74 research outputs found
RF-Powered Cognitive Radio Networks: Technical Challenges and Limitations
The increasing demand for spectral and energy efficient communication
networks has spurred a great interest in energy harvesting (EH) cognitive radio
networks (CRNs). Such a revolutionary technology represents a paradigm shift in
the development of wireless networks, as it can simultaneously enable the
efficient use of the available spectrum and the exploitation of radio frequency
(RF) energy in order to reduce the reliance on traditional energy sources. This
is mainly triggered by the recent advancements in microelectronics that puts
forward RF energy harvesting as a plausible technique in the near future. On
the other hand, it is suggested that the operation of a network relying on
harvested energy needs to be redesigned to allow the network to reliably
function in the long term. To this end, the aim of this survey paper is to
provide a comprehensive overview of the recent development and the challenges
regarding the operation of CRNs powered by RF energy. In addition, the
potential open issues that might be considered for the future research are also
discussed in this paper.Comment: 8 pages, 2 figures, 1 table, Accepted in IEEE Communications Magazin
Energy Detection of Unknown Signals over Cascaded Fading Channels
Energy detection is a favorable mechanism in several applications relating to
the identification of deterministic unknown signals such as in radar systems
and cognitive radio communications. The present work quantifies the detrimental
effects of cascaded multipath fading on energy detection and investigates the
corresponding performance capability. A novel analytic solution is firstly
derived for a generic integral that involves a product of the Meijer
function, the Marcum function and arbitrary power terms. This solution
is subsequently employed in the derivation of an exact closed-form expression
for the average probability of detection of unknown signals over *Rayleigh
channels. The offered results are also extended to the case of square-law
selection, which is a relatively simple and effective diversity method. It is
shown that the detection performance is considerably degraded by the number of
cascaded channels and that these effects can be effectively mitigated by a
non-substantial increase of diversity branches.Comment: 12 page
Internet of Mirrors for Connected Healthcare and Beauty: A Prospective Vision
With the shift towards smart objects and automated services in many
industries, the health and beauty industries are also becoming increasingly
involved in AI-driven smart systems. There is a rising market demand for
personalised services and a need for unified platforms in many sectors,
specifically the cosmetics and healthcare industries. Alongside this rising
demand, there are two major gaps when considering the integration of autonomous
systems within these sectors. Firstly, the existing smart systems in the
cosmetics industry are limited to single-purpose products and the employed
technologies are not widespread enough to support the growing consumer demand
for personalisation. Secondly, despite the rise of smart devices in healthcare,
the current state-of-the-art services do not fulfil the accessibility demands
and holistic nature of healthcare. To bridge these gaps, we propose integrating
autonomous systems with health and beauty services through a unified visual
platform coined as the Internet-of-Mirrors (IoM), an interconnected system of
smart mirrors with sensing and communication capabilities where the smart
mirror functions as an immersive visual dashboard to provide personalised
services for health and beauty consultations and routines. We aim to present an
overview of current state-of-the-art technologies that will enable the
development of the IoM as well as provide a practical vision of this system
with innovative scenarios to give a forward-looking vision for assistive
technologies. We also discuss the missing capabilities and challenges the
development of the IoM would face and outline future research directions that
will support the realisation of our proposed framework.Comment: 21 pages, 6 figure
Performance analysis of SWIPT relay networks with noncoherent modulation
In this paper, we investigate the performance of noncoherent modulation in simultaneous wireless information and power transfer (SWIPT) relay networks. Noncoherent modulation schemes eliminate the need for instantaneous channel state information (CSI) estimation, and therefore, minimise the overall energy consumption of the network. In particular, we adopt a moments-based approach to develop a comprehensive novel analytical framework for the analysis of the outage probability, achievable throughput, and average symbol error rate (ASER) of a dual-hop SWIPT relay system considering the time switching (TS) and power splitting (PS) receiver architectures. In addition, through the derivation of new asymptotic analytical results for the outage probability and ASER, we analytically demonstrate that the diversity order of the considered system is non-integer less than 1 in the high SNR regime. Our results show that there is a unique value for the PS ratio that minimises the outage probability of the system, while this is not the case for the TS protocol. We also demonstrate that, in terms of system throughput, the TS relaying scheme is superior to the PS relaying scheme at lower SNR values. An extensive Monte Carlo simulation study is presented to corroborate the proposed analytical model
Performance of reconfigurable intelligent surfaces in the presence of generalized Gaussian noise
