The document summarizes a study on simulating a cognitive radio system using different wireless channel models. The study evaluated the performance of an energy detector for spectrum sensing in the cognitive radio system. Three channel models were considered: (1) Additive White Gaussian Noise channel, (2) Rayleigh fading channel, and (3) Rician fading channel. The simulation results showed that the detection capability of the energy detector improved with increasing signal-to-noise ratio, and the probabilities of false alarm and missed detection decreased. The Rician fading model, which includes a line-of-sight path, had a significant impact on energy detector performance compared to the other models.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
MM-PNEMO: a mathematical model to assess handoff delay and packet lossjournalBEEI
Wireless networks incorporate Mobile Nodes (MNs) that use wireless access networks to communicate. However, the communication among these MNs are not remained stable due to the poor network coverage during inter mobility. Moreover, the wireless nodes are typically small that results in resource-constrained. Thus, it is uphill to use algorithms having giant processing power or memory footprint. Accordingly, it is essential to check schemes consistently to evaluate the performance within the probable application scenario. To do so, numerical analysis could be a notable method to grasp the performance of mobility management schemes as well as the constraint of evolving mobility management solutions specifically for multi-interfaced MR in Proxy NEMO environment. This paper analyzes handoff performance by using a mathematical model of Multihoming-based scheme to support Mobility management in Proxy NEMO (MM-PNEMO) environment. Moreover, a comparative study has been made among the standard Network Mobility Basic Support Protocol (NEMO BSP), Proxy NEMO (PNEMO) and MM-PNEMO scheme respectively. The performance metrics estimated for these schemes are mainly handoff delay and packet loss. This paper also analysed the packet loss ratio and handoff gain as a function of cell radius, number of SMR and velocity respectively. It is apparent that, the MM-PNEMO scheme shows lower packet loss ratio (1%) compared to NEMO-BSP (11%) and P-NEMO (6%).
Combining SFBC_OFDM Systems with SVD Assisted Multiuser Transmitter and Multi...IOSR Journals
Abstract: In this work, we exploit the SVD assisted multiuser transmitter (MUT) and multiuser detector (MUD) technique, using downlink (DL) preprocessing transmitter and DL postprocessing receiver matrice .In combination with space frequency block coding (SFBC). And also propose the precoded DL transmission scheme, were the both proposed schemes take advantage of the channel state information (CSI) of all users at the base station (BS), but only of the mobile station (MS)’s own CSI, to decompose the MU MIMO channels into parallel single input single output (SISO), these two proposed schemes are compared to the vertical layered space time (V_BLAST) combined with SFBC (SFBC_VBLAST). Our Simulation results show that the performance of the proposed scheme with DL Zero Forcing (ZF) transmitter for interference canceller outperforms the SFBC_VBLAST and the precoded DL schemes with ZF receiver in frequency selective fading channels. Keywords – Post processing, Preprocessing,, SFBC, SVD, ZF.
BER ANALYSIS FOR DOWNLINK MIMO-NOMA SYSTEMS OVER RAYLEIGH FADING CHANNELSIJCNCJournal
The Multiple-input multiple-output (MIMO) technique combined with non-orthogonal multiple access (NOMA) has been considered to enhance total system performance. This paper studies the bit error rate of two-user power-domain NOMA systems using successive interference cancellation receivers, with zeroforcing equalization over quasi-static Rayleigh fading channels. Successive interference cancellation technique at NOMA receivers has been the popular research topic due to its simple implementation, despite its vulnerability to error propagation. Closed-form expressions are derived for downlink NOMA in single-input single-output and uncorrelated quasi-static MIMO Rayleigh fading channel. Analytical results are consolidated with Monte Carlo simulation.
A Potent MIMO–OFDM System Designed for Optimum BER and its Performance Anal...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
An RSS Based Localization Algorithm in Cellular NetworksIDES Editor
Localization in cellular networks has attracted
significant interest in responding to localization accuracy
driven by the emergency services (U.S. Enhanced 911) and the
security applications. This study focuses on the Mobile Station
(MS) localization employing the measurements of the detected
Base Stations (BSs) Received Signal Strength (RSS). A
localization algorithm based only on measurements of BS
RSS and BS basic information is proposed. Experimental
results are presented illustrating the performance of the
proposed localization algorithm in a dense multipath
environment with uneven geographical area.
Effect on Channel Capacity of Multi-User MIMO System in Crowded AreaIJEEE
Multiple-Input Multiple-Output (MIMO) and Multi-User
MIMO (MU-MIMO) systems have been expected to
improve the channel capacity over a limited bandwidth of
existing networks.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
1. Explain the difference between a side channel and a covert channel. Discuss the claim that every side channel can be converted to a covert channel and vice versa.
2. Explain the difference between intrusion prevention and intrusion detection systems. Discuss the implications of
the base-rate fallacy for intrusion prevention.
3. Consider the concept of “continuous” enforcement in UCON. Discuss how this concept might be implemented in
practice. Develop your answer in context of specific application contexts.
On the development of methodology for planning and cost modeling of a wide ar...IJCNCJournal
The most important stages in designing a
computer
network
in a
wider geographical area include:
definition of requirements, topological description
,
identification and calculation of relevant parameters
(
i
.
e
.
traffic matrix
)
, determining the shortest path between nodes, quantification of the effect of various
levels
of technical and technological development of urban areas involved, the cost of technology
,
and the
cost of services. The
se
parameters differ for WAN networks in different regions
–
their calculation depends
directly
on
the data “
i
n the field
”
: number of inhabitants, distance between populated areas,
network
traffic
density
,
as well as
available
bandwidth
. The
main
reason for identification and evaluation of these
parameters
is
to develop a model that could
meet the
constraints
im
posed by poten
tial beneficiaries.
In this
paper
,
we develop a methodology for planning and cost
-
modeling of a wide area network
and
validate it
in
a case study,
under the
supposition
that
behavioral interactions of individuals and groups play a significant
role and have
to be taken into consideration
by employing either simple or composite indicators of
socioeconomic status
.
Framework for wireless network security using quantum cryptographyIJCNCJournal
Data that is transient over an unsecured wireless network is always susceptible to being intercepted by
anyone within the range of the wireless signal. Hence providing secure communication to keep the user’s
information and devices safe when connected wirelessly has become one of the major concerns. Quantum cryptography provides a solution towards absolute communication security over the network by encoding
information as polarized photons, which can be sent through the air. This paper explores on the aspect of
application of quantum cryptography in wireless networks.
In this paper we present a methodology for integrating quantum cryptography and security of IEEE 802.11 wireless networks in terms of distribution of the encryption keys.
MM-PNEMO: a mathematical model to assess handoff delay and packet lossjournalBEEI
Wireless networks incorporate Mobile Nodes (MNs) that use wireless access networks to communicate. However, the communication among these MNs are not remained stable due to the poor network coverage during inter mobility. Moreover, the wireless nodes are typically small that results in resource-constrained. Thus, it is uphill to use algorithms having giant processing power or memory footprint. Accordingly, it is essential to check schemes consistently to evaluate the performance within the probable application scenario. To do so, numerical analysis could be a notable method to grasp the performance of mobility management schemes as well as the constraint of evolving mobility management solutions specifically for multi-interfaced MR in Proxy NEMO environment. This paper analyzes handoff performance by using a mathematical model of Multihoming-based scheme to support Mobility management in Proxy NEMO (MM-PNEMO) environment. Moreover, a comparative study has been made among the standard Network Mobility Basic Support Protocol (NEMO BSP), Proxy NEMO (PNEMO) and MM-PNEMO scheme respectively. The performance metrics estimated for these schemes are mainly handoff delay and packet loss. This paper also analysed the packet loss ratio and handoff gain as a function of cell radius, number of SMR and velocity respectively. It is apparent that, the MM-PNEMO scheme shows lower packet loss ratio (1%) compared to NEMO-BSP (11%) and P-NEMO (6%).
Combining SFBC_OFDM Systems with SVD Assisted Multiuser Transmitter and Multi...IOSR Journals
Abstract: In this work, we exploit the SVD assisted multiuser transmitter (MUT) and multiuser detector (MUD) technique, using downlink (DL) preprocessing transmitter and DL postprocessing receiver matrice .In combination with space frequency block coding (SFBC). And also propose the precoded DL transmission scheme, were the both proposed schemes take advantage of the channel state information (CSI) of all users at the base station (BS), but only of the mobile station (MS)’s own CSI, to decompose the MU MIMO channels into parallel single input single output (SISO), these two proposed schemes are compared to the vertical layered space time (V_BLAST) combined with SFBC (SFBC_VBLAST). Our Simulation results show that the performance of the proposed scheme with DL Zero Forcing (ZF) transmitter for interference canceller outperforms the SFBC_VBLAST and the precoded DL schemes with ZF receiver in frequency selective fading channels. Keywords – Post processing, Preprocessing,, SFBC, SVD, ZF.
