MoDySim — A parallel dynamical UMTS simulator

UMTS is a third generation mobile telecommunication system, which enables multi-service and multi-bit rate communication going beyond the possibilities of previous systems. The simulator MoDySirn models UMTS in great detail. Characteristics of UMTS, such as soft hand-over and the interdependency of load and capacity among neighboring cells are challenges for the parallelization of such a system. MoDySim is a dynamical simulator (in contrast to a snap-shot simulator)— that is, it simulates the behavior of the system over time taking into account movements and usage behavior of the users as well as the dynamics of the network control. The sizes of the systems to be investigated make it necessary to parallelize the programme in order to shorten its run time to a reasonable length. The chapter focuses on the parallelization aspects of MoDySim. The main problems to be dealt with in the parallelization are: the interference in UMTS is a long range effect. Interference couples large parts of the system, while one would like to exploit data locality of small sub-systems in a parallel programme. The effects of cell breathing and soft hand-over imply an absence of a natural (unique) home process for the mobile stations. And the power control implies (in principle) extensive communication between the processes.