IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Optical Spatial Modulation with Transmitter-Receiver AlignmentsMarwan Hammouda
This paper proposes an optical spatial modulation (OSM) technique to enhance the data rate of indoor optical wireless communication systems. OSM works by activating only one out of multiple light emitting diodes at each time instant to transmit data. The paper shows that properly aligning the positions and orientations of the transmit and receive units can significantly improve the performance of OSM by decorrelating the optical MIMO channel. Through alignment, the paper achieves a 14 dB gain in signal-to-noise ratio required for a bit-error rate of 10^-3 compared to misaligned setups. The paper also compares the power and bandwidth efficiency of OSM to on-off keying, pulse position modulation, and pulse amplitude modulation.
Optical Spatial Modulation OFDM using Micro LEDsBasil Jacob
An insight into the latest technology that could become the corner stone of Li-Fi technology. It mainly compares the OSM-OFDM with Optical Spatial Multiplexing OFDM based on the reference publications.
525Optimization of Inter-satellite Link (ISL) in Hybrid OFDM-IsOWC Transmissi...idescitation
Inter-satellite optical wireless communication
system (IsOWC), one of the important applications of FSO
(Free Space Optics) technology, will be deployed in space in
the near future because of providing power efficient and high
bandwidth allocation facilities unlike present microwave
satellite systems. In this paper, we have deliberated a novel
model of OFDM-IsOWC system using OPTISYSTEM T M
simulator to optimize an inter-satellite link (ISL) between
satellites with acceptable SNR and BER, which is not reported
in previous investigated work.
STUDY OF ARRAY BI-CONICAL ANTENNA FOR DME APPLICATIONSijwmn
This document summarizes the study of a linear array bi-conical antenna designed for Distance Measuring Equipment (DME) applications. The antenna consists of multiple bi-conical elements arranged in a linear configuration. Simulation results show that increasing the number of elements from 1 to 10 increases the maximum gain from 2 dB to 10.2 dB. This high gain linear array bi-conical antenna design is suitable for use in terrestrial DME ground stations due to its large size. The antenna operates within the DME frequency band of 960-1215 MHz.
The effects of optical nonlinearities in optical fibers are ubiquitous. These effects can be deleterious, but
also have many useful applications, especially in the field of implementing all-optical functionalities in optical
networks. The paper is devoted to modeling the evolution of signal at 400 Gbps during non linear propagation for
DP 16-QAM modulation format in order to show the impact of optical launch power and fiber span transmission
on the propagation. This study is focused on the non linear propagation of fiber to obtain the relationship between
Optical Launch Power (OLP) and Error Vector Magnitude (EVM). It is found that the for the range of launch
power (-8dBm to 4dBm) , EVM is below 16%.
Keywords: DP, EVM, OLP, QAM.
Optical Spatial Modulation with Transmitter-Receiver AlignmentsMarwan Hammouda
This paper proposes an optical spatial modulation (OSM) technique to enhance the data rate of indoor optical wireless communication systems. OSM works by activating only one out of multiple light emitting diodes at each time instant to transmit data. The paper shows that properly aligning the positions and orientations of the transmit and receive units can significantly improve the performance of OSM by decorrelating the optical MIMO channel. Through alignment, the paper achieves a 14 dB gain in signal-to-noise ratio required for a bit-error rate of 10^-3 compared to misaligned setups. The paper also compares the power and bandwidth efficiency of OSM to on-off keying, pulse position modulation, and pulse amplitude modulation.
Optical Spatial Modulation OFDM using Micro LEDsBasil Jacob
An insight into the latest technology that could become the corner stone of Li-Fi technology. It mainly compares the OSM-OFDM with Optical Spatial Multiplexing OFDM based on the reference publications.
525Optimization of Inter-satellite Link (ISL) in Hybrid OFDM-IsOWC Transmissi...idescitation
Inter-satellite optical wireless communication
system (IsOWC), one of the important applications of FSO
(Free Space Optics) technology, will be deployed in space in
the near future because of providing power efficient and high
bandwidth allocation facilities unlike present microwave
satellite systems. In this paper, we have deliberated a novel
model of OFDM-IsOWC system using OPTISYSTEM T M
simulator to optimize an inter-satellite link (ISL) between
satellites with acceptable SNR and BER, which is not reported
in previous investigated work.
STUDY OF ARRAY BI-CONICAL ANTENNA FOR DME APPLICATIONSijwmn
This document summarizes the study of a linear array bi-conical antenna designed for Distance Measuring Equipment (DME) applications. The antenna consists of multiple bi-conical elements arranged in a linear configuration. Simulation results show that increasing the number of elements from 1 to 10 increases the maximum gain from 2 dB to 10.2 dB. This high gain linear array bi-conical antenna design is suitable for use in terrestrial DME ground stations due to its large size. The antenna operates within the DME frequency band of 960-1215 MHz.
The effects of optical nonlinearities in optical fibers are ubiquitous. These effects can be deleterious, but
also have many useful applications, especially in the field of implementing all-optical functionalities in optical
networks. The paper is devoted to modeling the evolution of signal at 400 Gbps during non linear propagation for
DP 16-QAM modulation format in order to show the impact of optical launch power and fiber span transmission
on the propagation. This study is focused on the non linear propagation of fiber to obtain the relationship between
Optical Launch Power (OLP) and Error Vector Magnitude (EVM). It is found that the for the range of launch
power (-8dBm to 4dBm) , EVM is below 16%.
Keywords: DP, EVM, OLP, QAM.
