networks due to their low implementation
complexity. Recently, there is a lot of work being done to
analyze the energy detectors in both diversity and cooperative
relay networks. In this work, detection performance of energy
detector is analyzed in a fixed-gain cooperative relay network
with maximum-ratio combiner (MRC) at the destination. Upper
and lower bounds on instantaneous signal-to-noise ratio (SNR)
of the relay path are used in this work to mathematically tract
the analyses. Probability density function (PDF) is derived for
these asymptotic instantaneous SNR bounds to obtain upper and
lower bound expressions of average detection probability (Pd)
for the relay path transmission. Similarly, PDF is derived for
the combined signal from direct and relay path at destination
with MRC, which is then used to derive asymptotic bounds on
average Pd of the cooperative system. The derived upper and
lower bounds are tight approximations of the exact average Pd
which is also validated through simulations
"Spectrum Intelligence for Interference Mitigation for Cognitive Radio Terminals"
No full textCognitive Radio (CR) is defined as a radio that is aware
of its surroundings and adapts intelligently. While CR technology
is mainly cited as the enabler for solving the spectrum
scarcity problems by the means of Dynamic Spectrum Access
(DSA), perspectives and potential applications of the CR
technology far surpass the DSA alone. For example, cognitive
capabilities and on-the-fly reconfiguration abilities of
CRs constitute an important next step in the Communication
Electronic Warfare (CEW). They may enable the jamming
entities with the capabilities of devising and deploying advanced
jamming tactics. Analogously, they may also aid the
development of the advanced intelligent self-reconfigurable
systems for jamming mitigation. This work outlines the development
and implementation of the Spectrum Intelligence
algorithm for Radio Frequency (RF) interference mitigation.
The developed system is built upon the ideas of obtaining
relevant spectrum-related data by using wideband energy
detectors, performing narrowband waveform identification
and extracting the waveforms’ parameters. The recognized
relevant spectrum activities are then continuously monitored
and stored. Coupled with the self-reconfigurability of various
transmission-related parameters, the Spectrum Intelligence is
the facilitator for the advanced interference mitigation strategies.
The implementation is done on the Cognitive Radio
coaxial test bed architecture which consists of two Software
Defined Radio terminals, each interconnected with the computationally
powerful System-on-Module (SoM)
Cognitive Radio as the Facilitator for Advanced Communications Electronic Warfare Solutions
No full textThroughout the 1990s, Software Defined Radio (SDR) technology was viewed almost exclusively as a solution for interoperability problems between various military standards, waveforms and devices. In the meantime, Cognitive Radio (CR) – a novel communication paradigm which embodies SDR with intelligence and self-reconfigurability properties – has emerged. Intelligence and on-the-fly self-reconfiguration abilities of CRs constitute an important next step in the Communications Electronic Warfare, as they may enable the jamming entities with the capabilities of devising and deploying advanced jamming tactics. Similarly, they may also aid the development of the advanced intelligent self-reconfigurable systems for jamming mitigation. This work outlines the development and implementation of the Spectrum Intelligence algorithm for Radio Frequency (RF) interference mitigation. The developed system is built upon the ideas of obtaining relevant spectrum-related data by using wideband energy detectors, performing narrowband waveform identification, extracting the waveforms’ parameters and properly classifying the waveforms. All relevant spectrum activities are continuously monitored and stored. Coupled with the self-reconfigurability of various transmission-related parameters, Spectrum Intelligence is the facilitator for the advanced interference mitigation strategies. The implementation is done on the Cognitive Radio test bed architecture which consists of two military Software Defined Radio terminals, each interconnected with the computationally powerful System-on-Module. © 2015, Springer Science+Business Media New York
Computationally Efficient Compressive Sensing in Wideband Cognitive Radios
No full textRadio spectrum is an expensive resource and only licensed users have the right to use it. In the emerging paradigm of interoperable radio networks, the unlicensed users are allowed to use the radio frequency that is unoccupied by the licensed users in temporal and spatial manner. To support this spectrum optimization functionality, the unlicensed users are required to sense the radio environment periodically for being aware of the high-priority licensed users. Wideband spectrum sensing is a challenging task for the present analog-to-digital converters used in wireless systems due to the constraints of digital signal processing unit. Exploiting on the sparseness of the wideband signal, the spectrum can be recovered with only few compressive measurements, consequently employs relief of high-speed signal processing units. This paper presents a novel wideband sensing approach where a significant portion of wideband spectrum is approximated via compressive sensing rather than entire wideband spectrum estimation, thus reducing computational complexity for the cognitive radios. Detection performances are evaluated through spectrum estimation of the desired frequency band by means of a well-known energy detection method. Finally, reduction of computational burden and memory spaces obligation are described compared to the conventional compressive sensing preceded over a single RF chain, without interfering with the detection performances
Compressed sensing based jammer detection algorithm for wide-band cognitive radio networks
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2015 3rd International Workshop on Compressed Sensing Theory and its Applications to Radar, Sonar, and Remote Sensing, CoSeRa 2015
16 November 2015, Article number 7330276, Pages 119-123
3rd International Workshop on Compressed Sensing Theory and its Applications to Radar, Sonar, and Remote Sensing, CoSeRa 2015; Pisa; Italy; 17 June 2015 through 19 June 2015; Category numberCFP1571Z-ART; Code 118216
Compressed sensing based jammer detection algorithm for wide-band cognitive radio networks (Conference Paper)
Mughal, M.O. , Dabcevic, K., Marcenaro, L., Regazzoni, C.S.
