Journal Articles
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Item Asymptotic bit-error rate analysis of quadrature amplitude modulation and phaseshift keying with OFDM RoFSO over M turbulence in the presence of pointing errors(Institution of Engineering and Technology journals@theiet.org, 2018) Krishnan, K.; Jana, U.; Kumar, B.K.In case where installation of optical fibre is not practically reliable, the new generation wireless communication popularised as free-space optics (FSO) systems can be used to transmit radio-frequency (RF) signals. FSO technology can efficiently transfer multiple RF signals, and this new technique is commonly referred as radio-on-FSO (RoFSO). The major challenges in this technology are atmospheric turbulence and pointing errors. In this study, the authors analysed the performance of RoFSO links employing the orthogonal frequency division multiplexing (OFDM) scheme under both modulation formats namely quadrature amplitude modulation and phase shift keying in the newly developed Málaga or M distribution turbulent channel model. The performance is evaluated with consideration of both scintillation and pointing errors in M distribution channel for higher values of the carrier-to-noise plus distortion ratio. M distribution channel serves as an effective generalised model which unifies all other available statistical channel models. The novel expressions of average bit-error rate has been derived and performance comparison has been done between the two modulation formats. This study identifies the crucial parameters that deteriorate the efficiency of the OFDM signal over FSO link which can be helpful in designing an optimal system. © The Institution of Engineering and Technology 2018.Item Tracking of Radar Targets With In-Band Wireless Communication Interference in RadComm Spectrum Sharing(Institute of Electrical and Electronics Engineers Inc., 2022) Gunnery, G.; Pardhasaradhi, B.; Prashantha Kumar, P.; Srihari, P.Radar and communication system (RadComm) spectrum sharing has received considerable attention from the research community in recent years. This paper considers the distributed radars present in the surveillance region with multiple in-band wireless communication transmitters (IWCTs). A new measurement model is proposed by considering both radar returns and returns due to IWCTs. The tracking performance is evaluated using the global nearest neighbor (GNN) tracker with an extended Kalman filter (EKF) for the received measurement set. A single radar case is considered, where near geometry scenario (IWCTs are placed near the radar and target) and far-geometry scenario (IWCTs are placed far from the radar and target) are considered to evaluate the tracking performance. It is observed that a large number of tracks are resulted due to IWCTs, and identifying the actual target track is ambiguous in a single radar case. Therefore, in the second case, multiple radars are placed to investigate the problem comprehensively. The track-to-track association (T2TA) is performed to identify the true target track on multiple tracks produced owing to the presence of IWCTs and the resulting tracks from all radars pertaining to the true targets. Once the true target tracks from each radar are identified, using the T2TA, the track-to-track fusion (T2TF) is carried out to improve the estimates of the true target. The simulation results are quantified with position root mean square error (PRMSE). The posterior Cramer-Rao lower bounds (PCRLBs) quantifying the achievable estimation accuracies are also presented. The simulation results reveal that the association and fusion of tracks from multiple radars identify the true target track with good accuracy and overcome the inability to determine the true track, as in the case of a single radar. Further, the results disclose that, as the number of radars increases, the T2TA and fusion improved the PRMSE. © 2022 IEEE.Item RIS Assisted Triple-Hop RF-FSO Convergent With UWOC System(Institute of Electrical and Electronics Engineers Inc., 2022) Bhargava Kumar, L.B.; Naik, R.P.; Krishnan, P.; Raj, A.A.B.; Majumdar, A.K.; Chung, W.-Y.The convergence of wireless optical communication (WOC) and radio-frequency (RF) systems is a promising technology that overcomes the shortcomings of standalone communication systems. By incorporating reconfigurable intelligent surfaces (RISs) on top of these WOC and RF communication systems, it is possible to circumvent the connection challenges associated with standard line of sight (LOS) communication links. Wireless communication systems with RIS assistance are a promising and evolving technology that enables more efficient and reliable link performance over long distances. The performance of the triple-hop RIS-assisted RF-FSO convergent with the underwater wireless optical communication (UWOC) system is investigated in this article. We considered the fading channel Nakagami-m over the RIS-RF connection and the fading channel Gamma-Gamma (GG) over the RIS-FSO and UWOC links. Then, the average bit error rate (ABER) and outage probability are determined using closed-form expressions. The ABER and outage probability performances of the triple-hop communication system is analysed by varying parameters such as turbulence, misalignment fading, and the number of RIS elements. The obtained results demonstrate an improvement in performance for low turbulence, low pointing error, and an increasing number of RIS elements. Additionally, the data demonstrate the accuracy of the analytical results. © 2013 IEEE.Item New Bit Pattern Based IPv6 Address Compression Techniques for 6LoWPAN Header Compression(Institute of Electrical and Electronics Engineers Inc., 2022) Geetha, V.; Bhat, A.; Thanmayee, S.Things in the world can be connected to the Internet through various technologies such as Wi-Fi, Bluetooth, IEEE 802.15.4 etc. Among all IPv6 over IEEE 802.15.4 looks promising for outdoor environments for connecting a very large number of resource constrained sensor nodes. 