This paper considers power domain based multiple access (PDMA) in cognitive radio network to serve numerous users who intend to multiple access to core network. In particular, we investigate the effect of signal combination scheme equipped at PDMA end-users as existence of direct link and relay link. This system model using relay scheme provides performance improvement on the outage probability of two PDMA end-users. We first propose a simple scheme of fixed power allocation to PDMA users who exhibit performance gap and fairness. Inspired by PDMA strategy, we then find signal to noise ratio (SNR) to detect separated signal for each user. In addition, the exact expressions of outage probability are derived in assumption that receiver can cancel out the interference completely with successive interference cancellation (SIC). By exploiting theoretical and simulation results, both considered combination schemes (Maximal Ratio Combining (MRC) and Selection Combining (SC) can achieve improved performance of two PDMA users significantly.
Performance Comparison of Multi-Carrier CDMA Using QPSK and BPSK ModulationIOSR Journals
Abstract: MC-CDMA (Multi Carrier Code Division Multiple Access) plays an important role in modern wireless communications. Modern communication required an efficient spectrum usage and capacity and throughput.MC-CDMA provided the solution of these problems. MIMO refers to links with multiple antennas at the transmitter and receiver side. CDMA systems combined with multiple antennas is a promising technique, beyond 3G and 4G wireless communications. MIMO provides spatial diversity, which mitigates the fading. The usage of multiple antennas can significantly improve the performance of wireless communication system. This work also derives simulation through MATLAB of average bit error rate verses bit energy to noise ratio of multicarrier code division multiple access over Rayleigh channel using QPSK and BPSK modulation additive white Gaussian noise. Keywords: AWGN,BER,MC-CDMA, QPSK Modulation, Rayleigh Channel.
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.
Study on transmission over Nakagami-m fading channel for multiple access sche...TELKOMNIKA JOURNAL
In this paper, a downlink performance in non-orthogonal multiple access (NOMA) system is considered. With regard to different priority for two NOMA users, we exploit the closed-form expressions of outage probability over wireless fading channel following Nakagami-m fading. The fixed power allocation factor scheme is examined to reduce the complexity in computation regarding performance analysis. In our analysis, perfect successive interference cancellation (SIC) is applied in order to achieve perfect signal decoding operation. Simulation results show that the considered NOMA downlink scheme is affected by transmit SNR, power allocation factors, fading parameters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Equalization & Channel Estimation of Block & Comb Type CodesAM Publications
Multi-carrier code division multiple access is an attractive choice for high speed wireless communication as it mitigates
the problem of inter symbol interference and also exploits frequency diversity. The work described in this paper is my effort in this
direction. In this paper working of Transmitter and Receiver model of MCCDMA system is presented. We evaluated interference
and bit error rate for multicarrier code division multiple access wireless communication system. In this thesis my concern is find
out the effect of interference in MC-CDMA system. We find out the effect of number of users and signal power on different
parameters for MC-CDMA system. Simulations are given to support the system and receiver design. All the simulation is carried out on MATLAB tool.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
Performance Comparison of Multi-Carrier CDMA Using QPSK and BPSK ModulationIOSR Journals
Abstract: MC-CDMA (Multi Carrier Code Division Multiple Access) plays an important role in modern wireless communications. Modern communication required an efficient spectrum usage and capacity and throughput.MC-CDMA provided the solution of these problems. MIMO refers to links with multiple antennas at the transmitter and receiver side. CDMA systems combined with multiple antennas is a promising technique, beyond 3G and 4G wireless communications. MIMO provides spatial diversity, which mitigates the fading. The usage of multiple antennas can significantly improve the performance of wireless communication system. This work also derives simulation through MATLAB of average bit error rate verses bit energy to noise ratio of multicarrier code division multiple access over Rayleigh channel using QPSK and BPSK modulation additive white Gaussian noise. Keywords: AWGN,BER,MC-CDMA, QPSK Modulation, Rayleigh Channel.
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.
Study on transmission over Nakagami-m fading channel for multiple access sche...TELKOMNIKA JOURNAL
In this paper, a downlink performance in non-orthogonal multiple access (NOMA) system is considered. With regard to different priority for two NOMA users, we exploit the closed-form expressions of outage probability over wireless fading channel following Nakagami-m fading. The fixed power allocation factor scheme is examined to reduce the complexity in computation regarding performance analysis. In our analysis, perfect successive interference cancellation (SIC) is applied in order to achieve perfect signal decoding operation. Simulation results show that the considered NOMA downlink scheme is affected by transmit SNR, power allocation factors, fading parameters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Equalization & Channel Estimation of Block & Comb Type CodesAM Publications
Multi-carrier code division multiple access is an attractive choice for high speed wireless communication as it mitigates
the problem of inter symbol interference and also exploits frequency diversity. The work described in this paper is my effort in this
direction. In this paper working of Transmitter and Receiver model of MCCDMA system is presented. We evaluated interference
and bit error rate for multicarrier code division multiple access wireless communication system. In this thesis my concern is find
out the effect of interference in MC-CDMA system. We find out the effect of number of users and signal power on different
parameters for MC-CDMA system. Simulations are given to support the system and receiver design. All the simulation is carried out on MATLAB tool.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
PERFORMANCE EVALUATION OF MC-CDMA SYSTEM OVER RAYLEIGH FADING CHANNELIJCSES Journal
Multi Carrier Code Division Multiple Access (MC-CDMA) is a well known technique for high speed
wireless data transmission .Two advanced technology was included in the MC-CDMA structure, such as
orthogonal frequency division multiplex (OFDM) and the code division multiple access (CDMA),so that it
benefits from the robustness of OFDM against multipath environment and from the capability of multiuser
multiplexing services that is achieved via (CDMA) system. MC-CDMA is a multicarrier spread spectrum
system which is classified as the candidate scheme for future mobile radio systems. In this paper MCCDMA
system, with Rayleigh fading channel and 16QAM array modulation, was simulated to investigate
the effects of different parameters on the system performance, such as processing gain; number of paths;
number of users; interleaving; and coding ratio.MC-CDMA performances can be considerably improved
by proper selection of these parameters. As expected, results show that MC-CDMA has a better performance over CDMA system.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
A bi scheduler algorithm for frame aggregation in ieee 802.11 nijwmn
IEEE 802.11n mainly aims to provide high throughput, reliability and good security over its other previous
standards. The performance of 802.11n is very effective on the saturated traffic through the use of frame
aggregation. But this frame aggregation will not effectively function in all scenarios. The main objective of
this paper is to improve the throughput of the wireless LAN through effective frame aggregation using
scheduler mechanism. The Bi-Scheduler algorithm proposed in this article aims to segregate frames based
on their access categories. The outer scheduler separates delay sensitive applications from the incoming
burst of multi-part data and also decides whether to apply Aggregated - MAC Service Data Unit (AMSDU)
aggregation technique or to send the data without any aggregation. The inner scheduler schedules
the remaining (delay-insensitive, background and best-effort) packets using Aggregated-MAC Protocol
Data unit (A-MPDU) aggregation technique.
