This document summarizes a research paper that investigates reducing peak-to-average power ratio (PAPR) in an MC-CDMA system using partial transmit sequence (PTS) technique with a suboptimal combination algorithm. The paper simulates a downlink MC-CDMA system with BPSK and QPSK modulation under varying system parameters like number of users and phase sequences. Results show the complementary cumulative distribution function (CCDF) of PAPR for the original and PTS-processed signals. Using PTS with 4, 8, or 16 phase sequences provides 1dB, 2dB, and 4.2dB of PAPR reduction respectively compared to the original signal for a 8-user BPSK modulated MC-CD
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
PAPR REDUCTION OF OFDM SIGNAL BY USING COMBINED HADAMARD AND MODIFIED MEU-LAW...IJCNCJournal
Orthogonal frequency division multiplexing (OFDM) is a technique which gives high quality of service (QOS) to the users by mitigating the fading signals as well as high data rates in multimedia services. However, the peak-to-average power ratio (PAPR) is a technical challenge that reduces the efficiency of RF power amplifiers. In this paper, we propose the combined Hadamard transform and modified meu-law companding transform method in order to lessen the effects of the peak-to-average power ratio of the
OFDM signal. Simulation results show that the proposed scheme reduces PAPR compared to other companding techniques as well as the Hadamard transform technique when used on its own.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
PAPR REDUCTION OF OFDM SIGNAL BY USING COMBINED HADAMARD AND MODIFIED MEU-LAW...IJCNCJournal
Orthogonal frequency division multiplexing (OFDM) is a technique which gives high quality of service (QOS) to the users by mitigating the fading signals as well as high data rates in multimedia services. However, the peak-to-average power ratio (PAPR) is a technical challenge that reduces the efficiency of RF power amplifiers. In this paper, we propose the combined Hadamard transform and modified meu-law companding transform method in order to lessen the effects of the peak-to-average power ratio of the
OFDM signal. Simulation results show that the proposed scheme reduces PAPR compared to other companding techniques as well as the Hadamard transform technique when used on its own.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
On the Performance Analysis of Multi-antenna Relaying System over Rayleigh Fa...IDES Editor
In this work, the end-to-end performance of an
amplify-and-forward multi-antenna infrastructure-based relay
(fixed relay) system over flat Rayleigh fading channel is
investigated. New closed form expressions for the statistics of
the received signal-to-noise ratio (SNR) are presented and
applied for studying the outage probability and the average
bit error rate of the digital receivers. The results reveal that
the system performance improves significantly (roughly 3 dB)
for M=2 over that for M=1 in both low and high signal-tonoise
ratio. However, little additional performance
improvement can be achieved for M>2 relative to M=2 at high
SNR.
Performance and Analysis of OFDM Signal Using Matlab SimulinkIJMER
Multi-carrier modulation is an attractive technique for fourth generation .OFDM is based on
multicarrier modulation technique. In OFDM system the bit stream is divided into many different sub
channels. An efficient and distortionless scheme for peak power reduction in OFDM is proposed. In this
paper, a set of mapping where the actual transmit signal is selected. From this set of signal reduced
PAPR. Simulation results are shown. The lowest PAPR is compared with conventional work. It is also
compared BER to SNR and best result is achieved.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
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.
SLM-PTS BASED PAPR REDUCTION TECHNIQUES IN OFDM SYSTEMHariniChaganti1
Signals, which were initially sent in the analog domain, are being sent more and more in the digital domain these days. For better transmission, even single–carrier waves are being replaced by multi–carriers. Multi-carrier
systems like OFDM are now – a – days being implemented commonly. In the OFDM system,
orthogonally placed subcarriers are used to carry the data from the transmitter end to the receiver end. The presence of a guard band in this system deals with the problem of ISI and noise is minimized by a larger number of sub–carriers. But the large Peak– to –Average Power Ratio of these signal have some undesirable effects on the system. The Peak-to-Average Power Ratio is the ratio between the maximum power and average power of a complex passband signal. It causes many disadvantages like band-in and band-out variation, low signal to quantization noise ratio, low efficiency of power amplifier, etc. Hence, it is necessary to reduce PAPR in OFDM for its efficient use.
In this project, the main objective is to study the basics of an OFDM System and analyze and
simulate various methods such as clipping and filtering, selected mapping, Partial transmit sequence
to reduce the PAPR in the system and compare these techniques with and without PAPR reduction to
obtain an efficient technique so that this system can be used more commonly and effectively.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Design of Low Voltage Low Power CMOS OP-AMPIJERA Editor
Operational amplifiers are an integral part of many analog and mixed signal systems. As the demand for mixed
mode integrated circuits increases, the design of analog circuits such as operational amplifiers in CMOS
technology becomes more critical. This paper presents a two stage CMOS operational amplifier, which operates
at ±1.8V power supply using TSMC 0.18um CMOS technology. The OP-AMP designed exhibit unity gain
frequency of 12.6 MHz, and gain of 55.5db with 300uw power dissipation. The gain margin and phase margin
of OP-AMP is 45˚ and 60˚ respectively. Design and simulation has been carried out in P Spice tool.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
On the Performance Analysis of Multi-antenna Relaying System over Rayleigh Fa...IDES Editor
In this work, the end-to-end performance of an
amplify-and-forward multi-antenna infrastructure-based relay
(fixed relay) system over flat Rayleigh fading channel is
investigated. New closed form expressions for the statistics of
the received signal-to-noise ratio (SNR) are presented and
applied for studying the outage probability and the average
bit error rate of the digital receivers. The results reveal that
the system performance improves significantly (roughly 3 dB)
for M=2 over that for M=1 in both low and high signal-tonoise
ratio. However, little additional performance
improvement can be achieved for M>2 relative to M=2 at high
SNR.
