Showing papers on "Wi-Fi array published in 2015"

Wireless powered communication: opportunities and challenges

Abstract: The performance of wireless communication is fundamentally constrained by the limited battery life of wireless devices, the operations of which are frequently disrupted due to the need of manual battery replacement/recharging. The recent advance in RF-enabled wireless energy transfer (WET) technology provides an attractive solution named wireless powered communication (WPC), where the wireless devices are powered by dedicated wireless power transmitters to provide continuous and stable microwave energy over the air. As a key enabling technology for truly perpetual communications, WPC opens up the potential to build a network with larger throughput, higher robustness, and increased flexibility compared to its battery-powered counterpart. However, the combination of wireless energy and information transmissions also raises many new research problems and implementation issues that need to be addressed. In this article, we provide an overview of stateof- the-art RF-enabled WET technologies and their applications to wireless communications, highlighting the key design challenges, solutions, and opportunities ahead.

A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends

Abstract: This paper examines the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state-of-the-art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. We also introduce the family of various jamming attacks and their counter-measures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

Application of smart antenna technologies in simultaneous wireless information and power transfer

Abstract: Simultaneous wireless information and power transfer (SWIPT) is a promising solution to increase the lifetime of wireless nodes and hence alleviate the energy bottleneck of energy constrained wireless networks. As an alternative to conventional energy harvesting techniques, SWIPT relies on the use of radio frequency signals, and is expected to bring some fundamental changes to the design of wireless communication networks. This article focuses on the application of advanced smart antenna technologies to SWIPT, including multiple-input multiple-output and relaying techniques. These smart antenna technologies have the potential to significantly improve the energy efficiency and also the spectral efficiency of SWIPT. Different network topologies with single and multiple users are investigated, along with some promising solutions to achieve a favorable trade-off between system performance and complexity. A detailed discussion of future research challenges for the design of SWIPT systems is also provided.

Wireless Sensor Networks for Condition Monitoring in the Railway Industry: A Survey

Abstract: In recent years, the range of sensing technologies has expanded rapidly, whereas sensor devices have become cheaper. This has led to a rapid expansion in condition monitoring of systems, structures, vehicles, and machinery using sensors. Key factors are the recent advances in networking technologies such as wireless communication and mobile ad hoc networking coupled with the technology to integrate devices. Wireless sensor networks (WSNs) can be used for monitoring the railway infrastructure such as bridges, rail tracks, track beds, and track equipment along with vehicle health monitoring such as chassis, bogies, wheels, and wagons. Condition monitoring reduces human inspection requirements through automated monitoring, reduces maintenance through detecting faults before they escalate, and improves safety and reliability. This is vital for the development, upgrading, and expansion of railway networks. This paper surveys these wireless sensors network technology for monitoring in the railway industry for analyzing systems, structures, vehicles, and machinery. This paper focuses on practical engineering solutions, principally, which sensor devices are used and what they are used for; and the identification of sensor configurations and network topologies. It identifies their respective motivations and distinguishes their advantages and disadvantages in a comparative review.

Power receptacle wireless access point devices for networked living and work spaces

Abstract: Described herein are power receptacle wireless access point (AP) devices that may be used as part of a networked (smart) living and work space. These power receptacle wireless AP devices may be wall-mounted and/or retrofitted over existing electrical outlets or light switches, for providing wireless access to a room or region of a room. The power receptacle wireless AP device may connect via power line communication to a data connection.

Mininet-WiFi: Emulating software-defined wireless networks

Abstract: As the density of wireless networks continues to grow with more clients, more base stations, and more traffic, designing cost-effective wireless solutions with efficient resource usage and ease to manage is an increasing challenging task due to the overall system complexity. A number of vendors offer scalable and high-performance wireless networks but at a high cost and commonly as a single-vendor solution, limiting the ability to innovate after roll-out. Recent Software-Defined Networking (SDN) approaches propose new means for network virtualization and programmability advancing the way networks can be designed and operated, including user-defined features and customized behaviour even at run-time. However, means for rapid prototyping and experimental evaluation of SDN for wireless environments are not yet available. This paper introduces Mininet-WiFi as a tool to emulate wireless OpenFlow/SDN scenarios allowing high-fidelity experiments that replicate real networking environments. Mininet-WiFi augments the well-known Mininet emulator with virtual wireless stations and access points while keeping the original SDN capabilities and the lightweight virtualization software architecture. We elaborate on the potential applications of Mininet-Wifi and discuss the benefits and current limitations. Two use cases based on IEEE 802.11 demonstrate available functionality in our open source developments.

