Dissertations / Theses on the topic 'UMTS'
To see the other types of publications on this topic, follow the link: UMTS.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'UMTS.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Oliver, Kathryn E. "UMTS network optimisation." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/54561/.
Full textAbstract:
Network operators desire effective, pragmatic solutions to instances of the cell planning problem in order to improve their quality of service, enhance network coverage and capacity capability, and ultimately increase company profits. Previ ous cell plans have been constructed manually but these methods do not produce the best network configuration. More reliance has since been placed on automated cell planning to produce effective solutions. The introduction of the Universal Mobile Telecommunication System (UMTS) emphasizes the need for high perfor mance planning tools. Motivated by a discussion of the literature concerning cell planning, an existing model for Global System for Mobile Communication (GSM) is modified to take account of the requirements of UMTS networks. A suite of test cases is created using a purpose-built problem generator, including problems with a range of site and traffic distributions for rural, suburban and urban markets. Traditionally, cell planning has been seen purely as an optimisation problem, neglecting the pre-optimisation stage of network dimensioning. This thesis inves tigates the effect of network dimensioning as a precursor to optimisation demon strating the benefits of cell planning in three stages consisting of site estimation, site selection and optimisation. The first stage, site estimation, utilises previously published lower bounding techniques to provide a means of approximating the number of sites required to meet capacity targets in the uplink and downlink. Site selection compares random selection to three newly developed algorithms to make effective automatic selections of sites from a candidate set. The final optimiza tion phase presents a framework based on the tabu search meta-heuristic capable of optimising the dimensioned network designs with respect to the representative operational scenarios. Multiple traffic snapshot evaluations are considered in the optimisation objective function.
2
Boujemaa, Hatem. "Récepteur UMTS optimisé." Paris, ENST, 2001. http://www.theses.fr/2001ENST0023.
Full textAbstract:
L'apparition de nouveaux services nécessitant de comminiquer à des débits de plus en plus élevés et avec une qualité meilleure est à I'origine de l'émergence de la troisième génération de radio-mobiles. En Europe. Ies caractéristiques de cette nouvelle génération sont entrain d'être spécifiées dans la norme UMTS ("Universal Mobile Télécommunication Standard"). Dans ce mémoire de thèse, nous avons traité divers thèmes clés de la norme UMTS. Nous avons commencé par développer les structures de deux implémentations du récepteur en râteau permettant de récupérer une grande partie de la diversité offerte par le canal multitrajets. Le premier récepteur est celui qu'on utilise d'habitude et consiste à combiner les sorties de corrélateurs synchronisés sur les trajets les plus significatifs. Afin de contourner le problème d'estimation des délais des trajets nous avons étudié également une implémentation à temps discret du récepteur en râteau. Cette approche est basée sur une estimation globale du produit de convolution des réponses impulsionnelles du canal de propagation et du filtre de mise en forme. Ensuite, nous avons traité les problèmes engendrés par l'interférence entre symboles qui apparaîssent pour des services à haut débit. Ce thème est d'une importance primordiale pour l'UMTS dont le pari est justement de pOUVOir assurer de tels services. Après cela, nous avons étudié puis optimisé la procédule de contrôle de puissance qui permet de lutter contre l'effet des épanouissements. Enfin. Nous avons recherché la meilleure stratégie d'allocation de l'énergie du canal RACH ("Random Access Channel") afin de réduire l'intertérence qu'il génère.
3
Srdínko, Milan. "Model systému UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217676.
Full textAbstract:
Spread Spectrum Communication techniques have been widely used in mobile and wireless communications. They have very beneficial features like antijam and security (noise-like character, pseudorandom codes usage). At first, the features of Spread Spectrum systems are described with emphasis on the Direct Sequence Spread Spectrum (DS-SS) scheme. Main specifications of UMTS system are also introduced. The goal of this thesis was to create the model of a physical layer UMTS suitable for investigation of disturbing signals influences in Matlab Simulink. This model was used to measure how the Bit error rate (BER) is affected by the Processing gain and the Signal-to-noise ratio. Finally, two important charts which describe the relation of Bit error rate versus the Processing gain and the Signal-to-noise ratio have been plotted.
4
Boujemaa, Hatem. "Récepteur UMTS optimisé /." Paris : École nationale supérieure des télécommunications, 2001. http://catalogue.bnf.fr/ark:/12148/cb38838443s.
Full text
5
De, Bruijn Marc. "Marktchancen für UMTS-Dienste." St. Gallen, 2004. http://www.biblio.unisg.ch/org/biblio/edoc.nsf/wwwDisplayIdentifier/01649102001/$FILE/01649102001.pdf.
Full text
6
Datta, Subhalakshmi. "UMTS radio network optimisation." Thesis, University of Surrey, 2010. http://epubs.surrey.ac.uk/843921/.
Full textAbstract:
Radio network planning and optimisation include tasks such as propagation prediction, performance evaluation, and configuration optimisation. Unlike Time Division Multiple Access (TDMA) based systems, the network performance of Third Generation (3G) cellular systems cannot be based on signal predictions only. The maximum achievable path loss in a Wideband Code Division Multiple Access (WCDMA) cell is dependent on the cell load, which creates a complex trade-off between coverage and capacity. Given a user distribution, network performance calculation involves optimisation of transmit powers taking into consideration the location of each user. This mathematical problem is Non-deterministic polynomial time (NP) hard even for small and simplified instances and the solution process is time consuming. This research focuses on methods that allow fast and intuitive performance evaluation for WCDMA networks. In this work, a novel Semi-Analytical Model (SeAM) for user-capacity calculation, based on static snapshot input, is proposed. The model uses a centralised approach that allows the identification of users with the highest impact on link quality. These users can be removed from the system before going through the iterative procedure of solving the NP hard problem. Therefore, this combined power control and user removal algorithm converges to the optimum solution in a lower number of iteration steps compared to a conventional stepwise user removal scheme or a distributed system level simulation. This thesis also documents research findings in the area of network performance analysis using realistic instances, classical propagation models, and varying traffic scenarios. Performance indicators calculated on the basis of analytical methods are compared with results generated by an advanced WCDMA simulator in order to estimate the accuracy and validate assumptions related to analytical modelling of the WCDMA air-interface. Network planners are generally faced with the challenge of controlling network coverage and capacity at minimum infrastructure cost while maintaining user satisfaction. In this thesis, a configuration optimisation algorithm, based on a Simulated Annealing framework, is proposed for automatic planning of Node B locations and antenna configurations. The automatic planning software is implemented using a WCDMA simulator and SeAM, respectively, as core algorithm for network performance evaluation and cost function calculation.
7
Havlíček, Karel. "Optimalizace přístupové sítě UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217447.
