Zugl.: München, Techn. Univ., Diss.

High Speed Downlink Packet Access (HSDPA) is the extension to the Universal Mobile Telecommunication System (UMTS). HSDPA allows for higher data rates due to new adaptive Modulation and Coding (AMC) techniques, Hybrid Automatic Repeat reQuest (H-ARQ) and fast scheduling algorithm. One of the key features of HSDPA technology is to handle UMTS traffic classes with different Quality of Service (QoS) requirements. In order to provide QoS several scheduling algorithms, QoS control constraints, and different other schemes have been proposed in literature. In the thesis, a simple matlab based model for HSDPA is presented in order to simulate various algorithms. The QoS controls in terms of guaranteed bit rate (GBR) have been implemented by means of barrier functions which perform barrier around the feasible region. The results illustrate the trade-off between the cell throughput and the minimum guaranteed bit rate. Traffic classes are prioritized by means of QoS parameters. The priority is given to RT traffic streams over interactive services. Real-Time (RT) algorithms have been simulated to prioritize traffic classes based on delays. / QoS is the ability to provide resources and prioritize different applications. As mentioned before, the 3GPP standard defines four categories of service (Conversation, streaming, interactive and background) for UMTS. Strategies in traffic management, priority GBR allowances and bandwidth are important strategies for traffic differentiation and quality of service (QoS). Providing QoS over HSDPA is one of the challenging tasks for researchers. The significant results and findings of our thesis are as follows • In this thesis various algorithms were implemented with their duties barrier to provide guarantees of quality, in terms of speed guaranteed (GBR). The emphasis was to ensure the flow and priority categories of traffic. First the performance of algorithms were studied alone and then along with the barrier functions. It is concluded that barrier functions play an important role by means of providing QoS guarantee in HSDPA, considering channel conditions. Traffic classes were prioritized on QoS parameters defined for barrier functions. It was found that minimum bit rates were maintained by barrier functions but the cell throughput decreases with their barrier functions depending upon QoS parameters. The streaming aware scheduler has been evaluated by means of simulations in mixed scenarios and it is concluded that this algorithm protects streaming QoS in high overload conditions. It is therefore concluded that barrier functions and streaming aware schedulers are the best option for QoS control. These schedulers are very simple and consider diversity gains as well.

Dans la première partie de la thèse, on considère des méthodes d'estimation des canaux utilisateurs dédiés en liaison descendante. Ces méthodes sont particulièrement avantageuses dans un contexte de transmission à formation de faisceaux. Elles ne supposent aucune connaissance a priori des retards des signaux reçus ainsi que les paramètres de formation des faisceaux; exploitent la totalité des séquences pilotes transmises ainsi que la dynamique structurée du canal.Dans la seconde partie, on commence par considérer un schéma d'égalisation au niveau chip et dite HDD-NLMS. Ce schéma utilise l'estimation de la précédente séquence chip comme réponse cible pour l'adaptation de l'égaliseur. Dans la suite propose les égalisateurs niveau symbole HSDPA N-Griffith et HDD-NLMS qui permettent une vitesse d'adaptation 16 fois plus élevée que dans le cas de l'utilisation des symboles PCPICH. Les solutions spécifiques HSDPA ont une complexité raisonnable et offrent des performances proches aux Max-SINR dans un environnement réel.Dans la dernière partie, nous évaluons l'avantage des égalisateurs au niveau chip par rapport au récepteur Rake conventionnel ainsi que l'avantage d'une décision hard par rapport à l'utilisation d'une contre réaction linéaire dans le contexte d'un récepteur avec élimination itérative parallèle des interférences. Cette contre réaction sera déduite d'un développement polynomial de l'inverse de la matrice de covariance en amont du premier étage d'égalisation. Etant donné que les égalisateurs à chaque étage sont différents, nous utilisons les résultats d'analyse des étages précédents afin de pouvoir estimer les paramètres de l'égalisateur à un étage donné.

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

Diss. Univ. Linz, 2008.

Zugl.: Bochum, Univ., Diss., 2008

No description available.

