Browsing by Author "Joshi, Sandeep"

Now showing 1 - 20 of 56

5G in Healthcare: A Survey
(Taylor & Francis, 2023) Joshi, Sandeep
This text discusses problems and needs with the implementation of a 5G mobile communications system in the healthcare sector. It covers the issues related to advanced modulation schemes, telehealth, and remote diagnosis. It discusses important topics including virtual healthcare monitoring, spectrum sensing techniques, the role of 5G in medical applications, the role of nano- communication in healthcare informatics, and remote diagnosis. The text will be useful for graduate students, academic researchers, and professionals in the fields of electrical, and electronics and communication engineering, and allied healthcare. This book: Discusses novel architecture to manage the allocation of resources, and the interference issue among existing and advanced radios Provides focus to estimate the performance, cost and accommodation of the next generation technology design for the IoT, modern health- care, and education Covers advanced technologies and their role in healthcare Discusses key topics including spectrum access, advanced waveforms, which can help in standardization of 5G based smart hospital Explores the impact of telemedicine in smart healthcare This reference text covers the latest advances in the field of 5G mobile communication for healthcare informatics, addressing both original algorithm development and new applications of 5G mobile Communications.
Analysis of dedicated and shared device-to-device communication in cellular networks over Nakagami-m fading channels
(IET, 2017-07) Joshi, Sandeep
Device-to-device (D2D) communication, unlike conventional cellular communication, is described as the direct communication between devices bypassing the network infrastructure. This mode of direct communication, due to its advantages, is being proposed as an integral part of the next generation cellular networks with the additional interference between the users being a challenge. In this study, the authors develop an analytical framework for a D2D-enabled downlink cellular network with Nakagami-m fading between the D2D communication links. The authors derive tractable expressions for the coverage probability of D2D links and cellular users, considering different propagation conditions experienced by D2D and cellular links. Using stochastic geometry, the authors provide the coverage probability analysis for the dedicated network, having orthogonal frequency resource allocation, and for the shared network, where the frequency resources are reused. Furthermore, the authors extend the coverage probability analysis to include interference-limited dedicated and shared networks. Numerical results corroborate their analysis. The authors also derive the expressions for ergodic spectral efficiency of D2D links for both dedicated and shared networks. The results obtained are helpful in understanding the system behaviour and show the dependence of network performance on the system parameters.
Applied and Digital Electronics
(Vikas Publishing, 2015) Joshi, Sandeep
Applied and Digital Electronics covers the syllabus requirements of the subject for West Bengal State Council of Technical Education. It aims at giving a strong understanding of the concepts required for designing complex electronic circuitry, computers, and communication systems. Each chapter of the book begins with an introduction of the topic and then explains the complex concepts in a simple way. The text has been supplemented with solved examples and relevant diagrams.
Buffer-Aided AF Cooperative Relaying Network with NOMA Transmission Scheme
(IEEE, 2020) Joshi, Sandeep
A butter-aided cooperative communication network employing non-orthogonal multiple access (NOMA) with fixed gain amplify-and-forward relaying is considered in this paper. Using NOMA scheme the mobile user which acts as a relay and is a strong user transmits the information to the two destination devices which are the weak users. The strong user is aided with a data butter and it amplifies and forwards the superposed signal received from the source. The butter at the relay has the potential to offer flexible scheduling of data reception and transmission by utilizing the channel resources and also helps in offloading the data servers. The approximate upper bound expressions for the successful transmission probabilities at the two weak users are derived considering that the device acting as a relay (strong user) has global channel state information. By adopting a Markov chain approach to model the evolution of the strong user's butter status, the closed-form expression for the outage probability and the average packet delay of the system are also derived. Numerical results corroborate the derived analytical results.
Channel Characterization for Devices in a Turbulent Diffusive Environment: A Mobile Molecular Communication Approach
(IEEE, 2019-12) Joshi, Sandeep
Mobile molecular communication among nano-devices has potential applications in diverse fields such as targeted drug delivery systems, designing and deploying nano-sensors and nano-actuators for detection, treatment of a large set of diseases, and monitoring of environmental conditions. In this paper, we consider a mobile molecular communication system where the fluid medium has a fully developed homogeneous turbulence, and both the transmit and the receive nano-devices are mobile. The considered molecular communication system uses information molecules to transmit information from a transmit nano-device to a receive nano-device. To fully characterize and describe this mobile molecular communication channel, we derive its statistical properties like mean, correlation function, and distribution functions. We then analyze the performance of the system in terms of its symbol error probability and channel capacity. Numerical results corroborate the derived analytical findings.
