Maslak ve Şişli lokasyonlarında 4G sinyal gücünün haritalandırılması ve topoğrafya ile ilişkilendirilmesi
Mapping of 4G signal strength in Maslak and Şişli locations and relationship with topography
Yazar: EYÜP KAYA
Danışman: PROF. DR. ŞİNASİ KAYA
İstanbul Teknik Üniversitesi / Bilişim Enstitüsü / İletişim Ana Bilim Dalı / Uydu Haberleşmesi ve Uzaktan Algılama Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Bilim ve Teknoloji = Science and Technology ; Elektrik ve Elektronik Mühendisliği = Electrical and Electronics Engineering ; İletişim Bilimleri = Communication Sciences
Dizin: 4G = Fourth-Generation Wireless Telephone Technology ; Hareketli iletişim = Mobile communication ; Mobil teknoloji = Mobile technology ; Sinyal saptama = Signal fixing ; Topoğrafya = Topography ; İletişim = Communication ; İletişim teknolojisi = Communication technology ; İstanbul-Maslak = İstanbul-Maslak ; İstanbul-Şişli = İstanbul-Şişli

Özet:
Günümüzde hızla gelişme gösteren teknolojilerin en başında mobil ürünlere ait teknolojiler yer almaktadır. Mobil ürünler kategorisinde kuşkusuz en teknolojik ve tüketiciler tarafından en çok tercih edilen ürünler akıllı telefonlardır. Akıllı telefon sektörü sürekli olarak gelişme ve değişim gösteren bir sektördür. Özellikle bu sektördeki gelişmeler kullanıcıların daha hızlı veri indirme/yükleme sunması, uzun batarya ömrü, yüksek çözünürlük ve net görüntü sunan ekranlar, daha kaliteli fotoğraf ve video kaltesi sunan kameralara yöneliktir. Her yeni teknolojinin entegre edilmesiyle akıllı telefonlara yönelik hizmet veren diğer sektörlerinde bu teknolojik gelişmeleri takip etmesi ve bunlara yönelik çalışmalar yapmasını gerektirmektedir. Bu teknolojik gelişmelerden biride baz istasyonları konusundadır. Baz istasyonlarının geliştirilmesi için kapsama alanlarının, verimliliğinin ve kapasitesinin artırılması gibi konular üzerinde çalışılmaktadır.
4G teknolojisinin Türkiye'de ilk olarak Nisan 2016 yılında hizmete sunulmasından daha öncesinde 4G teknolojisini destekleyen akıllı telefonlar kullanıcılara satışa sunulmuştu. Daha sonrasında operatörlerin alt yapılarındaki teknolojik değişiklikler konusunda ilgili yatırımları yapması ve hayata geçirmesi sonrasında kullanıcıların hizmetine sunulmuştur. Bu yatırımlar yeni, teknolojik ve yüksek maliyetli yatırımlar olması sebebiyle ilk olarak yoğun nüfusa sahip şehirlerden başlayarak Türkiye'nin diğer şehirlerine kademeli olarak yayılmıştır. 4G servislerinin büyükşehirlerin büyük bir kısmında kapsama alanları olmasına rağmen henüz küçük şehirlerde ve büyük şehirlerin taşra kısımlarında kapsama alanı genellikle bulunmamaktadır. Bu sebepten ötürü kullanıcılar bu bölgelerde ciddi seviyede 4G servislerinde yararlanamıyorlar veya 3G hızları seviyelerinde hizmete sahip oluyorlar.  
Bu çalışmada veri indirme/yükleme hızı ve performansını direkt olarak etkileyen sinyal gücü seviyesi konusu incelenmiştir.  Sinyal gücü seviyeleri kullanılan akıllı telefonda yer alan işlemci ve modem tümleşik devrelerinin özellikleri dahilinde indirme/yükleme hızlarına ulaşmaktadır. Günümüzde akıllı telefonların büyük bir bölümü altyapı hizmeti sunan operatörlerin sunmuş oldukları hızların çok daha üstü veri indirme/yükleme hızına sahiptirler. Sinyal gücü seviyesinin bağlı olduğu diğer bir önemli hususta operatörler tarafından kurulan baz istasyonlarıdır.  Bu çalışma ile İstanbul şehrinin Maslak, Şişli ve İTÜ Ayazağa kampüsü lokasyonlarında tüm operatörlerin sinyal gücü verilerini toplayarak seviyelerinin incelenmesi, karşılaştırılması, haritalandırılması ve topoğrafya ile ilişkilendirmesi hedeflenmektedir.

Abstract:
Mobile technologies play a major part in today's rapidly improving technologies. 
In mobile devices category, the most technological and preferred devices by costumers are inargubly smartphones. Smartphone sector is a sector which is all the time showing development and change. Especially the developments in this sector is aimed at offering faster downloading or uploading data to customers, longer battery life, high quality of resolution, screens offering 'clear' display, more qualified photograph and video. Because of the fact that every new technology is being entegrated, other areas which give service in terms of smart phones have to follow these technological developments and make researches on these topics. One of these technological developments is about base stations. The development of coverage areas, efficiency and capacity for the development of base stations is being studied.
4G supporting smartphones had been promoted to customers long before 4G technology was introduced for the first time in April, 2016 in Turkey. Afterwards, it was introduced to customers when the operators were done making relevant investments to technological changes in their altyapis and making it real. These investments, due to being new, technological and high costed investments, were grown rapidly to the other cities of Turkey, starting with the cities which have got the highest population. Although the 4G services have coverage in a large part of the metropolitan areas, there is still no coverage in small cities and in rural areas of major cities. For this reason, users are often not able to use 4G services in these areas or have speed and service at 3G levels.
The sources of the signals received by the mobile devices are base stations located in regions determined by the operators. For locations where base stations will be located, operators are taken into consideration some issues. For example; population density in the region by the operator, the number of customers belonging to the operator, the spreading efficiency of the signal from the location or structure to be located, cost, etc. Therefore, the better signal strength usually can be obtained thanks to a large number of base stations at the central points. 
Signal power rate which directly affect the speed of upload or download data and its performance was observed in this research. The signal strength levels on smartphones reach download / upload speeds within the processor and modem features used on that smartphone. In these days, a big majority of smart phones have a far higher speed of download and upload data than the operators that provide infrastructure services. Another important aspect to which the signal strength level depends is the base stations established by the operators. With this study, it aims to gather the signal strength data of all operators at the locations of Maslak, Şişli and ITU Ayazaga campus of the city of Istanbul and to examine, compare, mapping and relationship with topography their levels.
During the data collection, three different routes were determined. Route 1 is Maslak location that the longest one and has a range of 18.7 kilometers. Route 2 which is ITU Ayazağa campus location has a range of 3.9 km and Route 3 which is Şişli location has a range of 7.2 km. Data collection was fulfilled with a different method in Route 3 that is Şişli location. Data were collected on two different days and two different time periods. Data were collected in four different periods as on weekdays Monday and weekend Saturday, in the forenoon and in the afternoon. The reason for choosing these periods is Şişli region. During the weekdays; It has a population of close to 2 million per day due to its central location and transfer points in urban transportation. Considering that this density almost halved at the weekend, it was made in two different periods as weekend and weekdays.
Approximately %78 signal data be found at category of middle and over the middle power signals and rest of %22 signal data stay on category of weak and under the weak power signals which has measured via Turkcell operator along Route 1. Approximately %92 signal data be found at category of middle and over the middle power signals and rest of %8 signal data stay on category of weak and under the weak power signals which has measured via Vodafone operator along Route 1. Approximately %75 signal data be found at category of middle and over the middle power signals and rest of %25 signal data stay on category of weak and under the weak power signals which has measured via Turk Telekom operator along Route 1.
Approximately %100 signal data be found at category of middle and over the middle power signals which has measured via Turkcell operator along Route 2. Approximately %92 signal data be found at category of middle and over the middle power signals and rest of %8 signal data stay on category of weak and under the weak power signals which has measured via Vodafone operator along Route 2. Approximately %78 signal data be found at category of middle and over the middle power signals and rest of %22 signal data stay on category of weak and under the weak power signals which has measured via Turk Telekom operator along Route 2.
Approximately %87 signal data be found at category of middle and over the middle power signals and rest of %13 signal data stay on category of weak and under the weak power signals which has measured via Turkcell operator along first day of Route 3. Approximately %86 signal data be found at category of middle and over the middle power signals and rest of %14 signal data stay on category of weak and under the weak power signals which has measured via Vodafone operator along first day of Route 3.
Approximately %92 signal data be found at category of middle and over the middle power signals and rest of %8 signal data stay on category of weak and under the weak power signals which has measured via Turk Telekom operator along first day of Route 3. Approximately %95 signal data be found at category of middle and over the middle power signals and rest of %5 signal data stay on category of weak and under the weak power signals which has measured via Turkcell operator along second day of Route 3. Approximately %95 signal data be found at category of middle and over the middle power signals and rest of %5 signal data stay on category of weak and under the weak power signals which has measured via Vodafone operator along second day of Route 3. Approximately %93 signal data be found at category of middle and over the middle power signals and rest of %7 signal data stay on category of weak and under the weak power signals which has measured via Turk Telekom operator along second day of Route 3.
When all collected data were examined, it was not observed that there was a clear relationship between height and signal strength. Signal strength was high at some high points, while signal strength was low at some high points. Depending on the location and height of the base stations, the signal strength increases or decreases with respect to the height. In some locations, the signal strength was observed significantly lower. It has been found that these levels for users make it impossible to perform voice communication which is the simplest service or makes it voice communication of very low quality.

In this study, with the data collected, it is aimed to experience the problems of low signal strength experienced by the users and help to find the root cause of these problems. With the collected data, signal strength maps were made up with the location and height information of the regions where signal strength problems were experienced. Moreover, the collected data is intended to assist in possible improvements in locations with low signal strength.