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Wireless Communications (wireless + communication)

Distribution by Scientific Domains
Engineering86%

Terms modified by Wireless Communications

  • wireless communication system
    		•

    Selected Abstracts

    Layered view of QoS issues in IP-based mobile wireless networks

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2006
    Haowei Bai
    Abstract With the convergence of wireless communication and IP-based networking technologies, future IP-based wireless networks are expected to support real-time multimedia. IP services over wireless networks (e.g. wireless access to Internet) enhance the mobility and flexibility of traditional IP network users. Wireless networks extend the current IP service infrastructure to a mix of transmission media, bandwidth, costs, coverage, and service agreements, requiring enhancements to the IP protocol layers in wireless networks. Furthermore, QoS provisioning is required at various layers of the IP protocol stack to guarantee different types of service requests, giving rise to issues related to cross-layer design methodology. This paper reviews issues and prevailing solutions to performance enhancements and QoS provisioning for IP services over mobile wireless networks from a layered view. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Design and implementation of WAP-based LAN segment management system using RMON MIB

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2003
    Jong-Keun Kim
    Advances in LAN technology have enabled fast data transmission. However, without effective management of these resources, congestion of networks as well as waste of resources are inevitable. Therefore, it is necessary to supervise, report, and even control, if necessary, the network resource status so that the communication network can be effectively operated without service interruption by monitoring traffic among the hosts. Web-based network management systems have been developed and applied for remote management without using specific applications. However, such web-based network management systems have limited manager mobility and poor performance. To overcome such disadvantages, this paper proposes a network management system using wireless communication. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    EM design of broadband RF multiport toggle switches

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2004
    W. Simon
    Abstract Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329,337, 2004. [source]

    Ultra-wideband coplanar boat microstrip patch with modified ground plane by using electromagnetic band-gap structure for wireless communication

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Dalia N. Elsheakh
    Abstract A new antenna structure using triangular patch alongside a small trapezoidal shape ground plane with proximity fed is proposed in this article. The proposed antenna design provides a bandwidth in the range from 2 < 35 GHz with band discontinuities. Improvement is done in antenna performance by using electromagnetic band-gap (EBG) structure. First, dumb-bell shapes as 2D-EBG are etched in the feeding line. Second, embedded spiral artificial magnetic conductor with four arms to introduce sufficient inductive impedance is done. The resultant bandwidth increases to three times than the original bandwidth and reduces the antenna size as well as enhancing the antenna gain. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1159,1164, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25129 [source]

    60 GHz SoC/SoP radio system for high data-rate transmission

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2010
    K. C. Eun
    Abstract We present the 60 GHz CMOS and system-on-package (SoP) research activities in Korea Advanced Institute of Science and Technology for high data-rate and short-range wireless communication. A low-power single-chip resonant frequency CMOS receiver for 60 GHz mobile terminals consists of four-stage current reuse LNA, resistive mixer, Ka-band low-phase noise VCO, high-suppression frequency doubler, and two-stage current reuse drive amplifiers. The receiver conversion gain and input P1dB are ,9.5 dB and ,12.5 dBm, respectively, with a size of 2.67 × 0.75 mm2 and power consumption of 21.9 mW. The integration and communication tests of a transmitter/receiver (Tx/Rx) radio have been demonstrated at a data rate of 3 Gbps for short-range transmission and with a communication distance of over 3.5 m at 650 Mbps data rate. The design and fabrication of mmW subcircuits, such as low-loss transmission lines and transitions with noble air cavity structures, a high-Q resonator using zigzagged dual-row via posts and a ,/4 short stub, and the monolithic integration of band-pass filter and antennas, have been performed for low-temperature cofired ceramic SoP integration with a size of 37 × 11 mm2 for the whole Tx or Rx radio. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 667,673, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25024 [source]

    Dual-band monopole antenna excited by a capacitive coupling feed for WLAN applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2007
    Chih-Yu Huang
    Abstract A printed dual-band T-shaped monopole antenna with a shorted strip fed by a coupling microstrip line for wireless communication in the wireless local-area network (WLAN) band is studied. The proposed antenna can provide two separate impedance bandwidths of 101 MHz (about 4.1% centered at 2.45 GHz) and 1490 MHz (about 27% centered at 5.5 GHz), making it easier to cover the required bandwidths for WLAN operation in the 2.45 GHz band (about 3.4% bandwidth required) and 5.2/5.8 GHz bands (about 13% bandwidth required). We can easily find the enhancement of impedance bandwidth by using capacitive coupling feed. Details of the proposed antenna design and experimental results are presented and discussed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1135,1138, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22380 [source]

    Simulation of Accuracy Performance for Wireless Sensor-Based Construction Asset Tracking

    COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2009
    Miros, aw J. Skibniewski
    In particular, identifying the location of distributed mobile entities throughout wireless communications becomes the primary task to realize the remote tracking and monitoring of the construction assets. Even though several alternative solutions have been introduced by utilizing recent technologies, such as radio frequency identification (RFID) and the global positioning system (GPS), they could not provide a solid direction to accurate and scalable tracking frameworks in large-scale construction domains due to limited capability and inflexible networking architectures. This article introduces a new tracking architecture using wireless sensor modules and shows an accuracy performance using a numerical simulation approach based on the time-of-flight method. By combining radio frequency (RF) and ultrasound (US) signals, the simulation results showed an enhanced accuracy performance over the utilization of an RF signal only. The proposed approach can provide potential guidelines for further exploration of hardware/software design and for experimental analysis to implement the framework of tracking construction assets. [source]

    New centralized automatic vehicle location communications software system under GIS environment

