LTE voice stop-gap: ZTE and CSL demonstrate Circuit Switched Fallback

18 Nov 2011

ZTE Corporation and Hong Kong mobile network operator CSL have successfully demonstrated a solution to provide voice services for Long Term Evolution (LTE) mobile broadband data service users based on the Chinese vendor’s ‘Uni-Core’ Circuit Switched Fallback (CS Fallback) using a commercial smartphone on CSL’s LTE network at the GSMA Mobile Asia Congress (MAC) in Hong Kong.

CS Fallback is intended to support the migration from 3G to LTE/evolved packet core (EPC) without the requirement to upgrade infrastructure, enabling usage of both high speed mobile data services over LTE and high-quality circuit switched voice services. CS Fallback is a standard defined by the 3rd Generation Partnership Project (3GPP) as a preferred solution in the early stages of LTE/EPC network deployment. ‘ZTE’s CS Fallback solution helps operators save costs by making full use of existing networks to provide voice services,’ said ZTE president of Core Network Products Xu Ziyang, who continued: ‘The joint demonstration conducted today with CSL shows that ZTE’s LTE voice solutions are viable and useful for mobile operators.’

Twelve months ago, in cooperation with the GSMA and CSL, ZTE successfully conducted the world’s first IMS based Voice-over-LTE (VoLTE) call on a commercial LTE network at MAC 2010.

Hong Kong, CSL (now part of HKT/PCCW), ZTE