Abstract—3GPP has been enhancing UMTS networks by issuing
new standard releases recurrently. However, the RRC state
transition model has remained rather unchanged through several
releases, namely, Rel. 99, Rel. 05 and Rel. 06. We review
RRC state transitions and study them in practice using our novel
3G Transition Triggering Tool (3G3T), focusing on the network
configuration parameters that prompt these transitions.
We employ 3G3T in a landmark measurement study involving
four UMTS networks in three countries and validate our findings
using a state-of-the art proprietary measurement tool. Our
results show that 3G3T is able to discover RRC configuration
parameters without operator involvement or cooperation. We
observe significant differences in UMTS network configurations,
which directly impact end-user data service performance.
We find that, in practice, the behavior of public UMTS networks
cannot be solely described based on the theoretical constructs
found in the literature, and that tools such as 3G3T are
necessary in order to obtain a complete picture. The results presented
in this paper aim to assist simulationists in developing
better models for UMTS networks. Moreover, we expect that
operators can use 3G3T to configure their networks more efficiently.
Finally, our methods and algorithms should be of great
interest to application developers for mobile broadband networks
based on 3GPP standards.