Recent Advances in Industrial Wireless Sensor Networks Toward Efficient Management in IoT

Abstract: With the accelerated development of Internet-of-Things (IoT), wireless sensor networks (WSNs) are gaining importance in the continued advancement of information and communication technologies, and have been connected and integrated with the Internet in vast industrial applications. However, given the fact that most wireless sensor devices are resource constrained and operate on batteries, the communication overhead and power consumption are therefore important issues for WSNs design. In order to efficiently manage these wireless sensor devices in a unified manner, the industrial authorities should be able to provide a network infrastructure supporting various WSN applications and services that facilitate the management of sensor-equipped real-world entities. This paper presents an overview of industrial ecosystem, technical architecture, industrial device management standards, and our latest research activity in developing a WSN management system. The key approach to enable efficient and reliable management of WSN within such an infrastructure is a cross-layer design of lightweight and cloud-based RESTful Web service.

Wireless communications in the era of big data

Abstract: The rapidly growing wave of wireless data service is pushing against the boundary of our communication network's processing power. The pervasive and exponentially increasing data traffic present imminent challenges to all aspects of wireless system design, such as spectrum efficiency, computing capabilities, and fronthaul/backhaul link capacity. In this article, we discuss the challenges and opportunities in the design of scalable wireless systems to embrace the big data era. On one hand, we review the state-of-the-art networking architectures and signal processing techniques adaptable for managing big data traffic in wireless networks. On the other hand, instead of viewing mobile big data as an unwanted burden, we introduce methods to capitalize on the vast data traffic, for building a big-data-aware wireless network with better wireless service quality and new mobile applications. We highlight several promising future research directions for wireless communications in the mobile big data era.

Design and Implementation of Smart Home Control Systems Based on Wireless Sensor Networks and Power Line Communications

Abstract: Wireless sensor networks (WSNs) and power line communications (PLCs) are used in this work to implement a smart home control network. The goals are to reduce the impact of wireless interference on a smart home control network and unnecessary energy consumption of a smart home. An isolated WSN with one coordinator, which is integrated into the PLC transceiver, is established in each room. The coordinator is responsible for transferring environmental parameters obtained by WSNs to the management station via PLCs. The control messages for home appliances are directly transferred using PLCs rather than WSNs. According to the experimental results, the impact of wireless interference on the proposed smart home control network is substantially mitigated. Additionally, a smart control algorithm for lighting systems and an analysis of the illumination of a fluorescent lamp were presented. The energy saving of lighting systems relative to those without smart control was evaluated. Numerical results indicate that the electricity consumption on a sunny or cloudy day can be reduced by at least 40% under the smart control. Moreover, a prototype for the proposed smart home control network with the smart control algorithm was implemented. Experimental tests demonstrate that the proposed system for smart home control networks is practically feasible and performs well.

Method and apparatus for adjusting wireless communications

Abstract: Aspects of the subject disclosure may include, for example, a method for adjusting an operational parameter of electromagnetic waves supplied to a feed point of a dielectric antenna to modify a beamwidth of far-field wireless signals generated by the dielectric antenna, the electromagnetic waves propagating along the feed point without an electrical return path, detecting that the beamwidth of the far-field wireless signals needs to be adjusted to improve a reception of the far-field wireless signals by a remote system, and adjusting the operational parameter of the electromagnetic waves to adjust the beamwidth of the far-field wireless signals. Other embodiments are disclosed.

