Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication
and wireless communication systems as it provides enhanced spectral efficiency than Frequency division
multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to
average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reduction
techniques have been used, including techniques based on companding. Incompanding, -Law
companding has potential to reduce the PAPR of OFDMsignals. -Law Companding technique
preserves the dynamic range of samples at low amplitudes.A new method named as precoding which is
having less complexity compared to the other power reduction techniques is proposed to reduce PAPR.
This paper put forward combination of two existing techniques namely -Law Companding Transform
and Discrete Cosine Transform-II precoding technique. The simulation results show that, the proposed
combinedscheme gives better result for PAPR Reduction and results in no distortion.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
What is the purpose of 5G flexible duplexing?
The purpose of 5G flexible duplexing is to allow the most flexible use of an operator's spectrum for time-frequency resources in a single framework. 5G Flexible duplexing should inherently support both paired and unpaired spectrum and be forward compatible with full-duplex 5G.
INTERFERENCE TOLERANT MULTIUSER OFDMA FOR FEMTO CELLSijwmn
An interference tolerant OFDMA scheme is proposed for multiuser wireless communications with specific application in femto cells. An interleaved set of subcarriers is dedicated to each user to provide with a high order of frequency diversity. A reduced complexity digital implementation of the technique is proposed and discussed for the interleaved sub-carrier arrangement. Both inter-symbol interference and other-user interference are mitigated using a proper cyclic extension, provided that the relative propagation delays of the users are an integer multiple of a symbol period. The effect of other-user interference due to non-integer propagation delays is investigated using computer simulations. The bit error rate performance and signal to interference ratio are presented for a few example systems over both an Additive White Gaussian Noise (AWGN) and a frequency selective Rayleigh fading channel. The amount of other-user interference is shown to be reduced as the number of sub-carriers per user is increased. The effect of design parameters on the interference level is discussed.
In recent past the influence of Radar has played a significant part in various fields. Radar sensing is one of
the prime application by which velocity and distance of a moving target can be found out. A joint RadCom
system to serve both radar sensing and wireless communication is proposed which ensures better
performance in terms of spectral efficiency, extended detection range and cost effectiveness. Such systems
demand for a common waveform which is designed in this work that perfectly matches to the system
requirements. OFDM multi carrier technique is chosen to generate a common waveform. Applicability of
multiple antenna technique for direction of arrival estimation is also considered. MIMO-OFDM technique
has gained much interest in the field of communication which improves the signal to noise ratio and lowers
the bit error rate. On the other hand the usage of MIMO reflects in the form of interference between
signals. In order to overcome this effect beamforming technique is used. In addition to theoretical
explanations we have also simulated and discussed the results for the proposed RadCom system using
MATLAB simulation tool.
Performance analysis of multilayer multicast MANET CRN based on steiner minim...TELKOMNIKA JOURNAL
In this study, the multicast mobile ad hoc (MANET) CRN has been developed, which involves multi-hop and multilayer consideration and Steiner minimal tree (SMT) algorithm is employed as the router protocol. To enhance the network performance with regards to throughput and packet delivery rate (PDR), as channel assignment scheme, the probability of success (POS) is employed that accounts for the channel availability and the time needed for transmission when selecting the best channel from the numerous available channels for data transmission from the source to all destinations nodes effectively. Within Rayleigh fading channels under various network parameters, a comparison is done for the performance of SMT multicast (MANET) CRN with POS scheme versus maximum data rate (MDR), maximum average spectrum availability (MASA) and random channel assignment schemes. Based on the simulation results, the SMT multicast (MANET) CRN with POS scheme was seen to demonstrate the best performance versus other schemes. Also, the results proved that the throughput and PDR performance are improved as the number the primary channels and the channel’s bandwidth increased while dropped as the value of packet size D increased. The network’s performance grew with rise in the value of idle probability (푃퐼) since the primary user’s (PU) traffic load is low when the value of 푃퐼 is high.
Successful interference cancellation with Blind Equalization method for MC-CD...IJTET Journal
Abstract— The increasing demand for wireless services has created the need for cost effective transmission techniques that can exploit scarce spectral resources efficiently. Inorder to achieve the high data rates needed to meet the quality of service requirements of future multimedia applications, MC-CDMA has been considered as good air-interface candidate, especially for the downlink. However, the user capacity of MC-CDMA system is essentially limited by interference. This interference can be mitigated by employing precoding techniques, IB-DFE based receivers and other efficient interference suppression techniques. In the proposed system, combined Iterative IA precoding at the transmitter with IB-DFE based processing at the receiver is suggested for MC-CDMA systems. The matrices for this nonlinear space-frequency equalizer are obtained by minimizing the overall MSE of all data streams at each subcarrier.
What is the purpose of 5G flexible duplexing?
The purpose of 5G flexible duplexing is to allow the most flexible use of an operator's spectrum for time-frequency resources in a single framework. 5G Flexible duplexing should inherently support both paired and unpaired spectrum and be forward compatible with full-duplex 5G.
INTERFERENCE TOLERANT MULTIUSER OFDMA FOR FEMTO CELLSijwmn
An interference tolerant OFDMA scheme is proposed for multiuser wireless communications with specific application in femto cells. An interleaved set of subcarriers is dedicated to each user to provide with a high order of frequency diversity. A reduced complexity digital implementation of the technique is proposed and discussed for the interleaved sub-carrier arrangement. Both inter-symbol interference and other-user interference are mitigated using a proper cyclic extension, provided that the relative propagation delays of the users are an integer multiple of a symbol period. The effect of other-user interference due to non-integer propagation delays is investigated using computer simulations. The bit error rate performance and signal to interference ratio are presented for a few example systems over both an Additive White Gaussian Noise (AWGN) and a frequency selective Rayleigh fading channel. The amount of other-user interference is shown to be reduced as the number of sub-carriers per user is increased. The effect of design parameters on the interference level is discussed.
