El despliegue de las redes celulares 3G/3.5G plantea un reto a las estrategias de planificación y optimización radio tradicionales. A diferencia de los sistemas 2G FDMA, cobertura y capacidad están estrechamente ligadas y deben ser tratadas conjuntamente. Además, están presentes nuevos y más sofisticados algoritmos de gestión de recursos radio (RRM) así como una concepción de red más flexible, con múltiples parámetros interdependientes con ajuste no trivial. Un nuevo paradigma de planificación radio aparece y la red se optimiza mediante complejos algoritmos ya sea estática o dinámicamente. Esta tesis doctoral supone una contribución a la optimización de las redes de acceso radio en sistemas 3G/3.5G. Varios aspectos susceptibles de mejorar la planificación han sido investigados y nuevos métodos, directrices y estrategias de análisis se proponen con el objetivo final de mejorar el rendimiento del sistema. También se han diseñado y estudiado mecanismos dinámicos que se encuentran en la frontera difusa entre la planificación y la RRM. La 1ª parte de la tesis trata la configuración de las estaciones base. El impacto de las potencias piloto, inclinación de antenas y sus interacciones con parámetros de soft handover son investigados. Se hace énfasis en los efectos más allá de los conocidos y se derivan reglas para su ajuste. A partir de los resultados, se propone una estrategia para su Planificación Automática. El objetivo final es encontrar una combinación tal que el tráfico sea ecualizado de manera efectiva entre las celdas e incrementar la capacidad del sistema. La técnica se basa en la metaheurística Simulated Annealing y es capaz de mejorar el rendimiento global de la red, representado por una función de coste con información sobre el factor de carga y sujeta a otras condiciones de calidad. La importancia de los requisitos que impone el UL, a menudo olvidados en propuestas anteriores, también se ha incluido y estudiado analíticamente. La reconfiguración de las base no es el único medio para modificar la cobertura de las celdas, en este sentido el estudio se amplía mediante la introducción de repetidores, que permiten la generación de celdas distribuidas. En este caso la planificación es más compleja debido a la aparición de nuevos efectos que no se daban en las redes clásicas 2G FDMA. La mayoría de los trabajos que tratan con repetidores tienden a ignorarlos. Por ello, la investigación se centró en el modelado y cuantificación de su impacto así como en derivar directrices de planificación. Se ha obtenido analíticamente la nueva expresión que define la región de admisión y se concluye que existe un compromiso entre capacidad y cobertura, analizado tanto teóricamente como mediante simulación. Ciertos parámetros presentan un impacto importante y se han estudiado para obtener reglas prácticas de ajuste. La variación de cobertura en la celda padre antes y después de la instalación de repetidores también ha sido modelada. Posteriormente, se propone una nueva metodología para analizar estos despliegues, teniendo en cuenta de manera realista los retardos de propagación y el comportamiento del receptor Rake. Esto permite un análisis superior con respecto a enfoques tradicionales que, en determinadas circunstancias, tienden a ofrecer cifras erróneamente optimistas. La última parte de la tesis da un paso más en la Planificación Automática y se proponen y validan 2 mecanismos dinámicos que permiten a la red reaccionar y auto-optimizarse frente a cambios en las condiciones de tráfico. El primero, basado en conclusiones anteriores, persigue detectar si uno de los enlaces presenta problemas de capacidad y, en caso afirmativo, favorecerlo para retrasar los mecanismos de control de congestión. Por último, se introduce la tecnología HSDPA y, después de analizar los recursos que deben ser compartidos con versiones previas de UMTS, se concluye que es deseable un sistema para la gestión dinámica del árbol de códigos OVSF. Se propone y valida un mecanismo que maximiza el throughput de las celdas, garantizando