Information-centric network function virtualization over 5g mobile wireless networks

Abstract: Wireless network virtualization and information-centric networking (ICN) are two promising techniques in software-defined 5G mobile wireless networks. Traditionally, these two technologies have been addressed separately. In this paper we show that integrating wireless network virtualization with ICN techniques can significantly improve the end-to-end network performance. In particular, we propose an information- centric wireless network virtualization architecture for integrating wireless network virtualization with ICN. We develop the key components of this architecture: radio spectrum resource, wireless network infrastructure, virtual resources (including content-level slicing, network-level slicing, and flow-level slicing), and informationcentric wireless virtualization controller. Then we formulate the virtual resource allocation and in-network caching strategy as an optimization problem, considering the gain of not only virtualization but also in-network caching in our proposed information-centric wireless network virtualization architecture. The obtained simulation results show that our proposed information-centric wireless network virtualization architecture and the related schemes significantly outperform the other existing schemes.

Autonomous robot-assisted indoor wireless coverage characterization platform

Abstract: A wireless coverage characterization platform uses an autonomous vehicle or robot, such as an unmanned aerial vehicle or other small robot, to autonomously collect key wireless coverage parameters for an indoor environment. One or more vehicles or robots are equipped with integrated simultaneous localization and mapping sensors as well as wireless signal measurement sensors. As a vehicle traverses the indoor environment, on-board processing components process the sensor measurement data to simultaneously build an indoor map of the environment and to learn the wireless coverage characteristics of the environment incrementally. The vehicle's navigation system guides the vehicle through the environment based on the sensor measurements and the learned indoor map until a complete map of the wireless signal strength at all locations throughout the environment is obtained. The system can identify areas of weak wireless coverage or interference sources and recommend access point device locations based on results of the survey.

Enhancing wireless secrecy via cooperation: signal design and optimization

Abstract: Physical layer security, or information-theoretic security, has attracted considerable attention recently, due to its potential to enhance the transmission secrecy of wireless communications. Various secrecy signaling and coding schemes have been designed at the physical layer of wireless systems to guarantee confidentiality against information leakage to unauthorized receivers, among which the strategy based on the idea of node cooperation is promising. This article provides an overview of the recent research on enhancing wireless transmission secrecy via cooperation. We take a signal processing perspective and focus on the secrecy signal design and optimization techniques to increase secrecy performance. We also propose some future research directions on this topic.

Method of handling wireless charging authentication

Abstract: A method of handling wireless charging authentication for an electronic device of a wireless charging system includes sending a first message to a controller of the wireless charging system to notify the controller that an authentication is required by a wireless charger of the wireless charging system; receiving a second message including authentication information from the controller; and sending a third message including the authentication information to the wireless charger, in order to satisfy the authentication.

Wireless power transfer method, apparatus and system

Abstract: A wireless power transfer method for a wireless power transfer apparatus using full and half-bridge inverter topologies includes detecting whether or not a wireless power receiver (200) is present within a range of power being transferrable in a wireless manner, transmitting a detection signal to the wireless power receiver (200), receiving at least one of identification information and setting information from the wireless power receiver (200), receiving a control error packet from the wireless power receiver (200), and controlling an amount of power to be transferred by using the combination of a driving frequency, a duty cycle or a power signal phase to the full or half-bridge inverter.

Social Network Aware Device-to-Device Communication in Wireless Networks

Abstract: Device-to-device (D2D) communication is seen as a major technology to overcome the imminent wireless capacity crunch and to enable new application services. In this paper, a novel social-aware approach for optimizing D2D communication by exploiting two layers, namely the social network layer and the physical wireless network layer, is proposed. In particular, the physical layer D2D network is captured via the users' encounter histories. Subsequently, an approach, based on the so-called Indian Buffet Process, is proposed to model the distribution of contents in the users' online social networks. Given the social relations collected by the base station, a new algorithm for optimizing the traffic offloading process in D2D communications is developed. In addition, the Chernoff bound and approximated cumulative distribution function (cdf) of the offloaded traffic are derived and the validity of the bound and cdf is proven. Simulation results based on real traces demonstrate the effectiveness of our model and show that the proposed approach can offload the network's traffic successfully.

