Moustafa Hassan - Academia.edu (original) (raw)

Papers by Moustafa Hassan

In this paper, a central power source architecture is applied to a realize power saving wavelengt... more In this paper, a central power source architecture is applied to a realize power saving wavelength division multiplexing passive optical network (WDM-PON). Parametric study isevaluated to extend the transmission distance up to 60 and80 km. Optical launched power is optimized through the parametric study. A full duplex 16 optical channels WDM-PON system are experimentally simulated and analyzed. Successful transmission achieved maximum bit error rate (BER) of 10-13 .A return-to-zero differential phase shift keying (RZ-DPSK) modulation technique isutilized for downlink direction, and then the downlink signal is re-modulated for the uplink direction using intensity modulation technique of on-off keying (OOK) with a data rates of 5 and 1 Gbit/s per channel.

The most significant features of plastic optical fibers (POFs) are investigated, including the ma... more The most significant features of plastic optical fibers (POFs) are investigated, including the main types of POFs, and their properties regarding bandwidth, attenuation, and influence of external parameters are analyzed over wide range of the affecting parameters. This paper has presented the transmission link by using plastic optical fibers that should be verified the following parameters for the POFs system under construction as the following: i) Minimum and maximum transmission distance to be spanned, ii) Transmission data rate, iii) Operating signal wavelengths, iv) Minimum and maximum operating temperature of a system, v) Type and properties of cable to be used, vi) Any required number of passive coupling points, if necessary. This data is the basis for planning the installation from a transmission view point. We have compared our theoretical results of different graded index plastic optical fibers with their simulation results with using perflourinated graded index plastic optical fibers as listed in the conclusion part.

Optical and Quantum Electronics

Optical space communication as a relay satellite system has been employed. The use of laser satel... more Optical space communication as a relay satellite system has been employed. The use of laser satellite communication (SatCom) can alleviate the issues that RF satellite communication encounters. In this study, channel turbulence, additional technologies, intensity modulation direct detection (IM/DD), decoding, and forwarding (DF) are used to evaluate the effectiveness of a proposed laser uplink satellite relay communication model in terms of outage probability (OP) and bit error rate (BER) indicators. This article looks at the necessary channel properties to analyze how operating wavelength affects system performance and compares our results with those of the optical direct link. The performance of the system is investigated by looking at the necessary system parameters, which show the superiority of the proposed system over the optical downlink SatCom, which can improve the required aperture radius up to 10% and the overall system performance up to 57%.

Symmetry, 2021

Both light emitting diode (LED) characteristics for illumination and communication simultaneously... more Both light emitting diode (LED) characteristics for illumination and communication simultaneously have made visible light communication-orthogonal frequency division multiplexing (VLC-OFDM) a strong competitive to radio frequency (RF). In this juncture, to improve signal to noise ratio (SNR) and coverage contour, the wavelet-OFDM is suggested for indoor VLC systems. In this paper, a wavelet VLC-OFDM is proposed for imaging multiple-input multiple-output (MIMO) systems. The proposed wavelet-OFDM is exploited for a hybrid space-frequency domain pre-equalization technique instead of the traditional fast Fourier transform (FFT)-OFDM technique. The Meyer filter is selected and employed in the proposed technique. A comparable achievement is elaborated for several numbers of channels to achieve the enhanced performance in terms of bit rate and coverage contour. In addition, a useful comparison is executed between our wavelet VLC-OFDM and the traditional FFT-OFDM for a hybrid space-frequenc...

In this paper, we propose and evaluate a wavelength division multiplexing passive optical network... more In this paper, we propose and evaluate a wavelength division multiplexing passive optical network (WDM-PON) architecture with a centralized light source (CLS). The use of only one 10 GHz band reject filter at the remote node (RN) allows WDM-PON to have a minimal value of the optical interferometric noise, which is induced by Rayleigh backscattering (RB), in the main lobe of each downstream (DS) optical signal. Utilizing this filter achieves an optical interferometric noise reduction in the upstream (US) direction and the simulation results indicate an enhancement in the performance of a bit error rate (BER) to be 10-11 and in the Q-factor to be above 6.0. Owning to the US signal modulation without extra light source, this architecture successes in power saving and efficient utilization of the wavelength.

Optical and Quantum Electronics, 2021

Moustafa Hussein Aly SAC-OCDMA-FSO Communication System under Different Weather Conditions: Perfo... more Moustafa Hussein Aly SAC-OCDMA-FSO Communication System under Different Weather Conditions: Performance Enhancement Free space optics (FSO) communication is a very recent mechanism. It is mainly needed when physical connection between the transmitter and the receiver is practically impossible and when high bandwidth data transmission is expected. This paper walks through the investigation of the performance of FSO communication adopting spectral amplitude coding optical code division multiple access (SAC-OCDMA) systems at different weather scenarios. The suggested system uses enhanced double weight codes as signature codes by 3 clients, simultaneously. To eliminate multiple access interference and phase induced intensity noise, two different detection schemes are used single photodiode (SPD) and modified-AND subtraction detection schemes. Furthermore, a comparison between PIN and APD detectors is performed. The performance is evaluated through its propagation distance, received power, Q-factor and bit error rate (BER). The obtained numerical results reveal both Q-factor and BER are modified by 30%. Accordingly, the system performance is enhanced by 30%, when using SAC-OCDMA-FSO with SPD detection technique compared with modified-AND subtraction technique.