al mismo tiempo criterios de bloqueo y dropping. / The deployment of 3G/3.5G cellular networks challenges traditional radio planning and optimization strategies. Unlike FDMA based 2G systems, coverage and capacity are tightly coupled and must be treated as a whole. Besides new and more sophisticated Radio Resource Management (RRM) algorithms are present along with a more flexible network with many interdependent parameters, whose joint adjustment is not trivial. A new radio planning paradigm appears in which the radio network is optimized by means of complex algorithms both in a static and a dynamic way. This Ph.D. thesis provides a contribution to the radio network optimization of 3G/3.5G networks. Several issues to improve radio network planning have been investigated and new methods, guidelines and strategies of analysis have been proposed with the final objective of enhancing the wireless access network performance. Dynamic mechanisms being in the blurred line between radio planning and RRM are also devised and studied. The first part of this dissertation deals with the configuration of Base Stations (BSs) the impact of pilot powers, downtilt of antennas and interactions thereof with Soft Handover parameters are investigated. Effects beyond well-known facts are outlined and new planning guidelines are derived. Given the results, an Automatic Planning strategy is devised to automate the configuration of these parameters and to find a combination such as traffic is effectively equalized among cells and a higher capacity is achieved. The technique is based on the Simulated Annealing metaheuristic and is able to improve the global performance of the network, represented by a cost function containing information on the load factor and subject to other quality constraints. The importance of uplink (UL) requirements, usually missed by existent proposals, has been also included and analytically addressed. Reconfiguring BSs is not the only means to modify cell shapes, in this sense the study is extended by introducing repeaters, which allow generating distributed coverage areas. This is the context of the second part of the thesis. New effects not present in FDMA based 2G systems imply that the radio planning process becomes more complex. Most existent papers dealing with repeaters in WCDMA networks, ignore these effects or claim their irrelevance. That is why the research work was focused in modeling them, quantifying their impact and deriving radio planning guidelines to enhance the final performance of the radio access network. The new expression for the feasibility condition has been analytically obtained showing a tradeoff between capacity and coverage. This has been analyzed both theoretically and by means of simulations and the adjustment of several parameters which have a significant impact is discussed to derive practical rules of thumb. Variation on the coverage of the donor cell before and after installing repeaters is also modeled. Subsequently, it is proposed a new methodology to analyze WCDMA networks with repeaters deployment, considering realistically path delays and the behavior of Rake receivers. This allows an enhanced analysis with respect to traditional approaches which, under certain circumstances, tend to provide erroneously optimistic metrics. The final part of the dissertation goes one step further in Automatic Planning and two dynamic mechanisms are proposed and validated so that the network can react and self tune in front of changes in traffic conditions. The first one follows some previous conclusions and aims at detecting if one of the links has capacity problems and if so, favors it to delay congestion control actions. Finally, HSDPA technology is introduced and, after analyzing the resources to be shared with a previous release of UMTS, it is concluded that a system that dynamically manages the OVSF code tree is desired. A mechanism aiming at maximizing cell throughput while guaranteeing blocking and dropping criteria is proposed and validated.

