This master thesis investigates the possibility of locating LTE base stations, known as eNodeBs, using signal measurements collected by routers on trains. Four existing algorithms for transmitter localization are adopted: the centroid, strongest signal, Monte Carlo path loss simulation and power difference of arrival (PDoA) methods. An improved version of Monte Carlo path loss simulation called logloss fitting is proposed. Furthermore, a novel localization method called sector fitting is presented, which operates solely on the cell identity and geographical distribution of the measurements. The methods are evaluated for a set of manually located eNodeBs, and the results are compared to other external systems that can be used to locate eNodeBs. It is found that the novel sector fitting algorithm is able to considerably improve the accuracy of the logloss fitting and PDoA methods, but weighted centroid is overall the most accurate of the considered methods, providing a median error of approximately 1 km. The Google Geolocation API and Mozilla Location Service still provides estimates that are generally closer to the true location than any of the considered methods. However, for a subset of eNodeBs where measurements from all sectors are available, the novel sector fitting algorithm combined with logloss fitting outperforms the external systems. Therefore, a hybrid approach is suggested, where sector fitting combined with logloss fitting or weighted centroid is used to locate eNodeBs that have measurements from all sectors, while Google Geolocation API or Mozilla Location Service is used to locate the remaining eNodeBs. It is concluded that while the localization performance for those eNodeBs that have measurements from all sectors is relatively good, further improvements to the overall results can likely be obtained in future work by considering environmental factors, the angular losses introduced by directional antennas, and the effects of downlink power control.

This diploma thesis deals with the study and measurement of coexistence scenarios that can occur between the LTE and LoRa systems in the unlicensed ISM band 2.4 GHz. A common radio frequency band in which LTE and LoRa systems can coexist is defined. An appropriate laboratory measurement is proposed and realized, allowing automatized measurement of the defined coexistence scenarios. For this purpose, a personal computer, professional measurement equipment and software MATLAB are utilized. Functionality of the proposed concept is verified by extensive measurements. The obtained results are graphically shown and discussed in detail.

Cíl disertační práce leží v oblasti modelování a vyhodnocení bezdrátových komunikačních systémů s dvojrozměrným rozprostíráním signálu a jejich klíčových parametrů v závislosti na vybraných vlastnostech moderního bezdrátového komunikačního řetězce. Výzkumné metody použité v této práci spočívají především ve vývoji softwarového simulátoru pro prostředí Matlab, s jehož pomocí, a s využitím statistického přístupu, jsou navržené algoritmy ověřeny. Dále je použit simulátor fyzické vrstvy dle 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), vyvinutý na Technické univerzitě ve Vídni. Tento představuje ideální platformu pro implementaci metody dvojrozměrného (2D) rozprostírání a její vyhodnocení s přihlédnutím k současným bezdrátovým komunikačním systémům. Zjištění prezentovaná v této práci představují především ověření účinnosti systému nazvaného jako Variable Spreading Factor - Orthogonal Code Frequency Division Multiplex (VSF-OFCDM), který využívá principu 2D rozprostírání signálu a zjištění, že VSF-OFCDM systém překonává systémy využívající Orthogonal Division Frequency Multiplex (OFDM), nebo Code Division Multiple Access (CDMA). Dále byla navržena metoda 2D rozprostírání signálu v systému LTE, kde se též potvrdila její účinnost. Díky účinnějšímu potlačení vlivu rychlé variace přenosového kanálu v závislosti na frekvenci a čase, dosahuje systém VSF-OFCDM znatelně vyšší datové prostupnosti.

Key tasks of this work are to create the simulation of a wireless network in ns-3 and to stream a video over this network by using MPEG-DASH technology. It describes the tools and methods how to encode a video according to MPEG-DASH. It is explained what is needed to run video server, which uses MPEG-DASH technology to stream videos. Then, it is described how a simulation of wired and wireless WiFi and LTE networks is created. The simulation starts a server and shows how it works, how many nodes can be used and chooses suitable segment duration.

Master‘s thesis discusses about the issues of LTE-Advanced networks. The paper is divided into 4 parts. At the beginning describes some differences which are other then are mentioned in previous 2G and 3G networks. Next chapter focuses on the physical layer LTE. It describes the structure of transmission frames, channels and functions of transmission signals. It also describes briefly the function of HARQ process, turbo encoder and rate matcher. The penultimate chapter focuses on the design of the LTE-Advanced duplex simulator. The last chapter summarizes the results of the created round-trip simulator in the Matlab environment.

