A UMTS DL DCH Error Model Based on Measurements in Live Networks

In UMTS system level simulations DCH (Dedicated Channel) error models are used to represent the characteristics of lower layers in order to save simulation time. Usually DCH BLER (Block Error Ratio) statistics are taken from link level simulations or only certain fixed values for DCH BLER are used for system level simulations. In this paper we present measurements of UMTS DL(Down Link) DCH error characteristics for 360kbit/s UDP data traffic in different mobility scenarios for three different UMTS networks in Vienna, Austria. We show in particular that the DL DCH error characteristics do not vary much when low or high user mobility is given. Furthermore, performance differences in BLER statistics of fixed bearer vs. dynamic bearer switching are presented. Following the obtained statistics we develop a model for the UMTS DCH and we show that it is capable of properly describing the characteristics of the wireless channel.