Static RRC Timeouts for Various Traffic Scenarios

The operator of an UMTS radio access network has to define timeout thresholds for the radio resource control protocol. These timeouts have a strong influence on the quality of service of the user traffic. In general long timeouts favour the call setup time over the outage probability. For short timeouts it is the other way around. Furthermore the reached quality of service level depends on the load in the system. The load consists of the number of users in the system and the services they are using. This paper investigates the relationship between these both parameters and the previously mentioned quality of service parameters. We present results of five different timeout settings, tested in various network settings. Simulations show that very high timeout values have an insignificant influence on call setup time but increase the outage. We highlight two timeout settings which fits the requirements on user experience and operators expectations best.