Indrakshi Dey

• Doctor of Philosophy
• Head of Division – Programmable Autonomous Systems (PAS) at Walton Institute for Information and Communication Systems Science

High‐dimensional quantum states, or ‘qudits’, provide significant advantages over traditional qubits in quantum communication, such as increased information capacity, enhanced noise resilience, and reduced information loss. Despite these benefits, their implementation has been constrained by challenges in generation, transmission, and detection. Th...

The onset of old age is often accompanied by various physiological and mental changes, with anxiety and depression being prevalent mental health disorders that can exacerbate other medical conditions and significantly reduce life expectancy. Despite the growing need for effective treatment, the global shortage of mental health professionals, couple...

Human fertility monitoring, whether for natural conception or artificial insemination and fertilization, presents a significant challenge for both physicians and patients. Detecting the presence of eggs in the fallopian tube and timely communication of this information to the healthcare team and the patient remains an elusive goal; in this paper, w...

The onset of old age brings physiological and mental changes, with anxiety and depression being common mental disorders that can trigger other health issues and reduce lifespan. However, due to a global shortage of mental health professionals, combined with a growing population and limited awareness, these disorders often go undiagnosed. Music ther...

The key research question we are addressing in this paper, is how local distance information can be integrated into the global structure determination, in the form of network graphs realization for IoT networks. IoT networks will be pervading every walk of life over the next few years with the aim of improving quality of life and enhancing surround...

The onset of old age brings physiological and mental changes, with anxiety and depression being common mental disorders that can trigger other health issues and reduce lifespan. However, due to a global shortage of mental health professionals, combined with a growing population and limited awareness, these disorders often go undiagnosed. Music ther...

The rapid pervasivity of the Internet of Things (IoT) calls for an autonomous and efficient resource management framework to seamlessly register and discover facilities and services. Cloud-Fog-Automation (CFA) standards provide a robust foundation for multi-tiered wireless architectures, enhancing cyber-physical system performance with advanced abs...

Due to rapid advancements in the field of Internet of Medical Things (IoMT), a continuous influx of health data is being generated at a large scale. The primary objective of IoMT solutions is to transmit critical health data from patients to remote locations in real-time. Apart from remote patient monitoring, the extensive collection of health data...

The ubiquitous Internet of Things (IoT) and sensing technologies provide an interesting opportunity of remote health monitoring and disease risk categorisation of populations. An end‐to‐end architecture is proposed to facilitate real‐time digital dashboards to visualise general anxiety risks of patients, especially during a pandemic, such as COVID‐...

Classical game theory is a powerful tool focusing on optimized resource distribution, allocation, and sharing in classical wired and wireless networks. As quantum networks are emerging as a means of providing true connectivity between quantum computers, it is imperative and crucial to exploit game theory for addressing challenges such as entangleme...

The energy sector is experiencing a paradigm shift with the swift adoption of distributed energy sources, renewables, electric vehicles, and an evolving consumer-utility relationship. This necessitates the strategic integration of advanced Information and Communication Technologies (ICT) and the Internet of Things (IoT) to address the emerging chal...

The dairy industry is experiencing a surge in data from Edge devices, using spectroscopic techniques for milk quality assessment. Milk spectral data can help understand the species of milk producer and detect inter-species adulteration. Transmitting raw milk spectral data to the cloud for processing faces challenges due to limited network resources...

The 4.0 industrial revolution, also known as Industry 4.0, is characterized by the integration of advanced technologies such as artificial intelligence, Internet of Things, cloud computing, augmented/virtual reality, and big data into various industries, including healthcare. The application of Industry 4.0 technologies in healthcare domain is refe...

The healthcare crisis emerged due to COVID-19 has escalated mental health predicaments ranging from several mental diseases and disorders. Mental illnesses triggered in the pandemic have shaped-up a challenging situation for the mental health practitioners to predict psychological distresses among the patients infected with COVID-19, healthcare pra...

With the rapid deployment of quantum computers and quantum satellites, there is a pressing need to design and deploy quantum and hybrid classical-quantum networks capable of exchanging classical information. In this context, we conduct the foundational study on the impact of a mixture of classical and quantum noise on an arbitrary quantum channel c...