BER ANALYSIS FOR DOWNLINK MIMO-NOMA SYSTEMS OVER RAYLEIGH FADING CHANNELSIJCNCJournal
The Multiple-input multiple-output (MIMO) technique combined with non-orthogonal multiple access (NOMA) has been considered to enhance total system performance. This paper studies the bit error rate of two-user power-domain NOMA systems using successive interference cancellation receivers, with zeroforcing equalization over quasi-static Rayleigh fading channels. Successive interference cancellation technique at NOMA receivers has been the popular research topic due to its simple implementation, despite its vulnerability to error propagation. Closed-form expressions are derived for downlink NOMA in single-input single-output and uncorrelated quasi-static MIMO Rayleigh fading channel. Analytical results are consolidated with Monte Carlo simulation.
A Potent MIMO–OFDM System Designed for Optimum BER and its Performance Anal...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
An RSS Based Localization Algorithm in Cellular NetworksIDES Editor
Localization in cellular networks has attracted
significant interest in responding to localization accuracy
driven by the emergency services (U.S. Enhanced 911) and the
security applications. This study focuses on the Mobile Station
(MS) localization employing the measurements of the detected
Base Stations (BSs) Received Signal Strength (RSS). A
localization algorithm based only on measurements of BS
RSS and BS basic information is proposed. Experimental
results are presented illustrating the performance of the
proposed localization algorithm in a dense multipath
environment with uneven geographical area.
Effect on Channel Capacity of Multi-User MIMO System in Crowded AreaIJEEE
Multiple-Input Multiple-Output (MIMO) and Multi-User
MIMO (MU-MIMO) systems have been expected to
improve the channel capacity over a limited bandwidth of
existing networks.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
1. Explain the difference between a side channel and a covert channel. Discuss the claim that every side channel can be converted to a covert channel and vice versa.
2. Explain the difference between intrusion prevention and intrusion detection systems. Discuss the implications of
the base-rate fallacy for intrusion prevention.
3. Consider the concept of “continuous” enforcement in UCON. Discuss how this concept might be implemented in
practice. Develop your answer in context of specific application contexts.
On the development of methodology for planning and cost modeling of a wide ar...IJCNCJournal
The most important stages in designing a
computer
network
in a
wider geographical area include:
definition of requirements, topological description
,
identification and calculation of relevant parameters
(
i
.
e
.
traffic matrix
)
, determining the shortest path between nodes, quantification of the effect of various
levels
of technical and technological development of urban areas involved, the cost of technology
,
and the
cost of services. The
se
parameters differ for WAN networks in different regions
–
their calculation depends
directly
on
the data “
i
n the field
”
: number of inhabitants, distance between populated areas,
network
traffic
density
,
as well as
available
bandwidth
. The
main
reason for identification and evaluation of these
parameters
is
to develop a model that could
meet the
constraints
im
posed by poten
tial beneficiaries.
In this
paper
,
we develop a methodology for planning and cost
-
modeling of a wide area network
and
validate it
in
a case study,
under the
supposition
that
behavioral interactions of individuals and groups play a significant
role and have
to be taken into consideration
by employing either simple or composite indicators of
socioeconomic status
.
Framework for wireless network security using quantum cryptographyIJCNCJournal
Data that is transient over an unsecured wireless network is always susceptible to being intercepted by
anyone within the range of the wireless signal. Hence providing secure communication to keep the user’s
information and devices safe when connected wirelessly has become one of the major concerns. Quantum cryptography provides a solution towards absolute communication security over the network by encoding
information as polarized photons, which can be sent through the air. This paper explores on the aspect of
application of quantum cryptography in wireless networks.
In this paper we present a methodology for integrating quantum cryptography and security of IEEE 802.11 wireless networks in terms of distribution of the encryption keys.
A fuzzy logic controllerfora two link functional manipulatorIJCNCJournal
This paper presents a new approach for designing a Fuzzy Logic Controller "FLC"for a dynamically multivariable nonlinear coupling system. The conventional controller with constant gains for different operating points may not be sufficient to guarantee satisfactory performance for Robot manipulator. The Fuzzy Logic Controller utilizes the error and the change of error as fuzzy linguistic inputs to regulate the system performance. The proposed controller have been developed to simulate the dynamic behavior of A
Two-Link Functional Manipulator. The new controller uses only the available information of the input-output for controlling the position and velocity of the robot axes of the motion of the end effectors
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.
A review study of handover performance in mobile ipIJCNCJournal
The Mobile Internet Protocol (Mobile IP) is an extension to the Internet Protocol proposed by the Internet
Engineering Task Force (IETF) that addresses the mobility issues. In order to support un-interrupted
services and seamless mobility of nodes across the networks (and/or sub-networks) with permanent IP
addresses, handover is performed in mobile IP enabled networks. Handover in mobile IP is source cause of
performance degradation as it results in increased latency and packet loss during handover. Other issues
like scalability issues, ordered packet delivery issues, control plane management issues etc are also
adversely affected by it. The paper provides a constructive survey by classifying, discussing and comparing
different handover techniques that have been proposed so far, for enhancing the performance during
handovers. Finally some general solutions that have been used to solve handover related problems are
briefly discussed.
Key management in information centric networkingIJCNCJournal
Information centric networking (ICN) has been in the spotlight of recent research. It is an emerging
communication paradigm that relays on the concept of publish and subscribe. It aims to revise the current
Internet with a new clean slate architecture where the design is completely different from today’s location
based model. To secure the forwarding plan in this network, it is vital to have a time based transient
forwarding identifiers by periodically changing the network link identifiers. This assumes shared keys to be
distributed prior the communications between an entity termed topology manager (TM) and each forwarder
in the network. Exchanging and sharing a secret key between two parties is one of most critical functions in
cryptography that needs to be more concerned when integrating cryptographic functions into the system. As
ICN is brand new Internet architecture, many existing cryptography protocols may need to be redesigned
to fit this new architecture. Therefore, this paper focuses on the security aspect of ICN and proposes an
initial design to deploy the integrated Diffie-Hellman-DSA key exchange protocol as a key distributions
mechanism.
Different date block size using to evaluate the performance between different...IJCNCJournal
The different computer networks whether wired or wireless are becoming more popular with its high
security aspect. Different security algorithms and technique are using to avoid any aforementioned attacks.
One of these technique is a cryptography technique that makes the data as unreadable during the transfer
hence; there is no chance to reclaim the information. Presently, most of the users are using various media
types and internet to transfer the data but, it has the chance to retrieve the data by using these media types.
The perfect solution for this problem is to provide security on time-to-time basis; this stage is always
significant to the security related community discussions. This paper explains the comparison between the
run time of three different encryption algorithms which are DES, AES and Blowfish The compression
includes using different modes, data block size and different operation modes. As a result, Blowfish
algorithm followed by AES take less time for running compared to DES.
Further results on the joint time delay and frequency estimation without eige...IJCNCJournal
Joint Time Delay and Frequency Estimation (JTDFE) problem of complex sinusoidal signals received at
two separated sensors is an attractive problem that has been considered for several engineering
applications. In this paper, a high resolution null (noise) subspace method without eigenvalue
decomposition is proposed. The direct data Matrix is replaced by an upper triangular matrix obtained from
Rank-Revealing LU (RRLU) factorization. The RRLU provides accurate information about the rank and the
numerical null space which make it a valuable tool in numerical linear algebra.The proposed novel method
decreases the computational complexity of JTDFE approximately to the half compared with RRQR
methods. The proposed method generates estimates of the unknown parameters which are based on the
observation and/or covariance matrices. This leads to a significant improvement in the computational load.
Computer simulations are included in this paper to demonstrate the proposed method.
PAPR REDUCTION OF OFDM SIGNAL BY USING COMBINED HADAMARD AND MODIFIED MEU-LAW...IJCNCJournal
Orthogonal frequency division multiplexing (OFDM) is a technique which gives high quality of service (QOS) to the users by mitigating the fading signals as well as high data rates in multimedia services. However, the peak-to-average power ratio (PAPR) is a technical challenge that reduces the efficiency of RF power amplifiers. In this paper, we propose the combined Hadamard transform and modified meu-law companding transform method in order to lessen the effects of the peak-to-average power ratio of the
OFDM signal. Simulation results show that the proposed scheme reduces PAPR compared to other companding techniques as well as the Hadamard transform technique when used on its own.
Dcf learn and performance analysis of 802.11 b wireless networkIJCNCJournal
Though WLAN wireless network has been widely deployed as the main split-flow deployment of the
communication network, little study emphasizes its performance as WLAN protocols were only designed for
the public communicating conveniently with each other. Actually that too much wireless access points
assembling together will cause self-interference to the whole WLAN network. This paper investigates the
distributed coordination function (DCF) learn and the performance study of 802.11b networks. Firstly, our
study illustrates the performance of its MAC layer and its fairness issues related to DCF. Next we propose
the details which should be paid attention to in deploying network services. Then, performance analyses
are evaluated by simulation and real test for a dense wireless network. Our main goal is to give proposals
to network operators how to design a WLAN network more standardized and orderly.
