Local Wireless Communication Research Articles

ACStalk: Design and Implementation of An Access/Entry Control System using an Internet of Things (IoT) Platform

<p>An access/entry control system usually consists of many subsystems. These subsystems have different Application Programming Interfaces (APIs), but they need to be integrated and interacted well. Without a good integrated platform, the communications between subsystems will be very complicated. In addition, except user name and password, Radio Frequency Identification (RFID), and the human’s biometrics (e.g., fingerprint and face) are used to identify users. Wireless Local Area Network (WLAN), mobile communications (e.g. 4G/5G) and Bluetooth are adopted as the remote access technologies. In addition, with the COVID-19 pandemic, public health and personal safety are getting more concerns. People are required to wear personal protective equipment (PPE) in some special areas (e.g., barns and factories) to ensure the personal healthy and food’s safety. To identify the user and detect whether the PPE is correctly worn, this paper proposes an access/entry control system by using an Internet of Things (IoT) platform. Through the proposed IoT system architecture, different identification mechanisms and communication technologies can be adopted, and the messages can be exchanged between two mechanisms. This paper elaborates the architecture design of the IoT platform and discusses the implementation/deployment issues of the PPE detection by using machine learning mechanisms.</p> <p> </p>

Conformal Load-Bearing Antenna Structures-Mechanical Loading Considerations.

One of the important functions of antennas is to facilitate wireless communication. The IEEE 802.11 is part of the IEEE802 set of local area network technical standards, and specifies the media access control and physical layer protocols for implementing wireless local area network computer communication. The network physical layer protocol with a centre frequency of 2.4 GHz has a bandwidth of 22 MHz. A conformal load-bearing antenna structure (CLAS) facilitating this communication band that is tuned to 2.4 GHz must remain within this bandwidth. The aim of this paper is to investigate the effects of mechanical loading imposed on a load-bearing patch antenna with respect to its ability to remain within the specified bandwidth. The mechanical loading configurations considered include tensile, biaxial, and twisting. This paper will also report on the response of the antenna patch to the presence of a disbond between the metallised antenna and its substrate, which can arise due to fabrication anomalies and operational usage. This numerical work will assist in the design of experimental testing of the mechanical and electromagnetic properties of an embedded CLAS, which will ultimately be used to inform selection of appropriate regions to place patch antennas on load-bearing deformable surfaces.

A Quadrature Amplitude Modulation Receiver Model with Matched Filters

In this study, it is mathematically shown that the detector inputs obtained using the matched filters in the Quadrature Amplitude Modulation (QAM) receiver are the same expressions as those obtained using the integrators if a rectangular pulse is used in the transmitter and the channel is Additive White Gaussian Noise (AWGN). Under the assumption that there is a perfect synchronization between the transmitter and the receiver. QAM is intensively used at the present time for the data transmission on subchannels in orthogonal frequency-division multiplexing (OFDM) communication systems such as digital subscriber lines (DSLs) modems, wireless local area networks (WLANs) and cellular wireless communication systems (e.g. 4G LTE). Cyclic-prefix OFDM is deployed in 4G LTE systems and the rectangular pulse is used in the time domain to shape all subcarriers of OFDM.

Further results on the outer connected geodetic number of a graph

For a connected graph G of order at least two, an outer connected geodetic set S in a connected graph G is called a minimal outer connected geodetic set if no proper subset of S is an outer connected geodetic set of G. The upper outer connected geodetic number g+ oc(G) of G is the maximum cardinality of a minimal outer connected geodetic set of G. We determine bounds for it and find the upper outer connected geodetic number of some standard graphs. Some realization results on the upper outer connected geodetic number of a graph are studied. The proposed method can be extended to the identification of beacon vertices towards the network fault-tolerant in wireless local access network communication. Also, another parameter forcing outer connected geodetic number fog(G) of a graph G is introduced and several interesting results and realization theorem are proved.