Full textAbstract:
This master’s thesis deals with a UMTS radio access network optimization, containing radio interface analysis, services and procedures description, ways to correct parameters calculations and settings and other issues necessary for a correct access network operation. The goal is effective network operation, minimum costs and maximum performance and flexibility of the network. The optimization during system operation is important because of the system character. The UMTS system uses the WCDMA technology, where particular users share the same frequency band and they are distinguished from one another via code sequences. The capacity of such a system is then given by the interference level - each particular user increases the interference level by the value corresponding to his transmit power. The maximum cell capacity is determined by the maximum interference level at which users can still operate with required services, so it is related not only to the number of users, but also to their bit rate. The optimization allows effective usage of the system for different services with different requirements. The main optimization tool is the radio resource management, containing number of algorithms, such as admission control, which decides the acceptance or rejection of a new user demanding certain service, power control, which ensure that users transmit with a minimal power sufficient for required service, handover and cell selection algorithms etc. The major parameter used by these algorithms is a cell load factor, which is related to the interference level margin. There are several methods for the load factor estimation and some of them are described in this work. Some other optimization techniques are mentioned here, too. This work also contains a laboratory exercise proposal for radio resource management introduction using the OPNET Modeler network simulation tool.
8
Spěváček, Jiří. "Plánování přístupových sítí UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217448.
Full textAbstract:
The master thesis is focused on the Universal Mobile Telecommunications System (UMTS) - the third-generation cell phone technology. The first part describes the development of mobile networks and the structure of the UMTS. The second part, the main part of the thesis, is focused on the planning procedure of the UMTS access network. It consists of an explanation of the general planning procedure and a specific project designing the coverage of Pelhřimov surroundings. The final part of the thesis contains a laboratory problem including instructions.
9
Kavan, Radovan. "QoS v systému UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218026.
Full textAbstract:
This thesis treats of QoS (Quality of Service) in UMTS system. The term quality of service is frequently used, recently, however not only in computer networks, but also more and more in mobile networks also. Present system of 2nd generation (2G) GSM enables only limited exploitation of QoS function. System UMTS is a system of 3rd generation (3G) already and contains quality of service in greater measure which is ensured with number of algorithms and functions. Individual QoS functions enable effective utilization of radio interface, support maintenance of planned coverage and offer high spectral efficiency. Functions that cater to quality of service are called RRM functions (Radio Resource Management). There exist five basic functions in UMTS system that are Admission control (AC), Power control (PC), Load control (LC), Handover control (HC) and Packet scheduler (PS). These functions are responsible for control of network access, control of power, control of network load, control of handover and packet (bit rate) scheduling. Last three functions are usually collectively designated as Congestion control, control of network overload. UMTS layer model, differentiation of services, traffic classes and 3GPP concept are also discussed. In thesis the attention is piad to Admission control algorithm – control of network access – in the uplink direction and to different ways of load (in the cell) modeling. Individual approaches are simulated in MATLAB. A possibility of using algorithm in the real system is discussed in conclusion.
10
Булашенко, Андрій Васильович, Андрей Васильевич Булашенко, Andrii Vasylovych Bulashenko, and І. В. Забегалов. "Аналіз мережі третього покоління UMTS." Thesis, Сумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/47185.
Full textAbstract:
Радіомережа стандарту UMTS (Universal Mobile Telecommunications System) –
система мобільного зв’язку третього покоління, що розроблена у межах IMT2000
Європейським Інститутом Стандартів Телекомунікацій (ETSI) для
впровадження 3G у Європі.
11
Videira, António Germano Paiva. "Difusão e multicast em UMTS." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/1936.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesDesde os primórdios da existência humana que existe a necessidade de comunicar. O ser humano desde então tem procurado meios de comunicação mais rápidos e eficientes. A eficácia da comunicação bem como a partilha de conteúdos quando vários clientes requerem a mesma informação no mesmo instante de tempo constituem o tema central deste trabalho, permitindo utilizar os recursos de rede dos operadores móveis de uma forma muito mais optimizada. Actualmente as redes UMTS usam a transmissão em modo unicast que não é uma solução escalável para a distribuição de conteúdos em tempo real, distribuídos em massa, como é o caso da Mobile TV. A release 6 da norma UMTS introduziu pela primeira vez capacidades de difusão e multicast nas redes móveis através do serviço MBMS. Com isto podemos ter aplicações que permitem às redes móveis disponibilizar serviços do tipo multicast e broadcast nos telemóveis que são considerados por muitos como as killer applications que há muito se procura, podendo contribuir para o aumento da receita por utilizador dos operadores. Este trabalho começa com a apresentação do estado da arte das comunicações móveis seguido da apresentação de uma plataforma de distribuição de conteúdos que vai ser evoluída na sua arquitectura e funcionalidades. O principal objectivo é a especificação de um BM-SC e fazer um estudo aprofundado do MBMS. Com vista à validação e avaliação dos conhecimentos foi contruido um demostrador com especial enfoque para o protocolo entre o BM-SC e os distribuidores de conteúdos. No final, como conclusão, são apontadas as direcções possíveis para a evolução do BM-SC. ABSTRACT: Right from the beginnings of human existence, there has always been a human need to communicate. Since then, humans have found the means of communicating more directly and efficiently. Nowadays, clients also make much better use of the resources at their disposal by being able to share the same information at the same time and this is the focus of this research project. At the moment, UMTS networks transmit via the Unicast mode which is not a viable solution to send contents in real time, as is the case with Mobile TV. For the first time, the UTMS release 6 makes it possible to broadcast and multicast in mobile networks through the MBMS service. MBMS provides us with an application that allows mobile networks to get multicast services via their mobile phones. Many consider these to be the so-called ‘killer applications’ that have been long awaited because they are able to increase the operator’s average revenue per user. This work begins with a presentation of state-of-the-art mobile telecommunications followed by a brief introduction to a platform of content distribution which is going to be further developed and enhanced both in terms of its structure and its functions. The main objective of this work is first to specify and then build a BM-SC and then to carry out some more profound research into MBMS. With the aim of validating and evaluating this knowledge, a demonstration model has been built in order to highlight the specifications of the BM-SC and the content distributors. At the end and to conclude this study, we will provide some pointers to show how we believe the BM-SC will develop and in which directions it will progress.
12
Trojáček, Jaroslav. "Rozbor signalizace u sítí UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217270.
Full textAbstract:
Master thesis is focused on signalling analysis of third-generation mobile network UMTS. In first part of master thesis is described a question of standard IMT-2000, introduces the principles of the WCDMA air interface, gives a wide overview of the UMTS system architecture and signal processing. In second part of master thesis is described a question of signalling analysis, including general protocol model for UTRAN terrestrial interfaces. This chapter is focused on elementary procedures, Radio Resource Management procedure examples, Mobility Management procedure examples and Call Control procedure examples in the first place. Last chapter of master thesis is focused on radio network planning of UMTS with practical location of basic station Node-B.
13
Kokeš, Roman. "Multicastové směrování v UMTS sítích." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217544.