Channel Estimation and Performance Analysis of a Wide-FOV Visible Light Communication System With Random Receiver Orientation and Location
(IEEE, 2023-03) Joshi, Sandeep
A practical visible light communications (VLC) system accounting for the effect of the random orientation and the random location of the photo-detector receiver is considered in this paper. The characterizations of the random orientation of the receiver, modeled as the receiver employing wide field of view (FOV) for data detection, and the random location of the receiver are utilized to derive the statistics for the scenarios in which (i) only the orientation of the receiver is random, (ii) only the location of the receiver is random, and (iii) both the orientation and location of the receiver are random. Furthermore, the receiver structures for a fully coherent VLC system and a VLC system employing the least-squares technique for channel estimation are proposed. Employing the receiver structures, the closed/series-form expressions for the symbol error probabilities are derived for all three scenarios of practical VLC channel models. The numerical results particularly show the crucial role of the ratio of the distance of the location of the receiver from the center of the receiving plane to the distance from the light-emitting diode (LED) to the center of the receiving plane in the performance of all the considered VLC systems.
Channel Estimation-Based Rate Maximization for IRS-Aided UAV Wireless Communication Systems
(IEEE, 2024-08) Joshi, Sandeep; Chaubey, Vinod Kumar
In 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.
Characterization and Performance Optimization of Heterogeneous Media-Based Mobile Molecular Communication Systems
(IEEE, 2024-11) Joshi, Sandeep
In this letter, we study a three-dimensional heterogeneous media-based mobile molecular communication (MC) system, with the communicating devices as point transmitters and passive spherical-shaped receiver nano-machines. For the shorter time range, the diffusion process faces internal diffusivity fluctuations, due to which communicating devices and the information-carrying molecule’s diffusivity exhibit stochastic behavior. We propose a stochastic diffusivity-based mobile MC system model, which considers the non-Gaussian Brownian displacement of molecules and characterize it by the channel impulse response, and derive its mean. We consider the molecule’s constrained time-varying Poisson statistical diffusive channel model at a high inter-symbol interference regime and analyze the channel performance in terms of the bit error rate and channel capacity. Furthermore, the numerical results are verified through particle-based simulations.
Characterization of Stochastic Diffusivity-Based Information Particles in Molecular Communication Systems
(IEEE, 2024-07) Joshi, Sandeep
This work considers a three-dimensional mobile molecular communication (MC) via an anomalous-diffusion-based system. The communicating devices in the considered MC system are identical and can move anomalously with emitted information-carrying molecules. We propose a stochastic diffusivity-based anomalous diffusion model which considers the non-Gaussian Brownian displacement of the molecules using the subordination approach. The proposed stochastic diffusivity model for mobile MC channels is characterized by the channel impulse response (CIR), and its mean is derived. We consider a discrete-time statistical channel model at a high inter-symbol interference regime and derive the bit error rate expressions. We also derive the asymptotic expression and upper bound of the capacity for the subordination approach. Furthermore, we show the degree of accuracy through root mean square error for the Poisson and Gaussian distributions.
Characterizing the Probability of Collision Between Information Particles in Molecular Communications
(IEEE, 2021-06) Joshi, Sandeep
Most of the works reported in the existing molecular communication literature make an assumption that the information molecules released in the fluid medium do not interact with each other and follow independent and identically distributed paths to the receiver. However, there are certain molecular transport paradigms where such an assumption does not hold and the interactions between the information molecules play an important role in characterizing such molecular communication processes. Motivated by this, we provide in this letter an analysis for the possible interaction between two information molecules that are released into the fluid medium a certain time interval apart in the case of a molecular timing channel. We calculate the probability that the two information molecules collide before any one of them is absorbed at the boundary. We also derive the distribution of the collision time and the collision position of the information molecules. Furthermore, numerical results corroborate our analysis.