In recent past the influence of Radar has played a significant part in various fields. Radar sensing is one of
the prime application by which velocity and distance of a moving target can be found out. A joint RadCom
system to serve both radar sensing and wireless communication is proposed which ensures better
performance in terms of spectral efficiency, extended detection range and cost effectiveness. Such systems
demand for a common waveform which is designed in this work that perfectly matches to the system
requirements. OFDM multi carrier technique is chosen to generate a common waveform. Applicability of
multiple antenna technique for direction of arrival estimation is also considered. MIMO-OFDM technique
has gained much interest in the field of communication which improves the signal to noise ratio and lowers
the bit error rate. On the other hand the usage of MIMO reflects in the form of interference between
signals. In order to overcome this effect beamforming technique is used. In addition to theoretical
explanations we have also simulated and discussed the results for the proposed RadCom system using
MATLAB simulation tool.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Wavelet Packet based Multicarrier Modulation for Cognitive UWB SystemsCSCJournals
Orthogonal frequency division multiplexing (OFDM) is a multi-carrier modulation (MCM) scheme where the sub carriers are orthogonal waves. The main advantages of OFDM are robustness against multi-path fading, frequency selective fading, narrowband interference, and efficient use of spectrum. Recently it is proved that MCM system optimization can be achieved by applying wavelet bases instead of conventional fourier bases. Wavelet packet based MCM (WPMCM) systems have overall the same capabilities as OFDM systems with some improved features. In this research the literature and analytic schemes of WPMCM system is addressed, a wavelet packet based cognitive ultra wideband (UWB) transceiver is proposed, and performance analysis of WPMCM in different wireless multipath channels is investigated. Simulation results show a significant enhancement in terms of BER, spectral efficiency and side-lobes suppression comparing to conventional OFDM.
Mitigation of non-linear four-wave mixing phenomenon in a fully optical commu...TELKOMNIKA JOURNAL
This paper aims to point out the nonlinear phenomenon occurring in coarse/dense wavelength division multiplex (C/D-WDM) systems. This phenomenon has to betaken into account during the design of the optical network itself, as wavelengthsin the optical fiber are constantly densified. The paper points out the emergence of the non-linear four-wave mixing (FWM) phenomenonand how it relates to the dispersion in the optical fiber together with the transmit power. The output of the paper is a proposed design of the system that points to the improvement of the bit error rate (BER) with a suitable choice of dispersion and suitable transmission power.
Abstract: The growing demand on wireless communication service has created the necessity to support higher data rates for multimedia services. .As next generation wireless communication networks are expected to provide broadband multimedia services such as voice, web browsing, video conferencing etc. For high data rate achievement one must enhance the capacity of the wireless communication system. The capacity of a communication system can be enhanced by using OFDM system. OFDM is commonly used for communication system due to its high transmission rate and robustness against multipath fading So as to enhance the capacity of fading channels the OFDM system are combined to form hybrid system. Capacity is the measure of maximum information that can be transmitted reliably over a channel. This paper review on different channel capacity enhancement techniques used in OFDM system is SVD (Singular Value Decomposition), water Filling algorithm.
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]
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
IMPLEMENTATION OF LINEAR DETECTION TECHNIQUES TO OVERCOME CHANNEL EFFECTS IN ...IJCI JOURNAL
Spatial diversity technique enables improvement in quality and reliability of wireless link. Antenna
diversity along with understanding effects of channel on transmitted signal and methods to overcome the
channel impairment plays an important role in wireless communication where sharing of channel occurs
between users. In this paper single input single output system (SISO) is compared with multiple input
multiple output system (MIMO) in terms of bit error rate performance. Bit error rate performance is also
evaluated for MIMO with least squares (LS) and Minimum mean square error (MMSE) linear detection.
Further analysis and simulation is done to understand the effect of channel imperfections on BER.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
Channel characterization and modulation schemes of ultra wideband systemsijmnct
Channel measurements are generally the basis for channel models. Strictly speaking, channel models do
not exclusively require measurements, but it is a fact that all standardized models are derived from
measurements. This licentiate paper is focused on the characterization of ultra-wideband wireless channels.
The paper presents the characterization of ultra wide band system with their benefits and drawbacks within
the telecommunication industry. Furthermore with the advantages of Ultra wideband several modulation
techniques for UWB are discussed in this paper.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Wavelet Packet based Multicarrier Modulation for Cognitive UWB SystemsCSCJournals
Orthogonal frequency division multiplexing (OFDM) is a multi-carrier modulation (MCM) scheme where the sub carriers are orthogonal waves. The main advantages of OFDM are robustness against multi-path fading, frequency selective fading, narrowband interference, and efficient use of spectrum. Recently it is proved that MCM system optimization can be achieved by applying wavelet bases instead of conventional fourier bases. Wavelet packet based MCM (WPMCM) systems have overall the same capabilities as OFDM systems with some improved features. In this research the literature and analytic schemes of WPMCM system is addressed, a wavelet packet based cognitive ultra wideband (UWB) transceiver is proposed, and performance analysis of WPMCM in different wireless multipath channels is investigated. Simulation results show a significant enhancement in terms of BER, spectral efficiency and side-lobes suppression comparing to conventional OFDM.
Mitigation of non-linear four-wave mixing phenomenon in a fully optical commu...TELKOMNIKA JOURNAL
This paper aims to point out the nonlinear phenomenon occurring in coarse/dense wavelength division multiplex (C/D-WDM) systems. This phenomenon has to betaken into account during the design of the optical network itself, as wavelengthsin the optical fiber are constantly densified. The paper points out the emergence of the non-linear four-wave mixing (FWM) phenomenonand how it relates to the dispersion in the optical fiber together with the transmit power. The output of the paper is a proposed design of the system that points to the improvement of the bit error rate (BER) with a suitable choice of dispersion and suitable transmission power.
Abstract: The growing demand on wireless communication service has created the necessity to support higher data rates for multimedia services. .As next generation wireless communication networks are expected to provide broadband multimedia services such as voice, web browsing, video conferencing etc. For high data rate achievement one must enhance the capacity of the wireless communication system. The capacity of a communication system can be enhanced by using OFDM system. OFDM is commonly used for communication system due to its high transmission rate and robustness against multipath fading So as to enhance the capacity of fading channels the OFDM system are combined to form hybrid system. Capacity is the measure of maximum information that can be transmitted reliably over a channel. This paper review on different channel capacity enhancement techniques used in OFDM system is SVD (Singular Value Decomposition), water Filling algorithm.
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]
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
IMPLEMENTATION OF LINEAR DETECTION TECHNIQUES TO OVERCOME CHANNEL EFFECTS IN ...IJCI JOURNAL
Spatial diversity technique enables improvement in quality and reliability of wireless link. Antenna
diversity along with understanding effects of channel on transmitted signal and methods to overcome the
channel impairment plays an important role in wireless communication where sharing of channel occurs
between users. In this paper single input single output system (SISO) is compared with multiple input
multiple output system (MIMO) in terms of bit error rate performance. Bit error rate performance is also
evaluated for MIMO with least squares (LS) and Minimum mean square error (MMSE) linear detection.
