Orthogonal frequency division multiplexing (OFDM) has become an important component of waveform
generation in wideband transmission. it's a superior technology for the high-speed rate of wired and
wireless communication systems. Currently, multiple-input multiple-output orthogonal frequency division
multiplexing (MIMO OFDM) systems are crucial wireless communication systems like 4G and 5G
networks & tactical communication. The OFDM has many advantages over other techniques like its high
capacity and immunity against multipath fading channels. However, one amongst the foremost drawbacks
of the OFDM system is that the high-peak-to-average power ratio (PAPR) that leads the system to provide
in-band distortion and out-of-band radiation and reduces its efficiency. This problem increases with a rise
within the number of transmit antennas. Therefore, it's highly desirable to cut back the PAPR of an OFDM
signal. For this, numerous techniques are proposed to beat the PAPR problem like i) Selective mapping
(SLM) ii) Partial transmit sequence (PTS), iii) Clipping, iv) Clipping and filtering. All of those are reduced
the PAPR by generating alternative subcarrier vector that are statistically independent OFDM symbols for
a given data frame and transmitting the symbol with rock bottom peak power. During this paper we also
proposed, some hybrid techniques. The hybrid techniques are the technique of clipping is employed in
conjunction with SLM and PTS to cut back computational complexity. And also the combination of SLM-
PTS to scale back PAPR. Simulations are acquainted with analyze the efficiency of the techniques used
which signifies OFDM to be providing much better PAPR reduction and a way better Bit Error Rate
(BER). it's shown in simulation results that the proposed scheme performs well reducing PAPR. But the
proposed scheme is more complex than the prevailing techniques.
PAPR REDUCTION TECHNIQUES AND THEIR BIT ERROR RATE MEASUREMENT AT OFDM IN LTE...pijans
Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform generation in wideband digital communication since its first appearance in digital audio broadcasting (DAB)and it is indeed in use. These descriptions are simplified version of the detailed descriptions provided by 3gpp. It is a superior technology for the high-speed data rate of wire-line and wireless communication systems. The OFDM has many advantages over other techniques such as its high capacity and immunity against multipath fading channels. However ,one of the main drawbacks of the OFDM system is the high-peak-to-average power ratio (PAPR) that leads the system to produce in-band distortion and out-of-band radiation because of the non-linearity and reduces its efficiency is the distortion of the signal caused at the High Power Amplifier (HPA) of a transmitter . Therefore, it is highly desirable to reduce the PAPR of an OFDM signal. For this, numerous techniques have been proposed to overcome the PAPR problem such as i) selective mapping(SLM) ii) partial transmit sequence (PTS), iii) clipping, iv) clipping and filtering. In this paper, the PTS technique was analytically reviewed as one of the important methods to reduce the high PAPR problem. Simulations are used to analyze the efficiency of the techniques used which signifies OFDM to be providing much better PAPR reduction and a better Bit Error Rate (BER) . From simulation results clipping method shows good PAPR reduction with significant amount of BER degradation. Clipping and filtering method shows slight increase in PAPR with small degradation in BER performance than Clipping method and both methods are computationally less complex. PTS provides good PAPR reduction with high computational complexity.
PAPR REDUCTION TECHNIQUES AND THEIR BIT ERROR RATE MEASUREMENT AT OFDM IN LTE...pijans
Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform
generation in wideband digital communication since its first appearance in digital audio broadcasting
(DAB)and it is indeed in use. These descriptions are simplified version of the detailed descriptions
provided by 3gpp. It is a superior technology for the high-speed data rate of wire-line and wireless
communication systems. The OFDM has many advantages over other techniques such as its high capacity
and immunity against multipath fading channels. However ,one of the main drawbacks of the OFDM
system is the high-peak-to-average power ratio (PAPR) that leads the system to produce in-band distortion
and out-of-band radiation because of the non-linearity and reduces its efficiency is the distortion of the
signal caused at the High Power Amplifier (HPA) of a transmitter . Therefore, it is highly desirable to
reduce the PAPR of an OFDM signal. For this, numerous techniques have been proposed to overcome the
PAPR problem such as i) selective mapping(SLM) ii) partial transmit sequence (PTS), iii) clipping, iv)
clipping and filtering. In this paper, the PTS technique was analytically reviewed as one of the important
methods to reduce the high PAPR problem. Simulations are used to analyze the efficiency of the techniques
used which signifies OFDM to be providing much better PAPR reduction and a better Bit Error Rate
(BER) . From simulation results clipping method shows good PAPR reduction with significant amount of
BER degradation. Clipping and filtering method shows slight increase in PAPR with small degradation in
BER performance than Clipping method and both methods are computationally less complex. PTS provides
good PAPR reduction with high computational complexity.
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.
A modified design of acf operation for reducing papr of ofdm signalijngnjournal
Next generation wireless communication technology long term evolution (LTE) has implemented
orthogonal frequency division multiplexing (OFDM) technique as a strong candidate for radio access
systems. It has several attributes such as providing robustness to multipath fading & impulse noise,
eliminating intersymbol interference (ISI), inter carrier interference (ICI) & the need for equalizers. The
major challenging issue of OFDM technique is the 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, a moderately modified design of amplitude clipping & filtering operation (ACF) is
proposed and implemented which shows the significant improvement in case of PAPR reduction for both
quadrature phase shift keying (QPSK) & quadrature amplitude modulation (QAM) while increasing slight
BER match up to to an existing method.
A Modified Design Of Acf Operation For Reducing Papr Of Ofdm Signaljosephjonse
Next generation wireless communication technology long term evolution (LTE) has implemented orthogonal frequency division multiplexing (OFDM) technique as a strong candidate for radio access systems. It has several attributes such as providing robustness to multipath fading & impulse noise, eliminating intersymbol interference (ISI), inter carrier interference (ICI) & the need for equalizers. The major challenging issue of OFDM technique is the 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, a moderately modified design of amplitude clipping & filtering operation (ACF) is proposed and implemented which shows the significant improvement in case of PAPR reduction for both quadrature phase shift keying (QPSK) & quadrature amplitude modulation (QAM) while increasing slight BER match up to to an existing method.
Peak to Average Ratio PAPR Reduction Technique in OFDM MIMO System A Reviewijtsrd
Orthogonal Frequency Division Multiplexing OFDM is an new method for fourth generation wireless communication. MIMO OFDM has become a promising candidate for high performance 4G and 5G broadband wireless communications. However, one main of MIMO OFDM is the high peak to average power ratio PAPR of the transmitter’s output signal on different antennas. In this paper, we present a new noble SLM PAPR reduction techniques such as selective mapping technique and Partial transmit sequence techniques and shows which of these PAPR reduction techniques are more effective to reduce PAPR in OFDM MIMO. Er. Sukhjinder Singh | Dr. Hitanshu Kumar | Dr. Arashdeep Singh "Peak to Average Ratio (PAPR) Reduction Technique in OFDM-MIMO System- A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-3 , April 2022, URL: https://www.ijtsrd.com/papers/ijtsrd49719.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/49719/peak-to-average-ratio-papr-reduction-technique-in-ofdmmimo-system-a-review/er-sukhjinder-singh
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
PAPR REDUCTION TECHNIQUES AND THEIR BIT ERROR RATE MEASUREMENT AT OFDM IN LTE...pijans
Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform generation in wideband digital communication since its first appearance in digital audio broadcasting (DAB)and it is indeed in use. These descriptions are simplified version of the detailed descriptions provided by 3gpp. It is a superior technology for the high-speed data rate of wire-line and wireless communication systems. The OFDM has many advantages over other techniques such as its high capacity and immunity against multipath fading channels. However ,one of the main drawbacks of the OFDM system is the high-peak-to-average power ratio (PAPR) that leads the system to produce in-band distortion and out-of-band radiation because of the non-linearity and reduces its efficiency is the distortion of the signal caused at the High Power Amplifier (HPA) of a transmitter . Therefore, it is highly desirable to reduce the PAPR of an OFDM signal. For this, numerous techniques have been proposed to overcome the PAPR problem such as i) selective mapping(SLM) ii) partial transmit sequence (PTS), iii) clipping, iv) clipping and filtering. In this paper, the PTS technique was analytically reviewed as one of the important methods to reduce the high PAPR problem. Simulations are used to analyze the efficiency of the techniques used which signifies OFDM to be providing much better PAPR reduction and a better Bit Error Rate (BER) . From simulation results clipping method shows good PAPR reduction with significant amount of BER degradation. Clipping and filtering method shows slight increase in PAPR with small degradation in BER performance than Clipping method and both methods are computationally less complex. PTS provides good PAPR reduction with high computational complexity.