Classical game theory is a powerful tool focusing on optimized resource distribution, allocation and sharing in classical wired and wireless networks. As quantum networks are emerging as a means of providing true connectivity between quantum computers, it is imperative and crucial to exploit game theory for addressing challenges like entanglement d...

Internet-of-Things (IoT) devices are low size, weight and power (SWaP), low complexity and include sensors, meters, wearables and trackers. Transmitting information with high signal power is exacting on device battery life, therefore an efficient link and network configuration is absolutely crucial to avoid signal power enhancement in interference-...

Industrial Internet-of-Things (IIoT) involve multiple groups of sensors, each group sending its observations on a particular phenomenon to a central computing platform over a multiple access channel (MAC). The central platform incorporates a decision fusion center (DFC) that arrives at global decisions regarding each set of phenomena by combining t...

Efficient resource allocation (RA) strategies within massive and dense Internet of Things (IoT) networks is one of the major challenges in the deployment of IoT-network based smart ecosystems involving heterogeneous power-constrained IoT devices operating in varied radio and environmental conditions. In this paper, we focus on the transmit power mi...

In this paper, we develop a tractable mathematical model and an emulation framework for communicating information through water using acoustic signals. Water is considered one of the most complex media to model due to its vastness and variety of characteristics, which depend on the scenario, the type of water body (lakes, rivers, tanks, sea, etc.),...

Multiple photonic degrees of freedom can be explored to generate high-dimensional quantum states; commonly referred to as `qudits'. Qudits offer several advantages for quantum communications, including higher information capacity, noise resilience and data throughput, and lower information loss over different propagation mediums (free space, optica...

In this paper, we develop a tractable mathematical model and emulation framework for communicating information through water using acoustic signals. Water is considered as one of the most complex mediums to model owing to its vastness and variety in characteristics depending on the scenario, what kind of water-body (lakes, rivers, tanks, sea etc.)...

In this article, we are proposing a closed-form solution for the capacity of the single quantum channel. The Gaussian distributed input has been considered for the analytical calculation of the capacity. In our previous couple of papers, we invoked models for joint quantum noise and the corresponding received signals; in this current research, we p...

In this article, we propose a space spreading-assisted framework that leverages either time or frequency diversity or both to reduce interference and signal loss owing to channel impairments and facilitate the efficient operation of large-scale dense Internet-of-Things (IoT). Our approach employs dispersion of data-streams transmitted from individu...

Industrial Internet-of-Things (IIoT) involve multiple groups of sensors, each group sending its observations on a particular phenomenon to a central computing platform over a multiple access channel (MAC). The central platform incorporates a decision fusion center (DFC) that arrives at global decisions regarding each set of phenomena by combining t...

For a continuous-input-continuous-output arbitrarily distributed quantum channel carrying classical information, the channel capacity can be computed in terms of the distribution of the channel envelope, received signal strength over a quantum propagation field and the noise spectral density. If the channel envelope is considered to be unity with u...

The primary contribution of this paper is to characterize the propagation of acoustic signal carrying information through any medium and the interaction of the travelling acoustic signal with the surrounding medium. We will use the concept of damped harmonic oscillator to model the medium and Milne's oscillator technique to map the interaction of t...

Fertility monitoring in humans for either natural conception or artificial insemination and fertilization has been a critical challenge both for the treating physician and the treated patients. Eggs in human female can be fertilized when they reach the Fallopian tube from the upper parts of the reproductive system. However, no technology, till date...

Increasing advancements in the medical equipment and wearable and implantable devices and technologies promise to revolutionize the healthcare sector. Today is the era of delivering personalized healthcare with the help of technologies such as the Internet of Things (IoT) and the Internet of Medical Things (IoMT), smartphone applications, artificia...

We use the concept of coupled quantum harmonic oscillators to model the propagation environment in which a quantum link carrying either classical or quantum information operates. Using the analogy between the paraxial optical wave equation and the stationary Schrodinger equation and applying the Caldirola-Kanai Hamiltonian for solving the time-depe...

A Bayesian game theoretic model is developed to dynamically select channel sensing intervals in a massively dense network of Internet of Things. In such networks, the core objective is to minimize every node's energy consumption while having incomplete information about other nodes actively communicating in the network. Selecting channel sensing in...

