The rapid growth of bandwidth demanding wireless technologies has led to the problem of spectrum scarcity. However, studies show that licensed spectrum is underutilized. Cognitive radio technology promises a solution to the problem by allowing unlicensed users, access to the licensed bands opportunistically. A prime component of the cognitive radio technology is spectrum sensing. Many spectrum sensing techniques have been developed to sense the presence or not of a licensed user. This paper evaluates the performance of the energy detection based spectrum sensing technique in noisy, fading, jamming, interference environments. Both single user detection and cooperative detection situations were investigated. Closed form solutions for the probabilities of detection and false alarm were derived. The analytical results were varied by numerical computations using Monte Carlo method with MATLAB. The performance of the computationally efficient energy detection (CE-ED) techniques were evaluated by use of Receiver Operating Characteristics (ROC) curves over additive white Gaussian noise (AWGN) and fading (Rayleigh & Nakagami-m) channels. Results show that for single user detection, the energy detection technique performs better in AWGN channel than in the fading channel models. The performance of cooperative detection is better than single user detection in fading environments.
Spectrum Sensing Detection Techniques for Overlay UsersIJMTST Journal
Spectrum allocated Agency (FCC) is currently working on the concept of white space users “borrowing” spectrum from free license holders temporarily to improve the spectrum utilization, i.e known as dynamic spectrum access (DSA). CRN systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. This project provides a tradeoff between a false alarm probability (Pf) and the signal to noise ratio (SNR) value of any spectrum detector to have a certain performance. Moreover, the performance of the cyclostationary detector (CD) and the matched filter detector (MF) is better than the energy detector(ED) especially at low signal to noise ratio values. Unfortunately, the cyclostationary spectrum sensing method, performance is not satisfying when the wireless fading channels are employed. In this project we provide the best trade off for spectrum usage for over lay users.
Spectrum Sensing Detection with Sequential Forward Search in Comparison to Kn...IJMTST Journal
FCC is currently working on the concept of white space users “borrowing” spectrum from free license
holders temporarily to improve the spectrum utilization.
This project provides a relation between a Pf and the SNR value of any spectrum detector to have a
certain performance. Previous spectrum sensing detection techniques are only suitable for Low SNR and
are based on signal information values. But these methods are purely narrow band spectrum applications
In order to overcome the above said drawbacks we propose a novel method of spectrum sensing method
and is suitable for low and high SNR values, the sensed spectrum applicable for wide band applications.
Our proposed method does not require signal information at the receiver and channel information, because
this flexibility sensing rate is very high compared to previous techniques.
Single User Eigenvalue Based Detection For Spectrum Sensing In Cognitive Rad...IJMER
Scarcity of spectrum is the issue that wireless communication technology has to deal with.
Primary user is the licensed user of the spectrum. When primary user is idle or not using the spectrum
secondary user can utilize the spectrum. This sharing of spectrum can be enabled by cognitive radio
(CR) technology. The heart of enabling this technology is spectrum sensing. Spectrum sensing involves
detection of primary signal at very low SNR (in the range of -20 dB), under noise and interference
uncertainty. This requirement makes spectrum sensing, a hard nut to crack. Another major issue in
detection is hidden node problem wherein the node in vicinity of primary transmitter also indicates
absence of the primary signal since it is hidden behind the large object. There are various algorithms
for detection viz. energy detection, matched filter detection, feature detection (cyclostationary
detection, eigen-value based detection etc.) These algorithms have limitations of complexity,
requirement of signal knowledge and detection performance. In this paper the performance of
eigenvalue based detection (EBD) method in presence of noise and low SNR of the received signal has
been evaluated for a single user.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A New Approach for Error Reduction in Localization for Wireless Sensor Networksidescitation
Localization is one of the most challenging and
important issues in wireless sensor networks (WSNs),
especially if cost effective approaches are demanded. Distance
measurement based on RSSI (Received Signal Strength
Indication) is a low cost and low complexity of the distance
measurement technique, and it is widely applied in the range-
based localization of the WSN. The RSS (Received Signal
Strength) used to estimate the distance between an unknown
node and a number of reference nodes with known co-ordinates.
Location of the target node is then determined by trilateration.
Log-normal shadowing model, can better describe the
relationship between the RSSI value and distance. Non-line
of sight and multipath transmission effects as the indoor
environment, the distance error or ranging error is large. In
this paper, experimental results that are carried out to analyze
the sensitivity of RSSI measurements in an indoor
environment for various power levels are presented. Location
error influenced by distance measure error and network
connectivity is analyzed.
Index Terms—
Spectrum Sensing Detection Techniques for Overlay UsersIJMTST Journal
Spectrum allocated Agency (FCC) is currently working on the concept of white space users “borrowing” spectrum from free license holders temporarily to improve the spectrum utilization, i.e known as dynamic spectrum access (DSA). CRN systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. This project provides a tradeoff between a false alarm probability (Pf) and the signal to noise ratio (SNR) value of any spectrum detector to have a certain performance. Moreover, the performance of the cyclostationary detector (CD) and the matched filter detector (MF) is better than the energy detector(ED) especially at low signal to noise ratio values. Unfortunately, the cyclostationary spectrum sensing method, performance is not satisfying when the wireless fading channels are employed. In this project we provide the best trade off for spectrum usage for over lay users.
Spectrum Sensing Detection with Sequential Forward Search in Comparison to Kn...IJMTST Journal
FCC is currently working on the concept of white space users “borrowing” spectrum from free license
holders temporarily to improve the spectrum utilization.
This project provides a relation between a Pf and the SNR value of any spectrum detector to have a
certain performance. Previous spectrum sensing detection techniques are only suitable for Low SNR and
are based on signal information values. But these methods are purely narrow band spectrum applications
In order to overcome the above said drawbacks we propose a novel method of spectrum sensing method
and is suitable for low and high SNR values, the sensed spectrum applicable for wide band applications.
Our proposed method does not require signal information at the receiver and channel information, because
this flexibility sensing rate is very high compared to previous techniques.
Single User Eigenvalue Based Detection For Spectrum Sensing In Cognitive Rad...IJMER
Scarcity of spectrum is the issue that wireless communication technology has to deal with.
Primary user is the licensed user of the spectrum. When primary user is idle or not using the spectrum
secondary user can utilize the spectrum. This sharing of spectrum can be enabled by cognitive radio
(CR) technology. The heart of enabling this technology is spectrum sensing. Spectrum sensing involves
detection of primary signal at very low SNR (in the range of -20 dB), under noise and interference
uncertainty. This requirement makes spectrum sensing, a hard nut to crack. Another major issue in
detection is hidden node problem wherein the node in vicinity of primary transmitter also indicates
absence of the primary signal since it is hidden behind the large object. There are various algorithms
for detection viz. energy detection, matched filter detection, feature detection (cyclostationary
detection, eigen-value based detection etc.) These algorithms have limitations of complexity,
requirement of signal knowledge and detection performance. In this paper the performance of
eigenvalue based detection (EBD) method in presence of noise and low SNR of the received signal has
been evaluated for a single user.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A New Approach for Error Reduction in Localization for Wireless Sensor Networksidescitation
Localization is one of the most challenging and
important issues in wireless sensor networks (WSNs),
especially if cost effective approaches are demanded. Distance
measurement based on RSSI (Received Signal Strength
Indication) is a low cost and low complexity of the distance
measurement technique, and it is widely applied in the range-
based localization of the WSN. The RSS (Received Signal
Strength) used to estimate the distance between an unknown
node and a number of reference nodes with known co-ordinates.
Location of the target node is then determined by trilateration.
Log-normal shadowing model, can better describe the
relationship between the RSSI value and distance. Non-line
of sight and multipath transmission effects as the indoor
environment, the distance error or ranging error is large. In
this paper, experimental results that are carried out to analyze
the sensitivity of RSSI measurements in an indoor
environment for various power levels are presented. Location
error influenced by distance measure error and network
connectivity is analyzed.