PAPR REDUCTION TECHNIQUES AND THEIR BIT ERROR RATE MEASUREMENT AT OFDM IN LTE...pijans
Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform
generation in wideband digital communication since its first appearance in digital audio broadcasting
(DAB)and it is indeed in use. These descriptions are simplified version of the detailed descriptions
provided by 3gpp. It is a superior technology for the high-speed data rate of wire-line and wireless
communication systems. The OFDM has many advantages over other techniques such as its high capacity
and immunity against multipath fading channels. However ,one of the main drawbacks of the OFDM
system is the high-peak-to-average power ratio (PAPR) that leads the system to produce in-band distortion
and out-of-band radiation because of the non-linearity and reduces its efficiency is the distortion of the
signal caused at the High Power Amplifier (HPA) of a transmitter . Therefore, it is highly desirable to
reduce the PAPR of an OFDM signal. For this, numerous techniques have been proposed to overcome the
PAPR problem such as i) selective mapping(SLM) ii) partial transmit sequence (PTS), iii) clipping, iv)
clipping and filtering. In this paper, the PTS technique was analytically reviewed as one of the important
methods to reduce the high PAPR problem. Simulations are used to analyze the efficiency of the techniques
used which signifies OFDM to be providing much better PAPR reduction and a better Bit Error Rate
(BER) . From simulation results clipping method shows good PAPR reduction with significant amount of
BER degradation. Clipping and filtering method shows slight increase in PAPR with small degradation in
BER performance than Clipping method and both methods are computationally less complex. PTS provides
good PAPR reduction with high computational complexity.
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.
A modified design of acf operation for reducing papr of ofdm signalijngnjournal
Next generation wireless communication technology long term evolution (LTE) has implemented
orthogonal frequency division multiplexing (OFDM) technique as a strong candidate for radio access
systems. It has several attributes such as providing robustness to multipath fading & impulse noise,
eliminating intersymbol interference (ISI), inter carrier interference (ICI) & the need for equalizers. The
major challenging issue of OFDM technique is the 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, a moderately modified design of amplitude clipping & filtering operation (ACF) is
proposed and implemented which shows the significant improvement in case of PAPR reduction for both
quadrature phase shift keying (QPSK) & quadrature amplitude modulation (QAM) while increasing slight
BER match up to to an existing method.
A Modified Design Of Acf Operation For Reducing Papr Of Ofdm Signaljosephjonse
Next generation wireless communication technology long term evolution (LTE) has implemented orthogonal frequency division multiplexing (OFDM) technique as a strong candidate for radio access systems. It has several attributes such as providing robustness to multipath fading & impulse noise, eliminating intersymbol interference (ISI), inter carrier interference (ICI) & the need for equalizers. The major challenging issue of OFDM technique is the 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, a moderately modified design of amplitude clipping & filtering operation (ACF) is proposed and implemented which shows the significant improvement in case of PAPR reduction for both quadrature phase shift keying (QPSK) & quadrature amplitude modulation (QAM) while increasing slight BER match up to to an existing method.
Peak to Average Ratio PAPR Reduction Technique in OFDM MIMO System A Reviewijtsrd
Orthogonal Frequency Division Multiplexing OFDM is an new method for fourth generation wireless communication. MIMO OFDM has become a promising candidate for high performance 4G and 5G broadband wireless communications. However, one main of MIMO OFDM is the high peak to average power ratio PAPR of the transmitter’s output signal on different antennas. In this paper, we present a new noble SLM PAPR reduction techniques such as selective mapping technique and Partial transmit sequence techniques and shows which of these PAPR reduction techniques are more effective to reduce PAPR in OFDM MIMO. Er. Sukhjinder Singh | Dr. Hitanshu Kumar | Dr. Arashdeep Singh "Peak to Average Ratio (PAPR) Reduction Technique in OFDM-MIMO System- A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-3 , April 2022, URL: https://www.ijtsrd.com/papers/ijtsrd49719.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/49719/peak-to-average-ratio-papr-reduction-technique-in-ofdmmimo-system-a-review/er-sukhjinder-singh
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
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.
Performance Analsis of Clipping Technique for Papr Reduction of MB-OFDM UWB S...ijcisjournal
Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) is used as efficacious procedure for
ultra-wideband (UWB) wireless communication applications, which divides the spectrum into various subbands,
whose bandwidth is approximately 500MHz. Major arduousness in multiband-OFDM is ,it have
very large peak to average power ratio value which causes the signal to enter into dynamic region that
consequence in the loss of orthogonal properties and results in the interference of the carrier signals which
crops the amplifier saturation and finally limits the capacity of the system. Many PAPR amortize
algorithms have reported in the survey and pre-coding is PAPR reduction which is inserted after
modulation in the OFDM system. The Existing work presents the reduction of that value by different
clipping techniques namely Classical-Clipping (CC), Heavy side-Clipping (HC), Deep-Clipping (DC) and
Smooth-Clipping (SC) and their comparison analysis is done. Every clipping method is best at its own
level .The proficiency of these strategies are evaluated in locutions of average power disparity, complete
system decadence and PAPR reduction. Finally results show the MB OFDM yields better performance to
reduce PAPR in effective way.
PAPR Reduction in OFDM using Active and Non-Active ChannelsIOSR Journals
Abstract : According to the request of advance communication field there should be high data rate in addition to both power efficiency and lower bit error rate. This request of high data rate can be achieved by the multi carrier modulation scheme using the OFDM technique. But the great drawback of the OFDM technique is its high peak to average power ratio (PAPR). High PAPR reduces OFDM signals by driving the analog amplifier to work in the nonlinear region, changing this way the signal and making the amplifier to consume more power. To reduce the PAPR methods exist which adjust or present new signals to battle large signal peaks. The methods which use data carrying channels are called active channel methods and which use redundant channel are called non active channel methods. This work deals with reduction of the PAPR of OFDM signal using both Active and Non Active Channels. Clipping technique has been applied to active channels and Tone reservation has been applied to Non Active Channels. By using both channels we can get considerable reduction in PAPR. Keywords:Orthogonal Frequency Division Multiplexing (OFDM), Peak to Average Power Ratio (PAPR), Power Amplifier (PA).
Blind Channel Shortening for MIMO-OFDM System Using Zero Padding and Eigen De...ijsrd.com
This paper deals with multiple-input multiple-output (MIMO) broadband wireless communication systems, employing orthogonal frequency-division multiplexing (OFDM). In order to exploit the benefits of OFDM in highly frequency-selective channels, without any significant increase in receiver complexity, a channel shortening prefilter is inserted at the receiver. The main aim of inserting channel shorteners is to shorten the channel so that the main energy of the composite channel is concentrated within a duration smaller than the guard interval inserted while transmission. Thus by including channel shortening equalizers at the receiver the inter symbol interference or the inter block interference can be suppressed. The new approach proposed in this thesis is zero padding approach with Eigen decomposition approach. The advantages of the proposed approaches include immunity to delay spread, resistance to frequency selective fading and simple equalization. This shortening design is a blind one, i.e., a priori knowledge of the MIMO channel impulse response to be shortened is not required, and can be carried out in closed-form.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
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.
Channel Coding and Clipping in OFDM for WiMAX using SDRidescitation
Recent developments in broadband wireless
technology heightened the need for WiMAX which assures
high-speed data services. Mobile WiMAX is grounded on
orthogonal frequency division multiplexing/orthogonal
frequency division multiplexing Access (OFDM/OFDMA)
technology which is an increasing important technique in
LTE systems. This paper describes the OFDM transceiver
implementation using software-defined radio system (SDR).
A SDR is a radio communication system where elements have
been generally implemented in hardware are rather
implemented by software on a personal computer. In this paper,
the software part is realized using GNU Radio and the
hardware part is implemented using USRP N210. OFDM poses
a problem of a Peak to Average Power Ratio (PAPR) or high
crest factor. To stave off this problem either High Power
Amplifiers (HPAs) with large dynamic range or PAPR reduction
techniques are used. The former scheme raises cost of the
system, while the latter induces redundancy or distortion.
This paper presents a novel architecture (which combines
channel coding and clipping) for the PAPR reduction and
analyzes various parameters which effects the performance
of OFDM such as power spectral density, the crest factor and
BER. Channel coding part is framed of three steps
randomization, Forward Error Correction (FEC) and
interleaving. In clipping, certain threshold limits the
amplitude of time domain samples. Without filtering, clipping
causes out-of-band radiation. The paper analyzes the out band
radiation value (at 2.395 GHz) and PAPR reduction with respect
to clipping threshold value. This scheme is preferred because
of its lower complexity and hence would be cheaper to
implement than conventional reduction techniques.
Experimental results prove that the clipping method reduced
PAPR significantly as the number of clip and filtering level is
increased.
A Review Paper on: The PAPR Analysis of MIMO-OFDM SystemsIJEEE
Orthogonal frequency division Multiplexing (OFDM) is one of the most popular multicarrier or multiplexing modulation techniques which transmits many signals over a single path in high speed wireless communication. OFDM convert high data rate stream in to smaller data rate stream. Due to this high data rate and ability to combat frequency selective fading, OFDM has a strong candidate for 4G wireless networks. Because of OFDM-MIMO advantages in multipath fading channel e.g. stout against ISI, ICI and some other advantages like best QoS for multiple users, efficient convention of bandwidth it is suggested to be the modulation technique for next generation 4G networks e.g. LTE. OFDM combined with multiple-input multiple-output (MIMO) to increase system capacity over the time variant frequency-selective channels and the diversity gain. The radio transmitter stations for covering and getting enough transmitted power in their desired area has to use High Power Amplifier (HPA) operable near to the saturation region or else, an aspect memory-less nonlinear distortion will affect the communication path. But along with all its advantages there are some disadvantages also. e.g. High PAPR (Peak to Average Power Ratio) at the transmitter end and BER (Bit Error Rate) at the receiving end. As OFDM is only used in the downlink of 4G networks. To reduce the problems of OFDM-MIMO systems some procedures as SLM, PTS, Clipping, Coding, & Pre-coding etc are suggested but none of them is proficient enough to reduce the PAPR and BER up to standard value. This Paper will discuss some techniques of PAPR reduction, and both their advantages and disadvantages.