The ubiquity of sensor technology and the Internet of Things prompted us to propose to develop a real-time digital dashboard to visualize the anxiety risks of populations during a pandemic, as in the case of COVID-19. To this end, here we provide an end-to-end communication architecture to detect physiological data related to heart rate, blood pres...

div>Denoising of signals in an Internet-of-Things (IoT) network is critically challenging owing to the diverse nature of the nodes generating them, environments through which they travel, characteristics of noise plaguing the signals and the applications they cater to. In order to address the abovementioned challenges, we conceptualize a generalize...

div>Denoising of signals in an Internet-of-Things (IoT) network is critically challenging owing to the diverse nature of the nodes generating them, environments through which they travel, characteristics of noise plaguing the signals and the applications they cater to. In order to address the abovementioned challenges, we conceptualize a generalize...

div> The ubiquity of sensor technology and the Internet of Things prompted us to propose to develop an end-to-end communication architecture for real-time digital dashboards to visualize the anxiety risks of a population during a pandemic, as in the case of COVID-19. Such an architecture can be regarded as the next-generation anxiety risk classif...

div> The ubiquity of sensor technology and the Internet of Things prompted us to propose to develop an end-to-end communication architecture for real-time digital dashboards to visualize the anxiety risks of a population during a pandemic, as in the case of COVID-19. Such an architecture can be regarded as the next-generation anxiety risk classif...

div>The primary contribution of this paper is to develop a realistic yet mathematically tractable channel emulator for underwater acoustic communications (UWAC) channels. Our proposed emulator is based on the Wide-Sense Stationary Uncorrelated Scattering (WSSUS) assumption, where the channel samples are generated using finite sum-of-sinusoids (SOS)...

div>The primary contribution of this paper is to develop a realistic yet mathematically tractable channel emulator for underwater acoustic communications (UWAC) channels. Our proposed emulator is based on the Wide-Sense Stationary Uncorrelated Scattering (WSSUS) assumption, where the channel samples are generated using finite sum-of-sinusoids (SOS)...

Social distancing has been regarded as a key method by the authorities worldwide to manage the pandemic of COVID-19. Digital technologies play a crucial role to support the social, professional and economic activities when people are forced to stay locked-down in their homes. Internet of things (IoT) technologies have a track of providing high qual...

COVID-19 affects the mental health of many people around the world. In particular, isolation situations due to lockdown have become more challenging for elderly people as they have limited access to technology. At the same time, technologies of remote systems using Internet of Things (IoT) have emerged as a pivotal role for healthcare management an...

The primary contribution of this chapter is to provide an overview of different denoising methods used for signal processing in IoT networks from the perspectives of physical layer in the network. The chapter starts with the introduction to different kinds of noise that can be encountered in any kind of wireless communication networks, different ki...

In this letter, we consider the plaguing, yet rarely handled problem of interference resulting from superposition of multiple sensor signals in time, when sent over a multiple access channel (MAC) in wireless sensor networks (WSNs). We propose space-time spreading (STS) of local sensor decisions before reporting them over a MAC to i) minimize inter...

In this chapter, the fundamentals of distributed inference problem in wireless sensor networks (WSN) is addressed and the statistical theoretical foundations to several applications is provided. The chapter adopts a statistical signal processing perspective and focusses on distributed version of the binary-hypothesis test for detecting an event as...

In this paper, in order to tackle major challenges of spectrum exploration \& allocation in Cognitive Radio (CR) networks, we apply the general framework of Decision Fusion (DF) to wideband collaborative spectrum sensing based on Orthogonal Frequency Division Multiplexing (OFDM) reporting. At the transmitter side, we employ OFDM without Cyclic Pref...

A recently conducted indoor-to-outdoor measurement campaign for investigating the propagation characteristics of an $8 \times 8$ virtual multiple-input-multiple-output (MIMO) based wireless sensor network (WSN) is presented in this paper. The campaign is conducted in an instrumentation room devoid of windows, but filled with different noisy electri...

In this paper, we investigate the practical implication of employing virtual massive multiple-input-multiple output (MIMO) based distributed decision fusion (DF) for collaborative wideband spectrum sensing (WSS) in a cognitive radio (CR)-like network. Towards that end, an indoor-only measurement campaign has been conducted to capture the propagatio...