Full textAbstract:
This Master thesis is about multicast in mobile network 3rd generation UMTS(Universal Mobile Telecommunacitions System). UMTS network primary designs for data transfers and supports new services as real-time transfers of multimedia streams. This is reason why mobile network was equiped also with multicast service. When a lot of users want to receive same data (e.g. tv program) the network excessives load of transmission same data and the server have to keep connection to each user. Group 3GGP developed multicast service for UMTS, which name is MBMS (Multimedia Broadcast and Multicast Service). Thesis analyses function of this service in mobile network. First part describes basic principles of UMTS network and its structure. Next part focuses on change of main node (SGSN and GGSN) and of new node BM-SC(Broadcast-Multicast Service Center). This new node is main node for control of multicast transmission. BM-SC connects to server which provides multicast data for users and provisions individual phase of MBMS session. It was created new procedure which supports multicast session (e.g. Activate MBMS service). Next part focuses on GPRS Tunneling Protocol (GTP). This protocol is used for transfers control and user’s data in tunnels inside core network. This part describes structure of data and control messages. Last part analyzes multimedia transfers in UMTS with program Opnet Modeller.
14
Fabricius, Marián. "Zajištění QoS v UMTS síti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218065.
Full textAbstract:
Diploma thesis deals with assign and distribution quality of service in mobile UMTS telecommunication networks. The project consists of two parts, theoretical and practical. Theoretical part of the project is focused to familiarize with functionality of the UMTS network with the main aspect at admission mechanism in radio part of the network as well as quality of service assign mechanisms according to service demands within core network of UMTS. Practical part of the project is given to simulation program OPNET Modeler and its capabilities in network design and testing various parameters of UMTS network with implementation quality of service mechanism. As the asset of diploma thesis becomes designed functional prototype of UMTS network with various options for individual settings user equipment as well as fixed mobile networks nodes.
15
Xu, Kai. "Radio resource management for satellite UMTS : dynamic scheduling algorithm for a UMTS-compatible satellite network." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/5685.
Full textAbstract:
The third generation of mobile communication systems introduce interactive Multicast and Unicast multimedia services at a fast data rate of up to 2 Mbps and is expected to complete the globalization of the mobile telecommunication systems. The implementation of these services on satellite systems, particularly for broadcast and multicast applications to complement terrestrial services is ideal since satellite systems are capable of providing global coverage in areas not served by terrestrial telecommunication services. However, the main bottleneck of such systems is the scarcity of radio resources for supporting multimedia applications which has resulted in the rapid growth in research efforts for deriving efficient radio resource management techniques. This issue is addressed in this thesis, where the main emphasis is to design a dynamic scheduling framework and algorithm that can improve the overall performance of the radio resource management strategy of a UMTS compatible satellite network, taking into account the unique characteristics of wireless channel conditions. This thesis will initially be focused on the design of the network and functional architecture of a UMTS -compatible satellite network. Based on this architecture, an effective scheduling framework is designed, which can provide different types of resource assigning strategies. A functional model of scheduler is defined to describe the behaviours and interactions between different functional entities. An OPNET simulation model with a complete network protocol stack is developed to validate the performance of the scheduling algorithms implemented in the satellite network. Different types of traffic are considered for the OPNET simulation, such as the Poisson Process, ONOFF Source and Self Similar Process, so that the performance of scheduling algorithm can be analyzed for different types of services. A novel scheduling algorithm is proposed to optimise the channel utilisation by considering the characteristics of the wireless channel, which are bursty and location dependent. In order to overcome the channel errors, different code rates are applied for the user under different channel conditions. The proposed scheduling algorithm is designed to give higher priority to users with higher code rate, so that the throughput of network is optimized and at the same time, maintaining the end users' service level agreements. The fairness of the proposed scheduling algorithm is validated using OPNET simulation. The simulation results show that the algorithm can fairly allocate resource to different connections not only among different service classes but also within the same service class depending on their QoS attributes.
16
Xu, Kai J. "Radio Resource Management for Satellite UMTS. Dynamic scheduling algorithm for a UMTS-compatible satellite network." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/5685.
Full textAbstract:
The third generation of mobile communication systems introduce
interactive Multicast and Unicast multimedia services at a fast data rate of
up to 2 Mbps and is expected to complete the globalization of the mobile
telecommunication systems. The implementation of these services on
satellite systems, particularly for broadcast and multicast applications to
complement terrestrial services is ideal since satellite systems are capable
of providing global coverage in areas not served by terrestrial
telecommunication services. However, the main bottleneck of such
systems is the scarcity of radio resources for supporting multimedia
applications which has resulted in the rapid growth in research efforts for
deriving efficient radio resource management techniques. This issue is
addressed in this thesis, where the main emphasis is to design a dynamic
scheduling framework and algorithm that can improve the overall
performance of the radio resource management strategy of a UMTS
compatible satellite network, taking into account the unique characteristics
of wireless channel conditions.
This thesis will initially be focused on the design of the network and
functional architecture of a UMTS -compatible satellite network. Based on
this architecture, an effective scheduling framework is designed, which
can provide different types of resource assigning strategies. A functional
model of scheduler is defined to describe the behaviours and interactions
between different functional entities.
An OPNET simulation model with a complete network protocol stack is
developed to validate the performance of the scheduling algorithms
implemented in the satellite network. Different types of traffic are
considered for the OPNET simulation, such as the Poisson Process, ONOFF
Source and Self Similar Process, so that the performance of
scheduling algorithm can be analyzed for different types of services.
A novel scheduling algorithm is proposed to optimise the channel
utilisation by considering the characteristics of the wireless channel, which
are bursty and location dependent. In order to overcome the channel
errors, different code rates are applied for the user under different channel
conditions. The proposed scheduling algorithm is designed to give higher
priority to users with higher code rate, so that the throughput of network is
optimized and at the same time, maintaining the end users¿ service level
agreements. The fairness of the proposed scheduling algorithm is
validated using OPNET simulation. The simulation results show that the
algorithm can fairly allocate resource to different connections not only
among different service classes but also within the same service class
depending on their QoS attributes.Inmarsat Global Ltd. BGAN and the European Space Agency (ESA)
17
Hameed, Farhan. "Rate Scheduling for HSDPA in UMTS." Thesis, Högskolan Dalarna, Datateknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:du-3734.
Full textAbstract:
The introduction of a new technology High Speed Downlink Packet Access (HSDPA) in the Release 5 of the 3GPP specifications raises the question about its performance capabilities. HSDPA is a promising technology which gives theoretical rates up to 14.4 Mbits. The main objective of this thesis is to discuss the system level performance of HSDPAMainly the thesis exploration focuses on the Packet Scheduler because it is the central entity of the HSDPA design. Due to its function, the Packet Scheduler has a direct impact on the HSDPA system performance. Similarly, it also determines the end user performance, and more specifically the relative performance between the users in the cell.The thesis analyzes several Packet Scheduling algorithms that can optimize the trade-off between system capacity and end user performance for the traffic classes targeted in this thesis.The performance evaluation of the algorithms in the HSDPA system are carried out under computer aided simulations that are assessed under realistic conditions to predict the results as precise on the algorithms efficiency. The simulation of the HSDPA system and the algorithms are coded in C/C++ language
18
Sumanasena, Muddarage Abhaya Kumarasiri. "Adaptive physical layer for satellite UMTS." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/843328/.