Department of Electrical, Electronic Telecommunications Engineering and Naval Architecture - DITEN, University of Genova, Italy
View references (23)
Abstract
This paper proposes a new algorithm for jammer detection in wide-band (WB) cognitive radio networks. We consider a WB which comprises of multiple fixed length narrow-band sub-bands (SB). These SBs are occupied by narrow-band signals which can be legitimate users or a jammer. To reduce the overhead of the analog-to-digital conversion (ADC), compressed sensing (CS) is performed first. CS allows us to estimate a WB spectrum with sub-Nyquist rate sampling. After that, energy detection is applied to identify the occupied sub-bands (SB). Then, for each occupied SB, some waveform parameters such as signal bandwidth and power spectral density (PSD) levels are compared with licit user database to classify the observed signal as a licit user or a jammer. In the end, performance of the proposed algorithm is shown with the help of monte carlo simulations under different empirical setup
Cyclostationary-based jammer detection algorithm for wide-band radios using compressed sensing
No full textA new algorithm for jammer detection is proposed in this work for wide-band (WB) cognitive radio networks. First, the received WB signal, which is comprised of multiple narrow-band (NB) signals, is recovered from sub-Nyquist rate samples using compressed sensing. Compressed sensing allows us to alleviate Nyquist rate sampling requirements at the receiver A/D converter. After the Nyquist rate signal has been recovered, a cyclostationary feature detector is employed on this estimated signal to compute the cyclic features. Finally, the proposed algorithm uses the second order statistics, namely, the spectral correlation function (SCF), to classify each NB signal as a legitimate signal or a jamming signal. In the end, performance of the proposed algorithm is shown with the help of Monte-Carlo simulations under different empirical setups
sj-docx-1-onc-10.1177_11795549221084832 – Supplemental material for Body Mass Index and Diabetes Mellitus May Predict Poorer Overall Survival of Oral Squamous Cell Carcinoma Patients: A Retrospective Cohort From a Tertiary-Care Centre of a Resource-Limited Country
No full textSupplemental material, sj-docx-1-onc-10.1177_11795549221084832 for Body Mass Index and Diabetes Mellitus May Predict Poorer Overall Survival of Oral Squamous Cell Carcinoma Patients: A Retrospective Cohort From a Tertiary-Care Centre of a Resource-Limited Country by Yumna Adnan, Syed Muhammad Adnan Ali, Muhammad Sohail Awan, Nida Zahid, Muhammad Ozair Awan, Hammad Afzal Kayani and Hasnain Ahmed Farooqui in Clinical Medicine Insights: Oncology</p
Experimental Study of Spectrum Estimation and Reconstruction based on Compressive Sampling for Cognitive Radios"
No full textThis paper addresses the experimental study of
the wide band signal estimation and reconstruction using the
established compressive sampling (CS) methods. For this purpose,
a hardware test bed was setup inter-connecting a wide band
SDR based hand held military radio (SWAVE HH or HH),
vector signal generator, bi-directional coupler, attenuators, PC
and other auxiliaries. Real-world communication signals were
created by the signal generator and SWAVE HH was used to
scan these signals. The discrete samples from the HH were
collected on PC for reconstruction and application of CS. It was
shown that good reconstruction of the acquired wide band signal
is possible with sub-Nyquist rate sampling by means of signal
reconstruction under CS framework. In the end, mean squared
error (MSE) performance is shown to indicate better estimation
and reconstruction of the signal with higher compression rate
and higher sparsity
Analysis of Energy Detector in Cooperative Relay Networks for Cognitive Radios
No full textIn this paper, performance of the energy detector
is analyzed in blind cooperative relay networks operating
over independent and identically distributed (IID) Rayleigh
fading channels. First, utilizing the closed-form expression of
the probability density function (PDF) of the dual-hop relay
link along with an alternative series form representation of
the generalized marcum-Q function, exact average detection
probability expression is obtained for the dual-hop blind relay
link. After that, a closed-form PDF expression is derived for
the total received signal-to-noise ratio (SNR) of the combined
received signal, received via the relay path and direct path, at
the destination, which is assumed to be equipped with selection
combiner (SC) and energy detector. Finally, within the same
analytical framework, as established for the analysis of the
relay link, an exact average detection probability expression
for the cooperative system is derived. Since the obtained
expressions are in the form of infinite summation series,
therefore, respective series truncation error bounds are also
calculated, which can be used to compute the number of terms
required to achieve a given figure of accuracy. In the end,
analytical expressions are validated with the help of computer
simulations. It is expected that these analysis will be helpful
in quantifying the futur
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