Performance of the MIMO-MC-CDMA System with MMSE EqualizationTamilarasan N
Multipath fading and spectral crowding are the
major challenges in dealing higher data rate in future
broadband wireless communication system. Multi-carrier
Modulation like Multicarrier code division multiple access
(MC-CDMA) can tackle the problem and provide higher data
rate for future wireless communication system. However,
through a frequency selective fading channel, the subcarriers
in MC-CDMA signal have different amplitude levels and phase
shifts which result in loss of the orthogonality among users
and generates Multiple access interference (MAI). To combat
the MAI, various amplitude and phase equalizing techniques
such as Maximum Ratio Combining (MRC), Equal Gain
Combining (EGC), Orthogonal Restoring Combining (ORC),
Threshold Orthogonal Restoring Combining or Minimum
Mean Square Error (MMSE) may be used. Out of these MMSE
offers better performance since the MMSE criterion is applied
independently on each subcarrier. Further improvement in
performance is possible through space–time block coding,
which offers maximum diversity gain and multiplexing gain.
This paper combines MC-CDMA with MMSE equalization
and space–time block coding which proves to be a powerful
physical layer solution in combating delay spread and inter
symbol interference (ISI).
Estimation and design of mc ds-cdma for hybrid concatenated coding in high sp...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This paper presents the design and performance comparison of a two stage
operational amplifier topology using CMOS and BiCMOS technology. This conventional op
amp circuit was designed by using RF model of BSIM3V3 in 0.6 μm CMOS technology and
0.35 μm BiCMOS technology. Both the op amp circuits were designed and simulated,
analyzed and performance parameters are compared. The performance parameters such as
gain, phase margin, CMRR, PSRR, power consumption etc achieved are compared. Finally,
we conclude the suitability of CMOS technology over BiCMOS technology for low power
RF design.
ABSTRACT : Performance enhancement of smart antennas versus their complexity for commercial wireless
applications. The goal of the study presented in this paper is to investigate the performance improvement
attainable using relatively simple smart antenna techniques when applied to the third-generation W-CDMA air
interface. Methods to achieve this goal include fixed multi beam architectures with different beam selection
algorithms (maximum power criterion, combined beams) or adaptive solutions driven by relatively simple direction
finding algorithms. After comparing these methods against each other for several representative scenarios, some
issues related to the sensitivity of these methods are also studied, (e.g., robustness to environment, mismatches
originating from implementation limitations, etc.). Results indicate that overall, conventional beam forming
seems to be the best choice in terms of balancing the performance and complexity requirements, in particular
when the problem with interfering high-bit-rate W-CDMA 3g users is considered.
Using the Channel State Information (CSI) at the transmitter is fundamental for the precoder
design in Multi-user Multiple Input Single Output (MU-MISO-OFDM) systems. In Frequency
Division Duplex (FDD) systems, CSI can be just available at the transmitter through a limited
feedback channel [1], where we assume that each user quantizes its channel direction with a
finite number of quantization bits. In this paper, we consider a scalar quantization (SQ) scheme
of the Channel Direction Information (CDI). Although vector quantization (VQ) schemes [2],
[3] still outperform this scalar scheme in terms of quantization error and Sum rate, the former
scheme suffers from an exponential search complexity and high storage requirements at the
receiver for high number of feedback bits.
Comparative Performance Assessment of V-Blast Encoded 8×8 MIMO MC-CDMA Wirele...pijans
The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system
for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM)
schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system
employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN
channel and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study
demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2-
rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance
utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission
Some of the key driving forces behind the transition from the UMTS based cellular system to the Long Term Evolution Advanced (LTE-A) are to improve the mean and the cell-edge throughput, improve the user fairness, and improve the quality of service (QoS) satisfaction for all users. In the latter system, relays appear as one of the most prominent enabler for improving the cell-edge user experience while increasing the system’s fairness.
In this white paper, we present the basics of relay deployments in LTE-A networks. Moreover, we analyze resource allocation problem for Relay Nodes (RN) deployments and present some of the solutions for improvement in system resource usage and QoS satisfaction. Afterwards, we introduce the capabilities of NOMOR’s LTE-A system level simulator and evaluate the performance of LTE-A relay systems under the described solutions.
PERFORMANCE OF MIMO MC-CDMA SYSTEM WITH CHANNEL ESTIMATION AND MMSE EQUALIZATIONTamilarasan N
The quality of a wireless link can be described by three basic parameters, namely transmission rate, transmission range
and transmission reliability. With the advent of multiple-input multiple-output (MIMO) assisted Multicarrier code
division multiple access (MC-CDMA) systems, the above-mentioned three parameters may be simultaneously
improved. The MC-CDMA combined with the MIMO technique, has become a core technology for future mobile radio
communication system. However, possible potential gain in spectral efficiency is challenged by the receiver’s ability to
accurately detect the symbol due to inter symbol interference (ISI). Multipath propagation, mobility of transmitter,
receiver and local scattering cause the signal to be spread in frequency, different arrival time and angle, which results in
ISI in the received signal. This will affect overall system performance. The use of MC-CDMA mitigates the problem of
time dispersion. However, still it is necessary to remove the amplitude and phase shift caused by channel. To solve this
problem, a multiple antenna array can be used at the receiver, not only for spectral efficiency or gain enhancement, but
also for interference suppression. This can be done by the, efficient channel estimation with strong equalization. This
paper proposes MIMO MC-CDMA system, Minimum mean square error (MMSE) equalization with pilot based
channel estimation. The simulation result shows improved Bit error rate (BER) performance when the sub carrier (SC)
and antenna configuration were increased
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
Iterative network channel decoding with cooperative space-time transmissionijasuc
One of the most efficient methods of exploiting space diversity for portable wireless devices is cooperative
communication utilizing space-time block codes. In cooperative communication, users besides
communicating their own information, also relay the information of other users. In this paper we
investigate a scheme where cooperation is achieved using two methods, namely, distributed space-time
coding and network coding. Two cooperating users utilize Alamouti space time code for inter-user
cooperation and in addition utilize a third relay which performs network coding. The third relay does not
have any of its information to be sent. In this paper we propose a scheme utilizing convolutional code based
network coding, instead of conventional XOR based network code and utilize iterative joint networkchannel
decoder for efficient decoding. Extrinsic information transfer (EXIT) chart analysis is performed to
investigate the convergence property of the proposed decoder.
Enabling relay selection in non-orthogonal multiple access networks: direct a...TELKOMNIKA JOURNAL
In this paper, we consider downlink non-orthogonal multiple access (NOMA) in which the relay selection (RS) scheme is enabled for cooperative networks. In particular, we investigate impact of the number of relays on system performance in term of outage probability. The main factors affecting on cooperative NOMA performance are fixed power allocations coefficients and the number of relay. This paper also indicate performance gap of the outage probabilities among two users the context of NOMA. To exhibit the exactness of derived formula, we match related results between simulation and analytical methods. Numerical results confirms that cooperative NOMA networks benefit from increasing the number of relay.
