Last year, two carrier aggregation was seen as a stunning example of LTE-Advanced network innovation. Now it’s old hat, with three-carrier aggregation gaining all the plaudits.

ZTE, China Mobile and Qualcomm are the latest to get in on the game, having jointly completed a successful demonstration of TD-LTE commercial three-carrier aggregation in the downlink. The demo used ZTE’s TD-LTE eNodeB and EPC devices, based on terminals powered by Qualcomm’s Snapdragon 810 processor with X10 LTE modem. Three 20MHz carriers in the 2.6GHz TDD frequency band were aggregated, and the downlink data throughput rate reached 330Mbit/s. The companies say that this demonstrates that 3x carrier aggregation technology is mature and can meet commercial deployment requirements.

Last week, Telefónica also demonstrated three-band carrier aggregation over a live network at the MWC industry event. It used Ericsson network equipment to combine three component carriers (20MHz in the 2.6GHz band, 20MHz in the 1800MHz band and 10MHz in the 800MHz band) to demonstrate speeds of up to 375Mbit/s downlink and 50Mbit/s uplink. The latter band used a wired connection, as it is still being used in Spain by TV broadcasters.

Telefónica already offers LTE-Advanced services on dual carrier aggregation in Madrid and Barcelona, and will launch them in other cities of Spain during this year. Of course, actually using them requires the use of a suitably enabled LTE Cat 6 handset, and these are few and far between. I was able to test the service using a modified Asian Samsung Galaxy Alpha device and achieved impressive speeds during the week of between 86Gbit/s and 150Gbit/s (see image above for screenshot of actual results); still someway short of the company’s promised 225Mbit/s maximum, but mightily impressive nonetheless.

As for three-band use, that will require a Cat 9 handset. For Telefónica’s trial, a Samsung Galaxy Note 4 was used.

“Telefónica is making fast progress toward building a network designed with the future in mind,” said Enrique Blanco, CTO Telefonica. “Carrier aggregation represents one of the most efficient ways to leverage our spectrum, increase capacity and substantially enhance Quality of Service.”