6LoWPAN is an adaptation layer to support IPv6 over IEEE 802.15.4 to overcome the challenge of the physical layer with respect to the limitation of 127 bytes of payload. 6LoWPAN supports header compression as one of its functions to reduce the number of bits in header by using compression techniques. Static Context Header Compression (SCHC) provides RuleID based header compression. This paper proposes further compression of address bits based on compressing leading zeros in IPv6 addresses. The proposed work is analysed with respect to Header compression HC1 of 6LoWPAN and SCHC techniques. The simulation results show compression of address bits are 10% to 40% more compared to traditional address compression of the 6LoWPAN address compression when continuous zeroes are present in the address. The compression of address bits provides sufficient space for sending data payload in one frame during communication. © 2013 IEEE.Item Performance Analysis of Spectrum Sharing Radar in Multipath Environment(Institute of Electrical and Electronics Engineers Inc., 2023) Gunnery, G.; Pardhasaradhi, B.; Mahipathi, A.C.; Prashantha Kumar, P.K.; Srihari, P.; Cenkarmaddi, L.R.Radar based sensing and communication systems sharing a common spectrum have become a potential research problem in recent years due to spectrum scarcity. The spectrum sharing radar (SSR) is a new technology that uses the total available bandwidth (BW) for both radar based sensing and communication. Unlike traditional radar, the SSR divides the total available BW into radar-only and mixed-use bands. In a radar-only band, only radar sensor signals can be transmitted and received. In contrast, radar and communication signals can both be transmitted and received in the mixed-use band. Taking such BW sharing into account, this paper investigates the performance of SSR in an information-theoretic sense. To evaluate performance, mutual information (MI), spectral efficiency (SE) and capacity (C) metrics are used. Initially, this paper considered a clean environment (no multipath) in order to evaluate performance metrics in the mixed-use band with and without successive interference cancellation. Following that, this paper addresses the performance of BW allocation by allocating low to high BW in mixed-band. Furthermore, the performance metrics are extended to account for the multipath environment, and the same analogy as in a clean environment is used. In addition, the MI and SE of traditional radar system is taken into account when comparing the performance of SSR with and without the use of the SIC. Finally, MI and capacity results show that using the SIC scheme in a mixed-use band yields performance comparable to traditional radar and communication system. In terms of SE, the SSR with SIC scheme outperforms traditional radar and communication system. © 2020 IEEE.Item Performance Analysis of MIMO-EGC System for the Underwater Vertical Wireless Optical Communication Link(Institute of Electrical and Electronics Engineers Inc., 2023) Savidhan Shetty, S.C.S.; Naik, R.P.; Shripathi Acharya, U.S.; Chung, W.-Y.In this paper, we have investigated the performance of an underwater vertical wireless optical communication (UVWOC) link employing multiple input-multiple output (MIMO) operating in conjunction with equal gain combing (EGC) techniques perturbed by weak and strong turbulence in the presence of pointing errors and attenuation losses. Vertical underwater turbulence, which varies from layer to layer due to temperature and salinity variation connected to depth, is modeled using hyperbolic tangent log-normal (HTLN) distribution in the case of weak underwater turbulence and gamma-gamma (GG) distribution in the case of strong underwater turbulence. Novel closed-form expressions quantifying the average bit error rate (BER) have been derived for the UVWOC MIMO EGC system for weak and strong turbulence regimes. The expression for the average BER associated with the UVWOC link for different values of pointing error, differing vertical layer depth, modulation types, and differing numbers of sources and detectors have been determined. In addition, closed-form expressions for the outage probability (OP) and ergodic channel capacity (ECC) have been derived for the UVWOC MIMO EGC system. The accuracy of all closed-form expressions derived in the paper has been verified using Monte Carlo simulations. © 2013 IEEE.Item Development of a Novel Real-Time Environmental Parameters Monitoring System Based on the Internet of Things with LoRa Modules in Underground Mines(Springer, 2023) Kumar Reddy, S.K.; Naik, A.S.; Raj, M.G.The mining industry relies on extracting valuable minerals through underground mining. Many industries have implemented automation to enhance workplace safety, optimize operations, improve responses to events, and achieve cost-effectiveness. A real-time communication and monitoring system is indispensable in underground mines to prevent significant hazards and improve safety in underground mines. However, the environmental conditions of underground mines are affected by toxic, flammable, combustible gases and dust. The harmful gases are a significant concern as they can cause gas explosions. Internet of Things (IoT) enabled real-time communication system with Long Range (LoRa) transceiver module is designed and developed to measure the underground mine environmental parameters, temperature, and humidity. The LoRa-based proof of concept (POC) system is tested and evaluated at the surface level and in two underground mines. The LoRa module radio waves range test is carried out to measure the received signal strength indicator (RSSI) value at the surface level. In addition, the developed system is tested and evaluated at different positions of underground mines to measure environmental parameters in straight and curved tunnels. The experimental results represent successful IoT with LoRa-based wireless communication between underground mine tunnels to the surface, wireless transmission of parameters at the straight tunnels, and curved tunnels of underground mines. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Item RTEPMS: Real-Time Environmental Parameters Monitoring System Using IoT-Based LoRa 868-MHz Wireless Communication Technology in Underground Mines(Institute of Electrical and Electronics Engineers Inc., 2024) Naik, A.S.; Kumar Reddy, S.K.; Raj, M.G.In underground mining, the real-time monitoring of environmental parameters plays a pivotal role in ensuring the safety of mining operations and personnel. This article explores the integration of Long Range (LoRa) wireless communication technology and the Internet of Things (IoT) to bolster safety measures and prevent potential accidents within underground mines. The environmental parameters in underground mines include Oxygen (O2), Carbon Dioxide (CO2), Carbon Monoxide (CO), Methane (CH4), Nitric Oxide (NO), Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), Hydrogen Sulfide (H2S), Ethylene Oxide (EO), Temperature and Humidity. Currently, underground mines in India use portable multi-gas detector devices to measure environmental parameters. HPD13A LoRa 868 MHz based Real Time Environmental Parameters Monitoring System (RTEPMS) is designed and developed to facilitate real-time data collection in underground mines. In addition, the developed RTEPMS system is tested and evaluated at the open surface level and in one of the underground mines in India. The experimental results represent successful LoRa-based wireless communication established in an underground mine with data acquisition and real-time processing. Major parameters exceeding threshold limits in the underground mine environment include O2, CO, CO2, NO2, and EO. The data correlation between LoRa-based RTEPMS and multi-gas detector devices is 69.47% for CO2 and 72.38% for CO, while the values for CH4 and H2S are nearly zero, indicating their presence in underground mines is almost negligible. The RTEPMS is an affordable solution for smaller and less affluent underground mines. It alerts mine workers if environmental parameters exceed threshold limits during emergencies. © 2013 IEEE.Item A survey on wireless sensor network (applications and architecture)(Inderscience Publishers, 2024) Mahapatra, R.K.; Kaliyath, Y.; Shet, N.S.V.; Mahapatro, S.R.; Satapathi, G.S.; Prusty, S.B.; Patro, B.S.Proliferation of the wireless sensor network is due to the advancement in wireless networks, information technologies, miniaturisation of sensors as well as convergence of MEMS technology, wireless communication and digital electronics. These wireless networks interface the physical world to the computing (virtual) world. In recent years, the availability of smaller, cheaper and intelligent sensors on a large scale has motivated the deployment of sensors in various applications such as smart city, smart home, smart grid, automated vehicles, etc. The sensor plays an important role in internet of things. This survey reports current research activities, applications, characteristics, architecture and case study of WSNs. In addition to this open research issues/problems are discussed. The aim is to present a comprehensive study of the literature on several aspects of wireless sensor network such as application and architecture. © 2024 Inderscience Enterprises Ltd.Item Performance of Spatially Coupled LDPC Codes over the Underwater Wireless Optical Channel with Strong Turbulence and Pointing Errors(Institute of Electrical and Electronics Engineers Inc., 2024) Padala, S.K.; D'Souza, J.The major problems in an underwater wireless optical communication (UWOC) link are turbulence induced fading and pointing errors. In this paper, we have investigated the bit error rate (BER) performance of spatially coupled low-density parity-check (SC-LDPC) coded horizontal UWOC link over a strong turbulent channel model with pointing errors. The performance of this link for different channel and code parameters has been studied using simulations. It has been observed that a rate 1/2 ARJA protograph based SC-LDPC code with graph lifting factor of 256 gives a coding gain of 47 dB at a BER of 10^-4 for strong turbulence channel model with pointing errors. An analytical BER expression for an uncoded UWOC link under strong turbulence with pointing errors for the On-Off Keying modulation technique has been derived. A multidimensional protograph based extrinsic information transfer algorithm has been developed to obtain the decoding thresholds for different channel parameters and code rates. We have also studied the SC-LDPC coded vertical UWOC link performance for some specific strong turbulence channel parameters with pointing errors and observed that as the link length increases from 20 m to 40 m , the performance gap between the hypothetical and cascaded channel models increases from 1.1 dB to 5.5 dB. © 2013 IEEE.