Index Terms—
TARGET LOCALIZATION IN WIRELESS SENSOR NETWORKS BASED ON RECEIVED SIGNAL STRE...sipij
We consider the problem of localizing a target taking the help of a set of anchor beacon nodes. A small
number of beacon nodes are deployed at known locations in the area. The target can detect a beacon
provided it happens to lie within the beacon’s transmission range. Thus, the target obtains a measurement
vector containing the readings of the beacons: ‘1’ corresponding to a beacon if it is able to detect the
target, and ‘0’ if the beacon is not able to detect the target. The goal is twofold: to determine the location
of the target based on the binary measurement vector at the target; and to study the behaviour of the
localization uncertainty as a function of the beacon transmission range (sensing radius) and the number of
beacons deployed. Beacon transmission range means signal strength of the beacon to transmit and receive
the signals which is called as Received Signal Strength (RSS). To localize the target, we propose a gridmapping
based approach, where the readings corresponding to locations on a grid overlaid on the region
of interest are used to localize the target. To study the behaviour of the localization uncertainty as a
function of the sensing radius and number of beacons, extensive simulations and numerical experiments
are carried out. The results provide insights into the importance of optimally setting the sensing radius and
the improvement obtainable with increasing number of beacons.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Enhanced signal detection slgorithm using trained neural network for cognitiv...IJECEIAES
Over the past few years, Cognitive Radio has become an important research area in the field of wireless communications. It can play an important role in dynamic spectrum management and interference identification. There are many spectrum sensing techniques proposed in literature for cognitive radio, but all those techniques detect only presence or absence of the primary user in the designated band and do not give any information about the used modulation scheme. In certain applications, in cognitive radio receiver, it is necessary to identify the modulation type of the signal so that the receiver parameters can be adjusted accordingly. Most of the modulated signals exhibit the property of Cyclostationarity that can be used for the purpose of correct detection of primary user and the modulation type. In this paper, we have proposed an enhanced signal detection algorithm for cognitive radio receiver which makes use of cyclostationarity property of the modulated signal to exactly detect, the modulation type of the received signal using a trained neural network. The algorithm gives better accuracy of signal detection even in low SNR conditions. The use of a trained neural network makes it more flexible and extendible for future applications
CODE AWARE DYNAMIC SOURCE ROUTING FOR DISTRIBUTED SENSOR NETWORKIJNSA Journal
Sensor network facilitates monitoring and controlling of physical environments. These wireless networks consist of dense collection of sensors capable of collection and dissemination of data. They have application in variety of fields such as military purposes, environment monitoring etc. Typical deployment of sensor network assumes central processing station or a gateway to which all other nodes route their data using dynamic source routing (DSR). This causes congestion at central station and thus reduces the efficiency of the network. In this work we will propose a better dynamic source routing technique using network coding to reduce total number of transmission in sensor networks resulting in better efficiency.
Performance Analysis of Group-Blind Multiuser Detectors for Synchronous CDMAidescitation
Blind multiuser detectors are attractive for the
suppression of interference in a CDMA environment. This
paper deals with the performance of group blind multiuser
detector for synchronous CDMA is analyzed. The blind multi
user detectors are Direct Matrix Inversion(DMI),Subspace
and group blind multiuser detector. The performance
analysis is performed by means of the Signal to Interference
Noise Ratio(SINR) and Bit Error Rate(BER). The numerical
results are plotted as variation of SINR Vs SNR, K and M,
SINR with respect to correlation coefficient( ) and BER
Vs Number of samples(M) for three detectors using
MATLAB software. The gain rises in group blind multiuser
detector over the DMI and subspace detectors. The
comparison is carried out for equicorrelated signals for
mathematical simplicity.
Signal Processing Algorithm of Space Time Coded Waveforms for Coherent MIMO R...IJMER
ABSTRACT: Space-time coding (STC) has been shown to play a key role in the design of MIMO radars with closely
spaced antennas. Multiple-input–multiple-output (MIMO) radar is emerging technology for target detection, parameter
identification, and target classification due to diversity of waveform and perspective. First, it turns out that a joint waveform
optimization problem can be decoupled into a set of individual waveform design problems. Second, a number of mono-static
waveforms can be directly used in a MIMO radar system, which offers flexibility in waveform selection. We provide
conditions for the elimination of waveform cross correlation. However, the mutual interference among the waveforms may
lead to performance degradation in resolving spatially close returns. We consider the use of space–time coding (STC) to
mitigate the waveform cross-correlation effects in MIMO radar. In addition, we also extend the model to partial waveform
cross-correlation removal based on waveform set division. Numerical results demonstrate the effectiveness of STC in MIMO
radar for waveform de-correlation. This paper introduces the signal processing issued for the coherent MIMO radar without
and with STC waveforms and also studied signal processing algorithms of coherent MIMO radar with STC waveforms for
improvement of target detection and recognition performance for real life scenario.
Keywords: STC, coherent, Probability detection, MIMO and SNR.
In this paper, we consider the joint optimal sensing
and distributed MAC protocol design for cognitive radio
networks. Specifically, we design a synchronized MAC protocol
for dynamic spectrum sharing among multiple secondary
users, which incorporates spectrum sensing for protecting active
primary users. We perform saturation throughput analysis for
the proposed MAC protocol that explicitly captures spectrum
sensing performance. Then, we find its optimal configuration
by formulating a throughput maximization problem subject to
detection probability constraints for primary users. In particular,
the optimal solution of this optimization problem returns the
required sensing time for primary users’ protection and optimal
contention window for maximizing total throughput of the
secondary network. Finally, numerical results are presented to
illustrate a significant performance gain of the optimal sensing
and protocol configuration.
Performance Evaluation of DV-HOP and Amorphous Algorithms based on Localizati...TELKOMNIKA JOURNAL
In the field of high-risk observation, the nodes in Wireless Sensor Network (WSN) are distributed
randomly. The result from sensing becomes meaningless if it is not known from where the originating node
is. Therefore, a sensor node positioning scheme, known as the localization scheme, is required. The
localization scheme consists of distance estimation and position computing. Thus, this research used
connectivity as distance estimation within range free algorithm DV-Hop and Amorphous, and then trilateral
algorithm for computing the position. Besides that, distance estimation using the connectivity between
nodes is not needed for the additional hardware ranging as required by a range-based localization
scheme. In this research compared the localization algorithm based on range free localization, which are
DV-Hop algorithm and Amorphous algorithm. The simulation result shows that the amorphous alg orithm
have achieved 13.60% and 24.538% lower than dv-hop algorithm for each parameter error localization and
energy consumption. On node density variations, dv-hop algorithm gained a localization error that is
26.95% lower than amorphous algorithm, but for energy consumption parameter, amorphous gained
14.227% lower than dv-hop algorithm. In the communication range variation scenario, dv-hop algorithm
gained a localization error that is50.282% lower than amorphous. However, for energy consumption
parameter, amorphous algorithm gained 12.35%. lower than dv-hop algorithm.
An efficient ant optimized multipath routing in wireless sensor networkEditor Jacotech
Today, the Wireless Sensor Network is increasingly gaining popularity and importance. It is the more interesting and stimulating area of research. Now, the WSN is applied in object tracking and environmental monitoring applications. This paper presents the self-optimized model of multipath routing algorithm for WSN which considers definite parameters like delay, throughput level and loss and generates the outcomes that maximizes data throughput rate and minimizes delay and loss. This algorithm is based on ANT optimization technique that will bring out an optimal and organized route for WSN and is also to avoid congestion in WSN, the algorithm incorporate multipath capability..
Cooperative Spectrum Sensing Technique Based on Blind Detection MethodINFOGAIN PUBLICATION
Spectrum sensing is a key task for cognitive radio. Our motivation is to increase the probability of detection of spectrum sensing in cognitive radio. The spectrum-sensing algorithms are proposed based on the statistical methods like EVD,CVD of a covariance matrix. In this Two test statistics are then extracted from the sample covariance matrix. The decision on the signal presence is made by comparing the two test statistics.The Detection probability and the associated threshold are found based on the statistical theory. In this paper, we study the collaborative sensing as a means to improve the performance of the proposed spectrum sensing technique and show their effect on cooperative cognitive radio network. Simulations results and performances evaluation are done in Matlab and the results are tabulated.
Blind Audio Source Separation (Bass): An Unsuperwised Approach IJEEE
Audio processing is an area where signal separation is considered as a fascinating works, potentially offering a vivid range of new scope and experience in professional and personal context. The objective of Blind Audio Source Separation is to separate audio signals from multiple independent sources in an unknown mixing environment. This paper addresses the key challenges in BASS and unsupervised approaches to counter these challenges. Comparative performance analysis of Fast-ICA algorithm and Convex Divergence ICA for Blind Source Separation is presented with the help of experimental result. Result reflects Convex Divergence ICA with α=-1 gives more accurate estimate in comparison of Fast ICA..
Secure data storage over distributed nodes in network through broadcast techn...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Ballpark Figure Algorithms for Data Broadcast in Wireless NetworksEditor IJCATR
In wireless system allocation is a necessary purpose and show industry expensive dependability in message protocol design. In multihop wireless networks, equally, imposition by a node by reason of immediate transmissions as its neighbors makes it nontrivial to graph a minimum-latency transmit algorithm, which is known to be NP-complete. A simple ballpark figure algorithm for the one-to-all transmit problem that improves all previously documented guarantees for this problem. In All-to-all transmit problem where every node sends its own consequence to all complementary nodes. In the all-to-all transmit problem, we current two algorithms with ballpark figure ratios of 20 and 34, civilizing the greatest result. A communication wants to be transmitted establishment its resource to all the previous nodes in the network. There may be different messages to be broadcasted from several sources. Two or more nodes broadcast a communication to an ordinary neighbor at the same time; the frequent node will not collect any of this communication. We say that collide has occurred at the ordinary node. So any message protocol for wireless networks must dispute with the distress of difficulty in the wireless intermediate.
AN EFFICIENT MATHEMATICAL MODELING FOR THE COMPREHENSIVE DESIGN OF AON INCLUD...optljjournal
This paper recommends a systematic wavelength assignment scheme which deliberately enhance the quality of service by minimizing the average dispersion in optical network. In this approach assignment of the wavelength recommended that allocates the wavelength as per mathematical model based on the path length request. Results validate that path length-based scheme improves the system performance in comparison with the commonly used existing assignment technique which works on the principle of first fit wavelength assignment(FFWA) and former assignment methodology should be ideal choice when the number of connection requests extremely high.
