69 research outputs found

    Security-centric analysis and performance investigation of IEEE 802.16 WiMAX

    Get PDF
    fi=vertaisarvioitu|en=peerReviewed

    Radio Communications

    Get PDF
    In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modiïŹed our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the ïŹeld of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

    A Technical and Market study for WiMAX

    Get PDF
    Worldwide Interoperability for Microwave Access (WiMAX) is a broadband wireless technology based on IEEE 802.16-2004 and IEEE 802.16e-2005. This thesis is a study of WiMAX technology and market. The background of WiMAX development is introduced and opportunities and challenges for WiMAX are analyzed in the beginning. Then the thesis focuses on an overview of WiMAX technology, which addresses the physical layer, MAC layer and WiMAX network architecture. The deployment status is investigated in the fourth chapter. Both product development situation and market status are discussed in this section. In the last chapter, the future development trend of WiMAX is addressed

    4G Technology Features and Evolution towards IMT-Advanced

    Get PDF
    Kiinteiden- ja mobiilipalveluiden kysyntĂ€ kasvaa nopeasti ympĂ€ri maailmaa. ÄlykkĂ€iden pÀÀtelaitteiden, kuten iPhone:n ja Nokia N900:n markkinoilletulo yhdistettynĂ€ nĂ€iden korkeaan markkinapenetraatioon ja korkealuokkaiseen kĂ€yttĂ€jĂ€kokemukseen lisÀÀvĂ€t entisestÀÀn palveluiden kysyntÀÀ ja luovat tarpeen jatkuvalle innovoinnille langattomien teknologioiden alalla tavoitteena lisĂ€kapasiteetin ja paremman palvelunlaadun tarjoaminen. Termi 4G (4th Generation) viittaa tuleviin neljĂ€nnen sukupolven mobiileihin langattomiin palveluihin, jotka International Telecommunications Union:in Radiocommunication Sector (ITU-R) on mÀÀritellyt ja nimennyt International Mobile Telecommunications-Advanced (IMT-Advanced). NĂ€mĂ€ ovat jĂ€rjestelmiĂ€, jotka pitĂ€vĂ€t sisĂ€llÀÀn IMT:n ne uudet ominaisuudet, jotka ylittĂ€vĂ€t IMT-2000:n vaatimukset. Long Term Evolution-Advanced (LTE-Advanced) ja IEEE 802.16m ovat IMT-A sertifiointiin lĂ€hetetyt kaksi pÀÀasiallista kandidaattiteknologiaa. TĂ€ssĂ€ diplomityössĂ€ esitellÀÀn kolmannen sukupolven jĂ€rjestelmien kehityspolku LTE:hen ja IEEE 802.16e-2005 asti. LisĂ€ksi työssĂ€ esitetÀÀn LTE-Advanced:n ja IEEE 802.16m:n uudet vaatimukset ja ominaisuudet sekĂ€ vertaillaan nĂ€iden lĂ€hestymistapoja IMT-A vaatimusten tĂ€yttĂ€miseksi. Lopuksi työssĂ€ luodaan katsaus LTE ja IEEE 802.16e-2005 (markkinointinimeltÀÀn Mobile WiMAX) -jĂ€rjestelmien markkinatilanteeseen.The demand for affordable bandwidth in fixed and mobile services is growing rapidly around the world. The emergence of smart devices like the iPhone and Nokia N900, coupled with their high market penetration and superior user experience is behind this increased demand, inevitably driving the need for continued innovations in the wireless data technologies industry to provide more capacity and higher quality of service. The term "4G" meaning the 4th Generation of wireless technology describes mobile wireless services which have been defined by the ITU's Radiocommunication Sector (ITU-R) and titled International Mobile Telecommunications-Advanced (IMT-Advanced). These are mobile systems that include the new capabilities of IMT that go beyond those of IMT-2000. Long Term Evolution-Advanced (LTE-Advanced) and IEEE 802.16m are the two main candidate technologies submitted for IMT-Advanced certification. This thesis reviews the technology roadmap up to and including current 3G systems LTE from the 3rd Generation Partnership Project (3GPP) and IEEE 802.16e-2005 from the Institute of Electrical and Electronics Engineers (IEEE). Furthermore, new requirements and features for LTE-Advanced and IEEE 802.16m as well as a comparative approach towards IMT-Advanced certification are presented. Finally, the thesis concludes with a discussion on the market status and deployment strategies of LTE and IEEE 802.16e-2005, or Mobile WiMAX as it is being marketed