The increasing use of data services and the importance of IP basedservices in third generation mobile communication system (3G), requires the transmission from the cell phone to the base station, i.e. uplink, to manage high speed data rates. In the air interface for 3G in Europe, WCDMA, a concept for enhancing the transmission from the cell phone to the base station, called Enhanced Uplink, is being standardized. The overall goal is to provide high speed data access for the uplink. One of the requirements is that the enhanced uplink channels must be able to coexist with already existing WCDMA releases. For example, the enhanced uplink must not impact seriously on real time services, such as speech, carried on current WCDMA channels. The purpose of this work is to study how the quality, coverage and capacity of real time services carried on previous WCDMA releases is affected when introducing the Enhanced Uplink in a WCDMA network. The main focus of the study is thus to demonstrate the trade-off between voice and best effort performances. Theoretical assessments and simulations show that the Enhanced Uplink has many advantages over previous WCDMA releases. For example the Enhanced Uplink yields a larger system throughput for all voice loads. The noise rise, i.e. the ratio of total received power to the background noise power is being considered as the resource. It is shown that user traffic carried on the Enhanced Uplink is able to operate under a higher noise rise level as well as to get a higher throughput per noise rise. The resource is hence more efficiently utilized.

In the current era of telecommunication the usage of cellular network has increased rapidly. Number of different new services are introduced i.e. navigation, friend finder, internet browsing, nearby filling stations, shopping centers, traffic information and emergency services. Most of these services are location based and needs the information of particular area to provide the exact services. The addition of location based services in 3G network opens the new ways of using Mobile devices due to which cellular networks has faced number of challenges in providing better positioning accuracy which is the main requirement for location based services. To bear these challenges everyday new ways of finding the accurate position are introduced but most them required upgraded networks or highly equipped terminal. In this thesis the purpose is to find the potential in UMTS signaling data to estimate the position of the user equipment as accurate as possible using the legacy terminals. In this thesis SFN-SFN observed time difference is explored and used in Database Correlation Method (DCM) in network based positioning. This thesis is done by first analyzing the RSCP for the particular area to verify the conditions of FCC. The data is collected in real environment through test drive using TEMS investigation tool and the available measurement reports from the terminal are used to design and implement the DCM Algorithm. Two new approaches are introduced in this thesis SFN-SFN OTD and Hybrid. In Hybrid RSCP and SFN-SFN OTD are used together. In conclusion, the final results from the performed experiments show improvement in estimated position accuracy by Hybrid technique which is a new step in finding the position of user equipment by DCM.

This thesis studies the Message Queue Telemetry Transport protocol (MQTT) as an application layer protocol in geographical location sharing applications using third generation cellular communication (3G). The MQTT protocol is compared in terms of energy efficiency and amount of data generated with the Hypertext Transfer Protocol (HTTP), which is currently used in typical location sharing applications. In order to compare the communication energy efficiency of both protocols a location sharing application prototype was developed for the Android platform. The application allows the use of HTTP and MQTT and was used to perform a number of experiments. The evaluation experiments show that MQTT is a good candidate as a protocol for location sharing. At comparable bandwidth and energy expenses MQTT offers better quality of user experience, since the subscribers are notified at once when the location of clients of interest has changed. The MQTT protocol is more energy-efficient than the HTTP protocol when the number of other uses with whom the client shares location is low and the location updates are frequent. The experiments also indicate that MQTT protocol is more energy-efficient than HTTP protocol in idle state, when there are no location information updates due to inactivity of all the clients, for example, if they are stationary. This is because MQTT client does not spend energy to poll the server for information updates.

Power control is one of the technologies used to utilize the radio resources as efficient as possible in WCDMA. The transmission power is adjusted to transmit with the lowest power level possible while the required received signal quality is maintained. Since there are large variation in channel quality over time, the power has to be adjusted to compensate for these variations. During moments of bad channel conditions a high transmission power has to be used which will to a greater extent interfere with other users in the system. To solve this problem a concept called transmission timing was proposed. The basic idea is that the transmitter avoids data transmission during the short periods of bad channel conditions caused by fast fading. Higher bit rates can be used to compensate for this when the channel conditions are good. In this thesis the performance of transmission timing applied to uplink data transmissions is evaluated. This is accomplished through a theoretical analysis as well as simulations of a cellular system using transmission timing. Lowered transmission power is achieved and thus lowered interference is induced. Simulations showed that the transmission power can be lowered by up to 1.6 dB compared to ordinary continuous transmission with equal average data rate. These results are however strongly dependent on the used radio environment. It is also showed that transmission timing provides increased system stability in case of rapid changes in the load situation.

The interest for various multimedia services accessed via the Internet has been growing immensely along with the bandwidth available. A similar development has emerged in the 3G mobile network. The focus of this master thesis is on the speech/audio part of a 3G multimedia application. The purpose has been to implement a traffic generating tool that can measure QoS (Quality of Service) in 3G networks. The application is compliant to the 3G standards, i.e. it uses AMR (Adaptive Multi Rate), SIP (Session Initiation Protocol) and RTP (Real Time Transport Protocol). AMR is a speech compression algorithm with the special feature that it can compress speech into several different bitrates. SIP signalling is used so that different applications can agree on how to communicate. RTP carries the speech frames over the network, in order to provide features that are necessary for media/multimedia applications. Issues like perception of audio and QoS related parameters is also discussed, from the perspective of users and developers.

The Internet has mainly been interconnecting stationary computers by wired links, but an increasing number of mobile clients require wireless communication. One way to connect these clients is to use the Universal Mobile Telecommunication System, UMTS. UMTS is a third generation mobile system. A network can be seen as nodes interconnected by links. The functionality of the nodes can be described as a layered hierarchy. A reference model for this hierarchy was developed by OSI. In this model the second lowest layer is called data link layer. The data link layer is responsible for making the raw transmission appear error free to upper layers. The focus for this thesis is the data link layer in the UMTS. Compared to the data link layer in a wired scenario it contains more control and error correction mechanisms. These mechanisms use a lot of timers and triggers, which makes it very difficult to analyze them mathematically. Therefore simulation is the preferred method. For the simulations the network simulator version 2 was used. This is an open source discrete event simulator. It has a modularized wireless stack already implemented. This can not be used to simulate UMTS though. Some modules in this stack were replaced by a new implementation to make simulations on UMTS possible. Tests were performed on the new implementation and the results were what could be expected. The results were also consistent with previous research in the area.

