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 Wireless Communications & Networks (adaptation by V K Chaubey)(Pearson Education, 2009) Chaubey, V.K.Item Analysis of Optical WDM Network Topologies with Application of LRWC Under symmetric Erlang - C Traffic(Springer, 2008) Chaubey, V.K.This paper analyses an Optical WDM network model with application of Limited Range Wavelength Converters for online routing with a wavelength assignment scheme under symmetric Erlang-C traffic. Distinct wavelengths have been assigned to short and long hop connections by wavelength conversion besides attempt to reserve an identical wavelength across all nodes. Probabilistic model for traffic has been developed employing both ring and star topology networks. A mathematical model has been further devised and its call blocking probability has been enunciated. Compared performance analysis of both topologies has been presented with an investigation on collective impacts of various traffic parameters on transmission.Item High Speed Resonant Tunneling Diode Based on GaN & GaAs: A Modelling & Simulation Approach(CRC, 2008) Chaubey, V.K.The investigation of tunneling of particles through potential barriers in semiconductor quantum wells has recently attracted much attention. Special focus is laid on resonant tunneling structures because of its importance in the field of nanoscience and technology and its potential applications in very high speed functionality devices and circuits. Among the numerous nanoelectronic devices proposed and demonstrated, the III-V based RTD is perhaps the most promising candidate for digital circuit applications due to its negative differential resistance (NDR) characteristic, structural simplicity, inherent high speed, flexible design freedom, relative ease of fabrication and versatile circuit functionality. There is a good practical reason to believe that these RTDs may be the next device based on quantum confined heterostructures to make the transition from the world of research into practical application. In this work, we have worked with two materials GaAs and GaN which are most useful for building next generation quantum devices. Apart from studying the tunneling as an electrical phenomenon, we have investigated how light of different energies affect the tunneling process in the two compound semiconductor materials chosen. Tunneling Current variation with different energies of barriers, barrier heights and electron energies has been studied. Eigen states have been found for the barriers. The effect of bias across tunneling has been reported. Precise control of tunneling using gate control (RTT) or Base control (for bipolar device) is presented with an optical control. The change in refractive index of a semiconductor on interaction with photon is exploited to derive the relation between the band gap of a semiconductor and incident light. A Bandgap variation ultimately leads to re-alignment of quantum states hence impacting the tunneling mechanism.Item Estimation of Optimal Buffering parameters for dynamic traffic intensity and its Architectures(2005) Chaubey, V.K.In this paper, we have undertaken the mathematical formulation for determining the required buffering time based on the traffic intensity on an all-optical network. The effect of design parameters on optical network containing proper buffer and control circuitry has been evaluated. Some of the buffering architectures have been suggested to provide different buffering times as governed by the diurnal traffic requirementsItem Analysis of a CSMA/CA Optical Network with Application of Optical Buffers (FDLs) for Online Routing(IEEE, 2008-01) Chaubey, V.K.This paper proposes a new algorithm in an optical network using online routing with the application of optical buffers comprising of delay-lines (FDLs). The model for the algorithm has been theoretically developed and the corresponding call connection probability has been calculated. The limitation on the amount of delay permitted per packet has been addressed by limiting the number of delay-lines used in switch fabric of the network. The algorithm proposed is deterministic. It employs the concept of online routing to implement `look ahead' characteristics and thus aims to design an intelligent optical network. Keywords: FDL; TDM; AON; OPS; Look ahead; Deterministic delay-line transmission algorithm; Call connection probabilityItem Mixedmode circuit simulation of silicon and germanium nanowire MOSFETs - A comparative study(IEEE, 2011) Chaubey, V.K.Nanowire MOSFETs have been recognized as one of the possible choices to continue the scaling of CMOS beyond conventional scaling limits. In present study we study various aspects of device characteristics and Mixedmode circuit behavior of Silicon and Germanium Nanowire MOSFETs. The various parameters determining the behavior of device in the analog/digital circuits is studied and compared for Nanowire MOSFET with Si and Ge as channel material. Important parameters such as transconductance, output conductance, Ion/Ioff ratio and short channel parameters have been extracted and compared for Silicon and Germanium. The Mixed mode circuit simulation has been done for Inverter (VTC and transient analysis) and 3 stage Ring Oscillator (transient analysis). Results of these simulations give insights into the in-circuit behavior of these future generation devices.Item Design and Performance Analysis of Deflection Routing Based Intelligent Optical Burst Switched (OBS) Network(IEEE, 2011) Chaubey, V.K.Optical burst switching (OBS) is a promising switching technology for realization of terabit optical network. However, the lack of optical processing capability results in increased blocking probability and limits the network performance. Efficient contention resolution is therefore necessary. Optical burst-switched networks are usually implemented using efficient contention resolution protocols like deflection routing, however deflection routing approach resolves the congestion by exploiting alternate available paths and utilizes the resources effectively. If contention is resolved by traditional deflection routing then there is no guarantee that the control packet will be able to reserve all the wavelengths successfully up to the destination on the alternate path, especially in a high traffic load situation. The present paper proposes a scheme of deflection routing by assigning suitable wavelengths to various routed paths based on respective traffic to be routed. A mathematical model for the same has been developed and the network performance has been simulated using MATLAB to establish congestion performance of the proposed scheme.Item Stimulated Raman Scattering Induced Power Penalty Analysis for Optical WDM Network(IEEE, 2011) Chaubey, V.K.In optical wavelength-division multiplexing (WDM) systems, if the number of users is increased; the crosstalk becomes more severe due to imperfections in the passive optical filters (gratings) and nonlinear effects due to the power increasing in the optical fiber. In this research paper we have considered Stimulated Raman Scattering (SRS) as the source of nonlinear degradation in the multichannel system. The power penalty induced by Raman crosstalk has been evaluated for both wavelength division multiplexed and dense wavelength division multiplexed networks. It is observed that the penalty is higher at higher input power, higher number of channels and higher bit rates used for transmission.Item Bluetooth based e-Tutor system for effective knowledge transfer(IJAER, 2011) Chaubey, V.K.