Alexandria Engineering Journal, 2020

Moustafa Hussein Aly Performance evaluation of 6.4 Tbps dual polarization quadrature phase shift ... more Moustafa Hussein Aly Performance evaluation of 6.4 Tbps dual polarization quadrature phase shift keying Nyquist-WDM superchannel FSO transmission link: Impact of weather conditions This work reports the development of an ultra-high capacity Nyquist-wavelength division multiplexing (WDM) superchannel based free space optics (FSO) transmission link. In the proposed link, 32 independent wavelength channels are multiplexed, each carrying 200 Gbps dual polarization-quadrature phase shift keying (DP-QPSK) data with 60 GHz channel spacing yield net transmission rate of 6.4 Tbps with spectral efficiency of 3.33 bits/s/Hz. The performance of the proposed FSO link has been numerically investigated under the influence of dynamic weather conditions such as clear, haze, rain, and fog conditions. Also, we investigate the BER performance of the proposed link under the influence of beam divergence angle. Further, we compare the proposed FSO link performance with previous works reported in the literature showing the superiority of our proposed link. The simulative investigation of the proposed link was carried out using Optisystem version 14 which is a powerful tool for the development and investigation of optical networks.

Optical and Quantum Electronics, 2020

In this paper, a cascaded fiber Bragg grating (FBG) system is proposed to reduce the dispersion i... more In this paper, a cascaded fiber Bragg grating (FBG) system is proposed to reduce the dispersion in the optical signal in single mode optical fibers. This consequently enhances the system performance, which is evaluated by the bit error rate (BER) and quality factor (Q-factor). The proposed model consists of four uniform cascaded FBGs connected at the transmitter to get narrow linewidth, ??, of the optical signal, which is a major cause of the delay. The Optisystem7 is used to simulate the proposed model in a WDM system with and without the model for distance 200 km. The system parameters are investigated showing an enhanced performance with 12%, including eye diagram, Q-factor and BER. A 10?6-10?10 BER is achieved with a quality factor in the range 7-14, including the effects of fiber length, input power and FBG length.

Applied Optics, 2020

In this paper, we introduce the idea of using adaptive hybrid modulation techniques to overcome c... more In this paper, we introduce the idea of using adaptive hybrid modulation techniques to overcome channel fading effects on visible light communication (VLC) systems. A hybrid M -ary quadrature-amplitude modulation ( M Q A M ) and multipulse pulse-position modulation (MPPM) technique is considered due to its ability to make gradual changes in spectral efficiency to cope with channel effects. First, the Zemax optics studio simulator is used to simulate dynamic VLC channels. The results of Zemax show that Nakagami and log-normal distributions give the best fitting for simulation results. The performance of M Q A M –MPPM is analytically investigated for both Nakagami and log-normal channels, where we obtain closed-form expressions for the average bit-error rate (BER). The optimization problem of evaluating the hybrid modulation technique settings that lead to the highest spectral efficiency under a specific channel status and constraint of outage probability is formulated and solved usin...

Applied Sciences, 2018

Free-space optical (FSO) communication systems have attracted considerable research interest owin... more Free-space optical (FSO) communication systems have attracted considerable research interest owing to its high transmission rates and its efficient solution for the last mile problem. Atmospheric turbulence degrades the performance of FSO systems. To estimate the received signal, Channel State Information (CSI) or blind detection is used. The blind detection estimates the received signal without the need for pilot signals which reduce the throughput and increase the complexity of the signal. In this paper, we have proposed a relay technique which utilizes the blind detection method for FSO communications. This proposed technique would improve the performance of the FSO system compared to the direct link method. It is observed that the proposed method achieves a signal-to-noise ratio (SNR) close to the SNR reported by CSI method maintaining the same average bit error rate, provided that only a small observation window is employed. Moreover, Monte Carlo simulation results are further ...

Optics express, Jan 6, 2018

Ultraviolet (UV) communication overcomes pointing and tracking errors and is superior to other mo... more Ultraviolet (UV) communication overcomes pointing and tracking errors and is superior to other modern optical wireless communication technologies at short range. Using effective wavelengths from 200 to 280 nm, enables the non-line-of-sight (NLOS) outdoor UV communication in the presence of strong molecular and aerosol scattering. Because of these characteristics, solar blind NLOS UV communications offers broad coverage and high security. In this paper, NLOS UV communication is considered with decode and forward (DF) relays in the presence of log-normal (LN) channels using the best relay selection technique according to the channel state information (CSI). Then the outage probability of the multi-relay UV system is discussed for the proposed model. Simulation results verify the effectiveness of our employed analytical model. The outage probability for both serial and cooperative relays is compared with a different number of relays. Numerical simulations are further presented for many...