Further analysis and simulation is done to understand the effect of channel imperfections on BER.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
Channel characterization and modulation schemes of ultra wideband systemsijmnct
Channel measurements are generally the basis for channel models. Strictly speaking, channel models do
not exclusively require measurements, but it is a fact that all standardized models are derived from
measurements. This licentiate paper is focused on the characterization of ultra-wideband wireless channels.
The paper presents the characterization of ultra wide band system with their benefits and drawbacks within
the telecommunication industry. Furthermore with the advantages of Ultra wideband several modulation
techniques for UWB are discussed in this paper.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Abstract: Mobile Communication system has been on high rampage for high data transmission over wireless medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years to deal with this problems because of its ability to elegantly cope with multipath interference. This paper investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping. Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM allows data transmission with minimal error over fading channel than a Single Carrier. Keywords: OFDM, Single Carrier, AWGN, Rayleigh fading, BER, M-ary PSK, M-ary QAM
Channel Estimation Techniques in MIMO-OFDM LTE SystemsCauses and Effects of C...IJERA Editor
There is an increasing demand for high data transmission rates with the evolution of the very large scale integration (VLSI) technology. The multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems are used to fulfill these requirements because of their unique properties such as high spectral efficiency, high data rate and resistance towards multipath propagation. MIMO-OFDM systems are finding their applications in the modern wireless communication systems like IEEE 802.11n, 4G and LTE. They also offer reliable communication with the increased coverage area. The bottleneck to the MIMO-OFDM systems is the estimation of the channel state information (CSI). This can be estimated with the help of any one of the Training Based, Semiblind and Blind Channel estimation algorithms. This paper presents various channel estimation algorithms, optimization techniques and their effective utilization in MIMO-OFDM for modern wireless LTE systems.
Improving The Performance Of Multiuser OFDM Wireless System With UWB ChannelIJTET Journal
The multi user OFDM system can be used to produce a highly flexible and effective communication
system. In the existing multi user OFDM system, resource allocation to each user is the major problem. Also the existing
multi user OFDM system uses frequency diversity technique that requires sparse bandwidth and multiple receivers
improving the complexity. In order to increase the system performance, the proposed system allows multiple user data to
be multiplexed together to form a single OFDM symbol where the resources are allocated equally to all users. The
proposed multiuser OFDM system achieves double the capacity and better performance in terms of Signal-to-Noise Ratio
and Bit Error Rate of a single user OFDM system and the UWB channel is used to securely transmit the data through the
channel. Also, the proposed system reduces the receiver complexity by using polarization diversity to receive the
multipath components for multiple users.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Orthogonal frequency-division multiplexing (OFDM)
[1] is a method of encoding digital data on multiple carrier
frequencies. OFDM[1] has developed into a popular scheme
for wideband digital communication, whether wireless or
over copper wires, used in applications such as digital television
and audio broadcasting, DSL Internet access, wireless networks,
powerline networks, and 4G mobile communications. In the
Several wireless standards such as IEEE 802.11a[2] and
HiperLAN2[3].The orthogonality of the subcarriers is no longer
maintained which results in ICI (Inter carrier Interference)[4]
.ICI reduction techniques achieve a better SNR and BER in
OFDM at zero phase noise variance . This technique will use a
large number of closely spaced orthogonal subcarriers to avoid
phase noise. It provides high data rates with sufficient robustness
to radio channel damages. A major problem in OFDM is carrier
frequency offset error between the transmitted and received
signals. Due to this the orthogonality of the subcarriers is no
longer maintained which results in ICI (Inter carrier
Interference). In this paper, we used the ICI self-cancellation
technique and reduced the ICI and improved the BER and SNR
we are also calculate the SNR=15db and 20db at different phase
noise variance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
One of vital parts of the mobile wireless channel is channel estimation significantly
improve the performance of the system, especially for 4G LTE and 5G systems. The
main goal of this project is to test the time-variant channel estimation using F-OFDM
model. It investigates the Mean Square Error (MSE), the Least Squares (LS) method
and compares performance of OFDM and F-OFDM using BER vs SNR.
PAPR REDUCTION AND BIT ERROR RATE EVALUATION IN OFDM SYSTEM USING HYBRID TECH...pijans
Orthogonal frequency division multiplexing (OFDM) has become an important component of waveform
generation in wideband transmission. it's a superior technology for the high-speed rate of wired and
wireless communication systems. Currently, multiple-input multiple-output orthogonal frequency division
multiplexing (MIMO OFDM) systems are crucial wireless communication systems like 4G and 5G
networks & tactical communication. The OFDM has many advantages over other techniques like its high
capacity and immunity against multipath fading channels. However, one amongst the foremost drawbacks
of the OFDM system is that the high-peak-to-average power ratio (PAPR) that leads the system to provide
in-band distortion and out-of-band radiation and reduces its efficiency. This problem increases with a rise
within the number of transmit antennas. Therefore, it's highly desirable to cut back the PAPR of an OFDM
signal. For this, numerous techniques are proposed to beat the PAPR problem like i) Selective mapping
(SLM) ii) Partial transmit sequence (PTS), iii) Clipping, iv) Clipping and filtering. All of those are reduced
the PAPR by generating alternative subcarrier vector that are statistically independent OFDM symbols for
a given data frame and transmitting the symbol with rock bottom peak power. During this paper we also
proposed, some hybrid techniques. The hybrid techniques are the technique of clipping is employed in
conjunction with SLM and PTS to cut back computational complexity. And also the combination of SLM-
PTS to scale back PAPR. Simulations are acquainted with analyze the efficiency of the techniques used
which signifies OFDM to be providing much better PAPR reduction and a way better Bit Error Rate
(BER). it's shown in simulation results that the proposed scheme performs well reducing PAPR. But the
proposed scheme is more complex than the prevailing techniques.