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
This document discusses the design and performance analysis of an optical transmission system using different modulation formats. It simulates a long-haul optical transmission system over single-mode fiber. Return-to-zero (RZ) and non-return-to-zero (NRZ) modulation formats are analyzed at 10Gb/s. The performance is investigated based on parameters like Q-factor, bit error rate, eye diagrams, and input power. Simulation results show that RZ modulation has better performance for long-distance transmission systems due to its lower bit error rate, while NRZ is suitable for shorter distances due to its smaller bandwidth requirements.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
This project simulated a 4-channel wavelength division multiplexing system over 120 km of single mode fiber using Optisystem software. The student contributed to the design of the optical transmission line channel, which included erbium-doped fiber amplifiers and dispersion compensation fiber, as well as the receiver design. The best bit error rate obtained was on the order of 10-8. An extension of the design to 64 channels was also implemented. Through this project, the student gained knowledge of WDM and optical fiber technologies.
Minimize MIMO OFDM interference and noise ratio using polynomial-time algorit...IJECEIAES
The document proposes a polynomial-time algorithm to minimize interference and noise ratio for MIMO OFDM systems by correcting frequency offset. It directly maximizes the conditional average signal-to-interference and noise ratio (SINR) of subcarriers on each receiving antenna by correcting the frequency offset. Simulation results show the algorithm slightly outperforms existing methods with 50% lower complexity. It analyzes receive antenna selection and signal processing for MIMO-OFDM based on maximizing conditional average SINR after frequency offset correction on each receive antenna.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
Performance Analysis of Massive MIMO Downlink System with Imperfect Channel S...IJRES Journal
We investigate the ergodic sum rate and required transmit power of a single-cell massive
multiple-input multiple-output (MIMO) downlink system. The system considered in this paper is based on two
linear beamforming schemes, that is, maximum ratio transmission (MRT) beamforming and zero-forcing (ZF)
beamforming. What’s more, we use minimum mean square error (MMSE) channel estimation to get imperfect
channel state information (CSI). Compared with the perfect CSI case, both theoretical analysis and simulation
results show that the system performance is different when the imperfect CSI is taken into account.
This document proposes a method to reduce peak-to-average power ratio (PAPR) in orthogonal frequency-division multiplexing (OFDM) systems using high PAPR sequence scrambling. It uses an array of scramblers to change high PAPR sequences into lower PAPR sequences. Scrambling stops once the PAPR goes below a threshold, reducing complexity compared to conventional selective mapping. Simulation results show the method reduces PAPR over 4dB and most sequences require few or no scramblers. It provides a complexity-reduction tradeoff by selecting the scrambler array size and threshold value.
IRJET- Design and Analysis of LPDA Antenna for through the Wall Detection ...IRJET Journal
This document presents the design, simulation, and analysis of a logarithmic periodic dipole antenna (LPDA) for through-the-wall detection applications operating in the frequency range of 0.5-3 GHz. Key features of the antenna include a gain over 6 dB across the bandwidth, a VSWR less than 2.5, and a directional radiation pattern optimized for detecting targets behind walls. The antenna design was modified from a traditional LPDA by using strip dipoles rather than cylindrical ones and adding a reflector to increase directivity. Simulations showed the antenna meets design requirements for through-wall detection in terms of impedance matching, gain, and minimization of side lobes.
This document discusses models for predicting path loss of sky wave and ground wave propagation in the HF frequency range. It recommends using the ICEPAC program from the IONCAP family to predict sky wave propagation path loss, as it is the most advanced model and has been effectively used for frequency planning. For ground wave propagation prediction, it discusses different models available and the factors that influence path loss, such as ground conductivity.
IRJET- Compressed Sensing based Modified Orthogonal Matching Pursuit in DTTV ...IRJET Journal
This document discusses a modified orthogonal matching pursuit algorithm used for channel estimation in digital terrestrial television systems. It proposes using compressed sensing based channel estimation at the receiver to eliminate sparse information. Thresholding is used to remove noise from the channel estimation and improve signal quality. Simulation results show that bit error rate decreases when the received signal power from different transmitters is almost equal.
This document discusses carrier frequency offset (CFO) in OFDM systems. It begins with an introduction to OFDM and the issues caused by timing offset and CFO. It then describes CFO in more detail, distinguishing between integer and fractional CFO. Methods for CFO estimation are presented, including pilot-based and non-pilot based approaches. Fast acquisition methods for initial CFO estimation are covered, along with references.
A Simple, Accurate Approximation to the Sum of Gamma-Gamma variates and Appli...Anax_Fotopoulos
The document proposes using an alpha-mu distribution to approximate the sum of independent gamma-gamma random variables, which model irradiance in free-space optical communication systems under atmospheric turbulence. This approximation allows accurate yet simple performance analysis of MIMO free-space optical systems in terms of outage probability and average bit error probability. Numerical results validate the proposed approximation method.
This document presents a term project on 3D beamforming for 5G networks. It outlines the motivation for 3D beamforming to meet 5G goals and reduce interference. The objectives are to analyze narrow beam formation with different array geometries and track user movement. Results show narrow beams formed with linear, planar and cylindrical arrays using windowing. Future work includes incorporating 3D channel models and Coordinated Multi-Point features with 3D beamforming.
The document compares coding techniques used to mitigate interference in MU-MIMO systems. It discusses Zero Forcing, Block Diagonalization, Minimum Mean Square Error, and Signal to Leakage Noise Ratio algorithms. A MATLAB simulation was created to analyze the bit error rate performance of each algorithm with varying user numbers. Hardware testing using USRPs and LabVIEW validated the conclusions from the software simulation. It was found that MMSE and SLNR algorithms best addressed noise in the channel and had the lowest error rates, especially with increasing user numbers, due to their use of diversity techniques.