Wireless charger networking for mobile devices: fundamentals, standards, and applications

Abstract: Wireless charging is a technique of transmitting power through an air gap to an electrical device for the purpose of energy replenishment. Recently, wireless charging technology has significantly advanced in terms of efficiency and functionality. This article first presents an overview and fundamentals of wireless charging. We then provide the review of standards, that is, Qi and the Alliance for Wireless Power, and highlight their communication protocols. Next, we propose a novel concept of wireless charger networking that allows chargers to be connected to facilitate information collection and control. We demonstrate the application of the wireless charger network in user-charger assignment, which clearly shows the benefit in terms of reduced costs for users to identify the best chargers to replenish energy for their mobile devices.

Wireless power transmitter and method for controlling wireless power transmitter

Abstract: Provided is a method for controlling a wireless power transmitter transmitting wireless power to at least one wireless power receiver. The method for controlling a wireless power transmitter, according to the present invention, can comprise the steps of: receiving information related to a wireless power receiver from at least one of each of the wireless power receivers; and controlling each of a plurality of power transmitting units included in the wireless power transmitter on the basis of the information related to the wireless power receiver.

Physical layer security in wireless cooperative relay networks: state of the art and beyond

Abstract: Cooperative relaying is an effective method of increasing the range and reliability of wireless networks, and several relaying strategies have been adopted in major wireless standards. Recently, cooperative relaying has also been considered in the context of PHY security, which is a new security paradigm to supplement traditional cryptographic schemes that usually handle security at the upper layers. In wireless PHY security, relay nodes can be used to exploit the physical layer properties of wireless channels in order to support a secured transmission from a source to a destination in the presence of one or more eavesdroppers. While some breakthroughs have been made in this emerging research area, to date, the problem of how to effectively adopt advanced relaying protocols to enhance PHY security is still far from being fully understood. In this article, we present a comprehensive summary of current state-of-theart PHY security concepts in wireless relay networks. A case study is then provided to quantify the benefits of power allocation and relay location for enhanced security. We finally outline important future research directions in relaying topologies, full-duplex relaying, and cross-layer design that can ignite new interests and ideas on the topic.

Wireless virtualization for next generation mobile cellular networks

Abstract: With wireless virtualization, the overall expenses of mobile cellular network deployment and operation can be significantly reduced by abstracting and sharing infrastructure and radio spectrum resources. Moreover, wireless virtualization can provide easier migration to newer products or technologies by isolating part of the network. Despite the potential vision of wireless virtualization, several significant research challenges remain. In this article, we provide a brief survey on some of the work that has been done on wireless virtualization in cellular networks. We also present the motivations and business models of wireless virtualization. Furthermore, we present a framework that enables wireless virtualization. In addition, we discuss a number of challenges that need to be addressed for the deployment of wireless virtualization in next generation mobile cellular networks.

Multi-antenna relay aided wireless physical layer security

Abstract: With the growing popularity of mobile Internet, providing secure wireless services has become a critical issue. Physical layer security (PHY-security) has been recognized as an effective means to enhance wireless security by exploiting wireless medium characteristics, for example, fading, noise, and interference. A particularly interesting PHY-security technology is cooperative relay due to the fact that it helps to provide distributed diversity and shorten access distance. This article offers a tutorial on various multi-antenna relaying technologies to improve security at physical layer. The state-of-the-art research results on multi-antenna relay aided PHY-security as well as some secrecy performance optimization schemes are presented. In particular, we focus on large-scale MIMO relaying technology, which is effective in tackling various challenging issues for implementing wireless PHY-security, such as short-distance interception without eavesdropper CSI and with imperfect legitimate CSI. Moreover, the future directions are identified for further enhancement of secrecy performance.

Using Cognitive Radio for Interference-Resistant Industrial Wireless Sensor Networks: An Overview

Abstract: Industrial wireless sensor networks (IWSNs) have to contend with environments that are usually harsh and time-varying. Industrial wireless technology, such as WirelessHART and ISA 100.11a, also operates in a frequency spectrum utilized by many other wireless technologies. With wireless applications rapidly growing, it is possible that multiple heterogeneous wireless systems would need to operate in overlapping spatiotemporal regions. Interference such as noise or other wireless devices affects connectivity and reduces communication link quality. This negatively affects reliability and latency, which are core requirements of industrial communication. Building wireless networks that are resistant to noise in industrial environments and coexisting with competing wireless devices in an increasingly crowded frequency spectrum is challenging. To meet these challenges, we need to consider the benefits that approaches finding success in other application areas can offer industrial communication. Cognitive radio (CR) methods offer a potential solution to improve resistance of IWSNs to interference. Integrating CR principles into the lower layers of IWSNs can enable devices to detect and avoid interference, and potentially opens the possibility of utilizing free radio spectrum for additional communication channels. This improves resistance to noise and increases redundancy in terms of channels per network node or adding additional nodes. In this paper, we summarize CR methods relevant to industrial applications, covering CR architecture, spectrum access and interference management, spectrum sensing, dynamic spectrum access (DSA), game theory, and CR network (CRN) security.

Wireless Power Systems for Mobile Devices Supporting Inductive and Resonant Operating Modes

Abstract: We demonstrate a family of wireless power devices that operate in a variety of operating modes. A multimode wireless power receiver unit (PRU) allows a mobile device to charge from any one of three wireless power standards: Qi, Power Matters Alliance, or Rezence. A coil arrangement and matching network is introduced that is resonant in both 6.78-MHz and 100-kHz bands, allowing the same power conversion circuitry to operate in either mode. The multi-mode PRU converts 5 W of ac power to a regulated 5-V output with an efficiency of up to 83% in Rezence mode and up to 86% in Qi mode. A wireless charging power transfer unit (PTU) using the Rezence specification charges three such PRUs at a power level of 5 W each with a power transfer efficiency of 66%. An in-band communications protocol provides enhanced capabilities to the Rezence system. Multiple layers of encoding ensure reliable delivery of messages under difficult channel conditions. Another PTU design allows the same receiver to charge through a table of 30-mm thickness while maintaining the in-band communications link. We show that a wide variety of multimode devices are possible, enabling widespread adoption of wireless power even in the absence of a single unified standard.

Methods and systems for data communications

Abstract: A wireless communication device of a vehicle system includes one or more antennas configured to be disposed onboard a first vehicle of the vehicle system, a first modem configured to be disposed onboard the first vehicle and to communicate a first wireless signal to one or more of a second vehicle of the vehicle system or an off-board device using the one or more antennas, and a second modem configured to be disposed onboard the first vehicle and to communicate a second wireless signal to the one or more of the second vehicle or the off-board device using the one or more antennas. The first modem is configured to communicate the first wireless signal via a first type of wireless communication link and the second modem is configured to communicate the second wireless signal via a different, second type of wireless communication link.

Antenna array calibration for wireless charging

Abstract: Antenna array calibration for wireless charging is disclosed. A wireless charging system is provided and configured to calibrate antenna elements in a wireless charging station based on a feedback signal provided by a wireless charging device. The antenna elements in the wireless charging station transmit wireless radio frequency (RF) charging signals to the wireless charging device. The wireless charging device provides the feedback signal to the wireless charging station to indicate total RF power in the wireless RF charging signals. The wireless charging station is configured to adjust transmitter phases associated with the antenna elements based on the feedback signal until the total RF power in the wireless RF charging signals is maximized. By calibrating the antenna elements based on the feedback signal, it is possible to achieve phase coherency among the antenna elements without requiring factory calibration.

