| Modeling of External and Internal Impact Factors on the Performance of Wireless Local Area Networks As in tethered local networks (LANs), communication protocols (on different protocol layers) and traffic load have a significant impact on the performance of wireless LANs. Additionally, the wireless channel - especially in the context of mobility of the stations - heavily affects the design and performance of WLANs. This project merges these external and internal impact factors into an integrated simulation model. Key submodels encompass Markovian models for autocorrelated traffic generation and autocorrelated packet losses as well as detailed non-Markovian protocol models (IEEE 802.11, TCP/IP) and random waypoint mobility models. The developed
models can be validated by measurements with our software
monitor with high-resolution timestamping. Similarly,
measurements for lowly loaded and traffic-controlled systems
serve to determine model parameters (input modeling).
Model building is based on UML-statecharts extended with
timing (an implementation of real-time UML) as provided
by the commercial tool AnyLogic (by XJ technologies). This
tool also allows for discrete-continuous (hybrid)
simulation (as required for mobility modeling). The
measurement infrastructure has been successfully applied
in a web cluster project and been adapted to the
WLAN environment. A dedicated graphical user interface
provides access to the netfilter framework of Linux
and thus a flexible data collection. Several student
workers participated in model building and the implementation of the software monitor leading to various student theses. | Projektleitung:
Prof. Dr.-Ing. Reinhard German, Dr.-Ing. Armin Heindl
Beteiligte:
Prof. Dr.-Ing. Günter Hommel, Dr.-Ing. Kai-Steffen Jens Hielscher
Stichwörter:
WLANs; modeling; measurements; simulation; RT-UML
Laufzeit: 1.8.2000 - 31.3.2005
Förderer:
Deutsche Forschungsgemeinschaft
| | Publikationen |
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| Heindl, Armin: Inverse Characterization of Hyperexponential MAP(2)s. In: Al-Begain, Khalid ; Bolch (Hrsg.) : 11th Int. Conf. on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2004 Magdeburg, Germany 13-16 June 2004). 2004, S. 183-189. | | Resch, Christian ; Heindl, Armin ; Hielscher, Kai-Steffen Jens ; German, Reinhard: Measurement-based modeling of end-to-end delays in WLANs with ns-2. In: Hülsemann, Frank ; Kowarschik, Markus ; Rüde, Ulrich (Hrsg.) : Proc. 18th Symposium on Simulation Techniques (ASIM) (ASIM Erlangen, Germany September 2005). 2005, S. 254-259. |
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