LTE QOS DYNAMIC RESOURCE BLOCK ALLOCATION WITH POWER SOURCE LIMITATION AND QU...IJCNCJournal
3GPP has defined the long term evolution (LTE) for 3G radio access in order to maintain the future
competitiveness for 3G technology, the system provides the capability of supporting a mixture of services
with different quality of service (QoS) requirements. This paper proposes a new cross-layer scheduling
algorithm to satisfy better QoS parameters for real time applications. The proposed algorithm takes care of
allocating resource blocks (RBs) with different modulation and coding schemes (MCS) according to target
bit error rate (BER), user equipment supportable MCS, queue stability constraints and available transmit
power constraints. The proposed algorithm has been valued, compared with an earlier allocation algorithm
in terms of service rate and packet delay and showed better performance regards the real time
applications.
ETOR-Efficient Token based Opportunistic RoutingIJCNCJournal
This paper proposes an Efficient Token based Opportunistic Routing called ETOR, which is an
improvement to the token based coordination approach for opportunistic routing proposed by Economy[1].
In Economy, method used for finding the connected candidate order chooses neighbor as the next
candidate by considering ETX of that neighbor towards the source but it does not consider the link
probability between the relay candidate and neighbor to be selected. ETOR proposes variant methods for
finding the connected candidate order in token based opportunistic routing by considering both the ETX
of the neighbor towards source as well as ETX of the relay towards sending candidate which avoids weaker
links between its intermediate nodes thereby improving the throughput and reducing the AA Ratio. We also
propose a solution for reducing the number of hops traversed by the token, which in turn increases the
token generation speed. Simulation results show that the proposed ETOR approaches perform better than
Economy approach in terms of AA Ratio, number of hops traversed by the token and number of token
traversals.
Cryptography Scheme of an Optical Switching System Using Pico/Femto Second So...University of Malaya (UM)
We propose a system of microring resonators (MRRs) incorporating with an add/drop filter system. Optical soliton can be simulated and used to generate entangled photon, applicable in single and multiple optical switching. Chaotic signals can be generated via the MRRs system. Therefore continuous spatial and temporal signals are generated spreading over the spectrum. Polarized photons are formed incorporating the
polarization control unit into the MRRs, which allows different time slot entangled photons to be randomly formed. Results show the single soliton pulse of 0.7 ps where the multi soliton pulse with FSR and FWHM of 0.6 ns and 20 ps are generated using the add/drop filter system. Here Ultra-short single soliton pulse with FWHM=42 fs can be simulated. These pulses are providing required communication signals to generate pair of polarization entangled photons among different time frame where the polarization control unit and polarizer beam splitter (PBS) are connected to the ring resonator system.
Decimal Convertor Application for Optical Wireless Communication by Generatin...University of Malaya (UM)
Two systems consist of microring resonators (MRRs) and an add/drop filter are used to generate signals as localized multi wavelengths. Quantum dense encoding
can be performed by output signals of selected wavelengths incorporated to a polarization control system. Therefore dark and bright optical soliton pulses
with different time slot are generated. They can be converted into digital logic quantum codes using a decimal convertor system propagating along a wireless networks. Results show that multi soliton wavelength, ranged from 1.55 m to 1.56 m with FWHM and FSR of 10 pm and 600 pm can be generated respectively. Keywords- Micro Ring Resonator, Quantum Dense Coding (QDC), Wireless network communication system.
Improved performance of scs based spectrum sensing in cognitive radio using d...eSAT Journals
Abstract
Tremendous growth in current wireless networks raises the demand of more frequency spectrum, over the finite availability of spectrum resource. Although, the research has specifies that the available primary users (i.e. licensed user) has not occupying the channel all the time. The most effective technology known as Cognitive radio giving promises for a solution of under utilization of available frequency spectrum in wireless communication. In cognitive radio network two types of wireless user can be define as primary user and secondary user. Primary users have highest priority to utilize the available band of frequency and secondary user can utilize these services only when the channel is vacant by primary user and there will be no any interference. The optimization of this may be implemented by a smart technique such as cognitive radio, which is fully automated intelligent wireless sensor tool having capability to sense, learn & adjust relevant operating parameters dynamically in radio atmosphere. This can be happen if we prefer the appropriate window technique to evaluate system parameter for sensing the availability of vacant band. We show that by comparing the different windows techniques, cognitive radios not only provide better spectrum opportunity but also provide the chance to huge number of wireless users.
Keywords: Primary user, Secondary user, Spectrum Sensing and Window technique etc.
DUAL PORT COGNITIVE RADIO ANTENNA USING TUNABLE BAND PASS FILTERjmicro
In this paper a dual port microstrip antenna with tunable band pass filter is proposed for cognitive radio applications. In single port reconfigurable antennas for cognitive radio, sensing and communication is done simultaneously. This can lead to failure of real time communication, also it may induce interference to primary user, dual antenna system solves this problem. The proposed antenna consist of one UWB microstrip antenna for sensing the holes in spectrum and other is communication antenna. Communication antenna is made tunable by using varacter diode in ‘G’ shaped DMS(defected microstrip structure) filter integrated in feedline.The sensing antenna is having UWB bandwidth from 3.4 GHz to 13.2 GHz and efficiency of more than 80%. The narrowband antenna has dual and triple operating frequencies which is tunable in the range of 4-5 GHz, 6-10 GHz and 10-11 GHz according to the biasing of varacterdiode. This antenna as efficiency more than 70%.
Bit Error Rate Performance of MIMO Spatial Multiplexing with MPSK Modulation ...ijsrd.com
Wireless communication is one of the most effective areas of technology development of our time. Wireless communications today covers a very wide array of applications. In this, we study the performance of general MIMO system, the general V-BLAST architecture with MPSK Modulation in Rayleigh fading channels. Based on bit error rate, we show the performance of the 2x2 schemes with MPSK Modulation in noisy environment. We also show the bit error rate performance of 2x2, 3x3, 4x4 systems with BPSK modulation. We see that the bit error rate performance of 2x2 systems with QPSK modulation gives us the best performance among other schemes analysed here.
Frequency-Wavelength Trapping by Integrated Ring Resonators For Secured Netwo...University of Malaya (UM)
Optical pulse trapping via a series of microring resonator (MRR) is presented. Large bandwidth of optical soliton is generated by input pulse propagating within the MRRs. Distinguished discrete wavelength or frequency pulses can be generated by using localized spatial pulses via a networks communication system. Quantum codes can be generated by using a polarization control unit and a beam splitter, incorporating to the MRRs. Here frequency band of 10.7 MHz and 16 MHz and wavelengths of 206.9 nm, 1448 nm, 2169 nm and 2489 nm are localized and obtained and used for quantum codes generation applicable for secured networks communication.
Generation of Nanometer Optical Tweezers Used for Optical Communication Netw...University of Malaya (UM)
A system of Half-Panda microring resonator (MRR) is proposed to generate ultra-short nanometer (nm)
optical tweezers. The dark soliton propagates inside nonlinear MRR. Molecules or photons transport within the system when the dark soliton is used as input pulse. Nano optical tweezers can be generated and used to many applications in optical communication networks. Here the smallest nano optical tweezers signals with full width at half maximum (FWHM) of 9 nm is obtained where the free spectrum range (FSR) of 50 nm is simulated.
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.
Ultra-short Multi Soliton Generation for Application in Long Distance Commun...University of Malaya (UM)
Generation of picometer optical soliton pulses is investigated using a nonlinear PANDA ring resonator system connecting to an add/drop filter system. The objectives of the research are to employ systems of microring resonator (MRR) to generate binary signals to be carried out along fiber optic communication. Effective parameters such as refractive indices of a silicon waveguide, coupling coefficients (), coupling loss, radius of the ring (R) and the input power can be selected properly to operate the nonlinear behavior. The input Gaussian laser pulses with power of 600 mW are inserted into the system. The central wavelength of the input power has been selected to λ0=1.55 µm where the nonlinear refractive index of the medium is n2=2.6×10−17 m2 W−1. Therefore binary signals generated by the add/drop filter system can be converted to secure codes where the decoding process of the transmitted codes can be obtained at the final step. Here, multi soliton pulses with full width at half maximum (FWHM) of 325 could be generated, converted to secure codes and finally detected over 70 km optical fiber communication link.
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
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.
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.
Vehicle Ad Hoc Networks (VANETs) have become a viable technology to improve traffic flow and safety on the roads. Due to its effectiveness and scalability, the Wingsuit Search-based Optimised Link State Routing Protocol (WS-OLSR) is frequently used for data distribution in VANETs. However, the selection of MultiPoint Relays (MPRs) plays a pivotal role in WS-OLSR's performance. This paper presents an improved MPR selection algorithm tailored to WS-OLSR, designed to enhance the overall routing efficiency and reduce overhead. The analysis found that the current OLSR protocol has problems such as redundancy of HELLO and TC message packets or failure to update routing information in time, so a WS-OLSR routing protocol based on improved-MPR selection algorithm was proposed. Firstly, factors such as node mobility and link changes are comprehensively considered to reflect network topology changes, and the broadcast cycle of node HELLO messages is controlled through topology changes. Secondly, a new MPR selection algorithm is proposed, considering link stability issues and nodes. Finally, evaluate its effectiveness in terms of packet delivery ratio, end-to-end delay, and control message overhead. Simulation results demonstrate the superior performance of our improved MR selection algorithm when compared to traditional approaches.