    Design of interface selection protocols for multi-homed wireless networks

    Get PDF
    The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of ‘unreachable zones’, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Connection admission control and packet scheduling for IEEE 802.16 networks

    Get PDF
    Includes bibliographical references.The IEEE 802.16 standard introduced as one of the Wireless Metropolitan Area Networks (WMAN) for Broadband Wireless Access (BWA) which is known as Worldwide Interoperability for Microwave Access (WiMAX), provides a solution of broadband connectivity to areas where wired infrastructure is economically and technically infeasible. Apart from the advantage of having high speeds and low costs, IEEE 802.16 has the capability to simultaneously support various service types with required QoS characteristics. ... While IEEE 802.16 standard defines medium access control (MAC) and physical (PHY) layers specification, admission control and packet scheduling mechanisms which are important elements of QoS provisioning are left to vendors to design and implement for service differentiation and QoS support

    Evaluating WIMAX for real-time vehicular communications

    Get PDF
    Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesOs acidentes rodoviĂĄrios tĂȘm um impacto elevado na sociedade, quer devido Ă s perdas humanas daĂ­ resultantes quer devido aos custos econĂłmicos associados. Este facto tem causado por todo o mundo o estudo de mecanismos que permitam aumentar a segurança rodoviĂĄria. Um exemplo disto Ă© o investimento da Europa em vĂĄrios projectos com vista a desenvolver estes mecanismos, onde a maior parte destas iniciativas consideram a possibilidade dos veĂ­culos comunicarem entre si e/ou com estaçÔes fixas, situadas junto da rodovia. A mobilidade dos veĂ­culos apresenta requisitos especiais, onde as comunicaçÔes sem-fios tĂȘm um papel crucial nestas aplicaçÔes. Contudo, os serviços de segurança rodoviĂĄria requerem alguns requisitos especĂ­ficos, como largura de banda ou em termos de timeliness, que tĂȘm de ser cumpridos independentemente da tecnologia sem-fios usada. Neste trabalho Ă© pretendido avaliar WiMAX para comunicaçÔes relacionadas com a segurança rodoviĂĄria, em que a coexistĂȘncia de diferentes tipos de serviços Ă© uma realidade, onde o uso dos mecanismos de qualidade de serviço fornecidos pelo WiMAX podem ser uma vantagem. ABSTRACT: Road accidents have a huge impact on the society, both because of the resulting human life losses and injuries as well as because of the associ- ated economic costs. This situation fostered the study of mechanisms for increasing road safety all over the world. In Europe, several projects are being funded to develop such mechanisms. Many of the approaches that are being pursued require the ability of the vehicles to communicate with each other and/or with fixed roadside equipments. Due to the mobility con- straints, wireless technologies have a crucial role in this kind of applications. However, road safety services have also specific demands, in terms of band- width and timeliness, that have to be met, independently of the wireless technology used. In this work, it is performed an evaluation of WiMAX for road safety communications, taking into consideration the coexistence of different types of service and that the use of quality of service mechanisms in this wireless technology could be an advantage

    Wireless Technologies for IoT in Smart Cities

    Full text link
    [EN] As cities continue to grow, numerous initiatives for Smart Cities are being conducted. The concept of Smart City encompasses several concepts being governance, economy, management, infrastructure, technology and people. This means that a Smart City can have different communication needs. Wireless technologies such as WiFi, ZigBee, Bluetooth, WiMax, 4G or LTE (Long Term Evolution) have presented themselves as solutions to the communication needs of Smart City initiatives. However, as most of them employ unlicensed bands, interference and coexistence problems are increasing. In this paper, the wireless technologies available nowadays for IoT (Internet of Things) in Smart Cities are presented. Our contribution is a review of wireless technologies, their comparison and the problems that difficult coexistence among them. In order to do so, the characteristics and adequacy of wireless technologies to each domain are considered. The problems derived of over-crowded unlicensed spectrum and coexistence difficulties among each technology are discussed as well. Finally, power consumption concerns are addressed.GarcĂ­a-GarcĂ­a, L.; Jimenez, JM.; Abdullah, MTA.; Lloret, J. (2018). Wireless Technologies for IoT in Smart Cities. Network Protocols and Algorithms. 10(1):23-64. doi:10.5296/npa.v10i1.12798S236410
    • 

    corecore