Bøger i Advanced Studies Mobile Research Center Bremen serien

The key to a successful future mobile communication system lies in the design of its radio scheduler. One of the key challenges of the radio scheduler is how to provide the right balance between Quality of Service (QoS) guarantees and the overall system performance. Yasir Zaki proposes innovative solutions for the design of the Long Term Evolution (LTE) radio scheduler and presents several LTE radio scheduler analytical models that can be used as efficient tools for radio dimensioning. The author also introduces a novel wireless network virtualization framework and highlights the potential gains of using this framework for the future network operators. This framework enables the operators to share their resources and reduce their cost, thus achieving a better overall system performance and radio resource utilization.

Max Gath presents a multiagent system for the optimization of transport logistics in highly complex and dynamic domains. The described solution dynamically optimizes processes and provides a high flexibility, scalability, robustness, and adaptability to individual customer demands. The experimental evaluation points out the effectiveness and efficiency by using the example of commonly applied benchmarks as well as two case studies in groupage traffic and in courier, express, and parcel services with same-day deliveries. Both case studies were performed with leading transport companies in Germany. The results demonstrate that the multiagent-based solution satisfies domain-specific requirements and exploits high optimization potential in real-world processes. 

When joining Siemens in 2001, I also extended my research interest towards radio net work planning methodologies. This area of research brought together my personal interest in mobile communications and in the design of ef?cient algorithms and data structures. Between 2001 and 2003, I participated in the EU project Momentum, which was target ing the performance evaluation and optimization of UMTS radio networks. In this project my main focus was on Monte Carlo snapshot techniques, shortly after I broadened my research scope towards network optimization techniques. Both constitute the basis of this thesis. Later I got the chance to bring in the ideas and methods of my thesis into a Siemens internal planning and optimization tool, the development of which I guided over the last two years. First of all I would like to thank Professor Dr. Carmelita Görg for supervising this thesis, for her guidance, and her encouragement. I very much appreciate that she although I, as an external Ph. D. student, was not part of her department at the University of Bremen was always very open for discussions and provided me with a large amount of useful suggestions over the past years. I without a doubt greatly bene?ted from this, both in my scienti?c work and personally. I am also deeply grateful for the comments and suggestions by Professor Dr. Thomas Kürner, who is also the second examiner of this thesis.

Thomas Wagner untersucht die grundlegende Frage, welche raumlichen Informationen zur Navigation benotigt werden, wahrend aktuelle klassische Ansatze zur Navigation darauf fokussieren ein Maximum an Informationen zu verarbeiten. Der Autor zeigt formal wie auch in der Simulation, dass bei geeigneter Modellierung bereits reines egozentrisches Reihenfolgewissen (Ordnungsinformationen) ausreicht, um komplexe Navigationsleistungen robust zu vollbringen.

This book emerged out of research done during the period between 2004 and 2016 on the topic of mobile and wearable computing. The result is a comprehensive presentation of research findings covering different important aspects in the domain of wearable and pervasive computing for a better life.

Design and development of a cost-effective mobile broadband wireless access network is a key challenge for many mobile network operators. Overdimensioning or underdimensioning of the access network results in additional costs and a reduction of the customer satisfaction, respectively.   Thushara Weerawardane introduces new transport technologies and features for High Speed Packet Access (HSPA) and Long-Term Evolution (LTE) networks. He proposes novel adaptive flow control and enhanced congestion control algorithms and develops corresponding analytical models. These models are based on Markov chains and can be performed for faster analysis evaluation compared to long lasting detailed simulations. Both simulation and analytical models provide optimum network performance and reliable guaranteed quality of standard for the end users during congestion in the transport network. Further, the author investigates and analyzes the LTE transport network performance by introducing novel traffic differentiation models and buffer management techniques during intra-LTE handovers.

Bernd-Ludwig Wenning presents a context-based routing framework which can be applied to routing in different application domains. The routing framework includes the signaling as well as a decision system that is applied for route selection.

Xi Li presents innovative analytical models and algorithms for the dimensioning of the 3G UMTS Radio Access Network (RAN). The proposed analytical models allow efficient and accurate dimensioning for different evolutions of UMTS radio access technologies.

