Jyotshana Kanti

Reliable spectrum sensing scheme based on dual detector with double-threshold for IEEE 802.22 WRAN

In this paper, a reliable spectrum sensing (SS) scheme using dual detectors for IEEE 802.22 WRAN has been presented. In dual or double detectors, first one detector is energy detector (ED) with fixed threshold (FT), while second one is ED with adaptive double threshold (ADT). Numerical results shows that proposed reliable scheme improves detection performance and outperforms the cyclostationary based sensing method and adaptive SS by 12.9% and 15% at −8 dB signal-to-noise ratio (SNR), respectively. It also shows that the proposed scheme takes smaller detection time period than cyclostationary detection and adaptive SS scheme in the order of 5 ms and 0.8 ms at −20 dB SNR, respectively. Moreover, the scheme analyzes in conjunction with cooperative spectrum sensing (CSS) where each CRs work together in order to take final or global decision. It is observed that the proposed sensing scheme with CSS achieves spectrum detection performance in the order of 0.9 for SNR value of as low as −17.5 dB when numbers of CRs are ten.

Improved sensing detector for wireless regional area networks

Abstract In wireless communication, noise and fading affect the radio signals. Multiple antennas one of the solutions to nullify these affects. In this paper, authors proposed an improved sensing detector for wireless regional area networks. The presented scheme uses two detectors concept, detectors imply multiple antennas, follows selection combination to select best signals. The proposed model not only improves the detection performance but also decreases the sensing time. Out of the two detectors the first one is energy detector with single adaptive threshold and second one is energy detector with two adaptive thresholds. The thresholds are adaptive as they are dependent on noise variance (), and the value of this noise variance changes according to the noise signal. Both the detectors work simultaneously and their output is then fed to a decision devise which takes the decision using OR rule. In the proposed scheme more than one antenna has been used and is compared with existing sensing techniques. Results show that the proposed an improved sensing detector technique while number of antennas (Nr) = 2, improves the detection performance by 24.6, 53.4, 37.9, and 49.6%, as compared to existing schemes (i.e. EDT-ASS-2015 scheme, ED and cyclo-2010, adaptive SS-2012, and conventional-ED) scheme at −12 dB SNR respectively. Meanwhile, proposed technique also decreases sensing time in the order of 47.0, 49.0, and 53.2 ms as compared to existing schemes (EDT-ASS-2015, Adaptive SS-2012, and ED and Cyclo-2010) scheme at −20 dB SNR respectively. Further, in cooperative SS the local decisions from each cognitive radio are transferred to a fusion center which makes the final decision and shares the decision to every cognitive radio. It is also found that the proposed detection technique with CSS when number of CR users (k) = 10, and Nr = 2, achieves spectrum detection performance in the order of 0.9 for SNR value of as low as −20 dB.

A Novel Multiple Antennas Based Centralized Spectrum Sensing Technique

In wireless communication, sensing failure, reliability, and fading affects the radio signals. Adaptive threshold and multiple antennas are one of the solutions of such problems. In this paper, authors introduced a novel multiple antennas based centralized spectrum sensing SS technique for cognitive radio networks CRNs. This paper is divided into two parts: part A uses multiple antennas based improved sensing detector MA_ISD, and part B uses multiple antennas based centralized spectrum sensing MA_CSS technique. Now, in the part A: the presented scheme uses two detectors TD concept, first one is an energy detector with a single adaptive threshold ED-SAT and the second one is an energy detector with two adaptive thresholds ED-TAT. Both detectors imply multiple antennas, following selection combination to select best signals. The proposed model enhances the detection performance and takes less sensing or detection time. The thresholds are adaptive as they are dependent on noise variance

Quality Analysis of Cognitive Radio Networks Based on Modulation Techniques

\sigma_{\omega }^{2}

Various Sensing Techniques in Cognitive Radio Networks: A Review

, and the value of this noise variance changes according to the noise signal. Both the detectors work simultaneously and their output is then fed to a decision device which takes the decision using an OR rule. Results confirm that the presented multiple antennas based improved sensing detector MA_ISD technique improves the detection performance by 24.6%, 53.4%, 37.9%, and 49.6%, as compared to existing schemes i.e. EDT-ASS-2015 scheme, ED and cyclo-2010, adaptive SS-2012, and conventional-ED scheme at -12i¾?dB signal-to-noise ratio SNR, respectively, while the number of antennas Nri¾?=i¾?2. Meanwhile, proposed technique also decreases sensing time in the order of 47.0i¾?ms, 49.0i¾?ms, and 53.2i¾?ms as compared to existing schemes EDT-ASS-2015, Adaptive SS-2012, and ED and Cyclo-2010 scheme at -20i¾?dB SNR respectively. Further, in the part B: cooperative SS CSS is introduced in which the local decisions from each cognitive radio are transferred to a fusion center FC that decides the final decision and shares the decision to every cognitive radio. It is also found that the proposed detection technique with CSS when a number of cognitive radio CR users ki¾?=i¾?10, and Nri¾?=i¾?2, achieves detection performance as per IEEE 802.22 at very low SNR i.e. -20i¾?dB.

Solution of sensing failure problem: an improved two-stage detector

There are two types of sensing techniques available for spectrum sensing in cognitive radio networks (CRNs), signal specific sensing and blind sensing. Blind sensing is more popular because it does not require prior information of primary users (PUs). Conventional-energy detector (C-ED) is one of the examples of blind sensing technique, ease to implement and simplicity are main features of C-ED but at low signal to noise ratio (SNR) its performance degrades. The main factor of performance degradation is sensing failure problem which occurs at low SNR. In this paper, we introduce an improved-energy detector with adaptive double threshold (I-ED-ADT) sensing scheme to overcome sensing failure problem. In this method, each CR makes a local decision in the form of binary bit (0 or 1) when observed energy lies out of the confused region or lies within the confused region. Further, ED-ADT detector uses cooperative sensing where final decision about the presence or absence of PU signal is taken at fusion center (FC) after processing the received decisions. We have carried out MATLAB simulation tool to prove the superiority of the sensing technique in achieving a tradeoff between sensing time and detection performance.

A parallel spectrum sensing technique for cognitive radio

Cognitive radio network (CRN) is a 5-G future technology which is helpful to mitigate band width crises. There are several factors that are responsible to improve CRN quality such as modulation, routing protocols, and transmission power, etc. In this paper, we have analyzed various modulation techniques like QPSK, QAM-16, & QAM-64, and shown that QAM-64 modulation scheme performs well in terms of throughput, and outperforms the QPSK, & QAM-16. For simulation we used Net Sim software.