Cooperative Device-to-Device Relaying Network with Power Line Communications
(IEEE, 2019) Joshi, Sandeep
Cooperative device-to-device communication with non- orthogonal multiple access (NOMA) employing additional power line communication technology is an effective way to increase the coverage and spectral efficiency of the next generation hybrid networks. In this paper, we present the outage analysis of a cooperative network with NOMA and decode-and-forward relaying assuming a direct link between the base station and the users. We consider a relaying network consisting of a wireless link for the strong user and the weak user having both wireless and a wired link which is assumed as a power line link. The wireless links are subjected to Nakagami-m fading and the power line link experiences Rayleigh fading. The outage probability expressions for both the strong and the weak users are derived assuming power division NOMA and perfect successive interference cancellation at the receivers. We also derive the optimal value of the NOMA power allocation coefficient minimizing the outage probability at the strong user and obtain the range of the power allocation coefficient between the power line and the wireless link at the weak user. Furthermore, numerical results validate the derived analytical results.
Coverage and Interference in D2D Networks With Poisson Cluster Process
(IEEE, 2018-05) Joshi, Sandeep
In this letter, we present an analytical framework for the coverage probability analysis in a device-to-device (D2D) network with the location of devices modeled as a Poisson cluster process. We consider Nakagami-m fading between the D2D communication links, which provides a more realistic scenario for the performance analysis. We assume a standard singular path loss model and use stochastic geometry as a tool for the interference and coverage probability analysis. Furthermore, we derive a closed form approximate expression and a bound on the coverage probability, and also include the interference-limited case. Numerical results corroborate our analysis.
Coverage Probability Analysis in a Device-to-Device Network: Interference Functional and Laplace Transform Based Approach
(IEEE, 2019-03) Joshi, Sandeep
In this letter, we provide an interference functional and Laplace transform based analysis using stochastic geometry to evaluate the expectation over the interference, which is further used to derive the coverage probability expressions for device-to-device (D2D) links. We assume a more practically relevant Nakagami-m fading distribution to model fading between the D2D communication links considering interference from both D2D and cellular links. We also derive a bound on the coverage probability, which simplifies the coverage computations at higher values of the fading parameter. Furthermore, the numerical results corroborate the presented coverage analysis.
A Cybertwin-Based 6G Cooperative IoE Communication Network: Secrecy Outage Analysis
(IEEE, 2022-07) Joshi, Sandeep
The sixth-generation (6G) communication networks being highly data-intensive and enabled by the Internet of Everything (IoE) are envisaged to find applications in various domains including smart healthcare, smart industry, and gaming. In this article, a novel hybrid 6G-based cybertwin cooperative architecture is studied and an analytical framework for the secrecy outage analysis is presented. The base station (BS) considered utilizes nonorthogonal-multiple-access for content request transmission to the cybertwin host and the server with a direct communication link present between the BS and the server. A wireless link experiencing Nakagami- m fading is considered which is further assisted in the communication network by a wired link which is a power line communication link and experiences Rayleigh fading, for the communication between the cybertwin host and the server. Secrecy error probability expressions are derived for the cybertwin host and the server for the scenario when both the wireless and the wired links are available for communication and only the wireless link is available for communication. Furthermore, the presented analytical results are corroborated with simulation results which demonstrate the optimality of operating the wireless links at lower signal-to-noise ratio (SNR) values. It is observed that for the lower values of Nakagami fading parameter, better secrecy performance is observed with the usage of wired link along with the wireless link, and also the secrecy performance of the cybertwin host and the server is dependent on the system parameters like the fading parameter and the average SNR.
Deep Learning Based Super Resolution Network for Channel Estimation
(Taylor & Francis, 2024-12) Joshi, Sandeep
This paper proposes and investigates a deep learning-based channel estimation scheme for wireless communication system. In this approach, the channel response in pilot positions is considered a low-resolution image, which is further converted into a high-resolution image using the super-resolution (SR) network. It is observed that the proposed model shows an improvement of 50% and 42.5% as compared to the ChannelNet and super-resolution convolutional neural network, respectively, in the case of 16 pilots. The novelty of the proposed SR model is its low complexity, as it uses one model instead of two for channel estimation. Besides, the proposed SR model uses fewer pilots for channel estimation, making it bandwidth-efficient and fast. Furthermore, the proposed model is compared using extensive simulations for benchmarking.