A novel scheme to improve the spectrum sensing performanceIJCNCJournal
Due to limited availability of spectrum for license
d users only, the need for secondary access by unli
censed
users is increasing. Cognitive radio turns out to b
e helping this situation because all that is needed
is a
technique that could efficiently detect the empty s
paces and provide them to the secondary devices wit
hout
causing any interference to the primary (licensed)
users. Spectrum sensing is the foremost function of
the
cognitive radio which senses the environment for wh
ite spaces. Energy detection is one of the various
spectrum sensing techniques that are under research
. Earlier it was shown that energy detection works
better under AWGN channel as compared to Rayleigh c
hannel, however the conventional spectrum sensing
techniques have a high probability of false alarm a
nd also show a better probability of detection for
higher
values of SNR. There is a need for a new technique
that shows a reduced probability of false alarm as
well
as an increase in the probability of detection for
lower values of SNR. In the present work the conven
tional
energy detection technique has been enhanced to get
better results.
Performance Analysis of Noise Uncertainty in Energy Detection Spectrum Sensin...Onyebuchi nosiri
Abstract—The Performance of Energy Detection (ED) spectrum sensing technique depends on threshold selected for deciding the presence or absence of Primary User. In practice, noise density is uncertain and can affect the performance of ED in that sometimes presence of signals is confused for their absence (noise) and vice versa. The traditional energy detection algorithm was based on fixed threshold and has been observed to be inefficient under noise uncertainty. The technique requires optimizing the threshold to be more flexible to check the noise uncertainty effects. The paper therefore proposed an algorithm relative to a unique environment which in effect considered the dynamism relatively and dependent on the environment. The results obtained demonstrated significant improvement compared to the traditional energy detection system
TARGET LOCALIZATION IN WIRELESS SENSOR NETWORKS BASED ON RECEIVED SIGNAL STRE...sipij
We consider the problem of localizing a target taking the help of a set of anchor beacon nodes. A small
number of beacon nodes are deployed at known locations in the area. The target can detect a beacon
provided it happens to lie within the beacon’s transmission range. Thus, the target obtains a measurement
vector containing the readings of the beacons: ‘1’ corresponding to a beacon if it is able to detect the
target, and ‘0’ if the beacon is not able to detect the target. The goal is twofold: to determine the location
of the target based on the binary measurement vector at the target; and to study the behaviour of the
localization uncertainty as a function of the beacon transmission range (sensing radius) and the number of
beacons deployed. Beacon transmission range means signal strength of the beacon to transmit and receive
the signals which is called as Received Signal Strength (RSS). To localize the target, we propose a gridmapping
based approach, where the readings corresponding to locations on a grid overlaid on the region
of interest are used to localize the target. To study the behaviour of the localization uncertainty as a
function of the sensing radius and number of beacons, extensive simulations and numerical experiments
are carried out. The results provide insights into the importance of optimally setting the sensing radius and
the improvement obtainable with increasing number of beacons.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Enhanced signal detection slgorithm using trained neural network for cognitiv...IJECEIAES
Over the past few years, Cognitive Radio has become an important research area in the field of wireless communications. It can play an important role in dynamic spectrum management and interference identification. There are many spectrum sensing techniques proposed in literature for cognitive radio, but all those techniques detect only presence or absence of the primary user in the designated band and do not give any information about the used modulation scheme. In certain applications, in cognitive radio receiver, it is necessary to identify the modulation type of the signal so that the receiver parameters can be adjusted accordingly. Most of the modulated signals exhibit the property of Cyclostationarity that can be used for the purpose of correct detection of primary user and the modulation type. In this paper, we have proposed an enhanced signal detection algorithm for cognitive radio receiver which makes use of cyclostationarity property of the modulated signal to exactly detect, the modulation type of the received signal using a trained neural network. The algorithm gives better accuracy of signal detection even in low SNR conditions. The use of a trained neural network makes it more flexible and extendible for future applications
CODE AWARE DYNAMIC SOURCE ROUTING FOR DISTRIBUTED SENSOR NETWORKIJNSA Journal
Sensor network facilitates monitoring and controlling of physical environments. These wireless networks consist of dense collection of sensors capable of collection and dissemination of data. They have application in variety of fields such as military purposes, environment monitoring etc. Typical deployment of sensor network assumes central processing station or a gateway to which all other nodes route their data using dynamic source routing (DSR). This causes congestion at central station and thus reduces the efficiency of the network. In this work we will propose a better dynamic source routing technique using network coding to reduce total number of transmission in sensor networks resulting in better efficiency.
Performance Analysis of Group-Blind Multiuser Detectors for Synchronous CDMAidescitation
Blind multiuser detectors are attractive for the
suppression of interference in a CDMA environment. This
paper deals with the performance of group blind multiuser
detector for synchronous CDMA is analyzed. The blind multi
user detectors are Direct Matrix Inversion(DMI),Subspace
and group blind multiuser detector. The performance
analysis is performed by means of the Signal to Interference
Noise Ratio(SINR) and Bit Error Rate(BER). The numerical
results are plotted as variation of SINR Vs SNR, K and M,
SINR with respect to correlation coefficient( ) and BER
Vs Number of samples(M) for three detectors using
MATLAB software. The gain rises in group blind multiuser
detector over the DMI and subspace detectors. The
comparison is carried out for equicorrelated signals for
mathematical simplicity.
Signal Processing Algorithm of Space Time Coded Waveforms for Coherent MIMO R...IJMER
ABSTRACT: Space-time coding (STC) has been shown to play a key role in the design of MIMO radars with closely
spaced antennas. Multiple-input–multiple-output (MIMO) radar is emerging technology for target detection, parameter
identification, and target classification due to diversity of waveform and perspective. First, it turns out that a joint waveform
optimization problem can be decoupled into a set of individual waveform design problems. Second, a number of mono-static
waveforms can be directly used in a MIMO radar system, which offers flexibility in waveform selection. We provide
conditions for the elimination of waveform cross correlation. However, the mutual interference among the waveforms may
lead to performance degradation in resolving spatially close returns. We consider the use of space–time coding (STC) to
mitigate the waveform cross-correlation effects in MIMO radar. In addition, we also extend the model to partial waveform
cross-correlation removal based on waveform set division. Numerical results demonstrate the effectiveness of STC in MIMO
radar for waveform de-correlation. This paper introduces the signal processing issued for the coherent MIMO radar without
and with STC waveforms and also studied signal processing algorithms of coherent MIMO radar with STC waveforms for
improvement of target detection and recognition performance for real life scenario.
Keywords: STC, coherent, Probability detection, MIMO and SNR.
In this paper, we consider the joint optimal sensing
and distributed MAC protocol design for cognitive radio
networks. Specifically, we design a synchronized MAC protocol
for dynamic spectrum sharing among multiple secondary
users, which incorporates spectrum sensing for protecting active
primary users. We perform saturation throughput analysis for
the proposed MAC protocol that explicitly captures spectrum
sensing performance. Then, we find its optimal configuration
by formulating a throughput maximization problem subject to
detection probability constraints for primary users. In particular,
the optimal solution of this optimization problem returns the
required sensing time for primary users’ protection and optimal
contention window for maximizing total throughput of the
secondary network. Finally, numerical results are presented to
illustrate a significant performance gain of the optimal sensing
and protocol configuration.
Performance Evaluation of DV-HOP and Amorphous Algorithms based on Localizati...TELKOMNIKA JOURNAL
In the field of high-risk observation, the nodes in Wireless Sensor Network (WSN) are distributed
randomly. The result from sensing becomes meaningless if it is not known from where the originating node
is. Therefore, a sensor node positioning scheme, known as the localization scheme, is required. The
localization scheme consists of distance estimation and position computing. Thus, this research used
connectivity as distance estimation within range free algorithm DV-Hop and Amorphous, and then trilateral
algorithm for computing the position. Besides that, distance estimation using the connectivity between
nodes is not needed for the additional hardware ranging as required by a range-based localization
scheme. In this research compared the localization algorithm based on range free localization, which are
DV-Hop algorithm and Amorphous algorithm. The simulation result shows that the amorphous alg orithm
have achieved 13.60% and 24.538% lower than dv-hop algorithm for each parameter error localization and
energy consumption. On node density variations, dv-hop algorithm gained a localization error that is
26.95% lower than amorphous algorithm, but for energy consumption parameter, amorphous gained
14.227% lower than dv-hop algorithm. In the communication range variation scenario, dv-hop algorithm
gained a localization error that is50.282% lower than amorphous. However, for energy consumption
parameter, amorphous algorithm gained 12.35%. lower than dv-hop algorithm.
An efficient ant optimized multipath routing in wireless sensor networkEditor Jacotech
Today, the Wireless Sensor Network is increasingly gaining popularity and importance. It is the more interesting and stimulating area of research. Now, the WSN is applied in object tracking and environmental monitoring applications. This paper presents the self-optimized model of multipath routing algorithm for WSN which considers definite parameters like delay, throughput level and loss and generates the outcomes that maximizes data throughput rate and minimizes delay and loss. This algorithm is based on ANT optimization technique that will bring out an optimal and organized route for WSN and is also to avoid congestion in WSN, the algorithm incorporate multipath capability..