A review paper on the papr analysis of orthogonal frequency division multiple...ijmnct
OFDM (Orthogonal Frequency Division Multiplexing) has been raised a new modulation technique. Due
to its advantages in multipath fading channel e.g. robust against ISI, ICI and some other advantages like
best QoS for multiple users, efficient usage of bandwidth it is suggested to be the modulation technique for
next generation 4G networks e.g. LTE. But along with all its advantages there are some disadvantages also
e.g. High PAPR (Peak to Average Power Ratio) at the transmitter end and BER (Bit Error Rate) at the
receiving end. Since OFDM is only used in the downlink of 4G networks. To reduce the problems of OFDM
some techniques e.g. SLM, PTS, Clipping, Coding, & Pre-coding etc are suggested but none of them is
reduce the PAPR and BER to an acceptable value. This Paper will discuss some techniques of PAPR &
BER reduction, and their advantages and disadvantages in detail.
DYNAMIC OPTIMIZATION OF OVERLAPAND- ADD LENGTH OVER MBOFDM SYSTEM BASED ON SN...cscpconf
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
An Optimized Mechanism for Adaptive and Dynamic Policy Based Handover in Clus...pijans
On-going revolution in ever-improving wireless communication enforces the necessity of a self configuring,
rapidly deployable and infrastructure less network. MANET is such an autonomous wireless network that
meets the requirements. At the same time MANET’s random behavior and absence of any central
intelligence to gather unambiguous knowledge about user contexts complexes QoS maintenance and
hampers proper utilization of network resources resulting into unnecessary handovers. In past, few policy
driven handover approaches have been proposed for MANET but none of them explores a comprehensive
policy design. Therefore in this paper we propose an adaptive and optimized policy based handover
mechanism which is based on explicitly designed policies like load balancing, service discovery and next
hop selection .Efficient procedures for these policies are also explored .This work predicts the high time of
handover need on the basis of application specific needs of individual freely roaming mobile nodes,
avoiding unnecessary handovers and provides efficient handover procedure with optimized resource
consumption, reduced latency and interruption time.
An Efficient Routing Protocol for Mobile Ad Hoc Network for Secured Communica...pijans
Security and reliable communication is challenging task in mobile Ad Hoc network. Through mobility of network device compromised with attack and loss of data. For the prevention of attack and reliable communication, various authors proposed a method of secured routing protocol such as SAODV and SBRP (secured backup routing protocol). The process of these methods work along with route discovery and route maintains, discovery and route maintained needed more power consumption for that process. The power of devices is decrease during such process and network lifetimes expire. In this paper, we modified the secured stateless protocol for secured routing and minimized the utilization of power during path discovering and establishment. For the authentication of group node used group signature technique and sleep mode threshold concept for power minimization. Our proposed technique is simulated in ns-2 and compare to other routing protocol gives a better performance in comparison to energy consumption and throughput of network.
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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.
Performance Analsis of Clipping Technique for Papr Reduction of MB-OFDM UWB S...ijcisjournal
Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) is used as efficacious procedure for
ultra-wideband (UWB) wireless communication applications, which divides the spectrum into various subbands,
whose bandwidth is approximately 500MHz. Major arduousness in multiband-OFDM is ,it have
very large peak to average power ratio value which causes the signal to enter into dynamic region that
consequence in the loss of orthogonal properties and results in the interference of the carrier signals which
crops the amplifier saturation and finally limits the capacity of the system. Many PAPR amortize
algorithms have reported in the survey and pre-coding is PAPR reduction which is inserted after
modulation in the OFDM system. The Existing work presents the reduction of that value by different
clipping techniques namely Classical-Clipping (CC), Heavy side-Clipping (HC), Deep-Clipping (DC) and
Smooth-Clipping (SC) and their comparison analysis is done. Every clipping method is best at its own
level .The proficiency of these strategies are evaluated in locutions of average power disparity, complete
system decadence and PAPR reduction. Finally results show the MB OFDM yields better performance to
reduce PAPR in effective way.
PAPR Reduction in OFDM using Active and Non-Active ChannelsIOSR Journals
Abstract : According to the request of advance communication field there should be high data rate in addition to both power efficiency and lower bit error rate. This request of high data rate can be achieved by the multi carrier modulation scheme using the OFDM technique. But the great drawback of the OFDM technique is its high peak to average power ratio (PAPR). High PAPR reduces OFDM signals by driving the analog amplifier to work in the nonlinear region, changing this way the signal and making the amplifier to consume more power. To reduce the PAPR methods exist which adjust or present new signals to battle large signal peaks. The methods which use data carrying channels are called active channel methods and which use redundant channel are called non active channel methods. This work deals with reduction of the PAPR of OFDM signal using both Active and Non Active Channels. Clipping technique has been applied to active channels and Tone reservation has been applied to Non Active Channels. By using both channels we can get considerable reduction in PAPR. Keywords:Orthogonal Frequency Division Multiplexing (OFDM), Peak to Average Power Ratio (PAPR), Power Amplifier (PA).
Blind Channel Shortening for MIMO-OFDM System Using Zero Padding and Eigen De...ijsrd.com
This paper deals with multiple-input multiple-output (MIMO) broadband wireless communication systems, employing orthogonal frequency-division multiplexing (OFDM). In order to exploit the benefits of OFDM in highly frequency-selective channels, without any significant increase in receiver complexity, a channel shortening prefilter is inserted at the receiver. The main aim of inserting channel shorteners is to shorten the channel so that the main energy of the composite channel is concentrated within a duration smaller than the guard interval inserted while transmission. Thus by including channel shortening equalizers at the receiver the inter symbol interference or the inter block interference can be suppressed. The new approach proposed in this thesis is zero padding approach with Eigen decomposition approach. The advantages of the proposed approaches include immunity to delay spread, resistance to frequency selective fading and simple equalization. This shortening design is a blind one, i.e., a priori knowledge of the MIMO channel impulse response to be shortened is not required, and can be carried out in closed-form.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
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.
Channel Coding and Clipping in OFDM for WiMAX using SDRidescitation
Recent developments in broadband wireless
technology heightened the need for WiMAX which assures
high-speed data services. Mobile WiMAX is grounded on
orthogonal frequency division multiplexing/orthogonal
frequency division multiplexing Access (OFDM/OFDMA)
technology which is an increasing important technique in
LTE systems. This paper describes the OFDM transceiver
implementation using software-defined radio system (SDR).
A SDR is a radio communication system where elements have
been generally implemented in hardware are rather
implemented by software on a personal computer. In this paper,
the software part is realized using GNU Radio and the
hardware part is implemented using USRP N210. OFDM poses
a problem of a Peak to Average Power Ratio (PAPR) or high
crest factor. To stave off this problem either High Power
Amplifiers (HPAs) with large dynamic range or PAPR reduction
techniques are used. The former scheme raises cost of the
system, while the latter induces redundancy or distortion.
This paper presents a novel architecture (which combines
channel coding and clipping) for the PAPR reduction and
analyzes various parameters which effects the performance
of OFDM such as power spectral density, the crest factor and
BER. Channel coding part is framed of three steps
randomization, Forward Error Correction (FEC) and
interleaving. In clipping, certain threshold limits the
amplitude of time domain samples. Without filtering, clipping
causes out-of-band radiation. The paper analyzes the out band
radiation value (at 2.395 GHz) and PAPR reduction with respect
to clipping threshold value. This scheme is preferred because
of its lower complexity and hence would be cheaper to
implement than conventional reduction techniques.
Experimental results prove that the clipping method reduced
PAPR significantly as the number of clip and filtering level is
increased.
A Review Paper on: The PAPR Analysis of MIMO-OFDM SystemsIJEEE
Orthogonal frequency division Multiplexing (OFDM) is one of the most popular multicarrier or multiplexing modulation techniques which transmits many signals over a single path in high speed wireless communication. OFDM convert high data rate stream in to smaller data rate stream. Due to this high data rate and ability to combat frequency selective fading, OFDM has a strong candidate for 4G wireless networks. Because of OFDM-MIMO advantages in multipath fading channel e.g. stout against ISI, ICI and some other advantages like best QoS for multiple users, efficient convention of bandwidth it is suggested to be the modulation technique for next generation 4G networks e.g. LTE. OFDM combined with multiple-input multiple-output (MIMO) to increase system capacity over the time variant frequency-selective channels and the diversity gain. The radio transmitter stations for covering and getting enough transmitted power in their desired area has to use High Power Amplifier (HPA) operable near to the saturation region or else, an aspect memory-less nonlinear distortion will affect the communication path. But along with all its advantages there are some disadvantages also. e.g. High PAPR (Peak to Average Power Ratio) at the transmitter end and BER (Bit Error Rate) at the receiving end. As OFDM is only used in the downlink of 4G networks. To reduce the problems of OFDM-MIMO systems some procedures as SLM, PTS, Clipping, Coding, & Pre-coding etc are suggested but none of them is proficient enough to reduce the PAPR and BER up to standard value. This Paper will discuss some techniques of PAPR reduction, and both their advantages and disadvantages.
A review paper on the papr analysis of orthogonal frequency division multiple...ijmnct
OFDM (Orthogonal Frequency Division Multiplexing) has been raised a new modulation technique. Due
to its advantages in multipath fading channel e.g. robust against ISI, ICI and some other advantages like
best QoS for multiple users, efficient usage of bandwidth it is suggested to be the modulation technique for
next generation 4G networks e.g. LTE. But along with all its advantages there are some disadvantages also
e.g. High PAPR (Peak to Average Power Ratio) at the transmitter end and BER (Bit Error Rate) at the
receiving end. Since OFDM is only used in the downlink of 4G networks. To reduce the problems of OFDM
some techniques e.g. SLM, PTS, Clipping, Coding, & Pre-coding etc are suggested but none of them is
reduce the PAPR and BER to an acceptable value. This Paper will discuss some techniques of PAPR &
BER reduction, and their advantages and disadvantages in detail.
DYNAMIC OPTIMIZATION OF OVERLAPAND- ADD LENGTH OVER MBOFDM SYSTEM BASED ON SN...cscpconf
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
Similar to PAPR REDUCTION AND BIT ERROR RATE EVALUATION IN OFDM SYSTEM USING HYBRID TECHNIQUES (20)
An Optimized Mechanism for Adaptive and Dynamic Policy Based Handover in Clus...pijans
On-going revolution in ever-improving wireless communication enforces the necessity of a self configuring,
rapidly deployable and infrastructure less network. MANET is such an autonomous wireless network that
meets the requirements. At the same time MANET’s random behavior and absence of any central
intelligence to gather unambiguous knowledge about user contexts complexes QoS maintenance and
hampers proper utilization of network resources resulting into unnecessary handovers. In past, few policy
driven handover approaches have been proposed for MANET but none of them explores a comprehensive
policy design. Therefore in this paper we propose an adaptive and optimized policy based handover
mechanism which is based on explicitly designed policies like load balancing, service discovery and next
hop selection .Efficient procedures for these policies are also explored .This work predicts the high time of
handover need on the basis of application specific needs of individual freely roaming mobile nodes,
avoiding unnecessary handovers and provides efficient handover procedure with optimized resource
consumption, reduced latency and interruption time.
An Efficient Routing Protocol for Mobile Ad Hoc Network for Secured Communica...pijans
Security and reliable communication is challenging task in mobile Ad Hoc network. Through mobility of network device compromised with attack and loss of data. For the prevention of attack and reliable communication, various authors proposed a method of secured routing protocol such as SAODV and SBRP (secured backup routing protocol). The process of these methods work along with route discovery and route maintains, discovery and route maintained needed more power consumption for that process. The power of devices is decrease during such process and network lifetimes expire. In this paper, we modified the secured stateless protocol for secured routing and minimized the utilization of power during path discovering and establishment. For the authentication of group node used group signature technique and sleep mode threshold concept for power minimization. Our proposed technique is simulated in ns-2 and compare to other routing protocol gives a better performance in comparison to energy consumption and throughput of network.
As-Puma : Anycast Semantics In Parking Using Metaheuristic Approachpijans
The number of vehicle used in the world are increasing day by day resulting in the obvious problem of
parking of these vehicle’s in residential and vocational areas. We perceive the problem of vehicles parking
in vocational establishments / malls. Today majority of parking systems are manual parking systems where
in, on the spot, parking of the vehicle is done and a parking slip is generated and handed over to customer.
This is cumbersome technique wherein various parking attendants in the parking areas manually keeps on
informing the Parking inspector on how many free parking slots available so that only that many number of
parking slips/tickets are generated as the number of free parking slots. We address the problem of parking
in Delay Tolerant Network (DTN) by proposing metaheuristic driven approach of Ant Colony optimization
(ACO) technique with anycast semantics models . Here we propose the parking architecture to solve the
problem of parking especially in commercial areas with their design diagrams . In this architecture we
apply the delivery model to deliver the packet correctly to the intended receiver. Using this we can book
various parking’s through remote areas so that the customer can get the information about availability of
various parking’s inside an area and the parking fare for each category of the automobile. Using this
architecture the customer can get the prior knowledge about various vacant parking slots inside a parking
area and he can book the corresponding parking from his location.
A Survey of Enhanced Routing Protocols for Manetspijans
Mobile Ad Hoc Networks (MANETs) form a class of dynamic multi-hop networks consisting of a set of
mobile nodes that intercommunicate on shared wireless channels. MANETs are self-organizing and selfconfiguring multi-hop wireless networks, where the network structure changes dynamically due to the node
mobility. There exists no fixed topology due to the mobility of nodes, interference, multipath propagation
and path loss. Hence efficient dynamic routing protocols are required for these networks to function
properly. Many routing protocols have been developed to accomplish this task. In this paper we survey
various new routing protocols that have been developed as extensions or advanced versions of previously
existing routing protocols for MANETs such as DSR, AODV, OLSR etc.
Black Hole Attack Prevention Using Random Dispersive Routing for Mobile Adhoc...pijans
Mobile Adhoc Networks is a wireless network and it has become an important technology in current years
in which security has become an important problem. Black hole Attack is one of the promising and severe
security attacks in mobile ad hoc networks which block the communication of secret data during packet
delivery. Black hole attack directly attacks the node’s data traffic on the path and with intent drops, alters
or delays the data traffic passing through that node. In other type of black hole attack which misleadingly
replies for the route request which comes from the node which initiates the route discovery process that it
has as much as necessary routes to the destination even it does not have path to the destination. This paper
deals with prevention of black hole attacks using Shamir’s secret sharing and Random Multipath Routing
Algorithm
Performance Analysis of Mtpr Routing Protocol in Power Deficient Nodepijans
Power conservation in Mobile Ad hoc Network (MANET) is a major challenge even today for researchers.
To conserve it various power aware routing protocols have been proposed. These protocols do not take into
consideration the residual power left in nodes. To find the impact of the same a simulator was designed in
MATLAB-7.01. The routing protocol used in our simulation is Minimum Total Power Routing (MTPR) and
different performance metrics such as path optimality, throughput and hop count were recorded in
presence and absence of power scarce node. The result shows significant impact of power scarce node on
MANET performance.
Path Duration Analysis in Vehicular Ad Hoc Networkpijans
In Vehicular Ad hoc Networks (VANETs) the mobility of the nodes is the main concern. This mobility of
nodes makes the route unstable and unreliable for the information exchange and communication between
two nodes in the network. To enhance the performance and throughput of the VANETs, routes between
nodes must be reliable and stable. In this paper, we study the significance of path duration and link
duration in Vehicular Ad hoc Networks (VANETs). Because of this mobility, connectivity graphs changes
very frequently and it affects the performance of VANETs. Therefore, path duration can be used to predict
the behaviour of the mobile nodes in the network. Estimation of the path duration in VANETs can be a key
factor to improve the performance of the routing protocol. Estimation of path duration is a challenging task
to perform as it depends on many parameters including node density, transmission range, numbers of hops,
and velocity of nodes. This paper will provide a comprehensive study for estimating the path duration in
VANETs.
Study of Various Schemes for Link Recovery in Wireless Mesh Networkpijans
As there is a growing need for the cost effective and highly dynamic large-bandwidth networks over large
coverage area , the Wireless Mesh Network provide first step towards effective communication. A Wireless
Mesh Network is one of the most advanced wireless network used for communication. During their
operating period , the wireless mesh network may suffer from frequent link failure which results in poor
performance of network. Link failure detection plays crucial role in performance of WMN. The proposed
paper presents the review of various techniques used for detection of link failure and the techniques used
for recovery of wireless mesh network.
A Survey on Security Issues to Detect Wormhole Attack in Wireless Sensor Networkpijans
Sensor nodes, when deployed to form Wireless sensor network operating under control of central authority
i.e. Base station are capable of exhibiting interesting applications due to their ability to be deployed
ubiquitously in hostile & pervasive environments. But due to same reason security is becoming a major
concern for these networks. Wireless sensor networks are vulnerable against various types of external and
internal attacks being limited by computation resources, smaller memory capacity, limited battery life,
processing power & lack of tamper resistant packaging. This survey paper is an attempt to analyze threats
to Wireless sensor networks and to report various research efforts in studying variety of routing attacks
which target the network layer. Particularly devastating attack is Wormhole attack- a Denial of Service
attack, where attackers create a low-latency link between two points in the network. With focus on survey of
existing methods of detecting Wormhole attacks, researchers are in process to identify and demarcate the
key research challenges for detection of Wormhole attacks in network layer.
This document is Intended for the purpose of Enabling the power of social media to Empower Ridesharing.
this entails the creation of an ad-ridesharing Initiative with a view to tackling real-world problems such as
traffic congestion and the ever-increasing fuel prices. The main objectives include creating applications,
both web and mobile based, to seamlessly integrate the app’s functionality into and everyday user’s
routine.
Performance Analysis of Improved Autonomous Power Control Mac Protocol (IAPCM...pijans
Power Control in Mobile Ad Hoc networks is a critical issue, since nodes are powered by batteries.The
main idea of power control schemes is to use different power levels for RTS/CTS and DATA/ACK. These
schemes may degrade network throughput and reduce energy efficiency of the network. In this paper we
have evaluated the performance of Improved Autonomous Power Control MAC Protocol (IAPCMP),that
allows nodes to dynamically adjust power levels for transmission of DATA/ACK according to the distance
between the transmitter and its neighbors.In IAPCMP power level for transmission of RTS/CTS is also
adjustable. This also used maximum power level for transmitting DATA/ACK periodically to make
neighboring nodes aware about ongoing transmission. The performance of IAPCMP is evaluated through
the metrics namely, packet delivery ratio and rate of energy efficiency.The simulation results show
significant improvement in protocol.
A Survey of Using Directional Antennas in Ad Hoc Networkspijans
In this paper, we present a comprehensive overview on Ad hoc networking by directional antennas. Use of
Directional antennas can largely reduce the interference, increase the spatial reuse and due to their longer
range we can have routes with fewer hop for two distant nodes. However the main problem of using
directional antennas in Ad hoc networks is due to the dynamic nature of the network. Neighbour discovery,
maintenance the track of moving neighbours, exploitation of the benefit of long range and directional MAC
protocols are the most challenging issues. We present three Directional MAC protocols and two
combinational protocols and system which give solutions to MAC and Neighbour discovery and compare
the throughput of them with 802.11 with omnidirectional antennas.
Wireless Evolution: IEEE 802.11N, 802.11AC, and 802.11AX Performance Comparisonpijans
The widespread adoption of IEEE 802.11 WLANs is attributed to their inherent mobility, flexibility, and
cost-effectiveness. Within the IEEE 802 working group, a dedicated task group is diligently advancing
WLAN technologies, particularly tailored for dense network scenarios. Amidst these advancements, the
802.11ac protocols have emerged as a preferred choice, delivering superior data transfer rates compared
to the preceding 802.11n standard. Significantly, the sixth-generation wireless protocol, IEEE 802.11ax,
has been introduced, showcasing enhanced performance capabilities that outpace its fifth-generation
predecessor, 802.11ac.In this pioneering investigation, we engage in an in-depth simulation-based scrutiny
of prominentWLAN protocols—namely, IEEE 802.11n, IEEE 802.11ac, and the cutting-edge IEEE
802.11ax. Our exhaustive analyses traverse a spectrum of critical metrics, encompassing throughput,
coverage, spectral efficiency, Tx/Rx gain, and Tx/Rx power.In a single-user and SISO scenario, both
802.11ac and 802.11ax outperform 802.11n. Significantly, 802.11ax surpasses the previous 802.11n/ac
standards, highlighting substantial advancements in wireless performance.
Performance Improvement of Multiple Connections in AODV with the Concern of N...pijans
Mobile Ad-hoc Networks (MANETS) consists of a collection of mobile nodes without having a central
coordination. In MANET, node mobility and dynamic topology play an important role in the performance.
MANET provide a solution for network connection at anywhere and at any time. The major features of
MANET are quick set up, self organization and self maintenance. Routing is a major challenge in MANET
due to it’s dynamic topology and high mobility. Several routing algorithms have been developed for
routing. This paper studies the AODV protocol and how AODV is performed under multiple connections in
the network. Several issues have been identified. The bandwidth is recognized as the prominent factor
reducing the performance of the network. This paper gives an improvement of normal AODV for
simultaneous multiple connections under the consideration of bandwidth of node.
An Efficient Call Admission Control Scheme for Handling Handoffs in Wireless ...pijans
Personal Communication Network (PCN) is an emerging wireless network that promises many new
services for the telecommunication industry. The proliferation of demands for extending wireless services
to integrated services, which supports the transmission of data and multimedia information, has resulted in
the need for broadband wireless systems that are able to provide service capabilities similar to those of
wire line networks. The ATM cell - relay paradigm is one possible approach to provide broadband wireless
transmission with PCN’s using the ATM switching networks for interconnection of PCN cells. As traffic in
these mobile cellular networks increases, Handoffs will become an increasingly important issue. As cell
sizes shrink to accommodate an increasingly large demand of services, newer more efficient handoff
schemes need to be used. In this paper, the authors describe the use of novel and efficient data structure
which dynamically allocates guard channel for handoffs and introduces the concept of channel borrowing
strategy. The proposed scheme allocates the guard channels for handoff requests dynamically, based on the
traffic load for certain time period. A new originating call in the cell coverage area also uses these guard
channels if they are unused. Our basic idea is to allow Guard channels to be shared between new calls and
handoff calls. This approach maximizes the channel utilization. The simulation results prove that the
channel borrowing scheme improves the overall throughput.
Design and Implementation of Low-Cost Electric Vehicles (EVs) Supercharger: A...pijans
This article presents a probabilistic modeling method utilizing smart meter data and an innovative agentbased simulator for electric vehicles (EVs). The aim is to assess the effects of different cost-driven EV charging strategies on the power distribution network (PDN). We investigate the effects of a 40% EV adoption on three parts of Frederiksberg's low voltage distribution network (LVDN), a densely urbanized municipality in Denmark. Our findings indicate that cable and transformer overloading especially pose a challenge. However, the impact of EVs varies significantly between each LVDN area and charging scenario. Across scenarios and LVDNs, the share of cables facing congestion ranges between 5% and 60%. It is also revealed that time-of-use (ToU)-based and single-day cost-minimized charging could be beneficial for LVDNs with moderate EV adoption rates. In contrast, multiple-day optimization will likely lead to severe congestion, as such strategies concentrate demand on a single day that would otherwise be distributed over several days, thus raising concerns about how to prevent it. The broader implications of our research suggest that, despite initial worries primarily centered on congestion due to unregulated charging during peak hours, a transition to cost-based smart charging, propelled by an increasing awareness of time-dependent electricity prices, may lead to a significant rise in charging synchronization, bringing about undesirable consequences for the power distribution network (PDN).
Design and Implementation of Low-Cost Electric Vehicles (EVs) Supercharger: A...pijans
This article presents a probabilistic modeling method utilizing smart meter data and an innovative agentbased simulator for electric vehicles (EVs). The aim is to assess the effects of different cost-driven EV
charging strategies on the power distribution network (PDN). We investigate the effects of a 40% EV
adoption on three parts of Frederiksberg's low voltage distribution network (LVDN), a densely urbanized
municipality in Denmark. Our findings indicate that cable and transformer overloading especially pose a
challenge. However, the impact of EVs varies significantly between each LVDN area and charging
scenario. Across scenarios and LVDNs, the share of cables facing congestion ranges between 5% and
60%. It is also revealed that time-of-use (ToU)-based and single-day cost-minimized charging could be
beneficial for LVDNs with moderate EV adoption rates. In contrast, multiple-day optimization will likely
lead to severe congestion, as such strategies concentrate demand on a single day that would otherwise be
distributed over several days, thus raising concerns about how to prevent it. The broader implications of
our research suggest that, despite initial worries primarily centered on congestion due to unregulated
charging during peak hours, a transition to cost-based smart charging, propelled by an increasing
awareness of time-dependent electricity prices, may lead to a significant rise in charging synchronization,
bringing about undesirable consequences for the power distribution network (PDN).
Multilayer Perceptron Guided Key Generation through Mutation with Recursive R...pijans
In this paper, a multilayer perceptron guided key generation for encryption/decryption (MLPKG) has been
proposed through recursive replacement using mutated character code generation for wireless
communication of data/information. Multilayer perceptron transmitting systems at both ends accept an
identical input vector, generate an output bit and the network are trained based on the output bit which is
used to form a protected variable length secret-key. For each session, different hidden layer of multilayer
neural network is selected randomly and weights or hidden units of this selected hidden layer help to form
a secret session key. The plain text is encrypted using mutated character code table. Intermediate cipher
text is yet again encrypted through recursive replacement technique to from next intermediate encrypted
text which is again encrypted to form the final cipher text through chaining , cascaded xoring of multilayer
perceptron generated session key. If size of the final block of intermediate cipher text is less than the size of
the key then this block is kept unaltered. Receiver will use identical multilayer perceptron generated
session key for performing deciphering process for getting the recursive replacement encrypted cipher text
and then mutated character code table is used for decoding. Parametric tests have been done and results
are compared in terms of Chi-Square test, response time in transmission with some existing classical
techniques, which shows comparable results for the proposed technique.
Performance Analysis of Mobile Adhoc Network Routing Protocols Over Tcppijans
In order to reduce the communication cost and time we are looking forward for successful implementation
of an infrastructure less network like Mobile Ad Hoc Network in all arena of wireless mobile
communication. But still it is a challenge to decide a most appropriate routing protocol for MANET. In
MANET there is no fixed topology due to the mobility of nodes, interference, multipath propagation and
path loss. Since MANET does not use fixed infrastructure rather it always have to find suitable router and
routing path for each communication, existing established routing protocol is not suitable for MANET to
function properly. Different Routing protocols have been proposed to meet the challenges with MANETs.
This paper evaluates the performances of four MANET routing protocols which are DSDV, AODV, DSR
and TORA over TCP, a Transport Layer Protocol. The performance metrics which are considered in this
paper are packet delivery fractions, normalized routing overload, end to end delay and throughput. DSDV
is a proactive protocol and the others are reactive protocols.
Securing Mobile Ad hoc Networks: Key Management and Routingpijans
Secure communication between two nodes in a network depends on reliable key management systems that generate and distribute keys between communicating nodes and a secure routing protocol that establishes a route between them. But due to lack of central server and infrastructure in Mobile Ad hoc Networks (MANETs), this is major problem to manage the keys in the network. Dynamically changes in network’s topology causes weak trust relationship among the nodes in the network. . In MANETs a mobile node operates as not only end terminal but also as an intermediate router. Therefore, a multi-hop scenario occurs for communication in MANETs; where there may be one or more malicious nodes in between source and destination. A routing protocol is said to be secure that detects the detrimental effects of malicious node(s in the path from source to destination). In this paper, we proposed a key management scheme and a secure routing protocol that secures on demand routing protocol such as DSR and AODV. We assume that MANETs is divided into groups having a group leader in each group. Group leader has responsibility of key management in its group. Proposed key management scheme is a decentralized scheme that does not require any Trusted Third Party (TTP) for key management. In proposed key management system, both a new node and group leader authenticates each other mutually before joining the network. While proposed secure routing protocol allows both communicating parties as well as intermediate nodes to authenticate other nodes and maintains message integrity.
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Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
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ML for identifying fraud using open blockchain data.pptx
PAPR REDUCTION AND BIT ERROR RATE EVALUATION IN OFDM SYSTEM USING HYBRID TECHNIQUES
1. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
DOI: 10.5121/ijans.2022.12301 1
PAPR REDUCTION AND BIT ERROR RATE
EVALUATION IN OFDM SYSTEM USING HYBRID
TECHNIQUES
Dr. Md. Dulal Haque, Md.Milon Rana and Tajkuruna Akter Tithy
Department of Electronics and Communication Engineering,
Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh
ABSTRACT
Orthogonal frequency division multiplexing (OFDM) has become an important component of waveform
generation in wideband transmission. it's a superior technology for the high-speed rate of wired and
wireless communication systems. Currently, multiple-input multiple-output orthogonal frequency division
multiplexing (MIMO OFDM) systems are crucial wireless communication systems like 4G and 5G
networks & tactical communication. The OFDM has many advantages over other techniques like its high
capacity and immunity against multipath fading channels. However, one amongst the foremost drawbacks
of the OFDM system is that the high-peak-to-average power ratio (PAPR) that leads the system to provide
in-band distortion and out-of-band radiation and reduces its efficiency. This problem increases with a rise
within the number of transmit antennas. Therefore, it's highly desirable to cut back the PAPR of an OFDM
signal. For this, numerous techniques are proposed to beat the PAPR problem like i) Selective mapping
(SLM) ii) Partial transmit sequence (PTS), iii) Clipping, iv) Clipping and filtering. All of those are reduced
the PAPR by generating alternative subcarrier vector that are statistically independent OFDM symbols for
a given data frame and transmitting the symbol with rock bottom peak power. During this paper we also
proposed, some hybrid techniques. The hybrid techniques are the technique of clipping is employed in
conjunction with SLM and PTS to cut back computational complexity. And also the combination of SLM-
PTS to scale back PAPR. Simulations are acquainted with analyze the efficiency of the techniques used
which signifies OFDM to be providing much better PAPR reduction and a way better Bit Error Rate
(BER). it's shown in simulation results that the proposed scheme performs well reducing PAPR. But the
proposed scheme is more complex than the prevailing techniques.
KEYWORDS
OFDM, PAPR, SLM, PTS, MIMO, 5G, 4G, HYBRID, BER.
1. INTRODUCTION
In data communications and networking, orthogonal frequency-division multiplexing (OFDM)
could be a method of digital data modulation, whereby one stream of information is split into
several separate sub-streams for transmission via multiple channels. Orthogonal Frequency
Division Multiplexing may well be a Multicarrier transmission technique supported orthogonal
carriers which became one in every of the foremost cheering developments of up thus far
broadband wireless networks and wire line transmission systems due to its high speed data
transmission, great spectral efficiency, fine quality service, robustness to the selective fading
problem and narrow band interference [1].
OFDM uses the principle of frequency division multiplexing (FDM), where the available
bandwidth is split into a group of sub-streams having separate frequency bands .The downlink of
2. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
2
the LTE system is OFDM-based and this might be often so permanent reason. OFDM is
principally utilized in digital audio broad-casting (DAB), digital video broad-casting-terrestrial
(DVB-T), mobile Multimedia access communication (MMAC), IEEE802.11a, IEEE802.16 and
IEEE 802.20[2][3].
OFDM possesses a remarkable characteristic of getting the pliability to be adapted in an
exceedingly very straightforward manner to work in numerous channel bandwidths per spectrum
availability. Another advantage of OFDM is that the low complexity within the planning of the
receiver. Orthogonal frequency division multiplexing (OFDM) underlies all 4G wireless
communication Systems; for example, it's included within the IEEE 802.16 Worldwide
Interoperability for Microwave Access (WiMAX) and future Evolution (LTE) standards. LTE is
currently the chosen standard for interoperable Public Safety communications within the US and
in other countries.[4]
Furthermore, the OFDM system is healthier than other multicarrier techniques because it's unique
features like efficient bandwidth utilization, less vulnerability, and fewer non-linear distortion
.Although OFDM has many distinctive features, the high peak-to-average power ratio(PAPR) is
taken into account because the foremost drawback in OFDM that causes the OFDM system suffer
from in-band distortion and out-of-band radiation [5]. This can be attributed to the non-linearity
nature of the high power amplifier (HPA) within the transmitter. Also, the high PAPR value
increases the complexity when using some devices like analog to digital converter (ADC) and
digital to analog converter (DAC). Hence, the OFDM system requires HPA with large input
back- off power (IBO), and long word length to follow the high PAPR value [6]. These
constraints undoubtedly represent relevant issues that caught the eye of the many researchers.
1.1. Working Principle of OFDM
OFDM could be a specialized FDM having the constraint that the sub-streams within which the
most signal is split, are orthogonal to every other. Orthogonal signals are signals that are
perpendicular to every other. A main property of orthogonal signals is that they are doing not
interfere with one another. When any signal is modulated by the sender, its sidebands detached
either side. A receiver can successfully demodulate the information on condition that it receives
the entire signal. just in case of FDM, guard bands are inserted so interference between the
signals, leading to cross-talks, doesn't occur. However, since orthogonal signals are employed in
OFDM, no interference occurs between the signals whether or not their sidebands overlap. So,
guard bands are often removed, thus saving bandwidth. the standards that must be maintained is
that the carrier spacing should be adequate the reciprocal of the symbol period.
In order that OFDM works, there should be very accurate synchronization between the
communicating nodes. If frequency deviation occurs within the sub-streams, they'll not be
orthogonal from now on, thanks to which interference between the signals will occur.
3. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
3
1.2. Block Diagram of the OFDM System.
Figure 1. Block diagram of the OFDM system.
The OFDM sequence is generated by adding all N modulated subcarriers when applying IFFT
operation, with the consideration; the subcarriers are allowed to be orthogonally one another. to
know the concept of OFDM, let X = is that the complex representation of the pc file block
symbols after constellation mapping operation, where Xk represents the block data of kth
subcarrier, and N is that the quantity of subcarriers. Therefore, the complex baseband OFDM
signal is defined as [7]
𝑥 𝑡 =
1
√𝑁
𝑋𝑘 𝑒𝑗2𝜋𝑘 ∆𝑓𝑡
𝑁−1
𝑘=0
0 ≤ 𝑡 ≤ 𝑇 ----------- (1)
where 𝑒𝑗2𝜋∆𝑓𝑡
is that the factor of the k th subcarrier, T represents the complete time of symbol,
∆f is that the frequency space between subcarriers, and j= √−1 . The bandwidth of the symbol is
B = N. ∆f, and ∆f is about as 1/T to create sure the orthogonally between the subcarriers of the
symbol. Therefore, the baseband OFDM signal is additionally written as
𝑥 𝑡 =
1
√𝑁
𝑋𝑘 𝑒𝑗2𝜋𝑘 𝑡/𝑇 0 ≤ 𝑡 ≤ 𝑇
𝑁−1
𝑘=0 --------------(2)
The baseband OFDM signal is sampled by applying the rate (t = T /N). Therefore, the discrete
OFDM signal within the time-domain are visiting be expressed as,[ 8]
𝑥 𝑛 =
1
√𝑁
𝑋𝑘 𝑒𝑗2𝜋𝑘𝑛 /𝑁 0 ≤ 𝑛 ≤ 𝑁 − 1
𝑁−1
𝑘=0 --------------(3)
4. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
4
where n represents the discrete sampling index, whereas the discrete OFDM signal vector is
written as
𝑥 𝑛 = [𝑥0,𝑥1,𝑥2,………….. 𝑥𝑁−1]𝑇
---------------- (4)
The original OFDM signal is
Figure 2. Original OFDM signal.
1.3. Application of OFDM
OFDM is used in the following area –
Wi-Fi
DSL internet access
4G wireless communications
digital television
radio broadcast services
1.4. Objectives
The provided solution is that the reduction of PAPR. additionally, variety of techniques are found
within the literature belonging to different categories like clipping, clipping and filtering
techniques, SLM & PTS [10]. Probably the simplest technique to combat PAPR in OFDM signal
is by using clipping, clipping and filtering [11]. Other techniques are supported multiple signal
representation techniques or probabilistic techniques like selected mapping (SLM) technique
.These methods act on the phase of the information sub-carriers so as to mitigate the PAPR.
However, as clipping could be a non-linear method, it should generate in-band (IB) distortion
[12] or out-of-band (OOB) radiation [13], which degrades the BER, breaks the signal down or
disturbs the adjacent channel. Nevertheless, such effects are often mitigated when filtering is
employed after clipping. Conversely, SLM has disadvantaged because of multiple inverse fast
Fourier transform (IFFT) blocks and the computational complexity, which is directly proportional
to the scale of the phase vector matrix required to realize the most effective PAPR performance
[14].On the opposite hand, Partial Transmit Sequence (PTS) has been the most promising one
because of its good PAPR reduction capability without restriction on the amount of subcarriers
[15]. In PTS, the data block which is split into disjoint sets called subblocks and also the
subblocks are combined followed by multiplication of a phase vector. In PTS, design of the
optimal transmit phase selection of the optimum phase vector from a group of known solutions is
5. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
5
most challenging [16]. Furthermore, some ordinary techniques are introduced and discussed in
terms of PAPR and Bit error rate (BER).These are the hybrid techniques .In this paper we also
discuss hybrid techniques like others technique
2. OVERVIEW OF PAPR
High PAPR has been cited jointly of the drawbacks of the OFDM modulation format. In RF
systems, the most important problem resides within the power amplifiers at the transmitter end,
where the amplifier gain will saturate at high input power. a technique to avoid the relatively
“peaky” OFDM signal is to work the ability amplifier at the so-called heavy “back off” regime
where the signal power is way below the amplifier saturation power. Unfortunately, this needs an
excess large saturation power for the facility amplifier, which inevitably ends up in low power
efficiency. within the optical systems, the optical power amplifier (predominately erbium-doped
amplifiers are currently in use) is ideally linear irrespective of its sign power because of its slow
reaction time on the order of milliseconds. Nevertheless, PAPR still presents a challenge for glass
fiber communication thanks to the glass fiber nonlinearity. [17]
This ratio of the height to average power value is termed as Peak-to-Average Power Ratio.
Coherent addition of N signals of the identical phase produces a peak which is N times the typical
signal. [18]
The high PAPR of OFDM implies that if the signal isn't to be distorted, many of the components
within the transmitter and receiver must have a good dynamic range. The output amplifier of the
transmitter must be very linear over a large range of signal levels. in an exceedingly wireless
system, the expense and power consumption of those amplifiers are often the important design
constraints. Moreover, the presence of an oversized number of subcarriers with varying
amplitudes leads to a high peak-to-average power ratio of the system (OFDM) and has
implications within the efficiency of the often ness amplifier. This degrades the bit error rate and
increases the price of the system.[19]
To respond to the above-mentioned problems, different methods and techniques were proposed
by researchers like coding techniques, tone injection, filtering, oversampling, and multiple signal
representation. the most purpose of this study is to propose techniques for the reduction of peak-
to-average power ratio in an OFDM system with a stress on the 4G network.[20] PAPR is defined
as:
PAPR=
𝑃𝑀𝐴𝑋
𝑃𝐴𝑉
………………….(5)
Where, Pmax= Maximam power of the signal. Pav=Average power of the signal.
The major disadvantages of a high PAPR are-
1. Increased complexity within the analog to digital and digital to analog converter.
2. Reduction is an efficiency of RF amplifiers.
2.1. The CCDF of the PAPR
The time domain OFDM signal x(t) could be a number. Assuming that the important and
imaginary parts follow a statistical distribution, with 0.5 variance and nil mean, in agreement
with the central limit theorem when K is sufficiently large, the amplitude of the OFDM signal
6. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
6
|x(t)| becomes a Rayleigh distribution and also the power distribution is exponential . The
cumulative distribution function (CDF) of the amplitude of an indication sample is
F(z) = 1−𝑒−𝑧
------------------(6)
If we assume that the average power of x(t) is equal to one, that is, E|x(t)|2 = 1, the probability
distribution function for PAPR less than a certain threshold value is
Pr(PAPR < z) = (𝐹 𝑧 )𝑘
= (1−𝑒−𝑧
)𝑘
--------------------------------- (7)
However, the performance of PAPR reduction techniques is evaluated, the CCDF of the PAPR is
more frequently used. The probability that PAPR exceeds a threshold value
Pr(PAPR > z) = 1−Pr(PAPR ≤z)
= 1− (1−𝑒−𝑧
)𝑘
2.2. PAPR Reduction Techniques
The PAPR reduction includes many techniques, and it‟s captivated with various factors like
Spectral efficiency, Reduction Capacity, increasing of Transmit signal power, loss in rate,
Computation Complexity, increase in BER, Peak Reduction Carrier. The PAPR reduction
techniques are proposed so as to scale back the PAPR [21] the maximum amount as possible. A
number of them are: „amplitude clipping‟, „clipping and filtering‟, „coding‟, „partial transmit
sequence (PTS)‟, „selected mapping (SLM)‟ and „interleaving‟. These techniques achieve PAPR
reduction at the expense of transmit signal power increase, bit error rate (BER) increase, rate loss,
computational complexity increase, and then on .
2.2.1. Clipping
Amplitude clipping is taken into account the only technique which can be undertaken for PAPR
reduction in an OFDM system. A threshold value of the amplitude is about during this case to
limit the height envelope of the input. [22]A signal having values beyond this pre-determined
value is clipped and therefore the rest are allowed to experience undisturbed.
B(x)=
𝑋 𝑥 ≤ 𝐴
𝐴𝑒𝑗∅ 𝑥 ,
𝑋 > 𝐴
where,
B(x) = the amplitude value after clipping.
x = the initial signal value.
A = the edge set by the user for clipping the signal.
2.2.2. Clipping and Filtering
To reduce the out-of-band distortion, the filtering operation is introduced. Clipping and filtering
technique for PAPR reduction is employed. the matter, during this case, is that amplitude clipping
distortion is observed within the system which may be viewed as another source of the noise.
This distortion falls in both in-band and out–of–band. Filtering can not be implemented to cut
back the in-band distortion and a blunder performance degradation is observed here. On the
7. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
7
opposite hand, spectral efficiency is hampered by out – of – band radiation. Out – of – band
radiation may be reduced by filtering after clipping but this could lead to some peak regrowth.
Repeated filtering and clipping operations are often implemented to resolve this problem. the
specified grade is just achieved after several iterations of this process.[23]
2.2.3. Coding
In the coding technique, some code words are wont to reduce the PAPR of the signal. It doesn't
cause any distortion and no out-of-band radiation production, but it's a drawback of reduced
bandwidth efficiency because the rate is reduced. It also suffers from complexity issues, because
it requires large memory for locating the most effective codes and to store large lookup tables,
especially for an oversized number of subcarriers [24].
2.2.4. Selective Mapping
Selected Mapping (SLM) is an efficient method for peak to-average power ratio reduction in
OFDM systems. In SLM technique the info sequence is multiplied with each phase sequences
generated. Thus sequences that carry the identical information are formed. From these signals the
signal with minimum PAPR is chosen for transmission .In SLM technique the initial data block
is multiplied with L phase sequences. Thus L sequences which carry the identical information are
generated. And from the generated L sequences the sequence with minimum P APR is chosen for
transmission. together with the information the side information is additionally transmitted . Side
information indicates the phase sequence which minimized the PAPR.
Figure 3. Block diagram of SLM Technique
2.2.5. Partial Transmit Sequence (PTS) Technique
It is the foremost efficient technique to cut back PAPR. during this technique, blocks of
information is partitioned into no overlapping sub-blocks. This technique is that the modified
technique of selective mapping scheme. There are three partitioning methods for PTS scheme:
8. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
8
Adjacent, interleaved and pseudorandom. Pseudorandom partitioning provide better PAPR
performance among of these schemes. [25]
Figure 4. Block diagram of PTS scheme.
Partial Transmit Sequences (PTS) generates a proof with a coffee PAPR through the addition of
appropriately phase rotated signal parts. The below figure shows the diagram of the partial
transmit sequence (PTS) technique. The signal to be transmitted is partitioned into disjoint sub-
blocks X v, of length which is represented by the vector as
x= 𝑥𝑣
𝑣
𝑣=1 ……………………..(7)
Where, is that the number of subcarriers and V is that the number of sub-blocks. Complex phase
factors,
𝑏𝑣
=𝑒𝑖𝜑𝑣
, 𝜑𝑣𝜖 0,2𝜋 𝑎𝑛𝑑 𝑣 = 1,2, … . . , 𝑉 ………… (8)
are introduced to mix the PTS‟s within the diagram. All subcarriers positions which are occupied
in another sub-block are set to zero. An IFFT is performed on each sub-block, which are then all
summed together to make a possible transmit symbol as:
X=IFFT { 𝑏𝑣
𝑥𝑣
𝑣
𝑣=1 }= bv
IFFT[𝑥𝑣
]
𝑣
𝑣=1 …………..(9)
The phase vector is chosen in order that the PAPR are often minimized, which is shown as:
[𝑏1
… . , 𝑏𝑣
] = [
𝑏1,……,𝑏𝑣
arg min
𝑏𝑣
𝑥𝑣
(𝑛)]
𝑣
𝑣=1
n=0,1,,,,,Nc−1
max
……………. (10)
Then, the corresponding time-domain signal with all-time low PAPR vector may be expressed as:
𝑥 = 𝑏𝑣
𝑣
𝑣=1 𝑥𝑣………………… (11)
X2
bM
b2
Side information
9. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
9
The receiver must have knowledge about the generation process of the transmitted OFDM to
recover the received data for PTS approach. The phase factors must then be transmitted as side-
information that the data is decoded.[26] noted that the quantity of angles should be kept low to
stay the side information to a minimum. If each phase rotation is chosen from a collection of
admissible angles, then the desired number of bits for side information is bits per OFDM symbol.
