LTE or "Long Term Evolution" is the standard that most of the world takes for granted as 4G, but its reign at the top of the wireless tables is set to be eclipsed by its successor – LTE-A, with the A standing for "Advanced."
4G networks often deliver speeds several megabits faster than many ADSL2+ networks, some of which struggle to pump out even 6 Mbps speeds, even though they’re rated at a theoretical maximum of around 20 Mbps – something you’ll only see if you’re quite close to your local telephone exchange.
Meanwhile, an iPhone 5s I’m using on Telstra’s existing 4G network just pumped out speeds of 13.18 Mbps (after boosting straight past 20 Mbps before slowing back down), with an upload speed of 14.06 Mbps, after quick testing with the Ookla Speedtest.net app.
But faster speeds, as always, are on the way.
Although Telstra announced that it had already trialed another LTE standard known as LTE-B (B for Broadcast) back in October 2013, which the company says allowed it to demonstrate “that it’s possible to use one stream of data, to deliver the same content to multiple users [with LTE-B capable devices] – keeping the rest of the network free for other customers”, the big news today centers around the company's latest LTE-A trial.
Using a combination of spectrum at 1800 Mhz and 2600 MHz, Telstra says it has demonstrated live network speeds of 450 Mbps with LTE Advanced Carrier Aggregation technology. While this falls well short of "hundreds of times faster" than 4G speeds that Samsung is aiming for with "5G" technology, Telstra's lab test speeds are reportedly three times faster than the 150 Mbps speeds other 4G networks in Australia claim as their theoretical maximums, or a whopping 8,000 times faster than the old fashioned 56 Kbps modems we all used around 15 years ago.
Telstra worked with Ericsson to aggregate two new 4G Frequency Division Duplexing (FDD) channels of 20 MHz bandwidth, each on the 2600 MHz spectrum band, with existing 20 MHz 4G on the 1800 MHz band. A prototype engineering device was used to create "three simultaneous side-by-side paths for the data to travel through to the operational core network."
Unfortunately, for Australian readers anyway, Telstra says that "deployment to customers remains a few years away" and that the "typical speeds achievable at a commercial level will be lower in practice."
Telstra notes that the tests show it can "carry a huge amount of future traffic demand shared across many users" – something telcos in other countries are sure to be eying with interest, presumably with the intent to replicate and even better the 450 Mbps speeds achieved.
Source: Telstra
With LTE-A it looks like it's capable of up to 8x8 MIMO and 128 QAM (downlink direction) with a theoretical max of 100 MHz and 3.3 Gbit/peak. In this test they were at 150 Mb/s per 20 MHz channel. In order to hit the numbers in the wikipedia example for theoretical max they would have been at ~660 Mb/s per 20MHz which seems high even for 128 QAM.
Their 150Mb/s per 20 Mhz is still double the theoretical max seen on LTE and its in the ballpark of where cable DOCSIS systems are with QAM 256.
I don't know how commonly they have to stitch more than 4 carrier frequencies together but without needing to buy more spectrum they might be able to hit 2x existing speeds with the new tech. I'm getting 40 Mb/s down on 4G now which is impressive, I'm slower (10Mb/s) if I connect to WiFi over my cable modem.
One of the big differences is while wireless carriers are throwing billions at any sliver of spectrum they can get their hands on cable companies are all like "We could channel bond a couple more 6 MHz channels but we have to keep 700 club and Garbage Delivery TV in our lineup". The next DOCSIS spec is supposed to allow up to 4096-QAM so they can boost speeds without anyone having to go without Garbage Delivery TV.