Performance analysis of a new OCFHC/QCC vis‐a‐vis synchronous PC/OOC code using photon count approach

In this study, the performance of one-coincidence frequency hopping code/quadratic congruence code (OCFHC/QCC) has been analysed and compared with an existing code. The error probabilities of an eight-user optical code division multiple access (OCDMA) system are 4.7934 × 10 − 9 and 5.9497 × 10 − 10 for the synchronous prime code/optical orthogonal code (PC/OOC) and OCFHC/QCC, respectively, at the received power level −15 dBm and data rate 1 Gbps. The improvement in the performance is of the order of 10 − 1 which becomes better if the received power level increases beyond −15 dBm. In addition, the effect of variation in code weight, code length and number of wavelengths of the OCFHC/QCC code on the performance of the OCDMA system is also studied. OCFHC/QCC has a simple design methodology, flexibility in choosing the number of wavelengths, large cardinality and superior performance than the synchronous PC/OOC. Furthermore, the performance of the OCFHC/QCC is also analysed in the atmospheric channel. Based on the analysis, it is concluded that this code should be preferred for local area network, multicode keying, and wireless optical communication.

Performance analysis of a GI/D- $$MSP/1/\infty$$ M S P / 1 / ∞ queueing system under different service phase initiations

The main objective of this paper is to derive some analytic results concerning GI/D- $$MSP/1/\infty$$ queueing model in which customers arrive according to a discrete-time renewal process. We assume that the service process is correlated and its configuration is designed through discrete-time Markovian service process under different service phase initiations to start a busy period. The system-length distributions at various time epochs have been obtained by employing the matrix-geometric approach. An explicit closed form expression for the waiting-time distribution in the queue measured in slots has also been derived. Computational experiences with a variety of numerical results are discussed to show the effect of system parameters on the performance measures. This queueing model has potential applications in the domain of computer networks, telecommunication systems, and wireless local communication networks for evaluating the various system performances. An application of this type of queueing model in the domain of network coding in wireless communications is also discussed. This provides relevant information to the system analysts, researchers, and industry people who are interested to investigate congestion problems using queueing theory.

A Cyber-Enabled Mission-Critical System for Post-Flood Response: Exploiting TV White Space as Network Backhaul Links

A crucial problem in post-flood recovery actions is the ability to rapidly establish communication and collaboration among rescuers to conduct timely and effective search and rescue (SAR) mission given disrupted telecommunication infrastructure to support the service. Aimed at providing such proximity service (ProSe) for mission-critical data exchange in the post-flood environment, the majority of existing solutions rely heavily upon ad-hoc networking approaches, which suffer from restricted communication range and the limited scope of interaction. As an effort to broaden the ProSe coverage and expand integrated global-local information exchange in the post-flood SAR activities, this paper proposes a novel network architecture in the form of a cyber-enabled mission-critical system (CEMCS) for acquiring and communicating post-flood emergency data by exploiting TV white space spectrum as network backhaul links. The primary method of developing the proposed system builds upon a layered architecture of wireless local, regional and wide-area communications, and incorporates collaborative network components among these layers. The desirable functionalities of CEMCS are showcased through formulation and the development of an efficient global search strategy exploiting a wide range of collaboration among network agents. The simulation results demonstrate the capability of CEMCS to provide ProSe in the post-flood scenarios as reflected by reliable network performance (e.g., packet delivery ratio nearing 80%–90%) and the optimality of efficient search algorithm.

A Wideband V-Shaped Coplanar Patch Antenna for 2-6 GHz Designed for Energy Harvesting and Wireless Communications

This article portrays a compact wideband coplanar-fed V-shaped antenna. It has been designed for harvesting energy from wireless local area networks (IEEE 802.11) and other wireless communication systems covering the 2–6 GHz frequency band. The Structure of this antenna comprises a rectangular patch and an isosceles trapezoid. A V-shaped slot is introduced on the rectangular patch in order to perturb the surface current path which contributes to the formation of the wide-band characteristics. A trapezoid is inserted between the coplanar feed and the patch for the purpose of impedance matching and resonance shifting. A parametric study has been carried out to understand the effects of various dimensional parameters and to optimize the performance of the antenna. The measurement results which are in agreement with Ansoft HFSS simulation results, showed an agreeable bandwidth and satisfactory characteristics for omnidirectional radiation.

IEEE 802.11ay: Next-Generation 60 GHz Communication for 100 Gb/s Wi-Fi

The IEEE 802.11ad amendment to the 802.11 standard ratified in 2012 created the first multi- Gb/s Wi-Fi technology by using the large swath of unlicensed spectrum at the mm-Wave band. While enabling multi-Gb/s wireless local communications was a significant achievement, throughput and reliability requirements of new applications, such as augmented reality (AR)/virtual reality (VR) and wireless backhauling, exceed what 802.11ad can offer. For this reason, building upon IEEE 802.11ad, the IEEE 802.11 Task Group ay has recently defined new PHY and MAC specifications that enable 100 Gb/s communications through a number of technical advancements. In this article, we identify and describe the main design elements of IEEE 802.11ay, including MIMO, channel bonding, improved channel access, and enhanced beamforming training. For each of these elements, we discuss how their design is impacted by mm-Wave radio propagation characteristics and present enabling mechanisms defined in IEEE 802.11ay.

