Radio frequency identification (RFID) and wireless sensors networks (WSNs) are two fundamental pillars that enable the Internet of Things (IoT). RFID systems are able to identify and track devices, whilst WSNs cooperate to gather and provide information from interconnected sensors. This involves challenges, for example, in transforming RFID systems with identification capabilities into sensing and computational platforms, as well as considering them as architectures of wirelessly connected sensing tags. This, together with the latest advances in WSNs and with the integration of both technologies, has resulted in the opportunity to develop novel IoT applications. This paper presents a review of these two technologies and the obstacles and challenges that need to be overcome. Some of these challenges are the efficiency of the energy harvesting, communication interference, fault tolerance, higher capacities to handling data processing, cost feasibility, and an appropriate integration of these factors. Additionally, two emerging trends in IoT are reviewed: the combination of RFID and WSNs in order to exploit their advantages and complement their limitations, and wearable sensors, which enable new promising IoT applications.

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A review of IoT sensing applications and challenges using RFID and wireless sensor networks

Next Generation Wireless Lans 802 11n And 802 11ac

Virtual reality (VR) and augmented reality (AR) are overcoming the physical limits of real‐life using advances in devices and software. In particular, the recent restrictions in transportation from the coronavirus disease 2019 (COVID‐19) pandemic are making people more interested in these virtual experiences. However, to minimize the differences between artificial and natural perception, more human‐interactive and human‐like devices are necessary. The skin is the largest organ of the human body and interacts with the environment as the site of interfacing and sensing. Recent progress in skin electronics has enabled the use of the skin as the mounting object of functional devices and the signal pathway bridging humans and computers, with opening its potential in future VR and AR applications. In this review, the current skin electronics are summarized as one of the most promising device solutions for future VR/AR devices, especially focusing on the recent materials and structures. After defining and explaining VR/AR systems and the components, the advantages of skin electronics for VR/AR applications are emphasized. Next, the detailed functionalities of skin electronic devices, including the input, output, energy devices, and integrated systems, are reviewed for future VR/AR applications. [ABSTRACT FROM AUTHOR] Copyright of Advanced Functional Materials is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Skin Electronics: Next-Generation Device Platform for Virtual and Augmented Reality

Radio resource management (RRM) for future fifth-generation (5G) heterogeneous networks (HetNets) has emerged as a critical area due to the increased density of small-cell networks and radio access technologies. Recent research has mostly concentrated on resource management, including spectrum utilization and interference mitigation, but the complexities of these resources have been given little attention. This paper provides an overview of the issues arising from future 5G systems and highlights their importance. The different approaches used in recently published surveys categorizing RRM schemes are discussed, and the survey method is presented. We report on a survey of HetNet RRM schemes that have been studied recently, with a focus on the joint optimization of radio resource allocation with other mechanisms. These RRM schemes were subcategorized according to their optimization metrics and qualitatively analyzed and compared. An analysis of the complexity of RRM schemes in terms of implementation and computation is presented. Several potential scopes of research for future RRM in 5G HetNets are also identified.

Survey of Radio Resource Management in 5G Heterogeneous Networks

IEEE 802.11ax-2019 will replace both IEEE 802.11n-2009 and IEEE 802.11ac-2013 as the next high-throughput Wireless Local Area Network (WLAN) amendment. In this paper, we review the expected future WLAN scenarios and use-cases that justify the push for a new PHY/MAC IEEE 802.11 amendment. After that, we overview a set of new technical features that may be included in the IEEE 802.11ax-2019 amendment and describe both their advantages and drawbacks. Finally, we discuss some of the network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other on-going IEEE 802.11 amendments.

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IEEE 802.11ax: High-Efficiency WLANs

We are on the brink of a new era for the wireless telecommunications, an era that will change the way that business is done. The fifth generation (5G) systems will be the first realization in this new digital era where the various networks will be interconnected forming a unified system. With support for higher capacity as well as low-delay and machine-type communication services, the 5G networks will significantly improve performance over the current fourth generation (4G) systems and will also offer seamless connectivity to numerous devices by integrating different technologies, intelligence, and flexibility. In addition to ongoing 5G standardization activities and technologies under consideration in the Third Generation Partnership Project (3GPP), the Institute of Electrical and Electronic Engineers (IEEE)-based technologies operating on unlicensed bands, will also be an integral part of a 5G eco-system. Along with the 3GPP-based cellular technology, the IEEE standards and technologies are also evolving to keep pace with the user demands and new 5G services. In this paper, we provide an overview of the evolution of the cellular and Wi-Fi standards over the last decade with a particular focus on the Medium Access Control and Physical layers, and highlight the ongoing activities in both camps driven by the 5G requirements and use-cases.