A Novel Medium Access Control Strategy for Heterogeneous Traffic in Wireless ...IJCNCJournal
So far, Wireless Body Area Networks (WBANs) have played a pivotal role in driving the development of intelligent healthcare systems with broad applicability across various domains. Each WBAN consists of one or more types of sensors that can be embedded in clothing, attached directly to the body, or even implanted beneath an individual's skin. These sensors typically serve asingle application. However, the traffic generated by each sensor may have distinct requirements. This diversity necessitates a dual approach: tailored treatment based on the specific needs of each traffic typeand the fulfillment of application requirements, such asreliability and timeliness. Never the less, the presence of energy constraints and the unreliable nature of wireless communications make QoS provisioning under such networks a non-trivial task. In this context, the current paper introduces a novel Medium AccessControl (MAC) strategy for the regular traffic applications of WBANs, designed to significantly enhance efficiency when compared to the established MAC protocols IEEE 802.15.4 and IEEE 802.15.6, with a particular focus on improving reliability, timeliness, and energy efficiency.
May_2024 Top 10 Read Articles in Computer Networks & Communications.pdfIJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
A Topology Control Algorithm Taking into Account Energy and Quality of Transm...IJCNCJournal
The efficient use of energy in wireless sensor networks is critical for extending node lifetime. The network topology is one of the factors that have a significant impact on the energy usage at the nodes and the quality of transmission (QoT) in the network. We propose a topology control algorithm for software-defined wireless sensor networks (SDWSNs) in this paper. Our method is to formulate topology control algorithm as a nonlinear programming (NP) problem with the objective to optimizing two metrics, maximum communication range, and desired degree. This NP problem is solved at the SDWSN controller by employing the genetic algorithm (GA) to determine the best topology. The simulation results show that the proposed algorithm outperforms the MaxPower algorithm in terms of average node degree and energy expansion ratio.
Multi-Server user Authentication Scheme for Privacy Preservation with Fuzzy C...IJCNCJournal
The integration of artificial intelligence technology with a scalable Internet of Things (IoT) platform facilitates diverse smart communication services, allowing remote users to access services from anywhere at any time. The multi-server environment within IoT introduces a flexible security service model, enabling users to interact with any server through a single registration. To ensure secure and privacy preservation services for resources, an authentication scheme is essential. Zhao et al. recently introduced a user authentication scheme for the multi-server environment, utilizing passwords and smart cards, claiming resilience against well-known attacks. This paper conducts cryptanalysis on Zhao et al.'s scheme, focusing on denial of service and privacy attacks, revealing a lack of user-friendliness. Subsequently, we propose a new multi-server user authentication scheme for privacy preservation with fuzzy commitment over the IoT environment, addressing the shortcomings of Zhao et al.'s scheme. Formal security verification of the proposed scheme is conducted using the ProVerif simulation tool. Through both formal and informal security analyses, we demonstrate that the proposed scheme is resilient against various known attacks and those identified in Zhao et al.'s scheme.
Advanced Privacy Scheme to Improve Road Safety in Smart Transportation SystemsIJCNCJournal
In -Vehicle Ad-Hoc Network (VANET), vehicles continuously transmit and receive spatiotemporal data with neighboring vehicles, thereby establishing a comprehensive 360-degree traffic awareness system. Vehicular Network safety applications facilitate the transmission of messages between vehicles that are near each other, at regular intervals, enhancing drivers' contextual understanding of the driving environment and significantly improving traffic safety. Privacy schemes in VANETs are vital to safeguard vehicles’ identities and their associated owners or drivers. Privacy schemes prevent unauthorized parties from linking the vehicle's communications to a specific real-world identity by employing techniques such as pseudonyms, randomization, or cryptographic protocols. Nevertheless, these communications frequently contain important vehicle information that malevolent groups could use to Monitor the vehicle over a long period. The acquisition of this shared data has the potential to facilitate the reconstruction of vehicle trajectories, thereby posing a potential risk to the privacy of the driver. Addressing the critical challenge of developing effective and scalable privacy-preserving protocols for communication in vehicle networks is of the highest priority. These protocols aim to reduce the transmission of confidential data while ensuring the required level of communication. This paper aims to propose an Advanced Privacy Vehicle Scheme (APV) that periodically changes pseudonyms to protect vehicle identities and improve privacy. The APV scheme utilizes a concept called the silent period, which involves changing the pseudonym of a vehicle periodically based on the tracking of neighboring vehicles. The pseudonym is a temporary identifier that vehicles use to communicate with each other in a VANET. By changing the pseudonym regularly, the APV scheme makes it difficult for unauthorized entities to link a vehicle's communications to its real-world identity. The proposed APV is compared to the SLOW, RSP, CAPS, and CPN techniques. The data indicates that the efficiency of APV is a better improvement in privacy metrics. It is evident that the AVP offers enhanced safety for vehicles during transportation in the smart city.
April 2024 - Top 10 Read Articles in Computer Networks & CommunicationsIJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
DEF: Deep Ensemble Neural Network Classifier for Android Malware DetectionIJCNCJournal
Malware is one of the threats to security of computer networks and information systems. Since malware instances are available sufficiently, there is increased interest among researchers on usage of Artificial Intelligence (AI). Of late AI-enabled methods such as machine learning (ML) and deep learning paved way for solving many real-world problems. As it is a learning-based approach, accumulated training samples help in improving thequality of training and thus leveraging malware detection accuracy. Existing deep learning methods are focusing on learning-based malware detection systems. However, there is need for improving the state of the art through ensemble approach. Towards this end, in this paper we proposed a framework known as Deep Ensemble Framework (DEF) for automatic malware detection. The framework obtains features from training samples. From given malware instance a grayscale image is generated. There is another process to extract the opcode sequences. Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) techniques are used to obtain grayscale image and opcode sequence respectively. Afterwards, a stacking ensemble is employed in order to achieve efficient malware detection and classification. Malware samples collected fromthe Internet sources and Microsoft are used for theempirical study. An algorithm known as Ensemble Learning for Automatic Malware Detection (EL-AML) is proposed to realize our framework. Another algorithm named Pre-Process is proposed to assist the EL-AML algorithm for obtaining intermediate features required by CNN and LSTM.Empirical study reveals that our framework outperforms many existing methods in terms of speed-up and accuracy.
High Performance NMF Based Intrusion Detection System for Big Data IOT TrafficIJCNCJournal
With the emergence of smart devices and the Internet of Things (IoT), millions of users connected to the network produce massive network traffic datasets. These vast datasets of network traffic, Big Data are challenging to store, deal with and analyse using a single computer. In this paper we developed parallel implementation using a High Performance Computer (HPC) for the Non-Negative Matrix Factorization technique as an engine for an Intrusion Detection System (HPC-NMF-IDS). The large IoT traffic datasets of order of millions samples are distributed evenly on all the computing cores for both storage and speedup purpose. The distribution of computing tasks involved in the Matrix Factorization takes into account the reduction of the communication cost between the computing cores. The experiments we conducted on the proposed HPC-IDS-NMF give better results than the traditional ML-based intrusion detection systems. We could train the HPC model with datasets of one million samples in only 31 seconds instead of the 40 minutes using one processor), that is a speed up of 87 times. Moreover, we have got an excellent detection accuracy rate of 98% for KDD dataset.
A Novel Medium Access Control Strategy for Heterogeneous Traffic in Wireless ...IJCNCJournal
So far, Wireless Body Area Networks (WBANs) have played a pivotal role in driving the development of intelligent healthcare systems with broad applicability across various domains. Each WBAN consists of one or more types of sensors that can be embedded in clothing, attached directly to the body, or even implanted beneath an individual's skin. These sensors typically serve asingle application. However, the traffic generated by each sensor may have distinct requirements. This diversity necessitates a dual approach: tailored treatment based on the specific needs of each traffic typeand the fulfillment of application requirements, such asreliability and timeliness. Never the less, the presence of energy constraints and the unreliable nature of wireless communications make QoS provisioning under such networks a non-trivial task. In this context, the current paper introduces a novel Medium AccessControl (MAC) strategy for the regular traffic applications of WBANs, designed to significantly enhance efficiency when compared to the established MAC protocols IEEE 802.15.4 and IEEE 802.15.6, with a particular focus on improving reliability, timeliness, and energy efficiency.
A Topology Control Algorithm Taking into Account Energy and Quality of Transm...IJCNCJournal
The efficient use of energy in wireless sensor networks is critical for extending node lifetime. The network topology is one of the factors that have a significant impact on the energy usage at the nodes and the quality of transmission (QoT) in the network. We propose a topology control algorithm for software-defined wireless sensor networks (SDWSNs) in this paper. Our method is to formulate topology control algorithm as a nonlinear programming (NP) problem with the objective to optimizing two metrics, maximum communication range, and desired degree. This NP problem is solved at the SDWSN controller by employing the genetic algorithm (GA) to determine the best topology. The simulation results show that the proposed algorithm outperforms the MaxPower algorithm in terms of average node degree and energy expansion ratio.
