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ELAMASSIE, Mohammed

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Mohammed

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ELAMASSIE
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Now showing 1 - 10 of 34
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    Effect of sea waves on vertical underwater visible light communication links
    (IEEE, 2023-04) Elamassie, Mohammed; Sait, S. M.; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat
    Underwater visible light communication (VLC) has been proposed to deal with emerging high bandwidth underwater applications. Initial research works on underwater VLC are based on the assumption that both transmitter and receiver are submerged, creating a horizontal link. In most of the vertical communication links, one of the transceiver nodes takes the form of a buoy and requires taking into the effect of the sea surface, which is inherently unsteady due to wind and waves. In this article, we consider a vertical underwater VLC link where the transmitter is in the form of a buoy at the sea surface, and the receiver is a submerged node at a certain depth. We assume sinusoidal waves and consider the fact that the buoy will fluctuate and oscillate, during drifting up and down, around its vertical axis. This effectively results in a 3-D displacement at the suspended transmitter. Building upon these assumptions of practical relevance, we propose an aggregate channel model, which includes a random path loss due to periodic changes of the transmission distance and a fading term induced by pointing errors with periodic changes of relative movement. Based on the proposed statistical model, we derive closed-form expressions for the exact and asymptotic bit error ratio and investigate the achievable diversity orders. We further present numerical results to confirm the analytical findings.
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    Experimental characterization of multi-hop vehicular VLC systems
    (IEEE, 2021) Mohamed, Bassam Aly Abdelrahman; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; Mohamed, Bassam Aly Abdelrahman
    In vehicular visible light communication (VLC), the reliable communication distance may be relatively short due to its dependence on many factors including the weather condition. This necessitates the use of relay-assisted systems to extend the transmission range. In this paper, we investigate experimentally the performance of vehicular multi-hop VLC systems in outdoor environments. Particularly, we first examine the effect of ambient noise on signal-to-noise ratio (SNR) during a whole day. Then, we conduct two multi-hop experiments, i.e., one at daytime and one at nighttime. We measure the bit error rate (BER) for each individual hop and then obtain the overall performance of the multi-hop system. We further compare experimental BER with theoretical BER to confirm our results.
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    Performance investigation of streetlight-to-vehicle visible light communication
    (IEEE, 2023) Eldeeb, Hossıen Badr; Elamassie, Mohammed; Muhaidat, S.; Uysal, Murat; Ho, T. D.; Electrical & Electronics Engineering; ELDEEB, Hossien Badr Hossien; ELAMASSIE, Mohammed; UYSAL, Murat
    This paper investigates streetlight-to-vehicle visible light communication (VLC) system performance for outdoor broadcasting applications. We adopt streetlight lamps as optical internet-of-thing (IoT) devices broadcasting internet services and safety messages to road vehicles. With their asymmetrical radiation patterns, Streetlight antennas are exceedingly different from indoor lighting modules, which deploy ceiling luminaries with ideal Lambertian ones. Therefore, a realistic channel modelling for streetlight-to-vehicle VLC system should be deployed for precise performance insights. We consider a streetlight-to-vehicle VLC system in a two-lane road with multiple light poles uniformly distributed on both sides. Based on that, we investigate the system performance of the streetlight-to-vehicle VLC system in terms of the bit-error-rate (BER) and outage distance and explore the effect of different transceivers and system parameters on the performance. These consider the transmission modulation order, receiver size, height of the streetlight poles, and their corresponding intermediate distances.
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    Vehicular VLC system with selection combining
    (IEEE, 2022-11) Mohamed, Bassam Aly Abdelrahman; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat; Mohamed, Bassam Aly Abdelrahman
    The availability of LED-based headlights and taillights makes possible the use of visible light communication (VLC) as a wireless access technology for vehicle-to-vehicle (V2V) communications. A critical concern to establish a reliable VLC link between two moving vehicles is the number of photodetectors and their locations on the destination vehicle. In this paper, we experimentally investigate the usage of dual photodetectors for a vehicular VLC system with selection combining to enhance signal reception in mobile conditions. We measure the electrical receive signal-to-noise ratio (SNR) for each individual photodetector as well as at the output of selection combiner in two different tracks involving straight and curved roads. Through data fitting to experimental data, we obtain a probability density function (PDF) to describe the instantaneous SNR. Based on the PDF, we derive a closed-form expression for the average bit error rate (BER) in the form of a finite summation and compare it with the measurements.
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    Vehicle-to-infrastructure visible light communications: Channel modelling and capacity calculations
    (IEEE, 2020) Eldeeb, Hossıen Badr; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat; ELDEEB, Hossien Badr Hossien
    In this paper, we investigate the performance of a visible light communication (VLC) system for vehicle-to-infrastructure (V2I) connectivity. Two headlamps of the vehicle serve as wireless transmitters while photodetectors located within the traffic light pole act as wireless receivers. We use non-sequential ray-tracing approach to obtain optical channel impulse responses (CIRs) for the V2I scenario under consideration assuming different positions of the vehicle within the road. Based on the CIRs to model propagation environment as well as the effects of LED non-linear characteristics, we calculate the achievable signal-to-noise ratio and achievable data rates for VLC-based V2I systems.