Full textAbstract:
Satellite resource management efficiency has been identified as one of the key factors in the commercial success of mobile satellite systems, since optimisation of all link budget elements is crucially important in order to make the most out of the satellite limited resources (bandwidth, power) which in turn have a direct impact on the cost of the system. The compensation techniques used in order to overcome the fading effects experienced in the link are generally applied by considering the worst-case channel conditions, resulting in inefficient utilisation of the transmission power as well as frequency spectrum. There is no dynamic control adaption used in current mobile satellite systems except simple power control. In addition, a single scheme is neither capable of providing an optimum solution for fade mitigation nor closing the link budget at all times. Therefore, it is necessary to use more than one technique at a time which offers the best solution in terms of spectrum and power efficiency. The efficiency of conventional systems, therefore, can be improved if it has the ability to match the effective user bit rate to the channel conditions by using a hybrid scheme. Hence, the aim of our work is to develop a physical layer by using a hybrid scheme, which results in higher throughput under favourable channel conditions. This technique also introduces a reduction of the data rate during bad channel conditions without the need to increase the transmitted power significantly. The novelty of this research work is centred on the switching mechanism used for such adaptations. For the first time, we propose an adaptive system based on the Rice factor variation. The suitability of this parameter for the proposed adaptive system is investigated first by considering the real time variation in the environment. We are proposing a feed back type of system in which the receiver estimates the Rice factor and sends it to the transmitter. Upon receiving this information, the transmitter selects the optimum modulation and coding scheme for the transmission in order to improve spectral and power efficiency of the system. In order to develop an adaptive physical layer, the main issues related to mobile satellite systems should be identified. Therefore, the key differences between the terrestrial and satellite mobile communication systems are presented at the beginning. A brief description about T/S-UMTS and the air interfaces proposed for standardisation of S-UMTS are presented and compared in the following chapter. Subsequently, a suitable baseline model was chosen and the simulation aspects are presented. The following chapter presents some of the parameters that have to be estimated in order to develop an adaptive physical layer. The performance evaluation of adaptive modulation and coding is presented in the last chapter. Key words: S-UMTS, SW-CDMA, Adaptive modulation and coding. Rate matching, SNR estimation, modulation detection. Rice factor estimation. Histogram comparison. Re-encoding.
19
Machauer, Ralf [Verfasser]. "Multicode-Detektion im UMTS / Ralf Machauer." Karlsruhe : KIT-Bibliothek, 2002. http://d-nb.info/1013806395/34.
Full text
20
Nourizadeh, Hamed. "UMTS cellular network with relaying concept." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/844065/.
Full textAbstract:
Wideband Code Division Multiple Access (WCDMA) is one of the technologies for third generation systems. In a CDMA system, all users interfere with each others, therefore the CDMA system is interference limited. The users, who suffer from a strong shadow effect or that are far away from the BS, need more power to reach it. In this case, the users may transmit at their maximum allowed power without satisfying their Quality of Service. Therefore, this would leave some mobiles in outage and also create too much interference to the neighboring cells. One-way to counter this problem and therefore to improve the capacity is to increase the number of BSs. But this solution cannot be efficient as it significantly increases the network infrastructure cost. Alternative techniques that involve less planning and are quick to deploy appear to be more advantageous. Relaying is one of these techniques and is growing in importance for future wireless systems. In this thesis, a new radio access network based on combinations of multi-hop and star-topology architectures is proposed. The main objective of this thesis is to demonstrate achievable capacity gains under various relaying criteria compared with no-relaying (conventional) cellular architecture. In this new architecture, some intermediate nodes (mobile or fixed) located between the originating terminal and the BSs are used for the purpose of retransmitting the original packets. We show that under specific criteria and conditions the multihop concept indeed yields capacity gains. A number of different scenarios are defined and their relative performances are fully evaluated using an accurate dynamic system-level simulator. The capacity gains are compared to the case of no relaying/hopping. To demonstrate the achievable capacity gains, we use UMTS FDD and TDD modes. The proposed concepts and criteria for relaying are generic enough to be used with current and future radio access technologies. The results show that under certain conditions an uplink capacity gain of 30-40% is readily achievable with the multihop architecture.
21
Knoche, Klaus. "Empfänger-Strukturen für die UMTS-Abwärtsstrecke." Aachen Shaker, 2009. http://d-nb.info/995162085/04.
Full text
22
Knutsson, Björn. "Simulation of radio resource management for UMTS." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2364.
Full textAbstract:
A current trend in the information society is that traditionally fixed computing resources are made available to mobile users. Most of the existing techniques for communication have been developed for stationary computing, and they must be adapted to the different connection properties of the mobile environment. One of the emerging mobile computing environments is the Universal Mobile Telecommunication System, UMTS. This system places demands on the quality of service that is provided to data flows, which requires resource management in the connection network. The most scarce resources in this system is the radio resources. The easiest way to conduct research in new and adapted techniques for communication is to perform simulations. Management of resources places restrictions on connections, and to get reliable results during simulations it must be included in the simulated environment. The thesis discusses and builds a basis for development of UMTS radio resource management in the network simulator ns-2. A limited version of UMTS radio resource management is added to ns-2 and evaluated.
23
Sureshkumar, Meena. "Undersökning av mätsystem för UMTS (3G) telefoner." Thesis, Linköping University, Department of Science and Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7725.
Full textAbstract:
Företaget Flextronics AB i Linköping testar moderna mobiltelefoner för tillverkares räkning. Som examensarbete har jag fått företagets uppdrag att utvärdera och förbättra deras testsystem DVT-UMTS (3G).
DVT-UMTS är ett komplext system av komponenter, och man misstänker att dessa stör varandra inbördes, vilket i sin tur kan ge felaktiga mätresultat.
Beträffande mottagarsidan hos en mobiltelefon tror man att DVT-UMTS p g a störningar, s k intermodulationsprodukter, uppvisar bitfelshalter i testet Rx Out of band blocking. Komponenter som kan tänkas ge störningar är continuous wave-generator och basstationssimulatorn. Antennanslutningen bortses från i undersökningen. Kontroll av CW-generatorn sker med hjälp av lågpassfilter, riktkopplare och dämpare. Kontrollen visar att den är orsak till bitfel men inte ensam orsak. Basstationssimulatorn kontrolleras med hjälp av högpassfilter, riktkopplare och varierade kabellängder. Även denna visar sig ge upphov till bitfel.
Bitfel orsakade av intermodulationsprodukter från CW-generatorn kan reduceras med lågpassfilter och dämpare. Motsvarande problem hos basstationssimulatorn kan åtgärdas med högpassfilter och varierade kabellängder.
Kvarstående bitfel är acceptabla enligt specificerade krav från det internationella samarbetsorganet 3GPP.
Mobiltelefonens sändarefunktion testas med programmet Tx Spurious emission, där otillåtet höga dämpningsnivåer kan ge problem. Dessa nivåer beror av signalvägarna mellan testad enhet och spektrumanalysatorn. Med hjälp av gordon, darlingtontransistor och switch kan signalvägarna optimeras. En alternativ testuppkoppling på DVT-UMTS, innehållande switch med styrprogram, ger dämpningsnivåer innanför specificerade gränser.
24
Flohrer, Marco. "UMTS - Mehr als nur zum Telefonieren gut." Universitätsbibliothek Chemnitz, 2001. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200100471.