Multi-Server user Authentication Scheme for Privacy Preservation with Fuzzy C...IJCNCJournal
The integration of artificial intelligence technology with a scalable Internet of Things (IoT) platform facilitates diverse smart communication services, allowing remote users to access services from anywhere at any time. The multi-server environment within IoT introduces a flexible security service model, enabling users to interact with any server through a single registration. To ensure secure and privacy preservation services for resources, an authentication scheme is essential. Zhao et al. recently introduced a user authentication scheme for the multi-server environment, utilizing passwords and smart cards, claiming resilience against well-known attacks. This paper conducts cryptanalysis on Zhao et al.'s scheme, focusing on denial of service and privacy attacks, revealing a lack of user-friendliness. Subsequently, we propose a new multi-server user authentication scheme for privacy preservation with fuzzy commitment over the IoT environment, addressing the shortcomings of Zhao et al.'s scheme. Formal security verification of the proposed scheme is conducted using the ProVerif simulation tool. Through both formal and informal security analyses, we demonstrate that the proposed scheme is resilient against various known attacks and those identified in Zhao et al.'s scheme.
Advanced Privacy Scheme to Improve Road Safety in Smart Transportation SystemsIJCNCJournal
In -Vehicle Ad-Hoc Network (VANET), vehicles continuously transmit and receive spatiotemporal data with neighboring vehicles, thereby establishing a comprehensive 360-degree traffic awareness system. Vehicular Network safety applications facilitate the transmission of messages between vehicles that are near each other, at regular intervals, enhancing drivers' contextual understanding of the driving environment and significantly improving traffic safety. Privacy schemes in VANETs are vital to safeguard vehicles’ identities and their associated owners or drivers. Privacy schemes prevent unauthorized parties from linking the vehicle's communications to a specific real-world identity by employing techniques such as pseudonyms, randomization, or cryptographic protocols. Nevertheless, these communications frequently contain important vehicle information that malevolent groups could use to Monitor the vehicle over a long period. The acquisition of this shared data has the potential to facilitate the reconstruction of vehicle trajectories, thereby posing a potential risk to the privacy of the driver. Addressing the critical challenge of developing effective and scalable privacy-preserving protocols for communication in vehicle networks is of the highest priority. These protocols aim to reduce the transmission of confidential data while ensuring the required level of communication. This paper aims to propose an Advanced Privacy Vehicle Scheme (APV) that periodically changes pseudonyms to protect vehicle identities and improve privacy. The APV scheme utilizes a concept called the silent period, which involves changing the pseudonym of a vehicle periodically based on the tracking of neighboring vehicles. The pseudonym is a temporary identifier that vehicles use to communicate with each other in a VANET. By changing the pseudonym regularly, the APV scheme makes it difficult for unauthorized entities to link a vehicle's communications to its real-world identity. The proposed APV is compared to the SLOW, RSP, CAPS, and CPN techniques. The data indicates that the efficiency of APV is a better improvement in privacy metrics. It is evident that the AVP offers enhanced safety for vehicles during transportation in the smart city.
DEF: Deep Ensemble Neural Network Classifier for Android Malware DetectionIJCNCJournal
Malware is one of the threats to security of computer networks and information systems. Since malware instances are available sufficiently, there is increased interest among researchers on usage of Artificial Intelligence (AI). Of late AI-enabled methods such as machine learning (ML) and deep learning paved way for solving many real-world problems. As it is a learning-based approach, accumulated training samples help in improving thequality of training and thus leveraging malware detection accuracy. Existing deep learning methods are focusing on learning-based malware detection systems. However, there is need for improving the state of the art through ensemble approach. Towards this end, in this paper we proposed a framework known as Deep Ensemble Framework (DEF) for automatic malware detection. The framework obtains features from training samples. From given malware instance a grayscale image is generated. There is another process to extract the opcode sequences. Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) techniques are used to obtain grayscale image and opcode sequence respectively. Afterwards, a stacking ensemble is employed in order to achieve efficient malware detection and classification. Malware samples collected fromthe Internet sources and Microsoft are used for theempirical study. An algorithm known as Ensemble Learning for Automatic Malware Detection (EL-AML) is proposed to realize our framework. Another algorithm named Pre-Process is proposed to assist the EL-AML algorithm for obtaining intermediate features required by CNN and LSTM.Empirical study reveals that our framework outperforms many existing methods in terms of speed-up and accuracy.
High Performance NMF based Intrusion Detection System for Big Data IoT TrafficIJCNCJournal
With the emergence of smart devices and the Internet of Things (IoT), millions of users connected to the network produce massive network traffic datasets. These vast datasets of network traffic, Big Data are challenging to store, deal with and analyse using a single computer. In this paper we developed parallel implementation using a High Performance Computer (HPC) for the Non-Negative Matrix Factorization technique as an engine for an Intrusion Detection System (HPC-NMF-IDS). The large IoT traffic datasets of order of millions samples are distributed evenly on all the computing cores for both storage and speedup purpose. The distribution of computing tasks involved in the Matrix Factorization takes into account the reduction of the communication cost between the computing cores. The experiments we conducted on the proposed HPC-IDS-NMF give better results than the traditional ML-based intrusion detection systems. We could train the HPC model with datasets of one million samples in only 31 seconds instead of the 40 minutes using one processor), that is a speed up of 87 times. Moreover, we have got an excellent detection accuracy rate of 98% for KDD dataset.
IoT Guardian: A Novel Feature Discovery and Cooperative Game Theory Empowered...IJCNCJournal
Cyber intrusion attacks increasingly target the Internet of Things (IoT) ecosystem, exploiting vulnerable devices and networks. Malicious activities must be identified early to minimize damage and mitigate threats. Using actual benign and attack traffic from the CICIoT2023 dataset, this WORK aims to evaluate and benchmark machine-learning techniques for IoT intrusion detection. There are four main phases to the system. First, the CICIoT2023 dataset is refined to remove irrelevant features and clean up missing and duplicate data. The second phase employs statistical models and artificial intelligence to discover novel features. The most significant features are then selected in the third phase based on cooperative game theory. Using the original CICIoT2023 dataset and a dataset containing only novel features, we train and evaluate a variety of machine learning classifiers. On the original dataset, Random Forest achieved the highest accuracy of 99%. Still, with novel features, Random Forest's performance dropped only slightly (96%) while other models achieved significantly lower accuracy. As a whole, the work contributes substantial contributions to tailored feature engineering, feature selection, and rigorous benchmarking of IoT intrusion detection techniques. IoT networks and devices face continuously evolving threats, making it necessary to develop robust intrusion detection systems.
Enhancing Traffic Routing Inside a Network through IoT Technology & Network C...IJCNCJournal
IoT networking uses real items as stationary or mobile nodes. Mobile nodes complicate networking. Internet of Things (IoT) networks have a lot of control overhead messages because devices are mobile. These signals are generated by the constant flow of control data as such device identity, geographical positioning, node mobility, device configuration, and others. Network clustering is a popular overhead communication management method. Many cluster-based routing methods have been developed to address system restrictions. Node clustering based on the Internet of Things (IoT) protocol, may be used to cluster all network nodes according to predefined criteria. Each cluster will have a Smart Designated Node. SDN cluster management is efficient. Many intelligent nodes remain in the network. The network design spreads these signals. This paper presents an intelligent and responsive routing approach for clustered nodes in IoT networks. An existing method builds a new sub-area clustered topology. The Nodes Clustering Based on the Internet of Things (NCIoT) method improves message transmission between any two nodes. This will facilitate the secure and reliable interchange of healthcare data between professionals and patients. NCIoT is a system that organizes nodes in the Internet of Things (IoT) by grouping them together based on their proximity. It also picks SDN routes for these nodes. This approach involves selecting one option from a range of choices and preparing for likely outcomes problem addressing limitations on activities is a primary focus during the review process. Predictive inquiry employs the process of analyzing data to forecast and anticipate future events. This document provides an explanation of compact units. The Predictive Inquiry Small Packets (PISP) improved its backup system and partnered with SDN to establish a routing information table for each intelligent node, resulting in higher routing performance. Both principal and secondary roads are available for use. The simulation findings indicate that NCIoT algorithms outperform CBR protocols. Enhancements lead to a substantial 78% boost in network performance. In addition, the end-to-end latency dropped by 12.5%. The PISP methodology produces 5.9% more inquiry packets compared to alternative approaches. The algorithms are constructed and evaluated against academic ones.
IoT Guardian: A Novel Feature Discovery and Cooperative Game Theory Empowered...IJCNCJournal
Cyber intrusion attacks increasingly target the Internet of Things (IoT) ecosystem, exploiting vulnerable devices and networks. Malicious activities must be identified early to minimize damage and mitigate threats. Using actual benign and attack traffic from the CICIoT2023 dataset, this WORK aims to evaluate and benchmark machine-learning techniques for IoT intrusion detection. There are four main phases to the system. First, the CICIoT2023 dataset is refined to remove irrelevant features and clean up missing and duplicate data. The second phase employs statistical models and artificial intelligence to discover novel features. The most significant features are then selected in the third phase based on cooperative game theory. Using the original CICIoT2023 dataset and a dataset containing only novel features, we train and evaluate a variety of machine learning classifiers. On the original dataset, Random Forest achieved the highest accuracy of 99%. Still, with novel features, Random Forest's performance dropped only slightly (96%) while other models achieved significantly lower accuracy. As a whole, the work contributes substantial contributions to tailored feature engineering, feature selection, and rigorous benchmarking of IoT intrusion detection techniques. IoT networks and devices face continuously evolving threats, making it necessary to develop robust intrusion detection systems.