Cooperative Spectrum Sensing Technique Based on Blind Detection MethodINFOGAIN PUBLICATION
Spectrum sensing is a key task for cognitive radio. Our motivation is to increase the probability of detection of spectrum sensing in cognitive radio. The spectrum-sensing algorithms are proposed based on the statistical methods like EVD,CVD of a covariance matrix. In this Two test statistics are then extracted from the sample covariance matrix. The decision on the signal presence is made by comparing the two test statistics.The Detection probability and the associated threshold are found based on the statistical theory. In this paper, we study the collaborative sensing as a means to improve the performance of the proposed spectrum sensing technique and show their effect on cooperative cognitive radio network. Simulations results and performances evaluation are done in Matlab and the results are tabulated.
Blind Audio Source Separation (Bass): An Unsuperwised Approach IJEEE
Audio processing is an area where signal separation is considered as a fascinating works, potentially offering a vivid range of new scope and experience in professional and personal context. The objective of Blind Audio Source Separation is to separate audio signals from multiple independent sources in an unknown mixing environment. This paper addresses the key challenges in BASS and unsupervised approaches to counter these challenges. Comparative performance analysis of Fast-ICA algorithm and Convex Divergence ICA for Blind Source Separation is presented with the help of experimental result. Result reflects Convex Divergence ICA with α=-1 gives more accurate estimate in comparison of Fast ICA..
Secure data storage over distributed nodes in network through broadcast techn...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Ballpark Figure Algorithms for Data Broadcast in Wireless NetworksEditor IJCATR
In wireless system allocation is a necessary purpose and show industry expensive dependability in message protocol design. In multihop wireless networks, equally, imposition by a node by reason of immediate transmissions as its neighbors makes it nontrivial to graph a minimum-latency transmit algorithm, which is known to be NP-complete. A simple ballpark figure algorithm for the one-to-all transmit problem that improves all previously documented guarantees for this problem. In All-to-all transmit problem where every node sends its own consequence to all complementary nodes. In the all-to-all transmit problem, we current two algorithms with ballpark figure ratios of 20 and 34, civilizing the greatest result. A communication wants to be transmitted establishment its resource to all the previous nodes in the network. There may be different messages to be broadcasted from several sources. Two or more nodes broadcast a communication to an ordinary neighbor at the same time; the frequent node will not collect any of this communication. We say that collide has occurred at the ordinary node. So any message protocol for wireless networks must dispute with the distress of difficulty in the wireless intermediate.
AN EFFICIENT MATHEMATICAL MODELING FOR THE COMPREHENSIVE DESIGN OF AON INCLUD...optljjournal
This paper recommends a systematic wavelength assignment scheme which deliberately enhance the quality of service by minimizing the average dispersion in optical network. In this approach assignment of the wavelength recommended that allocates the wavelength as per mathematical model based on the path length request. Results validate that path length-based scheme improves the system performance in comparison with the commonly used existing assignment technique which works on the principle of first fit wavelength assignment(FFWA) and former assignment methodology should be ideal choice when the number of connection requests extremely high.
A novel scheme to improve the spectrum sensing performanceIJCNCJournal
Due to limited availability of spectrum for license
d users only, the need for secondary access by unli
censed
users is increasing. Cognitive radio turns out to b
e helping this situation because all that is needed
is a
technique that could efficiently detect the empty s
paces and provide them to the secondary devices wit
hout
causing any interference to the primary (licensed)
users. Spectrum sensing is the foremost function of
the
cognitive radio which senses the environment for wh
ite spaces. Energy detection is one of the various
spectrum sensing techniques that are under research
. Earlier it was shown that energy detection works
better under AWGN channel as compared to Rayleigh c
hannel, however the conventional spectrum sensing
techniques have a high probability of false alarm a
nd also show a better probability of detection for
higher
values of SNR. There is a need for a new technique
that shows a reduced probability of false alarm as
well
as an increase in the probability of detection for
lower values of SNR. In the present work the conven
tional
energy detection technique has been enhanced to get
better results.
Performance Analysis of Noise Uncertainty in Energy Detection Spectrum Sensin...Onyebuchi nosiri
Abstract—The Performance of Energy Detection (ED) spectrum sensing technique depends on threshold selected for deciding the presence or absence of Primary User. In practice, noise density is uncertain and can affect the performance of ED in that sometimes presence of signals is confused for their absence (noise) and vice versa. The traditional energy detection algorithm was based on fixed threshold and has been observed to be inefficient under noise uncertainty. The technique requires optimizing the threshold to be more flexible to check the noise uncertainty effects. The paper therefore proposed an algorithm relative to a unique environment which in effect considered the dynamism relatively and dependent on the environment. The results obtained demonstrated significant improvement compared to the traditional energy detection system
Performance Evaluation of Energy Detector Based Spectrum Sensing for Cognitiv...IJECEIAES
This paper presents the performance evaluation of the Energy Detector technique, which is one of the most popular Spectrum Sensing (SS) technique for Cognitive Radio (CR). SS is the ability to detect the presence of a Primary User (PU) (i.e. licensed user) in order to allow a Secondary User (SU) (i.e unlicensed user) to access PU’s frequency band using CR, so that the available frequency bands can be used efficiently. We used for implementation an Universal Software Radio Peripheral (USRP), which is the most used Software Defined Radio (SDR) device for research in wireless communications. Experimental measurements show that the Energy Detector can obtain good performances in low Signal to Noise Ratio (SNR) values. Furthermore, computer simulations using MATLAB are closer to those of USRP measurements.
Analysis and Comparison of Different Spectrum Sensing Technique for WLANijtsrd
This Paper explores basic two systems of spectrum sensing Cooperative System and Non Cooperative System. Non Cooperative System includes Energy detector, Match Filter and cyclostationary with a performance analysis of transmitter based detection. It also includes analysis of Match Filter and Cyclostationary under low and high SNR, validating the result and applied the technique for Wireless local Area Network WLAN . To identify the no. of detected signal, chi square equation has been solved and finds the threshold. It has been observed during analysis that energy rises at high SNR under AWGN and under high SNR no. of detected signal decreases gradually when the no. of sample increases. When no. of sample increases then the no. of detected signal increases. The results of the detection techniques are reliable in comparison. Energy detection provides good result under high SNR values. All of the simulation work is done in MATLAB software and finalized the best detection technique for spectrum sensing. Abrar Ahmed | Rashmi Raj "Analysis and Comparison of Different Spectrum Sensing Technique for WLAN" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29174.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/29174/analysis-and-comparison-of-different-spectrum-sensing-technique-for-wlan/abrar-ahmed
An Optimized Energy Detection Scheme For Spectrum Sensing In Cognitive RadioIJERD Editor
With rapid growth of wireless devices, the Scarcity of Spectrum resources arises ,due to the improper and inefficient usage of available spectrum band. This problem can be alleviated by Cognitive radio . The major function of the cognitive radio rely on efficient sensing of available spectrum and Spectrum sensing techniques have been used to enhance the detection performance. Among these techniques, Energy detection is considered to be the implemented in practice because of less complexity. In this paper we propose an Adaptive threshold scheme which improves the detection performance under low SNR region. In this paper, noise uncertainty factor is considered wherein the Probability of error is minimized in various SNR regions.
Performance Comparison of Energy Detection Based Spectrum Sensing for Cogniti...irjes
With the rapid deployment of new wireless devices and applications, the last decade has witnessed a growing
demand for wireless radio spectrum. However, the policy of fixed spectrum assignment produces a bottleneck for more
efficient spectrum utilization, such that a great portion of the licensed spectrum is severely under-utilized. So the concept of
cognitive radio was introduced to address this issue.The inefficient usage of the limited spectrum necessitates the
development of dynamic spectrum access techniques, where users who have no spectrum licenses, also known as secondary
users, are allowed to use the temporarily unused licensed spectrum. For this purpose we have to know the presence or
absence of primary users for spectrum usage. So spectrums sensing is one of the major requirements of cognitive radio.Many
spectrum sensing techniques have been developed to sense the presence or absence of a licensed user. This paper evaluates
the performance of the energy detection based spectrum sensing technique in noisy and fading environments.The
performance of the energy detection technique will be evaluated by use of Receiver Operating Characteristics (ROC) curves
over additive white Gaussian noise (AWGN) and fading channels.
