Les réseaux radiomobiles de 3ème generation, tel que l'UMTS (Universal Mobile Telecommunications System) ont été prévus, dès le début de leur conception, pour offrir un mode paquet aussi bien qu'un mode circuit. Pour fiabiliser les transmissions de données en mode paquet, il faut mettre en uvre des protocoles disposant de la technique ARQ (Automatic Repeat reQuest). L'objet de cette thèse est l'étude des protocoles ARQ qui peuvent être activés dans l'architecture protocolaire globale de l'UMTS. Cela nous amène à étudier les couches contenant les protocoles ou entités suivantes : RLC (Radio Link Control), TCP (Transmission Control Protocol) et MAC-hs (Medium Access Control-high speed). L'étude des nouvelles caractéristiques des protocoles ARQ de l'UMTS ainsi que la possibilité de leur enrichissement est effectuée. L'empilement des mécanismes ARQ présente des risques d'interactions dont certains sont analysés.

<p>The key idea of the new, shared high-capacity channel HSDPA, is to adapt the transmission rate to fast variations in the current radio conditions, thus enabling download peak data rates much higher than what WCDMA can offer today. This has induced a need for data that traverses the mobile network to be intermediately buffered in the Radio Base Station, RBS. A scheduling algorithm then basically selects the user with the most beneficial instantaneous radio conditions for access to the high-speed channel and transmission of its data over the air interface.</p><p>The purpose of this thesis is to design a flow control algorithm for the transmission of data packets between the network node directly above the RBS, the RNC, and the RBS. This flow control algorithm should keep the level of the buffers in the RBS on such a level that the air interface may be fully utilized. Yet it is not desirable with large buffers since e.g., this induces longer round-trip times as well as loss of all data in the buffers whenever the user moves to another cell and a handover is performed. Theoretical argumentations and simulations show that both of these requirements may be met, even though it is a balancing act.</p><p>Suggested is a control-theoretic framework in which the level in the RBS buffers are kept sufficiently large by taking into account predictions of future outflow over air and by using methods to compensate for outstanding data on the transport network. This makes it possible to keep the buffer levels stable and high enough to fully utilize the air interface. By using a more flexible adaptive control algorithm, it is shown possible to reach an even higher utilization of the air interface with the same or even lower buffering, which reduces the amount of data lost upon handovers. This loss is shown to be even more reduced by actively taking system messages about upcoming handover events into account as well.</p>