In this letter, we propose space-time spreading (STS) of local sensor decisions before reporting them over a wireless multiple access channel (MAC), in order to achieve flexible balance between diversity and multiplexing gain as well as eliminate any chance of intrinsic interference inherent in MAC scenarios. Spreading of the sensor decisions using...

In this paper, in order to tackle major challenges of spectrum exploration & allocation in Cognitive Radio (CR) networks, we apply the general framework of Decision Fusion (DF) to wideband collaborative spectrum sensing based on Orthogonal Frequency Division Multiplexing (OFDM) reporting. At the transmitter side, we employ OFDM without Cyclic Prefi...

div>An increasing number of emerging applications, e.g., Internet of Things (IoT), vehicular communications, augmented reality, and the growing complexity due to the interoperability requirements of these systems, lead to the need to change the tools used for the modeling and analysis of those networks. Agent-Based Modeling (ABM) as a bottom-up mo...

div>An increasing number of emerging applications, e.g., Internet of Things (IoT), vehicular communications, augmented reality, and the growing complexity due to the interoperability requirements of these systems, lead to the need to change the tools used for the modeling and analysis of those networks. Agent-Based Modeling (ABM) as a bottom-up mo...

An increasing number of emerging applications, e.g., Internet of Things (IoT), vehicular communications, augmented reality, and the growing complexity due to the interoperability requirements of these systems, lead to the need to change the tools used for the modeling and analysis of those networks. Agent-Based Modeling (ABM) as a bottom-up modelin...

In this paper, we investigate the practical implications of employing virtual multiple-input-multiple output (MIMO) systems for prototyping future-generation wireless sensor networks, especially in the light of recently proposed distributed detection based decision fusion rules. In order to do that, an indoor-to-outdoor measurement campaign has bee...

A recently conducted indoor-to-outdoor measurement campaign for investigating the propagation characteristics of an 8 x 8 virtual multiple-input-multiple-output-based wireless sensor network is presented in this paper. The campaign is conducted in an instrumentation room devoid of windows, but filled with different noisy electrical and measuring un...

This letter presents a detailed study for indoor wireless environments, where transmit power, rate and target bit error rate (BER) are varied to increase spectral efficiency. The study is conducted for the recently proposed joint fading and two-path shadowing (JFTS) channel model, which is shown to be accurate for modeling non-Gaussian indoor WLAN...

Performance of common digital modulation techniques is analyzed over indoor wireless environments modeled through the recently proposed joint fading and two-path shadowing (JFTS) channel model. Mathematically tractable expressions for the instantaneous signal-to-noise ratio (SNR) statistics, average bit error rates (ABER) and achievable channel cut...

In this letter, we consider the joint fading and twopath shadowing (JFTS) channel model which has been found suitable for characterizing indoor large open office environments with low mobility and stationary users. We derive useful expressions of fundamental channel statistics like the number of level crossings in time, frequency and space as well...

In this letter, we derive a mathematically-tractable expression for the outage probability in presence of self-interference over indoor wireless environments modeled through the recently proposed joint fading and two-path shadowing (JFTS) channel model. The effect of self-interference is studied under two different conditions encountered in single...

The performance of rate adaptive M-ary quadra-ture amplitude modulation (M-QAM) and adaptive trellis-coded M-QAM in large open office indoor wireless environments is studied in this paper. An appropriate composite fading/shadowing channel model termed the Joint Fading and Two-path Shadowing (JFTS) model is adopted for the indoor wireless environmen...

The ergodic and outage channel capacity of different optimal and suboptimal combinations of transmit power and modulation rate adaptation strategies over a joint fading and two-path shadowing (JFTS) fading/shadowing channel is studied in this paper. Analytically tractable expressions for channel capacity are obtained, assuming perfect channel side...

In this paper analytical expressions for the channel capacity, channel cutoff rate and achievable bandwidth efficiency associated with M-ary signaling and Joint Fading and Two-path Shadowing (JFTS) fading/shadowing channel model that characterize mobility constrained indoor propagation scenarios are derived. Expressions for the bandwidth efficiency...

The ergodic and outage channel capacity of different optimal and suboptimal combinations of transmit power and modulation rate adaptation strategies over a Joint fading and Two-path Shadowing (JFTS) fading/shadowing channel is studied in this paper. Analytically tractable expressions for channel capacity are obtained assuming perfect channel side i...

