Admission Control in the Downlink of WCDMA/UMTS

In this paper, we develop a novel CAC algorithm that takes into account the mobility of users inside the cell with a focus on the downlink of third generation mobile systems. We first study the system capacity in a multiple cell setting and obtain effective bandwidth expressions for different calls as a function of both their positions in the cell as well as their classes of traffic (voice versus data). We then use this formulation to derive a mobility-based admission control algorithm which we analyze by Markov chains. We hence obtain several performance measures, namely the blocking probability, the dropping probability, both intra and inter-cell, as well as the overall cell throughput. We eventually investigate the performance of our CAC and show how to extend the Erlang capacity bounds, i.e., the set of arrival rates such that the corresponding blocking/dropping probabilities are kept below predetermined thresholds.