China Mobile and KPN have claimed the first successful trial of international, IMS-based VoLTE (Voice over LTE) roaming between operators. The service is based on technology developed by KPN subsidiary and mobile operator solutions provider iBasis.

A time-frame for rollout of the service in the Netherlands has not been made public, but China Mobile has said it will be launched commercially in China at the end of 2014. The companies said iBasis and China Mobile International will be providing the IPX interconnectivity between China Mobile and KPN, while key network components are provided by Huawei.

The iBasis solution underlying the VoLTE implementation supports both local network breakout and home routing. The company claims operators can access hundreds of destinations across the world via a single connection to the iBasis multiservice IPX.

“Globalization and increasing demand for the high-quality of service of LTE are driving mobile operators to implement VoLTE and VoLTE roaming as the next logical step after deploying LTE in their national networks and LTE data roaming internationally, “ KPN said in a statement. “VoLTE represents a significant gain in network efficiency and end-user convenience. For example, customers will be able to make voice calls over the LTE network while downloads continue in the background.”

Other features apparently include HD voice and the ability to switch instantly between voice and video without any compromise to quality. “The trial proves the potential that China Mobile and KPN customers could enjoy the full VoLTE experience while traveling abroad when VoLTE has commercially been made available to its customers,” KPN said.

Gains have recently been made in the VoLTE space, for example by Nokia Networks and du pre, and with the market set to double next year, it will be interesting to see how quickly other operators jump on VoLTE roaming as the market matures.