Optus has switched on its '4G Plus' network to serve Melbourne, Sydney, Brisbane and Adelaide, which will coincide with launch of Apple, Samsung and LG's new compatible TD-LTE smartphones.

The new '4G Plus' (TD-LTE) network will now be available in areas of Melbourne, Brisbane and Sydney after the successful pilot in Canberra, which saw Optus road test the technology with 4G TD-LTE modems.

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Optus' new TD-LTE network is being progressively rolled out across Australia's major metropolitan centres alongside existing 4G FD-LTE network.

Optus is now the only mobile provider to operate 4G from two high capacity network technologies after the network was switched on today by Victorian technology minister, Gordon Rich-Phillips at the National Tennis Centre.

These complementary networks will provide the necessary capacity required for the growing demand in 4G data services.

The network is currently only compatible with the Samsung GALAXY S4 mini and Samsung Galaxy S4. The Apple iPhone 5s and iPhone 5c will be available from September 20, and the LG G2 will be out in November.

The Optus 4G mobile broadband dongle and WiFi modem are both 4G Plus ready. Currently, all of Australia's 4G networks run on FD-LTE, which uses two separate frequency channels, one for data travelling in each direction. TD-LTE is a new flavour of 4G technology, where the upload and download of data happens on the same frequency, but at different times.

Optus vice president of corporate affairs, David Epstein said Australians could now experience life in the 4G fast lane with the Optus 4G Plus network.

"We're effectively adding more lanes to the Optus 4G super highway, letting more people use our 4G network at the same time,' he said.

"That typically means a smoother ride with a better mobile internet experience, both on 4G Plus and in the other lanes too.

"More lanes on the highway can help ease congestion for data hungry consumers."

It is expected that all mobile phone makers will start incorporating the technology into new phone models, as TD-LTE is used in some countries, and FD-LTE in others (along with countries such as Australia that use both).

Optus' new 4G Plus network operates on the 2300 MHz spectrum band. The current FD-LTE network runs off the 1800 MHz spectrum band.