Diploma thesis is focused on an analysis of radio conditions of indoor LTE-A mobile networks. Measurements of the Huawei LTE-A radio access network were performed using the R&S TSMW spectral analyser. Results have been processed and discussed. The practical part of diploma thesis also consists of a development of a program for processing the data sets obtained from R&S TSMW spectral analyzer.

The master thesis is focused on control procedures in EPS-IMS networks. Firstly the thesis describes systems IMS and EPS. The second part of thesis includes the theory of control procedures in EPS such as cell acquisition, random access procedure, identification of subscriber, authentication of subscriber, security procedures, tracking area procedure, default bearer creation, implementation of CSFB procedure and detach procedure. Processes related to subsystem IMS such as registration to IMS, bearer creation for IMS signalling and voice service VoLTE are the next part of thesis. The next main topic is the VoLTE implementation problematic and VoLTE cooperation with diverse terminals. There is also explained the principle of Circuit Switched Fallback for realization voice services in EPS without VoLTE service. All procedures mentioned above except of procedures which are related to IMS were captured and analyzed using software Wireshark and QualiPoc. The final part of the thesis is lab task creation based of the analyzed messages.

Heterogeneous Network (HetNet) deployment has been considered as the main approach to boost capacity and coverage in Long Term Evolu-tion (LTE) networks in order to fulfill the huge future demand on mo-bile broadband usage. In order to study the improvement on network performance, i.e. capacity, coverage and user throughput, from pico cell densification in LTE HetNets, a network densification algorithm which determines the placement locations of the pico sites based on pathloss has been designed and applied to build several network models with different pico cell densities. The study has been taken based on a real radio network in a limited urban area using an advanced Matlab-based radio network simulator. The simulation results show that the network performance generally is enhanced by introducing more pico cells to the network.

