In future, to cope with the increasing demand for mobile and personal communications, a two-tier CDMA cellular system with microcells and overlaying macrocells are likely to be deployed. In the operation of this system, slow-moving mobile users should be assigned to microcells and fast-moving ones to overlaying macrocells in order to minimize the total number of handoffs. Then the problem is how to find the thresholds to do the partition of fast-moving and slow-moving mobile users based on the estimated their speeds.
In this thesis, two methods for the mobile speed estimation are proposed and two operation schemes for micro-macrocellular CDMA system are suggested. Based on these, the offered average traffic to microcell and macrocell are analyzed respectively. Optimization models to find the optimal thresholds for micro-macrocell selection are developed in view of minimizing weighted total number of handoffs, which are subject to the constraints of QOS. And algorithms to find optimal solutions of the models are devised.