** Connect, Collaborate, And Innovate: IJCNC - Where Networking Futures Take ...IJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
Enhancing Traffic Routing Inside a Network through IoT Technology & Network C...IJCNCJournal
IoT networking uses real items as stationary or mobile nodes. Mobile nodes complicate networking. Internet of Things (IoT) networks have a lot of control overhead messages because devices are mobile. These signals are generated by the constant flow of control data as such device identity, geographical positioning, node mobility, device configuration, and others. Network clustering is a popular overhead communication management method. Many cluster-based routing methods have been developed to address system restrictions. Node clustering based on the Internet of Things (IoT) protocol, may be used to cluster all network nodes according to predefined criteria. Each cluster will have a Smart Designated Node. SDN cluster management is efficient. Many intelligent nodes remain in the network. The network design spreads these signals. This paper presents an intelligent and responsive routing approach for clustered nodes in IoT networks. An existing method builds a new sub-area clustered topology. The Nodes Clustering Based on the Internet of Things (NCIoT) method improves message transmission between any two nodes. This will facilitate the secure and reliable interchange of healthcare data between professionals and patients. NCIoT is a system that organizes nodes in the Internet of Things (IoT) by grouping them together based on their proximity. It also picks SDN routes for these nodes. This approach involves selecting one option from a range of choices and preparing for likely outcomes problem addressing limitations on activities is a primary focus during the review process. Predictive inquiry employs the process of analyzing data to forecast and anticipate future events. This document provides an explanation of compact units. The Predictive Inquiry Small Packets (PISP) improved its backup system and partnered with SDN to establish a routing information table for each intelligent node, resulting in higher routing performance. Both principal and secondary roads are available for use. The simulation findings indicate that NCIoT algorithms outperform CBR protocols. Enhancements lead to a substantial 78% boost in network performance. In addition, the end-to-end latency dropped by 12.5%. The PISP methodology produces 5.9% more inquiry packets compared to alternative approaches. The algorithms are constructed and evaluated against academic ones.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
1. International Journal of Computer Networks & Communications (IJCNC) Vol.5, No.2, March 2013
SIMULATION OF COGNITIVE RADIO SYSTEM
APPLYING DIFFERENT WIRELESS CHANNEL
MODELS
Mohamed Shalaby1, Mona Shokair2, and Yaser S. E. Abdo3
1
National Institute for Standards, Tersa Street, Haram, Gizah, Egypt
Mhmd_shlpy@yahoo.com
2
Faculity of Electronic Engineering, Menoufia University, Menouf, Egypt
shokair_1999@hotmail.com
3
National Institute for Standards, Tersa Street, Haram, Gizah, Egypt
yaserabdo76@gmail.com
ABSTRACT
Cognitive radio is an emerging technology, which aims to upgrade the spectrum utilization by allowing the
secondary users to operate at the spectrum bands vacated by the primary users. A cognitive radio system
model was simulated and the performance of the energy detector was evaluated by using different wireless
channel models. These models include Additive White Gaussian Noise (AWGN) model, Rayleigh fading
model, and Rician fading model. The simulation results show that by increasing the signal to noise ratio,
the detection capability of the energy detector can be improved and the false alarm probability and the
missed detection probability can be reduced. Moreover, the line of sight path strength of the Rician fading
has a great effect on the energy detector performance. It was observed that, the line of sight path strength
(k) of 20 can save the signal power by 40 dB over a single path transmission and 25 dB over a multipath
transmission.
KEYWORDS
Cognitive Radio, Spectrum Sensing, Energy Detector & Wireless Channel Models
1. INTRODUCTION
Cognitive radio is a new technology designed specially to solve underutilization of the wireless
spectrum. Previous experiments, reported in [1, and 2] show that the spectrum utilization of any
fixed policy wireless network is within 6 % over the day. The spectrum is a valuable resource,
which may be wasted if it is underutilized. Cognitive radio can improve the utilization of any
wireless network by allowing secondary users to access the spectrum holes, or white spaces, left
by primary users who are licensed and have the rights to access the spectrum at anytime and
anywhere within the coverage area. The secondary users are guests; they can access the licensed
spectrum only, when the primary users are absent. Moreover, secondary users have to vacate the
channel, when the primary users start to access it. The presence and absence of the primary users
can be determined by applying spectrum sensing techniques. There are a lot of spectrum sensing
techniques, but the most popular methods are; matched filter detector, cyclostationary detector,
and energy detector which are explained in [1].
In this paper, a cognitive radio system, built using the energy detector, is proposed to distinguish
the primary users from the secondary users when the transmitted signal spectrum is presented.
DOI : 10.5121/ijcnc.2013.5214 181
2. International Journal of Computer Networks & Communications (IJCNC) Vol.5, No.2, March 2013
The ability of the energy detector to determine the empty slots within the spectrum, in order to be
utilized by secondary users is verified. Moreover the energy detector performance is estimated
using different wireless channel models.
The cognitive radio system is defined in Section 2. Subsequently, in Section 3, the spectrum
sensing process of the cognitive radio system is stated. Different models used to represent the
wireless channel behavior are explained in Section 4. Finally, in Section 5, the simulation results
are discussed.
2. COGNITIVE RADIO
There are different definitions of the cognitive radio. One of them defines the cognitive radio as
the radio system which can change its transceiver parameters based on the interaction with the
surrounding radio environment and have complete awareness about the surrounding
electromagnetic spectrum [1, and 2]. There is another definition that describes the cognitive radio
as a soft ware defined radio that additionally senses its radio environment, tracks changes, and
reacts up on its findings [3]. To have a cognitive system, it must have two capabilities; the
cognitive capability and the reconfigureability. The cognitive capability refers to the ability of
cognitive system to be fully aware about the surrounding electromagnetic spectrum through the
cognitive cycle [2, and 4]. Reconfigureability is the process by which the cognitive radio system
can adapt its transceiver parameters according to the new operating parameters. Since the
cognitive radio becomes an important technique, it was supported by the standards of IEEE
802.22 and SCC41 [5, and 6]. A cognitive radio architecture was handled in [7], while the basic
building blocks and a lot of elements which are necessary in this system were stated in [8].
The system model proposes five primary users; each user message is modulated by using an
amplitude modulation (AM) technique, as shown in Figure 1 which presents the proposed system.
The transmitted signal is the summation of five primary users' signals. Power spectral density
(PSD) is estimated for the transmitted signal by applying periodogram method, which can help to
display the cognition process among primary users and the secondary one. The secondary user
will occupy the first vacant slot, and ask for emptying a slot, if all slots are occupied. The noise
effect on the transmitted signal is studied by displaying the received signal spectrum after
applying different signal to noise ratio values. The cognitive radio model was suggested before in
[9], but the proposed model here extends the study to cover the attenuation effect and the fading
channels.
To explain the cognition process among the primary users and the secondary one, the primary
users are chosen to have the frequencies of 1, 2, 3, 4, and 5 MHz, respectively. Figure 2(a)
illustrates the PSD of the transmitted signal assuming 1st, 3rd, and 5th primary users are present.
Note that there are power peaks at their frequency bands and no power peaks at the 2nd, and 4th
bands. Plotting the power spectral density allows the cognition of the user power value at a
certain frequency band, so it is a good indicator for the user activity. Moreover, integrating the
user power spectral density results in the user energy and this can be used to verify the energy
detector performance. Figure 2(b) displays the PSD of the transmitted signal, when the secondary
user accesses the 2nd slot. In this case, there are power peaks at this slot due to the secondary user
activity. Figure 2(c) illustrates the transmitted signal spectrum, when the secondary user accesses
the 4th slot, and hence the power peaks exist at this slot. Figure 2(d) shows the PSD of the
transmitted signal, when the 5th primary user leaves, so that there are no power peaks at the 5th
slot. The secondary user accesses the 5th slot after the primary user departure, so the power peaks
appear at this slot, as shown in Figure 2(e).
182
3. International Journal of Computer Networks & Communications (IJCNC) Vol.5, No.2, March 2013
Figure 1. The proposed cognitive radio model.
Power Spectral Density P o we r S p e c tral D e ns ity
5
P o w e r / fre q u e n c y (d B / H z )
Power / frequency (dB / Hz)
0
0
-5
-10
-1 0
-20 -1 5
-2 0
-30
-2 5
-40 -3 0
0 1 2 3 4 5 6 0 1 2 3 4 5 6
Frequency (MHz) F re q ue nc y (M Hz)
(a) (b)
Power Spectral Density Power Spectral Density
5
0
0
Power / frequency (dB / Hz)
Power / frequency (dB / Hz)
-5 -10
-10
-20
-15
-30
-20
-25 -40
-30 0 1 2 3 4 5 6
0 1 2 3 4 5 6
Frequency (MHz) Frequency (MHz)
(c) (d)
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Power Spectral Density
5
0
Power / frequency (dB / Hz)
-5
-10
-15
-20
-25
-30
-35
-40
0 1 2 3 4 5 6
Frequency (MHz)
(e)
Figure 2. The cognition and the spectrum sharing process among five primary users and the secondary
user.
