The Adaptive Modulation and Coding (AMC) scheme which handles user's mobility issue plays a significant role to improve the desired quality of service in High Speed Downlink Packet Access (HSDPA) networks. We develop a resource allocation which maintains constant bit rate for real-time (RT) and non-real-time (NRT) calls independently of the user position in the cell. We present analytical results relating to user performance in terms of blocking and dropping probabilities, and the results relating to the system performance in term of total throughput. We propose a call admission control scheme to derive a good trad-off between the blocking and dropping probabilities, and the choice of scheduling that efficiently utilizes the available resources.