Full textAbstract:
Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur "Rechnernetze und verteilte Systeme" der Fakultaet fuer Informatik der TU Chemnitz.
Workshop-Thema: Mobilitaet
Technik und Anwendungsmöglichkeiten des Mobilfunkstandards der 3. Generation unter Einbeziehung von Vorgänger-, Alternativ-, sowie Nachfolgesystemen.
25
Widiawan, Anggoro Kurnianto. "Characteristics and performance of airplane-based UMTS." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/843124/.
Full textAbstract:
Since the first generation of mobile communication systems (IG), mobile services have been relying on ground-based infrastructures. However, the increasing mobile services demand on higher frequencies and higher data rates has been urging the ground-based systems to have far more sites. With a limited number of appropriate sites, achieving seamless coverage and supporting high user mobility may not be cost effective. On the other hand, satellites have been operated to gain regional or global mobile communications coverage and offer high user mobility. Yet these space-based infrastructures have high latency (i.e. propagation delays) and propagation loss that substantially limit the system capacity and make the user terminals expensive. Hence, for about a decade, aerial platforms have been studied and recognised as potential sky-based infrastructures as part of the future mobile communications. In the year 2000, High Altitude Platform Station (HAPS) has been accepted as an alternative infrastructure for the third generation of mobile communication systems (3G) such as UMTS. However, most of the attention is currently more towards the development of sophisticated platform technologies that have long endurance and capable of offering high system capacity. Consequently, the implementation and desperately required proof of the concept are significantly delayed. Furthermore, many studies have covered the exploitation of the strength of aerial platforms but none has comprehensively addressed the challenging properties of such platforms. Therefore, instead of waiting for the maturity of the platform technologies to fit with the mobile communications requirements, in this work airplane (an existing aerial platform) is selected as infrastructure for UMTS. Apart from the maturity of the airplane technology and the ultra-fast deployment features for emergency situations, airplanes also resemble the most challenging features of aerial platforms that are also addressed in this thesis. Severe atmospheric disturbance, high airplane speed, and short endurance are identified as the main features of Airplane UMTS. These features are realistically incorporated into an Airplane UMTS system level simulator, which is developed for the study of the characteristics and performance of the system in terms of Doppler, coverage, interference, coexistence with ground-based system, and airplane handover. The results show that the viability of Airplane UMTS is very encouraging. The Doppler rates are less than the ones of the benchmark system, ground-based UMTS, although the Doppler shifts are higher due to the mobility of the airplane. The airplane attitude does not have significant effects to the system coverage but it does affect the handover performance particularly for a system with fixed mounted multibeams antenna. The overall interference in the system is also affected by the airplane mobility, but it is still better than the ground-based system. Airplane UMTS can also coexist very well with the ground-based UMTS as a neighbouring or even as an overlay system. The short endurance problem can be overcome by the implementation of the proposed smooth airplane handover technique.
26
Niemeier, Stefan. "Die deutsche UMTS-Auktion : eine spieltheoretische Analyse /." Wiesbaden : Dt. Univ.-Verl, 2002. http://www.gbv.de/dms/zbw/355319993.pdf.
Full text
27
Benmimoune, Abderrahmane. "Handoff vertical entre réseau UMTS et WLAN." Mémoire, École de technologie supérieure, 2010. http://espace.etsmtl.ca/627/1/BENMIMOUNE_Abderrahmane.pdf.
Full textAbstract:
Un des principaux défis majeurs des prochaines générations des systèmes de communication
sans fil serait d'utiliser les ressources limitées des réseaux de communications d'une manière
efficace à l'effet d'obtenir une qualité et une capacité qui soient suffisantes pour faire face à
des demandes sans cesse croissante de services.
En effet, les besoins en bande passante des utilisateurs ont augmenté en raison des résultats
satisfaisants relevés des différentes applications telles que la vidéo et la navigation sur
Internet. Ceci a permit à plusieurs technologies de voir le jour et qui ne cessent de
s'améliorer afin de répondre aux besoins des utilisateurs. C'est notamment le cas des réseaux
hétérogènes qui servent à interconnecter les réseaux WIFI, GSM/UMTS et Satellitaires. Ce
progrès va permettre de répondre à la demande des utilisateurs en leurs offrants une très
grande mobilité dans le monde et une connexion n'importe où et n'importe quand.
L'objectif de ce présent mémoire de maîtrise est d'étudier la problématique de gestion de
mobilité entre les deux réseaux et de combiner ces techniques afin d'exploiter au mieux les
avantages inhérents à ces deux réseaux : cellulaire (UMTS) et local sans fil (WLAN) et de
pouvoir intégrer ces deux technologies de telle sorte que le changement de technologie soit
transparent.
Dans le cadre de la première partie de ce mémoire, nous avons traité particulièrement les
aspects de gestion de mobilité. Les deux différentes architectures d'interconnexion au
contexte des réseaux hétérogènes UMTS/WLAN sont relatées ainsi que différents algorithme
sont également mis en évidence principalement l'algorithme RSS, SNR et SINR
La plupart des contributions faites dans ce contexte prennent en considération juste la
maximisation du débit à travers les deux réseaux. Par contre la minimisation de nombre de
handoff durant un appel ou transfert de données joue un rôle très prépondérant, afin d'éviter
tout handoff inutile et d'éliminer par voie de conséquence l'effet ping-pong qui dégrade la
qualité de service.
C'est pourquoi, dans la seconde partie de notre mémoire, nous avons proposé une nouvelle
stratégie intégrant pour la réalisation d'un handoff vertical des utilisateurs mobiles entre les
deux réseaux tout en minimisant le nombre de handoff la probabilité de perdre des paquets
et d'atteindre un débit plus élevé avec meilleur prix conespondant. Dans ce cadre nous avons
présenté et nous avons testé plusieurs algorithmes de handoff et nous avons comparé ces
algorithmes avec notre solution proposée. Tous les algoritlmies entrepris ont été validés et
évalués par des simulations.
28
Pathak, Bhumin H. "Video transmission over UMTS mobile radio network." Thesis, Oxford Brookes University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432790.
Full text
29
Lim, Woo Lip. "Handover for high altitude platform station UMTS." Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250939.
Full text
30
Thomas, Nicholas J. "Techniques for mobile location estimation in UMTS." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/426.
