Device compatibility remains a key issue in VoLTE

LONDON--Mobile device compatibility remains a key obstacle to overcome in deploying Voice over LTE (VoLTE) services, according to several speakers at the LTE Voice Summit here.

Walter Zielinski, senior director of Huawei's core R&D department, told delegates here that not all LTE devices are created equally, in a presentation covering the challenges of integrating VoLTE and IMS into mobile networks.

"The terminal landscape causes a range of problems," Zielinski said, adding. "If we look at those devices…you will find out that the features across those devices are not uniform in terms of the support. Even if they are uniform they're behaviour is not the same…We found out that we have to do a number of customisations."

Huawei's device problems are not affecting South Korean operator LG Uplus, according to general manager Seunghyun Sung. Responding to a question from Alan Hadden, president of the Global mobile Suppliers Association (GSA), Sung said all of the operator's LTE handsets are compatible with VoLTE, which the company markets under the LG UWA brand.

Bejoy Pankajakshan, senior director solutions for architecture at Mavenir, noted that even device ownership can present challenges to operators. Multi-SIM handsets, for example, are increasingly popular among users who don't want to carry separate phones for business and their personal lives. That creates complexity for operators in enabling subscribers to access two lines on one phone.

"How you handle the questions when you have multiple devices, multiple lines…gets extremely complex in the network so those are areas that we are currently working on," Pankajakshan explained.

However, the question of devices goes beyond just being able to access multiple lines through a single device, Pankajakshan added. With consumers increasingly owning a smartphone and a tablet, continuity of service between those two devices is another challenge operators must overcome when deploying VoLTE.

"There's no specific spec in voice that handles multi-device voice. The other aspect is call transfer, if I receive a call on my tablet I want to transfer over to my cell phone," he said. "We only spoke about seamless handoff."

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