Optus has shown a live demo of high def video streaming over its trial 4G (LTE) mobile network in North Sydney.
It demoed an Long Term Evolution (LTE) base station streaming data at 43Mbit/s downstream and 800Kbit/s upstream to a notebook with an LTE USB dongle plugged in. With this throughput, the number two telco was also able to show glitch-free high definition video streaming over the connection.
Optus said in its own testing it had seen peak speeds of 73Mbit/s, and upload speeds of 20Mbit/s – though its upload speed in the live demo never reached anywhere near this.
The company is planning to put its LTE network on the 700MHz spectrum freed up by the gradual shutdown of analogue TV, which should provide in-building penetration as good as Telstra's Next G network. It will also run it on the much higher frequency 2.5GHz spectrum for high density areas with lots of users on streets.
It will run the LTE cells on 10MHz of radio bandwith, but says the LTE standard can go up to 20MHz, which would allow theoretical max speeds of up to 173Mbit/s.
Importantly, though, Optus says the network will also provide much better latency than the 3G network does – one of the key complaints about Optus' existing network over the last few years. Latency is the time it takes for a packet of data to be sent over the air and acknowledged back from the other end, and makes a big difference in the responsiveness of internet applications where many small pieces have to be loaded – such as web pages.
The LTE network architecture gets rid of the separate radio network controller (RNC) boxes in the network, as these are integrated into the base station software, which contributes to the lower latency.
However, the telco did not demonstrate the latency of LTE in its live demo.
APC Reader Mtats tweeted a question to us while we were at the press conference: "@APCmag Ask him if they are going to fix their 3g network before the try and reach for the stars with LTE."
We asked that question to Optus' director of engineering, Andrew Smith, and his response (see the video here) was: "the best response I can make to that is that we've made a significant amount of investment over the last few years in response to rising demand, and we believe through our own measurements and external measurements as well, that we've made some substantial improvements in quality. We've seen the average speeds improve, we've seen general customer satisfaction rates that we measure go up on the back of that. So we think we are generally improving, and in fact in the engineering sense we work on a continual improvement basis. We continue to look at … whether it's on the investment basis, or tweaking and improving the network, how we can improve the customer experience."
Smith said that Optus had been looking at the way different devices use the network, and 'tweaking and parameterising' the network accordingly. For example, on smartphones, Optus sees typical bursts of usage smaller than 150KB, and the number one site in terms of data transactions is Facebook, followed by Google. This is quite different to the data usage seen from 3G mobile broadband dongles.
Optus wouldn't comment on when exactly it would launch a commercial LTE network, but did say that it wouldn't do so until there were enough devices for end users -- mobile broadband dongles, tablets, phones and so on -- that had it built in.
It also made the point that LTE is not a separate network to 3G -- it will work in conjunction with 3G HSPA and 2G, with devices falling back to the best available signal in any area. It did point out that around 20 networks worldwide are expected to go live with commercial LTE services by the end of this year. However, Optus is still seeking certainty from the Australian Government on what spectrum it will be able to access in upcoming spectrum auctions.
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