The key idea of the new, shared high-capacity channel HSDPA, is to adapt the transmission rate to fast variations in the current radio conditions, thus enabling download peak data rates much higher than what WCDMA can offer today. This has induced a need for data that traverses the mobile network to be intermediately buffered in the Radio Base Station, RBS. A scheduling algorithm then basically selects the user with the most beneficial instantaneous radio conditions for access to the high-speed channel and transmission of its data over the air interface. The purpose of this thesis is to design a flow control algorithm for the transmission of data packets between the network node directly above the RBS, the RNC, and the RBS. This flow control algorithm should keep the level of the buffers in the RBS on such a level that the air interface may be fully utilized. Yet it is not desirable with large buffers since e.g., this induces longer round-trip times as well as loss of all data in the buffers whenever the user moves to another cell and a handover is performed. Theoretical argumentations and simulations show that both of these requirements may be met, even though it is a balancing act. Suggested is a control-theoretic framework in which the level in the RBS buffers are kept sufficiently large by taking into account predictions of future outflow over air and by using methods to compensate for outstanding data on the transport network. This makes it possible to keep the buffer levels stable and high enough to fully utilize the air interface. By using a more flexible adaptive control algorithm, it is shown possible to reach an even higher utilization of the air interface with the same or even lower buffering, which reduces the amount of data lost upon handovers. This loss is shown to be even more reduced by actively taking system messages about upcoming handover events into account as well.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Nos Ãltimos anos, observa-se o surgimento e a rÃpida disseminaÃÃo do serviÃo VoIP, integrando-se ao mercado atual junto à telefonia convencional e Ãs redes celulares. Por ser uma alternativa tecnolÃgica que contribui para minimizar ustos, assiste-se a uma preferÃncia crescente por fazer fegar a voz atravÃs das redes IP. O HSDPA, como sistema celular, permite a transmissÃo de dados em alta velocidade, aumenta a largura de banda da rede e abre novas possibilidades de serviÃos multimÃdia, como o VoIP que utiliza a transmissÃo em banda larga para telefones mÃveis. Exige-se, porÃm, um considerÃvel esforÃo de anÃlise deste serviÃo, pois o atraso inerente a esse sistema à um desafio para a garantia de qualidade de voz. Estes fatos justificam, conseqÃentemente, um esforÃo de anÃlise que se detenha sobre a qualidade de voz no VoIP sobre o HSDPA. Para avaliar a qualidade de voz, neste estudo aplica-se o mÃtodo MOS, que faz corresponder valores numÃricos a categorias como medidas de qualidade e inteligibilidade da voz transmitida, obtendo-se esses dados de forma objetiva e subjetiva. O processo de avaliaÃÃo dividiu-se em etapas de acordo com cada metodologia, seguindo recomendaÃÃes tÃcnicas e atravÃs de simulaÃÃes computacionais dinÃmicas. Na avaliaÃÃo objetiva, utilizou-se o algoritmo PESQ para obtenÃÃo do conceito MOS, enquanto que na avaliaÃÃo subjetiva, arquivos de voz com certo percentual de erro foram colocados em um endereÃo na Internet para escuta e atribuiÃÃo de nota MOS, baseada na percepÃÃo do usuÃrio ouvinte. Os resultados mostraram que os dois mÃtodos de avaliaÃÃo obtiveram conceitos de qualidade satisfatÃrios, que o QoS nas simulaÃÃes à estÃvel e positivo, que uma boa qualidade para os arquivos de voz e a provÃvel satisfaÃÃo dos usuÃrios do serviÃo VoIP sobre o sistema celular HSDPA à garantida para uma taxa de 2% de FER. Finalmente, mostra-se que a metodologia objetiva garante a obtenÃÃo de notas MOS aproximadas da subjetiva, evitando o Ãrduo trabalho de fazerem-se ouvir diversos arquivos de voz por uma quantidade significativa de usuÃrios para ser vÃlida estatisticamente. / In recent years, we can observe the development and fast dissemination of VoIP services, being integrated by the present market, beside conventional telephony and cellular networks. For being a technological alternative that contributes to minimize costs, we see an increasing preference for voice transmission through IP networks. HSDPA, as a cellular system, allows high speed data transmission,increases the network width of band and creates new possibilities for multimedia services, as VoIP that transmits in wideband to mobile telephones. The delay inherent to this system, however, is a challenge for the need to assure good quality of voice transmissions, demanding a considerable effort of analysis of this service.These facts justify a study that focus on the quality of voice in VoIP over HSDPA.To evaluate the voice quality, in this study, we applied MOS method that makes numerical values correspond to categories like quality and intelligibility of transmitted voice, getting these data through objective and subjective methodologies. The evaluation process was divided in fases according to the characteristics of each methodology and to technical recommendations, and was done through dynamic computational simulations. For objective evaluation process,algorithm PESQ was employed to obtain MOS concepts, whereas, for subjective evaluation, voice files with a percentage of error have been placed in Internet for listening and for the attribution of MOS concepts based in the perception of the listener. The results of this research show that both evaluation methods got satisfactory concepts of quality, that QoS is steady and positive in the simulations, that a good quality for the voice files and the probable satisfaction of the users of the VoIP service on cellular system HSDPA is guaranteed for 2% FER rate. Finally, it shows that MOS concepts produced by objective methodology were close enough to those given by subjective evaluation to dispense with the arduous work of making diverse voice files to be heard and subjectively evaluated by a statisticaly valid amount of users.

