Impact of mixed voice and data traffic on the UMTS-FDD performance

The provision of multimedia services to mobile users is one of the main goals of third generation (3G) systems. The traffic being transferred within 3G mobile networks will be composed by different information flows with various constraints on the required QoS (bit rate, delays, etc...). In order to reach such a goal, 3G standardization bodies have designed highly-flexible radio interfaces, characterized by a great number of physical parameters to be set by the operators. UMTS (Universal Mobile Telecommunication System) offers both circuit switched and packet switched transfer mode, and within each transfer mode, different QoS can be achieved by properly setting physical parameters such as the speed of physical channels, the power control scheme, the rate of the FEC protecting code, etc. We give an evaluation of the performance of W-CDMA UMTS radio access network (UTRA) when providing access to multimedia services. In particular, we analyze through detailed simulations a typical scenario where voice calls and Web-browsing sessions share the same frequency carrier, the former using the dedicated channels (DCH), the latter being transferred on the downlink shared channel (DSCH).