OVERLAPPED PHYSICAL CHANNELS LOAD MEASUREMENT IN 802.11 NETWORKS

Nowadays, with the increasing demand for wireless communication systems, basically Wireless Local Area Networks (WLANs) and Mobile communication systems, higher data rates with better Quality of Service (QoS) are required. While Heterogeneous Networks (Het-Nets) are under study toward 5G technology in mobile communication, WiFi Access Points (APs) are considered a potential layer within those multiple Radio Access Technologies (RATs). Significant network capacity gain can be achieved not only through aggressive reuse of spectrum across the multiple tiers in the network, but also through harnessing an additional spectrum in un-licensed bands by integrating WiFi in the network [1]. Different criteria should be investigated in order to allow both the WiFi APs and the end user to operate on the best suitable channel, where the basic one of those criteria is the “load” of the operating channels. We propose in this paper a novel and accurate algorithm for the estimation of WiFi 802.11n physical channels load through the observation of the non-overlapped channels and estimating as a result the load of the entire physical channels. Once the channels load is estimated using the proposed algorithm, the channel assignment based on the minimal load value is facilitated, thus providing faster response of an AP channel selection and faster end user connection for better Quality of Experience (QoE).

Design of ultra compact dual-band bandpass filter using L-shaped resonator

A compact dual-band microstrip bandpass filter (BPF) is presented for application at the frequencies 2.4 and 5.84 GHz. The proposed main resonator consists of two L-shaped resonators. To improve the upper-stopband of the proposed filter, modified U-Shaped resonators are accepted. The operation mechanism of the filter is investigated based on proffered equivalent-circuit model and transformation function. The sketched dual-band BPF attends the insertion loss less than 0.1 and 0.4 dB Also the return loss is 26 and 28 dB at 2.4 and 5.84, respectively. This proffered filter structure is proper for Bluetooth and wireless local area networks and other wireless communication systems. An overall good agreement between measured and simulated results is observed.

Optimal mobile device selection for round-robin data exchange via adaptive multi-criteria decision analysis

In recent years, exchanging data has become far easier with the rapidly growing popularity and increased mobility of mobile devices. However, data exchange between mobile devices is performed as a peer-to-peer communication. Each mobile device that serves as a candidate has a whole range of hardware statuses which may influence data exchange performance. Thus, the selection of a mobile device with sufficient computing resources to facilitate round-robin data exchange is an interesting process worth exploring. This study proposes an optimal mobile device selection approach for round-robin data exchange via the monitoring of the hardware status of each candidate device's system profile. A case study demonstrates the proposed approach, step by step. The experimental results show that the proposed approach can be used to improve round-robin data exchange performance. The contribution of this study is to provide an approach which selects an optimal candidate mobile device for round-robin data exchange in a local wireless communication network.

Self-Powered Wireless Sensor Applied to Gear Diagnosis Based on Acoustic Emission

Advanced sensing strategies in the industrial sector are becoming a valued technological answer to increase the performance and competitiveness. The development of enhanced sensing solutions considering both technology and monitoring requirements is, nowadays, subject of concern in the industrial maintenance field. In this context, this paper presents a novel self-powered wireless sensor applied to condition monitoring of gears. The proposed sensor is based on a modular architecture, offering multipoint sensing, local wireless communication, multisource energy harvesting, and embedded diagnosis algorithm for mechanical fractures detection based on acoustic emission analysis. The developments are complemented by means of a remote management interface, from which the user can configure the functionalities of the sensors, visualize the network status as well as analyze the diagnosis evolution. The sensor performance, in terms of power consumption and fault detection, has been analyzed by means of experimental results.

