Hong Kong has begun an industry consultation on releasing a further slice of 4.9GHz for 5G.

The city last year auctioned off 380MHz of sub-6GHz 5G spectrum, including 80MHz of 4.9GHz frequencies. The first 5G commercial services began in April.

One reason for deploying in 4.9GHz is that the band has already been allocated to two mainland China operators, China Mobile and China Broadcast Network.

Outside China, so far only Japan and Russia have committed to it. However, in a consultation paper issued Thursday, the Communications Authority (CA) said it believed "local and worldwide developments" in 4.9GHz adoption would ensure that network equipment and terminals would become more commonly available.

An even more significant attraction of 4.9GHz is that it can be used right across the city.

The mobile industry in Southeast Asia has been in conflict with satellite broadcasters over the 3.5GHz band, which overlaps with satellite broadcast services. To avoid interference, the regulator has set up an exclusion zone in northeast Hong Kong, covering approximately 10% of the population.

As the CA puts it, compared to 3.3GHz and 3.5GHz, "the 4.9GHz band has the advantage of being able to support deployment of 5G services at all indoor and outdoor locations in Hong Kong."

Two operators, China Mobile and HKT, paid HK$120 million (US$15.5 million) for each of the two 40MHz of 4.9GHz blocks auctioned last October.

The CA said it had recently vacated 50MHz of 4.9GHz spectrum that was being used by government agencies. It proposes combining this with 30MHz of reserve spectrum to create two more 40MHz blocks. It suggests limiting each bidder to a maximum of 40MHz.

The new frequencies would likely be most attractive to Hutchison and Smartone, who have the smallest spectrum holdings overall and the smallest in 5G, with just 70MHz apiece compared with the 120MHz owned by HKT and China Mobile.

The CA paper proposes allocating the spectrum through an auction as with the other 5G frequencies, and requiring the successful bidders to provide at least 50% coverage within five years.

— Robert Clark, contributing editor, special to Light Reading