Smart home for elderly care, based on Wireless Sensor Network

Abstract: The population of elder people is growing rapidly and these days many of them have to stay alone, independently instead of old age homes. With increasing age, people tend to forget things which may create safety problems for them. In this paper, it is proposed to develop a Wireless Sensor Network based smart home system for such elder people to help them ease their work and provide them safe, sound and secure living. A Wireless Sensor Network (WSN) is comprised of a large number of sensor nodes that are deployed in an unattended and remote environment to measure a few physiological parameters. The recent development in WSNs is the concept of Smart Homes. Smart homes integrate many devices that can sense the required parameters and control the characteristics of the home. The great progress in the industry standards and installation of lightweight wireless networking hardware over a period of time has proved ZigBee to be well suited for Smart homes and automation systems. ZigBee is a low cost, low power, less complex wireless standard. In this paper, sensors like temperature sensor, LPG sensor, Contact sensor are proposed to be deployed for fire detection, gas leakage detection and determination of whether any door is closed or open, respectively. LabVIEW is used as a graphical user interface. In case of any emergency, a warning message will be generated, and played through a loudspeaker for the user to take notice of the same and an SMS will be sent to the caregiver using GSM modem to take preventive action.

Resource allocation in wireless networks with RF energy harvesting and transfer

Abstract: RF energy harvesting and transfer techniques have recently become alternative methods to power the next generation of wireless networks. As this emerging technology enables proactive replenishment of wireless devices, it is advantageous in supporting applications with QoS requirements. This article focuses on the resource allocation issues in wireless networks with RF energy harvesting capability, referred to as RF-energy harvesting networks (RF-EHNs). First we present an overview of the RF-EHNs, followed by a review of a variety of issues regarding resource allocation. Then we present a case study of designing in the receiver operation policy, which is of paramount importance in RF-EHNs. We focus on QoS support and service differentiation, which have not been addressed in previous literature. We also outline open research directions.

Frequency division multiplexing for wireless power providers

Abstract: Disclosed are various embodiments for frequency-division multiplexing for wireless power providers using guided surface waveguide probes to transmit power. Guided surface waveguide probes may transmit power on multiple frequencies with potentially overlapping service areas. Frequency-agile wireless power receivers may tune to one or more frequencies. Cost, availability, and/or other information may be provided to the wireless power receivers. Power usage may be reported by the wireless power receivers to power providers.

Wireless-powered cellular networks: key challenges and solution techniques

Abstract: Energy harvesting from ambient sources is emerging as a sustainable and environmentfriendly technique to prolong the lifetime of wireless devices However, harvesting energy from these sources may not be feasible for quality- of-service (QoS)-constrained wireless applications As such, dedicated wireless-powered cellular networks (WPCNs) are currently being investigated to ensure the reliability as well as improved battery lifetime of the wireless devices With emerging WPCNs, a true wireless network can be envisioned, which is free of connectors, cables, and battery access panels, and guarantees freedom of mobility To illustrate and understand the design requirements of WPCNs, this article first points out the key challenges of designing energy-harvesting cellular networks These include the doubly near-far problem, the signal-to-noise ratio (SNR) outage experienced by the energy-harvesting devices located toward the cell-edge, the spatial characterization of the SNR outage zone, the additional resource consumption at energy transmitting sources, and the problems related to designing fairness-constrained user scheduling schemes A brief overview of the related research advancements in WPCNs and a summary of their limitations are then provided Finally, we list a few suggestions and design considerations that can potentially tackle the major challenges in emerging WPCNs and open up new research directions

Cloud-based Wireless Network: Virtualized, Reconfigurable, Smart Wireless Network to Enable 5G Technologies

Abstract: In recent years, information communication and computation technologies are deeply converging, and various wireless access technologies have been successful in deployment. It can be predicted that the upcoming fifth generation mobile communication technology (5G) can no longer be defined by a single business model or a typical technical characteristic. 5G is a multi-service and multi-technology integrated network, meeting the future needs of a wide range of big data and the rapid development of numerous businesses, and enhancing the user experience by providing smart and customized services. In this paper, we propose a cloud-based wireless network architecture with four components, i.e., mobile cloud, cloud-based radio access network (Cloud RAN), reconfigurable network and big data centre, which is capable of providing a virtualized, reconfigurable, smart wireless network.