Abstract
This paper investigates the discontinuous reception(DRX) mechanism of Universal Mobile TelecommunicationsSystem (UMTS). DRX is exercised between the networkand a mobile station (MS) to save the power of the MS,which is controlled by two parameters: the inactivity timerthreshold and the DRX cycle. Analytic model is proposed tostudy the effects of these two parameters on output measuresincluding the expected queue length, the expected packetwaiting time, and the power saving factor. Our study quantitativelyshows how to select appropriate inactivity timerand DRX cycle values for various traffic patterns.