Data outage across 3G & 2G wireless networks

Service continuity between EGPRS (2G) and WCDMA (3G) systems has been identified as one key research item recently. Measurement from live cellular networks indicate that outage time for packet switched traffic during intersystem handovers are too long going up to one minute in some cases. In this article we analyze intersystem handover latency across 3G and 2G wireless networks. The inter-system handover focused on the service interruption during mobility using both of the main data protocols, TCP and UDP. The results showed that the data outage is high for TCP and UDP, up to 7s and 10s respectively and can considerably affect real-time user applications. Some proposals have been highlighted to improve handover performance including candidate features such as the packet switched handover feature in 3GPP Rel 7. The performance degradation mostly depends on the application type, transmission protocol, intersystem handover type, and bandwidth of the wireless access link.