German operator E-Plus is working with ZTE to deploy an IMS-based core network infrastructure, Telecompaper.com reported on Sept 15, 2014. This will be the basis for a commercial voice-over-LTE (VoLTE) service on the E-Plus network. With ZTE, E-Plus deployed the IMS core network within a few months and has already started testing VoLTE services for commercial use.

Compared with CSFB (circuit switched fall back) technology that makes voice calls ‘fall back’ to the 3G network, VoLTE provides higher-quality voice services for end users and improves the user experience. In addition, the eSRVCC (enhanced single RAN voice call continuity) flow for switching voice services from the 4G IMS network to the 3G CS network ensures that when an LTE user migrates from a place covered by the 4G network to a coverage hole in the 4G network, the user\'s voice services can be switched smoothly to the 3G network.

ZTE has been an E-Plus network supplier since 2009.