L'augmentation de l'utilisation de l'Internet et des services de données motive l'évolution des réseaux cellulaires de troisième. Dans ce contexte, HSDPA (High Speed Downlink Packet Access) a été développé dans les releases 5 et 6 au sein de 3GPP pour poursuivre l'évolution du mode "paquet" de l'UMTS. Ce système utilise de nouvelles technologies telles que le Hybrid-ARQ (Automatic Repeat Request), la modulation adaptative et l'ordonnancement rapide (fast Scheduling) pour permettre de véhiculer des débits plus élevés sur l'interface radio et d'augmenter la capacité. Cette thèse se focalise sur l'analyse et la modélisation des interactions entre la couche MAC-hs de HSDPA et les autres couches (physique, transport). L'objectif est de trouver la configuration optimale de cette entité MAC-hs afin de réduire les interactions "négatives" entre-couches et optimiser les performances de HSDPA. Par conséquent, cette thèse fournit des études et des modélisations analytiques couvrant les aspects suivants: -Analyse et modélisation de l'impact du canal radio (shadowing, fast fading) sur les performances du système HSDPA dans le cas où plusieurs "schedulers" sont utilisés -Analyse et modélisation de l'effect des services "Circuit" de l'UMTS R99 sur les performances de HSDPA. -Modélisation de l'interaction entre le protocole TCP et l'entité MAC-hs. Une nouvelle stratégie d'ordonnancement est proposée afin d'améliorer les performances du système -Charactérisation de l'interaction entre MAc-hs et les services streaming. Une nouveau "scheduler" est proposé afin de garantir les contraintes sévères de QoS des services streaming sans trop perdre de capacité cellulaire.

High Speed Downlink Packet Access (HSDPA) is a cellular system that was standardized by the 3rd Generation Partnership Project (3GPP). HSDPA can support data rates of up to 14.4 Mbps through the use of a shared channel. Due to its high transmission rates, the highly popular multimedia applications are converging over this network. Moreover, as the shared channel is assigned to a single user in a given time interval, the scheduling decision is considered as a crucial one. Conventional HSDPA scheduling schemes utilize the fluctuations in channel condition to maximize system throughput by selecting users with relatively good radio conditions. However, this raises the issue of fairness as users with relatively poor channel conditions might not be served and consequently may suffer from starvation. Furthermore, Real-Time (RT) applications have strict delay constraints and require that packets are transmitted within a certain delay threshold. In this thesis, a Delay Based Scheduler (DBS) is proposed for HSDPA which aims at minimizing the average queuing delay at the packet scheduler without compromising system throughput and fairness. In addition, the scheme can balance the tradeoff between throughput maximization and the minimization of queuing delay through the attunement of a parameter, thus allowing the service provider to choose between these two metrics. The DBS maintains the delay constraints of RT applications by defining delay thresholds for each traffic class and dropping packets that exceed their delay limit. The DBS accommodates Quality of Service (QoS) prioritization by defining and utilizing desired QoS parameters in the scheduling assignment. Finally, it was mathematically shown that the DBS can converge to a Non-Real-Time (NRT) scheme known as the Max CIR algorithm, allowing the scheduler to support RT and NRT applications simultaneously. The performance of the DBS was evaluated and compared to other well known schemes. It was found that the DBS can minimize the aggregate queuing delay of the system and maintain similar throughput and fairness. / Thesis (Master, Computing) -- Queen's University, 2007-08-15 16:12:36.22

The topic of presented thesis is the subject of mobile Internet connectivity in the Czech Republic. The text is divided into two main parts. The first theoretical part is focused on an individual description of the technologies (GSM, GPRS, EDGE, UMTS and HSDPA) which are being offered in the Czech Republic by the operators. The greatest emphasis is put on a description of UMTS and HSDPA. The second part is practical; it describes the offers of each respective Czech operator focusing on the third-generation network or particularly the network operator with the highest connection speed. The thesis compares current offers against those in the year 2006. The next practical part is aimed at creating a methodology for testing mobile connections and its applications for UMTS and CDMA operator's tariffs at T-Mobile and Telefónica O2. The contribution of this work is to provide a comprehensive picture of a mobile Internet connection in the means of technological background and practical applications.