Some QoS issues in 3G wireless networks

The research on QoS of 3G networks is becoming more and more, important. This paper discusses some problems about QoS in 3G networks such as: (a) introduction of the architecture of service differentiation in UMTS. Four QoS classes have been defined. Each class is intended to carry traffic of different kinds of applications. (b) The mapping of UMTS QoS to external IP network is given in order to provide users with end-to-end QoS. (c) As the "last hop" of the IP network, the wireless network has its own unique set of complex characteristics. As the methods of improving the behavior of the wireless link, some methods of optimizing TCP for wireless IP network are presented to meet end-to-end IP performance.