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Cep telefonları ve cep telefonu antenleri

Başlık çevirisi mevcut değil.

  1. Tez No: 66857
  2. Yazar: ÖNDER TÜRKOĞLU
  3. Danışmanlar: DOÇ. DR. CEVDET IŞIK
  4. Tez Türü: Yüksek Lisans
  5. Konular: Elektrik ve Elektronik Mühendisliği, Electrical and Electronics Engineering
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 1997
  8. Dil: Türkçe
  9. Üniversite: İstanbul Teknik Üniversitesi
  10. Enstitü: Fen Bilimleri Enstitüsü
  11. Ana Bilim Dalı: Elektronik ve Haberleşme Mühendisliği Ana Bilim Dalı
  12. Bilim Dalı: Devreler ve Sistemler Bilim Dalı
  13. Sayfa Sayısı: 189

Özet

ÖZET Günümüzde gelişen teknoloji ve toplumsal yapı sebebiyle insanların ihtiyaçları da değişti. Metropolitanlarda yaşayan vatandaşların yeni hayat tarzları ise hareketlilik üzerine kuruludur. Bu, bir vatandaş nerede olursa olsun, haberleşmesinin bir ihtiyaç olduğu mantığını daha da belirginleştirir. Kamu telefon ağları gerek aboneler arası gerek şehirler arası gerekse milletler arası telefon görüşmelerine olanak sağlamakla beraber hareket kabiliyeti olmadığı için, haberleşmede radyo tipi teknikler araştırıldı ve geliştirildi. Fiziki dünyanın da etkisiyle mobil haberleşmede bir çok kısıtlamalar ortaya çıktı. Mobil terminaller genellikle, küçük, hafif, az hacimli ve yatay düzlemde yön süz bir ışıma diyagramına sahip olmayı gerektirir. Uygulamada antenler propagasyon karakteristiklerini kuşatmalı ve hareket halindeyken oluşan mekaniksel ve çevresel zararlara karşı sağlam olmalıdır. Cep telefonlarına monte edilen antenlerin bazı karakteristik özellikleri vardır. Cep telefonu kullanılırken yönü rastsal değiştiği için antenin kutuplama yönü ve ışıma diyagramı sabit olamaz. Işıma diyagramı ve ışıma verimliliği insan vücuduna yakınlaşınca değişir. Bu nedenle cep telefonu anteninin dikey kutuplama ve yönsüz ışıma diyagramına sahip olması çok zordur. Cep telefonu anten tasarımında, efektif kazancı optimumlaştırmaya çalışmak önemlidir Bir anten tasarlanırken; çoklu yol propagasyon çevresinde efektif kazancı, cihazın, konuşurken, taşınırken ve arama durumlarındaki efektif kazancı belirlenmelidir. Bu çalışmada 1. Bölümde mobil haberleşmenin temelleri, 2. Bölümde hücresel haberleşme felsefesi, S. Bölümde GSM, 4. Bölümde propogasyon, 5. Bölümde anten tasarımı 6-7. Bölümde cep telefonlarında kullanılan antenler, 8. Bölümde anten analizi, ve 9. Bölümde değerlendirme incelenmiştir. xııı

Özet (Çeviri)

