Tag Archives: VoIP

Performance of CS Fallback from LTE to UMTS

One of the key challenges for telcos deploying LTE networks is to provide voice services. While many solutions have been proposed, Circuit-Switched Fallback (CSFB) and Voice over LTE (VoLTE) are currently the two most talked about options. A new paper in the IEEE Communications magazine looks at CSFB performance in great detail. Here’s an excerpt from the abstra

Analysis results in well optimized deployments show that on an average, MO/MT call-setup time for CSFB from LTE to UMTS is around 1 sec greater than legacy UMTS. However, the results can vary depending on the network configuration and the conditions of the measurement. To illustrate the optimization of CSFB performance in real networks, we also highlight the principal call set up optimization and implementation factors impacting CSFB call setup delay and success rates. This article demonstrates that in well optimized networks, CSFB to UMTS call setup success rates can be very close to those achieved in the legacy UMTS systems.

Link to the paper

The reader is also referred to an Alcatel-Lucent whitepaper on the same topic.

Options for Providing Voice over LTE and Their Impact  on the GSM/UMTS Network