Optus 4G

Early this morning, Jason Murray and I attended an Optus network briefing in Sydney, presented by Guenther Ottendorfer, Optus’ Managing Director of Networks and Andrew Smith, Vice President of Mobile Radio Engineering. The focus of Optus’ briefing was to discuss the improvements to Optus’ network over the last twelve months, to look at what’s coming in the next few months and further down the road.

Given that I get a lunch break, I thought we’d share the highlights with you.

Optus network, today

Optus has been spending a fair bit of time and money (upwards of $2bn) on expanding its network in the last couple of years, and the results have paid off. Optus now claims a reach of 98% of the Australian population, using ‘real world’ measures. Unlike Telstra, which measures coverage using external antennae, Optus conducts this measure using a range of handsets to determine coverage that the average person can see.

If Optus were to include the extra coverage that is attainable with an external antenna, this figure would increase to 98.5%. This might not sound like much, but it is a huge amount of actual land coverage, given our sparse population.

This coverage includes 4G and 3GPlus (i.e. 2100 MHz + 900 MHz), though of course the 4G footprint isn’t as large.

Ottendorfer said:

Reaching these milestones is just the beginning. Our focus over the coming year is to continue strengthening our 3G network, growing our 4G network, and expanding our 4G technologies to include TD-LTE, starting with the launch [of TD-LTE] in Canberra.

Optus’ network, tomorrow

Optus today announced that it’s switched on a 4G network in Canberra, but unfortunately for Optus customers in Canberra, you probably won’t be able to use it for a while. The coverage maps look good — as well as you could expect them to look with 12 base stations in an initial rollout — but coverage isn’t the issue. Rather, this network doesn’t run on Optus 1800 MHz network that it uses for 4G elsewhere, but rather a 2300 MHz network using a different technology – Time Division LTE instead of Frequency Division LTE which Australia’s current 4G networks use.

For those not familiar with the difference, FD-LTE essentially uses two separate frequency channels, one for downstream and one for upstream. TD-LTE on the other hand uses a single frequency which is split up into a number of time-slots. This allows variable use for downstream and upstream and can readily be changed on the carrier end. At present, the Canberra roll-out is using a 3 to 1 ratio, meaning 3 downstream slots for every 1 upstream.

With this in place, Optus has seen network performance of upwards of 60 mbps, while acknowledging that the average customer probably won’t notice nor care about this metric. Optus is keen to expand this network more widely, says Smith:

Optus will be the first Australian carrier to take its network to the next level with a combined TD/FD-LTE 4G network. Our aim is to expand coverage for both types of 4G in the coming year to reach over 70% of the metro population by mid 2014.

While the TD-LTE footprint is largely restricted to Canberra (there are two test-sites in Sydney which you can’t really use), this should rapidly expand in the next twelve months. At present, access to this network will largely be restricted to dongle-type devices, with handset manufacturers expecting to take some time to incorporate these new frequencies and network flavours into their offerings. USB dongles and WiFi modems which can access this new 4G network should be available from next month.

Optus’ network, beyond tomorrow

Following the recent spectrum auctions, Optus plans to spread its 4G footprint significantly using its 700 MHz and 2500 MHz holdings. Optus will use its 700 MHz footprint for coverage, while using the higher frequency (and lower propagation) 2500 MHz network for extra capacity in higher density areas.

This really should come as no surprise, as we know that lower frequencies are great for super-long distance coverage, with the catch that the bandwidth itself doesn’t lend itself to the fastest speeds. In CBD areas, where cell towers are far more densely packed, the signal propagation properties of 700 MHz aren’t needed, and the 2500 MHz network will enable really quick data speeds for those that need them.

Jason and I spoke to Smith after the briefing and questioned him on handset support for these new networks. Observing that there’d be some four or five LTE frequencies operating in Australia, and many more worldwide, we asked Smith how he saw handset manufacturers supporting the unique combination of frequencies that are, or will be, in use in Australia.

Smith told us that these days, chip manufacturers (using the example of Qualcomm) can easily support all these frequencies, and more, in their chipsets today. The only limiting features is the OEMs being required to cater for those frequencies in their handset designs, in terms of form factor, antenna design and power consumption. What this should mean is that, unlike the days when Telstra introduced its Next G network and there were very few compatible handsets available, we should see — and quite quickly — the release of handsets that will support four, five or even six different LTE frequencies and interfaces (FD and TD LTE).

This means that the customer will not notice the transition from one network to another, and can easily move between carriers as well without concern for frequency support. It’s an ambitious goal, but one we hope that Optus is right about; the last thing we want to see is further fragmentation of the smartphone market on something as technical (and confusing to the customer) as different frequencies and technologies.


Optus is well aware that it has, in the past, played second fiddle to Telstra and it has burned a lot of money, time, blood, sweat and tears in closing the gap. From their presentation today, it’s easy to concede that the gap between Optus and Telstra is extremely narrow, and in some places, Optus has probably pulled ahead.

Our experience has varied, but Optus’ network does beat out Telstra’s in metro performance, but Telstra still (colloquially) has the coverage advantage. It’s probably time for another Ausdroid road test, to take three identical handsets with SIMs from each of the major carriers across the country and see what performance we can see where. A project for another day.

What are your thoughts on all this? We know it’s rather technical, but if you take nothing else away from this, it certainly looks like Optus is spending big on its network, and it does (or will) present a real alternative for those sick of the incumbent.