This document summarizes a study that proposes a novel partial transmit sequence (PTS) technique combined with particle swarm optimization (PSO) to reduce peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The standard PTS method divides input data into sub-blocks and applies phase rotation factors to minimize PAPR. The proposed method uses PSO to efficiently explore optimal phase factor combinations and greatly reduces computational complexity and PAPR compared to standard PTS. Simulation results show the proposed PSO-PTS approach significantly lowers complexity while still achieving good PAPR performance.
The increasing demand of ubiquitous multimedia service forces the future wireless communication for higher data rates to the dynamic wireless environment. Orthogonal Frequency-Division Multiplexing (OFDM) is the most common technique has received more attention due to its high spectral efficiency and its resistance to multipath fading in addition to high data rate and robust performance. Presence of large number of subcarriers leads to a large dynamic range with large Peak to Average Power Ratio (PAPR) in OFDM. High PAPR is the major limitation of OFDM in the present scenario. The present research work utilizes conic and convex optimization filtering techniques in customized formulations. The first proposed technique uses Standard Deviation based Iterative Clipping and Filtering (SD-ICF) to minimize PAPR. The filtering simply removes the out-of band spectral re-growth without considering the effect on the time domain peak after the IFFT operation. The main aspect of the SD-ICF approach is that, oversampling increases the resolution of the OFDM symbol giving a closer approximation to the band limited signal after filtering. As a result, it tends to cause sizable time-domain peaks, requiring clipping and filtering to be repeated many iterations before achieving the desired PAPR. The filter response is modified by exploiting convex optimization. As the PAPR is reduced to an optimized value, the effect of oversampling is also minimal. The second approach utilizes a Custom Optimized Iterative Adaptive Clipping and Filtering (COIACF) technique for PAPR reduction. COIACF minimizes PAPR to a desired level in less number of iterations. Moreover, COIACF include an Improved FFT-based method of constructing the linear system of equations, an improved update procedure to reduce the number of iterations. The proposed method shows a greater reduction in PAPR in lesser iterations with reduced out-of-band distortion and bit error rate. Here COIACF uses FFT to reduce the number of iterations. The third proposed Tone Reservation (TR) based technique utilizes the few unused OFDM subcarriers. There are unused subcarriers called Peak Reduction Carriers (PRCs) which are reserved to minimize the BER of the transmitted OFDM signal.TR method is combined with customized convex optimization minimizes the PAPR and BER at a lower computational cost.
Reducing the Peak to Average Power Ratio of Mimo-Ofdm SystemsIJCNCJournal
In this paper, we proposed a particle swarm optimization (PSO) based partial transmit sequence (PTS)
technique in order to achieve the lowest Peak-to-Average Power Ratio(PAPR) in Multiple Input Multiple
Output- Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems. Our approach consist of
applying the PSO based PTS on each antenna of the system in order to find the optimal phase factors,
which is a straightforward method to get the minimum PAPR in such a system. The simulation results
demonstrate that the PSO based PTS algorithm when applied to MIMO-OFDM systems with a wide range
of phase factors, tends to give a high performance. In addition, there is no need to increase the number of
particles of the PSO algorithm to enhance the performance of the system. As a result of this, the complexity
of finding the minimum PAPR is kept at a reasonable level.
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.
The increasing demand of ubiquitous multimedia service forces the future wireless communication for higher data rates to the dynamic wireless environment. Orthogonal Frequency-Division Multiplexing (OFDM) is the most common technique has received more attention due to its high spectral efficiency and its resistance to multipath fading in addition to high data rate and robust performance. Presence of large number of subcarriers leads to a large dynamic range with large Peak to Average Power Ratio (PAPR) in OFDM. High PAPR is the major limitation of OFDM in the present scenario. The present research work utilizes conic and convex optimization filtering techniques in customized formulations. The first proposed technique uses Standard Deviation based Iterative Clipping and Filtering (SD-ICF) to minimize PAPR. The filtering simply removes the out-of band spectral re-growth without considering the effect on the time domain peak after the IFFT operation. The main aspect of the SD-ICF approach is that, oversampling increases the resolution of the OFDM symbol giving a closer approximation to the band limited signal after filtering. As a result, it tends to cause sizable time-domain peaks, requiring clipping and filtering to be repeated many iterations before achieving the desired PAPR. The filter response is modified by exploiting convex optimization. As the PAPR is reduced to an optimized value, the effect of oversampling is also minimal. The second approach utilizes a Custom Optimized Iterative Adaptive Clipping and Filtering (COIACF) technique for PAPR reduction. COIACF minimizes PAPR to a desired level in less number of iterations. Moreover, COIACF include an Improved FFT-based method of constructing the linear system of equations, an improved update procedure to reduce the number of iterations. The proposed method shows a greater reduction in PAPR in lesser iterations with reduced out-of-band distortion and bit error rate. Here COIACF uses FFT to reduce the number of iterations. The third proposed Tone Reservation (TR) based technique utilizes the few unused OFDM subcarriers. There are unused subcarriers called Peak Reduction Carriers (PRCs) which are reserved to minimize the BER of the transmitted OFDM signal.TR method is combined with customized convex optimization minimizes the PAPR and BER at a lower computational cost.
