China Mobile demonstrates 3.3 GHz TD-LTE, in bid for additional spectrum
The 3.5 GHz band has been in the spotlight because of the USA’s very specific plan for the spectrum, but elsewhere in the world, frequencies from 3.4 GHz to 3.6 GHz have been allocated for years for fixed broadband wireless, and are increasingly being adapted for TD-LTE as regulators have allowed mobile hand-off too. The band is now expanding down to 3.3 GHz, following World Radio Conference last November, and China Mobile and Huawei have completed the first live demonstration of an end-to-end TD-LTE system in 3.3 GHz to 3.4 GHz spectrum.
As operators turn their attention from coverage-oriented initial LTE roll-outs, to expanding capacity, they are more interested in higher frequencies, which support large capacity. In this context, TDD technologies are becoming more appealing, even to operators which have only used paired spectrum in the past, because TDD allows flexibility in provisioning uplink versus downlink, and is well suited to data-intensive usage and to the small cells which inhabit high frequencies with their short range.
All this will make the often neglected spectrum above 3 GHz gain new value and interest. At WRC-15, 300 MHz of contiguous C-Band spectrum (3.4 GHz to 3.8 GHz / 3.8 GHz to 4.2 GHz) was earmarked for 4G use in 45 countries in regions including APAC, Africa and Latin America.
Now some countries and organizations are lobbying for that to be extended to the 3.3 GHz to 3.4 GHz spectrum. The push is led by Chinese operators, all of which have been allocated TDD spectrum, and particularly by China Mobile, which has almost single-handedly created a global ecosystem around TD-LTE, seeking to avoid the lonely technology island on which it sat with its imposed 3G system, TD-SCDMA. The 3.3 GHz bid is supported by the China Communication Standards Association, and if it does become a global LTE band in future, it can be expected that Chinese organizations will be the main drivers behind equipment and IPR.
The China Mobile/Huawei demonstration was conducted at a workshop in Shanghai run by the Global TD-LTE Initiative (GTI), which promotes and advocates for TD-LTE technologies and interoperability worldwide. The test network used modified commercial Huawei 3.5 GHz TD-LTE products, indicating that there would be no need for entirely new equipment and device development if 3.3 GHz were approved.
“GTI is committed to the advancement of consistent C-Band spectrum planning around the world, and the 3.5 GHz Interest Group established in 2013 has quickly accelerated industry chain maturity,” Huawei said in a statement. “More than 40 global operators, with over 60 commercial terminal models, currently integrate commercial and pre-commercial network deployments on the 3.5 GHz band. GTI will continue to cooperate with global industry partners to promote C-Band TDD-oriented planning and contribute to further implementation at the national level and into the international standardized organization 3GPP specifications.”