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Sakhno Oksana VladimirovnaFaculty: Computer Information Technologies and AutomationDepartments: Automation and Telecommunication (AT)Speciality: Telecommunication Systems and NetsThe theme of master's work:“Optimization of transfer of management by a call in networks of the third generation”The supervisor of studies: Turupalov Victor Vladimirovich |
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Abstract |
Abstract to master’s work
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ContentsActualityTarget settingGraphic presentationFeasible solutionsChannels of information
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Actuality3G – wireless technology of global communications that enables transfer of digital voice, data and video. In spite of the fact that mobile communications are still used to a greater extent for voice transfer possibility to transfer different kinds of data is interesting to commercial use. Operators, for example, could propose service payment using mobile phone or remote access to the enterprise network. There are many interpretations of the meaning of 3G, but universal determination is the determination that gives ITU (International Telecommunication Union). ITU works with industry organizations all over the world, defines and ratifies technical requirements, standards and rules of using of the spectrum for 3G-nets in the context of IMT-2000 (International Mobile Telecommunications-2000). IMT-2000 are the recommendations that apply to the using of frequency spectrum and technical peculiarity for whole family of standards 3G. Family of standards 3G includes wide spectrum of wireless technologies like CDMA (Code Division Multiple Access) 2000, UMTS (Universal Mobile Telecommunications Service) and WCDMA (Wide-CDMA). In according with IMT-2000 recommendations 3G-nets should provide: -high transfer data rate indoor and outside; -symmetrical and asymmetrical data transfer; -to keep up Internet Protocol (IP) è Real Time Video; -high quality of voice; -more compactness of spectrum and efficiency of its using; -possibility of global roaming. IMT-2000 program is based on number of signs that define the principles of construction 3G-system. From the first step of deployment 3G-nets should provide: -about 2,048 Mbitps at low mobility (speed less than 3 km/h) and local zone of coverage; -about 144 kbitps at high mobility (about 120 km/h) and wide zone of coverage; -about 64 (144) kbitps at global coverage (satellite communication). Target setting3G-nets use whole frequency band in every cell. It means that they are dynamic nets with variable zone of coverage. 3G-operators should be prepared for some specific hardships of transmission. One of the hardest problems of network’s optimization is control of radiofrequency interference. Attentive frequency planning provides high quality transfer, but it not rules out the local tuning. Design and exploitation features of 3G-nets: base stations have relatively low power level, big enough percent of subscribers being found in regime of permanent switching between two and more cells. This happens when subscriber move from coverage zone of one cell to coverage zone of another cell or because of problems with the quality. For this switching is used a special procedure that called transfer of management by a call – handover. The handover could be realized between base stations of one operator, between base station and local wireless network IEEE 802.11 standard, between base stations of different mobile operators (roaming). Optimization of handover consist in decrease of needless overlapping between coverage zone of base station, in elaboration number of procedures that provide co-ordination of 3G-nets with IEEE 802.11 networks. Graphic presentation
Figure 1.1 – Graphic interpretation of “softhandover” (7 frames, infinite loop)
“Softhandover” – fluent transfer of management by a call between âûçîâîì ìåæäó base stations. This technology imply, that mobile station have a chance to have two channels (new and old) in the moment of switching and some seconds later. Feasible solutionsDecrease of needless overlapping between coverage zones of adjacent base station could be made with regulation of coverage depending on cell’s loading. Decrease of overlapping lessens interference from neighbors base stations and exclude chronic overload of the network. The coverage of base station could be changed by regulation of central petal of antenna diagram. Operator should find compromise between necessity of big enough softhandover zone providing and requisite coefficient of network capacity using. Because when handover zone decrease, quality parameter is decreasing too. This kind of coverage could be made by principle new antenna with distance tilt control that keep out optimal power level. Using this type of antennas could provide more clear-cut border of coverage zone and decrease negative effects of mutual influence adjacent cells. Successful integration of networks 802.11/3G could be achieved by using project solutions like new net node – hub IOTA (Integration Of Two Access Technologies – 3G and 802.11) and program resources that provide access to general services 802.11/3G on client’s terminals. There are two classes of services end-consumers: tightly coupled co-ordination and loosely coupled co-ordination. Channels of information1. http://www.mobilecomm.ru/view.php?id=184 2. http://www.pbxlib.com.ua/mobile/article_130.html 3. http://www.pbxlib.com.ua/mobile/article_126.html 4. http://www.3gnews.ru/articles/679/ 6. http://www.nestor.minsk.by/sr/2003/06/30601.html 7. http://mobilnik.ua/articles/152.html 8. http://www.mport.ru/articles/phone/technology/tech_from_mport5/ 10. http://www.cnews.ru/topics/body/index.shtml?2007/02/16/236212 11. http://www.glazok.ru/news/mobile/2006/01/25/10859/ 12. http://www.3gnews.ru/articles/1659/
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