Performance of cluster-based cognitive multihop networks under joint impact o...TELKOMNIKA JOURNAL
In this paper, we evaluate outage probability (OP) of a cluster-based multi-hop protocol operating
on an underlay cognitive radio (CR) mode. The primary network consists of multiple independent
transmit/receive pairs, and the primary transmitters seriously cause co-channel interference (CCI) to the
secondary receivers. To improve the outage performance for the secondary network under the joint impact
of the CCI and hardware imperfection, we employ the best relay selection at each hop. Moreover, the
destination is equipped with multiple antennas and uses the selection combining (SC) technique to
enhance the reliability of the data transmission at the last hop. For performance evaluation, we first derive
an exact formula of OP for the primary network which is used to calculate the transmit power of the
secondary transmitters. Next, an exact closed-form expression of the end-to-end OP for the secondary
network is derived over Rayleigh fading channels. We then perform Monte-Carlo simulations to validate
the derivations. The results present that the CCI caused by the primary operations significantly impacts on
the outage performance of the secondary network.
PERFORMANCE EVALUATION OF MC-CDMA SYSTEM OVER RAYLEIGH FADING CHANNELIJCSES Journal
Multi Carrier Code Division Multiple Access (MC-CDMA) is a well known technique for high speed
wireless data transmission .Two advanced technology was included in the MC-CDMA structure, such as
orthogonal frequency division multiplex (OFDM) and the code division multiple access (CDMA),so that it
benefits from the robustness of OFDM against multipath environment and from the capability of multiuser
multiplexing services that is achieved via (CDMA) system. MC-CDMA is a multicarrier spread spectrum
system which is classified as the candidate scheme for future mobile radio systems. In this paper MCCDMA
system, with Rayleigh fading channel and 16QAM array modulation, was simulated to investigate
the effects of different parameters on the system performance, such as processing gain; number of paths;
number of users; interleaving; and coding ratio.MC-CDMA performances can be considerably improved
by proper selection of these parameters. As expected, results show that MC-CDMA has a better performance over CDMA system.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
A bi scheduler algorithm for frame aggregation in ieee 802.11 nijwmn
IEEE 802.11n mainly aims to provide high throughput, reliability and good security over its other previous
standards. The performance of 802.11n is very effective on the saturated traffic through the use of frame
aggregation. But this frame aggregation will not effectively function in all scenarios. The main objective of
this paper is to improve the throughput of the wireless LAN through effective frame aggregation using
scheduler mechanism. The Bi-Scheduler algorithm proposed in this article aims to segregate frames based
on their access categories. The outer scheduler separates delay sensitive applications from the incoming
burst of multi-part data and also decides whether to apply Aggregated - MAC Service Data Unit (AMSDU)
aggregation technique or to send the data without any aggregation. The inner scheduler schedules
the remaining (delay-insensitive, background and best-effort) packets using Aggregated-MAC Protocol
Data unit (A-MPDU) aggregation technique.
Performance of the MIMO-MC-CDMA System with MMSE EqualizationTamilarasan N
Multipath fading and spectral crowding are the
major challenges in dealing higher data rate in future
broadband wireless communication system. Multi-carrier
Modulation like Multicarrier code division multiple access
(MC-CDMA) can tackle the problem and provide higher data
rate for future wireless communication system. However,
through a frequency selective fading channel, the subcarriers
in MC-CDMA signal have different amplitude levels and phase
shifts which result in loss of the orthogonality among users
and generates Multiple access interference (MAI). To combat
the MAI, various amplitude and phase equalizing techniques
such as Maximum Ratio Combining (MRC), Equal Gain
Combining (EGC), Orthogonal Restoring Combining (ORC),
Threshold Orthogonal Restoring Combining or Minimum
Mean Square Error (MMSE) may be used. Out of these MMSE
offers better performance since the MMSE criterion is applied
independently on each subcarrier. Further improvement in
performance is possible through space–time block coding,
which offers maximum diversity gain and multiplexing gain.
This paper combines MC-CDMA with MMSE equalization
and space–time block coding which proves to be a powerful
physical layer solution in combating delay spread and inter
symbol interference (ISI).
Estimation and design of mc ds-cdma for hybrid concatenated coding in high sp...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This paper presents the design and performance comparison of a two stage
operational amplifier topology using CMOS and BiCMOS technology. This conventional op
amp circuit was designed by using RF model of BSIM3V3 in 0.6 μm CMOS technology and
0.35 μm BiCMOS technology. Both the op amp circuits were designed and simulated,
analyzed and performance parameters are compared. The performance parameters such as
gain, phase margin, CMRR, PSRR, power consumption etc achieved are compared. Finally,
we conclude the suitability of CMOS technology over BiCMOS technology for low power
RF design.
ABSTRACT : Performance enhancement of smart antennas versus their complexity for commercial wireless
applications. The goal of the study presented in this paper is to investigate the performance improvement
attainable using relatively simple smart antenna techniques when applied to the third-generation W-CDMA air
interface. Methods to achieve this goal include fixed multi beam architectures with different beam selection
algorithms (maximum power criterion, combined beams) or adaptive solutions driven by relatively simple direction
finding algorithms. After comparing these methods against each other for several representative scenarios, some
issues related to the sensitivity of these methods are also studied, (e.g., robustness to environment, mismatches
originating from implementation limitations, etc.). Results indicate that overall, conventional beam forming
seems to be the best choice in terms of balancing the performance and complexity requirements, in particular
when the problem with interfering high-bit-rate W-CDMA 3g users is considered.
Using the Channel State Information (CSI) at the transmitter is fundamental for the precoder
design in Multi-user Multiple Input Single Output (MU-MISO-OFDM) systems. In Frequency
Division Duplex (FDD) systems, CSI can be just available at the transmitter through a limited
feedback channel [1], where we assume that each user quantizes its channel direction with a
finite number of quantization bits. In this paper, we consider a scalar quantization (SQ) scheme
of the Channel Direction Information (CDI). Although vector quantization (VQ) schemes [2],
[3] still outperform this scalar scheme in terms of quantization error and Sum rate, the former
scheme suffers from an exponential search complexity and high storage requirements at the
receiver for high number of feedback bits.
Comparative Performance Assessment of V-Blast Encoded 8×8 MIMO MC-CDMA Wirele...pijans
The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system
for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM)
schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system
employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN
channel and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study
demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2-
rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance
utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission
Some of the key driving forces behind the transition from the UMTS based cellular system to the Long Term Evolution Advanced (LTE-A) are to improve the mean and the cell-edge throughput, improve the user fairness, and improve the quality of service (QoS) satisfaction for all users. In the latter system, relays appear as one of the most prominent enabler for improving the cell-edge user experience while increasing the system’s fairness.
In this white paper, we present the basics of relay deployments in LTE-A networks. Moreover, we analyze resource allocation problem for Relay Nodes (RN) deployments and present some of the solutions for improvement in system resource usage and QoS satisfaction. Afterwards, we introduce the capabilities of NOMOR’s LTE-A system level simulator and evaluate the performance of LTE-A relay systems under the described solutions.