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    Vehicular visible light communication with low beam transmitters in the presence of vertical oscillation
    (IEEE, 2023-08) Mohamed, Bassam Aly Abdelrahman; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat; Mohamed, Bassam Aly Abdelrahman
    The availability of light-emitting diodes (LEDs) in vehicle exteriors makes possible the use of visible light communication (VLC) as a vehicle-to-vehicle (V2V) wireless connectivity solution. While there has been a growing literature on vehicular VLC, the existing works inherently assume the deployment of regular passenger vehicles. In this paper, we consider the use of VLC for vehicular connectivity between heavy vehicles such as trucks. We assume that low beam headlights are used as transmitters. Due to the nature and function of vehicular low beam lighting, the upward distribution of lighting is fundamentally different from its downward distribution. Hence, the vertical displacement (i.e., the height difference between transmitter and receiver) and the vertical oscillation experienced by heavy vehicles might significantly impact the VLC link. Based on experimental measurements, we first propose an accurate path loss model that takes into account the effect of vertical displacement and oscillation. Then, we derive a bit error rate (BER) expression for VLC-based truck-to-truck communication system and investigate the effect of several system and channel parameters on the performance. In an attempt to mitigate the degrading effects of the vertical oscillation, we further investigate the proper selection of photodetector location to minimize the error rate performance.
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    An experimental study of underwater visible light communication
    (IEEE, 2022) Yıldız, Samet; Baǧlıca, İbrahim; Kebapçı, B.; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; UYSAL, Murat; ELAMASSIE, Mohammed; Yıldız, Samet; Baǧlıca, İbrahim
    Visible light communication (VLC) has emerged as a powerful high-data-rate alternative to conventional underwater acoustic technology for short and medium link distances. In this paper, we develop an experimental underwater VLC platform and present some initial performance results. Our set-up uses prerecorded voltage levels fed in the arbitrary waveform generator (AWG) at the transmitter side while an oscilloscope is used to measure the received electrical signal after photodetection. To speed up debugging and troubleshooting, both transmitter and receiver sides are connected to a controller PC. The test instruments are controlled via Standard Commands for Programmable Instruments (SCPI) commands executed by this controller computer with a Python code. Using this set-up, we demonstrate the successful transmission of 8-PAM symbols over an 8-meter-long underwater tank.
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    Statistical characterization of FSO-based airborne backhaul links
    (IEEE, 2023) Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat
    Backhaul solutions with large capacity and global coverage are of great importance for 6G wireless communication networks. With its ultra-large bandwidth and immunity to electromagnetic interference, free-space optical (FSO) communication has stood out as a major connectivity solution for UAV-to-UAV and UAV-to-ground links. While the performance of horizontal terrestrial FSO links is mainly limited by atmospheric-turbulence-induced fading, geometrical and atmospheric losses dominate the link budget of an airborne link between a high-altitude fixed-wing UAV and a ground station. Since the fixed-wing UAV continuously moves, the transmission distance between it and the ground station changes, causing both atmospheric and geometric losses to change, which results in the fading effect. In this paper, we statistically characterize this aggregate channel coefficient. First, we derive a probability density function for the channel coefficient; then, we obtain an expression for the instantaneous received signal-to-noise ratio (SNR). We validate our derived expressions through numerical calculations.
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    Bit-error-rate performance of an underwater wireless optical link under misalignment and turbulence effects
    (IEEE, 2022) Ijeh, I. C.; Khalighi, M. A.; Elamassie, Mohammed; Hranilovic, S.; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat
    Underwater wireless optical communication (UWOC) links are highly susceptible to the degrading effects of oceanic turbulence and beam misalignment. In this paper, considering a silicon photo-multiplier at the receiver, we evaluate the link average bit-error rate (BER) performance, where an analytical expression is derived for its calculation, validated further by means of numerical simulations. We further investigate the impact of different system parameters on the link average BER.
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    Finite-SNR diversity gain analysis of FSO systems over gamma-gamma fading channels with pointing errors
    (IEEE, 2021-06) Elamassie, Mohammed; Sait, S. M.; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat
    Free space optical (FSO) communication systems are subject to turbulence-induced fading as a result of fluctuations in the refractive index. Gamma-Gamma (GG) distribution is commonly used in the literature to characterize moderate-to-strong turbulence conditions. The performance of FSO systems is further degraded by pointing error-induced fading as a result of building sways. While the asymptotic analysis presented in earlier works is important to understand the maximum diversity gains of FSO systems attainable over fading channels, such gains might not be available in practical range of signal-to-noise ratio (SNR). Furthermore, different systems with the same asymptotic slope may have different slopes in the range of finite SNR values. In this paper, we consider a multiple-input multiple-output (MIMO) FSO system with intensity modulation and direct detection (IM/DD). We derive approximate expression for the finite-SNR diversity order over GG turbulence channels in the presence of pointing errors. We also investigate convergence speed to full diversity. We provide numerical results to demonstrate the accuracy of our derivations and corroborate on our analytical findings.