Until the development of IP Multimedia Subsystem (IMS) networks and adequate Long Term Evolution (LTE) coverage is provided, operators will continue to provide voice services with UMTS Terrestrial Radio Access Network (UTRAN) and GSM EDGE Radio Access Network (GERAN) network at the core of the Circuit Switched Fallback (CSFB) feature in LTE. CSFB is the most known and used method to promote voice services over LTE networks today, as the deployment of IMS is still in its beginning. CSFB is a way to switch from LTE technology to UMTS or GERAN technology. This transition has some advantages and disadvantages. In this article, we discuss the performance of CSFB voice traffic redirection and handover method from LTE to UMTS using data from live commercial networks. The key factors impacting CSFB call setup delay and data interruption time are highlighted. In this paper we present the results of CSFB PS handover (HO) and PS redirection over 3 different phone brands in terms of voice call setup time (VCST) and data transfer interruption time (DTIT) indicators. In the handover technique, while the duration of VCS increased, it was observed that there was a significant improvement in the duration of DTI. Results obtained as expected that data transfer interruption time is reduced %93 on PS HO method.
Anahtar Kelimeler: Call Setup Time, CSFB, Data Transfer Interruption Time, PS Handover, PS Redirection
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