PERFORMANCE OF MIMO MC-CDMA SYSTEM WITH CHANNEL ESTIMATION AND MMSE EQUALIZATIONTamilarasan N
The quality of a wireless link can be described by three basic parameters, namely transmission rate, transmission range
and transmission reliability. With the advent of multiple-input multiple-output (MIMO) assisted Multicarrier code
division multiple access (MC-CDMA) systems, the above-mentioned three parameters may be simultaneously
improved. The MC-CDMA combined with the MIMO technique, has become a core technology for future mobile radio
communication system. However, possible potential gain in spectral efficiency is challenged by the receiver’s ability to
accurately detect the symbol due to inter symbol interference (ISI). Multipath propagation, mobility of transmitter,
receiver and local scattering cause the signal to be spread in frequency, different arrival time and angle, which results in
ISI in the received signal. This will affect overall system performance. The use of MC-CDMA mitigates the problem of
time dispersion. However, still it is necessary to remove the amplitude and phase shift caused by channel. To solve this
problem, a multiple antenna array can be used at the receiver, not only for spectral efficiency or gain enhancement, but
also for interference suppression. This can be done by the, efficient channel estimation with strong equalization. This
paper proposes MIMO MC-CDMA system, Minimum mean square error (MMSE) equalization with pilot based
channel estimation. The simulation result shows improved Bit error rate (BER) performance when the sub carrier (SC)
and antenna configuration were increased
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
Iterative network channel decoding with cooperative space-time transmissionijasuc
One of the most efficient methods of exploiting space diversity for portable wireless devices is cooperative
communication utilizing space-time block codes. In cooperative communication, users besides
communicating their own information, also relay the information of other users. In this paper we
investigate a scheme where cooperation is achieved using two methods, namely, distributed space-time
coding and network coding. Two cooperating users utilize Alamouti space time code for inter-user
cooperation and in addition utilize a third relay which performs network coding. The third relay does not
have any of its information to be sent. In this paper we propose a scheme utilizing convolutional code based
network coding, instead of conventional XOR based network code and utilize iterative joint networkchannel
decoder for efficient decoding. Extrinsic information transfer (EXIT) chart analysis is performed to
investigate the convergence property of the proposed decoder.
Enabling relay selection in non-orthogonal multiple access networks: direct a...TELKOMNIKA JOURNAL
In this paper, we consider downlink non-orthogonal multiple access (NOMA) in which the relay selection (RS) scheme is enabled for cooperative networks. In particular, we investigate impact of the number of relays on system performance in term of outage probability. The main factors affecting on cooperative NOMA performance are fixed power allocations coefficients and the number of relay. This paper also indicate performance gap of the outage probabilities among two users the context of NOMA. To exhibit the exactness of derived formula, we match related results between simulation and analytical methods. Numerical results confirms that cooperative NOMA networks benefit from increasing the number of relay.
Performance of cluster-based cognitive multihop networks under joint impact o...TELKOMNIKA JOURNAL
In this paper, we evaluate outage probability (OP) of a cluster-based multi-hop protocol operating
on an underlay cognitive radio (CR) mode. The primary network consists of multiple independent
transmit/receive pairs, and the primary transmitters seriously cause co-channel interference (CCI) to the
secondary receivers. To improve the outage performance for the secondary network under the joint impact
of the CCI and hardware imperfection, we employ the best relay selection at each hop. Moreover, the
destination is equipped with multiple antennas and uses the selection combining (SC) technique to
enhance the reliability of the data transmission at the last hop. For performance evaluation, we first derive
an exact formula of OP for the primary network which is used to calculate the transmit power of the
secondary transmitters. Next, an exact closed-form expression of the end-to-end OP for the secondary
network is derived over Rayleigh fading channels. We then perform Monte-Carlo simulations to validate
the derivations. The results present that the CCI caused by the primary operations significantly impacts on
the outage performance of the secondary network.
Study on outage performance gap of two destinations on CR-NOMA networkTELKOMNIKA JOURNAL
Non-orthogonal multiple access (NOMA) and cognitive radio (CR) are promising to overcome spectral scarcity problem encountered in applications implementations in wireless communication. Especially, massive connectivity in such network is strict requirement in network deployment. This study aims to improve spectral efficiency at two secondary destinations by investigating a CR-NOMA network under situation of the perfect successive interference cancellation (SIC). We also derive the exact outage probability for secondary users. Furthermore, an approximate computation method is applied to indicate more insights. It is confirmed that the performance achieved together with performance gap among two users can be obtained due to different power allocation factors assigned to users.
Joint Fixed Power Allocation and Partial Relay Selection Schemes for Cooperat...TELKOMNIKA JOURNAL
In the future wireless systems, non-orthogonal multiple-access (NOMA) with partial relay selection scheme is considered as developing research topic. In this paper, dual-hop relaying systems is deployed for NOMA, in which the signals are communicated with the assistance of decode-and-forward (DF) scheme. This paper presents exact expressions for outage probability over independent Rayleigh fading channels, and two partial relay selection schemes are provided. Using analytical result and Monte-Carlo method, we introduce forwarding strategy selection for fixed user allocation and exactness of derived formula is checked. The presented simulations confirm the the advantage of such proposed NOMA, and the effectiveness of the proposed forwarding strategy.
Performance analysis for power-splitting energy harvesting based two-way full...TELKOMNIKA JOURNAL
Energy harvesting relay network is considered as the promising solution for a wireless
communication network in our time. In this research, we present and demonstrate the system performance
of the energy harvesting based two-way full-duplex relaying network over Nakagami-m fading
environment. Firstly, we propose the analytical expressions of the achievable throughput and outage
probability of the proposed system. In the second step, the effect of various system parameters on
the system performance is presented and investigated. In the final step, the analytical results are also
demonstrated by Monte-Carlo simulation. The numerical results demonstrated and convinced
the analytical and the simulation results are agreed with each other.
Tractable computation in outage performance analysis of relay selection NOMATELKOMNIKA JOURNAL
In recent years, using full-duplex (FD) transmission model provides enhanced bandwidth efficiency and improved performance for non-orthogonal multiple access (NOMA) system. However, lack of papers have investigated FD relay together with relay selection issue to improve performance of NOMA system. The problems in power allocation for two NOMA users satisfying fairness as well as relay selection strategy are studied in this paper. By considering the outage performance of proposed scheme with its vital result, general NOMA wireless networks can be developed for future networks due to its improved performance. Simulation results show that the relaying selection scheme can achieve a significant performance improvement by increasing required quantity of relay.
Wireless power transfer enabled NOMA relay systems: two SIC modes and perform...TELKOMNIKA JOURNAL
In this study, we deploy design and performance analysis in new system model using a relaying
model, energy harvesting, and non-orthogonal multi-access (NOMA) network. It is called such topology as
wireless powered NOMA relaying (WPNR). In the proposed model, NOMA will be investigated in two
cases including single successive interference cancellation (SIC) and dual SIC. Moreover,
the simultaneous wireless information and power transfer (SWIPT) technology can be employed to feed
energy to relays who intend to serve far NOMA users. In particular, exact outage probability expressions
are provided to performance evaluation. The results from the simulations are used to demonstrate
the outage performance of the proposed model in comparison with the current models and to verify correct
of derived expressions.