Wireless networks have become a necessity with the increased mobility in human life. From cellular telephony to the Internet, all types of communication are now provided over wireless networks. However, to offer wireless network coverage over an area requires a potentially expensive infrastructure deployment. Such deployment requires base stations which until now have been completely proprietary to the equipment vendors. Moreover, proprietary equipment is almost always costly and offer less flexibility than standardized modular solutions. This situation results in a high cost for network upgradation and hinders network development. A remedy is available via modularization, hence the Open Base Station Architecture Initiative (OBSAI) is trying to modularize and standardize one of the most expensive elements of the wireless infrastructure, the base station. OBSAI standards aim to modularize the base station architecture and enable true interoperability among the various modules. However, the goal has not yet been achieved due to some features of the standard. This thesis project has studied the standards and pointed out some areas that must be concentrated upon when performing interoperability tests. It also proposes several standards amendments to foster greater interoperability among the modules of a base station. This study focuses on the RP3 interface of the OBSAI specification with the goal of making truly inter-operable baseband and RF modules, thus commoditizing the modules. The result is expected to be lower cost, greater interoperability, faster time-to-market, and more cooperative research. / Langattomat laajakaistaverkot ovat tulleet välttämättömäksi osaksi liikkuvien ihmisten elämää. Lähes kaikki kommunikaatiotarpeet äänipuheluista internettiin pystytään toteuttamaan langattomien verkkojen avulla. Kuitenkin jotta langattomilla verkoilla pystytään tarjoamaan täysi peittävyys yli maan, se vaatii varsin kalliita investointeja verkkoinfrastruktuuriin. Langattomien verkkojen investoinnit koostuvat suurelta osin tukiasemista, jotka tähän asti ovat olleet kullakin verkkotoimittajalla täysin omanlaisensa toteutus. Kun jokainen verkkotoimittaja toteuttaa kaikki tukiaseman osat erilailla, se tarkoittaa että kutakin tukiaseman osia valmistetaan suhteellisesti pienempiä määriä ja sitä myötä niistä tulee mahdollisesti kalliimpia verrattuna standardoituhin modulaarisiin tukiasemaratkaisuihin. Nykyinen tilanne siis osaltaan johtaa siihen että verkkojen rakentaminen ja päivittäminen on kallista. Eräs ratkaisu tähän ongelmaan on tarjolla modulaarisessa tukiasemaratkaisussa ja siksi OBSAI, Open Base Station Initiative, pyrkii modulaarisoimaan ja standardoimaan yhden kalliimmista verkkoinfrastruktuurin osista, tukiaseman. OBSAI standardi pyrkii modularisoimaan tukiasema-arkkitehtuurin ja mahdollistamaan todellisen yhteensopivuuden tukiaseman eri osien välillä. Tätä todellista yhteensopivuutta ei ole vielä täysin pystytty toteuttamaan, johtuen tietyistä standardin epätarkkuuksista. Tässä lopputyössä on analysoitu OBSAI standardia ja identifioitu alueet, joihin pitää keskittyä, kun modulien välistä yhteensopivuutta testataan. Työn lopputulemana myös ehdotetaan useita parannuksia ja muutoksia standardiin, jotta todellinen yhteensopivuus modulien välillä saavutetaan. Painopiste lopputyössä on OBSAI standardin RP3 rajapinta, joka määrittelee kantataajuusosan (BB) ja radiotaajuusosan (RF) välisen rajapinnan. Kun OBSAI standardia saadaan parannettua työssä ehdotetuin toimenpitein, lopputuloksena on oletettavasti alhaisempi tukiaseman kokonaiskustannus, mahdollisuus käyttää yhteensopivia moduleita eri valmistajilta, nopeampi tuotteiden markkinoille vienti sekä parantunut tutkimusyhteistyö eri yritysten välillä. / Trådlösa nät har blivit en nödvändighet i vår allt mer mobila livsstil. Från mobiltelefoni till Internet, trådlösa nät erbjuder många typer av kommunikation. Men att erbjuda trådlös täckning i ett område kan kräva installation av en mängd dyrbar telekomutrustning. En sådan utbyggnad kräver basstationer som fram till nu har varit patentskyddade av respektive leverantör. Och patentskyddad utrustning är oftast både dyrare och mindre flexibel jämfört med standardiserade modulära lösningar. Resultatet är höga kostnader för att uppgradera näten och att utvecklingen försvåras. Ett botemedel är användningen av standardiserade moduler. Därfär försöker Open Base Station Architecture Initiative (OBSAI) att standardisera moduler i ett av de dyraste nätelementen i trådlösa nät, basstationen. OBSAI har som mål att dela upp basstationen i definierade moduler och möjliggöra fullständig interaktion mellan olika moduler. Men på grund av vissa egenskaper hos standarden har detta inte lyckats. Denna studie har undersökt standarden och pekar på områden som man måste fokusera på när man utför tester mellan moduler. Dessutom föreslås flera tillägg till standarden för att möjliggöra bättre interaktion mellan basstationens moduler. Studien fokuserar på RP3- gränssnittet med målet att möjliggöra standardiserad interaktion mellan basbands- och radio-moduler, så att dessa moduler kan kommerisialiseras. Det förväntade resultatet är lägre kostnader, bättre interaktion mellan moduler, snabbare marknadsintroduktion och mer samarbete inom forskning och utveckling.

The market penetration of mobile access devices with multiple network interfaces has increased dramatically over the last few years. As a consequence, the quest for a widespread multi-path transport protocol that takes advantage of all available interfaces simultaneously to increase data throughput and improve robustness, has received considerable attention. One prominent protocol introduced by the IETF is Multipath TCP (MPTCP). MPTCP is an extension to the predominant single-path transport protocol, the Transport Control Protocol (TCP) that enables multihomed devices to aggregate available resources transparently to the applications. Combining multiple radio access technologies, like LTE and Wi-Fi, with diverse characteristics in terms of transmission rates and fluctuations opens for novel challenges that may disrupt and even harm the data throughput. Therefore MPTCP must take path heterogeneity into account. For MPTCP to supersede single-path TCP it is required that MPTCP always achieve at least the throughput of the best individual TCP path. This thesis investigates if MPTCP with uncoupled congestion control fulfills this condition, and if so, how much it improves the throughput. By examining the protocol in a deterministic emulated environment defined by the characteristics of LTE, we conclude two key factors impacting the outcome: the download size and the difference in characteristics between the paths. Our experiments show that MPTCP overall fulfills this task, especially during path homogeneity with near aggregated results. But we also show that MPTCP may decrease data throughput with 16% compared to TCP during path heterogeneity. Hence MPTCP does not always fulfill the goal of throughput. We therefore conclude further intelligence is needed for the packet scheduling mechanism to avoid throughput degradation in the initial phase of a transmission.