Optics Communications, 2016

A modification to the Asymmetrically-Clipped Optical Orthogonal Frequency-Division Multiplexing (... more A modification to the Asymmetrically-Clipped Optical Orthogonal Frequency-Division Multiplexing (ACO-OFDM) technique is proposed through unipolar encoding. A performance analysis of the Bit Error Rate (BER) is developed and Monte Carlo simulations are carried out to verify the analysis. Results are compared to that of the corresponding ACO-OFDM system under the same bit energy and transmission rate; an improvement of 1 dB is obtained at a BER of 10-4. In addition, the performance of the proposed system in the presence of atmospheric turbulence is investigated using single-input multiple-output (SIMO) configuration and its performance under that environment is compared to that of ACO-OFDM. Energy improvements of 4 dB and 2.2 dB are obtained at a BER of 10-4 for SIMO systems of 1 and 2 photodetectors at the receiver for the case of strong turbulence, respectively.

2016 Sixth International Conference on Digital Information Processing and Communications (ICDIPC), 2016

Moustafa Hussein Aly Performance Analysis of FSO Communication System: Effects of Fog, Rain and H... more Moustafa Hussein Aly Performance Analysis of FSO Communication System: Effects of Fog, Rain and Humidity Free Space Optics (FSO) is one of the most promising new access technologies. FSO provides the transmission of data with unlimited bandwidth. The atmospheric attenuation is caused by two main factors absorption and scattering. This paper investigates a performance study of free space optics channel for variable wavelengths 850 nm, 950 nm and 1550 nm at distance range of 1 km. The simulation reports minimum BER for NRZ-OOK modulation technique at different receiver diameters in presence of fog, rain and humidity attenuation. The obtained results reflect the system improvement achieving minimum BER and maximum received power that can be detected at distance 1 km.

In this paper, an all optical orthogonal frequency division multiplexing (OFDM) is proposed for a... more In this paper, an all optical orthogonal frequency division multiplexing (OFDM) is proposed for achieving better performance compared with single carrier communications and eliminating intersymbol interference in optical wireless communications. The paper shows the overall architecture along with the design considerations should be followed for parameters calculation. Analytical evaluation of the system in terms of probability of error is carried out in a non-directed (diffused) wireless optical channel. The paper confirms with simulation that the proposed system shows promising results for a high speed optical wireless channel.

Multimode fibers are characterized by multipath propagation of optical signals which leads to sev... more Multimode fibers are characterized by multipath propagation of optical signals which leads to severe Inter Symbol Interference (ISI) at the output of the fiber. In this work, approaches based on the spread spectrum (SS) techniques are proposed to overcome this drawback. An optimization algorithm is developed and appropriate software is employed to apply the proposed methodology on a specific multimode fiber. Extensive simulation results are produced and are presented herein. The numerical results have shown that the order of magnitude of the maximum data rate, R, supported at different CDMA gains, in order to achieve a bit error rate (BER) value smaller or equal to a convergent point, is related to the length of the multimode fiber, L, and the CDMA technique used. The Hybrid CDMA type direct sequence/frequency hopping (DS/FH) is applied to eliminate the disadvantage of DS which is the near-far effect (different power levels of users at optical fiber input).

Based on a detailed simulation analysis in optical burst switching (OBS) networks, a proposed new... more Based on a detailed simulation analysis in optical burst switching (OBS) networks, a proposed new routing protocol metric is driven based on the Burst loss ratio (BLR). It takes into account many optical parameters in its dependency as number of channels, load and link bandwidth. Depending on this new metric, an unequal load balance routing technique is proposed. It is shown that, in some examples, more than 50 % of the drop rate is avoided when using load balance routing rather than single best path routing.

Moustafa Hussein Aly Effect of Link Bandwidth, Number of Channels and Traffic Load on Designing O... more Moustafa Hussein Aly Effect of Link Bandwidth, Number of Channels and Traffic Load on Designing Optical Burst Switching Networks A detailed simulation is carried out for analysis of various optical parameters effect on burst loss ratio (BLR) in optical burst switching (OBS) networks. Effects of link bandwidth, number of channels and traffic load are studied. The obtained results show that one parameter can compensate another to reach the same BLR. For example, one can decrease the link bandwidth by 50% and increase the number of channels while maintaining the same BLR. This leads to have many OBS networks designs giving same performance.

2009 6th International Symposium on High Capacity Optical Networks and Enabling Technologies (HONET), 2009

2009 IFIP International Conference on Wireless and Optical Communications Networks, 2009

Based on an extensive simulation analyses on various optical parameters effect on burst loss rati... more Based on an extensive simulation analyses on various optical parameters effect on burst loss ratio (BLR) for optical burst switching (OBS) networks. A comparison between routing decision based on standard open shortest path first (OSPF) routing protocol and a proposed new OSPF metric is performed. The proposed new OSPF metric takes into account optical parameters in its dependency as number of channels, load and link bandwidth. The result shows better routing decisions leading to better BLR and utilization for OBS networks. Index Terms-Optical burst switching, Routing metric, optical routing, open shortest path first (OSPF), fiber delay line, traffic load, channel bandwidth, number of channels.