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ZTE in 4G boost after 'world-first' VoTD-LTE call

Landmark call could accelerate adoption of FDD alternative

Smartphone user on Tube

Chinese telecoms kit maker ZTE has moved to cement its place at the forefront of next-generation LTE services and fly the flag for the TDD variant by completing what it claims to be the world’s first voice-over TD-LTE (VoTD-LTE) call.

The Shenzhen-based firm’s TD-LTE equipment powers a China Mobile network in the nearby city of Guangzhou and it was here that the historic call was completed - on 5-mode, 13-band smartphones powered by Marvell chipsets.

ZTE claimed that VoTD-LTE calls using its IP Multimedia Subsystem (IMS) platform offer superior voice quality, lower latency and more efficient smartphone energy consumption than alternatives using CS Fall Back (CSFB) or dual standby methods, which effectively use 2G/3G networks for voice.

Other touted benefits of TD-LTE include higher spectral efficiency which means more voice customers can be supported on the same amount of spectrum, while the ability to integrate data and voice means operators can reduce operational complexity and boost the efficiency of their networks, ZTE said.

The firm is claiming this first will help accelerate the adoption of voice on TD-LTE networks, but that standard is playing catch up with rival FDD-LTE, which is favoured in Europe, the US and elsewhere.

Back in August 2012, network operators from South Korea and the States both claimed to be the first in the world to offer VoLTE services.

SK Telecom and local rival LG U+ both announced VoLTE services would begin under the HD Voice banner, while MetroPCS claimed “the world's first commercial launch of Voice over LTE (VoLTE) services” and began selling VoLTE-capable handsets at its Dallas/Fort Worth stores.

ZTE told The Reg back in February this year that the TDD variant was gaining momentum on FDD, but that it could take 10 or 20 years before the standards shake-out.

Unlike FDD, which requires a paired spectrum that has been criticised for being inefficient, TD-LTE transmits the up- and downlink traffic in the same unpaired frequency band, maximising available bandwidth and incurring lower power costs. ®

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