[pt] Este trabalho é um estudo sobre um enlace do sistema HSDPA (High Speed Downlink Packet Access), um subsistema do padrão UMTS/WCDMA, desenvolvido para a transmissão de dados em alta velocidade no enlace de descida. Para atingir altas taxas de transmissão, é prevista a utilização, neste sistema, de diversas técnicas avançadas de processamento de sinais, entre elas a modulação adaptativa. O princípio desta técnica é escolher, para cada quadro de bits transmitido, a modulação mais adequada às condições do canal. Através de simulação, o desempenho da modulação adaptativa em enlaces HSDPA foi avaliado em [4], considerando um canal com desvanecimento plano. Estendendo este trabalho, foram introduzidos novos módulos no simulador, de forma a considerar um canal com multipercursos e a utilização de um receptor Rake. A estimação do canal, utilizada na adaptação, é implementada através da análise do sinal recebido e combinado no receptor Rake. O desempenho do enlace foi avaliado em presença de duplo percurso, para diversas situações, através da taxa de erro de pacote e da vazão obtida na transmissão, procurando-se investigar a influência de parâmetros do sistema e da interferência entre os dois percursos nesse desempenho. / [en] This work is a study about the performance of a HSDPA (High Speed Downlink Packet Access) which is a subsystem of UMTS/WCDMA designed for high-speed data transmission in the downlink. In order to achieve high bit rates, the use of advanced signal processing techniques, including adaptive modulation, is specified. This technique consists of choosing, for each transmitted frame, the most efficient modulation according to the channel condition. The performance of adaptive modulation in HSDPA links in a flat fading channel has been evaluated in [4] through simulation. In the present work, new simulation modules have been developed to consider multipath and a Rake receiver. The channel estimation used in the link adaptation is obtained from the received and combined signal at Rake receiver. The link level performance has been evaluated in a double path channel for different situations through packet error rate and throughput. The influence of system parameters and path interference on the performance has been investigated.

A key objective for 3G wireless networks, such as the Universal Mobile Telecommunication System (UMTS), is the explicit support for data communications for mobile users. Today, the dominant transport protocol in the Internet is the Transport Control Protocol (TCP). Since TCP was not tailored for wireless networks, there are some performance issues occurring when TCP traffic is transferred over a UMTS radio link. In this paper, the characteristics of TCP and UMTS are specified and the problems of TCP over UMTS dedicated channels (DCHs) are analyzed. The problem is high delays implying low utilization of allocated resources for small file transfers or due to packet losses. High Speed Downlink Packet Access (HSDPA)’s potential to solve the problem is studied. Since in HSDPA, High-Speed Downlink shared channel (HS-DSCH) is introduced as an alternative of DCH on downlink packet access, a model of HS-DSCH is built and simulations are performed in order to compare its TCP performance with DCH. The focus is on studying retransmission delay and Block Error Rate (BLER) targets. Some scheduling methods are also compared. The results indicate that HS-DSCH gives better TCP performance than a DCH, and that advanced scheduling methods gives similar result as round robin if there are packet losses. Moreover, a somewhat surprising result is found regarding fast retransmission and channel utilization for increasing BLER targets. / I denna rapport specificeras karaktäristiken för TCP and UMTS, och problemet med TCP över dedikerade UMTS kanaler analyseras. Problemet är höga fördröjningar som medför låg utnyttjande grad av allokerade resurser vid överföring av små filer eller vid paket förluster. High Speed Downlink Packet Access (HSDPA)’s potential att lösa problemet studeras. En modell av HS-DSCH konstrueras och simuleringar utförs för att jämföra dess TCP prestanda med DCH. Fokus är på att studera återsändningsfördröjning och BLER riktvärden. Några scheduleringsmetoder jämförs också. Resultatet indikerar att HS-DSCH ger bättre TCP prestanda än DCH, och att avancerad scheduleringsmetoder ger liknande resultat som round robin vid paket förluster. Dessutom har ett ganska överraskande resultat funnits kring snabb återsändning och kanal utnyttjande grad då BLER riktvärdet ökar.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / With the recent broadband upgrades to various cellular infrastructures and the myriad new emerging wireless broadband standards and services offered by carriers, it is often difficult to navigate this sea of technology. In deciding the best choice for broadband telemetry applications, one must look not only at the technology, but also at the economics, market timing, bandwidths, legacy issues, future expandability and coverage, security, protocols, and the requirements of the specific application. This paper reviews the technology roadmap of cellular providers keeping these issues in perspective as they apply to TCP/IP data for images, audio, video, and other broadband telemetry data using CDMA 1xRTT, EV-DO, and EV-DO Rev A systems as well as GSM GPRS/EDGE, UMTS/W-CDMA, HSDPA, and HSUPA networks. Lastly, issues seen by system integrators when using cellular channels for telemetry applications are examined, and a case is presented for overcoming many of these issues through the use of cellular routers.

<p>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. </p><p>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. </p><p>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.</p>

<p>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. </p><p>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. </p><p>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.</p>

<p>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. </p><p>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.</p>