PAPR REDUCTION AND BIT ERROR RATE EVALUATION IN OFDM SYSTEM USING HYBRID TECH...pijans
Orthogonal frequency division multiplexing (OFDM) has become an important component of waveform
generation in wideband transmission. it's a superior technology for the high-speed rate of wired and
wireless communication systems. Currently, multiple-input multiple-output orthogonal frequency division
multiplexing (MIMO OFDM) systems are crucial wireless communication systems like 4G and 5G
networks & tactical communication. The OFDM has many advantages over other techniques like its high
capacity and immunity against multipath fading channels. However, one amongst the foremost drawbacks
of the OFDM system is that the high-peak-to-average power ratio (PAPR) that leads the system to provide
in-band distortion and out-of-band radiation and reduces its efficiency. This problem increases with a rise
within the number of transmit antennas. Therefore, it's highly desirable to cut back the PAPR of an OFDM
signal. For this, numerous techniques are proposed to beat the PAPR problem like i) Selective mapping
(SLM) ii) Partial transmit sequence (PTS), iii) Clipping, iv) Clipping and filtering. All of those are reduced
the PAPR by generating alternative subcarrier vector that are statistically independent OFDM symbols for
a given data frame and transmitting the symbol with rock bottom peak power. During this paper we also
proposed, some hybrid techniques. The hybrid techniques are the technique of clipping is employed in
conjunction with SLM and PTS to cut back computational complexity. And also the combination of SLMPTS to scale back PAPR. Simulations are acquainted with analyze the efficiency of the techniques used
which signifies OFDM to be providing much better PAPR reduction and a way better Bit Error Rate
(BER). it's shown in simulation results that the proposed scheme performs well reducing PAPR. But the
proposed scheme is more complex than the prevailing techniques.
Survey on PAPR Reduction Techniques in OFDM Systemijtsrd
Orthogonal frequency division multiplexing OFDM is perhaps the most spectrally efficient, robust transmission technique discovered so far for communication systems, and it also mitigates the problem of multipath environment. Due to its advantages in multipath fading channel e.g. robust against ISI, ICI and some other advantages like best QoS for multiple users, efficient usage of bandwidth it is suggested to be the modulation technique for next generation 4G networks e.g. LTE. But along with all its advantages there are some disadvantages also e.g. High PAPR Peak to Average Power Ratio at the transmitter end and BER Bit Error Rate at the receiving end. OFDM is used in the downlink of 4G networks. To reduce the problems of OFDM some techniques e.g. SLM, PTS, Clipping, Coding, and Pre coding etc are suggested but none of them is reduce the PAPR and BER to an acceptable value. This Paper will discuss some techniques of PAPR and BER reduction, and their advantages and disadvantages in detail. Vikas Kumar | Preeti Sondhi "Survey on PAPR Reduction Techniques in OFDM System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26817.pdf Paper URL: https://www.ijtsrd.com/engineering/other/26817/survey-on-papr-reduction-techniques-in-ofdm-system/vikas-kumar
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
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/
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
DISCRETE COSINETRANSFORM-II FOR REDUCTION IN PEAK TO AVERAGE POWER RATIO OF OFDM SIGNALS THROUGH -LAW COMPANDING TECHNIQUE
1. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
DOI : 10.5121/ijwmn.2013.5211 143
DISCRETE COSINETRANSFORM-II FOR
REDUCTION IN PEAK TO AVERAGE POWER RATIO
OF OFDM SIGNALS THROUGH -LAW
COMPANDING TECHNIQUE
NavneetKaur and Lavish Kansal
Department of Electronics and Communication Engineering
Lovely Professional University, Phagwara
Punjab, India
nv_neet@yahoo.com
Department of Electronics and Communication Engineering
Lovely Professional University, Phagwara
Punjab, India
lavish.15911@lpu.co.in
Abstract
Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication
and wireless communication systems as it provides enhanced spectral efficiency than Frequency division
multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to
average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reduction
techniques have been used, including techniques based on companding. Incompanding, -Law
companding has potential to reduce the PAPR of OFDMsignals. -Law Companding technique
preserves the dynamic range of samples at low amplitudes.A new method named as precoding which is
having less complexity compared to the other power reduction techniques is proposed to reduce PAPR.
This paper put forward combination of two existing techniques namely -Law Companding Transform
and Discrete Cosine Transform-II precoding technique. The simulation results show that, the proposed
combinedscheme gives better result for PAPR Reduction and results in no distortion.
Keywords
FDM, FDM, PAPR, FFT, IEEE, DCT, CCDF
1. INTRODUCTION
As the demand for high data rate wireless digital communication is rapidly expanding, several
approaches such as increasing modulation order or employing multiple antennas at both
transmitter and receiver that are reliable for wireless systems have been studied to enhance the
spectral efficiency [1,2]. In today’s communication systems Orthogonal Frequency Division
Multiplexing (OFDM), widespread modulation technique has been considered to achieve high
rate data transmission for wireless environment.OFDM system has high spectral efficiency,
ease of implementation using the fast Fourier transform (FFT) and simple equalization
techniques and also provides immunity to multipath fading, robustness against inter-symbol
2. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
144
interference. Therefore it is considered for digital communication systems and also for future
broadband applications.
Multicarrier networks such as Frequency Division Multiplexing (FDM) have been around since
the late 1950’s [3], however due to their implementation complexity transmitted in parallel.
Multicarrier systems in wireless applications are less susceptible to channel induced distortions
than single carrier systems at corresponding data rates and inefficient use of the frequency band
they were restricted to military applications.
In multicarrier transmission, a single data stream bearing a large number of narrow-band
subcarriers is transmitted over a number of lower rate subcarriers.Thesesubcarriers are regularly
spaced in frequency, domain to avoid the interference. The subcarriers are totally independent
of each other because thefrequency spacing and time synchronization of the subcarriers is
chosen in such a waythat the subcarriers are orthogonal. By selecting a special set of orthogonal
carrier frequencies, high spectral efficiency isobtained because the spectra of the sub-carriers do
not overlap. The orthogonality among subcarriers can be maintained by introducing a cyclic
prefix over a dispersive channel. The advantage of this structure over single carrier systems is
that the extended symbol time due to lower data rate makes the signal less susceptible to effects
of the channel such as multipath propagation which introduces Inter Symbol Interference (ISI).
Each sub-channel will therefore experience flat fading reducing the equalization complexity in
the receiver.
Fig. 1: Block Diagram of OFDM system
In an OFDM scheme shown in fig. 1, the orthogonal and overlapped subcarriers are a large
number of orthogonal, overlapping, narrow band sub-carriers are transmitted in
parallel.Maintaining total data rates similar to conventional single-carrier modulation schemes
in the same bandwidth to modulate each sub-carrier is with a conventional modulation scheme
such as Quadrature Amplitude Modulation (QAM) or Phase-Shift Keying (PSK) at a low
symbol rate than that required for the whole data stream, but still.In OFDM system a high speed
data is splits into a number of parallel lower data rate streams and these low rates data streams
are transmitted simultaneously over a number of orthogonal subcarriers.The amount of
dispersion in time caused due to multipath delay is reduced as, the symbol duration increases
for lower rate parallel sub-carriers. These carriers divide the available transmission bandwidth.
International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
144
interference. Therefore it is considered for digital communication systems and also for future
broadband applications.