Full textAbstract:
The subject area of this thesis is the locating of mobile users using the future 3rd generation spread spectrum communication system UMTS. The motivation behind this work is twofold: firstly the United States Federal Communications Commission (FCC) mandated the provision of user location into services in the United States of America due to the increasing number of emergency calls originating from unknown locations. Secondly the user location can enable a number of other potentially profit–making applications and services. These are generally thought to be the important new applications of the third generation mobile networks. The UMTS standard has now made provision for a time difference of arrival based mobile user location system in which the mobile measures time differences of arrival of received signals from surrounding base stations (BS’s). There are two main problems to such a technique: firstly the problem of detecting enough base stations to make a location fix, the so called ‘hearability’ problem. In spread spectrum systems all base stations transmit on the same bandwidth thus non–serving BS’s may not be detectable in normal operation. The second problem is non–line of sight (NLOS) propagation, in which time difference measurements (or any other measurement types) may be corrupted significantly, thus causing significant location error. The thesis of this work is that these two problems can be entirely overcome using spatial filtering of measurements and location estimates. Two constraints that are placed on the filtering algorithms are that the operation should be real time and that the precise distribution of NLOS errors is unknown (though certain key characteristics are exploited). A channel model is first developed, which specifically characterises line of sight and NLOS transitions as well as out of cell radio wave propagation. Several scenarios are then simulated. Slow moving users, low hearability and heavily NLOS conditions pose the biggest challenge. Spatial filtering is achieved by Kalman filters adapted to the problem, as well as simple averaging filters. Results show that improved location accuracy (to within FCC recommendations) is possible in all considered scenarios with spatial filtering as well as improved robustness to low hearability. The detection stage of the receiver is also analysed in detail and methods to improve hearability are presented. The performance of a hybrid location system using angle of arrival measurements of the mobile at the serving BS is also assessed. A fairly pessimistic model for the spread of NLOS errors is used, however significant location improvement is noted in several scenarios. Worst performance occurs in urban scenarios so finally a novel approach to user location is described which is robust to NLOS propagation conditions and also overcomes the hearability problem since only measurements at the serving BS are required. The technique, termed Scatterer Back Tracing (SBT), uses and requires multipaths to calculate the mobile location. Results suggest this SBT can provide extremely high location accuracy but is very sensitive to measurement noise.
31
Amador, António Jorge Vieira. "Distribuição de sinais UMTS sobre fibra óptica." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2026.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesO principal objectivo deste trabalho passa por descrever, demonstrar e simular um novo conceito de sistema de comunicação opto-electrónico. Este novo conceito de sistema de comunicação híbrido consiste em aplicar Code Division Multiple Access (CDMA) eléctrico num sistema Wavelength Division Multiplexing (WDM) óptico por forma a que a cada comprimento de onda seja atribuído um código ortogonal CDMA único antes da modulação do respectivo LASER. O objectivo desta abordagem é recuperar o canal de informação presente em cada comprimento de onda, depois de passar novamente para o domínio eléctrico num fotodíodo, sem a necessidade de utilizar filtros ópticos. Neste trabalho é feita a descrição detalhada deste conceito e das suas possíveis limitações, por simulação de um sistema de comunicações óptico que utiliza o conceito de referido, concluindo-se acerca da sua viabilidade. ABSTRACT: The purpose of this work is to describe and demonstrate a new concept of optoelectronic communications system. This new concept of a hybrid communication system consists of applying electric Code Division Multiple Access (CDMA) on a system using optic Wavelength Division Multiplexing (WDM) so that each optic carrier wavelength has a unique orthogonal CDMA code after each LASER is modulated. The main goal of this approach is to recover the information in each optical carrier wavelength without the need of optical filters. This is possible because, after converting the signals from the optic domain back to the electric domain the information of a given channel can be recovered using its unique orthogonal CDMA code. In this work, a detailed description of this new concept is made and its greatest limitations are asserted. Afterwards the system is simulated in order to confirm the concept’s viability.
32
Oh, Seong-Hoon. "Satellite-UMTS : specification of protocols and traffic performance /." Aachen : Mainz, 2005. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=3861301768.
Full text
33
Bing, Torsten. "Zeitduplexbasierte Mobilkommunikation, untersucht am Beispiel eines TD-CDMA-Mobilfunksystems." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963489496.
Full text
34
Mäder, Andreas. "Performance models for UMTS 3.5G mobile wireless systems." Würzburg Inst. für Informatik, Lehrstuhl für Verteilte Systeme, 2008. http://d-nb.info/999915061/34.
Full text
35
Modi, Nikunj. "Performance Evaluation of TCP Variants over UMTS Networks." Thesis, Uppsala University, Department of Information Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-98273.
Full textAbstract:
With the evolution of 3G technologies like Universal Mobile TelecommunicationSystem (UMTS), the usage of TCP has become more popular for a reliable end-to-end (e2e) data delivery. However, TCP was initially designed for wired networks and therefore it suffers performance degradation due to the radio signal getting affected by fading, shadowing and interference. There are many strategies proposed by the research community on how to improve the performance of TCP over wireless links such as introducing link-layer retransmission, explicitly notifying the sender of network conditions or using new variants of TCP.
As UMTS network coverage and availability are currently experiencing rapidgrowth, optimization of various internal components of its wireless network is very important. One of the optimization is the introduction of High Speed Downlink Packet Access (HSDPA). This architecture not only allows higher data rates but also more reliable data transfer by the introduction of Hybrid ARQ (HARQ). With this enhancement to the UMTS network, it becomes vital to see the performance of TCP in such a network. Therefore in this thesis, we try to evaluate two aspects of UMTS networks: first, the impact of HSDPA parameters like scheduling algorithm and RLC/MAC-hs buffer size on overall performance of TCP and second, to study the behavior of two categories of TCP rate and flow control: loss based and delay based. Our simulation shows that delay based TCP tends to perform better than loss based TCP in our selected scenarios. The simulations are performed using the network simulator NS-2 with an e2e network model for enhanced UMTS (EURANE).
36
Baloch, Yasir Ali. "UMTS Positioning Methods and Accuracy in Urban Environments." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73853.
Full textAbstract:
During the 2nd generation Global System for Mobile Communications (GSM) mobile communication, the focus of the mobile positioning was mostly on call setup and messaging. But the evolution of the 3rd generation Wideband Code Division Multiple Access (WCDMA) has changed the focus of mobile positioning. With the increase use of smart phones the mobile positioning is now extensively used for location based services (LBS’s). Mobile positioning becomes extremely important when the user requests any particular LBS, because it directly affects the communication and resource handling between the network and the mobile user MU. In order to reduce cost of messages exchange between the network and the MU it is really important that network should know the location of MU with minimum error. There are many positioning methods that are used today for MU location estimation. In this thesis database correlation method (DCM) is used as a positioning technique to estimate the MU location in the Universal Mobile Telecommunication System UMTS network. The thesis will also explain different penalty techniques for different scenarios that could be used to improve the MU location accuracy in the urban environment. By applying different penalty techniques the best positioning accuracy achieved for 67% of the measurements varies is 88m and for 95% it is 153m. Other penalty techniques results will be compared at the end in order to find the best penalty techniques that offer much improved location accuracy for MU.
37
Seeger, Ralf [Verfasser]. "Effiziente Konzepte für die UMTS-Abwärtsstrecke / Ralf Seeger." Aachen : Shaker, 2010. http://d-nb.info/1101184272/34.
Full text
38
Osman, Ammar. "Low-complexity OFDM transceiver design for UMTS-LTE." Thesis, Blekinge Tekniska Högskola, Avdelningen för signalbehandling, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3716.