The performance of Turbo coded Binary Phase Shift Keying (BPSK) over the Joint Fading and Two-path Shadowing (JFTS) environment is analyzed. Exact analytical expression for the Pairwise Error Probability (PEP) of Turbo codes over fully interleaved JFTS channels is presented using the proba-bility distribution of the squared independent and identica...

The performance of Turbo coded Binary Phase Shift Keying (BPSK) over the Joint Fading and Two-path Shadowing (JFTS) environment is analyzed. Exact analytical expression for the Pairwise Error Probability (PEP) of Turbo codes over fully interleaved JFTS channels is presented using the probability distribution of the squared independent and identical...

A new expression for the Cumulative Distribution Function (CDF) of the Joint Fading and Two-path Shadowing (JFTS) distribution is derived in this paper. The derived theoretical CDF expression is shown to agree with the experimental results. The CDF expression is used to derive an outage expression for non-diversity transmission which is then used t...

The performance of Binary Phase Shift Keying (BPSK) in a Joint fading and Two-path Shadowing (JFTS) environment is analyzed. Closed form expression for the exact Average Bit Error Rate (ABER) of coherent BPSK scheme is presented using the Moment Generating Function (MGF) of the JFTS distribution. Finally the coherent BPSK ABER of a wireless communi...

A new expression for the Cumulative Distribution Function (CDF) of the Joint Fading and Two-path Shadowing (JFTS) distribution is derived in this paper. The derived theo-retical CDF expression is shown to agree with the experimental results. The CDF expression is used to derive an outage expres-sion for non-diversity transmission which is then used...

The performance of Binary Phase Shift Keying (BPSK) in a Joint fading and Two-path Shadowing (JFTS) environment is analyzed. Closed form expression for the exact Average Bit Error Rate (ABER) of coherent BPSK scheme is presented using the Moment Generating Function (MGF) of the JFTS distribution. Finally the coherent BPSK ABER of a wireless communi...

New expressions for the joint moments, mean, variance and amount of fading (AF) of the Joint Fading and Two-path Shadowing (JFTS) distribution are derived in this letter. The derived expressions for theoretical mean and variance are shown to agree with the experimental results. The AF expression is used for comparing the severity of fading imparted...

This paper presents measurements and a propagation model for an indoor wireless LAN (WLAN) scenario that represents an open concept office or laboratory layout with few large obstacles to reflect and refract the transmitted signal. Most mobile WLAN users generally restrict their movements to a small area due to the inability of most WLANs to accomm...

New expressions for the joint moments, mean, vari-ance and amount of fading (AF) of the Joint Fading and Two-path Shadowing (JFTS) distribution are derived in this letter. The derived expressions for theoretical mean and variance are shown to agree with the experimental results. The AF expression is used for comparing the severity of fading imparte...

This paper presents measurements and a propaga-tion model for an indoor wireless LAN (WLAN) scenario that represents an open concept office or laboratory layout with few large obstacles to reflect and refract the transmitted signal. Most mobile WLAN users generally restrict their movements to a small area due to the inability of most WLANs to accom...

An efficient and high-performance semi-blind scheme is proposed for Multiple-Input Multiple-Output (MIMO) systems by iteratively combining channel estimation with K-Best Sphere Decoding (SD). To avoid the exponentially increasing com-plexity of Maximum Likelihood Detection (MLD) while achieving a near optimal MLD performance, K-best SD is considere...

We consider a mobile-to-mobile (M2M) communication scenario in a crowded city or suburban area, where each mobile terminal is surrounded by a group of scatterers. The non-line of sight (NLOS) communication channel is modelled as non-frequency selective double or cascaded Rayleigh distributed. Cooperative relaying with amplify and forward (AF) proto...

We consider a mobile-to-mobile (M2M) communication scenario in a crowded city or suburban area, where each mobile terminal is surrounded by a group of scatterers. The non-line of sight (NLOS) communication channel is modelled as non-frequency selective double or cascaded Rayleigh distributed. Cooperative relaying with amplify and forward (AF) proto...

We develop a semi-blind adaptive space-time shift keying (STSK) based multiple-input multiple-output system using a low-complexity iterative channel estimation and data detection scheme. We first employ the minimum number of STSK training blocks, which is related to the number of transmitter antennas, to obtain a rough least square chan- nel estima...