Multicarrier networks such as Frequency Division Multiplexing (FDM) have been around since
the late 1950’s [3], however due to their implementation complexity transmitted in parallel.
Multicarrier systems in wireless applications are less susceptible to channel induced distortions
than single carrier systems at corresponding data rates and inefficient use of the frequency band
they were restricted to military applications.
In multicarrier transmission, a single data stream bearing a large number of narrow-band
subcarriers is transmitted over a number of lower rate subcarriers.Thesesubcarriers are regularly
spaced in frequency, domain to avoid the interference. The subcarriers are totally independent
of each other because thefrequency spacing and time synchronization of the subcarriers is
chosen in such a waythat the subcarriers are orthogonal. By selecting a special set of orthogonal
carrier frequencies, high spectral efficiency isobtained because the spectra of the sub-carriers do
not overlap. The orthogonality among subcarriers can be maintained by introducing a cyclic
prefix over a dispersive channel. The advantage of this structure over single carrier systems is
that the extended symbol time due to lower data rate makes the signal less susceptible to effects
of the channel such as multipath propagation which introduces Inter Symbol Interference (ISI).
Each sub-channel will therefore experience flat fading reducing the equalization complexity in
the receiver.
Fig. 1: Block Diagram of OFDM system
In an OFDM scheme shown in fig. 1, the orthogonal and overlapped subcarriers are a large
number of orthogonal, overlapping, narrow band sub-carriers are transmitted in
parallel.Maintaining total data rates similar to conventional single-carrier modulation schemes
in the same bandwidth to modulate each sub-carrier is with a conventional modulation scheme
such as Quadrature Amplitude Modulation (QAM) or Phase-Shift Keying (PSK) at a low
symbol rate than that required for the whole data stream, but still.In OFDM system a high speed
data is splits into a number of parallel lower data rate streams and these low rates data streams
are transmitted simultaneously over a number of orthogonal subcarriers.The amount of
dispersion in time caused due to multipath delay is reduced as, the symbol duration increases
for lower rate parallel sub-carriers. These carriers divide the available transmission bandwidth.
International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
144
interference. Therefore it is considered for digital communication systems and also for future
broadband applications.
Multicarrier networks such as Frequency Division Multiplexing (FDM) have been around since
the late 1950’s [3], however due to their implementation complexity transmitted in parallel.
Multicarrier systems in wireless applications are less susceptible to channel induced distortions
than single carrier systems at corresponding data rates and inefficient use of the frequency band
they were restricted to military applications.
In multicarrier transmission, a single data stream bearing a large number of narrow-band
subcarriers is transmitted over a number of lower rate subcarriers.Thesesubcarriers are regularly
spaced in frequency, domain to avoid the interference. The subcarriers are totally independent
of each other because thefrequency spacing and time synchronization of the subcarriers is
chosen in such a waythat the subcarriers are orthogonal. By selecting a special set of orthogonal
carrier frequencies, high spectral efficiency isobtained because the spectra of the sub-carriers do
not overlap. The orthogonality among subcarriers can be maintained by introducing a cyclic
prefix over a dispersive channel. The advantage of this structure over single carrier systems is
that the extended symbol time due to lower data rate makes the signal less susceptible to effects
of the channel such as multipath propagation which introduces Inter Symbol Interference (ISI).
Each sub-channel will therefore experience flat fading reducing the equalization complexity in
the receiver.
Fig. 1: Block Diagram of OFDM system
In an OFDM scheme shown in fig. 1, the orthogonal and overlapped subcarriers are a large
number of orthogonal, overlapping, narrow band sub-carriers are transmitted in
parallel.Maintaining total data rates similar to conventional single-carrier modulation schemes
in the same bandwidth to modulate each sub-carrier is with a conventional modulation scheme
such as Quadrature Amplitude Modulation (QAM) or Phase-Shift Keying (PSK) at a low
symbol rate than that required for the whole data stream, but still.In OFDM system a high speed
data is splits into a number of parallel lower data rate streams and these low rates data streams
are transmitted simultaneously over a number of orthogonal subcarriers.The amount of
dispersion in time caused due to multipath delay is reduced as, the symbol duration increases
for lower rate parallel sub-carriers. These carriers divide the available transmission bandwidth.
3. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
145
The sub-carriers are separated in such a way so that there is a very compact spectral utilization
and each being modulated at a low bit rate. In a conventional frequency division multiplex the
carriers are spaced apart to avoid spectral overlap and multipath distortion.
OFDM has progressed to the point where it has now been widely used for various
communication applications such as digital audio and video broadcasting, asymmetric digital
subscriber line modems, and wireless local area networks systems(WLAN).It has also been
adopted as the physical layer modulation scheme for wireless networking standards such as
Hiperlan2 in Europe and the Institute of Electrical and Electronic Engineers (IEEE) 802.11a, g
standards in the United States.
OFDM systems have a large dynamic signal range with a very high peak to average power ratio
(PAPR) which is a one of major drawbacks of the transmitted OFDM signal. As a result, the
OFDM signal will be clipped when passed through a nonlinear high power amplifier (HPA) at
the transmitter as it only operate in its linear region with sufficient back-off. Thus, HPA with a
large dynamic range is required for OFDM systems. These amplifiers are very expensive and
are major cost component of the OFDM systems. Thus reduction in the value of the PAPR not
only reduces the cost of OFDM systems and reduces the complexity of analog-to-digital (A/D)
and digital-to-analog (D/A) converters, but also increases the transmit power, thus, improving
received signal-noise-ratio (SNR).
To reduce the PAPR, several techniques have been proposed, which can be divided into three
groups.The first group of reduction techniques includes signal distortion techniques, which
reduce the peak amplitudes simply by nonlinearly distorting the OFDM signal at or around the
peaks. Examples of distortion techniques are clipping [5], peak windowing [6], and peak
cancellation. Second, there are coding techniques that use a special code set that excludes
OFDM symbols with a large PAPR. The special codes includes Golay complementary
sequence [7], Reed Muller code [8], and Hadamard code in this approach [9].The third
technique scrambles each OFDM symbol with different scrambling sequences and selecting the
sequence that gives the smallest PAPR such as selected mapping (SLM) [10] and partial
transmit sequence (PTS) [11].
The organization of this paper is as follow. Section 2 presents formulates the problem of PAPR
in OFDM system.The reduction technique based on µ-Law companding is explained in section
3.Section 4 describes the precoding based Discrete Cosine Transform-II technique. PAPR
schemes based on combined DCT-II and µ-Law companding technique are proposed in section
5. Computer simulations results are presented in Section 6. Section 6 draws conclusions
regarding the existing and proposed combined technique.
