Introducing 3G like conversational services in GERAN packet data networks

In this paper a technical analysis as well as measurement results from a test bed activity have been presented demonstrating the feasibility of 3G-like conversational and multimedia services (such as video telephony, VoDP and push to talk) over a GERAN packet data network. Both conversational QoS requirements and network latency constraints have been deeply investigated and specifically addressed. The end-to-end (E)GPRS network performance has been analyzed in terms of one-way mobile-to-mobile transfer delay depending on IP packet size, radio conditions/applied coding scheme and especially taking into account the benefits of the upcoming extended uplink TBF feature. An extensive experimental study on an existing 3GPP Release 4/5 compliant (E)GPRS network has been carried out assuming different real world scenarios. Measurement results for ping, voice and packet video services have been provided and analyzed. The extended uplink TBF feature significantly improves the mobile originated ping to a network server as a fundamental metric and key performance indicator from 460 ms down to 260 ms. Furthermore a typical mobile-to-mobile audio packet delay of roughly 300 ms to 350 ms as well as video packet delay in the order of 450 ms to 650 ms have been obtained resulting in an acceptable voice and video perception. Hence seamless conversational and multimedia services are feasible both in UMTS and - with some tolerable performance degradation - as well in GERAN packet switched data networks currently deployed in the field all over the world leading to an important convergence of 2G and 3G networks, services and solutions.