The document discusses Coherent Optical OFDM (CO-OFDM) and analyzes its performance at different data rates such as 1Gbps, 20Gbps, and 100Gbps. 4QAM-OFDM signals are generated and transmitted through 250km of fiber. The results show that distortions in the OFDM spectrum and QAM constellations increase as the data rate increases, due to nonlinearities in the fiber. CO-OFDM has advantages over other modulation formats as it provides both coherent detection and OFDM modulation, but its performance is affected by fiber nonlinearities at high data rates due to its high peak-to-average power ratio.
ANALYTICAL PERFORMANCE EVALUATION OF A MIMO FSO COMMUNICATION SYSTEM WITH DIR...optljjournal
MIMO FSO correspondence is examined as of late to build up a hearty correspondence connects within the sight of atmospheric turbulence. In this paper an analytical approach is developed to assess the impact of atmospheric turbulence on BER performance of a MIMO FSO communication system with Q-ary Pulse Position Modulation (QPPM). Examination is exhibited to discover flag to clamor proportion at the yield of an immediate location collector with optical power modulator under strong turbulent condition which is modeled as gamma-gamma distribution. The outcomes demonstrate that the BER performance is emphatically debased because of the impact of atmospheric turbulence. In any case, the execution can be enhanced by expanding the quantity of transmitters, beneficiaries and request of Q in PPM. Results demonstrate that the FSO MIMO framework with M=8, N=4 Q=4 gives the 22 dB improvement at BER of 10-9 .
ANALYTICAL PERFORMANCE EVALUATION OF A MIMO FSO COMMUNICATION SYSTEM WITH DIR...optljjournal
MIMO FSO correspondence is examined as of late to build up a hearty correspondence connects within the
sight of atmospheric turbulence. In this paper an analytical approach is developed to assess the impact of
atmospheric turbulence on BER performance of a MIMO FSO communication system with Q-ary Pulse
Position Modulation (QPPM). Examination is exhibited to discover flag to clamor proportion at the yield
of an immediate location collector with optical power modulator under strong turbulent condition which is
modeled as gamma-gamma distribution. The outcomes demonstrate that the BER performance is
emphatically debased because of the impact of atmospheric turbulence
This document discusses coherent optical orthogonal frequency division multiplexing (CO-OFDM) for visible light communications. It begins with an introduction describing increasing bandwidth demand and the benefits of CO-OFDM. It then explains the basic principles of coherent optical transmission and CO-OFDM. The document proceeds to describe simulations conducted using OptiSystem software to model a 4-QAM CO-OFDM system over varying transmission distances. The results show degradation of the signal constellation and optical signal-to-noise ratio as distance increases due to attenuation and chromatic dispersion. Finally, the document concludes with a review of the CO-OFDM fundamentals and simulation results.
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
This document discusses the design and performance analysis of an optical transmission system using different modulation formats. It simulates a long-haul optical transmission system over single-mode fiber. Return-to-zero (RZ) and non-return-to-zero (NRZ) modulation formats are analyzed at 10Gb/s. The performance is investigated based on parameters like Q-factor, bit error rate, eye diagrams, and input power. Simulation results show that RZ modulation has better performance for long-distance transmission systems due to its lower bit error rate, while NRZ is suitable for shorter distances due to its smaller bandwidth requirements.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
This project simulated a 4-channel wavelength division multiplexing system over 120 km of single mode fiber using Optisystem software. The student contributed to the design of the optical transmission line channel, which included erbium-doped fiber amplifiers and dispersion compensation fiber, as well as the receiver design. The best bit error rate obtained was on the order of 10-8. An extension of the design to 64 channels was also implemented. Through this project, the student gained knowledge of WDM and optical fiber technologies.
Minimize MIMO OFDM interference and noise ratio using polynomial-time algorit...IJECEIAES
The document proposes a polynomial-time algorithm to minimize interference and noise ratio for MIMO OFDM systems by correcting frequency offset. It directly maximizes the conditional average signal-to-interference and noise ratio (SINR) of subcarriers on each receiving antenna by correcting the frequency offset. Simulation results show the algorithm slightly outperforms existing methods with 50% lower complexity. It analyzes receive antenna selection and signal processing for MIMO-OFDM based on maximizing conditional average SINR after frequency offset correction on each receive antenna.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
Performance Analysis of Massive MIMO Downlink System with Imperfect Channel S...IJRES Journal
We investigate the ergodic sum rate and required transmit power of a single-cell massive
multiple-input multiple-output (MIMO) downlink system. The system considered in this paper is based on two
linear beamforming schemes, that is, maximum ratio transmission (MRT) beamforming and zero-forcing (ZF)
beamforming. What’s more, we use minimum mean square error (MMSE) channel estimation to get imperfect
channel state information (CSI). Compared with the perfect CSI case, both theoretical analysis and simulation
results show that the system performance is different when the imperfect CSI is taken into account.
This document proposes a method to reduce peak-to-average power ratio (PAPR) in orthogonal frequency-division multiplexing (OFDM) systems using high PAPR sequence scrambling. It uses an array of scramblers to change high PAPR sequences into lower PAPR sequences. Scrambling stops once the PAPR goes below a threshold, reducing complexity compared to conventional selective mapping. Simulation results show the method reduces PAPR over 4dB and most sequences require few or no scramblers. It provides a complexity-reduction tradeoff by selecting the scrambler array size and threshold value.
