198 research outputs found

    Performance evaluation of broadband fixed wireless system based on IEEE 802.16

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    Fixed Wireless Access systems operating below 11 GHz have the potential to provide broadband wireless access for non line-of-sight operation. In this paper the performance of a typical broadband fixed wireless system based on the IEEE 802.16-2004 specifications is determined. A scenario for business applications with outdoor customer premises equipment is investigated in the 3.5 GHz frequency band. Different path loss models and terrain types are considered. Coverage and throughput in a sector are determined for this business scenario

    Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment

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    In the last decade, integrated logistics has become an important challenge in the development of wireless communication, identification and sensing technology, due to the growing complexity of logistics processes and the increasing demand for adapting systems to new requirements. The advancement of wireless technology provides a wide range of options for the maritime container terminals. Electronic devices employed in container terminals reduce the manual effort, facilitating timely information flow and enhancing control and quality of service and decision made. In this paper, we examine the technology that can be used to support integration in harbor's logistics. In the literature, most systems have been developed to address specific needs of particular harbors, but a systematic study is missing. The purpose is to provide an overview to the reader about which technology of integrated logistics can be implemented and what remains to be addressed in the future

    Hybrid Strategies for Link Adaptation Exploiting Several Degrees of Freedom in WiMAX Systems

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    Mehanizmi prostiranja radio vala i empirijski modeli za fiksne radijske pristupne sustave

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    This paper provides a survey of the basic mechanisms which influence the propagation of electromagnetic waves at most. It also deals with features of empirical models often used in a process of fixed wireless access network planning and implementation. Four empirical models, SUI, COST 231-Hata, Macro and Ericsson, which are most suitable for path loss prediction for such a system, are presented. By using these propagation models the receiving signal levels are predicted for different types of environment for a WiMAX (Worldwide Interoperability for Microwave Access) system installed in the city Osijek, Croatia. Measurement results of receiving WiMAX power at 3,5 GHz are also presented and compared with the results predicted by using the propagation models.Ovaj rad daje pregled osnovnih mehanizama koji najviÅ”e utječu na prostiranje elektromagnetskih valova. Također se bavi značajkama empirijskih modela koji se često koriste u procesu planiranja i implementacije fiksnih radijskih pristupnih mreža. Predstavljena su četiri empirijska modela koja najbolje odgovaraju za predviđanje gubitaka za ove sustave: SUI, COST 231- Hata, Macro i Ericsson model. KoriÅ”tenjem ovih modela prostiranja napravljena je predikcija razine prijemnog signala za različite tipove okruženja za WiMAX (eng. Worldwide Interoperability for Microwave Access) sustav postavljen u gradu Osijeku, u Hrvatskoj. Predstavljeni su i rezultati mjerenja prijemne snage WiMAX sustava na 3,5 GHz te su uspoređeni s rezultatima predviđenim uporabom modela prostiranja

    WiMax - a critical view of the technology and its economics

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    University of the Witwatersrand Faculty of Engineering and the Built Environment School of Information and Electrical EngineeringMobile Broadband is now more of a necessity than a luxury, especially amongst the younger generation, irrespective of where they live. Mobile WiMax and LTE, the latest and fastest Mobile Broadband technologies, mark significant improvements over 3G networks because they use IP (Internet Protocol) end-to-end. To end-users, this means faster network speeds, better quality services, and increased coverage area. To the Network Operators, this means simplified network architectures, efficient use of resources, and improved security. In this report, the different issues and challenges related to deploying Mobile WiMax (802.16e or 802.16m) in rural South Africa, were identifed and explored. In this project, Atoll, SONAR, and Touch Point analysis tools were used to determine which Mobile Broadband technology is economically and technically suited for rural South Africa. It was found that LTE yields superior performance results than WiMax, which in turn yields superior performance results to all other existing 3G technologies. However it will take time for LTE to reach rural areas therefore WiMax can be considered as a solution to extend Broadband services to rural South Africa and thus assist in bridging the digital divide. Recommendations on how best to deploy Mobile WiMax are made based on observations made from the experimental work.MT201