2. PAPR IN OFDM SIGNAL
Presence of large number of independently modulated sub-carriers in an OFDM system
increasesthe peak value of the system as compared to the average of the whole system. The
ratio of the peak to average power value is termed as Peak to Average Power Ratio.At some
instant in time coherent addition of independently modulated N sub-carriers same phase
produces a peak:
PAPR[ ( )]=
4. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
146
=10
| ( )|
[| | ]
(1)
Where represents peak output power, means average output power. E[ ·]
denotesthe expected value, represents the transmitted OFDM signals which are obtained by
takingIFFT operation on modulated input symbols is expressed as:
=
∑ (2)
WhereN is the total number of subcarriers and the OFDM symbol duration is T seconds.
An OFDM symbol consists of N subcarriers by the frequency spacing of ∆f. The total
bandwidthBof a symbol will be divided into N equally spaced subcarriers and thus, all the
subcarriers are orthogonal to each other within a time interval of length T=1 ∆⁄ . A complex
modulation symbol , , isused to modulate each sub-carrier independently where m is a time
index and n is a subcarrier index.Then within the time interval T the following signal of the m-
th OFDM block period can be described as:
( )=√
∑ , ( − ) (3)
Where, (t) is defined as:
(t)=
exp( 2 ∆ ) , 0 ≤ ≤
0,
(4)
Where, (t) is a rectangular pulse applied to each subcarrier. The total continuous time signal
x (t) consisting of all the OFDM block is given as:
( )=
√
∑ ∑ , ( ) (5)
When compared with traditional single carrier systems, the instantaneous output of an OFDM
system often has large fluctuations. To handle these large fluctuations the system devices, such
as power amplifiers, A/Dconverters and D/A converters, must have large linear dynamic
ranges. If the peak signal goes into the non-linearregion of devices at the transmitter,a series of
undesirable interference is encountered, such as high out of band radiation and inter-
modulationdistortion. Therefore PAPR reduction techniques are requiredfor OFDM systems.
The power output has large fluctuations due to which, the high power amplifier (HPA) should
have largedynamic range. This results in poor power efficiency.
OFDM systems combine a number of independent sub carriers which causes increase in PAPR.
The increase in PAPR is related to the number of sub carriers and their order of modulation. A
curve called as Complementary Cumulative Distribution Function (CCDF)is used to present the
vital information regarding the OFDM signal to be transmitted. These curves also provide the
PAPR data needed by component designer. The main use of power CCDF curves is to identify
the power characteristic of the signals which are amplified, mixed and decoded [12]. The plot
of relative power levels of signal against their probability of occurrence is called CCDF curve.
5. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
147
This curve illustrates the amount of time the signal remains at or above a given threshold level
[13, 14]. The ratio between power level and the average power is expressed in dBas:
CCDF=Prob(PAPR > ) (6)
where is the threshold level.
3. -LAW COMPANDING TECHNIQUE
In an OFDM system,large signals occur very infrequently therefore itis similar to thespeech
signal, so the same companding technique can be used to improve the OFDM transmission
performance. One of the companding technique named asµ-Law Companding can effectively
reduce the Peak to Average Power Ratio (PAPR) of the transmitted or the companded OFDM
signals by transforming the statistics of the amplitudes of these signals into uniform
distribution. The key idea of the µ-law companderis that it covers all the encountered
amplitudes of the OFDM signal. In µ-law companding, the uniform distribution of the signals
can be obtained by compressing the peak signals and expanding the small signals. In the
process of companding, the amplitudes of the small signalsget enlarged, while the peaks remain
unchanged. Therefore, the average power is increased and thus the PeaktoAverage Power Ratio
(PAPR) can be reduced. This technique overcomes the deficiencies that are caused by clipping
the original OFDM signal. The other advantage of the companding transform is that, it
eliminates the Out of Band Interference (OBI) and can also maintain a constant average power
level and also.
The original OFDM signal is converted into the companded signal by using the Mu
Companding Transform. The companded signal obtained by using the MuCompanding
Transform is given by the equation as:
( )=
( ) ( | |)
( )
(7)
Where, ( )=Companded Signal obtained byµ-LawCompandingTechnique,
( )=sign function,
=original OFDM signal,
µ=255 and it is the Mu-Law parameter of the compander, which controls the amount
ofcompression.
4. DISCRETE COSINE TRANSFORM-II
The discrete cosine transforms (DCT) is a Fourier-related transform similar to the discrete
Fourier transform (DFT). It is a member of a family of sinusoidal unitary transforms. This
transform is real, orthogonal and separable with fast algorithms for its computation. They have
abetter job of concentrating energy and compression of audio and data. The Discrete Cosine
Transform (DCT) was first proposed by Ahmed et al. (1974) [15]. It is a Fourier-like
transform, which equivalent to a DFT of roughly twice the length, operating on real data with
even symmetry. The discrete cosine transform-II is a linear, invertible function F: ;
whereR denotes the set of real numbers, or equivalently an n × n square matrix. Then real
numbers ,…, are transformed into the n real numbers ,…, according to one of the
formulas:
6. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
148
The DCT-II implies the boundary conditions: is even around k=-1/2 and even around k=n-
1/2; is even around j=0 and odd around j=n.
The DCT II is important because it has better computational efficiency, superiority in
bandwidth compression of a wide range of signals, its powerful performance in the bit-rate
reduction and robust against inter carrier interference (ICI). The precoding based techniques are
simple and linear techniques with less complexity to implement without the need of any side
information.
5. PROPOSED SCHEME
A new technique named as precoding technique is also used in OFDM systems to
reduce the PAPR. Precoding techniques obtain a signal with lower PAPR than in the case of a
without precoded OFDM system and it also reduces the interference produced by multiple
users. The µ-LawCompanding Transform also causes less spectrum side-lobes as compared to
other reduction techniques.In proposed scheme µ-Law companding was combined with
precoding technique called Discrete Cosine Transform-II. The combined techniques based
OFDM system was shown in fig. 2. In the transmitter, firstly DCT-II is used to transform the
parallel data stream, and then the transformed data is processed by the companding unit. If data
block passed by DCT-II, before IFFT, the PAPR is reduced, then the PAPR of OFDM signal
could be further reduced by companding.
