Department of Electrical and Electronics Engineering
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Item IRS-aided UOWC network for IoUT applications: performance analysis(IEEE, 2025-08) Chaubey, V.K.; Joshi, SandeepThis paper investigates the inclusion of intelligent reflecting surfaces (IRSs) in data acquisition in underwater optical wireless communication (UOWC) systems for the internet of underwater things (IoUT). The paper proposes a medium access control layered protocol that employs slotted ALOHA (S-ALOHA) and code-combining (C-C) to support reliable communication between multiple underwater sensors and a receiver. A buoy-mounted IRS is considered to improve signal reliability and mitigate underwater attenuation, turbulence, and beam misalignment. The underwater communication channel is modeled using the exponentiated Weibull distribution to propose a framework for the outage analysis of both uniformly and randomly distributed sensors with C-C. The throughput performance of the proposed IoUT network for S-ALOHA and C-C demonstrates that system performance is well controlled by the reflecting elements, transmission distance, and fading parameters. Simulation results claim that the IRS-assisted UOWC significantly improves throughput and reduces outage probability under challenging underwater conditions.Item Outage Analysis of IRS-Assisted Dual-Hop Mixed RF-UWOC Network(IEEE, 2023-06) Joshi, Sandeep; Chaubey, Vinod KumarIn this work, we derive the outage analysis of an intelligent reflecting surface (IRS)-assisted dual-hop mixed radio frequency (RF)-underwater wireless optical communication (UWOC) network. For diverse underwater operations such as surveillance, excursions, and climate monitoring, UWOC is a promising solution for transferring high-speed information. IRS is a revolutionary low-cost technique to improve the received signal strength and system performance. The use of IRS is advantageous in improving wireless communication over long distances by providing a line-of-sight path and making it reliable. We investigate a communication scenario where a source located underwater transmits signals to the relay using an underwater wireless optical link, which, assisted by the IRS, provides an alternate path to the receiver through an RF link. We consider generalized κ-µ fading for the relay-IRS and IRS-receiver RF communication links, mixed intensity-modulation direct detection (IM-DD) with exponential generalized Gamma distribution for the source-relay UWOC link.Item Outage Analysis of an IRS-Assisted 5G and Beyond Wireless Communications System(IEEE, 2023-06) Joshi, Sandeep; Chaubey, Vinod KumarIn this work, we present an outage analysis of an intelligent reflecting surface (IRS)-assisted wireless communications system considering direct and indirect communication links between the transmitter and the receiver. We derive the probability density function and cumulative distribution function for the combined communication link between the transmitter, IRS, and the receiver. Furthermore, we derive the closed-form expressions for the outage probability, considering the direct link between the transmitter and the receiver as Nakagami-m faded, and the indirect communication link via IRS is considered to be under Rician fading. The analytical results are verified by simulations and give insight into modeling and analysis of N element IRS-assisted wireless communications system. We observe that the performance of the considered IRS- assisted wireless communications system significantly improves with an increase in the number of reflecting elements.Item Channel Estimation-Based Rate Maximization for IRS-Aided UAV Wireless Communication Systems(IEEE, 2024-08) Joshi, Sandeep; Chaubey, Vinod KumarIn this paper, we provide a channel estimation-based optimization technique for maximizing the weighted sum rate (WSR) of an intelligent reflecting surface (IRS)-aided unmanned aerial vehicle (UAV). The model considers an IRS mounted on a UAV to predict the channel between the multi-input base station (BS) for the multi-user system using mobile IRS-aided wireless channels. We optimize the UAV position and then employ a compressive sensing-based technique that exploits the sparsity of the wireless channel, specifically, we utilize the Bayesian iterative group approximate message passing (BIG-AMP) algorithm. The strategy involves mobile IRS for efficient message passing and estimation of the channel state information between the BS and users. Using these channel estimates, we maximize the WSR for all the users by optimizing the precoding matrix at the BS and also the phase matrix at the mobile IRS.Item Opportunistic Scheduling in IRS-Aided UAV Multi-User Wireless Communication Systems: Modeling and Analysis(IEEE, 2024-11) Joshi, Sandeep; Chaubey, Vinod KumarIn this paper, we present the performance analysis of an opportunistic scheduling-based intelligent reflecting surface (IRS)-aided unmanned aerial vehicle (UAV) multi-user wireless communication system. We consider an IRS mounted on a UAV and the communication links between transmitter and receiver to be Rician faded. The considered IRS-aided UAV communication system performs opportunistic scheduling for user selection and transmission, assuming the practical limitation of outdated channel state information (CSI). We provide an analytical framework for the IRS-aided UAV wireless communication system and derive expressions for outage probability, asymptotic outage probability, ergodic capacity, effective capacity, and symbol error rate (SER) considering M-ary phase shift keying modulation. We show the performance variations with the CSI parameter, the number of reflecting elements, the Rician factor, and the delay constraint. We observe that a lower delay constraint value results in higher effective capacity. Furthermore, the analytical results are verified through system simulations.