LIVE FROM BROADBAND ASIA, SINGAPORE: Japan’s SoftBank has successfully deployed TD-LTE networks to cope with the uneven distribution of data consumption across sites that impacted quality of service and was previously costly for it to address.

Han Gang, ZTE’s VP of TDD products, said at the event that because site resources are limited and expensive in Japan, SoftBank previously had to rent space at sites from other operators.

By moving to ZTE’s centralised RAN the operator was, he claimed, able to co-locate the TD-LTE equipment at its existing PHS sites, which greatly reduced costs.

The vendor’s C-RAN architecture, which combines the baseband unit (BBU) and remote radio unit (RRU), allows one BBU to support up to 18 RRUs. One rack can hold five BBUs and five racks can fit in a central equipment room – that’s a total of 450 RRUs.

Han said the advantage of this architecture is that the baseband resources can be shared, which is good for interference cancellation and increased capacity. “And if an operator needs to change one board in a BBU, it just needs to go to one site instead of hundreds, which results in large savings in opex.”

SoftBank now has more than 10 million TD-LTE subscribers, which represent two-thirds of its 4G customer base. It has deployed 54,000 TD-LTE base stations.

SoftBank is Japan’s third largest mobile player with 33.6 million connections for a 20 per cent market share, according to GSMA Intelligence. Half its customers now have smartphones.

Han said almost a quarter of 4G operators globally — 80-90 companies — have deployed both TD and FDD networks, and more are turning to TD (using unpaired spectrum) to boost their spectrum resources. The majority of 4G operators still use more widely available FDD (paired) spectrum on a standalone basis for LTE rollout.

He noted that many of the firms deploying TD-LTE networks in Europe are startups and former WiMAX operators.

ZTE ranked number 1 globally in TD-LTE base stations shipped last year, accounting for about one-third of the total, claimed Han. Supplies to China Mobile, of course, accounted for a high percentage of that.