Exploiting Outage Performance of Wireless Powered NOMATELKOMNIKA JOURNAL
Considering a dual-hop energy-harvesting (EH) non-orthogonal multiple access (NOMA) relaying system, this paper consider novel relaying protocols based on time power switching-based relaying (TPSR) architecture for amplify-and-forward modes. We introduce novel system model relaying network with impacts of energy harvesting fractions and derive analytical expressions for outage probability for the information transmission link. It confirmed that right selection of power allocation for NOMA to obtain optimal performance. Theoretical results show that, in comparison with the conventional solutions, the proposed model can achieve optimal throughput efficiency for sufficiently small threshold SNR with condition of controlling time switching fractions and power splitting fractions appropriately in TPSR protocol. We also explore impacts of transmission distances in each hop, transmission rate, the other key parameters of TPSR to outage performance for different channel models. Simulation results are presented to corroborate the proposed methodology.
Security performance analysis for power domain NOMA employing in cognitive ra...journalBEEI
The power domain non-orthogonal multiple access (NOMA) technique introduces one of the fundamental characteristics and it exhibits the possibility of users to decode the messages of the other paired users on the same resources. In cognitive radio inspired NOMA (CR-NOMA), the base station (BS) has to serve untrusted users or users with different security clearance. This phenomenon raises a security threat particularly in such CR-NOMA. This paper develops a tractable analysis framework to evaluate the security performance of cooperative non-orthogonal multiple access (NOMA) in cognitive networks, where relay is able to serve two far NOMA users in the presence of external eavesdropper. In particular, we study the secrecy outage probability in a two-user NOMA system. This situation happens in practical the BS is pairing a legitimate user with another untrusted user. Main reason is that the non-uniform distribution in terms of trusted and untrusted users in the cell. By performing numerical results demonstrate the performance improvements of the proposed NOMA scheme in comparison to that of several situations in terms of different parameters. Furthermore, the security performance of NOMA is shown to verify the derived expressions.
Comparison study on secrecy probability of AF-NOMA and AF-OMA networksTELKOMNIKA JOURNAL
The strictly positive secrecy capacity (SPSC) performance is examined in a new design of non-orthogonal multiple access (NOMA) considered in this study. This system model employs Amplify-and-Forward (AF) relaying scheme to serve far users. In this scheme, a transmitter sends confidential signal to far users. It can be raised falling performance in the presence of an external eavesdropper in such NOMA system. With regard to orthogonal multiple access (OMA), performance of NOMA system model is compared. In particular, tradeoff the SPSC performance and transmit SNR is examined. In this study, the SPSC is evaluated as the secrecy metric to limit impacts of the practical passive eavesdropper in real scenario. It is confirmed that the secrecy performance of NOMA is significantly lower than OMA due to related parameters characterization in NOMA, and it should be controlled by varying related coefficients. As main results, both of NOMA and OMA against to impact of eavesdropper is studied in terms of analytically result and numerically result.
Joint impacts of relaying scheme and wireless power transfer in multiple acce...journalBEEI
This paper considers ergodic capacity of energy harvesting (EH) based cellular networks. Such a network employs non-orthogonal multiple access (NOMA) together with relaying scheme to serve two far users. In this system model, relay is facilitated power splitting (PS) protocol to implement energy harvesting (EH). To examine capacity, expressions of signal to noise ratio (SNR) need be computed to achieve capacity. Power allocation factors are different for two users in such system and hence performance gap happens to distinguish requirements for separated users. It can be confirmed that the proposed paradigm exhibits maximal achievable capacity in some scenarios of setting parameters. To confirm exactness of the analytical expressions and show advantages of the proposed EH-NOMA, simulation results are performed in terms of ergodic capacity.
Performance enhancement of wireless sensor network by using non-orthogonal mu...nooriasukmaningtyas
In this paper, we investigate a relaying wireless sensor network (WSN) with
the non-orthogonal multiple access (NOMA) and sensor node selection
schemes over rayleigh fading. Precisely, the system consists of two sensor
clusters, a sink node, and an amplify-and-forward (AF) relay. These sensors
applying the NOMA and sensor node selection schemes transmit the sensing
data from the sensor clusters via the relay to the sink. We derived the
expressions of outage probability and throughput for two sensor nodes. We
also provide numerical results to examine the behavior of the system. Finally,
we verify the validity of our analysis by using the monte-carlo simulation.
Performance Analysis for Parallel MRA in Heterogeneous Wireless NetworksEditor IJCATR
This paper analysis a different methods to find optimal path for services and power allocation to heterogeneous wireless network. Under heterogeneous wireless networks, a user can send data through a single or multi RATs (Radio Access Technology) simultaneously. The objective of this paper is to choose the optimal path for the services and power allocation to that bandwidth (BW) distributed joint allocation algorithm using Newton and modified Newton are adopted and the total system capacity compared. The analysis is done in Matlab and simulation results are compared. The numerical result shows that compare to Newton method, modified Newton method maximize the total system capacity.
COOPERATIVE COMMUNICATIONS COMBINATION DIVERSITY TECHNIQUES AND OPTIMAL POWER...ijaceeejournal
The main task of this article is to focus on the performance of cooperative MIMO relaying in terms of data rate and Power. Furthermore, compare these performances when using Maximum Ratio Combining (MRC) and equal gain combining (EGC).The average SNR improvement of MRC is typically about 5 dB better than with EGC and direct link.The preciseness of the derived closed form expression of optimum power allocation of the DF-based relaying system is demonstrated by simulation results.
Downlink beamforming and admissin control for spectrum sharing cognitive radi...acijjournal
n this paper, to detect the moving objects between frames in compressed video and to obtain the bes
t
compression video
and the noiseless video. We describe a video in which frames by classifying
macroblocks (MB), and describe motion estimation (ME), motion vector field (MV) and motion
compensation (MC). we propose to classify Macroblocks of each video frame into different
classes and use
this class information to describe the frame content based on the motion vector. MB class informatio
n
video applications such as shot change detection, motion discontinuity detection, Outlier rejection
for
global motion estimation. To reduc
e the noise and to improve the clarity of the compressed video by using
contrast limited adaptive histogram equalization (CLAHE) Algorithm
Downlink beamforming and admissin control for spectrum sharing cognitive radi...acijjournal
We investigate the
problem of multiuser downlink beam
-
forming and admission control considering a
scenario where licensed, or primary, users and cognitive radios, or secondary users, are transmittin
g
concurrently over the same band. The primary users share a common receiver
and the interference on this
receiver from secondary users should be strictly limited to a certain level. Each secondary link is
assumed
to have a minimum quality of service (QoS) requirement that should be satisfied together with the
interference limit co
nstraint, otherwise the secondary link is not admitted. Under those constraints,
downlink beam
-
forming and admission control for secondary users are investigated for two main
optimization objectives. First, we maximize the number of admitted secondary link
s. Second, we maximize
the sum throughput of the admitted secondary links. our main design objective is to minimize the tra
nsmit
power of the SU
-
transmitter while simultaneously targeting a lower
-
bound on the received signal
-
to
-
interference
-
plus
-
noise
-
rati
o(SINR) for the SU’s and imposing on upper limit on the interference power(IP)
at the PUs.
Exact Outage Performance Analysis of Amplify-and-forward-aware Cooperative NOMATELKOMNIKA JOURNAL
In this paper, new radio access scheme that combines Amplify-and-Forward (AF) relaying protocol and non-orthogonal multiple access (NOMA) system is introduced. In particular, different scenarios for fixed power allocation scheme is investigated. In addition, the outage probability of both weak and strong user is derived and provided in closed-form expressions. Such outage is investigated in high SNR scenario and comparison performance between these NOMA scenarios is introduced. Numerical simulations are offered to clarify the outage performance of the considered scheme if varying several parameters in the existing schemes to verify the derived formulas.