Performance Analysis and Comparative Study of Cognitive Radio Spectrum Sensin...IOSR Journals
Abstract : In cognitive radio, spectrum sensing is an emergent technology to find available and unused spectrum for increasing spectrum utilization and to overcome spectrum scarcity problem without harmful interference to licensed users. Cooperative spectrum sensing is used to give reliable performance in terms of detection probability and false alarm probability as well as in order to reduce fading, noise and shadowing effects on cognitive radio users. In this paper according to detection performance and complexity various cooperative spectrum sensing schemes have been discussed. We have analyzed spectrum sensing with different fusion rules and their comparative behavior has also been studied. Furthermore, we introduced AND-OR fusion rules in 2-bit and 3-bit hard combination schemes. Keywords - Cognitive radio, cooperative spectrum sensing, energy detector, spectrum sensing, hard combination
Performance Analysis and Comparative Study of Cognitive Radio Spectrum Sensin...IOSR Journals
In cognitive radio, spectrum sensing is an emergent technology to find available and unused
spectrum for increasing spectrum utilization and to overcome spectrum scarcity problem without harmful
interference to licensed users. Cooperative spectrum sensing is used to give reliable performance in terms of
detection probability and false alarm probability as well as in order to reduce fading, noise and shadowing
effects on cognitive radio users. In this paper according to detection performance and complexity various
cooperative spectrum sensing schemes have been discussed. We have analyzed spectrum sensing with different fusion rules and their comparative behavior has also been studied. Furthermore, we introduced AND-OR fusion rules in 2-bit and 3-bit hard combination schemes
Performance analysis of cooperative spectrum sensing using double dynamic thr...IAESIJAI
Increased use of wireless technologies and in turn more utilization of available spectrum is subsequently leading to the increasing demand for wireless spectrum. This research work incorporates spectrum sensing detection consisting of a double dynamic threshold followed by cooperative type spectrum sensing. The performance has been analyzed using two modulation schemes, quadrature-amplitude-modulation (QAM) and binary-phase-shift-keying (BPSK). Improved probability of detection has been witnessed using the double dynamic threshold where a comparison of average values of local decision (LD) and the observed value of energy (EO) has been considered instead of using direct values of local decisions and
energy. Further, the probability-of-detection (𝑃𝑑) is found to be better with QAM as compared to the BPSK. From the results, it has been observed that the detection of primary users is also affected by the number of samples. The simulation environment considered for this work is MATLAB and the performance of cooperative spectrum sensing for 500 and 1000 samples with -9db and -12 SNR by considering different false alarm values i. e 0.1, 0.3 and 0.5 has been analyzed. The further scope shall be to enhance the primary user detection by considering different QAM schemes and different signal to noise ratio (SNRs).
Medium Access Probability of Cognitive Radio Network Under ECC-33/Hata-Okumur...ijceronline
Cognitive radio detects the presence or absence of Primary User (PU) in its sensing region to provide the free radio spectrum to its Secondary user (SU). It is widely accepted a SU is only allowed to access a network of PU when no PU of that network is accessing the network at that moment. Sometimes SU misjudges the presence of PU inside the sensing region though the PU is in transmitting mode outside the sensing region which is termed as spatial false alarm. The incorporation of spatial false alarm makes the task more difficult. Previous literature performs this task using Lee’s path loss model .In our paper we have considered ECC-33/ Hata-Okumura Extended Model for two frequencies 1900MHz and 2100MHz as its frequency range is up to 3.5 GHz and compare the performance using different fading channels such as Rayleigh, Nakagami-m, Normal or Gaussian, Weibull, MRC Rayleigh and Selection Combining Rayleigh.
An Approach to Spectrum Sensing in Cognitive Radio IOSR Journals
Recent research shows that more than 70% of the available spectrum is not utilized
efficiently. The bandwidth becomes expensive due to a shortage of frequencies. Therefore for efficient
utilization of spectrum, we need to sniff the spectrum to determine whether it is being used by primary user or
not. The term cognitive radio refers to the adoption of radio parameters using the sensed information
of the spectrum. There are various spectrum sensing techniques proposed in the literature but still there is
room for researchers in this field to explore more sophisticated approaches. There are three major
categories of spectrum sensing techniques; transmitter detection, receiver detection and interference
temperature detection. This thesis presents a survey of techniques suggested in the literature for
spectrum sensing with a performance analysis of transmitter-based detection techniques.
An Approach to Spectrum Sensing in Cognitive RadioIOSR Journals
Abstract: Recent research shows that more than 70% of the available spectrum is not utilized efficiently. The bandwidth becomes expensive due to a shortage of frequencies. Therefore for efficient utilization of spectrum, we need to sniff the spectrum to determine whether it is being used by primary user or not. The term cognitive radio refers to the adoption of radio parameters using the sensed information of the spectrum. There are various spectrum sensing techniques proposed in the literature but still there is room for researchers in this field to explore more sophisticated approaches. There are three major categories of spectrum sensing techniques; transmitter detection, receiver detection and interference temperature detection. This thesis presents a survey of techniques suggested in the literature for spectrum sensing with a performance analysis of transmitter-based detection techniques. Keywords— Include at least 5 keywords or phrases
A SURVEY ON DYNAMIC SPECTRUM ACCESS TECHNIQUES FOR COGNITIVE RADIOijngnjournal
Cognitive radio (CR) is a new paradigm that utilizes the available spectrum band. The key characteristic of CR system is to sense the electromagnetic environment to adapt their operation and dynamically vary its radio operating parameters. The technique of dynamically accessing the unused spectrum band is known as Dynamic Spectrum Access (DSA). The dynamic spectrum access technology helps to minimize unused spectrum bands. In this paper, main functions of Cognitive Radio (CR) i.e. spectrum sensing, spectrum management, spectrum mobility and spectrum sharing are discussed. Then DSA models are discussed along with different methods of DSA such as Command and Control, Exclusive-Use, Shared Use of Primary Licensed User and Commons method. Game-theoretic approach using Bertrand game model, Markovian Queuing Model for spectrum allocation in centralized architecture and Fuzzy logic based method are also discussed and result are shown.
Similar to Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for Cognitive Radio Networks (20)
Integration of Unified Power Quality Controller with DGIJRST Journal
This paper gives an insight into the analytical results of the intergration of Unified power quality controller (conditioner) with distribution generation system. The intergration is achieved by connecting the DClink throught rectifier to the distribution generatoion along with thwe connection of the series and shunt inverter to the same dc link. This type of connection can account for the voltage sag, voltage swell, along with the reduction of harmonics and also compensation of reactive power. The analysis is supported with the simulation which will are discussed in detail in the paper.
An Efficient User Privacy and Protecting Location Content in Location Based S...IJRST Journal
In location-based query a user wants to query a database of location data, known as Points Of Interest (POIs), and does not want to reveal his/her location to the server due to privacy concerns; (ii) the owner of the location data, that is, the location server, do Abstract: Nowadays, it is very easy for a person to learn his/her location with the help of a Global Positioning System (GPS) enabled device. A location s not want to simply distribute its data to all users. The location server desires to have some control over its data, since the data is its asset. A major enhancement upon previous solutions by introducing a two stage approach, the first step is based on Oblivious Transfer using homomorphic encryption and the second step is based on Private Information Retrieval, to achieve a secure solution for both parties. Introduce a security model and analyse the security in the context of our protocol. To highlight a security weakness of our previous work and present a solution using efficient homomorphic system.
A Particle Swarm Optimization for Optimal Reactive Power DispatchIJRST Journal
This paper presents particle swarm optimization (PSO) based approach for solving optimal reactive power dispatch for minimizing power losses. The control variables are bus voltage magnitudes (continuous type), transformer tap settings (discrete type) and reactive power generation of capacitor banks (discrete type). The algorithm solution of PSO is tested on a standard IEEE 30 Bus system. The intention is to minimize power losses by optimizing the reactive power dispatch with optimal setting of control variables without violating inequality constraints and satisfying equality constraint. The detailed results for different cases have been listed
A Novel Approach for Interference Suppression Using a Improved LMS Based Adap...IJRST Journal
A novel adaptive beam forming technique is proposed for wireless communication applications based on the minimum bit error rate (MBER) criterion known as LMS algorithm. LMS (Least Mean Square) algorithm is used for steering the antenna beam electronically. Using the Rectangular, Hamming, Kaiser, Chebyshev windows both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed. By making use of window techniques half power beam width of an antenna is enhanced using Matlab simulation. The gain of the system will definitely improve the performance of CDMA based system, where the number of interferes is quite large and helps to increase the spectral efficiency of wireless communication systems. Any beam former that can depress the large number of interferers will improve the capacity and performance. Such beam formers are called smart antennas. They improve signal to interference ratio (SIR) of the communication system efficiently by forming narrow beam towards desired user and low side towards undesired users. Smart antennas offer a broad range of ways to improve wireless system performance.
Support Vector Machine for Wind Speed PredictionIJRST Journal
The energy is a vital input for the social and economic development of any nation. With increasing agricultural and industrial activities in the country, the demand for energy is also increasing. The increasing use of natural and renewable energy sources is needed to take the burden of our current dependency on fossil fuels. Development and analysis of renewable energy models helps utility in energy forecasting, planning, research and policy making. The wind power is a clean, inexhaustible, and almost a free source of energy. But the integration of wind parks with the power grid has resulted in many challenges for the utility in terms of commitment and control of power plants. As wind speed and wind direction fluctuate frequently, the accurate long-term and short-term forecasting of wind speed is important for ascertaining the wind power generation availability. To deal with wind speed forecasting, many methods have been developed such as physical method, which use lots of physical considerations to reach the best forecasting precision and other is the statistical method, which specializes in finding the relationship of the measured power data. Wind speed can be predicted by using time series analysis, artificial neural network, Kalman Filter method, linear prediction method, spatial correlation models and wavelet, also by using the support vector machines. In this paper, the SVM is used for day ahead prediction of wind speed using historical data of wind park. In this paper Support Vector Machine (SVM) results are compared with feedforward Backpropagation neural network. It is observed that the Mean Absolute Percentage Error (MAPE) by SVM method is around 7% and correlation coefficient is close to 1. This justifies the ability of SVM for wind speed prediction task than Backpropagation algorithm.
The Internet of Things (IoT), also referred to as the Internet of Objects, will change everything—including ourselves. This may seem like a bold statement, but consider the impact the Internet already had on education, science, communication, business, government, and humanity. Clearly, the Internet is one of the most important and a powerful creation in all of human history. This paper discussesIOT architecture, IOT applications and limitations of IOT.