In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assisted communications, under the assumption of generalized Gaussian noise (GGN), over Rayleigh fading channels. Specifically, we consider an RIS, equipped with N reflecting elements, and derive a novel closed-form expression for the symbol error rate (SER) of arbitrary modulation schemes. The usefulness of the derived new expression is that it can be used to capture the SER performance in the presence of special additive noise distributions such as Gamma, Laplacian, and Gaussian noise. These special cases are also considered and their associated asymptotic SER expressions are derived, and then employed to quantify the achievable diversity order of the system. The theoretical framework is corroborated by numerical results, which reveal that the shaping parameter of the GGN (α) has a negligible effect on the diversity order of RIS-assisted systems, particularly for large α values. Accordingly, the maximum achievable diversity order is determined by N
Performance analysis of SWIPT relaying systems in the presence of impulsive noise
We develop an analytical framework to characterize the effect of impulsive noise on the performance of relay-assisted simultaneous wireless information and power transfer (SWIPT) systems. We derive novel closed-form expressions for the pairwise error probability (PEP) considering two variants based on the availability of channel state information (CSI), namely, blind re-laying and CSI-assisted relaying. We further consider two energy harvesting (EH) techniques, i.e., instantaneous EH (IEH) and average EH (AEH). Capitalizing on the derived analytical results, we present a detailed numerical investigation of the diversity order for the underlying scenarios under the impulsive noise assumption. For the case when two relays and the availability of a direct link, it is demonstrated that the considered SWIPT system with blind AEH-relaying is able to achieve an asymptotic diversity order of less than 3, which is equal to the diversity order achieved by CSI-assisted IEH-relaying. This result suggests that, by employing the blind AEH relaying, the power consumption of the network can be reduced, due to eliminating the need of CSI estimation. This can be achieved without any performance loss. Our results further show that placing the relays close to the source can significantly mitigate the detrimental effects of impulsive noise. Extensive Monte Carlo simulation results are presented to validate the accuracy of the proposed analytical framework
Performance of reconfigurable intelligent surfaces in the presence of generalized Gaussian noise
In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assisted communications, under the assumption of generalized Gaussian noise (GGN), over Rayleigh fading channels. Specifically, we consider an RIS, equipped with N reflecting elements, and derive a novel closed-form expression for the symbol error rate (SER) of arbitrary modulation schemes. The usefulness of the derived new expression is that it can be used to capture the SER performance in the presence of special additive noise distributions such as Gamma, Laplacian, and Gaussian noise. These special cases are also considered and their associated asymptotic SER expressions are derived, and then employed to quantify the achievable diversity order of the system. The theoretical framework is corroborated by numerical results, which reveal that the shaping parameter of the GGN (α) has a negligible effect on the diversity order of RIS-assisted systems, particularly for large α values. Accordingly, the maximum achievable diversity order is determined by N
A Prospective Look: Key Enabling Technologies, Applications and Open Research Topics in 6G Networks
The fifth generation (5G) mobile networks are envisaged to enable a plethora
of breakthrough advancements in wireless technologies, providing support of a
diverse set of services over a single platform. While the deployment of 5G
systems is scaling up globally, it is time to look ahead for beyond 5G systems.
This is driven by the emerging societal trends, calling for fully automated
systems and intelligent services supported by extended reality and haptics
communications. To accommodate the stringent requirements of their prospective
applications, which are data-driven and defined by extremely low-latency,
ultra-reliable, fast and seamless wireless connectivity, research initiatives
are currently focusing on a progressive roadmap towards the sixth generation
(6G) networks. In this article, we shed light on some of the major enabling
technologies for 6G, which are expected to revolutionize the fundamental
architectures of cellular networks and provide multiple homogeneous artificial
intelligence-empowered services, including distributed communications, control,
computing, sensing, and energy, from its core to its end nodes. Particularly,
this paper aims to answer several 6G framework related questions: What are the
driving forces for the development of 6G? How will the enabling technologies of
6G differ from those in 5G? What kind of applications and interactions will
they support which would not be supported by 5G? We address these questions by
presenting a profound study of the 6G vision and outlining five of its
disruptive technologies, i.e., terahertz communications, programmable
metasurfaces, drone-based communications, backscatter communications and
tactile internet, as well as their potential applications. Then, by leveraging
the state-of-the-art literature surveyed for each technology, we discuss their
requirements, key challenges, and open research problems
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