Performance and Analysis of OFDM Signal Using Matlab SimulinkIJMER
Multi-carrier modulation is an attractive technique for fourth generation .OFDM is based on
multicarrier modulation technique. In OFDM system the bit stream is divided into many different sub
channels. An efficient and distortionless scheme for peak power reduction in OFDM is proposed. In this
paper, a set of mapping where the actual transmit signal is selected. From this set of signal reduced
PAPR. Simulation results are shown. The lowest PAPR is compared with conventional work. It is also
compared BER to SNR and best result is achieved.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
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.
SLM-PTS BASED PAPR REDUCTION TECHNIQUES IN OFDM SYSTEMHariniChaganti1
Signals, which were initially sent in the analog domain, are being sent more and more in the digital domain these days. For better transmission, even single–carrier waves are being replaced by multi–carriers. Multi-carrier
systems like OFDM are now – a – days being implemented commonly. In the OFDM system,
orthogonally placed subcarriers are used to carry the data from the transmitter end to the receiver end. The presence of a guard band in this system deals with the problem of ISI and noise is minimized by a larger number of sub–carriers. But the large Peak– to –Average Power Ratio of these signal have some undesirable effects on the system. The Peak-to-Average Power Ratio is the ratio between the maximum power and average power of a complex passband signal. It causes many disadvantages like band-in and band-out variation, low signal to quantization noise ratio, low efficiency of power amplifier, etc. Hence, it is necessary to reduce PAPR in OFDM for its efficient use.
In this project, the main objective is to study the basics of an OFDM System and analyze and
simulate various methods such as clipping and filtering, selected mapping, Partial transmit sequence
to reduce the PAPR in the system and compare these techniques with and without PAPR reduction to
obtain an efficient technique so that this system can be used more commonly and effectively.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Design of Low Voltage Low Power CMOS OP-AMPIJERA Editor
Operational amplifiers are an integral part of many analog and mixed signal systems. As the demand for mixed
mode integrated circuits increases, the design of analog circuits such as operational amplifiers in CMOS
technology becomes more critical. This paper presents a two stage CMOS operational amplifier, which operates
at ±1.8V power supply using TSMC 0.18um CMOS technology. The OP-AMP designed exhibit unity gain
frequency of 12.6 MHz, and gain of 55.5db with 300uw power dissipation. The gain margin and phase margin
of OP-AMP is 45˚ and 60˚ respectively. Design and simulation has been carried out in P Spice tool.
Using Social network in Higher Education A case Study on the University of Pa...IJERA Editor
The users which are using social networking sites nowadays by various strata of society such as students,
teachers, engineers, housewives and elderly people are increasing. So the goal of this paper is to invest social
networking in education especially at the universities.
Student spending more time on the social networking sites than on the e-learning programs, so social
networking can be used in a useful way to support e-learning. 54% of people who were surveyed about the
usage of social Networks said they used Facebook daily while 9% used MOODLE.
So this paper uses the social networks for e-learning as a case study on the university of Palestine.
To find effects of GMAW parameters on Mechanical Properties of Aluminum AlloysIJERA Editor
The present research aims to investigate the effects of Gas Metal Arc Welding (GMAW) on the mechanical
properties of different grades of aluminum alloys. GMAW is the most common method of joining aluminum
alloys used in various industrial processes. It replaces the Tungsten Inert Gas (TIG) method of providing equally
high quality of joints with a much higher performance. Aluminum alloys under consideration for this
experiment will be from 6XXX series, consisting of Silicon and Magnesium as main alloying elements. Weld
joints Will be produced with the help of a Gas Metal Arc Welding (GMAW) process. The Hardness, Tensile
strength, yield stresses and elongation will be the mechanical properties to be obtained. As aluminum alloys
show large micro structural changes after welding it is necessary to know about the effect of welding parameters
on the mechanical properties of weldements as too high welding current and too high welding speed will result
in high heat input and weakening of weld profile so a balance is need to be struck between welding parameters
and mechanical properties. Scattering Electron Microscopy (SEM) technique will be used to analyze micro
Development of agricultural e-commerce framework for India, a strategic appro...IJERA Editor
This study is aimed to put forward an inclusive and pertinent e-commerce framework that serves as a platform
for the development and improvement of rural agriculture sector in India; which plays a major role towards
socioeconomic development of rural livelihoods along with food security and poverty reduction. The main
approach used was to critically review and understand the National Informatics Centre (NIC) and the Ministry of
Agriculture policies. In general, these policies emphasize on promoting IT based information kiosks, establishing
gyan chaupals (Knowledge centers) in villages, construction of Agri-India knowledge portal. Next, the
challenges and information gaps were identified and translated in the form of agriculture e-commerce framework
which can be used to build an e-commerce application.
