Optus has revealed plans to launch its own Long Term Evolution (LTE) mobile network in April next year.
The announcement makes Optus the third mobile carrier to announce an LTE network.
Telstra planned to launch LTE services in capital cities next month. Vodafone Hutchison Australian had voiced similar plans but was yet to announce launch timing.
Optus' first LTE services would be available in areas around Newcastle, Port Stephens, the Hunter Valley and Macquarie Valley from April next year, with capital cities Sydney, Melbourne and Perth expected to receive the capability a few months later.
Other major regional areas and capital cities, including Adelaide and Brisbane, would receive access to the network during a second rollout phase, though Optus did not specify when that would take place.
Optus planned to use an 1800 MHz spectrum band in its commercial LTE rollout, mirroring similar attempts by Telstra to use existing specturm holdings as a stopgap for spectrum reallocation in coming years.
It had also kicked off a 700 MHz LTE trial using Huawei gear in the Victorian town of Bendigo, ahead of the auctioning of digital dividend spectrum by the Federal Government in 2013.
"We need to ensure we use the best spectrum available to deliver 4G LTE technology," Optus chief executive officer Paul O'Sullivan said.
"Optus believes that 700 MHz will be vital for delivering 4G LTE, especially in regional Australia, because of its ability to deliver LTE over longer distances."
Günther Ottendorfer, managing director of Optus Networks, said the 700 MHz band would provide better coverage and indoor penetration than higher frequency ranges.
He said it was "too early to announce" commercial plans for the 700 MHz band, renewing calls for more certainty about availability of the spectrum.
"We expect next year that the Government will release that spectrum. We expect in 2014-2015 to have it available," he said.
"That will influence our rollout plans. The earlier the better for us," he said, describing the 1800 MHz rollout as the "first step for us in this space".
Ovum analyst Nicole McCormick said Optus' decision to "join the LTE1800 bandwagon" would improve the device ecosystem and regional roaming in that band.
She noted plans by Telstra, Vodafone, Japanese telco NTT DoCoMo and South Korean telco SK Telecom for LTE services in the 1800 MHz spectrum.
Metro 900 network switched on
Optus also unveiled plans to reallocate its 900 MHz spectrum bands in metropolitan areas from 2G services to 3G, marking the first time the carrier provided dual-band services to capital cities.
The telco had previously used dual-band services over the 900 MHz and 2100 MHz spectrum bands to provide greater coverage but had yet to do it in metro areas.
As part of the network boost, Optus would upgrade 2500 mobile sites and add 500 more to make the 900 MHz spectrum band available for 3G use.
The introduction of dual-band services would allow Optus to boost HSPA services to 42 Mbps speeds.
Those speeds would be made available in Sydney, Melbourne and Perth this month, with Brisbane and Adelaide upgrades to come later.
O'Sullivan explained that Optus had reserved its 900 MHz spectrum for 2G because most customers' 2G devices operated in that band.
"What's allowing us to redeploy this spectrum so that we can get broader distribution of our 3G signal and indeed get into more buildings is the fact that we're now at a stage where we've had sufficient customers who have migrated to 3G and they've freed up the spectrum for that use."
O'Sullivan said the carrier had invested $2 billion into its network over the past four years, including installation of 660 new mobile sites over the past financial year.
Updated at 12.25pm to include further details from Optus' media briefing in Sydney.