Reduction of Frequency offset Using Joint Clock for OFDM Based Cellular Syste...IJRST Journal
This project addresses the problem of clock synchronization between a base station (BS) and a mobile station (MS). A conventional technique for clock synchronization is that the MS clock is derived from the downlink signal originated from a base station. In cellular systems, a base station and mobile stations need to be synchronized before data exchange. Since the base station clock reference is more accurate, a mobile station typically derives its clock reference from the base station. But the carrier frequency offset due to Doppler shift may have harmful effects on the local clock derivation. This project proposes a joint clock and frequency synchronization technique between a base station and a mobile station, which is effective even with Doppler shift. We derive the joint estimation algorithm by analyzing the phase and the amplitude distortion caused by the sampling frequency offset and the carrier frequency offset. Simulation results showing the effectiveness of the proposed algorithm will also be presented.
Analysis of Voltage and Current Variations in Hybrid Power SystemIJRST Journal
In this paper, a detailed dynamic model and simulation of a solar cell/wind turbine/fuel cell hybrid power system is Developed using a novel topology to complement each other and to alleviate the effects of environmental variations. Comparing with the nuclear energy and thermal power, the renewable energy is inexhaustible and has non-pollution Characteristics. Here Ultra-capacitors are used in power applications requiring short duration peak power. The voltage variation at the output is found to be within the acceptable range. The output fluctuations of the wind turbine varying with wind speed and the solar cell varying with both environmental temperature and sun radiation are reduced using a fuel cell. Therefore, this system can tolerate the rapid changes in load and environmental conditions, and suppress the effects of these fluctuations on the equipment side voltage. The proposed system can be used for off-grid power generation in non interconnected areas or remote isolated communities. Modeling and simulations are conducted using MATLAB/Simulink software packages to verify the effectiveness of the proposed system. The results show that the proposed hybrid power system can tolerate the rapid changes in natural conditions and suppress the effects of these fluctuations on the voltage within the acceptable range.
DTC Scheme for a Four-Switch Inverter-Fed PMBLDC Motor Emulating the Six-Swit...IJRST Journal
The paper deals with the direct torque control (DTC) of brushless DC (BLDC) motor drives fed by four-switch three phase inverters (FSTPI) rather than six-switch inverters (SSTPI) in conventional drives. For any three phase inverter require six switches, but these switches are reduced to four. This reduction of power switches from six to four improves the reliability of the inverter, size of the inverter is reduced and cost of the inverter is also reduces. The FSTPI could be regarded as a reconfigured topology of the SSTPI in case of a switch/leg failure which represents a crucial reliability benefit for many applications especially in electric and hybrid propulsion systems. The DTC of FSTPI-fed BLDC motor drives is treated considering two strategies, such as: 1) DTC-1: a strategy inspired from the one intended to SSTPI-fed BLDC motor drives; 2) DTC-2: a strategy that considers a dedicated vector selection subtable in order to independently control the torques developed by the phases connected to the FSTPI legs during their simultaneous conduction. The operational principle of the four-switch BLDC motor drive and the developed control scheme are theoretically analyzed and the performance is demonstrated by simulation.
NEUTRON STARS - UNIQUE COMPACT OBJECTS OF THEIR OWNIJRST Journal
This paper outlines the study of neutron stars right from the early
theoretical predictions and observations by various astrophysicists which
gradually aroused huge interests among the scientific community, to the
latest developments in the scientific analysis of the behavior of the different
categories of compact objects. Although white dwarfs, neutron stars, brown
dwarfs, Black Holes etc.fall under the category of compact objects, each of
them is unique in its own way.
A Compact Remote Switching With Efficient Monitoring For AC PlantsIJRST Journal
Remote monitoring has been implemented in many areas. This paper
introduces its specific application to air-conditioning plant control and
monitoring using PIC Microcontroller. Remote monitoring and intelligent
maintenance is one of the most important criteria for maximizing production
and process plant availability. Initially switching and monitoring were done
through manually and the control switches and level monitoring unit were
placed at separate places. Due to this, we cannot monitor all units at a time. In
our proposed system, remote switching and monitoring is done in the control
room itself. Majority of industries use distributed control system for high
reliability, improve response time, improved operator interface to plant,
improved accessibility of plant data.
Reactive Power Compensation in Distribution Network with Slide Mode MPPT Cont...IJRST Journal
The Grid connected PV system requires a proper voltage control controller.
In this paper an efficient voltage control by using slide mode controller with
Maximum Power Point Tracking (MPPT) is presented. The voltage
command is determined by the PV panel. Here the sliding mode controller is
designed so as to balance the power flow from PV panel to the grid and load
such that the PV power is utilized effectively. The design and simulation
using MATLAB is presented in this work.
Power Quality Improvement by UPQC based on Voltage Source ConvertersIJRST Journal
In modern power system consists of wide range of electrical, electronic and power electronic equipment in commercial and industrial applications. Since most of the electronic equipment’s are nonlinear in nature these will induce harmonics in the system, which affect the sensitive loads to be fed from the system. These problems are partially solved with the help of LC passive filters. However, this kind of filter cannot solve random variation in the load current wave form and voltage wave form. Active filters can resolve this problem. However, the cost of active filters is high. They are difficult to implement in large scale. Additionally, they also present lower efficiency than shunt passive filters. One of the many solutions is the use of a combined system of shunt and active series filters like Unified Power Quality Conditioner (UPQC) which aims at achieving a low cost under highly effective control. The UPQC device combines a shunt active filter together with a series active filter in a back-to-back configuration, to simultaneously compensate the supply voltage and the load current or to mitigate any type of voltage and current fluctuations and power factor correction in a power distribution network, such that improved power quality can be made available at the point of common coupling. The control strategies are modeled using MATLAB/SIMULINK. The performance is also observed under influence of utility side disturbances such as harmonics and voltage sags. The simulation results are compared without and with UPQC for the verification of results.
Detection of DNA Damage Using Comet Assay Image AnalysisIJRST Journal
Reactive species such as free radicals are constantly produced in vivo and DNA is the very important target of oxidative stress. Oxidative DNA damage is considered as a predictive biomarker to monitor the risk of development of many diseases. The comet assay is widely used for specifying oxidative DNA damage at a single cell level. The analysis of comet assay output images, however, poses considerable challenges. The comet assay, also known as single-cell gel electrophoresis (SCGE), is a simple, sensitive and reliable method for studying DNA damage caused by physical and chemical agents. So the comet assay is a well-established, simple, versatile, visual, rapid, and sensitive method used extensively to assess DNA damage quantitatively and qualitatively at single cell level. The comet assay is most frequently used to analyze white blood cells or lymphocytes in human bio monitoring studies. So through the analysis of comet assay image we can detect edge of damaged DNA comet isolating it from undamaged DNA.
Review of Step down Converter with Efficient ZVS OperationIJRST Journal
This paper presents the review of step down converter with efficient ZVS operation. The designed buck converter uses ZCS technique and the function is realized so that the power form is converted from 12V DC 5V DC (1A). A detailed analysis of zero current switching buck converters is performed and a mathematical analysis of the mode of operation is also presented. In order to reduce the switching losses in associated with conventional converters; resonant inductor and resonant capacitor (LC resonant circuit) is applied which helps to turn on-off the switch at zero current. The dc-dc buck converter receives the energy from the input source, when the switch is turned-on. The buck–buck converters have characteristics that warrant a more detailed study. The buck converters under discontinuous conduction mode /continuous conduction mode boundary.
Review of Reduction of Leakage Current in Cascaded Multilevel InverterIJRST Journal
Multilevel inverters are a source of high power, often used in industrial applications and can use either sine or modified sine waves. A multilevel inverter uses a series of semiconductor power converters (usually two to three) thus generating higher voltage. Reverse leakage current in a semiconductor device is the current from that semiconductor device when the device is reverse biased. In earlier method transformer is used for generating multilevel output and grid synchronization. Transformer increases the leakage current. Now transformerless method and sine modulation techniques are presented to reduce the leakage current.
A Study of SEPIC Converter Based Fuzzy Logic Controller For Hybrid SystemIJRST Journal
This paper presents the study of integrated hybrid renewable energy system. The wind and solar are used as input sources for the hybrid system. The proposed system involves the design of photovoltaic (PV) and wind energy conversion system (WECS).The system is designed for constant wind speed and varying solar irradiation and insolation. Maximum power point tracking (MPPT) algorithm is used to extract the maximum power from PV array. The integration of two input sources is done by single-ended primary-inductor converter. Fuzzy logic controller is used to control the duty cycle of one of the converter switch thereby extracting the maximum power from solar array. The system consists of photovoltaic (PV) array, wind energy conversion system (WECS), single-ended primary-inductor converter, voltage source inverter (VSI), LC filter and three phase load.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
2. International Journal of Research in Science & Technology
Volume 2 | Issue 4 | April 2015 | ISSN: 2349-0845
Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for
Cognitive Radio Networks
Page 14
I. INTRODUCTION
What has motivated cognitive radio technology, an
emerging novel concept in wireless access, is spectral
usage experiments done by FCC. These experiments show
that at any given time and location, much of the licensed
(pre-allocated) spectrum(between 80% and 90%) is idle
because licensed users (termed primary users) rarely utilize
all the assigned frequency bands at all time. Such
unutilized bands are called spectrum holes, resulting in
spectral inefficiency. These experiments suggest that the
spectrum scarcity is caused by poor spectrum management
rather than a true scarcity of usable frequency[1]. The key
features of a cognitive radio transceiver are radio
environment awareness and spectrum intelligence.