Power Quality Enhancement in Wind Connected Grid System Interface Based On St...IJERA Editor
Wind energy has become one of the significant alternative renewable energy resources because of its abundance
and the strong drive for its commercialization. Dynamic electric load variations and wind velocity excursions
cause excessive changes in the prime mover kinetic energy and the corresponding electrical power injected into
the AC grid utility system. In this paper, a scheme based on the low cost static switched filter compensator
(SSFC) is presented for voltage sag/swell compensation, power factor improvement in distribution grid
networks with the dispersed wind energy interface. The SSFC scheme is based on an intermittent switching
process between two shunt capacitor banks to be one of them in parallel with the capacitor of a tuned arm filter.
Two regulators based on a tri- loop dynamic error driven inter-coupled weighted modified proportional-integralderivative
(PID) controller which is used to modulate the PWM.
The Static Switched Filter Compensation (SSFC) compensation scheme which enhances the system
power quality has been fully validated using MATLAB–Simulink. The effectiveness of this compensation
scheme approach is demonstrated using a study case of 3 bus system. Simulation results show that there is
improvement in harmonics reduction, voltage sag/swell compensation, power factor improvement at generator
bus, load bus, and infinite bus respectively
A typical Realization of the process with linear recovery of AldosteroneIJERA Editor
Hypercortisolism as a sign of hypothamamus-pituitary-adrenocortical (HPA) axis overactivity and sleep EEG
changes are frequently observed in depression. Closely related to the
HPA axis is the renin-angiotensin-aldosterone system (RAAS) as 1. adrenocorticotropic hormone (ACTH) is a
common stimulus for cortisol and aldosterone, 2. cortisol release is suppressed by mineralocorticoid receptor
(MR) agonists 3. angiotensin II (ATII) releases CRH and vasopressin from the hypothalamus. The first passage
time and the bounds of the survival functions for the application are also obtained
A Positive Buck Boost Converter with Mode Select Circuit and Feed Forward Tec...IJERA Editor
The portable devices development of semiconductor manufacturing technology, conversion efficiency, power
consumption, and the size of devices have become the most important design criteria of switching power
converters. For portable applications better conveniences extension of battery life and improves the conversion
efficiency of power converters .It is essential to develop accurate switching power converters, which can reduce
more wasted power energy. The proposed topology can achieve faster transient responses when the supply
voltages are changed for the converter by making use of the feed forward network .With mode select circuit the
conduction & switching losses are reduced the positive buck–boost converter operate in buck, buck–boost, or
boost converter. By adding feed-forward techniques, the proposed converter can improve transient response
when the supply voltages are changed. The designing, modeling & experimental results were verified in
MATLAB/ Simulink. The fuzzy logic controller is used as controller.
Static & Thermal Analysis of Positive Multiple Friction Plate using FEA PackageIJERA Editor
Clutch is a mechanical device, which is used to engage or disengage the source of power from the rest of the
power transmission system at the operator’s will. The clutch can connect or disconnect the driving shaft from
the driven shaft when necessary. Clutches are designed to transfer maximum torque with minimum heat
generation. During engagement and disengagement the two clutch discs has the sliding motion between them.
The project contains that designing and analysis of two positive multi friction plates.
For the designing of the friction plates 3d modeling software used and for the analysis ansys package is used.
In the analysis part the two models are analyzed with different materials by conducting two types of analysis
which are structural and thermal.
Structural analysis is done to find out the stress values and the thermal analysis done to find out the temperature
distribution on the model. By these two analysis results we are suggesting the best material to the effective
model of the multiple friction plate.
Reduced Test Pattern Generation of Multiple SIC Vectors with Input and Output...IJERA Editor
In recent years, the design for low power has become one of the greatest challenges in high-performance very
large scale integration (VLSI) design. Most of the methods focus on the power consumption during normal mode
operation, while test mode operation has not normally been a predominant concern. However, it has been found
that the power consumed during test mode operation is often much higher than during normal mode operation
[1]. This is because most of the consumed power results from the switching activity in the nodes of the circuit
under test (CUT), which is much higher during test mode than during normal mode operation [1]–[3]. In the
proposed pattern, each generated vector applied to each scan chain is an SIC vector, which can minimize the
input transition and reduce test power. In VLSI testing, power reduction is achieved by increasing the correlation
between consecutive test patterns.
Continuation Power Flow Method based Assessment of Static Voltage Stability c...IJERA Editor
Power system security is recognized as one of the major problems in many power systems throughout the world.
Power system insecurity such as transmission lines being overloaded causes transmission elements cascade
outages, which may lead to complete blackout. In accordance with these reasons, the prediction and recognition
of voltage instability in power system has particular importance and it makes the network security stronger. This
work, by considering the power system contingencies based on the effects of them on Mega Watt Margin
(MWM) and maximum loading point (MLP) is focused to analyse the voltage stability using continuation power
flow method. The study has been carried out on IEEE 30-Bus Test System using MATLAB and PSAT
softwares and results are presented.