In recent years, originally static and single purpose Wireless Sensor Networks have moved towards applications that need support for mobility and multiple purposes. These heterogeneous applications and services demand for a framework which distributes and discovers the various services, so that other pieces of equipment can use them. Markus Becker studies, extends, analytically models, simulates and employs the so called Trickle algorithm in measurements in a Wireless Sensor Network test bed for the service distribution. The obtained results apply to the application of the Trickle algorithm at lower protocol layers, e.g. for routing, as well. Given application delay requirements, the author derives the realizable distances and number of nodes for two network topologies from the 95 percentiles obtained by simulation.

Eugen Lamers explains the principle of simulation speed-up in general and shortly demonstrates the technique RESTART for the simulation of rare events. He introduces the Short-Term Dynamic Simulation concept, developed for the planning of mobile radio networks.

The universalmobiletelecommunications system (UMTS) is a technical standard for a third generation (3G) telecommunication system. UMTS provides data rates more than three 1 times higher than its second generation (2G) predecessors. The increased speed en­ ables, for example, video calls, music downloads, or fast web surfing. The technology is already widely available. In 2007, a total of 166 commercial UMTS radio networks are operational in 66 countries covering all continents (UMTS Forum, 20°7), and there are already more than 100 million UMTS subscribers (3GToday. com, 2007; UMTS Forum, 2006). The market for mobile telecommunication is, however, increasingly competi­ tive, therefore operators need to invest effectively. In Western Europe, mobile phone penetration has reached 100 % in 2006 and the average revenue per customer is de­ clining (3G. co. uk, 2007). Besides spectrum license fees, the main cost driver is network infrastructure (Ellingeret al. , 2002). Radio network planning can cut operational and capital expenditure by up to 30 % (Dehghan, 2005). Good radio network planning is difficult for UMTS, because its radio interface is more complex than anything used at mass-market level before (Dehghan, 2005). Con­ nections are separated via codes; they share the same frequency band and are thus subject to interference. On each link, the system constantly regulates the amount of generated interference to a minimum via a power-control feedback loop.

Andreas Könsgen describes two major areas of spectrum management: the coordination of neighbouring networks with overlapping ranges by controlling different transmission parameters and the channel allocation by the base station inside a radio cell using a cross-layer approach. Theoretical analyses and simulations demonstrate the usage of these methods and show the QoS enhancements which can be achieved.

Frau Dr. Rügge hat es mit dieser Arbeit unternommen, das Spannungsfeld zwischen Tät- keiten in der Arbeitswelt jenseits des Büros und der dafür bisher gedachten mobilen Anw- dungen auszuloten. Untersuchungen auf diesem neuen Gebiet sind sehr dünn gesät und gehen kaum über Marketing-Studien für mobile Endgeräte mit ihren spezialisierten Anwendungen hinaus. Insofern ist diese Arbeit grundlegend, besonders da sie auf eine Perspektive abhebt, die einerseits sehr umfassend und daher anspruchsvoll ist, andererseits aber auch von einer weise aber leider erst zu spät in den üblichen Entwicklungsprozessen berücksichtigt wird. unter dieser Sicht besonders interessant, weil er trotz der dafür erforderlichen Breite der Untersuchung genügend tief auch die bestimmenden technischen Aspekte auslotet. Frau Rügge hat dieses Buch durch neun Thesen gegliedert, die für die Behandlung des Die Eigenschaften von Tätigkeiten, die Mobilität erfordern, sind maßgeblich für die Es wurde bisher zu stark technologiespezifisch agiert und zu weni Einzeltechnologien sind daher bald wieder vom Markt verschwunden. Hardware, Software und Organisation bild EntwicklerInnen immer wieder auf Entwurfskonflikte stoßen. ndenen Arbeitsprozesse ist ein weiteres Erfolgskriterium. eits von der für einen Einsatzbereich und andererseits aber vor allem von der Berücksichti Die Mensch-Maschine-Interaktion bestim Es bedarf neuer Methoden der Anford Tätigkeiten und Technologien. Selbst wenn manche dieser Thesen auch für klar, dass Frau Rügge ihrer Arbeit einen wesentlich breiteren multiperspektivischen F- schungsansatz zugrunde legt, der nicht nur Kritik an den aktuellen Technologien für mobile Tätigkeiten von ihrer Eignung her übt, sondern auch konstruktiv ermittelt, wie diese mobilen

Examines user interfaces for wearable computers and analyses the challenges imposed by the wearable computing paradigm through its dual-task character. This title introduces a software tool as well as the HotWire evaluation method to facilitate user interface development and evaluation.

Thomas Poetsch investigates the channel properties of cellular networks and analyzes the effects that cause inefficient performance of legacy congestion control protocols, such as TCP and its variants, on cellular networks.