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

In UMTS system level simulations DCH BLER models are used to represent the characteristics of lower layers in order to save simulation time. Usually DCH BLER 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 DCH BLER for 360kbit/s UDP data traffic (372kbit/s incl. UDP/IP overhead) in different mobility scenarios for three different UMTS networks in Vienna, Austria. We show in particular that the DL DCH BLER statistics do not vary much when low or high user mobility is given. Furthermore, performance differences in DL DCH 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.