Telstra has announced plans to release upgraded 4G dongles and handsets that will offer theoretical speeds of up to 150Mbps. Yet the very large difference between the theoretical maximum and what users can actually expect to receive reminds us that however useful they are, mobile networks have inherent speed maximisation issues.
In a post on its Exchange blog yesterday, Telstra said it would release Cat 4 devices later this year (disappointingly, it doesn't mention Wi-Fi hotspots). Its current Cat 3 equipment has a theoretical maximum speed of 100Mbps for downloads. In practice, Telstra says customers typically experience speeds between 2Mbps and 40Mbps on those services. We've rarely seen sustained speeds at the later level, and the more people who sign up for 4G, the lower that likelihood becomes.
Cat 4 devices have a theoretical maximum download speed of 150Mbps. Telstra says its own tests in Perth and Esperance suggest a maximum throughput of 90Mbps. That's much faster than 40Mbps, but still represents only two-thirds of the potential maximum speed. Achieving that speed requires Telstra to have over 20MHz of continuous 4G spectrum available, which will not be the case in many of the areas where 4G is currently active.
The Telstra posts is refreshingly honest about the reality of mobile broadband, highlighting all those figures itself, noting all the other factors that can influence network performance and pointing out that once you reach a certain speed level, the number of sites you can access that will take advantage of that speed are fairly minimal. It also repeats a point we find ourselves constantly making at Lifehacker: speeds for mobile broadband depend on wired connections as well:
There is no point using the latest wireless technology if the tower or cell is not using a high bandwidth connection back into the core network. In the Telstra network over 93% of the population is served by a base station with 1Gigabit capable backhaul. These are currently configured at either more than 100 or 200 Mbps per site.
We'll certainly be testing out the new Cat 4 devices when they appear to see how the speed measures up in the real world. As ever, we'll expect improvements, but also a wide range of performance.
Telstra 4G network set to get faster [Telstra Exchange]