IRJET- Design and Analysis of LPDA Antenna for through the Wall Detection ...IRJET Journal
This document presents the design, simulation, and analysis of a logarithmic periodic dipole antenna (LPDA) for through-the-wall detection applications operating in the frequency range of 0.5-3 GHz. Key features of the antenna include a gain over 6 dB across the bandwidth, a VSWR less than 2.5, and a directional radiation pattern optimized for detecting targets behind walls. The antenna design was modified from a traditional LPDA by using strip dipoles rather than cylindrical ones and adding a reflector to increase directivity. Simulations showed the antenna meets design requirements for through-wall detection in terms of impedance matching, gain, and minimization of side lobes.
This document discusses models for predicting path loss of sky wave and ground wave propagation in the HF frequency range. It recommends using the ICEPAC program from the IONCAP family to predict sky wave propagation path loss, as it is the most advanced model and has been effectively used for frequency planning. For ground wave propagation prediction, it discusses different models available and the factors that influence path loss, such as ground conductivity.
IRJET- Compressed Sensing based Modified Orthogonal Matching Pursuit in DTTV ...IRJET Journal
This document discusses a modified orthogonal matching pursuit algorithm used for channel estimation in digital terrestrial television systems. It proposes using compressed sensing based channel estimation at the receiver to eliminate sparse information. Thresholding is used to remove noise from the channel estimation and improve signal quality. Simulation results show that bit error rate decreases when the received signal power from different transmitters is almost equal.
This document discusses carrier frequency offset (CFO) in OFDM systems. It begins with an introduction to OFDM and the issues caused by timing offset and CFO. It then describes CFO in more detail, distinguishing between integer and fractional CFO. Methods for CFO estimation are presented, including pilot-based and non-pilot based approaches. Fast acquisition methods for initial CFO estimation are covered, along with references.
A Simple, Accurate Approximation to the Sum of Gamma-Gamma variates and Appli...Anax_Fotopoulos
The document proposes using an alpha-mu distribution to approximate the sum of independent gamma-gamma random variables, which model irradiance in free-space optical communication systems under atmospheric turbulence. This approximation allows accurate yet simple performance analysis of MIMO free-space optical systems in terms of outage probability and average bit error probability. Numerical results validate the proposed approximation method.
This document presents a term project on 3D beamforming for 5G networks. It outlines the motivation for 3D beamforming to meet 5G goals and reduce interference. The objectives are to analyze narrow beam formation with different array geometries and track user movement. Results show narrow beams formed with linear, planar and cylindrical arrays using windowing. Future work includes incorporating 3D channel models and Coordinated Multi-Point features with 3D beamforming.
The document compares coding techniques used to mitigate interference in MU-MIMO systems. It discusses Zero Forcing, Block Diagonalization, Minimum Mean Square Error, and Signal to Leakage Noise Ratio algorithms. A MATLAB simulation was created to analyze the bit error rate performance of each algorithm with varying user numbers. Hardware testing using USRPs and LabVIEW validated the conclusions from the software simulation. It was found that MMSE and SLNR algorithms best addressed noise in the channel and had the lowest error rates, especially with increasing user numbers, due to their use of diversity techniques.
The document discusses Coherent Optical OFDM (CO-OFDM) and analyzes its performance at different data rates such as 1Gbps, 20Gbps, and 100Gbps. 4QAM-OFDM signals are generated and transmitted through 250km of fiber. The results show that distortions in the OFDM spectrum and QAM constellations increase as the data rate increases, due to nonlinearities in the fiber. CO-OFDM has advantages over other modulation formats as it provides both coherent detection and OFDM modulation, but its performance is affected by fiber nonlinearities at high data rates due to its high peak-to-average power ratio.
ANALYTICAL PERFORMANCE EVALUATION OF A MIMO FSO COMMUNICATION SYSTEM WITH DIR...optljjournal
MIMO FSO correspondence is examined as of late to build up a hearty correspondence connects within the sight of atmospheric turbulence. In this paper an analytical approach is developed to assess the impact of atmospheric turbulence on BER performance of a MIMO FSO communication system with Q-ary Pulse Position Modulation (QPPM). Examination is exhibited to discover flag to clamor proportion at the yield of an immediate location collector with optical power modulator under strong turbulent condition which is modeled as gamma-gamma distribution. The outcomes demonstrate that the BER performance is emphatically debased because of the impact of atmospheric turbulence. In any case, the execution can be enhanced by expanding the quantity of transmitters, beneficiaries and request of Q in PPM. Results demonstrate that the FSO MIMO framework with M=8, N=4 Q=4 gives the 22 dB improvement at BER of 10-9 .
ANALYTICAL PERFORMANCE EVALUATION OF A MIMO FSO COMMUNICATION SYSTEM WITH DIR...optljjournal
MIMO FSO correspondence is examined as of late to build up a hearty correspondence connects within the
sight of atmospheric turbulence. In this paper an analytical approach is developed to assess the impact of
atmospheric turbulence on BER performance of a MIMO FSO communication system with Q-ary Pulse
Position Modulation (QPPM). Examination is exhibited to discover flag to clamor proportion at the yield
of an immediate location collector with optical power modulator under strong turbulent condition which is
modeled as gamma-gamma distribution. The outcomes demonstrate that the BER performance is
emphatically debased because of the impact of atmospheric turbulence
This document discusses coherent optical orthogonal frequency division multiplexing (CO-OFDM) for visible light communications. It begins with an introduction describing increasing bandwidth demand and the benefits of CO-OFDM. It then explains the basic principles of coherent optical transmission and CO-OFDM. The document proceeds to describe simulations conducted using OptiSystem software to model a 4-QAM CO-OFDM system over varying transmission distances. The results show degradation of the signal constellation and optical signal-to-noise ratio as distance increases due to attenuation and chromatic dispersion. Finally, the document concludes with a review of the CO-OFDM fundamentals and simulation results.
