Optus to launch 4G mobile network, better 3G too

Optus' mobile broadband speeds are set to ratchet up a notch when it launches its next-generation 4G mobile network in April next year.

It is also detailing how it has been upgrading its 3G mobile network in response to customer complaints that its performance is too slow for internet use.

Telstra has already launched a limited-scale 4G network using the same high-speed LTE technology, but has only made 2,000 modems available for sale to customers, while it checks that the technology is working well. Coverage is currently only available 5KM from Sydney, Melbourne and Brisbane city GPOs.

But first, an upgrade to the Optus 3G network

Optus will also start scaling-back its old 2G network, and use the radio spectrum freed up to add extra capacity to its 3G network for use with current-generation, internet-enabled smartphones.

Importantly, the radio frequencies made possible by reusing 2G network spectrum are in the low frequency 900MHz range, which will provide much better signals indoors.

Currently, Optus only promises mobile broadband speeds in city areas outdoors because its high frequency 2100MHz signal has trouble penetrating building walls adequately.

The number two-sized telco says it will start cutting capacity on its 2G network in order to boost the 3G network initially in Sydney, Melbourne and Perth this month.

Brisbane and Adelaide will get the upgrades "in coming months".

Optus says in the last year it has installed 660 new mobile transmitters and is yet to build 500 more. It is also upgrading the equipment at 2,500 existing sites for better performance.

It is catching up to the technology Telstra rolled out on its Next G network in 2009, with upgrades to 700 base stations to provide HSPA+ capability. They will have a theoretical maximum speed of 21Mbit/s, with a real-life top of about 8Mbit/s.

Telstra now uses the generation beyond what Optus is introducing -- HSPA+DC which has a theoretical speed limit of 42Mbit/s and in reality provides top speeds of up to 20Mbit/s.

The new Optus 4G mobile network

The first areas to get 4G mobile coverage from Optus will be the regional centres of Newcastle, Port Stephens, the Hunter Valley and Lake Macquarie.

Optus says it will start installing 4G into Sydney, Melbourne and Perth next month but the network won't be ready to switch on until mid next year.

An interesting aspect of the new network is that Optus is being given the chance to be the first carrier to use radio frequency freed-up by analogue TV, which has already been phased out in a handful of places in Australia.

The trial of 4G over TV frequencies (700MHz) will take place in Bendigo, Victoria. At such a low frequency, the signals should travel far, and easily penetrate building walls, providing very good in-building coverage.

The telco is being cautious not to promise any particular internet speeds through the 4G network, but the first-release LTE technology has a maximum theoretical speed of 100Mbit/s and in tests has provided real throughput of 40-50Mbit/s, and upload speeds of 20Mbit/s, making the upstream considerably faster than wired ADSL2+ and cable.

However, a key difference between a mobile network and a wired internet connection is that the maximum mobile speed is divided up between all users of a mobile tower, whereas the maximum wired internet speed is available to each internet user.

danwarne