Fig. 2 Block scheme of DCT-II Precoding technique withµ-law companding in OFDM system
7. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
149
After applying the DCT-II on OFDM signal the signal get compressed decreasing the PAPR
value. Mucompanding is performed on the I and Q outputs of the IFFT after precoding. As the
word length at the IFFT output is decreased, the power consumption and complexity of the
DAC/ADC decreases. Also companding at the IFFT output increases the resolution giving a
better average signal.
6. SIMULATION RESULTS
To reduce the PAPR, the above discussed has been designed and results are shown in the form
of CCDF vs. PAPR plot for different modulations and different values of M. In simulation, an
OFDM system is considered under an additive white Gaussian noise (AWGN ) channel, where
data is randomly generated with subcarriers N=2400, then the signal is modulated by M-PSK
and M-QAM respectively. The PAPR reduction capability is measured by the complementary
cumulative distribution (CCDF = Prob (PAPR>PAPR0), which indicates the probability that
PAPR is above a certain threshold. We compared the simulation results of proposed system
with DCT-II precoded OFDM signal and precodedµ-Law companded signal. The results were
observed for precoded signal and for precodedµ-Law companded signal.
6.1 M-PSK Modulation
In this section µ-Law companding technique is applied over DCT-II precoded OFDM signal
with phase shift keying modulation. We assume CCDF clip rate of 10 .
using M-ary PSK
technique for N=2400 and M=16, 32, 64, 128,256, 512 and 1024.
Fig. 3: CCDF of µ-Law companding with proposed DCT-II technique for 16 PSK
For OFDM system CCDF vs. PAPR plots using M=16 over AWGN channel is shown in Fig. 3.
The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 0.53
dB using PSK modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
6 6.5 7 7.5 8 8.5 9
10
-2
10
-1
10
0
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
8. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
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Fig. 4: CCDF of µ-Law companding with proposed DCT-II technique for 32 PSK
For OFDM system CCDF vs. PAPR plots using M=32 over AWGN channel is shown in Fig. 4.
The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 0.51
dB using PSK modulation. The proposed precodedµ-Law companded technique provides much
reduction in PAPR value as compared to DCT-II precoded signal.
Fig. 5: CCDF of µ-Law companding with proposed DCT-II technique for 64 PSK
For OFDM system CCDF vs. PAPR plots using M=64 over AWGN channel is shown in Fig. 5.
The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 0.7 dB
using PSK modulation. The proposed precoded µ-Law companded technique provides much
reduction in PAPR value as compared to DCT-II precoded signal.
5 5.5 6 6.5 7 7.5 8 8.5 9
10
-2
10
-1
10
0
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(W HT OFDM)
(Mu-Companded)
5 5.5 6 6.5 7 7.5 8 8.5
10
-0.9
10
-0.7
10
-0.5
10
-0.3
10
-0.1
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
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151
Fig. 6: CCDF of µ-Law companding with proposed DCT-II technique for 128 PSK
For OFDM system CCDF vs. PAPR plots using M=128 over AWGN channel is shown in Fig.
6. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 1.03
dB using PSK modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
Fig. 7: CCDF of µ-Law companding with proposed DCT-II technique for 256 PSK
For OFDM system CCDF vs. PAPR plots using M=256 over AWGN channel is shown in Fig.
7. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 0.65
dB using PSK modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
5 6 7 8 9 10 11
10
-0.9
10
-0.7
10
-0.5
10
-0.3
10
-0.1
PAPRReduction for PSK Modulation
PAPR0
CCDF
(WHTOFDM)
(Mu-Companded)
6 6.5 7 7.5 8 8.5 9
10
-0.8
10
-0.7
10
-0.6
10
-0.5
10
-0.4
10
-0.3
10
-0.2
10
-0.1
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
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Fig. 8: CCDF ofµ-Law companding with proposed DCT-II technique for 512 PSK
For OFDM system CCDF vs. PAPR plots using M=512 over AWGN channel is shown in Fig.
8. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 1.02
dB using PSK modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
Fig. 9: CCDF of µ-Law companding with proposed DCT-II technique for 1024 PSK
For OFDM system CCDF vs. PAPR plots using M=1024 over AWGN channel is shown in Fig.
9. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 0.62
dB using PSK modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
6.2 M-QAM Modulation
For M=16, 64, 256 and 1024 M-ary quadrature amplitude modulation (QAM) technique is used
here at CCDF rate of 10 .
.
6 6.5 7 7.5 8 8.5 9
10
-0.7
10
-0.6
10
-0.5
10
-0.4
10
-0.3
10
-0.2
10
-0.1
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(W HT OFDM)
(Mu-Companded)
5.5 6 6.5 7 7.5 8
10
-0.7
10
-0.6
10
-0.5
10
-0.4
10
-0.3
10
-0.2
10
-0.1
PAPR Reduction for PSK Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
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153
Fig. 10: CCDF ofµ-Law companding with proposed DCT-II technique for 16 QAM
For OFDM system CCDF vs. PAPR plots using M=16 over AWGN channel is shown in Fig.
10. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by
0.87 dB using QAM modulation. The proposed precoded µ-Law companded technique
provides much reduction in PAPR value as compared to DCT-II precoded signal.
Fig. 11: CCDF of µ-Law companding with proposed DCT-II technique for 64 QAM
For OFDM system CCDF vs. PAPR plots using M=64 over AWGN channel is shown in Fig.
11. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by
0.83 dB using QAM modulation. The proposed µ-Law companded technique provides much
reduction in PAPR value as compared to DCT-II precoded signal.
4.5 5 5.5 6 6.5 7 7.5 8 8.5 9
10
-2
10
-1
10
0
PAPR Reduction for QAM2 Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
5.5 6 6.5 7 7.5 8 8.5 9 9.5
10
-0.9
10
-0.7
10
-0.5
10
-0.3
10
-0.1
PAPR Reduction for QAM Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
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154
Fig. 12: CCDF of µ-Law companding with proposed DCT-II technique for 256 QAM
For OFDM system CCDF vs. PAPR plots using M=256 over AWGN channel is shown in Fig.
12. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by
1.23 dB using QAM modulation. The proposed precoded µ-Law companded technique
provides much reduction in PAPR value as compared to DCT-II precoded signal.
Fig. 13: CCDF of µ-Law companding with proposed DCT-II technique for 1024 QAM
For OFDM system CCDF vs. PAPR plots using M=1024 over AWGN channel is shown in Fig.
13. The graph gives the clear idea that at CCDF rate of 10 .
the PAPR value decreases by 1.3
dB using QAM modulation. The proposed precoded µ-Law companded technique provides
much reduction in PAPR value as compared to DCT-II precoded signal.