Average Channel Capacity of Amplify-and-forward MIMO/FSO Systems Over Atmosph...IJECEIAES
In amplify-and-forward (AF) relay channel, when the direct link between source and destination terminals is deeply faded, the signal from the source terminal to the destination terminal propagates through the relay terminals, each of which relays a signal received from the previous terminal to the next terminal in series. This paper, we theoretically analyze the performance of multiple-input multiple-output (MIMO) AF free-space optical (FSO) systems. The AF-MIMO/FSO average channel capacity (ACC), which is expressed in terms of average spectral efficiency (ASE) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel. They are modeled by log-normal and the gamma-gamma distributions for the cases of weak-to-strong turbulence conditions. We extract closed form mathematical expression for the evaluation of the ACC and we quantitatively discuss the influence of turbulence strength, link distance, different number of relay stations and different MIMO configurations on it.
Decimal convertor application for optical wireless communication by generatin...University of Malaya (UM)
This document proposes a system to generate dark and bright optical soliton pulses for use in secure wireless communication networks. It uses microring resonators to generate multiple wavelengths of optical pulses. These pulses are then sent through a polarization control system to encode them as quantum codes using dark and bright solitons. The soliton pulses can then be converted to digital logic codes using a decimal converter and transmitted securely over wireless networks. The system is able to generate multi-wavelength soliton pulses ranging from 1.55 to 1.56 micrometers with a full width at half maximum of 10 picometers and a free spectral range of 600 picometers.
Decimal Convertor Application for Optical Wireless Communication by Generatin...University of Malaya (UM)
Two systems consist of microring resonators (MRRs) and an add/drop filter are used to generate signals as localized multi wavelengths. Quantum dense encoding
can be performed by output signals of selected wavelengths incorporated to a polarization control system. Therefore dark and bright optical soliton pulses
with different time slot are generated. They can be converted into digital logic quantum codes using a decimal convertor system propagating along a wireless networks. Results show that multi soliton wavelength, ranged from 1.55 m to 1.56 m with FWHM and FSR of 10 pm and 600 pm can be generated respectively. Keywords- Micro Ring Resonator, Quantum Dense Coding (QDC), Wireless network communication system.
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6 ijaems jan-2016-15-comparative analysis of free space optics and single mod...INFOGAIN PUBLICATION
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Performance Analysis of M-ary Optical CDMA in Presence of Chromatic DispersionIDES Editor
The performance of M-ary optical code division
multiple access (OCDMA) is analytically investigated in
presence of chromatic dispersion. The study is carried out for
single mode dispersion shifted and non dispersion shifted
fibers. Walsh code is used as user address. The p-i-n
photodetector is used for optoelectronic conversion process.
In our proposed model 16 different symbols are modulated
with different intensity levels and detected by direct detection
technique. The numerical results show that, the reconstruction
of the transmitted symbol is strongly dependent on the received
symbols magnitude which is reduced by fiber length and
symbol rate. It is found that the proposed OCDMA system
shows better performance when dispersion shifted fiber is
used as a communication medium.
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Raman amplifier performance in pre-amplifier use for optical fiber communicat...TELKOMNIKA JOURNAL
The development of telecommunications networks is currently dominated by fiber optics. The fiber optic has become a waveguide medium transmitting information with high frequency bands, high capacity and high speed. An optical amplifier is required to maintain electromagnetic signals when they propagate in far distance. One of the amplifiers, Fiber Raman Amplifiers (FRA) which is the light scattering from the light that comes with the phonon in the lattice of amplification medium produces photons that are coherent with the incoming photons. Many amplifiers are commonly used but the problems not only come from the amplifier but also the component circuit and system. By simulation method, FRA circuit is designed and operated in the form of pre-amplifiers to maintain a better signal from material interference and geometry. The simulation results show that the lowest BER value and the highest Q-factor are found at a distance of 10 km depicted by eye diagram.
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Investigation of optimal duty cycle for gvd undercompensatedIAEME Publication
This document summarizes an investigation into optimizing the duty cycle of input pulses in an undercompensated optical fiber link. The link consists of 5 loops, each with 50km of standard single mode fiber followed by dispersion compensating fiber. Simulation results show that higher duty cycle pulses (66-75%) permit greater undercompensation (up to 1.3% reduction in dispersion compensating fiber length) while maintaining reliable communication compared to lower duty cycle pulses (25-33%) which only tolerate up to 1% undercompensation. The optimal duty cycle balances fiber nonlinearities and accumulated dispersion to maximize the quality factor over the greatest range of input powers for a given level of undercompensation.
This document proposes a pilot-tone assisted log-likelihood ratio (PT-LLR) metric for LDPC-coded coherent optical OFDM systems with linear phase noise. The PT-LLR incorporates knowledge of the common phase error obtained from the pilot-tone, eliminating the need for prior phase compensation. It is derived and shown to outperform the conventional LLR metric for higher-order modulations at lower pilot-tone power ratios, with similar complexity. Blind intercarrier interference mitigation prior to LLR calculation further improves performance under larger laser linewidths. Simulation results demonstrate the LDPC coded CO-OFDM system using the proposed PT-LLR metric.
