Impacts of inactivity timer values on UMTS system capacity

UTRAN is a 3G radio access network based on the wide-band DS-CDMA technology. An important feature of UTRAN is its multimedia service capability. UMTS supports high bit rate and variable bit-rate services, packet data and Internet access. When a user sets up a data session, a downlink code is allocated. In UMTS, unless a secondary scrambling code is used, there is a shortage of downlink codes. We study the impacts of inactivity timer values on UMTS system capacity.