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Yayın Comparative performance evaluation of VLC, LTE and WLAN technologies in indoor environments(IEEE, 2021-05-24) Zeshan, Arooba; Karbalayghareh, Mehdi; Miramirkhani, Farshad; Uysal, Murat; Baykaş, TunçerRecent years have seen an exponential rise in the demand for indoor wireless connections that have driven future generation networks to aim for higher data rates with extended coverage and affordable rates. The two most prominent technologies for providing indoor wireless connections, WLAN and LTE, have their limitations and they can not coexist in a single band to form heterogeneous networks (HetNets). Visible light communication (VLC) has seen rapid growth in recent years as it has the capability to seamlessly merge with the existing technologies and provide wireless connections with high data rates. VLC based hybrid indoor network effectively combines the preferences of an end-user with the practicality of implementation. In this work, we investigate specific VLC/WLAN and VLC/LTE hybrid scenarios to perform a detailed analysis on the effect of user mobility on the performance of the system and how the performance of the network (in terms of throughput) can be maximized. The study aims to show how different technologies complement each other in the best and even the worst-case scenarios.Yayın A path loss model for link budget analysis of indoor visible light communications(Istanbul Univ-Cerrahpasa, 2021-05) Miramirkhani, FarshadIn the context of beyond 5G indoor communication systems, visible light communications (VLC) has emerged as a viable supplement for existing radio frequency based systems and as an enabler for high data rate communications. However, the existing indoor VLC systems are limited by detrimental outages caused by fluctuations in the VLC channel gain because of user mobility. In this study, we proposed a tractable path loss model for indoor VLC that reflects the effect of room size and coating material of surfaces. We performed an extensive advanced ray tracing simulation to obtain the channel impulse responses within a room and presented a path loss model as a function of distance, room size, and coating material through curve fitting. In addition, path loss parameters such as the path loss exponent and the standard deviation of the shadowing component were determined. The simulation results indicate that path loss is a linear function of distance, path loss exponent is a function of room size and coating material, and shadowing follows a log normal distribution.Yayın A path loss model for vehicle-to-vehicle visible light communications(Institute of Electrical and Electronics Engineers Inc., 2019-07) Eldeeb, Hossien Badr; Miramirkhani, Farshad; Uysal, MuratThe increasing adoption of LEDs in exterior automotive lighting makes visible light communication (VLC) a natural solution for vehicular networking. In this paper, we consider a vehicle-to-vehicle link and propose a path loss expression as a function of distance and different weather conditions. We conduct ray tracing simulations and verify the accuracy of proposed expression. We further use this expression to derive the achievable transmission distance for a targeted data rate while satisfying a given value of bit error rate. Numerical results are presented to demonstrate the achievable distances for single and dual photodetector deployment cases.Yayın Intelligent health monitoring in 6G networks: machine learning-enhanced VLC-based medical body sensor networks(MDPI, 2025-04-30) Antaki, Bilal; Dalloul, Ahmed Hany; Miramirkhani, FarshadRecent advances in Artificial Intelligence (AI)-driven wireless communication demand innovative Sixth Generation (6G) solutions, particularly in hospitals where reliability and secure communication are crucial. Visible Light Communication (VLC) leverages existing lighting systems to deliver high data rates while mitigating electromagnetic interference. However, VLC systems in medical settings face fluctuating signal strength and dynamic channel conditions due to patient movement, necessitating advanced optimization techniques. This paper employs a site-specific ray tracing technique in Medical Body Sensor Networks (MBSNs) channel modeling within hospital scenarios to derive channel impulse responses (CIRs) and model path loss (PL) and Root Mean Square (RMS) delay spread in two distinct hospital settings. In the first section, we evaluate Machine Learning (ML)-based adaptive modulation in VLC-enabled MBSNs and introduce a Q-learning technique enabling real-time adaptation without prior environmental knowledge. In the second section, we propose a Long Short Term Memory (LSTM) based approach to estimate PL and RMS delay spread in dynamic hospital environments. The Q-learning method consistently achieved the target symbol error rate (SER), though spectral efficiency (SE) was sometimes lower than optimal due to quantization limits and a cautious approach near the SER threshold. For LSTM-based channel estimation algorithm, simulation studies show that in the Intensive Care Unit (ICU) ward scenario, D1 has the highest Root Mean Squared Error (RMSE) for estimated path loss (1.6797 dB) and RMS delay spread (1.0567 ns), whereas in the Family-Type Patient Rooms (FTPR) scenario, D3 exhibits the highest RMSE for estimated path loss (1.0652 dB) and RMS delay spread (0.7657 ns).Yayın IEEE 802.11BB reference channel models for light communications(IEEE, 2023-12-01) Miramirkhani, Farshad; Baykaş, Tunçer; Elamassie, Mohammed; Uysal, MuratIncreasing industrial attention to visible light communications (VLC) technology led the IEEE 802.11 to establish the task group 802.11bb 'Light Communications' (LC) for the development of a VLC standard. As a part of the standard development process, the development of realistic channel models according to possible use cases is of critical importance for physical layer system design. This article presents the reference channel models for the mandatory usage models adopted by IEEE 802.11bb for the evaluation of system proposals. The use cases include industrial, medical, enterprise, and residential scenarios. Channel impulse responses and corresponding frequency responses are obtained for each use case using a ray tracing approach based on realistic specifications for transmitters and receivers, and optical characterization of the environment.