Low Memory Low Complexity Image Compression Using HSSPIHT EncoderIJERA Editor
Due to the large requirement for memory and the high complexity of computation, JPEG2000 cannot be used in
many conditions especially in the memory constraint equipment. The line-based W avelet transform was
proposed and accepted because lower memory is required without affecting the result of W avelet transform, In
this paper, the improved lifting schem e is introduced to perform W avelet transform to replace Mallat method
that is used in the original line-based wavelet transform. In this a three-adder unit is adopted to realize lifting
scheme. It can perform wavelet transform with less computation and reduce memory than Mallat algorithm. The
corresponding HS_SPIHT coding is designed here so that the proposed algorithm is more suitable for
equipment. W e proposed a highly scale image compression scheme based on the Set Partitioning in
Hierarchical Trees (SPIHT) algorithm. Our algorithm, called Highly Scalable SPIHT (HS_SPIHT), supports
High Compression efficiency, spatial and SNR scalability and provides l bit stream that can be easily adapted to
give bandwidth and resolution requirements by a simple transcoder (parse). The HS_SPIHT algorithm adds
the spatial scalability feature without sacrificing the S NR embeddedness property as found in the original
SPIHT bit stream. Highly scalable image compression scheme based on the SPIHT algorithm the proposed
algorithm used, highly scalable SPIHT (HS_SPIHT) Algorithm, adds the spatial scalability feature to the SPIHT
algorithm through the introduction of multiple resolution dependent lists and a resolution-dependent sorting
pass. SPIHT keeps the import features of the original SPIHT algorithm such as compression efficiency, full
SNR Scalability and low complexity.
By combining the wireless network and E-commerce, suppliers can provide a more convenient and quicker
service on a human scale for their customers. The main advantages of such services are their high availability,
independence of physical location and time. Mobile commerce raises a number of security and privacy
challenges. However, security has always been the key issue for the development of mobile E-commerce, which
is more vulnerable than the traditional E-commerce mode. . In order to solve the problem of security gap in the
transmission of mobile E-commerce information, a framework based on J2ME/MIDP is proposed, which
combines double layer encryption schemes, stego-image and secure XML messages which transferred between
the mobile terminal and the server. Our method provide strong secure and invisible communication with high
security and high operating efficiency that compatible with many types of mobile terminal.
Mitigation of the Harmonics under Reactive Power Compensation by SHPF-TCR Usi...IJERA Editor
In this paper, a combined system of a thyristor-controlled reactor (TCR) and a shunt hybrid power filter
(SHPF)has been designed by MATLAB/SIMULINK approach for harmonic and reactive power compensation.
The quality of the power is effected by many factors like harmonic contamination, due to the increment of nonlinear
loads, sag and swell due to the switching of the loads etc. Also control schemes based on PI and Fuzzy
logic controllers have been proposed to mitigate the harmonics and neutral current . The proposed methodology
not only reduces the complexity but also offers simplicity to implement and increases reliability of the system.
These control strategies also help in achieving a low cost highly effective control. The performance is also
observed under influence of utility side disturbances such as harmonics, flicker and spikes with Non-Linear and
Reactive Loads with different control strategies.
Michaelis-Menten Kinetics in Transient State: Proposal for Reversible Inhibit...IJERA Editor
The enzymatic processes according Michaelis-Menten kinetics have been studied from various approaches to
describe the inhibition state. Proposals for inhibition were compared from a generic process, where kinetic
constants have received unitary values, and the numeric value of the concentration of substrate was ten (10)
times higher than the numerical value of the concentration of enzyme. For each inhibition model proposed,
numerical solutions were obtained from nonlinear system of ordinary differential equations, generating results
presents by graphs showing the variation of the enzyme and enzyme complexes, also the variation of substrate
and product of the reaction. Also, was designed a model with performance, indicating similar behavior to that
seen in the Michaelis-Menten kinetics, where complex of reaction is rapidly formed and throughout the process,
tends to decay to zero. Thus, in this new proposed model, the effect of inhibition starts at zero and, throughout
the process, tends to the nominal value of the initial enzyme concentration. Such responses have proved to be
valid for different values of enzyme concentration and process time, showing robustness. The proposed model
was applied to the hydrolysis of disaccharides, providing a setting with conservation of mass of the model at the
end of the process regarding the responses of the carbohydrate concentration.
Comparative performance analysis of different modulation techniques for papr ...IJCNCJournal
One of the most important multi-carrier tran
smission techniques used in the latest wireless com
munication
arena is known as Orthogonal Frequency Division Mul
tiplexing (OFDM). It has several characteristics
such as providing greater immunity to multipath fad
ing & impulse noise, eliminating Inter Symbol
Interference (ISI) & Inter Carrier Interference (IC
I) using a guard interval known as Cyclic Prefix (C
P). A
regular difficulty of OFDM signal is high peak to a
verage power ratio (PAPR) which is defined as the r
atio
of the peak power to the average power of OFDM Sign
al. An improved design of amplitude clipping &
filtering technique of us previously reduced signif
icant amount of PAPR with slightly increase bit err
or rate
(BER) compare to an existing method in case of Quad
rature Phase Shift Keying (QPSK) & Quadrature
Amplitude Modulation (QAM). This paper investigates
a comparative performance analysis of the differen
t
higher order modulation techniques on that design.
PAPR Reduction in OFDM & MC-CDMA System using Nonlinear Companding TechniquesIDES Editor
High peak to average power ratio (PAPR) of
the transmitted signal is a major drawback of OFDM and
MC-CDMA systems. In this paper various existing nonlinear
companding transforms are analyzed and compared
for the reduction of peak to average power ratio in OFDM
and MC-CDMA systems. Nonlinear companding transforms
transform the amplitude or power of the original signals
into uniform distribution, which can effectively reduce the
PAPR for different modulation formats and subcarrier sizes
without any complexity increase and bandwidth expansion
.Nonlinear companding technique adjust both large and
small signals and can keep the average power at the same
level. Nonlinear companding transforms can significantly
improve the performance of OFDM and MC-CDMA system
including bit-error-rate and PAPR reduction.
Performance comparison of two clipping based filtering methods for papr reduc...ijmnct
The growth of wireless communication technologies has been producing the intense demand for high-speed,
efficient, reliable voice & data communication. As a result, third generation partnership project (3GPP)
has implemented next generation wireless communication technology long term evolution (LTE) which is
designed to increase the capacity and speed of existing mobile telephone & data networks. LTE has
adopted a multicarrier transmission technique known as orthogonal frequency division multiplexing
(OFDM). OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for
very wide carriers. One major generic problem of OFDM technique is high peak to average power ratio
(PAPR) which is defined as the ratio of the peak power to the average power of the OFDM signal. A
trade-off is necessary for reducing PAPR with increasing bit error rate (BER), computational complexity or
data rate loss etc. In this paper, two clipping based filtering methods have been implemented & also
analyzed their modulation effects on reducing PAPR.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
AN OVERVIEW OF PEAK-TO-AVERAGE POWER RATIO REDUCTION TECHNIQUES FOR OFDM SIGNALSijmnct
OFDM (Orthogonal Frequency Division Multiplexing) has been widely adopted for high data rate wireless
communication systems due to its advantages such as extraordinary spectral efficiency, robustness to
channel fading and better QoS (Quality of Service) performance for multiple users. However, some
challenging issues are still unresolved in OFDM systems. One of the issues is the high PAPR (peak-toaverage
power ratio), which results in nonlinearity in power amplifiers, and causes out of band radiation
and in band distortion. This paper reviews some conventional PAPR reduction techniques and their
modifications to achieve better PAPR performance. Advantages and disadvantages of each technique are
discussed in detail. And comparisons between different techniques are also presented. Finally, this paper
makes a prospect forecast about the direction for further researches in the area of PAPR reduction for
OFDM signals
Design Ofdm System And Remove Nonlinear Distortion In OFDM Signal At Transmit...Rupesh Sharma
although OFDM seems to be a solution to keep up with
the demand of increasing data rates, it has some drawbacks.
Sensitivity to high PAPR is the most significant of these
drawbacks. The main objective of this paper was to investigate
and document the effects of PAPR on the performance of OFDM
based digital communications under different channel conditions.
A step-by-step approach was adopted in order to achieve the
objective of this paper. The first step is to provide a basic
background on the principles of OFDM. The reasons for the
PAPR and a theoretical analysis of these effects on OFDM
systems are documented. The OFDM system has a high peak-toaverage
power ratio (PAPR) that can cause unwanted saturation
in the power amplifiers, leading to in-band distortion and out-ofband
radiation. To be able to observe the system behavior, the
simulation results for different channel models are presented in
graphical form. Next, the simulation results obtained in this work
are compared to the simulation results reported in related studies
Peak to Average Power Ratio Reduction in Mc Cdma System by Using Pulse Shapin...IOSR Journals
Abstract: One of the drawback of multicarrier code division multiple access (MC CDMA) is the high peak to
average power ratio (PAPR). In this paper A novel scheme based on pulse shaping described for PAPR
reduction. Here three different pulse shaping filters (Raised cosine, Sinc power pulse and Nyqist pulse) are
described for PAPR reduction in MC CDMA system. The method is based on the proper selection of the pulses
for shaping the different sub carriers of the MC CDMA modulation scheme. It is shown by computer simulation
that the scheme achieves the significant improvement in PAPR reduction in MC CDMA system. Its
implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping
technique can be used not only to shape the spectrum of the transmitted signal but also to reduce its PAPR. In
computer simulation It is observed that by using nyquist pulse near about 6.8 db PAPR is obtained. Which is
considerable PAPR reduction than a PAPR value of Original MC CDMA signal
Keywords: MC CDMA, PAPR, PULSE SHAPING, BPSK
Analysis of Peak to Average Power Ratio Reduction Techniques in Sfbc Ofdm SystemIOSR Journals
Abstract: Orthogonal Frequency Division Multiplexing (OFDM) has become the most popular modulation echnique for high speed data transmission. But the great disadvantage of the OFDM technique is its high Peak to Average Power Ratio (PAPR). In this paper, the Selected Mapping (SLM) technique and Clipping and Differential Scaling is applied to Space Frequency Block Coded (SFBC) OFDM systems to reduce the PAPR with Alamouti coding scheme. In SLM technique, different representations of OFDM symbols are generated by rotation of the original OFDM frame by different phase sequences, and the signal with minimum PAPR is selected and transmitted. To compensate for the effect of the phase rotation at the receiver, it is necessary to transmit the index of the selected phase sequence as side information (SI). Additionally, a suboptimum detection method that does not need SI is introduced at the receiver side. In Clipping and Differential Scaling technique, the amplitude of complex OFDM signal is clipped and then scaled in such a way so that the PAPR is reduced without causing much degradation in bit error rate (BER). The threshold values for clipping and scaling is determined using Monte Carlo Simulations. Simulation results show that the SLM method and Clipping and Scaling method effectively reduce the PAPR. Keywords: Orthogonal frequency division multiplexing (OFDM), peak to average power ratio (PAPR), selected mapping (SLM), space frequency block coded (SFBC), Side information (SI), high power amplifiers (HPA), complementary cumulative density function (CCDF), inter-symbol interference (ISI).
Analysis of Reduction of PAPR by Linear Predictive Coding in OFDM AnuragSingh1049
The major challenge in orthogonal frequency division multiplexing (OFDM) is to reduce high peak to average power ratio (PAPR) that leads to non linear distortion for the application of high power amplifier. PAPR is defined as the ratio between the maximum instantaneous power and its average power. In this paper, we have presented new PAPR reduction technique to reduce peak to average power ratio using Linear predicting coding (LPC) in OFDM system. In this paper, proposed technique show the significant reduction in PAPR without any harmful degradation in power spectral density (PSD), computational complexity (CC) and performance error of the system. This proposed method can be applied for any number of subcarrier and independent of modulation scheme under Additive White Gaussian Noise (AWGN) channel.
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.
Performance Analysis of PAPR Reduction in MIMO-OFDMIJARBEST JOURNAL
Authors: Jayaraman.G1, VeeraKumar K2, Selvakani.S3
Abstract— In communication system, it is aimed to provide highest possible
transmission rate at the lowest possible power and with the least possible noise. MIMOOFDM
has been chosen for high data rate communications and widely deployed in many
wireless communication standards. The major drawback in OFDM signal transmission is
high PAPR. In previous, use clipping technique to tackle this problem. In this paper, use
EM-GAMP algorithm to reduce PAPR in considerable amount.
Performance Analysis of PAPR Reduction in MIMO-OFDM
Gq2411921196
1. Gagandeep Kaur, Rajbir Kaur / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1192-1196
PAPR Reduction of an MC-CDMA System through PTS
Technique using Suboptimal Combination Algorithm
Gagandeep Kaur1, Rajbir Kaur2
1
Student , University College of Engineering, Punjabi University, Patiala, India
Assistant Professor2, University College of Engineering, Punjabi University, Patiala, India
ABSTRACT
Multicarrier Code Division Multiple groups: signal distortion techniques, signal
Access is the most promising technique for high scrambling techniques and coding techniques.
speed data transmission. However, the MC- Signal distortion schemes reduce the amplitude by
CDMA signals are characterized by large peak to linearly distorting the MC-CDMA signal at or
average power ratios (PAPR), which can reduce around the peaks. This includes techniques like
the system efficiency. In this paper PAPR clipping, peak windowing, and peak cancellation
reduction of an MC-CDMA system using PTS [1], [5]. It is the simplest technique but it causes in-
technique is investigated by using suboptimal band and out-band distortion. Scrambling scheme is
combination algorithm, which uses binary phase based on scrambling each MC-CDMA signal with
factors, for BPSK and QPSK modulation large PAPR. It includes techniques such as Selected
techniques at different number of active users. Mapping (SLM), and Partial Transmit Sequence
The results show that BPSK is a more effective (PTS). In case of PTS technique [7-8], MC-CDMA
modulation scheme for PAPR reduction in MC- sequences are partitioned into sub-blocks and each
CDMA system. sub-block is multiplied by phase weighting factor to
produce alternative sequences with low PAPR.
Keywords: MC-CDMA, PAPR, Partial Transmit However large number of phase weighting factors
Sequence, Complementary Cumulative Distribution increases the hardware complexity and makes the
Function. whole system vulnerable to the effect of phase
noise. The SLM technique [9-16] pseudorandomly
1. INTRODUCTION modifies the phases of the original information
The multicarrier transmission has been symbols in each MC-CDMA block several times
considered as an attractive technique that offers the and selects the phase modulated MC-CDMA with
desired high data rates for the 4G mobile best PAPR performance for transmission.
environment. It also has advantages for spectral In this paper we have investigated PAPR
efficiency and low cost implementation. reduction on partial transmit sequence (PTS)
Multicarrier code division multiple access technique method using suboptimal combination algorithm
(MC-CDMA) is a combination of CDMA scheme which uses binary phase factors.
and OFDM signaling is the most promising
candidate for the next generation of wireless 2. SYSTEM DESCRIPTION
communication for achieving high data rates. In 2.1 MC-CDMA system
addition it provides an efficient method for The transmitter model of downlink MC-
frequency diversity, overcoming the inter-symbol CDMA system is shown in fig.1. The block of M
interference (ISI) in frequency selective Rayleigh complex valued symbol, d ( k ) [d1( k ) , d2k ) ,..., d M ) ] of
( (k
fading environment by using guard interval. [1]- [3] th
the k user is firstly serial –paralleled into a M-
However, MC-CDMA has some major length vector as d [d1 , d 2 ,..., d M ] ,
(k ) (k ) (k ) (k ) T
drawbacks to implement it in practical
k=1,2,…,K. After this serial to parallel conversion,
telecommunication systems. One of them is that
each symbol is frequency domain spread by a user
MC-CDMA signal suffers a high Peak to Average
Power Ratio (PAPR). A high PAPR easily makes spreading code c( k ) [c1( k ) , c2k ) ,..., cLk ) ] , where L
( (
signal peaks to move into the non-linear region of denotes length of the spreading code. As spreading
the RF power amplifier which causes signal sequences, orthogonal sets of sequences are
distortion. A large PAPR increases the complexity preferred for reducing low multiuser interference.
