Radio resource management (RRM) plays an extremely important role in efficient utilization of the limited radio resources to provide guaranteed quality of service (QoS). Power and transmission rate cotrol are considered as two primary RRM components in mobile cellular systems. The former method is well-known for upholding required signal quality and reducing the energy consumption, while the latter is used to maximize the system throughput. In this thesis, the algorithm of simultaneously adapting transmission power and data rate to maximize system throughput and minimize the power consumption for W-CDMA system is proposed . The greedy rate packing (GRP) allocation scheme is applied in the rate adaptation, where the higher transmission rate is assigned to the users with better channel conditions meanwhile mminimizing the transmission power. It can be interpreted that more resources, such as power and transmission rate, are allocated at time instants when channel conditons are favourable. As a result, the resource allocation will be working in an efficient way. Another problem in power control is that using fixed stepsize power control (FSPC) can not fully react to the changing of the fading fluctuations when mobile speed changes. A novel dynamic stepsize power control (DSPC) algorithm  is presented as well, so as to enhance the system performance. The performance of the proposal algorithms are evaluated through computer simulations, and compared with the traditional approaches from the literature. We model and stmulate all major components of the system within an accurate frame/time slot structure specified in the UMTS W-CDMA system. Numerical results verify that significant performance improvement can be achieved with the proposal algorithms.