Reducing the Peak to Average Power Ratio of Mimo-Ofdm SystemsIJCNCJournal
In this paper, we proposed a particle swarm optimization (PSO) based partial transmit sequence (PTS)
technique in order to achieve the lowest Peak-to-Average Power Ratio(PAPR) in Multiple Input Multiple
Output- Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems. Our approach consist of
applying the PSO based PTS on each antenna of the system in order to find the optimal phase factors,
which is a straightforward method to get the minimum PAPR in such a system. The simulation results
demonstrate that the PSO based PTS algorithm when applied to MIMO-OFDM systems with a wide range
of phase factors, tends to give a high performance. In addition, there is no need to increase the number of
particles of the PSO algorithm to enhance the performance of the system. As a result of this, the complexity
of finding the minimum PAPR is kept at a reasonable level.
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.
A hybrid of the selected mapping and partial transmit sequence approaches for...CSITiaesprime
The orthogonal frequency division multiplexing (OFDM)-4G and 5G filter
technology suffer a drawback that represents the direction of the peak
average to power ratio (PAPR) in orthogonal frequency division
multiplexing due to the nonlinear nature of the transmitter. There are a lot of
traditional and hybrid methods of these traditional methods to reduce the
harmful high PAPR value. Newly, several new hybrid methods have been
adopted to reduce PAPR but it faces an increasing level of computational
complexity in the system. In this paper, two important and effective
conventional methods for reducing PAPR are studied, analyzed, and
investigated for the hybrid pathway which is the incorporation of selective
mapping (SLM) method and partial transport sequencing (PTS) method,
which achieve increased efficiency of PAPR reduction while computing the
computational complexity of each method. The method depends and
balances with computational complexity. The search is based on multi-carrier connections such as multi carrier-code division multiple access (MC-CDMA) and OFDM.
Peak to Average Power Ratio Reduction in Mc Cdma System by Using Pulse Shapin...IOSR Journals
Abstract: One of the drawback of multicarrier code division multiple access (MC CDMA) is the high peak to
average power ratio (PAPR). In this paper A novel scheme based on pulse shaping described for PAPR
reduction. Here three different pulse shaping filters (Raised cosine, Sinc power pulse and Nyqist pulse) are
described for PAPR reduction in MC CDMA system. The method is based on the proper selection of the pulses
for shaping the different sub carriers of the MC CDMA modulation scheme. It is shown by computer simulation
that the scheme achieves the significant improvement in PAPR reduction in MC CDMA system. Its
implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping
technique can be used not only to shape the spectrum of the transmitted signal but also to reduce its PAPR. In
computer simulation It is observed that by using nyquist pulse near about 6.8 db PAPR is obtained. Which is
considerable PAPR reduction than a PAPR value of Original MC CDMA signal
Keywords: MC CDMA, PAPR, PULSE SHAPING, BPSK
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).
COMPARING VARIOUS CHANNEL ESTIMATION TECHNIQUES FOR OFDM SYSTEMS USING MATLABijwmn
This paper compares the performance of various channel estimation techniques for OFDM systems over quasi-static channels using MATLab. It compares the performance of five channel estimation techniques, these are: decision directed (DD), linear interpolation, second-order interpolation, discrete Fourier transform (DFT) interpolation, minimum mean square error (MMSE) interpolation. The performance is evaluated in terms of two widely-used performance measures, namely, bit-error rate (BER) and the mean square error (MSE) for different levels of signal-to-noise ratio (SNR). The OFDM model is explained and implemented using MATLab to run different simulations. The simulation results demonstrate that the DD channel estimation provides the lowest BER and MSE as compared to interpolation techniques, at the cost of extra processing delay and comparatively sensitive to channel variations between OFDM symbols. Also, the MMSE interpolation outperforms all other interpolation techniques.
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.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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.
ESTIMATION OF SYMBOL TIMING AND CARRIER FREQUENCY OFFSET USING SYNCHRONIZATI...Michael George
OFDM/OQAM is preferred as multicarrier system which operates over a multipath channel. By using the multipath channel the signal-to-noise ratio. In earlier, sub carriers are used to transmit the signals. Nowadays, FFT and DFT are used for transmitting the signals based upon the bit values. AWGN is a channel used to identify the noise produced at the output by adding the noise in the blind signal. By reducing subcarriers the noise and timing are reduced. FFT bit value was increased which provides better performance. In the multicarrier system, the error and noise was reduced by increasing the bit value.
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 low complexity partial transmit sequence approach based on hybrid segmentat...journalBEEI
The partial transmit sequences (PTS) is regarded as a promising scheme for inhibiting the high peak-to-average power ratio (PAPR) problem in the orthogonal frequency division multiplexing (OFDM) systems. The PTS scheme relies on partitioning the data sequence into subsets and weighting these subsets by a group of the phase rotation factors. Although the PTS can efficiently reduce the high PAPR value, a great computational complexity (CC) level restricts the utilization of the PTS scheme in practical applications. In PTS, there are three common types of segmentation schemes; interleaving (IL-PTS), pseudo-random (PR-PTS), and adjacent (Ad-PTS) schemes. This paper presents a new algorithm named hybrid pseudo-random and interleaving cosine wave shape (H-PRC-PTS) by combining the PR-PTS scheme and the symmetrical interleaving cosine wave shape (S-IL-C-PTS) scheme which was proposed in our previous work. The results indicate that the suggested algorithms can diminish the PAPR value like the PR-PTS scheme, whereas the CC level is reduced significantly.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
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.
More Related Content
Similar to PAPR, Spectral Efficiency, BER and SNR Analysis of OFDM: A Novel Partial Transmit Sequence-Particle Swarm Optimization Technique
A hybrid of the selected mapping and partial transmit sequence approaches for...CSITiaesprime
The orthogonal frequency division multiplexing (OFDM)-4G and 5G filter
technology suffer a drawback that represents the direction of the peak
average to power ratio (PAPR) in orthogonal frequency division
multiplexing due to the nonlinear nature of the transmitter. There are a lot of
traditional and hybrid methods of these traditional methods to reduce the
harmful high PAPR value. Newly, several new hybrid methods have been
adopted to reduce PAPR but it faces an increasing level of computational
complexity in the system. In this paper, two important and effective
conventional methods for reducing PAPR are studied, analyzed, and
investigated for the hybrid pathway which is the incorporation of selective
mapping (SLM) method and partial transport sequencing (PTS) method,
which achieve increased efficiency of PAPR reduction while computing the
computational complexity of each method. The method depends and
balances with computational complexity. The search is based on multi-carrier connections such as multi carrier-code division multiple access (MC-CDMA) and OFDM.
Peak to Average Power Ratio Reduction in Mc Cdma System by Using Pulse Shapin...IOSR Journals
Abstract: One of the drawback of multicarrier code division multiple access (MC CDMA) is the high peak to
average power ratio (PAPR). In this paper A novel scheme based on pulse shaping described for PAPR
reduction. Here three different pulse shaping filters (Raised cosine, Sinc power pulse and Nyqist pulse) are
described for PAPR reduction in MC CDMA system. The method is based on the proper selection of the pulses
for shaping the different sub carriers of the MC CDMA modulation scheme. It is shown by computer simulation
that the scheme achieves the significant improvement in PAPR reduction in MC CDMA system. Its
implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping
technique can be used not only to shape the spectrum of the transmitted signal but also to reduce its PAPR. In
computer simulation It is observed that by using nyquist pulse near about 6.8 db PAPR is obtained. Which is
considerable PAPR reduction than a PAPR value of Original MC CDMA signal
Keywords: MC CDMA, PAPR, PULSE SHAPING, BPSK
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).
COMPARING VARIOUS CHANNEL ESTIMATION TECHNIQUES FOR OFDM SYSTEMS USING MATLABijwmn
This paper compares the performance of various channel estimation techniques for OFDM systems over quasi-static channels using MATLab. It compares the performance of five channel estimation techniques, these are: decision directed (DD), linear interpolation, second-order interpolation, discrete Fourier transform (DFT) interpolation, minimum mean square error (MMSE) interpolation. The performance is evaluated in terms of two widely-used performance measures, namely, bit-error rate (BER) and the mean square error (MSE) for different levels of signal-to-noise ratio (SNR). The OFDM model is explained and implemented using MATLab to run different simulations. The simulation results demonstrate that the DD channel estimation provides the lowest BER and MSE as compared to interpolation techniques, at the cost of extra processing delay and comparatively sensitive to channel variations between OFDM symbols. Also, the MMSE interpolation outperforms all other interpolation techniques.
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.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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.
ESTIMATION OF SYMBOL TIMING AND CARRIER FREQUENCY OFFSET USING SYNCHRONIZATI...Michael George
OFDM/OQAM is preferred as multicarrier system which operates over a multipath channel. By using the multipath channel the signal-to-noise ratio. In earlier, sub carriers are used to transmit the signals. Nowadays, FFT and DFT are used for transmitting the signals based upon the bit values. AWGN is a channel used to identify the noise produced at the output by adding the noise in the blind signal. By reducing subcarriers the noise and timing are reduced. FFT bit value was increased which provides better performance. In the multicarrier system, the error and noise was reduced by increasing the bit value.
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 low complexity partial transmit sequence approach based on hybrid segmentat...journalBEEI
The partial transmit sequences (PTS) is regarded as a promising scheme for inhibiting the high peak-to-average power ratio (PAPR) problem in the orthogonal frequency division multiplexing (OFDM) systems. The PTS scheme relies on partitioning the data sequence into subsets and weighting these subsets by a group of the phase rotation factors. Although the PTS can efficiently reduce the high PAPR value, a great computational complexity (CC) level restricts the utilization of the PTS scheme in practical applications. In PTS, there are three common types of segmentation schemes; interleaving (IL-PTS), pseudo-random (PR-PTS), and adjacent (Ad-PTS) schemes. This paper presents a new algorithm named hybrid pseudo-random and interleaving cosine wave shape (H-PRC-PTS) by combining the PR-PTS scheme and the symmetrical interleaving cosine wave shape (S-IL-C-PTS) scheme which was proposed in our previous work. The results indicate that the suggested algorithms can diminish the PAPR value like the PR-PTS scheme, whereas the CC level is reduced significantly.
An Approach to Improve the Quality of Service in OFDMA Relay Networks via Re-...iosrjce
With the next-generation cellular networks making a transition toward smaller cells, two-hop
orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory
component in the 4G standards (WiMAX802.16j, 3GPP LTE-Adv.). Here we are using the multicasting strategy
Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the
latter forms the focus of this project. The main aim of this project is to improve the performance of the OFDMA
based relay networks. The OFDMA transmission Scheme is a widely accepted scheme for improving the quality
and speed of communication over the 4G cellular network. There are two different models designed for OFDMA
relay networks .Distributed (DP) and Contiguous (CP) permutations. We are checking the performance of two
algorithms The linear programming algorithm and the greedy algorithm by using two models of OFDMA for
multicast scheduling and after performance evaluation we select the best model and the algorithm for
transmission. We further improve the throughput via retransmission of lost packets during data transfer over the
specified network. We can detect the packet loss by packet synchronization technique and a request will be sent
by the destination for re-sending the lost packets which is called as Re-Transmission.[1]
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, Spectral Efficiency, BER and SNR Analysis of OFDM: A Novel Partial Transmit Sequence-Particle Swarm Optimization Technique (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.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
DevOps and Testing slides at DASA ConnectKari Kakkonen
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PAPR, Spectral Efficiency, BER and SNR Analysis of OFDM: A Novel Partial Transmit Sequence-Particle Swarm Optimization Technique
1. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
DOI:10.5121/ijans.2023.13402 21
PAPR, SPECTRAL EFFICIENCY, BER AND SNR
ANALYSIS OF OFDM : A NOVEL PARTIAL
TRANSMIT SEQUENCE-PARTICLE SWARM
OPTIMIZATION TECHNIQUE
Karthik Kumar Vaigandla, Ranjith Kumar Siddoju, Madhu Kumar Vanteru,
Malothu Devsingh, Dudimetla Prasad
Department of ECE, Balaji Institute of Technology & Science, Warangal, Telangana,
India
ABSTRACT
Orthogonal frequency division multiplexing (OFDM) is a widely used multicarrier modulation (MCM)
technique in the field of wireless communications, specifically designed to facilitate high-speed data
transmission. The use of several subcarriers inside an OFDM system for the transmission of modulated
symbols results in the generation of OFDM signals with a significant peak-to-average power ratio (PAPR).
In this study, we propose a novel approach for mitigating the high PAPR in wireless communication
systems (WCS). Our method utilizes a partial transmit sequence (PTS) strategy, which is enhanced by
using an adaptive particle swarm optimization (PSO) algorithm. In this study, we present a description of
an OFDM system employing the standard PTS technique in conjunction with PSO. To mitigate
computational complexity, the suggested methodology efficiently explores the optimal amalgamation of
phase rotation components. Experimental findings demonstrate that the computational complexity and
PAPR have been greatly minimized by the suggested method.
KEYWORDS
BER, CCDF, computational complexity, communication, OFDM, PAPR, PTS, PSO, SNR.
1. INTRODUCTION
In nowadays days, the digital landscape is replete with wireless technologies that facilitate the
seamless execution of daily tasks, hence enhancing the quality of life for individuals. The
proliferation of wireless technology has led to a substantial increase in the population's awareness
and proficient use of this technology. The increasing number of active users has led to a strong
demand for services such as high-definition television, mobile video, high-speed internet, and
video conferencing [1-4]. OFDM is widely recognized as a fundamental transmission strategy for
multicarrier (MC) due to its ability to split the channel into sub-channels, enabling parallel data
transfer with extended symbol lengths. This characteristic makes OFDM a highly efficient and
straightforward option for wideband communication. The problem of estimating inter-symbol
interference (ISI) is addressed, and a method is proposed to transform a specified frequency
fading channel into a flat fading channel [5-6]. One of the MCM techniques often employed in
wireless communications is OFDM [7]. The use of the OFDM technique is a common strategy in
achieving high-speed transmission across frequency-selective fading channels [9]. OFDM signals
commonly demonstrate amplitude variation in the time domain and possess a notable dynamic
range, also known as PAPR, owing to their MC structure [8], as the PAPR of an OFDM signal is
high, it undergoes clipping as it passes through a nonlinear high power amplifier (HPA). This
2. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
22
results in a decrease in performance and leads to the generation of out-of-band (OoB) radiation
and in-band distortion. Therefore, the use of expensive linear HPA with a wide dynamic range is
important for OFDM transmitters [10]. An elevated PAPR has a detrimental effect on the
efficiency of radio-frequency (RF) power amplifiers, resulting in increased costs. Numerous
approaches have been developed to mitigate the disadvantages associated with high PAPR. In the
context of OFDM systems, there exist many techniques aimed at reducing the PAPR. These
methods encompass clipping, coding, non-linear companding, tone reservation (TR) and
injection, selective mapping (SLM), and PTS [11]. Among the many ways, the PTS approach
emerges as the most successful and distortion-free technique for minimizing PAPR in OFDM
systems. One of the most effective techniques for reducing PAPR is PTS. One of the challenges
associated with the PTS strategy is its significant computational burden in establishing the
optimal phase factors. Additionally, the requirement to give an excessive amount of phase factors
as side information to the receiver side poses another issue [12]. The optimal selection of phase
factors was achieved by the application of several optimization approaches, including PSO,
Simulated Annealing (SA), Genetic Algorithms (GA). These strategies were employed to
overcome the restrictions associated with the use of PTS [13]. In the PTS technique, the input
data block is divided into many distinct sub-blocks, each of which is independent. Prior to
multiplying each related time signal with a phase rotation factor, an IFFT operation is performed
on each independent sub-block. The objective of the PTS approach is to select appropriate phase
factors in order to minimize the PAPR of the combined signal generated by all sub-blocks [14].
The complexity of conducting an exhaustive search for the optimal phase factors in the PTS
technique increases fast due to the number of sub-blocks and phase rotation variables involved.
Previous studies [15-17] have examined many suboptimal ways to minimize the search
complexity in the context of PTS.
The PSO-PTS Scheme utilized in the OFDM system, as described in the work of Wen, Horng, et
al. [18], utilizes heuristic techniques to determine the optimal combination of basic phase
variables. This approach leads to a decrease in computational complexity, but with a little trade-
off of increased PAPR. In their study, the researchers in reference [19] introduced an OFDM
system that utilizes a sub-optimal PTS technique based on PSO to determine the ideal phase
weighting factors. The results produced from this approach demonstrated good performance in
terms of PAPR and computational complexity, while using only a limited number of iterations.
Additionally, authors worked on the PTS-OFDM technique in [20], which provided a novel
strategy for reducing computational complexity using PSO, with the approach's output coming
close to being achieved but requiring the use of PAPR. The lower PAPR received, but the
complexity load was still somewhat above average, in accordance with GA-PTS and partheno-
crossover operator combination(PCGA)[21]. Additionally, the GA and Optimization algorithms
in PTS-OFDM were analyzed, and the results indicated that while the GA reduced PAPR at the
expense of computational complexity, the PSO approach achieved the vice versa[23]. The reader
may read [24] for more details on another approach called fireworks algorithm (FWA) that
outperformed the two techniques mentioned above. PSO and GA were suggested as some
evolutionary PTS-based optimization techniques for lowering search numbers[22]. In order to
solve the computationally challenging PAPR minimization problem in the PTS technique, a novel
PSO-based approach is presented in this article. The suggested approach decreases PAPR with a
better convergence rate and a reduced computational complexity.
The remaining of the article is arranged as follows. The OFDM transceiver model is described in
Section 2. The PSO algorithm and PTS approach are described in Section 3. Section 4
summarizes the discussion and simulation outputs. Section 5 provides conclusions.
3. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
23
2. OFDM SYSTEM MODEL
All the telecommunications standards, such as those for WLANs, DTT, and DRT in much of the
world, are based on OFDM, a Commonly employed modulation and multiplexing
technology[25]. The literature has referred to OFDM in the past and present as MC, Multi-tone,
and Fourier Transform. The idea of OFDM is to distribute the data to be broadcast among a lot of
carriers that are all modulated at a low rate. By carefully deciding on their frequency spacing, the
carriers are made orthogonal to one another[26]. The complete amount of spectrum bandwidth is
divided into sub-bands using a multicarrier system like FDM so that many carriers can broadcast
simultaneously. It creates a composite high speed communication system by combining a lot of
low data rate carriers [27]. The carriers can be tightly spaced with overlapping and no ICI
because of orthogonality. The need for greater data rate services, such as multimedia, audio, and
data across wired and wireless lines, is rising along with communications technologies. To
transport the vast quantity of data that conventional approaches cannot handle, new modulation
methods are needed. High data rate, acceptable bit error rate(BER), and more latency must be
provided by these methods[28]. One of them is OFDM. In Europe, OFDM has been utilized for
large data rate wired networks like ADSL, DAB, and DVB.
Figure 1. Signals of various frequencies are added via an OFDM modulator
An effective modulation scheme named OFDM is employed in current wireless communication
systems, such as 5G. The development of a high-speed communication system involves the
integration of FDM and QAM in the OFDM technique [29]. BPSK, QPSK, 16QAM, and
64QAM are a few of the various modulation types referred to as QAM. R. W. Chang was the first
to suggest the fundamental idea of OFDM, realizing that band limited orthogonal signals might
be mixed with substantial overlap while minimizing ICI. Using OFDM, we could create a
network of subcarriers that work together to transfer data across several frequencies. These
subcarriers must carry out orthogonal functions. For two functions to be termed orthogonal in
4. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
24
mathematics, the integral of their product over the chosen time range must be zero[29]. In a
broader sense, orthogonal functions can be formed of as statistically unconnected.
The signal representation is given by
1
2
0
( ) k
M
j f t
n
k
s t c e
(1)
Here, fk = f0 + k. ∆f (2)
Figure 1 demonstrates how M subcarriers with identical spacing can be merged to create an array
of parallel signals. QAM is used to modify each subcarrier. Although these modulated subcarriers
can support separate baseband signals, they are often merged to offer the highest data throughput
for a single stream of data. These subcarriers can be mathematically represented by utilizing a
complex form that is compatible with the usage of QAM. A transmitter and receiver combine up
the fundamental block diagram of OFDM system in Figure 2. At the transmitter side, the input bit
stream enters into the system. Normally, this input bit stream is de-multiplexed into smaller bit
streams that are given to each of the M-QAM modulators individually.
Figure 2. A basic OFDM system
The production of the time domain signal from the array of modulated subcarriers using the IFFT
is a crucial factor that facilitates the implementation of OFDM. The digital OFDM signal
obtained is subsequently applied to the DAC for conversion into an analogue waveform [30]. The
baseband signal is frequently subjected to up-conversion to a higher frequency prior to its
transmission across the channel. At the recipient, the process is reversed. The function of an
analogue down-converter (DN) is to perform a frequency shift on the OFDM signal, bringing it
back to the baseband. The ADC is responsible for converting the incoming signal into a digital
representation prior to transmitting it to the FFT block. The FFT module performs a conversion
of the input signal from the time domain to a collection of subcarriers in the frequency domain,
which are then modulated using QAM. Upon the completion of QAM demodulation, the bit
stream from each subcarrier is reproduced. Subsequently, the original single data stream is
5. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
25
reconstructed by the process of multiplexing [31]. Figure 3 illustrates the temporal and spectral
representation of an OFDM transmission signal.
Figure 3. combined view of the OFDM signal in the time and frequency domains
Figure 3 illustrates the time plus frequency domain visualization of an OFDM signal. A set of
OFDM subcarriers is represented by each symbol in the diagram and is transmitted along the
channel. Through the application of a digital modulation technique, the initial binary sequence
undergoes a conversion process resulting in a limited number of constellation points. The
utilization of a serial to parallel (S/P) converter is employed in order to divide the baseband
modulated symbols that have been successfully acquired into M-frames of identical length prior
to performing an IFFT operation. The generation of the baseband OFDM signal involves the
transmission of a sequence of baseband modulated symbols Sk via an IFFT block [32,35]. The
discrete-time transmitted OFDM signal, consisting of M subcarriers, can be represented by n
samples, given below:
2
1
0
1
;0 1
j kn
M
M
n k
k
s S e n M
M
(3)
The PAPR of the signals is the ratio of maximum power to average power and is generally
expressed as:
2
2
n
n
Max s
PAPR
E s
(4)
2
10 2
10log n
dB
n
Max s
PAPR
E s
(5)
The efficiency of the PAPR minimization method is often examined using the complementary
cumulative distribution function(CCDF). The CCDF may be defined as: "The probability that an
OFDM signal's PAPR will exceed a threshold level. ρ"
6. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
26
( ) 1 1
M
CCDF P PAPR e
(6)
3. PTS AND PSO-PTS METHOD
In the PTS approach, the input sequence is partitioned into many subsequences. Subsequently,
every subsequence of symbols undergoes an IFFT, and the resultant subsequences of signals are
combined by multiplication with a set of distinct rotating vectors [11]. The signal sequence
exhibiting the minimum PAPR is thereafter sent after evaluating the PAPR for each resulting
sequence. When the number of subcarriers and the sequence of modulation increase, prioritizing
the reduction of computational complexity is more important than minimizing redundancy.
The input data block, consisting of M symbols, is divided into N distinct sub-blocks using the
PTS technique. The IFFT is subsequently performed on each sub-block individually and is
multiplied by the corresponding complex phase factor m
i
n
p e
. In order to mitigate the PAPR
of the aggregate signal originating from all sub-blocks, appropriate phase factors are used. Figure
4 is a schematic diagram of the OFDM transmitter that incorporates the PTS technique. The input
data stream, denoted as S, is partitioned into N distinct sub blocks, referred to as Sn. Each sub
block undergoes an IFFT operation, and its associated weighted phase factor, pn
, is appropriately
modified. The objective is to determine the set of phase factors pn
that minimizes the PAPR of the
composite time-domain signals.
1
N
n
n
n
s p s
(7)
1
IFFT
N
n
n
n
s p S
(8)
~
1
N
n
n
n
s p x
(9)
The phase factors are selected to reduce the PAPR, which is expressed as follows:
~ ~ ~
1
1 2
, ,...., argmin max
N
n
n
n
n p s
p p p
(10)
The time-domain signal with the associated minimal PAPR is represented by:
~
1
N
n
n
n
s p s
(11)
It needs to be noted that choosing the best phase factors needs a thorough search of all possible
combinations of phase factors, which increases computing complexity. In order to decrease the
complexity of the search, a certain set of elements are limited by phase factor pn
. The best set of
phase vectors should be found by searching 4N
sets of phase factors as the range of permitted
7. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
27
phase factors is p={±1, ±j}. With more sub-blocks, the search complexity is obviously
considerably more difficult.
Figure 4. PTS method of OFDM PAPR minimization
PSO is a stochastic optimization approach that relies on the movement and behaviour of swarms.
In PSO, the utilization of social interaction is employed as a means to tackle various challenges.
The proposed method employs a collection of particles, referred to as agents, which navigate
inside the search region with the objective of locating the most optimum solution. Every
individual inside the swarm actively seeks the positional coordinates within the solution space
that correspond to the most optimal solution they have generated thus far. The term commonly
referred to as a personal best is denoted as pbest. The PSO algorithm also considers the global
best (gbest) as a significant metric. The maximum value is determined by the particle next to it.
In the initialization phase of the PSO algorithm, a random velocity is assigned to each possible
solution within the population of randomized solutions. The transportation of potential solutions
occurs inside the issue space in the form of particles. Particles have been shown to be associated
with the most optimal result or highest degree of physical fitness seen thus far. Furthermore, the
fitness value is also kept. The designated nomenclature for this particular value is "pbest".
Another significant measure identified by the international iteration of the PSO algorithm is the
collective best value attained by each particle inside the population, together with its
corresponding location. The term used to refer to this number is often known as "gbest." The
aforementioned is the worldwide manifestation of PSO. During each iteration, the particle
modifies its velocity and moves closer to its personal best (pbest) and the global best (gbest)
positions. The technique being referred to is commonly referred to as the local variant of PSO. In
this approach, each individual particle in the swarm keeps note of the best solution it has seen,
known as the neighbourhood best (nbest) or local best (lbest). This is achieved by considering a
small topological neighbourhood of particles [33]. One of the strategies employed in evolutionary
computing is the PSO algorithm. The primary objective was to demonstrate the stochastic
locomotion patterns of a collective of avian organisms. An enhanced PSO algorithm is proposed
in this study to minimize the high PAPR of an OFDM system using the PTS technique [34],
while reducing computational complexity. A collection of factors can be seen as a specific point
or place inside the extensive space of phase factors, where each value along a dimension
corresponds to a distinct component. The suggested PSO technique use a primary set of solutions
referred to as "particles" as the first starting point. Each particle is located at a specific position
inside the N-dimensional space. To clarify, it may be said that every particle possesses an N-
dimensional phase vector, whereby each component is selected from a set of phase factors.
Particles traverse across space in search of the most favorable location, and their final positions
are determined by the interplay of their interactions. Consequently, individuals seek out
opportunities for optimization at both local and global levels. Ultimately, each individual particle
8. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
28
achieves motion towards the optimal location. Particles possess the inherent potential to explore
and, as a result, they engage in a search process to identify the most favorable sequence of phase
factors.
Let Lj = (lj1, lj2,..., ljN) is the location/vector of the jth
particle, Pj = (pj1, pj2,..., pjN) is the best place
(pbest) found by the jth
particle and the best place discovered by all particles with the gbest index is
shown. Vj =(ϑj1,ϑj2,..,ϑjN) is used to denote the jth
particle's velocity (V). By using Eq.(12) and
(13), particles move.
1 2
( 1) ( )
jb jb
k k Q Q
(12)
Here , 1 1 1 ( ) ( ) ( )
b jb jb
Q a r k p k l k
, and 2 2 2 ( ) ( ) ( )
b jb jb
Q a r k p k l k
( 1) ( ) ( 1)
jb jb jb
l k l k k
(13)
Here, k indicates the number of iterations and b = 1, 2,..., N; ω stands for the inertia weight,
which has a positive value in terms of a time-varying linear function. The right inertia weight
establishes a balance between local and global exploration, which speeds up the algorithm's
ability to locate the best response.
ω = Iteration Number/Max Iteration (14)
The coefficients, a1 and a2, show how quickly each particle approaches its respective individual
and global optimal places. When these accelerations are low, particles circle the target region
without attempting to approach it, and when they are strong, particles travel toward the target
area at fast speeds and may even pass through it. Two uniformly distributed random numbers in
the range (0,1) are r1 and r2, respectively. The maximum velocity(Vmax) sets a limit on the particle
velocities. The greatest movement a particle can make in the search space is determined by this
vector. The particles cannot be investigated outside of the semi-optimal regions if the Vmax is low.
Particles may go through the optimal solution if Vmax is high. The difference in particle positions
at the two points determines the velocity. The new particle velocity is determined by applying Eq.
(12). The prior velocity is used to calculate the new velocity. The separation between the
particle's actual location and best location and the best location can be determined by the group.
The particle travels to the new position in accordance with Eq. (13) after computing its velocity.
The fitness of particles has been evaluated using the following evaluation:
1
( )
( )
fitness s
PAPR s
(15)
Algorithm
Initialize all parameters;
a1, a2, Max. iteration, p, particles, r1, r2, Vmax, ω
Initialize particles with random positions in the space
Let k=1
While(k ≤ Max. iteration)
k=k+1
For each particle do
Compute the position of the particle using ω
9. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
29
Update pbest of the particle
End
Select the best position find by all particles as a gbest for swarm
For each particle do
Evaluate the velocity of the particle using Vjb(k+1)
Update position of the particle using ljb(k+1)
End
End While
Return the phase factor set with lower PAPR as the solution.
Figure 5. Flowchart : PSO-PTS process
4. RESULTS
Various simulations have been performed to analyze the effectiveness of the PSO-PTS algorithm
for PAPR minimization in OFDM. MATLAB R2018a software was used to perform simulations.
Table 1. Simulation parameters
Parameters Value
No. of subcarriers 512
No. of symbols 1e4
Modulation QPSK
No. of sub-blocks 2,4,8,16
Over sample rate 4
Partition adjacency partition
No. of particles per generation 10
Iteration numbers [1 4 8 10 20 30]
Max iteration number 30
Learning factors a1 = 2; a2 = 2
Max velocity Vmax = 0.2
Length of weighting factor set 1,2,3
Min inertia weight vector wmin = 0.4
Max inertia weight vector wmax = 0.9
10. International Journal on AdHoc Networking Systems (IJANS) Vol. 13, No. 4, October 2023
30
Threshold value 6.7
Channel AWGN
The CCDF of the PAPR analysis for OFDM and PTS-based OFDM signals with different
numbers of sub-blocks is shown in Figure 6. From figure 6; at CCDF=10-4
, the PAPR of the
system without PTS is 11.9dB, for N=2 the PAPR is 11.2dB, for N=4 the PAPR is 10.2dB, for
N=8 the PAPR is 8.8dB and for N=16 the PAPR is 8.12dB. From figure, we can notice that, as
the no. of sub-blocks increases the PAPR of the system reduces. The PAPR comparison with
various phase factors is represented in figure 7. The phase weighting factor can be selected from
a greater range of 2,4, and 8. It is demonstrated that the greater degree of flexibility in selecting
the weighting factors for the combining phase results in an additional minimization. The PAPR
reduction performance is improved as the number of phase weighting factors increases. However,
due of the many iterations, the processing time increases.
Figure 6. PAPR comparison with various sub-blocks
Figure 7. PAPR comparison with various phase factors
Figure 8 shows some simulated results from the CCDF of the PAPR analysis for the OFDM
system with different iterations. The CCDF of the PAPR has improved as the number of
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generations has increased. When K is more than 40 however, the degree of improvement is
constrained. With K, the computational complexity increases. K increases lead to an
improvement in PAPR performance.
Figure 8. PAPR comparison with various iteration factors
Figure 9a. PAPR comparison: without PTS, IPTS, PSO-threshold and PSO
The suggested PSO for the PTS approach is shown in Figure 9 along with the CCDF comparison
of IPTS and PSO. At CCDF=10-3
, the PAPR of OFDM without PTS is 11.62dB, for IPTS and
proposed method, the PAPR values are 8.7 dB, and 8.25dB respectively. From figure, PSO
performs better in terms of PAPR minimization. With a threshold value, the PSO-PTS approach
shows less complexity. The PSO-PTS with threshold method is less difficult than the OPTS IPTS
method.
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Figure 9b. PAPR comparison: without PTS, IPTS, OPTS, PSO-threshold and PSO
Figure 10. BER Performance
Figure 10 shows a comparison of the BER effectiveness of the PSO-PTS approach to other
methods. The SNR for the original signal is 9dB at a CCDF of 10-3
. The SNR is 7.3db, 6.8dB and
6.2dB for IPTS, PSO and PSO-PTS, respectively. When the PSO-PTS approach is applied, the
BER performance improves. Figure 11 shows the spectral efficiency(SE) of the OFDM system
with various methods. When SNR=20dB, the SE values are 0.7, 1, 1.4 and 2 for original signal,
IPTS, PSO and PSO-PTS. The PSO-PTS provides higher spectral efficiency.
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Figure 11. Spectral efficiency
5. CONCLUSION
The PAPR reduction performance of the PTS approach was examined in this article. An
exhaustive search was used to simulate the PTS's phase rotation factors search. An adaptive PSO
was presented to identify the optimal phase rotation parameters with less complexity in order to
minimize the complexity of the exhaustive search. In this article, a PSO algorithm is used to find
the optimal phase factors for the PTS approach to minimize PAPR more quickly. Experimental
analysis show that the suggested approach works better than previous evolutionary computation
techniques by reducing the PAPR when compared to other methods. The suggested method is
efficient since it offers a good PAPR reduction, higher spectral efficiency, better BER
performance and low computing complexity.
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AUTHORS
Karthik Kumar Vaigandla, obtained B.Tech in Electronics and Communication Engineering from
Jayamukhi Institute of Technological Sciences, Warangal, Telangana, India in 2008 and M.Tech in
Embedded systems from Ramappa Engineering College, Warangal, Telangana, India in 2011. Currently
working as a Assistant Professor in Electronics and Communication Engineering from Balaji Institute of
Technology and Science, Telangana, India. Total Teaching experience of 15 years and 4 years research
experience. He has the credit of having published 10 research papers in Web of Science/Scopus Indexed
journals, 30 papers in UGC CARE listed/refereed/reviewed journals and 10 papers presented in
international conferences. Current research interest includes on wireless communications, Communication
networks, and signal processing. He is the Life Member of Indian Society for Technical Education (ISTE),
Teaching and Education Research Association (TERA), International Association of Engineers(IAENG)
and Middle East Association of Computer Science and Engineering(MEACSE).
Dr.Madhu Kumar Vanteru, currently working as an Associate Professor in Balaji Institute of
Technology and Science (An Autonomous institute, Accredited by NBA and NAAC A+), Narsampet,
Warangal, Telangana. He has completed Masters in DSCE from JNTU Hyderabad. He completed his Ph.D
from GITAM University, Visakhapatnam, Andhra Pradesh. He is the Member of IEEE, IE and Life
Member of ISTE. He is having 16 years of experience in teaching. His research areas are Signal Processing
and Wireless Communications. His research papers are published in several National and International
Publications.
Mr. Prasad Dudimetla, Assistant Professor, Balaji Institute of Technology and Science (An Autonomous
institute, Accredited by NBA and NAAC A+), Narsampet, Warangal, Telangana. He has completed
Masters in DSCE from JNTU Hyderabad. He pursuing his Ph.D from SSSUTMS University, Bophal,
Madhya Pradesh. He is having 13 years of experience. His research area is VLSI Design. His research
papers are published in several National and International Publications.