Distributed Spatial Modulation based Cooperative Diversity Schemeijwmn
: In this paper, a distributed spatial modulation based cooperative diversity scheme for relay
wireless networks is proposed. Where, the space-time block code is exploited to integrate with distributed
spatial modulation. Therefore, the interested transmission scheme achieves high diversity gain. By using
Monte-Carlo simulation based on computer, we showed that our proposed transmission scheme outperforms
state-of-the-art cooperative relaying schemes in terms bit error rate (BER) performance.
Similar to Outage and throughput performance of cognitive radio based power domain based multiple access (20)
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
In this paper, snake optimization algorithm (SOA) is used to find the optimal gains of an enhanced controller for controlling congestion problem in computer networks. M-file and Simulink platform is adopted to evaluate the response of the active queue management (AQM) system, a comparison with two classical controllers is done, all tuned gains of controllers are obtained using SOA method and the fitness function chose to monitor the system performance is the integral time absolute error (ITAE). Transient analysis and robust analysis is used to show the proposed controller performance, two robustness tests are applied to the AQM system, one is done by varying the size of queue value in different period and the other test is done by changing the number of transmission control protocol (TCP) sessions with a value of ± 20% from its original value. The simulation results reflect a stable and robust behavior and best performance is appeared clearly to achieve the desired queue size without any noise or any transmission problems.
Improving the detection of intrusion in vehicular ad-hoc networks with modifi...TELKOMNIKA JOURNAL
Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
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Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
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Outage and throughput performance of cognitive radio based power domain based multiple access
1. TELKOMNIKA Telecommunication, Computing, Electronics and Control
Vol. 18, No. 2, April 2020, pp. 579~586
ISSN: 1693-6930, accredited First Grade by Kemenristekdikti, Decree No: 21/E/KPT/2018
DOI: 10.12928/TELKOMNIKA.v18i2.12731 579
Journal homepage: http://journal.uad.ac.id/index.php/TELKOMNIKA
Outage and throughput performance of cognitive radio based
power domain based multiple access
Dinh-Thuan Do, Chi-Bao Le
Faculty of Electronics Technology, Industrial University of Ho Chi Minh City (IUH), Vietnam
Article Info ABSTRACT
Article history:
Received Mar 24, 2019
Revised Jan 13, 2020
Accepted Feb 8, 2020
This paper considers power domain based multiple access (PDMA)
in cognitive radio network to serve numerous users who intend to multiple
access to core network. In particular, we investigate the effect of signal
combination scheme equipped at PDMA end-users as existence of direct link
and relay link. This system model using relay scheme provides performance
improvement on the outage probability of two PDMA end-users. We first
propose a simple scheme of fixed power allocation to PDMA users who
exhibit performance gap and fairness. Inspired by PDMA strategy, we then
find signal to noise ratio (SNR) to detect separated signal for each user.
In addition, the exact expressions of outage probability are derived in
assumption that receiver can cancel out the interference completely with
successive interference cancellation (SIC). By exploiting theoretical and
simulation results, both considered combination schemes (Maximal Ratio
Combining (MRC) and Selection Combining (SC) can achieve improved
performance of two PDMA users significantly.
Keywords:
MRC
Outage probability
Power domain based multiple
access
SC
This is an open access article under the CC BY-SA license.
Corresponding Author:
Dinh-Thuan Do,
Faculty of Electronics Technology,
Industrial University of Ho Chi Minh City (IUH),
Ho Chi Minh City, Vietnam.
Email: dodinhthuan@iuh.edu.vn
1. INTRODUCTION
Recently, cognitive radio (CR) has been attracted considerable attention due to its ability to
improved spectrum utilization [1]. Achieving advantage of CR to the fifth generation (5G) mobile networks,
the primary network containing base station (BS) and BS-served mobile users and the secondary network
including two kinds of users (mobile users non-served by the BS) can occupy resource in a same licensed
band [2]. Unfortunately, the primary users are under impact of interference from the secondary users located
in such a underlay approach. Therefore, it is required to limit the interference to below a certain level to
guarantee system performance [3]. In overlay CR, the channels can be selected dynamically without
inter-user interference while channel is decided under certain interference constraint in underlay CR.
The other is an attractive solution, power domain based multiple access (PDMA), and it is proposed for 5G
wireless communications. In PDMA, multiple users are permitted to transmit superimposed signals by
employing the same carrier and the same time slot. In real practice, secure issue is challenge in above
technologies to enhance spectral efficiency related to spectrum sharing [4]. Although secondary user (SU)
can access to a spectrum of a primary user (PU), such SU in cognitive radio networks (CRNs) may meet
wiretap legitimate signals due to without appropriate spectrum management policies. Accordingly, secure
transmission quality of primary systems in cognitive radio networks (CRNs) using several models have been
2. ISSN: 1693-6930
TELKOMNIKA Telecommun Comput El Control, Vol. 18, No. 2, April 2020: 579 - 586
580
investigated [5–7]. Fortunately, relaying network provides extended coverage with reasonable outage
performance [8-13]. Such relay scheme is proposed to combine with PDMA technology to introduce
cooperative PDMA [14, 15]. It is proposed to guarantee the transmit quality of massive users with poor
channel [16] and allow more users to access into one spectrum resource block at the same time.
With regard to higher spectrum efficiency, new trend of PDMA and CR is introduced as
CR-inspired PDMA as in [17]. The authors studied different receiving qualities of two PDMA systems in two
schemes, such as fixed power allocation PDMA and CR-inspired PDMA. To guarantee the channel quality of
a user who meets a poor channel condition, the CR-inspired PDMA is recommended [17]. To evaluate
system performance, the CR-inspired PDMA indicated better fairness in term of spectrum allocation
compared with the fixed-power-allocation PDMA. In other work, the power allocation scheme is developed
for two secondary user (SUs) existing in the PDMA-enabled underlay CR (CR PDMA). Such CR PDMA is
deploy to enhance the spectral efficiency by using interference cancellation [18]. Thus, to greatly improve
the spectrum utilization, PDMA is proposed to integrate into underlay CR with power constraints.
Motivated by [19-25] this paper analyzes the outage and throughput performance by applying
the PDMA protocol in a CR network. In this situation, we considers system performance in a downlink
communication scenario. The network is composed of a pair of PDMA users, a primary network containing
base station (BS) and user while the source in secondary network need a helping relay to forward signal to far
user. We assume that all end-users operate in the PDMA transmission protocol at the same time. The main
contributions are summarized as follows.
- We propose a new underlay CR PDMA-enabled transmission and provide performance gap of two PDMA
users to satisfy the quality of service (QoS) requirements of such CR PDMA system.
- We formulate exact outage probability for two PDMA users while satisfying a given fixed power allocation
factors. Then, we confirm outage performance and corresponding throughput in numerical results.
- We analyze the overall network performance, study the problem of fixed power allocation under
the constraint of the system total power, and indicate numerical method to solve the optimal problem of
throughput performance.
