Telstra Hits Back At Optus' Next-Gen 4G Claims

"Correction". That's what Telstra had to say about Optus' claim earlier today that it has launched Australia's first LTE-Advanced mobile data network.

Telstra is in the right, technically.

It upgraded a few towers on the Sunshine Coast north of Brisbane to support LTE-Advanced carrier aggregation in the middle of August last year, and at the same time launched a new 4G Advanced hotspot supporting the technology. This particular carrier aggregation implementation uses paired 900MHz and 1800MHz 4G bands, and theoretical 300Mbps download speeds.

What confuses the matter, though, is that Telstra then announced, in July of this year, a second LTE-Advanced network rollout in Perth, Fremantle, Esperance, Mildura, Mt Isa and Griffith. This rollout is on the paired 700MHz and 1800MHz 4G bands, and there was an accompanying 4G Advanced Pro X hotspot.

This is also the carrier-aggregated network pair that the new Samsung Galaxy Note 4 will almost certainly support, sporting the fastest possible download speeds on an Australian mobile network. What those speeds are going to be, we're not yet sure.

So Telstra has two LTE-Advanced networks, and has bragging rights of being the first. In practical realities, neither Telstra or Optus can lay claim to that crucial combination of widespread next-gen 4G across the country and easily available compatible smartphones or Wi-Fi hotspots.

Optus' LTE-Advanced 4G is more widespread, and focuses on the country's populous capital cities, for what it's worth, so there's still stiff competition brewing between Australia's top two telcos.

It's not clear whether the earlier 900MHz and 1800MHz network is still being worked on, or whether the 4G Advanced hotspot is a casualty of the rapid pace of technological progress — which would be a pity. We're checking with Telstra for clarification and will let you know.

Either way, Telstra did have the first next-gen 4G network, even if only in a smaller footprint than Optus's current capital city rollout. [Telstra]



    This is more a preparing for the future thing for both networks.

    By 2016 we will see a wide range of handsets supporting carrier aggregation. Telstra's CA over 900 and 1800 might get a boost with the closure of the 2G network by 2016 too, as it will be able to reallocate all of that spectrum to 4G but by then 700/1800 might be the norm for CA and all the 900MHz spectrum is just for capacity relief and older devices (like the hotspot pictured above)

    Since China is widely rolling out TD based 4G networks, like Optus here, expect to see a lot of devices using TD aggregation in the next year or two. From what I understand, it's technically not possible to combine TD and FD 4G types for carrier aggregation so a future device might end up supporting carrier aggregation on TD 2300+2600 and FD 1800+700 for example.

    There is a TD band at 700MHz (band 44) but it's not widely planned or in deployment, unlike Band 28 (FD at 700MHz) which is in use or planned to be in use over most of the Asia Pacific as well as Europe.

      I'm checking with Telstra whether they'll be doing 900+1800 AND 700+1800 over LTE-A. If they are, that's awesome. If they're not, I won't be surprised, since it seems everyone is placing their bets on (and pouring money into) 700+1800.

      Thanks for the TD-LTE China stuff, I didn't know that. I have to hang out on Whirlpool more often :)

        China Mobile (just 1 carrier there) plans to install 500,000 TD-LTE base stations across 300 cities in China by the end of 2014:

        That's incredible when you consider the entire Telstra network is only around 7,000 base stations.

        Thanks for the reply. It will be interesting to see if any more articles popup in future after your discussions with Telstra.

        Post 2016 as a customer I'd really like to see them use all the 900 spectrum for LTE, but when they already have 2 x 20MHz of 700 they will probably just keep 900 for capacity relief in busy areas.

        What might change things quite a bit is the ACMA reallocation and possible reauction of 900MHz - if each of the carriers could get 15MHz or 20MHz instead of the 8.4MHz all 3 were issued with when GSM started in 1992 then all 3 carriers might consider a partial or full refarming of 900 to LTE.

        Last edited 22/09/14 5:21 pm

        What is the difference between FDD & TDD

        I'm not sure on the underlying standard, but it will be 700, 1800 & 2600.

          FDD = Frequency Division Duplexing
          TDD = Time Division Duplexing

          FDD can download and upload data at the same time but using two different frequencies - spectrum of a carrier is divided into 2 separate lots - one group for the upload channels, one group for the download channels. How many channels an individual device uses depends on how many other devices are using data at the same time. As more and more devices are used, less and less channels can be used at once, hence the data is slower.

          TDD can only download and uplod data on one frequency, but at different times. So an individual device is still going to make use of many different channels at once to give it speed, but it will wait until the download of the packet is complete before sending the upload packet.

          For that reason, TDD is virtually useless for online gaming, video chat and voice calls, and FDD is preferred for that. TDD has a lower maximum speed than FDD, but that is purely in theory - depending on the device, the terrain, whether you are indoors or not, how many other users there are on your base station, etc the reality at your particular location maybe different.

          It seems to be a bit of a religious debate between various carriers over whether FDD is more efficient than TDD at a given frequency range and a given application. I guess real life experience of users will win out in the end.

          Hopefully this is making sense :P

          Last edited 22/09/14 5:49 pm

            This is WRONG and makes no sense at all. TD-LTE have a switch time of either a half-frame or one frame, that's 5 or 10 millisecond. If you call that added 5/10 ms "virtually useless for online gaming, video chat and voice calls" then I'd call EVERY SINGLE mobile technology useless for the very same reason.
            The DL/UL switch is mandatory and synced (via GPS/nework) across the entire network, so it will NEVER WAIT.

            Last edited 23/09/14 12:54 pm

              I think his information is slightly out-dated(in regards to the limitations), the type of system and he is suggesting and its limitations remind me of how our SME described CDMA networks and how each packet arrives in the same order it was sent, and a lot of other things.

              So not correct when applied to current 4G networks, but it still has merit, when in the correct context.

              After a bit more research, Telstra L700 is definitely a TDD network, with a requirement for a GPS receiver to be installed at each site, with VoLTE(Voice over LTE) being tested

    I think you'll find the time slices for TDM are imperceptible in real world applications. GPON, used in all fibre FTTX uses TDM and there is no problem supporting HD Skype, gaming etc. As with all networks it is congestion that will impact the user experience. And that is why both wired and wireless, in tandem, are the best option. Traffic that can be accommodated on fixed networks should be cheaper to the consumer and higher performing. When on the move use the mobile network. When in reach of a WiFi network, connected to a wired network, use that.

    So... Optus has been caught lying about their mobile network yet again. What a surprise.

    Cool, now you can have good speed in your blackspots! I only get 2 bars edge in a inner city suburb in Queensland standing outside my house on Optus. Moved to Telstra and I get full 4G.

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