Required network size for system simulations in UMTS FDD uplink

This paper investigates the minimum network size for system simulations in UMTS FDD uplink that is required to yield reliable results of system performance, e.g. system capacity for multi-service operation. The yardstick for answering this question are the probability distributions of the interference at the base station as well as in the individual cells. These are found by studying various network configurations with a Monte Carlo simulation approach that keeps simulation time low. Published link-level results of required E_b /(N₀+I₀) serve as input to the simulator that handles multi-service scenarios with both speech and data users with different data rates of up to 384 kbit/s. Soft handover (SHO), transmit power control (TPC), variable antenna pattern at the BS and variable user distributions are included. A 19-site network turns out to be necessary and sufficient for single-site investigations. A 7-site network, though taking only 1/8 of simulation time, underestimates interference by several dB. Owing to its modular architecture, the simulator lends itself to any kind of system performance investigations in an FDD uplink