Comparison of Speed-up Techniques for Simulation

Due to increased complexity and extreme quality of service requirements, traditional means for performance evaluation of telecom networks do not always suffice. The most flexible approach has been, and still is, simulation, which is the main focus of this paper. However, severe problems regarding efficiency exist, e.g. evaluation of ATM cell loss rate in range of <10-9 which is very computer intensive and hardly feasible within reasonable time with direct simulation. This calls for new and more efficient simulation techniques. A short overview of some speed-up approaches is given. This paper compare three of the most promising techniques within the rare event provoking approach; importance sampling, RESTART and transition splitting. They have all demonstrated significant speed-ups over direct simulation. An experiment is carried out by the three techniques on the same system example, and the comparison measure takes into account both the variability in the estimates and the CPU time consumption.