The rest of the paper is organized as follows. Section II presents a PDMA-enabled CR system with
a pair of PDMA end-users are served by both sources in primary network and secondary network, secondary
source using one relay to serve far PDMA user. In Section III, we extend our study to a situation with fixed
power allocation to derive outage probability and corresponding throughput of overall system. Simulation
results are shown in Section IV, and conclusions are presented in Section V.
2. SYSTEM MODEL AND CALCULATIONS OF SNR
In this article, we consider a communication with CR PDMA model as shown in Figure 1.
This model consists primary network containing a base station (BS) and far PDMA user, a secondary
network containing source, relay R and far PDMA user. All entities in the network are equipped with single
antenna and the communication of primary and secondary system operates in using the PDMA transmission
principles. Assuming that both the relay and two PDMA users can estimate the secondary and primary
channels by some learning processes in the actual situation, they can be aware of the channel state
information (CSI) of all the channels perfectly. In addition, all channels are assumed to be quasi-static
Rayleigh fading, where the channel coefficients are constant for each transmission block but vary
independently between different blocks.
Figure 1. System model of joint CR and PDMA
3. TELKOMNIKA Telecommun Comput El Control
Outage and throughput performance of cognitive radio based power domain based … (Dinh-Thuan Do)
581
For the operation of helping relay in secondary systems, relay may receive the synthetic message
from the primary source S1 and signal from the secondary source S2. We denote noise terms
2 2 2 2 2 2
, 1 , 2 1, 1 2, 2R R U R U S U S U = = = = = and 1 2
2 2 2
S S RP P P
= = = . SNR at relay to detect x2:
2
2,
, 2 2
1,
.
1
S R
R x
S R
h
h
=
+
(1)
We compute SNR at relay to detect x1
2
, 1 1, .R x S Rh = (2)
It can be found SNR at U1 to detect x2
2
2 , 1
1, 2 2
1 , 1
.
1
R U
RU x
R U
a h
a h
=
+
(3)
It need be computed SNR at U1 to detect x1 as
2
1, 1 1 , 1 .RU x R Ua h = (4)
It can be calculated SNR at U2 to detect x2 as
2
2 , 2
2, 2 2
1 , 2
.
1
R U
RU x
R U
a h
a h
=
+
(5)
In direct link of primary network in such CR PDMA, SNR at U1 to detect x1 is given by;
2
1 1, 1 1, 1 .S U x S Uh = (6)
Also, in direct link of secondary network in such CR PDMA, SNR at U1 to detect x2 is computed by
2
2 2, 2 2, 2 .S U x S Uh = (7)
3. OUTAGE PROBABILITY AND THROUGHPUT ANALYSIS
In this section, we investigated the outage behavior for the CR PDMA downlink cooperative
network with perfect CSI. To this end, exact expressions for the outage probability is studied first. In order to
best throughput and better understand the behavior of the network, a numerical method is applied to show
throughput, while fairness among PDMA users satisfied, regime. We use Maximal Ratio Combining (MRC)
to further process signal at U1, U2 as existences of direct link and relay link between the BS and PDMA
end-users.
3.1. Scheme I: maximal ratio combining (MRC)
At each destination, two links are combined and hence SNR in such MRC case can be expressed at
U1, U2 respectively as;
2 2
1 1, 1 1 , 1 ,MRC
U S U R Uh a h = + (8)
4. ISSN: 1693-6930
TELKOMNIKA Telecommun Comput El Control, Vol. 18, No. 2, April 2020: 579 - 586
582
and
2
2 2 , 2
2 2, 2 2
1 , 2
.
1
R UMRC
U S U
R U
a h
h
a h
= +
+
(9)
we set new variable
( )
2
2 2 1a a
=
−
then, the outage probability at user U1 can be given by;
( ) ( ) ( )
2 31
1 1 1 , 1 1 , 1 1 1 1, 1 1Pr Pr Pr , .MRC
U U R x R x S U x
A AA
P = + (10)
proposition 1: the closed-form expression of outage probability at user U1 can be given by
1 1 1
1 1 1 1
1 U1 1 1 ,
m m m
S R S R S Ud d d
UP e e e
− − −
− − −
= + − −
(11)
where
1 11 1
1 1 1 11 1 1 1
1
1 1
U1
1 1 1 1
1 1
m mm m
RU S URU S U
a
m
a d dd a dS U
m m
S U RU
d
e e e
d d a
− −− −
−− −− −
− −
= − − −
−
Proof:
We have following equation
( )1 1 1
2 2 2
1 1
1, 1 1 , 1 , 1
1
Pr
Pr , .
MRC
U
S U R U R U
A
h a h h
a
=
= −
(12)
Then, it can be further expressed as
( )
1
1
2 2
1, 1 , 1
1 11 1
1 1 1 11 1 1 1
1
1 1
0
1
1 1
1 1 1 1
1 1 .
S U R U
m mm m
RU S URU S U
a
h h
a
m
a d dd a dS U
m m
S U RU
A F a x f x dx
d
e e e
d d a
− −− −
− − −− −
− −
= −
= − − −
−
(13)
Then, two remaining component can be obtained as
( )
1
1
2 , 1 1Pr
,
m
S R
R x
d
A
e
−
−
=
=
(14)
and
( )
1 1
1 1 1
3 , 1 1 1 1, 1 1Pr ,
1 1 .
m m
S R S U
R x S U x
d d
A
e e
− −
− −
=
= − −
(15)
This is end of the proof.
Similarly, outage probability at user U2 can be computed by
5. TELKOMNIKA Telecommun Comput El Control
Outage and throughput performance of cognitive radio based power domain based … (Dinh-Thuan Do)
583
( ) ( ) ( )
2 31
2 2 2 , 2 2 , 2 2 2 2, 2 2Pr Pr Pr , .MRC
U U R x R x S U x
B BB
P = + (16)
Proposition 2: The closed-form expression of outage probability at user U2 can be given by:
( )
( )
2 2
2 2 2 22
2 2
02 2 2 12 1
1
1 1 ,
!
m m m
RU S R S U
n m
d d dS R
U n m mm
n S R S RRU
de
P e e e
d dn d a
− − −
−−− −
− −−
=
− = − − + − −
+
(17)
where
( )
( )
( ) ( )( )
( )
( ) ( )
1
2 1 11
1 1 1
2 1
0
1 1
Ei Ei
1 ! 1 1
n nn k kn
k
e a e
n n n n k
+ + +
=
− + −
= − +
+ + + −
, 2 1 2
m
RUa d −
= ,
2
1
1 2 2 2
1
m m
RU S Ua d d
− −
= − − , 2
1
1 2 2
m
S U
a
a d −
= − and
2
2
2 2 22
1 1
2
2 1 2
m mm
S U S RS R
m
d ddS R
m m
S R S R
d
e e
d d
− −−
− − +−
− −
= −
+
Proof: see in appendix
3.2. Scheme II: selection combining (SC)
We consider outage performance of each destination by using Selection Combining (SC) as;
( ) ( )1 1 1, 1 1 , 1 1 1, 1 1
2 2 2
1 1 1
1, 1 1, , 1
1
Pr 1 Pr ,
Pr 1 Pr , .