Design of a Scalable IRS-Assisted Communication System with Generalized Beamforming Approach
(IEEE, 2024-09) Joshi, Sandeep
Intelligent reflecting surfaces (IRS) are envisaged to be a prominent part of the next-generation communication networks. To exploit the benefits of the IRS, beamforming is indispensable. In this work, we propose a generalized beamforming algorithm for an IRS-based wireless system, along with the design of a hardware prototype to implement it. The algorithm is versatile enough to be deployed on an IRS array of arbitrary size with unit cells that have any number of discrete phase shifts. A prototype is designed with an array of single-bit phase shifting unit cells and a peripheral control circuit to demonstrate beamforming using the proposed algorithm.
Deterministic Linear Transmit Processing for Single-User MIMO Systems
(IEEE, 2020) Joshi, Sandeep
In this paper, we consider deterministic linear precoding and channel state information based linear combining for a single-user multiple-input multiple-output communication system in flat Rayleigh fading. The precoding matrix is chosen such that it maximizes a bound on the average received signal-to-noise ratio (SNR), whereas the combining matrix is chosen such that it maximizes the instantaneous output SNR. We present techniques for obtaining the precoder and combiner matrices and analyze the error performance of the system in terms of the pairwise error probability.
An efficient federated transfer learning approach for Multi-UAV systems
(IEEE, 2025-05) Joshi, Sandeep; Rajya Lakshmi, L.
Recent advances in multi-unmanned aerial vehicle (UAV) based federated learning do not take into consideration the massive computational requirements of modern deep learning models on mobile UAV s. Additionally, there has been significant progress that shows that the information transmitted between the federated agent and the central hub can be attacked to undermine the privacy of the data. We propose a novel multi-UAV-based federated transfer learning system that drastically reduces the computational burden overall, shifts it from UAV s to the ground fusion center, and reduces the bandwidth requirements while enhancing its secure nature. The proposed system makes multi-UAV learning significantly fast, reliable, power efficient, and practically feasible. Furthermore, we provide simulation and experimental results to demonstrate the effectiveness of the proposed system
Employee Face Recognition Scheme Using A Common Space Mapping Approach
(IEEE, 2022-07) Joshi, Sandeep
In this work, we present a FaceNet based ‘two branch’ model for employee face recognition in low resolution images captured using substandard camera sensors. Our model involves a common space mapping approach using two deep convolutional neural networks (DCNNs) that map the low resolution and high resolution face images to a common space. The model is trained such that the distance between the two mapped images in the common space is minimized. Then, a logistic regression classifier is used to classify the mapped image by the identity of the employee. We show through simulations that the presented model achieves a recognition accuracy of 99.84%, 98.88%, and 95.53% on 36×36, 24×24, and 16×16 resolution images, respectively, for 209 subjects. Furthermore, the proposed model has less space (90 Megabytes) and computation requirements making it suitable for systems having low computing power and memory.
Envelope Distribution of Two Correlated Complex Gaussian Random Variables and Application to the Performance Evaluation of RIS-Assisted Communications
(IEEE, 2022-09) Joshi, Sandeep
The operation of point-to-point communication assisted with reconfigurable intelligent surface, where the multi-hop channels between the source and the destination are subject to Rician fading but are not necessarily independent, is investigated. Considering binary phase-shift keying signaling for the data transmission and optimal maximum-likelihood detection at the receiver, a system performance evaluation is conducted in terms of reliability and capacity. For such, the distributions of the magnitude of the product of the complex channel gains are first obtained for both, the case when the channel gains are independent and the case when they are correlated. Subsequently, expressions of the system’s error rate and the upper-bounds on the average capacity are obtained for the said correlated and uncorrelated channel cases. Numerical results corroborating the analysis are also presented. In particular, it is revealed that correlation between the channels has negligible effect on the error rate when the fading is Rayleigh distributed, and that an increase in the value of the Rician parameter pertaining to the channel between the receiver pair has reduced impact on the reduction of the error rate, which provides practical guidelines for system deployments with high reliability.