of the analog-to-digital and digital-to-analog Walsh-Hadamard (WH) sequences are used as
converters and reduces the efficiency of RF power spreading sequences in this procedure. The input of
amplifier. K users is summed up and is interleaved in
Therefore it is desirable that transmitted frequency domain as
K
signal possess reduced peaks and in order to achieve
this there are several PAPR reduction techniques. X X
k 1
(k )
[X 0 , X1 ,..., X N 1 ]T to obtain the
These techniques are divided into three
diversity effects by placing the chip symbol
elements that corresponds to same symbol on
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Vol. 2, Issue4, July-August 2012, pp.1192-1196
subcarrier that are distance M apart. After frequency The CCDF of the PAPR of the data block
interleaving the symbol elements are fed into IFFT is desired is our case to compare various reduction
block of size N M L for OFDM operation. The techniques. This is given by [4]:
resultant baseband signal for one MC-CDMA
symbol is represented as P( PAPR ) 1 P( PAPR )
1 F ( ) N
K M L
dmk ) cl(k ) e j 2 (M (l 1)(m1))t / NT
1
s(t ) (
(1) 1 (1 exp( )) N (4)
N k 1 m 1 l 1
When calculating the PAPR, we have to
consider the actual time domain signal that is in
analog form. The IFFT outputs, which are symbol
spaced sampling values, will miss some of the signal
peaks. Therefore, if we calculate PAPR by using
these sample values, then the calculated PAPR is
less than the actual PAPR [9]. This is an optimistic
result and will not illustrate the real situation.
However, they are enough for signal reconstruction.
To account for this issue, oversampling is performed
by low pass filtering the IFFT signal and then
sampled at higher rate. Now, the increased samples
Figure 1: MC-CDMA transmitter are close to the real analog signal and calculation of
PAPR based on these sample will give a better
2.2 PAPR and Cumulative Distribution Function
estimated PAPR.
Although MC-CDMA is a powerful
multiple access technique but it is not problem free.
MC-CDMA signal has large peak to average ratio 3. PARTIAL TRANSMIT SEQUENCE
(PAPR) .MC-CDMA consist of large number of (PTS) METHOD
independently modulated sub carriers where N This method is based on phase shifting of
modulated subcarriers are added with same phase, sub-blocks of data and multiplication of data
then peak power is N times the power of MC- structure by random vectors. The main purpose
CDMA signal.High PAPR values cause a serious behind this method is that the input data frame is
problem to linear power amplifier (PA) used at divided into non-overlapping sub-blocks and each
transmitter. sub-blocks is phase shifted by constant factor to
The PAPR of the MC-CDMA symbol is reduce PAPR [9]. In the PTS technique, an input
defined as ratio of the peak power and the average data block of N symbols is partitioned into disjoint
power of a multicarrier signal: sub-bocks. The subcarriers in each sub-block are
weighted by phase factor for that sub-block. The
max s (t )
2 phase factors are selected such that the PAPR of the
p peak
combined signal is minimized. There are three
PAPR 10 log10 different kinds of sub-block partitioning schemes on
E s (t )
paverage 2
which the performance of PTS technique depends:
adjacent, interleaved, and pseudorandom. [10-12]
(2)
where ppeak represents output peak power, paverage
means output average power. denotes the
expected value.
The cumulative distribution function
(CDF) is one of the most regularly used parameters,
which is used to measure the efficiency on any
PAPR technique. Normally, the Complementary
CDF (CCDF) is used instead of CDF, which helps
us to measure the probability that the PAPR of a Figure 2: Block diagram of conventional PTS
certain data block exceeds the given threshold [5]. scheme
The CDF of the amplitude of a sample signal is In the conventional PTS scheme in MC-
given by CDMA, before applied to IFFT operation, X, i.e.,
the sum of all active user sequences after spreading
F ( ) 1 exp( ) (3) and frequency interleaving is input to PTS model as
shown in figure 2. [12]
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Vol. 2, Issue4, July-August 2012, pp.1192-1196
The data block, Xn , n=0,1,…,N-1 is defined as 4. SIMULATIONS
vector, X [ X 0, X 1,...., XN 1]T . Then partition X into In this section the performance MC-CDMA
V disjoint sets, represented by vectors X(v) , system is evaluated using SLM. Table I above
v=1,2,…,V such that shows the simulation parameters. If we oversample
V a transmitted signal by a factor of four, the discrete
X X
v 1
(v)
(5) PAPR is almost the same as continuous PAPR [13].
