ON THE ACCURACY OF MOBILITY MODELLING IN WIRELESS NETWORKS

Abstract

In a wireless mobile network, two major problems arise: poor performance of the wireless layer and effect of user mobility. The problems related to limited available radio bandwidth and radio channel errors seem to be solved by CDMA technique applied in 3G mobile systems. The bandwidth that is provided by CDMA air interface is enough for present mobile multimedia applications. However such applications are sensitive to the degradation of QoS parameters. Graceful degradation could happen when too many mobiles arrive to the same radio cell. To avoid such situations the Call Admission Control (CAC) has to limit the number of newly accepted connections. Terminal mobility causes problems in call admission control because the number of active mobile terminals in a cell is a random variable. In this paper we introduce a new method to predict the number of terminals in each cell. Based on this information a more effective CAC algorithm can be applied in order to ensure user´s satisfaction.