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2005
    Omar Al-Bayari
    Abstract Recent advances in wireless communications and networks have integrated relatively new technologies such as Global Positioning System (GPS), to the popular Global System for Mobile Communication (GSM), second generation cellular systems and the Geographic Information Systems (GIS) technologies. Automatic Vehicle Location (AVL) is based on a combination of GPS, GIS and telecommunication technologies. Automatic Vehicle Tracking systems are more and more used for different purposes, especially those related to tracking one vehicle or a fleet of vehicles. In this work, we introduce a new AVL system, which is based and developed under GIS software environment. The centralized software at the control station offers a new technology of transferring the intelligence of tracking system from the car unit, into the control office PC software. Centralized software will reduce the programming efforts in the car unit and will offer better fleet management. Moreover, the core of our system is based on the objects or the controllers of the GIS software, which reduces dramatically the overall system cost. Our system provides an easy access to change the functions of the system, with great possibility to satisfy the local needs. The design of our software will be presented with an explanation of the new supporting technologies that were to create the system. Finally, our software system has been validated using data from local road networks. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Experimental studies of direction of arrivals using a smart antenna testbed in wireless communication systems

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2003
    Shiann-Shiun Jeng
    Abstract This paper presents some preliminary results from experimental studies on space-division-multiple-access (SDMA) for wireless communications. A smart antenna system utilizing direction-of-arrival (DOA)-based beamforming techniques can enhance signal quality by reducing co-channel interference from mobiles located at angles spatially distinct from the base station. Adopting both smart uplink and downlink beamforming, a communication system with an antenna array can increase the cell coverage of a base station and significantly boost capacity compared with conventional antenna systems. However, successful implementation of DOA-based beamforming techniques depends on the DOA characteristics. This paper presented the feasibility of direction finding and DOA variation with respect to frequency. Furthermore, the angle spread was studied for selected environments. The results demonstrate the feasibility of applying proposed smart antenna system utilizing DOA-based beamforming algorithm for increasing channel capacity and improving system performance in frequency-division-duplex (FDD) wireless communication systems. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    High-power RF photodiodes and their applications

    LASER & PHOTONICS REVIEWS, Issue 1-2 2009
    T. Nagatsuma
    Abstract There has been an increasing interest in photonic generation of RF signals in the millimeter-wave (30 GHz,300 GHz) and/or terahertz-wave (0.1 THz,10 THz) regions, and photodiodes play a key role in it. This paper reviews recent progress in the high-power RF photodiodes such as Uni-Traveling-Carrier-Photodiodes (UTC-PDs), which operate at these frequencies. Several approaches to increasing both the bandwidth and output power of photodiodes are discussed, and promising applications to broadband wireless communications and spectroscopic sensing are described. [source]

    Planar ultrawideband antenna array for short-range wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Osama M. H. Ahmed
    Abstract In this article, novel 2-element and 4-element planar ultrawideband (UWB) antenna arrays with bidirectional radiation patterns based on identical UWB antenna elements for UWB communications applications have been proposed, simulated and experimentally investigated. Each array is constructed by means of feeding omni-directional printed UWB monopole antennas with a UWB power divider. The proposed 2-element antenna array yields an impedance bandwidth of 110% (3.1,10.6 GHz) covering the whole UWB frequency bandwidth while the impedance bandwidth is multi-band in case of the 4-element antenna array because of the increasing effect of mutual coupling among antenna elements. The calculated gain of the 2-element and 4-element array is quite stable with about 3 and 6 dB higher than that of the single element, respectively. Both measured and calculated E-plane radiation patterns of the array and the single element are almost the same while the H-plane radiation patterns of the array are distinctively bidirectional compared to the omni-directional pattern of the single element. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1061,1066, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25140 [source]

    Planar slot antenna with PBG filter for wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2007
    Fabrizio Consoli
    Abstract A planar circular slot antenna, integrated with a band-stop photonic bandgap filter is presented here. The complete realized prototype is suitable to cover the bandwidth requirements of many wireless communication standards in one solution. The work describes the detailed study of both the antenna and the PBG filter properties. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 551,555, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22191 [source]

    A compact, broadband antenna for planetary surface-to-surface wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2006
    Philip Barr
    Abstract The compact microstrip monopole antenna (CMMA) is a novel antenna design that combines a microstrip patch antenna with a 3D structure to attain a highly directive, broadband, compact antenna. A tri-lobed patch (TLP) is designed to minimize the patch's area while reducing the antenna's operating frequency. A grounding wall (GW) connects the patch to the ground plane and a vertical-enclosure wall (VEW) extends up, away from portions of the patch's perimeter. This VEW supplies the antenna with a higher directivity in the radial direction and also reduces the operating frequency. The CMMA was designed to operate at 2.23 GHz, but experimental results have shown this antenna resonates at 2.05 GHz which is on the order of approximately ,0/11.6 with respect to the antenna's largest dimension, with a directivity and bandwidth of 6.0 dBi and 130 MHz (6.3%), respectively. This miniature, radially emitting antenna makes the CMMA attractive for planetary-based surface-to-surface communications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 521,524, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21397 [source]

    A reconfigurable Yagi antenna for wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2003
    P. F. Wahid
    Abstract The design of a reconfigurable Yagi antenna that can operate at two frequencies, 2.4 GHz and 5.78 GHz, for use in wireless communications is presented. The Yagi can be reconfigured through the use of appropriate switches placed on the elements of the antenna. This paper shows the feasibility of this antenna and presents simulated and measured results at the two frequencies. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 140,141, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10997 [source]