In this dissertation, we establish an end-to-end simulation model for the performance evaluation of WCDMA/ATM-based third-generation cellular systems where we take into account the quality of services in the integrated voice-data environment. This dissertation aims to provide a framework for performance analysis and evaluation of algorithms in mobile networks. In order to model such a complicated system, three challenges face us: modeling the wireless channel, modeling the traffic sources and modeling the broadband access network. In Chapter 1, the architecture of this system simulation model is concisely described. The authors contribution is to propose an abstract model of the air interface that has the same abstraction level as the broadband access network, which makes the integration of radio links and transport infrastructure feasible. The most important parts of this dissertation are in-depth researches on the three critical problems we mentioned above. Foreach topic, we derive an analytical model and implement it using Block Oriented Network Simulator (BONeS) of Cadence Corporation, USA.In Chapter 2, a digital channel model is established based on the simulation testbed which has developed successfully in the wireless communication laboratory in BUPT. This channel model is a key block in the abstract air-interface simulation module. The authors contributions are: