Blog: Tech Guy - Generation next
- — 04 April, 2012 22:00
I've been to more demos of Long Term Evolution – the nonsensical name for the next generation of cellular broadband – than I can recall. The one I recall best was with Huawei in Shanghai: I got to go on the Maglev train to the airport and punt packets at 30Mbit/s while we zipped along at 430kph.
That was in 2010 and as far as I can tell, Chinese telcos have yet to launch LTE. The technology is cropping up elsewhere though, like the US and Canada. LTE is also tantalisingly close to New Zealand since last September’s launch of Telstra’s Australian 4G service. I got a chance to test drive it in February this year.
Telstra’s 4G isn’t a trial network, in other words. I wondered whether 4G would be able to deliver the high speeds I’d seen in my trials, once the real, live network was being used by an estimated 100,000 customers.
The first few tests in busy areas in Brisbane CBD showed 20Mbit/s downloads and just over 10Mbit/s uploads; nice, but I expected more. I found a good spot at Brisbane Airport and ran some tests using speedtest.net.
While the downstream speed (39–44Mbit/s) is impressive, it’s nice to see that Telstra has paid attention to the upstream which at 22Mbit/s is faster than my artificially-limited VDSL2 connection. I was watching Task Manager’s graph of the network throughput, and it was smooth without the peaks and troughs that indicate packet loss and ensuing TCP slowing. What’s more, the latency of the LTE connection is nice and low too.
In fact, the speeds I saw exceeded Telstra’s claimed “typical speeds” of 2–40Mbit/s down and 1–10Mbit/s up. They’re a long way off the theoretical maximum for this variety of LTE (100/50 Mbit/s) but even the ‘real life’ figures exceed what you get from most fixed broadband connections nevertheless.
Currently, there’s only a single device for the 4G service, the Sierra Wireless U320 USB modem. It costs A$299 on its own, or is bundled for free with Telstra’s two-year contract plans. The U320 is a chunky number, 50mm wide, 64mm long and 11mm thick. It’s equipped with two external aerial connectors, as well as a GPS and a MicroSD slot nobody will use.
The U320 is as big as it is because it supports not just 1.8GHz LTE, which Telstra uses for its service, but also 2.6GHz LTE and 850MHz/2.1GHz dual-channel and single-channel HSPA+ and HSPA. There’s a fair bit of electronics inside the modem, as well as aerials for the different frequency bands.
I was very happy with how tenaciously the U320 locked onto data signals. Roughly five kilometres away from CBDs and airports, the LTE signal disappears and you’re on Telstra’s NextG 3G service; where I was, the U320 ran in dual-channel mode, and gave me 15-20Mbit/s downloads, and 1.5-2.5Mbit/s uploads with 45-60ms latency. Again, very good considering this is a cellular service.
The LTE network itself was put in place by Ericsson for Telstra and the service uses 10 or 15MHz blocks configured as frequency-division duplexing (FDD), with separate bands for upstream and downstream data. LTE can also be configured as time-division duplexing. This sends and receives data in the same frequency band, which uses less spectrum. However, if you want the best performance and lowest latency, FDD is the way to go.
Telstra’s pricing is pretty good if you can tolerate the two-year contracts, starting at A$20 a month for 1GB of data going to $80 for 15GB. The data caps are about the only fault I can find with the service: based on my experience on speedy 4G, Telstra should multiply them all by ten. One gigabyte of data is ridiculously low and won’t last a day.
It would be great to get LTE, Telstra-style, in New Zealand too. However, our competition-loathing telcos aren’t likely to do anything until 700MHz spectrum is allocated to them with maybe some further subsidies on top.
LTE should also have been mandated for the Rural Broadband Initiative to ensure a service with a modicum of future-proofing. Sadly, despite clear evidence to the contrary, the government pretends LTE isn’t ready yet. For that reason, Vodafone built the RBI offering as a bung 5Mbit/s “peak speed” service with low 5GB data caps, using 3G gear.
To think what could’ve been, if the RBI had been designed with vision and foresight…