7. CONCLUSIONS
In this paper, a new idea about the performance of the µ-Law companding technique combined
with precoded technique is presented for the reduction of PAPR value. The PAPR value can be
reduced for different modulation formats and for different values of M by using proposed
6 6.5 7 7.5 8 8.5 9
10
-0.8
10
-0.7
10
-0.6
10
-0.5
10
-0.4
10
-0.3
10
-0.2
10
-0.1
PAPR Reduction for QAM Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
5 5.5 6 6.5 7 7.5 8
10
-0.7
10
-0.6
10
-0.5
10
-0.4
10
-0.3
10
-0.2
10
-0.1
PAPR Reduction for QAM Modulation
PAPR0
CCDF
(WHT OFDM)
(Mu-Companded)
13. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
155
scheme without increasing the system complexity. The scheme shows superiority in bandwidth
compression of signals and powerful performance in the bit-rate reduction. This system
produce the lowest PAPR and is efficient, signal independent, distortion less and does not
causes any spectrum side-lobes. The simulation results shows, that the proposed precoded
combinedµ-law companding method displays a better PAPR reduction performance than the
simple DCT-II precoded OFDM signal. Thus, it is concluded that the proposed scheme reduces
PAPR effectively compared with precoded DCT-II transform.
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[16] L. Kansal, A. Kansal& K. Singh, “Analysis of Different High Level Modulation Techniques for
OFDM System,” International Journal of VLSI and Signal Processing Applications, Vol. 1, Issue:
2, 2011.
[17] L. Kansal, A. Kansal& K. Singh, “Performance Analysis of MIMO-OFDM System Using
QOSTBC Code Structure for M-PSK,” Signal Processing: An International Journal, Vol. 5, Issue:
2, 2011.
[18] N. Kaur& L. Kansal, “Reducing the Peak to Average Power Ratio of OFDM Signals through
Walsh Hadamard Transform,” Global Journal of Researches in Engineering, Vol. 13, Issue: 1,
2013.
[19] N. Kaur& L. Kansal, “Peak to Average Power Ratio Reduction of OFDM Signal by Combining
Clipping withWalsh Hadamard Transform,”International Journal of Wireless& Mobile
Networks,Vol. 5, Issue: 1, 2013.
Authors
NavneetKaur was born in Kapurthala .She has done her B.Tech degree in
Electronics and Communication Engineering from LovelyProfessional University,
Phagwara, India. She is currently pursuing her M.Tech degree from Lovely
Professional University, Phagwara, India. Her research area includes Digital
Communication & Wireless Communication.
Lavish Kansal was born in Bathinda.He received his B.Tech degree in
Electronics and Communication Engineering from PTU, Jalandhar in 2009 and
M.E. degree in Electronics and Communication Engineering from Thapar
University, Patiala in 2011. He is working as Assistant Professor in the department
of Electronics and communication Engineering, Lovely Professional University,
Phagwara, India. He has published 15 papers in International journals. His research
area includes Digital Signal Processing, Digital Communication & Wireless
Communication.
International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
156
[16] L. Kansal, A. Kansal& K. Singh, “Analysis of Different High Level Modulation Techniques for
OFDM System,” International Journal of VLSI and Signal Processing Applications, Vol. 1, Issue:
2, 2011.
[17] L. Kansal, A. Kansal& K. Singh, “Performance Analysis of MIMO-OFDM System Using
QOSTBC Code Structure for M-PSK,” Signal Processing: An International Journal, Vol. 5, Issue:
2, 2011.
[18] N. Kaur& L. Kansal, “Reducing the Peak to Average Power Ratio of OFDM Signals through
Walsh Hadamard Transform,” Global Journal of Researches in Engineering, Vol. 13, Issue: 1,
2013.
[19] N. Kaur& L. Kansal, “Peak to Average Power Ratio Reduction of OFDM Signal by Combining
Clipping withWalsh Hadamard Transform,”International Journal of Wireless& Mobile
Networks,Vol. 5, Issue: 1, 2013.
Authors
NavneetKaur was born in Kapurthala .She has done her B.Tech degree in
Electronics and Communication Engineering from LovelyProfessional University,
Phagwara, India. She is currently pursuing her M.Tech degree from Lovely
Professional University, Phagwara, India. Her research area includes Digital
Communication & Wireless Communication.
Lavish Kansal was born in Bathinda.He received his B.Tech degree in
Electronics and Communication Engineering from PTU, Jalandhar in 2009 and
M.E. degree in Electronics and Communication Engineering from Thapar
University, Patiala in 2011. He is working as Assistant Professor in the department
of Electronics and communication Engineering, Lovely Professional University,
Phagwara, India. He has published 15 papers in International journals. His research
area includes Digital Signal Processing, Digital Communication & Wireless
Communication.
International Journal of Wireless & Mobile Networks (IJWMN) Vol. 5, No. 2, April 2013
156
[16] L. Kansal, A. Kansal& K. Singh, “Analysis of Different High Level Modulation Techniques for
OFDM System,” International Journal of VLSI and Signal Processing Applications, Vol. 1, Issue:
2, 2011.
[17] L. Kansal, A. Kansal& K. Singh, “Performance Analysis of MIMO-OFDM System Using
QOSTBC Code Structure for M-PSK,” Signal Processing: An International Journal, Vol. 5, Issue:
2, 2011.
[18] N. Kaur& L. Kansal, “Reducing the Peak to Average Power Ratio of OFDM Signals through
Walsh Hadamard Transform,” Global Journal of Researches in Engineering, Vol. 13, Issue: 1,
2013.
[19] N. Kaur& L. Kansal, “Peak to Average Power Ratio Reduction of OFDM Signal by Combining
Clipping withWalsh Hadamard Transform,”International Journal of Wireless& Mobile
Networks,Vol. 5, Issue: 1, 2013.
Authors
NavneetKaur was born in Kapurthala .She has done her B.Tech degree in
Electronics and Communication Engineering from LovelyProfessional University,
Phagwara, India. She is currently pursuing her M.Tech degree from Lovely
Professional University, Phagwara, India. Her research area includes Digital
Communication & Wireless Communication.
Lavish Kansal was born in Bathinda.He received his B.Tech degree in
Electronics and Communication Engineering from PTU, Jalandhar in 2009 and
M.E. degree in Electronics and Communication Engineering from Thapar
University, Patiala in 2011. He is working as Assistant Professor in the department
of Electronics and communication Engineering, Lovely Professional University,
Phagwara, India. He has published 15 papers in International journals. His research
area includes Digital Signal Processing, Digital Communication & Wireless
Communication.