This document presents a pilot-tone assisted log-likelihood ratio (PT-LLR) metric for LDPC-coded coherent optical OFDM systems with linear phase noise. The PT-LLR incorporates knowledge of the common phase error (CPE) obtained from the pilot-tone, eliminating the need for prior CPE estimation and compensation. It is derived and shown to outperform the conventional LLR metric for higher-order modulations at smaller pilot-tone to signal power ratios, with similar complexity. Blind intercarrier interference mitigation prior to LLR calculation further improves performance under larger laser linewidths. Simulation results demonstrate the LDPC coded CO-OFDM system using the new PT-LLR metric.
Comparative Analysis of DP QPSK and DP 16-QAM Optical Coherent Receiver, with...IRJET Journal
This document compares DP QPSK and DP 16-QAM optical coherent receivers in terms of average bit error rate (BER) when analyzing phase noise. It simulates a 112 Gbps DP 16-QAM and DP QPSK coherent receiver system with digital signal processing (DSP) using Optisystem and MATLAB. The analysis introduces noise before the receiver by varying the optical signal-to-noise ratio (OSNR) and measures average BER. Graphs of average BER versus OSNR are produced for different digital filters and filter orders to determine the filter with minimum phase noise. The DP 16-QAM system shows better power spectrum confinement and is analyzed in more detail.
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Or: Beyond linear.
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Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
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Performance Analysis of Fog Effect on Free Space Optical Communication System
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861.Volume 7, Issue 2 Ver. I (Mar. - Apr. 2015), PP 16-24
www.iosrjournals.org
DOI: 10.9790/4861-07211624 www.iosrjournals.org 16 | Page
Performance Analysis of Fog Effect on Free Space Optical
Communication System
Mazin Ali A. Ali
The University of Mustansiriyah, College of Science, Physics Department, Iraq-Baghdad
Abstract: In this paper, the attenuation of FSO communication systems operating at selected wavelengths of
650nm, 850nm, 950nm and 1550nm in fog models is theoretically analyzed, using 16-PPM and NRZ-OOK
modulation techniques over fog channel. Four fog models are employed for optical beam propagation
horizontally at different wavelengths. The received signal power, SNR is analyzed. The characteristics of bit
error rate BER for 16-PPM and NRZ -OOK optical modulation techniques are studied. Simulation results show
that the performance of 1550nm is more suited for an FSO communication system. On the other hand, we
discuss the suitability of modulation techniques under these fog models.
Keywords: Fog models, modulation, FSO, 16-PPM, NRZ-OOK.
I. Introduction
Free Space Optics (FSO) communication is a technology that uses light as its carrier to transmit data
between two points in the atmosphere channel [1]. Free space optics (FSO) are sensitive to weather conditions –
primary to fog and precipitation – may face with substantial loss of its power during passing through channel[2,
3] The effect of absorption and scattering of the light carrier signal (i. e. Laser) can be described by the path –
dependent attenuation coefficient [4]. A laser communication system is advantageous to radio frequency
communication systems for the following reasons: (i) no licensing requirements or tariffs are required for its
utilization; (ii) its large bandwidth allows very high data rates; (iii) the system is light weight, small, and has
compact dimensions; (iv) it operates with low power consumption. On the other hand, unlike radio frequency
systems, laser communication systems have a very narrow laser beam divergence angle as well as a very narrow
receiver field of view [5]. The proposed model for the prediction of attenuation due to fog is reported in [6-14].
One of the keys of any communication system is the selection of a suitable modulation technique; pulse position
modulation L-PPM can provide higher power efficiency at the expense of increased bandwidth requirement. On
the other hand, on – off – key (OOK-NRZ) is the simplest and widely used modulation scheme in free space
optical communication due to its simplicity in the implementation. OOK-NRZ offers similar power efficiency to
the 2-PPM [15].
II. Attenuation by Fog
For a terrestrial FSO link transmitting optical signal through the atmosphere, the received signal power at a
distance, L from the transmitted signal power for FSO is given by [16]
exp( . )
2
( . )
Arp P Lr t fog
L
(1)
Where A is the receiver area, θ is the full divergence angle; γfog is the fog attenuation factor (dB/km).