SUMMARY Human requirements was changed by the transformation of development of the thecnology and the social structure. In generally, world is changed into big villages such as metropolitans. New life style of the citizens live in metropolitans bases on mobility. Wherever any citizen is in there, the requirement of communication is important. Public telephone networks enable to calling between subscribers and calling city to city and internationally. However, since they have no mobility, new technics such as radio types was researched and developed in communication. The telephone was connected to each other to call from wires by using communication channels, by local exchange. A lot of boundary was seen in mobile communication because of the physical world. Generally, requirement of the mobile terminal is small, light, low profiled and omni-directional radiation pattern in horizontal plane. In application, The Antennas must have propagation characteristics and must be strong against to mechanical and envoiremental damages while movement. The antenna mounted on portable telephone has some characteristic property. First, polarization direction and radiation pattern of antenna cannot be fixed since direction of phone varies randomly while calling. Second, radiation pattern and ra diation efficiency is varied when the antenna is closed to human body. Because of these reasons, realization of vertical polarization of the portable phones is difficult In the design of antenna of the portable radio, optimization of effective gain is important Theoretical analyzes must consist radiation pattern variation depends on coverage effects of the portable radio, induction of radiation efficiency of antenna xivdepends on closeness effects to human body and variation of polarization and pattern depends on operation with human. In the design of any antenna; 1) Effective gain in the multipath envoirement 2) effective gain of portable phone while moving, calling and speeching must be obtained. Since effect of the human body isn't seen, not only truth of evaluation depends on free space radiation pattern isn't enough for calculating of an antenna practical performance, but also effect of RF power radiated from the antenna on the human body is necessary. In this paper, 1. Chapter; fundamental of mobile communication, 2. Chapter; principles of cellular radio, 3. Chapter; GSM, 4. Chapter; propagation, 5. Chapter, antenna design, 6. Chapter; first order or basic mobile hand-set antennas, 7. Chapter; advanced mobile hand-set antennas, 8. Chapter; mobile antenna analyzes (by FDTD method) 9. Chapter; Probability Theory is discussed. XVThe importance of GSM system is increasing in this era of communications. Cellular systems now give more freedom to people who want to talk or simply communicate without preventing them moving as long as they are within the coverage area of the network. Digital technology is the keyword behind all these advantages of mobile communications. Cellular telecommunications is one of the fastest growing and most demanding telecomminications applications ever. Today it represents a large and continuously increasing percentage of all new telephone subscriptions around the world. In many cases, cellular solutions successfully compete with traditional wire networks and cordless telephones. In the long term perspective cellular systems, using a digital technology, will become the universal method of telecommunication. In 1982 the Nordic PTTs sent a proposal to CEPT (Conference Europeenne de Posal et Telecommunications) to specify a common European telecommunication service at 900 MHz. A standardisation group for GSM-Global System for Mobile communication-was established in order to formulate the specifications for this pan-European mobile cellular radio system. During 1982-1985 there were discussions of whether to build an anologue or a digital system but in 1985 it was decided to specify a digital system. The next step was to choose between a narrowband and a broadband solution. In 1986 there was a field test in Paris where different companies, with different solutions, competed. In May 1987 the narrowband TDMA (Time Division Multiple Access) solution was chosen. At the same time, the first 13 countries (in United Kingdom two operators) signed MoU (Memorandum of Understanding) commiting themselves to fulfill the specifications and promised to have a GSM system running by July 1, 1991, thus opening a very large potential market. In addition to international roaming, GSM provides new user services, such as high speed data communication, facsimile and short message service. The GSM technical specifications are designed to work together with other standards, e.g. ISDN (Integrated Services Digital Network). Interworking between the standards is in this way assured. The system specifications for the GSM network are: Frequency band: Uplink: 890 MHz-915 MHz xvi- stolen individual equipments. The network operator can choose to allow, or bar use, or simply record the use of such an item of equipment. An Authentication Centre (AUC) is used to provide the keys for security of subscriber identity and encrypting of information across both the network and radio air interfaces. It also provides safeguards againts fraud for the network operator and the subscriber. The equpment described above provides the ability to route calls, but to operate it as a telecommunications network requires further layers of manegement control. These layers are jointly described as a Telecommunications-Management Network (TMN). The lower of these two - the Operations and Maintenance Centre (OMS), provides the machanism to define the operating configurations of individual nodes (Msc, BSC, BTS and databases) and the equipment within them, and monitor their performance. It allows equipment to be brought in and out of service and handles fault reports. OMC staff typically arrange fault and routine maintenance activities. XIX- stolen individual equipments. The network operator can choose to allow, or bar use, or simply record the use of such an item of equipment. An Authentication Centre (AUC) is used to provide the keys for security of subscriber identity and encrypting of information across both the network and radio air interfaces. It also provides safeguards againts fraud for the network operator and the subscriber. The equpment described above provides the ability to route calls, but to operate it as a telecommunications network requires further layers of manegement control. These layers are jointly described as a Telecommunications-Management Network (TMN). The lower of these two - the Operations and Maintenance Centre (OMS), provides the machanism to define the operating configurations of individual nodes (Msc, BSC, BTS and databases) and the equipment within them, and monitor their performance. It allows equipment to be brought in and out of service and handles fault reports. OMC staff typically arrange fault and routine maintenance activities. XIXDownlink: 935 MHz-960 MHz Carrier distance: 45 MHz Carrier separation: 200 kHz (the first carrier at 890.2 MHz) Modulation: GMSK (Gaussian Minimum Shift Keying) Air transmission rate: 270 kbit/ s Access method: TDMA (Time Division Multiple Access) In cellular mobile communication systems, communication occurs between the exchange and roaming mobile stations. The geographical area in which the mentioned communication occurs, is called a“cell”. And the Location Area is the name given to a certain area where all these certain group of cells come together. Each cell has a Base Transceiver Station (BTS) operating on a set of radio channels. These are different from the channels used in neighbouring cells to avoid interference. A group of BTSs is controlled by a Base Station Controller (BSC). Each area in the system has a certain identity-Location Area Identity and the system uses this to find the active subscriber. A number of Location Areas is named as an MSC Service Area. Additionally, the system needs certain databases to keep track of subscriber, which the most important of these databases is the Home Location Register (HLR). The Visitor Location Register (VLR) also is another database containing information about all the MSs currently located in the MSC area. AUC, whose function is to provide the HLR with authentication parameters is connected to the HLR. SIM (Subscriber Identity Module) is a small unit containing the subscription and together make up the mobile station with the mobile equipment. If someone in the fixed network (PSTN) wants to make a call to a GSM subscriber, the exchange in the PSTN will connect the call to a gateway, which is often realized in an MSC. The Mobile Station (MS) is the subscriber equipment. It may be in the form of a permanently installed vehicle mobile, a transportable which operates as a full vehicle mobile, which may also be undipped and used independently, or a portable capable of being carried in a pocket or briefcase. Portable may also be fitted to vehicle mounted adaptors. The MS is thus available in various forms to suit the user, and will provide him/ her with voice and/ or data facilities. The Base Transceiver Station (BTS) provides the radio path equipment between the MS and the fixed network. It contains radio transmitters and receivers together with channel coding functions to maintain the integrity of the transmitted data. Speech and control information are both carried in digital form in GSM. xvu

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