The third generation, 3G, mobile telephone systems are designed for multimedia communication and will offer us similar services as in our stationary computers. This will involve large traffic loads, especially in the downlink direction, i.e. from base station to terminal. To improve the downlink capacity for packet data services a new concept is included in evolved 3G networks. The concept is called High Speed Data Packet Access, HSDPA, and provides peak bit rates of 14 Mbps. HSDPA uses a so-called best effort channel, i.e. it is developed for services that do not require guaranteed bit rates. The channel is divided in time between the users and a scheduling algorithm is used to allocate the channel among them. Streaming is a common technology for video transmission over the Internet and with 3G it is supposed to become popular also in our mobiles. Streaming generates lots of data traffic in the downlink direction and it would thus be satisfying to make use of the high bit rates HSDPA provides. The problem is that streaming requires reasonable stable bit rates, which is not guaranteed using HSDPA. The aim of this study is to modify the scheduling algorithms to prioritise streaming over web users and provide streaming Quality of Service, QoS. QoS is the ability to guarantee certain transmission characteristics. The results of the study show that it is hard to improve the streaming capacity by modifications of the scheduling. Of course, a consequence is that the web user throughput is decreased and to avoid this, new users have to be rejected by the admission control.The solution is to prioritise the streaming users both in the scheduling algorithm and in the admission control, i.e. when the system is nearly full new web users are rejected. By doing so the results are significantly improved.

In the standardized air interface for third generation mobile communication systems, WCDMA release 5, a concept called High Speed Downlink Packet Access (HSDPA) is introduced. HSDPA enables faster transmissions from base stations to mobile users by using a shared, high-capacity channel called the High-Speed Downlink Shared Channel (HS-DSCH) that is designed for best effort services. The HS-DSCH is developed for usage in the frequency band licensed for third generation communication systems. As the use of licensed frequency bands is costly it may be interesting to make use of the unlicensed frequency bands at 2.4 GHz and 5 GHz with higher interference and stricter regulations. Using HS- DSCH in unlicensed frequency bands would lead to smaller costs and a new kind of usage of the HS-DSCH. In order to transmit in unlicensed frequency bands, some requirements set up by the public authorities must be followed. This means that the maximum transmit power used by the HS-DSCH must be decreased and, on the 5 GHz frequency band, that features to avoid disturbing radar systems have to be implemented. The HS- DSCH has a bandwidth of 5 MHz. To use the available frequency spectra more efficiently, multiple carriers could be used. Wireless Local Area Networks (WLANs) are the most common way to transfer data in unlicensed frequency bands today. Assessments and simulations of WLAN and the HS-DSCH in unlicensed frequency bands show that WLAN can provide higher bitrates than the HS-DSCH for low loads. HS-DSCH can however provide a larger coverage per base station, and is more bandwidth effective than WLAN. Using a larger bandwidth is necessary for HS-DSCH to compete with WLAN, which uses a bandwidth approximately four times as large as the HS-DSCH bandwidth. The usage of the HS-DSCH in unlicensed frequency bands also has the advantage that the services provided by the third generation communication systems can be accessed easily.

Enhanced packet-data access is a trend in third generation mobile communication system. WCDMA Release 5 introduces HSDPA (High Speed Packet Data Access) with a brand new downlink transport channel HS-DSCH (High Speed Downlink Shared Channel) into 3GPP specification to provide greater capacity. HS-DSCH supports some new feature such as fast link adaptation, fast scheduling and fast HARQ (hybrid ARQ) so as to increase system performance. It efficiently improves power utilization, shortens retransmission time and increases system throughput. The focus for this thesis is implementation and simulation of HSDPA functionality with ns-2. There is some previous work has been done, such as EURANE. EURANE is an end to end extension which adds several HSDPA modules to ns-2. This paper addresses the analysis of HSDPA by simulating on HS-DSCH based on EURANE, and extends the power consumption on HS-DSCH.