    WEIRD ā€“ Real Use Cases and Applications for the WiMAX Technology

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    IEEE 802.16/WiMAX is one of the most promising technologies for Broadband Wireless Access, both for fixed and mobile use. This paper presents the structure of some testbeds, set up in the framework of the European project WEIRD, about novel applications running on top of a WiMAX-based end-to-end architecture. The presented testbeds are based on real use case scenarios, including monitoring of impervious areas, tele-medicine and tele-hospitalization

    Aeronautical Data Networks

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    Evaluation Of Multicarrier Air Interfaces In The Presence Of Interference For L-Band And C-Band Air-Ground Communications

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    The use of aeronautical vehicles and systems is continuously growing, and this means current aeronautical communication systems, particularly those operating in the very high frequency (VHF) aviation band, will suffer from severe congestion in some regions of the world. For example, it is estimated that air-to-ground (AG) communication traffic density will at least double by 2035 over that in 2012, based on the most-likely growth scenario for Europe. This traffic growth (worldwide) has led civil aviation authorities such as the FAA in the USA, and EuroControl in Europe, to jointly explore development of future communication infrastructures (FCI). According to international aviation systems policies, both current and future AG communication systems will be deployed in L-band (960-1164 MHz), and possibly in C-band (5030-5091 GHz) because of the favorable AG radio propagation characteristics in these bands. During the same time period as the FCI studies, the use of multicarrier communication technologies has become very mature for terrestrial communication systems, but for AG systems it is still being studied and tested. Aiming toward future demands, EuroControl and FAA sponsored work to define several new candidate AG radio systems with high data rate and high reliability. Dominant among these is now an L-Band Digital Aeronautical Communication Systems (L-DACS): L-DACS1. L-DACS1 is a multicarrier communication system based on the popular orthogonal frequency division multiplexing (OFDM) modulation technique. For airport surface area communication systems used in C-band, EuroControl and FAA also proposed another OFDM communication system based on the IEEE 802.16e standard, termed aeronautical mobile airport communication system (AeroMACS). This system has been proposed to provide the growing need of communication traffic in airport environments. In this dissertation, first we review existing and proposed aviation communication systems in VHF-band, L-band and C-band. We then focus our study on the use of multicarrier techniques in these aviation bands. We compare the popular and dominant multicarrier technique OFDM (which is used in cellular networks such long-term evolution (LTE) and wireless local area networks such as Wi-Fi) with the filterbank multicarrier (FBMC) technique. As far as we are aware, we are the first to propose and evaluate FBMC for aviation communication systems. We show, using analysis and computer simulations, along with measurement based (NASA) air-ground and airport surface channel models, that FBMC offers advantages in performance over the OFDM schemes. Via use of sharp filters in the frequency domain, FBMC reduces out of band interference. Specifically, it is more robust to high-power distance measurement equipment (DME) interference, and via replacement of guard bands with data-bearing subcarriers, FBMC can offer higher throughput than the contending L-DACS1 scheme, by up to 23%. Similar advantages over AeroMACS pertain in the airport surface channel. Our FBMC bit error ratio performance is comparable to that of the OFDM schemes, and is even better for our ā€œspectrally-shapedā€ version of FBMC. For these improvements, FBMC requires a modest complexity increase. Our final contribution in this dissertation is the presentation of spectrally shaped FBMC (SS-FBMC). This idea allocates unequal power to subcarriers to contend with non-white noise or non-white interference. Our adaptive algorithm selects a minimum number of guard subcarriers and then allocates power accordingly to remaining subcarriers based on a ā€œwater-filling-likeā€ approach. We are the first to propose such a cognitive radio technique with FBMC for aviation applications. Results show that SSFBMC improves over FBMC in both performance and throughput
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