The function of γfog(λ) is the total extinction coefficient per unit length, which represents the attenuation
of the transmitted light. It is composed of terms for scattering and absorption, and general it is the sum of the
following terms [17]
( ) ( ) ( ) ( ) ( )m a m a (2)
The first two terms represent the molecular and aerosol absorption coefficients, respectively; while the
last two terms are the molecular and aerosol scattering coefficients respectively. The wavelengths used in FSO
are basically chosen to coincide with the atmospheric transmission windows [7, 18], resulting in the attenuation
coefficient being dominated by scattering the attenuation is reduced to:
( ) ( )aspecific
(3)
Attenuation coefficient based on empirical measurement data was calculated by the following empirical model
[19]
2. Performance Analysis of Fog Effect on Free Space Optical Communication System
DOI: 10.9790/4861-07211624 www.iosrjournals.org 17 | Page
3.91
( )
550a V
(4)
Where V is the visibility in (km), λ represent the wavelength in (nm). The parameter δ depends on the visibility
distance range, according to Kruse model δ is given as [6]
1.6, 50
1.3, 6 50
1/3
0.585. , 6
if V km
if km V km
V if V km
(5)
While Kim model defines δ as [7]:
1.6, 50
1.3, 6 50
0.16 0.34, 0.5 6
0.5, 0.5 1
0, 0.5
if V km
if km V km
V if km V km
V if km V km
if V km
(6)
Al-Naboulsi proposed expressions to predict the wavelength dependent fog attenuation coefficient for the
convection and advection fogs for wavelengths from 690 to 1550 nm [20]. The attenuation coefficient for
convection fog is given by:
0.11478 3.8367
( )
( )
con
V km
(7)
The attenuation coefficient for advection fog is given by:
2
0.18126. 0.13709 3.7205
( )
( )
adv
V km
(8)
The specific attenuation coefficient for both types of fog is given by
10
( ) ( )
ln(10)
dB
specific km
(9)
III. Signal to Noise Ratio& Bit Error Rate
The first features of an FSO communication system is the signal to noise ratio SNR. When transmitted
optical signals arrive at the receiver, they are converted to electronic signals by photo detectors. There are many
types of photo detectors in existence, photodiodes are used almost exclusively in optical communication
applications because of their small size, suitable material, high sensitivity, and fast response time [21]. For the
PIN photodiode the signal to noise ratio (SNR) is given by [22]:
2
2 ( ) 4 /
I p
SNR
qB I I KTBF Rp nD L
(10)
Where Ip is the average photocurrent, q is the charge of an electron(C), B represents the bandwidth, ID is the
dark current, T is the absolute photodiode temperature (K), Fn is the photodiode figure noise equal to 1 for PIN
photodiode, RL is the PIN load resistor. The average photocurrent Ip can be expressed as [23]
.I P Rp r (11)
where Pr is the average optical power received to the photodetector, R is the responsivity of the photodetector.
A second feature of FSO communication systems is the bit error rate BER [24]. The effect of fog on
the Bit Error Rate BER of an FSO link is reported in [25] which correlate the atmospheric transmission with the
BER. However, RZ-OOK and NRZ-OOK modulation schemes are widely used in commercial FSO
communication systems because of their ease of implementation, bandwidth efficiency and cost effectiveness
[26]. The relation BER and SNR for NRZ-OOK modulated signal is as follow [27]:
3. Performance Analysis of Fog Effect on Free Space Optical Communication System
DOI: 10.9790/4861-07211624 www.iosrjournals.org 18 | Page
1 1
2 2 2
BER erfc SNRNRZ OOK
(12)
While BER for L-PPM modulated signal is given by [27, 28]:
1 1
( log )22 22 2
L
BER erfc SNR LL PPM (13)
IV. Numerical Results
In this section, using the above mentioned formulations, the simulation presents the results of analyzing the
performance of FSO communication systems due to fog attenuation channel employing NRZ-OOK, and L-
PMM modulation techniques in the transmitter and Si PIN in a receiver. The values of the simulation parameters
and constants are given in table (1).
Table 1. System parameters used in the simulation [23, 29, 30, 31]
1. Received signal power as a function of distance
Let us first see the effect of the distance on the received optical power Pr, it is considered that the
visibility is 1 km. It is shown in Fig. (1-4) curves of Pr as a function of distance for four fog model types and
four extreme cases of wavelengths. Let us assume a tolerable loss of −50 dBm beyond which the signal is not
detectable at the receiver. We notice that, for λ =650 nm, the transmission range is limited to 0.5 km for the fog
models under study. When the wavelength is increasing (λ = 850, 950 nm) increases dramatically these ranges,
obviously, it allows range limits increases to 0.58 km for 850nm and but 0.6 km for 950nm when Kim & Kruse
models are applied. When the wavelength 1550 nm is used, Kim & Kruse models can be working at long
ranges reached to 0.72 km and 0.78km, respectively. But for AL-Naboulsi models (Advection & convection)
stay about 0.5 km for the wavelengths applied in simulation.
Fig (1) Received Signal Power for 650nm
Parameter Value
Visibility 1 km
Transmitter power (PT) 50 mw
Receiver Area (A) 10cm
Laser beam divergence angle θ 1mrad
Electron charge (q) 1.6×10-19
C
PIN load resistance (RL) 1kΩ
Boltzmann constant (k) 1.38×10-23
J.k
Temperature (T) 298K
Dark current (ID) 10nA
Responsivity (R) 0.6A/W`
Bandwidth (B) 0.5GHz
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Fig (2) Received Signal Power for 850nm
Fig (3) Received Signal Power for 950nm
Fig (4) Received Signal Power for 1550nm
2. SNR as a function of distance
The SNR of different fog models is compared in Fig. (5-9). The SNR increases with increasing
wavelengths. It is achieved that 1550 nm has presented the highest SNR compared with the other wavelengths
under the same operating conditions. On the other hand, it can be seen that the Kim & Kruse Models are more
sensitive to foggy weather, while AL–Naboulsi models (Advection and convection) are having value about 0.85
km for different wavelengths under study.
Fig (5) SNR for 650 nm
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Fig (6) SNR for 850 nm
Fig (7) SNR for 950 nm
Fig (8) SNR for 1550 nm
3. BER Characteristics for FSO Communication
BER plays an essential function in an optical communication system. We present here simulation
results to compare the performance of fog attenuation under different mathematical models. It is considered that
16-PPM and NRZ-OOK modulation techniques in the transmitter side because of its simplicity and resilience in
the FSO communication system.
3. 1 The Impact of the distance
Let us consider the BER performance as a function of the distance. Fig (9) shows that BER for NRZ-
OOK and 16-PPM modulation format under different fog models when a 650nm is used. In this case, we notice
that for BER 10-10
, when 16-PPM is applied the distance about 0.85 km for Kruse and Kim models, and its
decrease for Al-Naboulsi model becomes about 0.8 km. On the other hand, when NRZ-PPM is applied the
distance is about 0.78 for Kruse and Kim Models, and its decrease for Al –Naboulsi model becomes about 0.73
km. It is observed from Fig. (10) a significant increase in the distance can be achieved by 850nm. For Kruse and
Kim model are utilized the maximum data rate is about 1 km and 0.98km, respectively when 16-ppm is used.