Intelligence can be achieved through learning the spectrum
environment and adapting transmission parameters [2,3].
The dynamic spectrum access (DSA) allows the
operating spectrum of a radio network to be selected
dynamically from the available spectrum. DSA is applied
in cognitive radio networks, which has a hierarchical
access structure with primary and secondary users as
shown in Fig. 1 The basic idea of DSA is to open licensed
spectrum to secondary users (which are unlicensed users)
while limiting the interference received by primary users
(which are licensed users)[2,3,4]. This allows secondary
users to operate in the best available channel
opportunistically. Therefore, DSA requires opportunistic
spectrum sharing, which is implemented via two strategies
Figure 1: A basic cognitive radio network architecture.
A. Spectrum Sensing
The purpose of spectrum sensing is to identify the
spectrum holes for opportunistic spectrum access [4, 5].
After available channels (spectrum holes) are detected
successfully, they may be used for communications by a
secondary transmitter and a secondary receiver. Spectrum
sensing is performed based on the received signal from the
primary users. Primary users have two states, idle or
active. With the presence of the noise, primary signal
detection at a secondary user can be viewed as a binary
hypothesis testing problem in which Hypothesis 0 (H0) and
Hypothesis 1 (H1)are the primary signal absence and the
primary signal presence, respectively .Based on the
hypothesis testing model, several spectrum sensing
techniques have been developed[6].
B. Over View of the Paper:
In section 2 we discuss the previous work methods and
drawbacks, in section 3 we discuss proposed work, in that
basic system model and computationally efficient energy
detection (CE-ED) techniques were evaluated by use of
Receiver Operating Characteristics (ROC) curves over
additive white Gaussian noise (AWGN) and fading
(Rayleigh & Nakagami-m) channels. Results show that for
single user detection, the energy detection technique
performs better in AWGN channel than in the fading
channel models. The performance of cooperative detection
is better than single user detection in fading environments.
In section we discuss the results and Conclusions and
along with Future work.
II. PROPOSED SPECTRUM SENSING DETECTION
TECHNIQUE
A. System Model of Spectrum Sensing
Primary users are in either idle state or active state.
With the presence of the noise, the signal detection at the
receiver can be viewed as a binary hypothesis testing
problem[8] in which Hypothesis 0 (H0) and Hypothesis 1
(H1) are the primary signal absence and the primary signal
presence, respectively. The nth, n = 1, 2……….., sample
of the received signal, y(n), can be given under the binary
hypothesis as :
0
1
:
:
w n H
y n
x n w n H
(1)
where x = hs.
The complex signal, s has real component sr and imaginary
component si, i.e., s = sr+jsi.
The AWGN samples are assumed to be circularly
symmetric complex Gaussian (CSCG) random variables
with mean zero (E{w(n)} = 0) and variance
2 2
2 Var 2w ww n where E{·} and Var{·} stand
for mean and variance, respectively,
i.e., 2
~ 0,2 ww n CN . A noise sample is denoted as
w(n) =wr(n)+jwi(n) where wr(n) and wi(n) are real-valued
Gaussian random variables with mean zero and variance
2
w , i.e., wr(n) , wi(n)~ 2
0, wN . The channel gain is
denoted as h = hr+ jhi. The channel gain can be assumed
as a constant within each spectrum sensing period and
can be writtenas
y(n) = θx(n) + w(n) (2)
where θ = 0 for 0H and θ = 1 for 1H .
3. International Journal of Research in Science & Technology
Volume 2 | Issue 4 | April 2015 | ISSN: 2349-0845
Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for
Cognitive Radio Networks
Page 15
i. Improved energy detection under low SNR
model:
Three signal models, S1, S2 and S3 which are given
and can be considered in the energy detection. For S1 and
S2 signal models, the distribution of Λ is modeled exactly
Under H0, the false-alarm probability is with the upper
incomplete Gamma function. Under H1, the detection
probabilities are with the Marcum-Q function and with the
upper incomplete Gamma function for S1 and S2,
respectively. However, none of these functions have
closed-form inverse functions, and thus there is no closed-
form expression for the detection threshold λ when a false-
alarm or detection probability is given even with AWGN
channel[9,11]. This problem becomes more complicated
when the fading effect is considered. Although there are
rigorous expressions for the average detection performance
over some particular fading channels in the literature, such
expressions may not help for the parameter optimization
(e.g., optimizing detection threshold). Since S1 and S2
signal models have different set of expressions, results of
one model cannot be derived from those of the other
model. Moreover, the distribution of Λ cannot be modeled
exactly for S3[11,12].
To solve all these problems, the CLT approach can be
used as a unified approach of accurately approximating the
distribution of Λ in the three signal models.The
distribution of Λ can be approximated as a normal
distribution for sufficiently large N as
22 2
0
22 2
1
2 22 2
1
2 , 2 :
2 1 , 2 1 2 : 1 3
2 1 , 2 1 : 2
w w
w w
w w
N N
N N with S or S
N N with S
N H
N H
N H
(3)
Under the low-SNR assumption . .; 1i e ,the
signal has little impact onthe variance of the test statistic
under 1H , as used in the Edell model, Berkeley model and
Torrieri model which are well-known Gaussian
approximations for the test statistic under 1H [12, 13].
Thus, (3) can be accurately approximated for any of the
three signal models as
2 4
0
2 4
1
, :
1 , :
low
N N
N N
N H
nN H
(4)
where 2 w . The false alarm probability
fP and the missed-detection probability mdP can be
evaluated as
2
2
1
2 2
f
N
P Erfc
N
(5)
And
2
2
11
1 ,
2 2
md
N
P Erfc
N
(6)
respectively, where where
1
2 2
z
Q z Erfc
and
Erfc(·) is the complementaryerror function defined as
22 t
z
Erfc z e dt
[4]. Since the detection
probability, 1d mdP P , relates to the
cumulative distribution function (CDF)of the test statistic.
The ROC curve, AUC, and the total error
rate are used as the performance measures. The ROC curve
is a measurement for the sensitivity of a detector used in a
binary classifier system [12]. In signal-detection theory,
the ROC (or the complementary ROC) curve is a graphical
plot of d mdP or P versus fP as the
discrimination threshold λ varies. The ROC curves of
spectrum-sensing detectors have highly non-linear
behavior, and they are, in general, convex[9,10,11]. In
wireless communications, dP depends on the
received instantaneous SNR, which is a function of the
mobile radio channel gain. Therefore, the average
detection probability (or average missed-detection
probability) over fading channels is important for plotting
the ROC curve.
ii. Logical Selective method based on Fusion
center
Performance of an energy detector used for
cooperative spectrum sensing is investigated. Single
cooperative node, multiple cooperative nodes and multi-
hop cooperative Sensing networks are considered. Two
fusion strategies, data fusion and decision fusion, are
analyzed. For data fusion, upper bounds for average
detection probabilities are derived. For decision fusion, the
detection and false alarm probabilities are derived under
the out-of generalized “k- -n” fusion rule at the fusion
center by considering errors in the reporting
channel[10,11]
4. International Journal of Research in Science & Technology
Volume 2 | Issue 4 | April 2015 | ISSN: 2349-0845
Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for
Cognitive Radio Networks
Page 16
In decision fusion, each cooperative node makes one-
bit hard decision on the primary user activity: „0‟ and „1‟
mean the absence and presence of primary activities,
respectively. Then, each reporting channel is with a narrow
bandwidth. Capability of complex signal processing is
needed at each cooperative node. The fusion rule at the
fusion center can be OR, AND, or Majority rule, which
can be generalized as the “k-out-of-n” rule. The decision
device of the fusion center with n cooperative nodes can be
implemented with the k-out-of-n rule in which the fusion
center decides the presence of primary activity if there are
k or more cooperative nodes that individually decide on the
presence of primary activity[8,9]. When k = 1, k = n and,
/ 2k n where . is the ceiling function, the k-out-of-
n rule represents OR rule, AND rule and Majority rule,
respectively.
It is assumed that the decision device of
the fusion center is implemented with the k out- of-n rule
(i.e., the fusion center decides the presence of primary
activity if there are k or more cooperative nodes that
individually decide the presence of primary activity).
When k = 1, k = n and / 2k n , the k-out-of-n rule
represents OR rule, AND rule and Majority rule,
respectively. In the following, for simplicity of
presentation, fp and dp are used to represent false alarm
and detection probabilities, respectively, for a cooperative
node, and use fp and dp to represent false alarm and
detection probabilities, respectively, in the fusion center.
iii. Improved sub nyquist sampling method for
spectrum sensing
The received signal x(t) is assumed to be an analog
wideband sparse spectrum signal, band limited to [0,Bmax].