3. SPECTRUM SENSING IN COGNITIVE RADIO
Spectrum sensing is the process that the cognitive user can determine the spectrum holes or white
spaces left by primary users [1, and 2]. Spectrum holes are the frequency bands, or the time slots
provided for a primary user operation, but they may be vacant at certain location and time. The
success of secondary users to utilize these bands depends on their detection capability. Spectrum
sensing can be considered as the most important stage in any cognitive radio system. If it is not
carried out properly, the cognitive radio system will not be successful. There are a lot of spectrum
sensing methods; such as matched filter detector, cyclostationary feature detector, and energy
detector.
The ability of matched filter to increase the signal to noise ratio at the sampling instant is the key
for being used as a sensor [10, 11, and 12]. Unfortunately, it cannot be used without the existence
of priori information about the primary user signal. Pilot signals are used to overcome this
problem.
The cyclostationary detector depends on estimating the spectral correlation of the received signal
and then decides the presence or absence of a primary user [10, 11, and 12].The signal is
cyclostationary, if its mean and autocorrelation function are periodic. The modulated signals are
cyclostationary with a spectral correlation, but the noise is a random signal with no correlation.
Energy detector is the best spectrum sensing method when no priori information about the
primary user signal is available. The energy detector block diagram is presented in Figure 3 [9].
In the beginning, a secondary user scans a certain spectrum band which is licensed for a primary
user, and then the received signal is converted to the digital domain by means of an A/D
converter. Fast Fourier Transform (FFT) is an important stage, which is used to obtain the
spectral components of the received digital signal. The signal energy can be obtained if the
summation of the squared spectral components of the signal is averaged over certain time
interval. The calculated energy is compared to a threshold value to decide if the primary user is
present or absent. The primary user is present, if the received energy is more than the threshold
value.
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Threshold value is an important factor to determine the performance of the detector. It has a great
effect on the probability of detection and the probability of false alarm. However the energy
detector design is simple, it has several limitations; such as it has a high false alarm probability
due to the noise uncertainty, more samples are required to achieve acceptable performance, and it
has a low performance when shot noise and fading channels are applied [10, 11, and 12].
The performance of the energy detector can be evaluated by three parameters and they are; the
probability of detection, the probability of missed detection, and the probability of false alarm.
The probability of detection is the number of the detected primary users (identified by the energy
detector) divided by the total number of the primary users who are assumed to be present in the
beginning. The probability of missed detection is the number of primary users that cannot be
detected, divided by the total number of primary users who are assumed to be present in the
beginning. The probability of false alarm is the number of the detected primary users divided by
the total number of primary users who are assumed to be absent in the beginning. The
performance of the energy detector is evaluated by sending first, third, and fifth primary users
when the second and the forth primary users are absent. Then, its ability to identify the present
primary users from the absent ones is checked.
Figure 3. The block diagram of the digital energy detector.
4. WIRELESS CHANNEL MODELS
The difference between a wire and a wireless communication is the channel. A wireless channel
behavior varies with the time. However all the models, used to describe the behavior of a wireless
link, are not exactly accurate, they can provide an acceptable approximation. There are a lot of
models that can describe the wireless channel behavior; such as an Additive White Gaussian
Noise model and the fading models. Rayleigh and Rician models are the most famous models of
fading.
4.1. Additive White Gaussian Noise
The simplest radio environment, in which a wireless communications system operates, is the
Additive White Gaussian Noise (AWGN) environment [13]. A random signal is added to the
transmitted signal due to the channel effect. So that, the received signal, s(t), can be expressed as;
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s (t ) = x(t ) + n(t ) (1)
where x(t) is the transmitted signal, and n(t) is the background noise.
4.2. Fading Channels
A fading channel is the communication channel that has to face different fading phenomenon
during the signal transmission [13, 14, 15, 16, and 17]. The main cause of fading is the multipath
propagation. The signal arrives to the receiver from different paths, which have different delays
and different path gains. These paths of propagation may be constructive or destructive. The
received signal is the algebraic summation of the different paths of propagation, so some of the
paths are added and the other are subtracted.
4.2.1. Rayleigh Fading Model
The Rayleigh fading is primarily caused by multipath reception of the transmitted signal. It can
model the wireless channel, when there is no direct line of sight between the transmitter and the
receiver. This fading model considers the signal arrived to the receiver as the algebraic
summation of the received signals from different paths, in absence of the direct line of sight
between the transmitter and receiver. Consider the transmitted signal, x(t), is;
x(t ) = cos(ct ) (2)
where c is the transmitted signal frequency in rad/sec, so the received signal, s(t), can be
written as;
N
s (t ) = ∑ ai cos(ct + i ) (3)
i =1
Where N is the number of paths, i is the phase shift of each path, which depends on the delay
difference and takes values from 0 to 2 , and ai is the amplitude of each path i. When there is a
c v
relative motion between the transmitter and the receiver, the term di = cos i should be
c
added to represent the Doppler Effect, and hence the received signal can be expressed as;
N
s (t ) = ∑ ai cos(ct + di t + i ) (4)
i =1
where di is the Doppler frequency of path i, v is the velocity of a mobile unit, c is the velocity of
the light, and i is the received signal direction relative to the motion direction of the antenna.
The received signal can be separated into inphase and quadrature components as follow;
s (t ) = I (t ) cos ct − Q (t ) sin ct (5)
The inphase and quadrature components can be expressed as;
N
I (t ) = ∑ ai cos(di t + i ) (6)
i =1
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N
Q (t ) = ∑ ai sin(di t + i ) (7)
i =1
and the envelope of s(t), r, can be calculated as;
r = [ I (t )]2 + [Q (t )]2 (8)
If N is large enough, the inphase and quadrature components can have a Gaussian distribution.
The probability density function (pdf) of the received signal envelope can be expressed as;
r r2
f (r ) = exp( − ) r≥0 (9)
2
2 2
where σ2 is the variance.
4.2.2. Rician Fading Model (Nakagami-n model)
This model is similar to the Rayleigh fading model except, the existence of a strong dominant
component. This dominant component is a stationary (non fading) component and it is commonly
known as the LOS (Line of Sight) component. The received signal can be expressed as;
N −1
s (t ) = ∑ ai cos(c t + di t + i ) + k d cos(c t + d t ) (10)
i =1
where Kd is the line of sight path strength, ωdi is the Doppler spread of each indirect component,
and ωd is the Doppler spread of the strong line of sight component. The envelope of the Rician
fading,r, has a probability density function f(r);
r r 2 + kd2
rkd
f (r ) = exp(− )Io ( 2 ) r≥0 (11)
2
2 2
where I o () is the 0th order modified Bessel function of the first kind.
2
kd
The Rician fading is usually described by a K factor K ( dB ) = 10 log10 ( ) , which is an
2 2
indication of the component strength of the direct line of sight. The Rician fading can be reduced
2
kd r2
to a corresponding Rayleigh one, if k d = 0 or as the direct path is eliminated,
2 2 2 2
K (dB ) = −∞ .
5. SIMULATION RESULTS
In this section, the proposed system, shown in Figure 1, is simulated, and the effect of adding
noise to the transmitted signal is investigated. The 1st, 3rd, and 5th primary users are assumed to be
present and the secondary user accesses the second slot. Figure 4(a) shows the received signal
spectrum when S/N= 14 dB. It is obvious that when the signal to noise ratio has a large value, the
received signals still can be differentiated and recognized. Figure 4(b) presents the case when
signal to noise ratio S/N= 6 dB. It is clear that, as the signal to noise ratio becomes lower, the
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signals can also be identified, but it is more distorted than the previous case. Figures 4(c) and 4(d)
display the PSD of the received signal when S/N= -6 dB, and S/N= -14 dB respectively. In this
case, the signal to noise ratio has a low values. Therefore the signals become more distorted and
cannot be identified.
Power Spectral Density Power Spectral Density
10
0
5
Power / frequency (dB / Hz)
Power / frequency (dB / Hz)
0
-10
-5
-20 -10
-15
-30
-20
-40 -25
-30
0 1 2 3 4 5 6 0 1 2 3 4 5 6
Frequency (MHz) Frequency (MHz)
(a) (b)
Power Spectral Density Power Spectral Density
10 20
5 15
Power / frequency (dB / Hz)
Power / frequency (dB / Hz)
0 10
-5 5
-10 0
-15 -5
-20 -10
-25 -15
-30 -20
0 1 2 3 4 5 6 0 1 2 3 4 5 6
Frequency (MHz) Frequency (MHz)
(c) (d)
Figure 4. The noise effect on the transmitted signal spectrum at S/N of a) 14 dB, b) 6 dB, c) -6 dB, and d) -
14 dB.
