How Mobile Broadband Works
- Only the tip of the iceberg is actually 'wireless'
- How to get around line-of-sight issues in cities
- Where does your data go?
A big dream for the writers here at Compare Broadband (and at our sister site, Compare Mobile Plans) is to successfully visualize just what’s involved in delivering your internet connection. One of the hardest concepts to visualize is just how your data is sent over mobile broadband.
Fixed Line broadband (such as ADSL2+, Cable and Fibre) are pretty simple to understand. Obviously the technology is fiendishly complicated, but the underlying principle is familiar – at one end, a signal is sent down a line made of either copper or glass, and travels along several lines joined together until it ends at your computer. It seems unevolved from the days of the telegraph.
Mobile Broadband isn’t terribly different – it’s just that one of ‘joins’ along the way is over the air, from a big tower to a small receiver, plugged into your computer. But seeing just how little of the mobile broadband network is actually ‘wireless’ can be surprising, and can serve as a reminder of just how real and ‘fixed’ our wireless networks are.
In lieu of our own videos that are proving difficult to organize (*cough* money *cough cough*), we offer an excellent summary from Gizmodo in the US, on how data is sent over Verizon's 4G network.
The video can be viewed by clicking here. For those checking this out at work, or on slower connections, here’s a walk-through (all images attributable to Gizmodo.com).
Note – the video and examples are specific to the Verizon network in the US, and to the use of Multimedia Messaging Services (MMS). The principles discussed, however, are relevant to the use of these services on Australian networks.
In the first image, the presenter has taken a short video of himself, and it opting to send it via Multimedia Messaging Service (MMS).
The data is sent to…somewhere dangerous, it seems. What’s being defended by these ominous looking signs?
A cell (or mobile) tower, of course. This enormous tower is bristling with several antennas, and is designed for a flat rural area (hence the height). Different antennas will handle different protocols (voice, 3G data, 4G data, etc) and different providers.
A cell site in a mountainous area (or, for that matter, an inner city site with buildings all over the place) might take the form of several small roof mounted antennas, to cover a much smaller radius. Here’s an example from the top of our own building in Armadale, Victoria, a heavy traffic area just outside the Melbourne CBD:
Back to the tower in the video. What’s feeding this behemoth? Like most things resembling a giant tree, we should find something that resembles giant roots! And so we find several coaxial leads, running down the inside of the tower, and terminating in a substation.
This is a full station – most towers would terminate in a cabinet with equipment to switch the signal back to a station. Here in Australia, telephone exchanges often serve as bases for the mobile network as well.
Aaaand…it gets complex from here. The leads carry into what’s basically a big server room, and we get closer to the high speed transfer links, the real freeways of the internet – the Fibre Optic links.
At the exchange, where all of this terminates for transfer back to the network, we have a full working plant room. This is serious business – these spots form the heart of Australia’s telecommunications networks. How serious? Much of the space here is taken up with banks of batteries, to provide backup in the event of a mains power failure. Oh, and a Diesel generator, in case the batteries fail.
From the site where the data is processed and sent along the airwaves, it’s then received at the tower closest to the recipient’s cell phone. And from there…to the phone itself.
Voila, right? This all happens millions of times a day…at the speed of light.
Sending email and pulling down webpages will be a little different. In those instances, the data will travel interstate, and then through a fibre optic lead under the ocean, to servers run by Google, or Amazon, or Apple…or dozens of others. Some information is ‘cached’ here in Australia, so it can load faster- but we’re talking a different of milliseconds here. It’s a whole different world.
So the next time you’re wondering why your message is failing to deliver, or why you can’t pull down your email, spare a thought for just how amazing it is that this stuff works at all!