LTE has been all over the news this year. It’s the evolution of mobile networks, and operators and consumers alike are excited for it to arrive. It is being slowly prepared for roll out all over the world – so why is a new standard called TD-LTE being touted before the old standard is even established? Don’t worry. If you don’t know your WiMAX from your WCDMA, then this is the article for you.
What’s the background here?
As mobile phones have been getting more complex, mobile network operators have hit an interesting problem. There are an increasing number of devices out there that can access the internet, stream music and videos, download and run always-connected applications, and more. The operators have discovered that even their data-enabled 3G networks just can’t stand up to the torrent of information that is now flowing across them. The infrastructure simply isn’t up to the task.
What’s the solution?
Network upgrades! The operators have been upgrading and updating their networks, but usually it only helps them stay barely abreast of their consumers. Networks like AT&T have complained about heavy data usage, and invested heavily in improving the existing networks. But you can only make a certain number of upgrades to existing 3G networks. Eventually, you need something bigger. So AT&T and others are looking ahead to the arrival of LTE as a saviour for mobile networks.
What is LTE?
It is the primary technology behind 4G – the evolution of 3G networks. Where 3G made mobile data a reality, 4G will make it a much better one. LTE stands for Long Term Evolution, and it lives up to its name. It has been in development for around 10 years now, and has begun to see some releases worldwide. The very first LTE network was launched by TeliaSonera in Norway and Sweden at the end of last year. But it is one very lonely 4G network, as most of the rest of the world is still at the trial stage. Boiled down to it’s basics, here is what LTE does:
• Much faster upload and download speeds than 3G. Under ideal conditions, LTE can easily reach download speeds of over 150 megabits per second, and upload speeds of over 80 megabits per second.
• More capacity than 3G – an LTE network can support more users in a single area
• Larger cell size. A single LTE cell tower can cover up to 100km. While that size will be greatly diminished in a heavy urban area, it’s still a lot better than 3G
• Compatability. LTE is designed to be compatible with existing standards
• Ease of upgrade. Part of the reason it has taken so long to develop LTE is that it is planning forward a lot. The networks are being designed so that implementing upgrades further down the line will be much easier.
So what’s TD-LTE?
TD-LTE has been gathering steam over the last few months, and now a lot of operators are experimenting with it. It stands for Time Division LTE, and was developed by China Mobile over the last three years. To keep this as simple as possible, here are the essential differences and similarities between TD-LTE and classic LTE:
• They run on different bands of the wireless spectrum. But the part of the spectrum that would carry the TD-LTE signal is much cheaper, and has much less traffic.
• TD-LTE and LTE are so similar that the same chip can access both networks – which is much easier for handset manufacturers.
• I mentioned the upload and download speeds of LTE above. On LTE networks, it carries two separate signals, one for data traveling in each direction. In TD-LTE, there is single channel, and it allocates upload or download bandwidth depending on what you’re doing.
• The other standard for 4G, WiMAX, is not particularly compatible with LTE. There’s talk that it WILL be compatible in the future, but it’s not at the moment. TD-LTE, however, can be pretty cheaply and easily upgraded to from WiMAX.
What we think?
While it seems crazy that new standards of LTE are being released before the old standards are even in place, it really does like TD-LTE might be going somewhere. There are tests being run in Western countries already, by companies like Ericsson. At the same time, China Mobile is pushing hard to gain better international recognition for the technology, and ZTE unveiled two TD-LTE base stations just earlier this week. Many operators are looking at the new standard, but it’s no guarantee we’ll be seeing TD-LTE any time soon.
The main thing that occurs to me here is that the shared channel for upload and download means that this will be better for mobile phones, but worse for computers. Having a shared upload-download signal means you can’t do both at once. If you’re downloading you can’t upload, and vice versa. But because the signal is larger overall, it means that WHEN you’re downloading it will run faster than on LTE. It seems unlikely you’ll be uploading AND downloading over your mobile at the same time, so TD seems like the best choice for smartphone owners. It might not work out so great for laptops and PCs, though.
So now we’re looking at two competing standards for LTE. They’re so similar that a single chip can access both of them. Not only that, but one is better for PCs and one is better for mobiles. And finally, TD-LTE gives WiMAX operators an option to switch to LTE without needing a ridiculously expensive rehaul. It looks like any operator that has the option to run both standards will have an unbeatable network for anyone who wants to connect to the web, over any device.
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