Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.Naik, R.P.

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    Experimental studies on realization of underwater optical communication link
    (Institute of Electrical and Electronics Engineers Inc., 2017) Kumar, A.; Naik, R.P.; Shripathi Acharya, U.S.
    A comprehensive experimental setup for underwater optical communication (UWOC) is proposed in this paper. This UWOC real time setup provides an underwater communication link (using sea water) which is able to achieve reliable communication within a 3m long range. The minimum transmit power requirement for communication at a Bit Error Rate (BER) of 10-3 in the presence of turbulence (generated within the experimental setup) and stationary water has been determined. Two UWOC setups are implemented, first setup is designed by utilizing opaque PVC pipes and the second setup is designed by aquarium tank. These setups are used in conjunction with water jets and rotating plates (to bring about obstruction in the line of sight) to replicate conditions of underwater turbulence and blockage. This allows a realistic reconstruction of light wave propagation under the surface of the sea. Our proposed setup provides a platform for experimental studies on UWOC and convey the idea and it is helpful in the analysis of real time power budget required by the system. It provides a foundation for more comprehensive experimental platforms which will be designed to accurately mimic various disruptions that can be encountered with UWOC. The proposed UWOC helps in the development of constructive techniques that can mitigate the effects of the channel induced errors and ensure error free communication. © 2017 IEEE.
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    BER Performance Analysis of Optical Wireless Communication System over Weak and Strong Underwater Turbulence Channels
    (Springer Science and Business Media Deutschland GmbH, 2023) Naik, R.P.; Shripathi Acharya, U.S.; Bhargava Kumar, L.B.; Krishnan, K.; Chung, W.-Y.
    In this paper, we have investigated the performance of an underwater wireless optical communication (UWOC) link employing single-input and single-output (SISO) and selection combining (SC) as receiver diversity for varying link-ranges. As the the link-range increases, then strength of turbulence between the underwater optical entities also increases. It is assumed that the distribution of light propagation in weak and strong turbulence UWOC channel as log-normal (LN) and gamma-gamma (GG) density functions, respectively. The analytical bit error rate (BER) equations of on–off keying modulated UWOC link have been derived for SISO and SC receiver diversity using hyperbolic tangent distribution for LN and power series for GG density functions. The analytical BER results are validated with the Monte Carlo simulations. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Outage Probability Analysis of Variable and Fixed Gain Relay-Assisted Dual-Hop RF-FSO Links Using Space–time Block Code Users
    (Springer Science and Business Media Deutschland GmbH, 2023) Naik, R.P.; Bhargava Kumar, L.B.; Krishnan, K.; Chung, W.-Y.
    In this paper, we have implemented an analytical study on a relay-assisted dual-hop system using fixed and variable gains for the radio-frequency (RF) and free-space optical communication (FSO). RF and FSO links are realized using the Rayleigh and Malaga distribution functions. Simulation results shows that pointing errors become severe, system performance deteriorates, and conjointly that the RF users exploiting space–time block coding (STBC) will enhance the performance of the end-to-end system. Outage probability of the end-to-end communication link operated with the STBC using the variable and fixed gain system implemented and plotted with respect to average SNR. From the obtained results, fixed gain relay-based communication link performs better efficient than the variable gain relay system. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Performance of Orthogonal and Non-Orthogonal Space Time Block Code Through the Underwater Wireless Optical Channels
    (IEEE Computer Society, 2023) Naik, R.P.; Mans, R.; Shripathi Acharya, U.; Savidhan Shetty, C.S.
    Multiple input multiple output (MIMO) schemes have been integrated with the space-time (ST) codes to enhance the reliability of information transfer across the wireless channel. Due to their rich algebraic structure, space time block codes (STBCs) such as orthogonal STBCs (OSTBC), quasi-orthogonal STBC (QOSTBC), and non-orthogonal STBCs (NOSTBC), offer efficient implementation of a reliable communication system. The underwater wireless optical communication (UWOC) channel is perturbed by the weak turbulence and fading (referred as scintillation), and shares many properties with a wireless channel. In this paper, we have designed OSTBC/QOSTBC and NOSTBC schemes for UWOC system, which can significantly improve the integrity of information transfer across the underwater optical wireless channels. These codes have been suitably conditioned to operate with an UWOC system employing intensity modulation. Monte-Carlo bit error rate simulations of the proposed schemes are plotted and presented with respect to the available transmit power in dB. © 2023 IEEE.