Falk Dietrich

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Currently, 3GPP standardizes an evolved UTRAN (E-UTRAN) within the Release 8 Long Term Evolution (LTE) project. Targets include higher spectral efficiency, lower latency, higher peak data rate when compared to previous 3GPP air interfaces. The air interface of E-UTRAN is based on OFDMA and MIMO in downlink and on SCFDMA in uplink Main challenges for a(More)
With the increasing penetration of packet-switching network technologies that provide asynchronous network services, and the simultaneous necessity of accommodating synchronization-sensitive data types (i.e., voice, audio and video), the problem of keeping end-systems mutually synchronized is becoming critical and more complex than in traditional(More)
In this paper we present a method to perform run-time monitoring of distributed applications built on top of a distributed object oriented processing environment. For this, we instrument the code at the compilation time in order to send notiications to an Observer when relevant events occur in the system; the instrumentation is done in an automated manner,(More)
We survey formal methods as they are applied to the development of communication services. We report on industrial and academic projects, consider di erent communication architectures and work related to the feature interaction problem. Based on our survey and on extensive discussions with the industry, we investigate important industrial concerns and(More)
The concept of event-based behavioral abstraction (EBBA) is shown to facilitate the Design For Testability (DFT) if the set of events is well-chosen. We provide a prede ned set of events which, together with linear-time temporal logic, can be used for expressing behavioral properties in object-oriented distributed systems. This allows automizing several(More)
| Given a particular multimedia service, the problem is to show that the implemented service is behaving as expected. Middleware platforms do not only ooer the possibility to develop distributed multimedia services easier and faster but can also be used to facilitate the observation and testing process of such services. We concentrate on the problem of(More)
We present a framework for constructing formal models of object-oriented distributed systems and a property language to express behavioral constraints in such models. Most of the existing models have their origin in specific mathematical notations and/or concepts. In contrast, we have developed our model such that it accounts for a large set of phenomena(More)
In this work we address the problem of supporting the QoS requirements for appli cations while e ciently allocating the network resources We analyse this problem at the source node where the tra c pro le is negotiated with the network and the tra c is shaped according to the contract We advocate VBR renegotiation as an e cient mechanism to accommodate traf(More)
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