Full textAbstract:
Over the past two decades the mobile wireless communication systems has been growing fast and continuously. Therefore, the standardization bodies together with wireless researchers and mobile operators around the globe have been constantly working on new technical specifications in order to meet the demand for this rapid growth. The 3rd Generation Partnership Project (3GPP) one of the largest of such standardization bodies, works on developing the current third generation (3G) mobile telecommunication systems towards the future 4th generation. Research towards meeting the higher demands for higher data rates was the main reason for the birth of an evolution technology towards the 4th generation mobile systems. This evolution to the current 3rd generation UMTS systems was given the name E-UTRA/UTRAN Long Term Evolution (LTE) by the 3GPP. This thesis research has been carried out at the Telecommunications Research Center (ftw.) in Vienna. It was conducted in the framework of the C10 project “Wireless Evolution Beyond 3G”. One of the fields of research within this project is to have a special focus on the OFDM modulation schemes that are discussed under the new evolution technology (LTE) of the UMTS mobile networks. Therefore, this thesis focuses mainly in analyzing the new requirements, and evaluating them by designing a low-complexity UMTS-LTE OFDM based transceiver. This thesis aims mainly in studying the feasibility of this technology by means of simulation.Tel: +46-704469795 Email: osman@ftw.at,amos04@student.bth.se, ammarmao@gmail.com
39
Gombachika, Harry Sam Harrison. "Mobile telecommunication CDMA power control for S-UMTS." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/842850/.
Full textAbstract:
Since under the UMTS framework, the development of S-UMTS follows that of T-UMTS with the ultimate aim of achieving close integration between S-UMTS and T-UMTS air-interface designs, closed-loop transmit power control (TPC) remains a physical-layer procedure option for enhancing the performance of S-UMTS. In S-UMTS, however, closed-loop TPC should be modified to take into account large TPC command delays due to propagation. In this thesis, we study strength-based closed-loop TPC schemes for S-UMTS in order to develop TPC schemes that mitigate the effects of TPC command delays due to propagation. The study focuses on link-level analysis of the SW-CDMA based air-interface for the S-UMTS. Firstly, a mathematical model describing the dynamic behaviour of the closed-loop TPC has been developed as a stochastic difference equation, where the effects of TPC command delays in the presence of random disturbance are modelled as a random walk process, with a probability density function (pdf) of the TPC error process as its solution. The pdf is obtained by solving a corresponding Fokker-Planck equation whose derivate moments are obtained via statistical linearisation. The results show that although it is widely accepted that the TPC error process is lognormally distributed, the nonlinearity due to the fixed TPC step-size may flatten the pdf when the TPC delays and step-size are large. Secondly, predictive TPC schemes that mitigate the effects of delays and adaptive techniques that improve upon the performance offered by standard algorithms have been proposed and evaluated through Monte-Carlo simulations. In particular, a simple LMS algorithm has been chosen as an appropriate tracking algorithm for the predictive TPC schemes in S-UMTS, and in order to improve upon the performance offered by the standard LMS algorithm, a filter-shaped LMS algorithm for predictive TPC has been proposed for S-UMTS. Furthermore, the simulation results have shown that step-size adaptation, when complemented with power prediction, significantly improves the performance of the closed-loop TPC schemes even in the presence of TPC command delays. Finally, numerical results have shown that the accuracy of TPC has significant influence on the capacity. For example, a modest improvement in the standard deviation of the TPC error from 1.5 dB to 1.0 dB may yield a capacity improvement from 21 to 32 users per spotbeam: a relative gain of approximately 50%. Therefore, closed-loop TPC remains an important radio resource management procedure for mitigating slow-fading due to shadowing in S-UMTS, power prediction mitigates the effects of TPC command delays, and more accurate TPC schemes are necessary to realise high capacity S-UMTS networks.
40
Werner, Marc Walter. "Maßnahmen zur Qualitäts- und Kapazitätssteigerung in UMTS-Mobilfunknetzen /." Aachen : Mainz, 2006. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=014903973&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full text
41
Knoche, Klaus [Verfasser]. "Empfänger-Strukturen für die UMTS-Abwärtsstrecke / Klaus Knoche." Aachen : Shaker, 2009. http://d-nb.info/1156518180/34.
Full text
42
Ahn, Dae-Young. "Interference management and code planning in WCDMA UMTS." Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252354.
Full text
43
Hadef, Mahmoud. "Adaptive equalisation for downlink UMTS terrestrial radio access." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438723.
Full text
44
VALE, EDUARDO RODRIGUES. "TECHNIQUES FOR VOICE TRANSMISSION IMPROVEMENT IN UMTS SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8933@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROA partir da necessidade do transporte de informação multimídia, foram desenvolvidos os Sistemas Celulares de Terceira Geração, ainda em fase de padronização, cujo candidato mais promissor é o UMTS (Universal Mobile Telecommunications System). De forma consonante com a tendência mundial de utilização crescente da tecnologia IP (Internet Protocol) nas redes fixas, o UMTS veio a incorporar este protocolo, que apresenta uma maior flexibilidade para a introdução de novos serviços. Assim, na arquitetura do UMTS existem atualmente dois modos de transmissão, a Comutação de Circuitos e a Comutação de Pacotes. Esta Tese de Doutorado descreve, inicialmente, os processos de estabelecimento de chamadas de voz no UMTS, tanto na modalidade de Comutação de Circuitos como na de Comutação de Pacotes. Em seguida, procura fazer uma avaliação comparativa da eficiência na execução de chamadas de voz nestas duas modalidades, com ênfase de aplicação no sentido uplink de transmissão. Neste processo, são desenvolvidas várias formas de otimização de desempenho da transmissão na interface aérea do UMTS, em particular na Comutação de Pacotes, visando tornar este modo de transmissão competitivo com o modo de Comutação de Circuitos em termos de eficiência na transmissão de voz. Embora o tratamento aqui apresentado se refira ao UMTS-FDD (UMTS Frequency Division Duplex), as técnicas aqui desenvolvidas também encontram aplicação em outros Sistemas Celulares de Terceira Geração congêneres, tal como o CDMA 2000.
With the advent of multimedia traffic, Third Generation mobile systems were introduced, with the UMTS as the most promissor candidate. In consonance with the global trend of utilization of the IP technology in fixed networks, the UMTS developers decided to incorporate this protocol, which presents more facilities for the introduction of new services. Therefore, the UMTS architecture has two transmission modes: Circuit Switching and Packet Switching Modes. This Doctoral Dissertation initially describes the call setup processes (call flows) for those transmission modes. It follows a comparative evaluation of the efficiency aspect related to calls executed in both modes, considering the case of uplink transmission. In this process, several optimization techniques are introduced, aiming at the improvement of energy consumption in the air interface. The final objetive is to turn the Packet Switching Mode competitive with the Circuit Switching Mode, relative to the energy consumed for the transmission of voice calls. Though the treatment here presented refers to the UMTS-FDD technology, all the results are equally applicable to other similar systems, like the CDMA- 2000.
45
Gleissner, Filip. "Koexistence mobilních komunikačních systémů GSM-EDGE a UMTS." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233470.