U S U x R x RU x
S U S R R U
OP
h h h
a
= −
= −
(18)
Then, it is rewritten as;
( ) ( ) ( )
1
2 2 2
1, 1 1, , 1
1 1
1
1 11
1 1 1 1 1 1 1 11 1
1
0
1 1 1 1 1
1
1 .
S U S R R U
m m m m mm
S R RU S R RU S US U
U h h h
a
d d a d d a dd
OP f x dx f x f y dxdy
e e e
− − − − −−
− + − + +−
= −
= − − +
(19)
Consider signal at the second destination, outage performance of U2 is;
( ) ( )
( ) ( )
2 2, 2 2 , 2 2 2, 2 2
2 2 2 2
2 2 2
2, 2 2, 1, , 2
2 2 1
Pr 1 Pr ,
Pr 1 Pr 1 , .
U S U R x RU x
S U S R S R R U
OP
h h h h
a a
= −
= − + −
(20)
Next, it can be rewritten as;
( ) ( ) ( )
( )
( )
( )
( ) ( )
2
2 2 2 2
2, 2 1, 2, , 2
2 2
2 2 1
2 22
2 2 2 2 1 2 2 2 2 1 2 22 2
2
0 0
1
1 1 1 1 1
2
2 1 2
1
1
S U S R S R R U
m m m m mm
S R RU S R RU S US U
U h h h h
x
a a
m
d d a a d d a a dd S R
m m
S R S R
OP f x dx f x f x dxdy f z dz
d
e e e
d d
− − − − −−
+
−
− − + − + +− − −
− −
= −
= − − −
+
.
(21)
6. ISSN: 1693-6930
TELKOMNIKA Telecommun Comput El Control, Vol. 18, No. 2, April 2020: 579 - 586
584
Then, we further examine optimal throughput in case of fixed data rates are known. Such system throughput
can be given by
( ) ( )1 1 2 21 1U UP R P R = − + − (22)
4. NUMERICAL RESULTS
In this section, our parameters are shown to simulate, i.e. power allocation factors 1 2
0.2, 0.8a a= = ,
target rates 1
2R = , 2
0.5R = , distances 1 1mS Rd = , 2 1mS Rd = , 1 2mRUd = , 2 4mRUd = , 1 1 1 1S U S R RUd d d= +
and 2 2 2 2S U S R RUd d d= + , path-loss exponent 2m = . Figure 2 shows impact of target rates on outage
performance. In addition, higher transmit SNR at the source node S1, S2 results in better outage performance.
To comparison, outage performance of U1 for scheme I is better than that of scheme II. While performance
of U2 is similar for two considered schemes.
Figure 3 illustrates that increasing target rates make our system meet outage event. This figure
confirms that higher transmit SNR at source leads to better performance. It can be seen slight performance
gap for user U2 as comparing two schemes. It can be found highest throughput at optimal target rate as in
Figure 4. This result confirms that optimal throughput can be achieved by numerical method. It can be seen
slight performance gap as comparing two schemes.
Figure 2. Outage performance versus transmit SNR
in CR PDMA
Figure 3. Outage performance versus target rates of
CR PDMA
Figure 4. Throughput performance of CR PDMA versus target rates
7. TELKOMNIKA Telecommun Comput El Control
Outage and throughput performance of cognitive radio based power domain based … (Dinh-Thuan Do)
585
5. CONCLUSION
In this paper, we studied the fixed power allocation scheme design for robust and guarantee fairness
in communication of CR PDMA systems. Each source in each network of CR can serve its own signal
forwarding to relay and then the superimposed signal can be received at the PDMA end users. Such model
was employed for serving multiple access in downlink. Simulation results revealed that the considered CR
PDMA system employing the proposed fixed power allocation scheme can guarantee fairness in PDMA
significantly. With respect to specific data rate, it can be achieved highest throughput. Furthermore, our
results confirmed the outage small performance gap among two PDMA users of the proposed scheme with
respect to varying transmit SNR and revealed the impact of various system parameters on performance.
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8. ISSN: 1693-6930
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APPENDIX
It can be computed each component in such outage of U2 as
2 2
12 2 2 2
1
2
2 22 , 22
1 2, 2 , 22
1 , 2
1
1
20
Pr ,
1
1
1
m m m
RU RU S U
R U
S U R U
R U
a xx
a xd d d
m
RU
a h
B h h
a h
e e e dx
d
− − −
− − − − +
−
= −
+
= − −
(A.1)
new variable is set as 1 1y a x= + then it can be rewritten as
( )
( )
( )
22 1 1
2 2 1 2 2 2 1 2 2 1
2
111 1
1
022 1 12 1
11
!
m m m m
S U RU S U S U
a yy yna a
d a d d a y d a yn
m nm
nRU RU
e
e e e dy y e dy
d n d a
− − − −
−−+ +− − −
− −
=
−
= =
(A.2)
where 2
1
1 2 2 2
1
m m
RU S Ua d d
− −
= − − , 2
1
1 2 2
m
S U
a
a d −
= − and 2 1 2
m
RUa d −
= . Note that it can be further
calculated new equation by using Binomial theorem. We set
1
z
y
= and it can be obtained that
( )
( )
( ) ( )( )
( )
( ) ( )
2
2 2 1
1
1
1
2 2
1
1
2 1 11
1 1 1
1
0
1
1 1
Ei Ei
1 ! 1 1
m
S U
a z
d a
n
a
n nn k kn
k
e dz
z
e a e
n n n n k
−
−
+
+
+ + +
=
=
− + −
= − +
+ + + −
(A.3)
where (A.3) can be obtained. Substituting (A.2) and (A.3) into (A.1), is written as
( ) ( )
( )
( ) ( )( )
( )
( ) ( )
1
2
2 1 11
1 1 1
1 11
0 02
1 1 1
1 Ei Ei
1 ! 1 1!
m
RU
n n nn k kn
d
n
n k
e a e
B e e
n n n n kn
−
+ + +−
+
= =
− − + −
= − − − +
+ + + −
(A.4)
Next, it can be obtained
( )
( ) ( )
( )
2
2
2 2
1, 2,
2
2 , 2 2
2
2 2 10
1
Pr
m
S R
S R S R
R x
m
dS R
m mh h
S R S R
x
B
d
f x f y dxdy e
d d
−
− −
− −
+
=
= =
+
(A.5)
and
𝐵3 = (|ℎ 𝑠2,𝑅|
2
<
𝛾2
𝜌
(𝜌|ℎ 𝑆1,𝑅|
2
+ 1) , |ℎ 𝑠2,𝑈2|
2
<
𝛾2
𝜌
)
= 1 − 𝑒
−
𝛾2
𝑑 𝑆2𝑈2𝜌
−𝑚
−
𝑑 𝑆2𝑅
−𝑚
𝑑 𝑆2𝑅
−𝑚 + 𝑑 𝑆1𝑅
−𝑚 𝛾2
(𝑒
𝛾2
𝑑 𝑆2𝑅
−𝑚 𝜌
− 𝑒
−𝛾
2(
1
𝑑 𝑆2𝑈2
−𝑚 𝜌
+
1
𝑑 𝑆2𝑅
−𝑚 𝜌
)
) (A.6)