무선 LAN 시스템 성능개선에 관한 연구

본 논문은 4세대 무선 통신방식의 하나인 OFDM 기반의 60 GHz 무선 랜에서의 위상잡음의 영향에 관하여 논한다. 60 GHz 주파수 대역은 광대역 전송이 가능할 뿐만 아니라 실내 무선 환경에서의 무선 링크를 밀집 시킬 수 있다는 장점이 있다. 본 논문에서는 시스템 구현이 용이한 위상잡음 억제 알고리듬을 OFDM 기반의 60 GHz 무선 랜 시스템에 적용하고 이에 따른 성능을 SER 측면에서 분석하였다. 60 GHz 대역에서 발생하는 위상잡음 환경에서 위상잡음 억제 알고리듬을 적용한 경우, 그렇지 않은 경우에 비해 16-QAM, 64-QAM에서 각각 6 dB, 7.5 dB 정도의 SER 성능 향상을 보였다. We investigate the OFDM-based wireless LAN systems operating in the 60 GHz frequency band as part of the fourth-generation (4G) systems. The 60 GHz band is of much interest since this is the band in which a massive amount of spectral space has been allocated worldwide for dense wireless local communications. This paper gives an overview of 60 GHz band channel characteristics and an effect on phase noise. The performance of OFDM system is severely degraded by the local oscillator phase noise, which causes both common phase error and inter-carrier interference. In this paper, we apply phase noise suppression (PNS) algorithm that is easy for implementation to OFDM based 60 GHz wireless LAN system and analyze the SER performance. In case of using the PNS algorithm, SER performance is improved about 6 dB, 7.5 dB, respectively in 16, 64-QAM.

An Architecture Design for Wireless Authentication Security in Bluetooth Network

Bluetooth technology has become an integral part of this modern society. Bluetooth is a recently proposed protocol for local wireless communication and has become a de facto standard for short-range ad hoc radio connections. Security concern is one of the most important problems delaying the mass adoption of Bluetooth. Bluetooth communication range is categorized as high, medium and low depending upon power level. High range of Bluetooth communication is up to 91 meter, medium range is up to 9 meter and low range is up to 1 meter. Authentication and Encryption are the key security features that are used in Bluetooth communication. In this paper, we present architecture for authentication security of Bluetooth. The main goal of this paper is to design architecture of security for Bluetooth in real scenarios. In order to find out the major vulnerabilities in modern wireless Bluetoothenabled devices that has performed successfully for several attacks such as Unauthorized Direct Data Access (UDDA) and Man-in-the-Middle Attack (MITM). This form of authentication presents an interesting modeling challenge. We discuss the implications of this authentication security for typical Bluetooth usage scenarios.

Cooperative data download on the move in indoor hybrid (radio‐optical) WLAN‐VLC hotspot coverage

ABSTRACTIn this work, we study the performance of hybrid (radio‐optical) wireless local area network (WLAN)‐visible light communication (VLC) hotspot and compare its performance with stand‐alone VLC‐only or WLAN‐only hotspot cases. We consider data download on move scenario in an indoor environment for single‐user and for multi‐user cases. Short‐range spotlighting cell so‐called VLC hotspot is considered for high data rate region. On the other hand, WLAN hotspot is used for providing reliable connectivity and moderate data rate support. Throughput–distance relationships are developed both for WLAN and VLC to evaluate the performance of indoor environment by taking into account the radio and optical channel characteristics. The impact of the velocity of mobile user(s) and the number of VLC hotspots present in the considered service area are also considered on the performance of hybrid WLAN‐VLC hotspot. Simulations have been performed to evaluate the performance of such network for data downloading on move scenario by taking into account performance metrics such as file size, average connectivity and system throughput. Simulation results reveal that the considered hybrid WLAN‐VLC performs always better than stand‐alone VLC‐only or WLAN‐only hotspots both for single and multi‐user cases. Copyright © 2014 John Wiley & Sons, Ltd.