Thus we oversample the transmitted signal by a
The objective of PTS approach is to form factor of four in IFFT process.
weighted combination of V clusters, each of equal
size. TABLE I
V
SIMULATION PARAMETERS
S b
v 1
(v )
X (V ) (6) Spreading codes Walsh
where b(v) , v=1,2,…,V are weighting factors or Hadamard
phase factors and are assumed to be pure rotations. Modulation process BPSK, QPSK
After transferring in time domain equation (6) Processing Gain (L) 16
becomes Number of data symbols per an 8
V MC-CDMA symbol (M)
s(t ) b( v ) x (V ) (7) Number of sub-carriers (N) 128
v 1 Number of active users (K) 8,16
The vector x(v) called partial transmit sequence is Number of phase sequences (U) 4,8 and 16
the IFFT of X(V). The weighting factors are chosen to Oversampling factor 4
minimize the PAPR by searching for the appropriate
combination of each cluster and by corresponding The performance metric utilized in
weighting clusters. evaluating PAPR reduction scheme is CCDF of the
b (1) , b (2) ,..., b (V ) b (1),b (2),...,b (V ) 0max1 b(v) xn(v)
V
PAPR of transmitted continuous time signal. The
arg min
m N
v 1 resulting CCDF curves are presented for 1,000 input
symbol sequences for different number of phase
sequences (V=2, 4, 8) when considered number of
(8)
active users to be equal to 8and 16. The phase
The combination with weighting factors is called
sequences used are binary phase sequences {1,-1},
rotation factor or combining sequence. Optimized
which are constructed by suboptimal combination
transmit sequence is
V
algorithm. The system consists of 128 subcarriers
s (t ) b ( v ) xmv )
( (9) with modulation schemes used to be BPSK and
v 1 QPSK. The results are compared with the original
In suboptimal combination algorithm, we MC-CDMA signal.
consider binary (i.e., 1) weighting factors. After
dividing the input data block into V clusters, form
the VN-point PTS’s. As first step, assume that bv 1
for all v and compute the PAPR for the combined
signal (7). Next, invert the first has factor b1 1
and recomputed the resulting PAPR. If the new
PAPR is lower than the previous step, retain b1 as a
part of final phase sequence; otherwise, b1 reverts to
its previous value. The algorithm continues in this
fashion until all V possibilities for “flipping” the
signs have been explored.
This algorithm can be summarized as :
1. Partion the input data block into V subsets as in
equation (5).
2. Set all the phase factors bv for v=1:V, find
PAPR of equation (7), and set it as PAPR_min.
3. Set the v=2. Figure 3: CCDF of PAPR of BPSK modulated MC-
4. Find PAPR of equation (7) with bv = -1. CDMA using PTS scheme for various values of V
5. If PAPR>PAPR_min, switch bv back to 1. with K =8
Otherwise, update PAPR_min=PAPR.
6. If v<V, increment v by 1 and go back to step 4. Fig. 3 shows the CCDF curves of an BPSK
Otherwise, exit this process with the set of modulated MC-CDMA system with PTS technique
for 8 users (K=8). In figure 3, at CCDF=10-3, the
optimal phase factors, b . PAPR is reduced by 1dB, 2dB, 4.2dB for values of
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4. Gagandeep Kaur, Rajbir Kaur / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1192-1196
V=4,8 and 16 respectively when compared with the
original MC-CDMA signal.
Figure 6: CCDF of PAPR of QPSK modulated MC-
CDMA using PTS scheme for various values of V
with K =16
Figure 4: CCDF of PAPR of QPSK modulated MC-
Fig. 6 shows the CCDF curves of a QPSK
CDMA using PTS scheme for various values of V
modulated MC-CDMA system with PTS technique
with K=8
for 16 users (K=16). In figure 6, at CCDF=10-3, the
PAPR is reduced by 1dB, 1.4dB, 1.9dB for values of
Fig. 4 shows the CCDF curves of a QPSK
V=4,8 and 16 respectively when compared with the
modulated MC-CDMA system with PTS technique
original MC-CDMA signal.
for 8 users (K=8). In figure 4, at CCDF=10-3, the
PAPR is reduced by 0.3dB, 1.4dB, 4.3dB for values
of V=4,8 and 16 respectively when compared with 5. CONCLUSION
the original MC-CDMA signal. In this paper we examined the effect of
PTS to reduce PAPR of MC-CDMA for different
modulation schemes. The binary phase sequences
considered in this paper are generated with the help
of suboptimal combination algorithm. From the
computer simulation, the results obviously shows
that PAPR reduction performance depends upon
various number of phase sequence factors (V) and it
significantly improves with increase in number of V
for any number of active users and the modulation
technique. PAPR performance is also compared for
different modulation schemes (QPSK and BPSK)
and simultaneously for different number of users.
The results show that higher PAPR reduction
performance is achieved when BPSK is used as a
modulation technique than QPSK for same number
of active users. The results showed that PTS is more
effective when BPSK is used as modulation scheme.
Figure 5: CCDF of PAPR of BPSK modulated MC- From the graphs it can also be concluded that PAPR
CDMA using PTS scheme for various values of V reduction performance increases with increase in
with K =16 number of active users.
Fig. 5 shows the CCDF curves of a BPSK ACKNOWLEDGMENT
modulated MC-CDMA system with PTS technique We are grateful to the University College
for 16 users (K=16). In figure 5, at CCDF=10-3, the of Engineering, Punjabi University, Patiala for
PAPR is reduced by 1.2dB, 2.1dB, 2.5dB for values providing necessary support and infrastructure
of V=4,8 and 16 respectively when compared with
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Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1192-1196
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