ZTE continues to benefit from the latest wave of network upgrades from Chinese operators. The company has won a contract to help build China Unicom's IMS network.
The vendor announced it has been chosen as the leading partner for an IMS buildout in 10 northern China provinces, including Beijing.
ZTE will also help China Unicom transform its fixed network into an IMS network, and deploy applications including VoLTE and RCS over the network.
China Unicom's IMS upgrade is aimed at eventually transforming its fixed-line network into a full fixed-mobile convergence architecture.
Other provinces covered under the contract include Tianjin, Shandong, Heilongjiang, Jilin, Liaoning, Hebei and Henan.
ZTE made the first IMS call for China Unicom in 2010 and supplied an IMS network for subsidiary Qingdao Unicom which went live in 2011.
Last month, ZTE revealed it had won nearly half of China Telecom's tender for its LTE core network.