Small Antennas: Miniaturization Techniques and Applications

Although small antenna designs and miniaturization techniques have been widely studied in recent years, there are still many challenging issues in small antenna applications and research. In this special issue, several small antennas have been proposed and discussed for wireless local area networks (WLANs), UHF band, multiple-input-multipleoutput (MIMO), long-term-evolution (LTE), and other wireless communication applications. These designed antennas are not only small in size but also able to provide high performance to meet the practical engineering requirements with respect to the impedance bandwidth and the radiation patterns. On the other hand, two horn antennas with enhanced performance were developed for modern wireless communication applications. One of the horn antennas was designed to obtain high gain, which was realized by the integration of a horn antenna into a microstrip antenna. The other horn antennawas presented for ultra-wideband (UWB) applications by the combination of a TEM horn antenna with a Vivaldi antenna together. Both of the proposed improved horn antennas have been verified that they have low profile and good performance. In addition, several compact antennas have been proposed and investigated to provide high efficiency antenna and low SAR, which are suitable for on-body and mobile communications.Motivated by the rapid developments of the microwave imaging, a right angle-bent monopole antenna has been built to obtain small size and low profile for microwave tomographic imaging application. In addition, a compact frequency selective surface (FSS) has been proposed based on the square loop aperture element. The designed FSS can give high polarization stability, angle stability, and smaller size in comparison with the previously proposed FSS structures. Beyond that, frequency reconfigurable antennas have also been proposed in this special issue formultifunction communication applications. Since each narrowband system should be provided a different antenna, a reconfigurable antenna can be operated in several narrowband by controlling its reconfigurable states, which is flexible and can reduce the cost for practical engineering applications. A reconfigurable antenna has been investigated by using MEMS to realize multiband antenna. Furthermore, the MEMS technique has been also exploited for minimizing the antenna by means of tunable capacitors. As for the optimization method and measurement techniques, an orthogonal design method was proposed to optimize roughly designed antennas. Additionally, a wideband differential-mode current injection testing techniquewas also presented based on directional coupling device. In this special issue, two adaptive signal processing algorithms have been developed for sparse channel estimation and virtual array antenna applications. Both of the proposed adaptive algorithms can provide higher performance compared with previous classical algorithm and can be further developed for applying in the antenna arrays.

Channel characteristics of MIMO–WLAN communications at 60 GHz for various corridors

Abstract A comparison of 4 × 4 multiple-input multiple-output wireless local area network wireless communication characteristics for six different geometrical shapes is investigated. These six shapes include the straight shape corridor with rectangular cross section, the straight shape corridor with arched cross section, the curved shape corridor with rectangular cross section, the curved shape corridor with arched cross section, the L-shape corridor, and the T-shape corridor. The impulse responses of these corridors are computed by applying shooting and bouncing ray/image (SBR/Image) techniques along with inverse Fourier transform. By using the impulse response of these multipath channels, the mean excess delay, root mean square (RMS) delay spread for these six corridors can be obtained. Numerical results show that the capacity for the rectangular cross section corridors is smaller than those for the arched cross section corridors regardless of the shapes. And the RMS delay spreads for the T-and the L-shape corridors are greater than the other corridors.

멀티에이전트 시스템을 이용한 마이크로그리드 분산 지능형 관리시스템 파일럿 플랜트 개발

This paper describes the development of the pilot plant of distributed intelligent management system for a microgrid. For optimal control and management of microgrids, intelligent agents area applied to the microgrid management system. Each agent includes intelligent algorithms to make decisions on behalf of the corresponding microgrid entity such as distributed generators, local loads, and so on. To this end, each agent has its own resources to evaluate the system conditions by collecting local information and also communicating with other agents. This paper presents key features of the data communication and management of the developed pilot plant such as the construction of mesh network using local wireless communication techniques, the autonomous agent coordination schemes using plug-and-play functions of agents and contract net protocol (CNP) for decision-making. The performance of the pilot plant and developed algorithms are verified via real-time microgrid test bench based on hardware-in-the-loop simulation systems.

Wideband E-Shaped Microstrip Antenna for Wireless Sensor Networks

Problem statement: Wireless Sensor Networks (WSN) is currently receiving significant attention due to their unlimited potential. It is still very early in the lifetime of such systems and many research challenges exist, out of which one of the challenges is sensor processing and fusion under limited capacities, the most important component in sensor is its TX/RX antenna. Approach: For high-speed wireless local area networks and other wireless communication systems covering the 5.33-5.71 GHz frequency band. In this frequency band microstrip antennas have attracted with its low-profile in nature. Microstrip antenna was proposed to meet the challenges, which combines the advantages of compactness with the low cost and low profile of a patch antenna. Results: The key parameters governing the antenna optimization have been determined with the help of High Frequency Simulation Software (HFSS). As a consequence, 5.5GHz microstrip antenna with size 22×16×3.2 mm had been realized on duroid with 2.2. Conclusion: This combination of performance metrics is highly desirable for autonomous distributed sensor network applications where a small sensor node volume and excellent power efficiency are required.