Simulation of Throughput in UMTS Networks with Different Spreading Factors

We design and implement a local session admission control (SAC) algorithm for third-generation wireless networks which allows for the simulation of network throughput for different spreading factors and various mobility scenarios. The design of the SAC algorithm uses global information; it incorporates the session arrival rates and the user mobilities across the network and guarantees the users´ quality of service as well as pre-specified blocking probabilities. On the other hand, its implementation in each cell uses local information; it only requires the number of sessions currently active in that cell. A global SAC algorithm is also implemented and used as a benchmark since it is inherently optimized and uses global information in making every session admission decision; it yields the best possible performance but has an intensive computational complexity. Using simulation, we determine the network throughput, and show that our optimized local SAC algorithm achieves almost the same performance as our global SAC algorithm at a fraction of the computational cost for pre-specified blocking probabilities and quality of service requirements and spreading factor values of 256, 64, 16, and 4.