SIMULATION METHODOLOGY FOR ASSESSING MXRAN ARCHITECTURE PERFORMANCE ANJA WIEDEMANN PETER SCHEFCZIK GEORGIOS NIKOLAIDIS University of Essen Lucent Technologies University of Athens Institute for Experimental Mathematics Wireless Advanced Technology Lab Communication Networks Laboratory Ellernstr. 29 Thurn-und-Taxis-Strasse 10 Panepistimiopolis, Ilisia D-45326 Essen, Germany D-90411 Nuremberg, Germany 157 84 Athens, Greece Phone: +49 201 183-7635 Phone: +49 911 526-4604 Phone: +30 2 10 727 5654 Fax: +49 201 183-7673 Fax: +49 911 526-3183 Fax: +30 2 10- 727 5601 Email: wiedem@exp-math.uni-essen.de Email: pschefczik@lucent.com Email: nikolaid@di.uoa.gr Abstract 1 : Product life cycles in communications and other technology related industries are getting shorter and shorter. Consequently the performance of such systems must be evaluated early in the architecture design stage. In the wireless networks area new radio access technologies are applied and form a multistandard radio access network (MxRAN) which denotes an evolution of the current UMTS (Universal Mobile Telecommunications System) architecture defined by standards bodies. The MxRAN is a main part of the IPonAir [IPonAir homepage] project. For this project several network architecture options and protocol stacks must be assessed. This makes the availability of an easy to use performance evaluation tool indispensable. In this paper the requirements and the modeling concept of a flexible signaling performance model are depicted. Thereby a use case approach starting with a description in Message Sequence Charts (MSCs) is applied. This set of MSCs is then converted automatically to a generic model that can be executed in an event driven environment. keywords: Network Performance Models, Queueing Systems 1 The research reported in this paper has been partly conducted within the IPonAir program funded by the German Ministry of Education and Research (BMBF) under grant 01BU161. The responsibility for contents of this publication is with the authors. 1. INTRODUCTION In the IPonAir project a new flexible radio access network (RAN) architecture supporting existing and future IP-based protocols is conceived. Starting from the UMTS Release 5 (R5) RAN architecture new architecture options of the above mentioned type are evolved. Several different solutions must be compared to derive an optimal architecture with respect to protocol processing cost and signaling delay. Therefore a performance assessment in an early stage of the software design is needed to detect the most advantageous architectures and avoid capital investment in technologies which are not efficient. This is why a flexible signaling performance assessment methodology for decision support is provided and implemented in a tool chain. Thus the methodology can be applied easily for the comparison of different MxRAN architectures. The paper is organized as follows. First the requirements for the envisaged performance tool are identified. Then after a short overview on UMTS R5 the main scenarios (use cases) of the MxRAN control plane are listed. MSCs [SDL Forum 2001] are used for the specification of the use cases. The MSCs are annotated with additional processing related information. From the set of MSCs a table related representation is derived automatically. This representation of the use cases is transferred into an event driven simulation tool. Predefined generic modules are used in the network nodes of the event driven system. The modeling concept and the node internal generic modules applied are described. Then the realization within an OPNET event driven environment is explained by means of two architecture examples. The paper closes with a summary of the simulation methodology and some remarks concerning the future development and implementation of this simulation methodology. 2. REQUIREMENTS In this paragraph the requirements that have to be met by the envisaged simulation methodology are described. Proceedings 17th European Simulation Multiconference (c) SCS Europe BVBA, 2003 ISBN 3-936150-25-7