The Race to 5G Era; LTE and Wi-Fi

This paper presents a dual-notch polarization and beam reconfigurable microstrip antenna. It uses parasitics which incorporate switches to steer its beam away from boresight and dual-notches which, again, incorporate switches to reconfigure between linear and circular polarization. The antenna is a low profile microstrip patch antenna which only uses a single feed, allowing it to be compact and simple in terms of its structure.

Beam and polarization reconfigurable microstrip antenna based on parasitics

A multiple parameter reconfigurable antenna is presented in this paper. The antenna is a microstrip patch which consists of a driven circular patch antenna and four circular parasitics. The reconfigurable operation of the antenna is realised by six embedded switches on the driven element and the parasitics. Two switches, embedded within the driven element are used to switch between circular polarisation (CP) and linear polarisation (LP). Whereas the embedded switches within the parasitics are used to alter the main beam direction. The antenna is capable of yielding CP radiation when the main beam is directed towards boresight. The antenna operates at 10.6 GHz. There is alignment between the −10 dB impedance bandwidth(BW) (6.6%) and the 3 dB axial ratio (AR) BW (1.4%) of the antenna. Furthermore, the main lobe gain is approximately constant for all steering angles.

Multiple parameter reconfigurable microstrip patch antenna

This paper presents a novel antenna which represents an alternative to conventional phased array antennas. The novel antenna offers three important advantages in comparison with a conventional phased array antenna. These advantages are as follows: i) it is able to steer the beam to relatively wide angles (±31°), ii) it maintains low side-lobe level of < −10 dB across the steering range and iii) it achieves gain stability over the steering range. It also demonstrates relatively high gain (≈ 15 dB) to meet the demand of high capacity and long range in wireless communication applications. The proposed array antenna involves the use of parasitic elements and phase shifters.

Side lobe level reduction for beam steerable antenna design

Millimetre wave beam and polarization reconfigurable antennas for future wireless communications 
are investigated in this thesis. The millimetre wave frequency spectrum 
has recently attracted large attention from researchers and the industry of wireless communications.
Millimetre wave frequencies is considered to be the frequency spectrum 
between 30 GHz and 300 GHz. However, the industry considers the spectrum above 10 
GHz as millimetre wave, due to the fact that it shows similar propagation characteristics 
with the spectrum above 30 GHz. The aforementioned spectrum of frequencies
offers a lot of advantages compared to lower frequency spectrum, due to the fact that 
it offers large and mostly unexploited bandwidths. The need for very high data rates,
in future wireless communications, increases the need for bandwidth. Millimetre wave 
frequencies can be used to fulfill future bandwidth demands.
Although millimeter wave frequencies offer several advantages and good potential for 
future wireless communications, they also impose several challenges. This thesis discusses 
the need for highly directive and beam reconfigurable antennas for such high 
frequencies. It also discusses how an antenna design can benefit from being circularly 
polarised for several wireless communication applications and how antennas for future
wireless communications must be able to reconfigure several parameters, without compromising 
the performance, cost and size, giving the 
exibility to a wireless terminal 
to operate in several different modes.
This thesis proposes novel reconfigurable antennas for portable devices, which can be 
used at millimetre wave frequencies, and which offer high gain, wide steering range, low 
scan loss and multi-parameter reconfigurability; essential characteristics that antennas 
designed for future wireless communications should offer.

Marion Allayioti

Papers

The Race to 5G Era; LTE and Wi-Fi

Beam and polarization reconfigurable microstrip antenna based on parasitics

Multiple parameter reconfigurable microstrip patch antenna

Side lobe level reduction for beam steerable antenna design

Beam reconfigurable microstrip antennas based on parasitics with linear and circular polarisation capability.