The computational complexity of PTS method depends on the amount of phase rotation factors
allowed. the choice of the phase factors is restricted to set of elements number to scale back the
search complexity[27]. The sets of phase factors should be searched to seek out the optimum set
of phase vectors. Furthermore, the search complexity increases exponentially with the amount of
sub-blocks and also depends on the sub-block partitioning.
The concept of the PTS technique is to partition the computer file symbols into the disjoint
subsets and these subsets are rotated with different rotation factors. After that, the modified
partitioned subsets are combined again to come up with set of the candidate signals named partial
transmit sequences (pts). Finally, one among candidate sequence which has the minimum PAPR
value is chosen for transmission. within the PTS technique, the amount of the inverse fast Fourier
transform (IFFT) blocks is that the same because the number of subsets. The PTS technique can
do better PAPR reduction performance than the opposite probabilistic techniques like selective
mapping (SLM) and interleaving techniques [28].
However, the PTS technique holds a high computational complexity when finding the optimum
rotation factor and desires to send side information (SI) as index information so as to recover the
first data at the receiver side [29]. On the opposite hand, PTS is considered a distortion less
method because it relies on the scrambling signal technique to scale back the PAPR value. Hence,
PTS considers a probabilistic method to cut back the PAPR of the OFDM signal. Therefore, the
PTS method doesn't suffer from the bit error rate (BER) degradation or the facility signal
distortion.
3. HYBRID TECHNIQUES FOR REDUCING PAPR
In recent years, some hybrid methods have also been proposed. These schemes combine two or
more methods for PAPR reduction, and can be categorized into: Coding plus Multiple Signaling
and Probabilistic techniques (C+MSP), Coding plus Signal Distortion techniques (C+SD),
Multiple Signaling and Probabilistic plus Signal Distortion techniques (MSP+SD), and a
combination of three methods, i.e., Coding plus Multiple Signaling and Probabilistic plus Signal
Distortion techniques (C+MSP+SD) .In this paper ,we combine MSP to MSP(PTS & SLM) ,SD
signal to MSP (PTS & CLIP ,SLM & CLIP).
3.1. Combination Of Clipping and SLM
SLM achieves good PAPR reduction performance at the value of additional high computational
complexity while clipping has moderate complexity but with nonlinear process and in-band
distortion. to make an honest balance between performance and complexity, a unique PAPR
reduction technique is proposed supported combining SLM and clipping method[30].The
diagram of the SLM-clip method is shown in Fig.
10. International Journal on AdHoc Networking Systems (IJANS) Vol. 12, No. 3, July 2022
10
Figure 5. Block diagram of SLM and clipping method
Firstly, the PAPR of input OFDM signals are compared with a preset threshold, so on whether
the operation of SLM is required. If the PAPR exceeds the preset threshold, SLM is
performed. Then, clipping is performed to the last word signal [31]. The SLM-clip technique is
summarized as following.
1) Calculating the PAPR of the input OFDM signal.
2) Compare the PAPR with the preset threshold.
3) If the PAPR is smaller than 1, directly proceed to step 4, else execute the SLM operation.
4) Executing the clipping operation to manage the PAPR of the last word signal.
3.2. Combination of Clipping and PTS
This method works same as SLM-clip technique as discuses above. Instead of SLM, PTS
operation has to be performed [32]. The diagram of the PTS-clip method is shown in Fig
Figure 6. Block diagram of PTS and clipping method
PTS-clip technique is summarized as follows:
1) Calculate the PAPR of the input OFDM signal.
2) Compare the PAPR with the preset threshold.
3) If the PAPR is smaller than 1, directly proceed to step 4; else execute the PTS operation.
4) Executing the clipping operation to control the PAPR of the ultimate signal [33].
3.3. Combination of SLM and PTS
Another hybrid technique which relies on the SLM and PTS schemes, which supply better PAPR
reduction performance than all others schemes which is discussed during this paper. The
proposed scheme is essentially a mix of SLM and PTS schemes. within the proposed scheme first
SLM scheme is applied and that we select the most effective combination of phase sequence and
input file which provides minimum PAPR. Now for further reduction of PAPR, we apply this
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mixture of phase sequence and input file to PTS scheme which further reduces the PAPR. The
proposed scheme may be described by the diagram shown in figure [34]
Figure 7. Block diagram of PTS and SLM method
The Proposed method can be described in following steps[35]:
• Multiply the input data signal with U different phase sequences.
• Generate the OFDM signal for each signal (U signals).
• Select the OFDM signal with lowest PAPR i.e. xu .
• Select corresponding combination of phase sequence and input data i.e. X u .
• Apply X u as an input to PTS scheme.
• Obtain signal with reduced PAPR after applying the PTS scheme.
The receiver has to know which sequence and phase factor was used to generate the signal, so
that it can recover the original data, and the used sequence and phase factor can be transmitted as
side information.[36]
4. RESULTS & DISCUSSION
The result represents the bit error rate with respect to the signal to noise ratio (SNR) Which is
simulated in MATLAB. In figure -8 ,it describe the bit error rate for normal OFDM signal .Figure
9,10,11,12,13 that all represent also the bit error rate for SLM modified signal ,Clipped signal
,Clipped & Filtered signal and Partial Transmit Sequence (PTS) signal and also represents the
BER of all techniques. Figure -14, which represents the CCDF of all techniques. Figure -15
denotes PAPR for Clip, PTS, SLM .Figure -16 express PAPR for Hybrid Techniques. Finally
Figure -17: Comparing PAPR for all Techniques. Figure 18,19,20,21 sequentially represents the
BER of hybrid techniques as well.
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Figure 8. Bit error rate of OFDM signal.
Figure 9. Bit error rate of SLM modified signal.
Figure 10. Bit error rate of clipped OFDM signal.
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Figure 11. Bit error rate of clipped & filtered OFDM signal.
Figure 12. Bit error rate of PTS signal.
Figure 13. Comparing Bit error rate of all techniques.
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Figure 14. CCDF for Calculating PAPR.
Figure 15. PAPR for Clip, PTS, SLM .
Figure 16. PAPR for Hybrid Techniques.
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Figure 17. Comparing PAPR for all Techniques.
Figure 18. BER of Hybrid Technique CLIP+PTS.
Figure 19. BER of Hybrid Technique PTS+SLM.
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Figure 20. BER of Hybrid Technique CLIP+SLM.
Figure 21. BER of Hybrid Techniques.
5. CONCLUSION
OFDM could even be a very attractive technique for multi-carrier transmission and has become
one in every of all the standard choices for top-speed data transmission over-communicating. Its
various advantages; but also has one major drawback: it is a very high PAPR. During this
project, the varied properties of an OFDM System are analyzed then the benefits, and
drawbacks of this method is believed. The bit - error -rate is additionally plotted against the
signal/noise ratio to know the performance of the OFDM system. we've also geared toward
investigating the planning of the techniques which are in commonly accustomed chop back the
high PAPR of the system. Among the three, techniques we revealed that Amplitude Clipping and
Filtering finally, find in Data Loss, whereas, Selected Mapping (SLM) and Partial Transmit
Sequence (PTS) don, 't affect the data. From the comparison curve of all techniques, we could
infer that PTS are often a smaller amount complicated in PAPR reduction.
Some hybrid techniques are also discussed here to reduce PAPR. These techniques are SLP with
Clip, PTS with Clip and PTS with SLM. This techniques are more effective to reduce PAPR
among other techniques like PTS, SLM and Clipping as well. But These Techniques are more
complex and its high cost to installed.
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AUTHORS
Dr. Md. Dulal Haque, Associate Professor, Department of Electronics and
Communication Engineering (ECE), Faculty of Computer Science and Engineering,
Hajee Mohammad Danesh Science & Technology University, Dinajpur. His research
interest is Photoluminescence Characterization of Non-radiative Recombination
Centers, Semiconductor materials and Electronics device
Md. Milon Rana received the B. Sc. (Engineering) from the department of
Electronics and Communication Engineering (ECE), Hajee Mohammad Danesh
Science and Technology University (HSTU), Dinajpur-5200, Bangladesh in 2019.
Currently, He is a student of M. Sc. (Engineering) in the same department. His
research interest is performance analysis of communication protocols of IoT, Machine
Learning, Deep Learning, OFDM ,PAPR..
Tajkuruna Akter Tithy received the B. Sc. (Engineering) from the department of
Electronics and Communication Engineering (ECE), Hajee Mohammad Danesh
Science and Technology University (HSTU), Dinajpur-5200, Bangladesh in 2019.
Currently, she is a student of M. Sc. (Engineering) in the same department. Her
research interest is performance analysis GSM, OFDM, PAPR.