Table 1 shows the noise effect on the performance of the energy detector. From Table 1, it is
obvious that the signals, arrive with high signal to noise ratio values, can be detected easily. On
the other hand, the performance of the energy detector becomes not slightly satisfied, when the
signal to noise ratio value decreases. There is a tradeoff between the signal to noise ratio and the
false alarm probability to achieve a certain performance. By allowing the energy detector to
detect the weak signals, it becomes more prone to the false alarms.
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Table 1. The performance of the energy detector in its digital form applying AWGN.
Signal / Noise Pd Pfa Pmd
14
(dB) 1 0 0
12 1 0 0
10 1 0 0
8 1 0 0
6 1 0 0
4 1 0 0
2 1 0 0
-2 1 0 0
-4 1 0.5 0
-6 1 0.5 0
-8 1 0.5 0
-10 1 1 0
-12 1 1 0
-14 0.66 1 0.33
The attenuation effect on the transmitted signal waveform is studied, and the performance of the
energy detector is evaluated using different attenuation values. From Figure 5(a, b, and c), which
plots the attenuated amplitude of the received signal versus the time, it is obvious that more
attenuation leads to more loss of the signal amplitude. Moreover, increasing the attenuation
percentage results in decreasing the probability of detection and increasing the missed detection
probability, as shown in Table 2 that states the performance of the energy detector in this case.
The energy detector performance becomes worse when the received signals have a high
attenuation percentage.
Table 2. The energy detector performance applying different attenuation percentage.
Attenuation Pd Pfa Pmd
10 % 1 0 0
20 % 1 0 0
30 % 1 0 0
40 % 1 0 0
50 % 0 0 1
60 % 0 0 1
70 % 0 0 1
80 % 0 0 1
90 % 0 0 1
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Received Signal at 10% Attenuation Received Signal at 50% Attenuation
4 2
3 1.5
Received Signal Amplitude
Received Signal Amplitude
2 1
1 0.5
0 0
-1 -0.5
-2 -1
-3 -1.5
-4 -2
0 200 400 600 800 1000 0 200 400 600 800 1000
Time [µsec] Time [µsec]
(a) (b)
Received Signal at 90% Attenuation
0.4
0.3
Received Signal Amplitude
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
0 200 400 600 800 1000
Time [µsec]
(c)
Figure 5. The received signal waveform at attenuation values of a) 10%, b) 50%, and c) 90%.
The effect of a single path Rayleigh fading (supposing that the mobile user has a velocity (v) of
216 Km/h) on the transmitted signal is studied. From the simulation results, it was found that the
minimum S/N value, which can make the probability of detection of the energy detector have a
value of one with no false alarms, is equal to 40 dB. The reason for this low performance is the
fading, which causes a great reduction of the signal strength, and consequently the performance
of the energy detector is degraded. The fading causes an inter modulation distortion, therefore
new frequency components appear in the received signal as shown in Figure 6, which displays the
received signal spectrum at S/N value of 40 dB. The signal power of each user escapes to these
new frequency components, and hence the power loss is increased.
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Power Spectral Density
5
0
Power / frequency (dB / Hz)
-5
-10
-15
-20
-25
-30
0 1 2 3 4 5 6
Frequency (MHz)
Figure 6. The received signal spectrum applying a single path Rayleigh fading channel at S/N value of 40
dB.
The effect of a single path Rician fading (v=216 Km/h and k=0.1) on the transmitted signal is
studied. The minimum S/N value, which can make the probability of detection of the energy
detector have a value of one with no false alarms, was computed and it is equal to 40 dB. Figure 7
displays the received signal spectrum at S/N value of 40 dB. The performance in this case is
similar to the corresponding one which applies a single path Rayleigh fading, since the value of k
factor is very small.
Power Spectral Density
5
0
Power / frequency (dB / Hz)
-5
-10
-15
-20
-25
-30
0 1 2 3 4 5 6
Frequency (MHz)
Figure 7. The received signal spectrum applying a single path Rician fading (k=0.1) at S/N value of 40 dB.
The effect of a single path Rician fading (v=216 Km/h and k=20) on the transmitted signal is
studied. By increasing the value of k to be 20, the minimum value of S/N, which can make the
probability of detection of the energy detector have a value of one with no false alarms, is
decreased to 0 dB. Figure 8 displays the received signal spectrum at S/N value of 0 dB. The
performance in this case is very good and similar to the corresponding one without fading. This is
due to the effective line of sight component.
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Power Spectral Density
5
Power / frequency (dB / Hz)
0
-5
-10
-15
-20
-25
0 1 2 3 4 5 6
Frequency (MHz)
Figure 8. The received signal spectrum applying a single path Rician channel (k=20) at S/N value of 0 dB.
From the simulation results of different Rician fading models, it is obvious that; the value of k
factor has a great effect on the performance of the energy detector. When it is very small, a Rician
fading and a Rayleigh fading have the same effect on the performance of the energy detector. On
the other hand, when k factor has higher values, the performance of the energy detector becomes
better. This result agrees with the theoretical analysis of the difference between Rayleigh and
Rician fading.
The effect of a multipath Rayleigh fading (v=216 Km/h) on the transmitted signal is studied. It is
noticed that; the minimum S/N value, which can make the probability of detection of the energy
detector have a value of one with no false alarms, is equal to 60 dB. Figure 9 displays the
received signal spectrum at S/N value of 60 dB. The performance in this case is very poor.
Power Spectral Density
0
Power / frequency(dB / Hz)
-10
-20
-30
-40
0 1 2 3 4 5 6
Frequency (MHz)
Figure 9. The received signal spectrum applying a multipath Rayleigh fading channel at S/N value of 60
dB.
The effect of a multipath Rician fading (v=216 Km/h and k=20) on the transmitted signal is
studied. By increasing the value of k to be 20, the minimum value of S/N, which can make the
probability of detection of the energy detector have a value of one with no false alarms, is
decreased to 35 dB. Figure 10 displays the received signal spectrum at S/N value of 35 dB. The
performance in this case is better than a Rayleigh multipath case due to the existence of the
efficient direct line of sight component.
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Power Spectral Density
10
Power / frequency (dB / Hz)
0
-10
-20
-30
-40
0 1 2 3 4 5 6
Frequency (MHz)
Figure 10. The received signal spectrum applying a multipath Rician fading channel at S/N value of 35 dB.
6. CONCLUSIONS
The cognitive radio simulation model was proposed, and the ability of the secondary users to
identify the spectrum bands vacated by primary users was illustrated. The transmitted signal
power spectral density was plotted and it is obvious that there are power peaks at the primary user
who is presented, and no power peaks at the user who is absent. When the secondary user
accesses certain spectrum slot, the power peaks can be observed at this slot. The energy detector
performance in its digital form was evaluated applying an Additive White Gaussian Noise
(AWGN) channel and the fading channels. From the simulation results, it is obvious that the
performance of the energy detector is better, when an AWGN channel is applied than the fading
channels. The simulation results of the proposed energy detector, when Rician fading model is
applied, show the great effect of the line of sight strength on the detector performance. The
energy detector performance is the same, applying Rayleigh channel and Rician channel, when k
factor is small. This result agrees with the theoretical analysis of the difference between Rayleigh
and Rician fading. The energy detector performance becomes better, when k factor is increased. It
was observed that; the line of sight path strength (k) value of 20 can save the signal power by 40
dB over a single path transmission and 25 dB over a multipath transmission.
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Authors
Mohamed Shalaby was born in Menoufia, Egypt, in 1986. He received the B.Sc. degree in
electronics, and electrical communication engineering from Menoufia University, Menoufia,
Egypt, in 2008. Presently, he is an Assistant Researcher at the National Institute for Standards,
Cairo, Egypt. His research interests include wireless communications, broadband technologies,
mobile communications, and next generation networks.
Mona Shokair received the B.Sc., and M.Sc. degrees in electronics engineering from Menoufia
University, Menoufia, Egypt, in 1993, and 1997, respectively. She received the Ph.D. degree
from Kyushu University, Japan, in 2005. She received VTS chapter IEEE award from Japan, in
2003. She published about 40 papers until 2011. She received the Associated Professor degree in
2011. Presently, she is an Associated Professor at Menoufia University. Her research interests
include adaptive array antennas, CDMA system, WIMAX system, OFDM system, and next
generation networks.
Yaser S. E. Abdo was born in Mansoura, Egypt, in 1976. He received the B.Sc., and M.Sc.
degrees from Mansoura University, Mansoura, Egypt, in 1998, and 2004, respectively, and the
Ph.D. degree in electrical engineering from Royal Military College, Kingston, Canada, in 2012.
From 1999 to 2005, he worked as an Assistant Researcher at the National Institute for Standards,
Cairo, Egypt. From 2006 to 2012, he was a Research Assistant at the Royal Military College,
Kingston, Canada. Presently, he is a Researcher at the National Institute for Standards, Cairo,
Egypt. His research interests include microwave measurements, EBG structures, leaky-wave antennas, near-field
measurements, wireless communications, and electromagnetic compatibility.
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