Denote the Fourier transform of x(t) by X(f). Depending
on the application, the entire frequency band is segmented
into L narrowband channels, each of them with bandwidth
B, such that Bmax = L × B. It is assumed that the signal
bands are uncorrelated with each other. The channels are
indexed from 0 to L − 1. Those spectral bands which
contain part of the signal spectrum are termed active
channels, and the remaining bands are called vacant
channels[11,12]. Denote the number of such active
channels by N. The indices of the N active channels are
collected into a vector
b=[b1, b2,.. . , bN] (7)
which is referred to as the active channel set.
In the considered system, N and b are unknown. However,
we know the maximum channel occupancy which is
defined as
max
max
N
L
(8)
where Nmax ≥ N is the maximum possible number of
occupied channels. Figure 1 depicts the spectrum of a
multiband signal at the sensing radio, which contains L =
32 channels, each with a bandwidth of B = 10 MHz. The
signal is present in N = 6 channels, and the active channel
set is b [8].
The problem is, given Bmax, B and Ω max, to find the
presence or absence of the signal in each spectral band or
equivalently find the active channel set, b, at a sub-Nyquist
sample rate.
Figure 3. Proposed wideband spectrum sensing model.
The proposed model for wideband spectrum sensing
is illustrated in Figure 3. The analog received signal at the
sensing cognitive radio is sampled by the multicoset
sampler at a sample rate lower than the Nyquist rate. The
sampling reduction ratio is affected by the channel
occupancy and multicoset sampling parameters. The
outputs of the multicoset sampler are partially shifted
using a multirate system, which contains the interpolation,
delaying and down sampling stages. Next, the sample
correlation matrix is computed from the finite number of
obtained data. Finally, the correlation matrix is
investigated to discover the position of the active channels
by subspace methods [9, 10, 12].
III. RESULTS AND CONCLUSION
A. Improved CE-ED METHOD
Fig 4:Probability of false Vs Probability of Detection
As the probabilty of false alarm increases the probability
of detection also increases
5. International Journal of Research in Science & Technology
Volume 2 | Issue 4 | April 2015 | ISSN: 2349-0845
Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for
Cognitive Radio Networks
Page 17
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Probability Of False Alarm
ProbabilityOfMissDetection
ROC plot for Probability of False Alarm vs Probability of Miss Detection for SNR = -10 dB
Simulation
Theory
Fig 5:Probability of false Vs Probability of Miss detection
As the probability of false alarm increases the probability
of miss detection decreases
-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0
0.4
0.5
0.6
0.7
0.8
0.9
1
X: -11
Y: 0.8725
ROC curve for SNR vs Probability of Detection for Pf=0.2
Signal To Noise Ratio (dB)
ProbabilityOfDetection
Simulation
Theory
Fig 6:Probability of Detection Vs SNR
As probability of detection increases SNR also increases
B. Logical Selective Method:
Fig 7: Spectrum sensing with AND rule
The PM (increased detection performance) rapidly
improves with increasing average SNR.
Improved sequential Forward search Method:
1 2 3 4 5 6 7
0
0.5
1
1.5
Eigenvalues
i
i
0 2 4 6 8 10 12 14 16 18 20
0
50
100
150
200
250
300
350
400
k, spectral index
P
MU
(k)
0 2 4 6 8 10 12 14 16 18 20
0
20
40
f
X(f)
S=[4 5 10 11 16 17]
0 200 400 600 800 1000 1200
0
1
2
3
t
L=22 p=7 MSE=3.8365%
0 2 4 6 8 10 12 14 16 18 20
0
100
200
300
400
k, spectral index
P
MU
(k) 0 2 4 6 8 10 12 14 16 18 20
0
10
20
30
40
50
frequency
|X(f)|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
0 20 40
0
0.5
1
1.5
2
time
|x(t)|
0 20 40
0
0.5
1
1.5
2
time
|xr
(t)|
0 5 10 15 20
0
10
20
30
40
50
frequency
|X(f)|
0 5 10 15 20
0
10
20
30
40
50
frequency
|Xr
(f)|
Fig 8: Performance of wideband spectrum sensing under sub
nyquist sampling method
Several significant values correspond to active
channels are appeared where their locations specify the
estimated active channel set. The other channels are
interpreted as the vacant channels and can be used by the
cognitive system to transmit.The results show that even in
low SNR with taking enough number of samples a perfect
detection is possible.
In the standardization process of vehicular networks,
channel models are required to evaluate and select the
proposed physical layer modulation and coding schemes.
Analytical and simulation results are provided to support
the theoretical formulations and derivations. The presented
results show that spectrum sensing and access in vehicular
communication can be improved by modeling the wireless
environment precisely. IN a cognitive radio network
(CRN), in-band spectrum sensing is essential for the
protection of legacy spectrum users, with which the
presence of primary users (PUs) can be detected promptly,
allowing secondary users (SUs) to vacate the channels
immediately. For in-band sensing, it is important to meet
the detectability requirements, such as the maximum
allowed latency of detection (e.g., 2 seconds in IEEE
6. International Journal of Research in Science & Technology
Volume 2 | Issue 4 | April 2015 | ISSN: 2349-0845
Performance Evaluation of Computationally Efficient Energy Detection Based Spectrum Sensing for
Cognitive Radio Networks
Page 18
802.22) and the probability of misdetection and false-
alarm. From the presented result it is clear that a channel
model composed of mixed distributions is useful for
designing vehicular wireless. We studied
the performance of cooperative spectrum sensing and
signal detection base on hard decision combining
technique in data fusion centre compared with non-
cooperative one.
In cooperative technique, OR and AND rules are
employed and evaluate the system performance by using
probability of detection (Pd) and SNR as metric. The OR
rule decides H1 when at least one CR user forward bit-1
while the AND rule decides H1 when all CR users forward
their bit-1 to data fusion centre. The numerical results
show that cooperative technique has better performance
compared with non cooperative one and employing OR
rule can improve probability of detection than AND rule
and non cooperative signal detection at different SNR
values. Cooperative technique is more effective when
received SNR in cognitive radio users is low due to fading
and shadowing. Noncooperative technique achieves the
same detection probability value (optimal value) as
cooperative technique when received SNR is greater than
10 dB, Furthermore, a minimum of 15 collaborated users
relatively in cognitive radio system can achieve optimal
value of detection probability. However, it depends on the
threshold value used in signal detection.
IV. FUTURE WORK
In future, we would like to explore other types of feature
detection and evaluate their performance comparatively
with energy detection. In-band sensing of wireless micro-
phones should be another subject of our future work.
REFERENCES
[1] Y. Ma, D. I. Kim, and Zhiqiang Wu, “Optimization of
OFDMA-Based Cellular Cognitive Radio Networks,”
IEEE Trans. Commun., vol. 58, no. 8, Aug. 2010, pp.
2265–76.
[2] H. Bezabih et al., “Digital Broadcasting: Increasing
the Available White Space Spectrum Using TV
Receiver Information,” IEEE Vehic. Tech. Mag., vol.
7 no. 1, Mar. 2012, pp. 24–30.
[3] Y.-J. Choi and K. G. Shin, “Opportunistic Access of
TV Spectrum Using Cognitive-Radio-Enabled
Cellular Networks,” IEEE Trans. Vehic. Tech., vol.
60, no. 8, Oct. 2011.
[4] A. Goldsmith et al., “Breaking Spectrum Gridlock
with Cognitive Radios: An Information Theoretic
Perspective,” Proc. IEEE, vol. 97, no. 5, May 2009,
pp. 894–914.
[5] S. Srinivasa and S. A. Jafar, “The Throughput
Potential of Cognitive Radio: A Theoretical
Perspective,” ACSSC ‟06, Oct.–Nov. 2006, pp. 221–
25.
[6] M. Fitch et al., “Wireless Service Provision in TV
White Space with Cognitive Radio Technology: A
Telecom Operator‟s Perspective and Experience,”
IEEE Commun. Mag., vol. 49, no. 3, Mar. 2011, pp.
64–73.
[7] IEEE Std 802.16TM-2005, “IEEE Standard for Local
and Metropolitan Area Networks Part 16: Air
Interface for Fixed and Mobile Broadband Wireless
Access Systems.”
[8] IEEE Std 802.11n TM-2009, “IEEE Standard for
Information Technology-Telecommunications and
Information Exchange between Systems-Local and
Metropolitan Area Networks-Specific Requirements
Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer Specifications.”
[9] ETSI, “Digital Video Broadcasting (DVB); Framing
Structure,Channel Coding and Modulation for Digital
Terrestrial Television,” EN 300 744 V1.2.1, July
1999.
[10]ETSI, “Digital Video Broadcasting (DVB); Frame
Structure Channel Coding and Modulation for A
Second Generation Digital Terrestrial Television
Broadcasting System (DVB-T2),” Draft ETSI EN 302
755 V1.1.1 (2008-04), 2008.
[11]J. D. Poston and W. D. Horne, “Discontiguous OFDM
Considerations for Dynamic Spectrum Access in Idle
TV Channels,” Proc. IEEE Int‟l. Symp. New Frontiers
Dynamic Spectr. Access Networks, vol. 1, Baltimore,
MD, Nov. 2005, pp. 607–10.
[12]C. Hausl and J. Hagenauer, “Relay Communication
with Hierarchical Modulation,” IEEE Commun.
Letters, vol. 11, no. 1, Jan. 2007, pp. 64–66.
[13]Annex I, DVB-T2 standard v1.3.1.