Hot off the back of its spectrum wins in the digital dividend auction, Optus has flicked the switch on its 4G TD-LTE network in Canberra.

The network, which operates on the 2300MHz band acquired when Optus bought Vivid Wireless last year, is currently in customer trial mode, with Optus offering a 4G Dual band dongle and WiFi modem to access the network.

TD-LTE is a variation on the LTE technology currently in place by Australian networks, in that it uses the same frequency for uploads and downloads, but does each at separate times. Current LTE technology (FD-LTE) uses two separate frequency channels for uploads and downloads.

At present, there are few devices on the market that can operate on the new Optus network, meaning customers wanting to take advantage of the 4G speeds in Canberra will need to invest in the dual-band network dongle (which launches in June), but over time that is likely to change.

Optus plans to expand both its FD-LTE and TD-LTE network over the next 18 months, with plans to have the joint network covering 70 per cent of the metro population by the middle of 2014.

"Optus will be the first Australian carrier to take its network to the next level with a combined TD/FD-LTE 4G network. Our aim is to expand coverage for both types of 4G in the coming year to reach over 70 per cent of the metro population by mid-2014," says Andrew Smith, Optus' Vice President of Mobile Engineering.

Bigger network

Optus has also announced that its combined 4G/3G network has expanded to the point where it now covers 98 per cent of the population, following significant upgrades over the past year.

Over 4,000 3G sites around the country have been upgraded to 3GPlus, including both capital cities and regional centres, while over 700 sites have been upgraded to 4G (of the FD-LTE) variety as well.

What's more, the network plans on continuing the upgrades to the network to take advantage of the digital dividend spectrum it won in the 700MHz and 2500MHz bands. Optus claims that as soon as the spectrum becomes available to them, they'll start offering services to use it.

"Preparing our mobile network in the coming year for 700 MHz and 2500 MHz spectrum means when it becomes available for use, we'll be ready to flick the switch and give our customers swift access to the stronger 4G coverage it allows," Smith said.

"This strategy of combining 4G technologies – low-band 4G frequency for strong coverage, high-band spectrum to increase network capacity – gives Optus flexibility to meet our customers' need for additional capacity and faster network speeds," he added.