While for Kruse and Kim models becomes 0.89 km and 0.88 km when NRZ-OOK is used. On the other hand,
AL-Naboulsi (Advection and Convection) has the same values remember in fig. (9). Another important
simulation was evaluated the performance of the BER for 950nm. In Figure (11) a significant improvement in
the distance can be achieved by using 950nm, for the BER 10-10
, when 16-PPM is applied; the maximum data
transmission is about 1.1 km for Kruse and 1 km for Kim while its about 0.9 km and 0.85 km for Kruse and Kim
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model respectively; under NRZ-OOK modulation technique. It is observed that in fig. (12), the maximum data
transmission is increasing for 1550nm for Kruse and Kim Model. The maximum data transmission reached to
1.3 km and 1.25km for Kruse and Kim models respectively, for 16-PPM, while reaching to 1.13 and 1.19 km
for Kruse and Kim model when applied NRZ-OOK modulation technique. An approximately occurs in the BER
performance for Al-Naboulsi model compared with the other wavelengths.
Fig (9) BER for 650 nm
Fig (10) BER for 850 nm
Fig (11) BER for 950 nm
Fig (12) BER for 1550 nm
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3.2 The Impact of the transmitted power
It has investigated the effect of transmitter power on BER under fog weather condition. We compare
the performance of the fog models when an NRZ-OOK and 16-PPM used as a modulation format under a PIN
photodiode. Fig. (13) shows BER versus the transmitter power when a distance and visibility are 1 km. If we
consider required 10-10
, when used a 16-PPM modulation format and 650 nm as a carrier signal the transmitter
power about -7dBm and -5dBm, for Kruse and Kim models respectively, while the decrease for Al-Naboulsi
model reached to 3dBm and 6 dBm for convection and advection models. When a NRZ-OOK applied as is
evident in fig. (13). A decrease occurs in the BER leads to increase in the transmitter power reached to 10 dBm
and 13 dBm for Kruse and Kim models, while reached to 20 dBm and 23dBm for Al-Naboulsi model,
convection and advection respectively.
We performed the same calculations also for 850 nm under the same conditions. Fig (14) indicates an
improvement occurs when applied 850 NM as a carrier signal. In this case, notice that for BER 10-10
, a
decreasing occur in the transmitter power, for Kruse and Kim models the transmitter power reached to -30dBm
and -25 dBm respectively; when 16-PPM is applied, while reached to -11 dBm and -8 when NRZ-OOK is
applied. On the other hand, the transmitter power reached to 2dBm and 7dBm for Al-Naboulsi convection and
advection model respectively; when 16-PPM is applied and over 20 dBm for NRZ-OOK is applied. In fig (15)
assume that an FSO communication system operating under 1550 nm, it is clear that, for 16-PPM, the data of
the transmission about -37 dBm for Kruse model and -30 dBm for a Kim model while reaching to -30 dBm. For
NRZ-OOK is applied, the data of the transmission reached to -20 dBm for Kruse model and -14 dBm for Kim
model. It is observed that, the AL-Naboulsi model have the same behavior compared with the wavelength
850nm. An improvement occurs when 1550 nm is used as a carrier wavelength as shown in fig. (16). The
maximum data transmission reached to -70 dBm and -60 dBm for Kruse and Kim models respectively, for 16-
PPM, while reaching to -50 dBm and -42 dBm for Kruse and Kim model when applied NRZ-OOK modulation
technique. Also noticed that, the BER performance of the AL-Naboulsi model have the same behavior for 1550
nm compared with the other near infrared wavelengths (859 nm, 950 nm).
Fig. (13) BER versus Transmitter Power for 650 nm, V=1km, L=1km.
Fig. (14) BER versus Transmitter Power for 850 nm, V=1km, L=1km.
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Fig. (15) BER versus Transmitter Power for 950 nm, V=1km, L=1km.
Fig. (16) BER versus Transmitter Power for 1550 nm, V=1km, L=1km.
V. Conclusion
In this paper, we have investigated a theoretical analysis of the effect of fog on the FSO
communication performance using NRZ-OOK and 16-PPM modulation techniques in the transmitter, and Si
PIN as a receiver with four mathematical models for fog attenuation. The specific attenuation coefficient of the
laser beam through fog weather has a significant effect on the performance of FSO communication systems.
Based on the fog attenuation model and the relation with visibility employed to study the effect of fog on a
receiver signal power, SNR, and BER are investigated. The suitable selected of wavelength has a strong
influence on the attenuation coefficient, which leads to long transmission in free space. When a distance has
increased, this causes a decrease in receiving signal power. The BER characteristics of the NRZ and 16-PPM
modulation techniques under different fog models are studied. The results show that the wavelength 1550nm has
a greater advantages than the other wavelength, therefore, a 1550nm is a more suitable wavelength for FSO
communications compared with the other wavelengths. Furthermore, the theoretical results showed that the
performance of 16 - PPM is far better than the NRZ-OOK, the calculations indicate that Kim and Kruse models
are able to work under long distances. It can be observed that the AL Naboulsi model (Advection and
Convection) insensitive for IR wavelengths, therefore it has the same behavior when the simulation run to
calculate the received signal power, SNR, and BER.
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