The high-speed Long Term Evolution technology powering the 4G networks of the future isn’t just limited to Telstra anymore, as rival Optus launches its own next-generation mobile network.

Arriving September 15, the next generation of the Optus network will be rolled out to Sydney, Perth, Newcastle, and Melbourne, with more cities and regions to come.

“We’re excited about the new opportunities that 4G will provide for Optus customers,” said Kevin Russell, CEO of Optus in Australia. “Whether that’s downloading multiple songs at the same time, or uploading videos and photos to social media, customers will love the experience and speed that Optus 4G has to offer.”

Sydney's coverage map for the Optus 4G roll-out, starting on September 15.

With the building of the 4G network, Optus claims the 3G network has been strengthened, resulting in stronger performance for all mobile users.

For the launch, Optus has announced that it will be grabbing a 4G variant of the Samsung Galaxy S3, arriving just in time for the middle of the month launch.

Currently available 4G mobile handsets will be compatible with the Optus network, thanks to the network using the same 1800Mhz band as Telstra’s 4G network, though representatives for the company stress that “non-Optus supplied devices aren’t supported by Optus technical support and we cannot guarantee their interoperability on the Optus 4G network.”

The 4G Galaxy S3 will be available in black and gray.

You cannot, however, just bring your own phone and hope your regular Optus SIM lets you use the new 4G connection, with an Optus representative telling GadgetGuy that “customers won’t need a new sim, but will need to change to a new 4G rate plan.”

Only post-paid plans are available at this time, with pre-paid missing in action for the initial burst of 4G Optus plans.

These plans are the typical two year plans starting at $60 per month and including at least 1.5GB of downloads per month.

Mobile users won’t be the only ones able to try out the Optus 4G network, with two mobile data devices released, including a USB 4G dongle and a portable WiFi modem. Each of these devices are available on one or two year contracts, with prices starting from $34.95 per month.