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Optus boosts 4G network with carrier aggregation

Optus has launched LTE-Advanced carrier aggregation on its 4G network, ahead of the expected release of four compatible devices in the next few months.
Written by Josh Taylor, Contributor on

Optus has combined two 20MHz spectrum channels in the 2.3GHz spectrum band to boost its 4G network speeds as part of a long-term evolution (LTE) Advanced carrier aggregation rollout.

The launch across Sydney, Melbourne, Brisbane, and Adelaide of the TD-LTE carrier-aggregated network will allow users to access theoretical speeds of up to 220Mbps, Optus said, with single user speeds delivering 160Mbps speeds today. The network is live today, but no devices are as of yet available.

FD-LTE, which most networks operate on in Australia in the 1800MHz band, has dedicated slots for uploads and downloads, while TD-LTE uses the entire spectrum allocated to it for both downloads and uploads, separated by time.

Optus has already been using the 2.3GHZ spectrum band in Canberra for its 4G network where the company doesn't have any 4G spectrum in the 1800MHz, and LTE-A is expected to come online in Canberra in the coming weeks.

Previous tests of LTE-A using the higher-frequency spectrum with four channels have delivered download speeds of 520Mbps.

Although there are no compatible devices in the market today to access the network, Optus' managing director of networks Vic McClelland said that the rollout of TD-LTE Advanced was about "future-proofing" the 4G network, which Optus is aiming to reach 90 percent of the Australian population by April 2015.

"We are future proofing our network in response to consumers’ growing appetite for mobile streaming, browsing and downloading," he said in a statement.

The telco said customers with compatible devices, when they are made available, can expect "up to two times faster data speeds" than experienced today.

"While still in its infancy, carrier aggregation will lift the speed limit on the 'network highway' and support data-hungry customers," it said.

Optus' biggest rival, Telstra, is also working towards LTE-A with the 1800MHz spectrum and the 700MHz spectrum bands, with the first compatible device expected to be the new Samsung Galaxy Note 4.

Telstra, unlike Optus, is using FD-LTE for its carrier aggregation, and Telstra's general manager for wireless network engineering Channa Seneviratne said earlier this month that FD-LTE offered much better consistency than TD-LTE given the communication isn't divided by time.

"We think FD is a lot more efficient with some of the testing we've done," he said.

"With TD, you've got to time-slice it, and with the testing we've done with FD, you get consistently better, faster speeds."

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