The Research On Measurement-based Call Admission Control For Cellular Mobile Network

As a important part of radio resource management(RRM) and a important method for providing the Quality of Service(QoS) of user in mobile communication, call admission control(CAC) has become a hot topic of research in the field of mobile communications.In this paper, based on the research and analysis of the existing call admission control algorithms for Cellular Mobile Networks, the measurement-based call admission control algorithm is studied. Aimed at the insufficiency of the existing call admission control algorithms not fully considering handoff and user mobility, the complex mathematical model, and the too simple theoretical setting of external factors which affecting algorithm performance, the main work, based on QoS requirements, is summarized as follows:1) According to combining of the physical model and call admission control algorithm, first, we establish a node model based on Random Walk Mobility Model, a regional model which is the cellular system of 19 hexagonal, and simulating the handoff and moving of all users in the cellular mobile system. Then we present a improved measurement-based call admission control algorithm utilizing time series analysis under the random model. The basic idea of this algorithm is that:it updates the reservation threshold (Th) by directly forecasting the next possible number of handoff dropping calls, using ARMA (auto regressive moving average) model. Then, we compare four important properties of improved algorithm to Timer algorithm under the same experimental condition, simulation results show that the improved call admission control algorithm is superior to the Timer algorithm in the new call blocking rate and resource utilization.2) In order to further study scalability of the stability and adaptability of the improved measurement-based call admission control algorithm, this paper compares the performance of algorithms of three different time sampling intervals(t) and three different cellular radius(R). Simulation results show that the parameters t and R have less impacting on this improved algorithm of wireless mobile network, and the algorithm has good stability and adaptability to adapt to varing network.Finally, the paper makes a summary and draws the prospect of research. Especially, it points out the focus and direction in the future research.