Full textAbstract:
The dissertation thesis deals with the investigation of the coexistence of GSM–EDGE and UMTS systems with focus on the physical layer of the systems. The aim is to provide a set of recommendations for practical cooperation while the systems operate in both the separated and the common radio bands. A detailed description of signal processing of both the systems on the physical layer is presented. On the basis of this description, models of both systems were created and implemented in the MATLAB environment. The simulations are focused on the physical layer quality parameters, especially the bit error ratio evaluation for various ratios of useful signal power to noise power during the transmission over the radio channel. Simulation is also used to examine the quality of received useful signal while it is interfered by signals from the same and adjacent channels. The purpose is to determine the isolation between these adjacent channels, when the bit error ratio of the useful signal does not exceed a certain reference value. The simulation results are subsequently subjected to comparison with the results of the experimental measurements in laboratory conditions. Before the measurements are carried out, a study of possible interference types is performed. Consequently, the crucial parameters of the measuring equipment used are verified. From the results of simulations and measurements, the proposal of a minimum and recommended carrier separation between both the systems is presented in order to efficiently utilize the assigned frequency spectrum. Furthermore, for the cooperation in both the separated and the common radio bands, the necessary precautions are given for reaching the required isolation and thereby inter-system interference minimization.
46
Almeida, Carlos Filipe Pereira de. "Acesso rádio UMTS, WLAN e WIMAX sobre fibra." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2005.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesO presente trabalho tem por objectivo o estudo e implementação de uma rede óptica passiva para a transmissão de sinais rádio sobre fibra. Para tal, são estudados e analisados diversos componentes optoelectrónicos que constituem uma rede óptica passiva, tendo em vista a optimização e desenvolvimento da mesma. Por forma a definir os limites, bem como desenvolver conhecimentos sobre os processos que limitam ondas de rádio em fibra, foram realizadas simulações computacionais em redes óptica passivas com transmissão de sinais 3G-UMTS, objectivando estudar possibilidades de acesso múltiplo, bem como os efeitos da alteração de determinadas propriedades dos dispositivos ópticos. Para demonstrar os processos limitativos da propagação, laboratorialmente foram implementadas duas topologias de redes ópticas passivas recorrendo a amplificadores ópticos e lasers de baixo custo, para estudar a transmissão de multi-formatos de sinais rádio sobre fibra. A primeira consiste na transmissão de um canal que consiste na modulação directa de um laser com o sinal rádio que pode ser 3G-UMTS, WLAN ou WiMAX. A segunda inclui, para além do cenário apresentado, um canal extra modulado em amplitude num cenário de multiplexagem no comprimento de onda. ABSTRACT: The present work intends to study and implement a passive optical network for the transmission of radio signals over optical fiber. For this intent, several optoelectronic devices used in passive optical networks were studied and analyzed in order to optimize the developed network. A passive optical network for the transmission of 3G-UMTS signals was simulated and the effect of multiple access and other optical factors were studied and analyzed. In the laboratory were implemented two different topologies for passive optical networks using low cost optical amplifiers and lasers in multi-format multiwavelength radio over fiber signals. The first consider the transmission of a single channel consisting of directly modulating the laser with a radio signal that can be UMTS, WLAN or WiMAX, and the second includes an extra channel with amplitude modulated signals in a wavelength division multiplexing scenario.
47
Pinho, Pedro Nuno Santos. "Plataforma de simulação para sistemas UMTS TDD UL." Master's thesis, Universidade de Aveiro, 2003. http://hdl.handle.net/10773/21760.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesEste trabalho descreve a arquitectura e o desenvolvimento de uma plataforma de avaliação de esquemas de processamento de sinal avançadas para a transmissão ascendente do modo TDD do “Universal Mobile Telecommunications System” (UMTS). A plataforma de simulação é baseada no pacote de simulação comercial COSSAP e abrange a camada física do “UMTS Terrestrial Radio Access” (UTRA), a partir / depois da descodificação / codificação do sinal, como especificada pelo 3GPP. Começa por dar uma perspectiva histórica da evolução das comunicações móveis, seguida de uma descrição resumida dos diferentes esquemas de acesso e de uma descrição mais pormenorizada do DS-CDMA, da aplicação de técnicas de antenas inteligentes e dos modelos de canal móvel de propagação. Depois é descrito o sistema UMTS e a arquitectura da plataforma de simulação. Termina apresentando alguns resultados numéricos que validam a plataforma desenvolvida e mostram a eficácia do receptor avançado S-T RAKE proposto, face ao receptor convencional do DS-CDMA (RAKE), como um meio de aumentar a capacidade do sistema UMTS.
This work describes the architecture and development of link level evaluation platform intended to evaluate advanced signal processing schemes for the Universal Mobile Telecommunications System (UMTS), Time Division Duplex (TDD), Up Link (UL) mode. The simulation platform is based on the COSSAP commercial simulation package and comprises the physical layer of the UTRA as specified by the 3GPP.It starts giving an historical overview of the evolution of the mobile communications, followed by a short description of the different access schemes and a detailed description about: the DS-CDMA scheme; the application of smart antennas; and the channel models for the air interface of the mobile networks. Then it is described the UMTS system and the architecture of the simulation platform. Finally some numerical results are presented that validates the developed platform and shows the effectiveness of the S-T RAKE advanced receiver versus the conventional DS-CDMA receiver (RAKE), as a means to enhance the capacity of the UMTS.
48
Krishna, Emir. "Security issues on m-Commerce over 3G/UMTS /." Leeds, 2001. http://www.leeds.ac.uk/library/counter2/compstmsc/20002001/krishna.doc.
Full text
49
Bednárik, Ján. "Modelování řízeného využití síťových zdrojů v sítích UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218142.
Full textAbstract:
The main aim of my master thesis was to get acquainted with the implementation of quality-of-service support methods in UMTS 3G mobile network and the evaluation of these methods in a simulation environment with main interest in the characteristic features of the traffic classes. The impact of the QoS methods available on different service types were verified in the OPNET Modeler simulation environment. I examined mainly the potentials of the model to support the required quality parameters for the connections. The models of typical network applications, available in real UMTS networks, together with two examples of mobile networks, operating voice and video services in combination with standard data services, were defined in this simulation environment. My work also contains the detailed description of configuration parameters fundamental for correct behavior of the simulation models. The simulation also shows the case, when the transport service is rejected due to the lack of network resources. The key parameters of the model are also described and their effect on the service quality with and without QoS control are compared in separate scenarios. Finally, I investigated the effect of mobility of the end stations on the communication process, especially on the duration of a file transmission.
50
Predajňa, Martin. "Lokalizátor interferencí pro kmitočtová pásma EGSM a UMTS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219108.
Full textAbstract:
Diploma thesis describes direction finding principles for passive localization of emitting source. Direction finding system with one rotating antenna was chosen with triangulation calculation of emitter position. Input parameters are position of measurement point and direction of maximum signal receiving level. A suitable digital compass module and GPS receiver module for this measurement was chosen. For this purpose was created a graphic user interface, which allow user to communicate with external devices and control spectrum analyzer. Results of measurements are displayed at map, together with area of possible positions of transmitter. Receiving Yagi antenna is placed on rotator and whole system is placed on roof of car. Whole system was construct and results of measurement are discuss here.