4G and LTE :Things To Know
What is 4G?
It decided that the peak download speeds for 4G should be 100Mbit/s for high mobility devices, such as when you're using a phone in a car or on a train.
When you're stationary, (low-mobility local wireless access) it decided that 4G should be able to deliver speeds up to around 1Gbit/s.
If true 4G is supposed to offer us download speeds of up to 1Gbit/s, then why are we getting 100x less in the UK, at around 10-12Mbit/s in real-world speeds?
Unfortunately the ITU-R doesn’t have control over the implementation of the standard, which led to first-generation technologies like LTE being criticised for not being up to scratch with true 4G. (We'll explain LTE in a minute.)
The reason for this is that other groups (3GPP being an example) that work with the technology companies who develop the hardware had already decided upon next-gen technologies, leaving us with sub-standard 4G capabilities.
What is LTE?
Though originally marketed as 4G technology, LTE (Long Term Evolution) didn't satisfy the technical requirements that the ITU-R outlined, meaning that many early tariffs sold as 4G weren't actually 4G.
However due to marketing pressures and the significant advancements that LTE brings to original 3G technologies, the ITU later decided that LTE could be called 4G technology.
So, LTE is a first-generation 4G technology that should theoretically reach speeds of around 100Mbit/s. Unfortunately, Ofcom reports that the UK average is around 15.1Mbit/s. While that's around twice the speed of an average 3G connection, it’s a long way off from the theoretical top speed of LTE.
As well as lacking in overall download speed, LTE also lacks uplink spectral efficiency and speed. Uplink spectral efficiency refers to the efficiency of the rate that data is uploaded and transmitted from your smartphone.
It falls short of the true 4G capacity mainly because of the lack of carrier aggregation and also phones not having many antennae. MIMO (Multiple Input Multiple Output) is a practical technique for sending and receiving more than one data signal on the same channel at the same time by using more than one antenna.
With better carrier aggregation (explained below) and MIMO, we can head towards a new standard: LTE Advanced. This is also known as 'true' 4G.
Imagine playing a PlayStation 3 when you could be playing a PlayStation 4. The PS3 isn’t necessarily too slow to use, but you’d have a better experience using the faster console, the PS4. It’s the same with LTE – LTE is the PlayStation 3 and LTE Advanced (LTE-A) is the PlayStation 4.
What is carrier aggregation: why it is important ?
Carrier aggregation is part of LTE-Advanced and lets operators treat multiple radio channels in different or the same frequency bands as if they were one, producing quicker speeds and enabling users to be able to perform bandwidth hogging activities like streaming HD video much faster than ever before.
Think of your wireless connection as a pipe. You can't increase the size of the pipe, but you can add a second and third pipe. Use all three simultaneously and you’ll have three times the flow rate. It’s the same concept with carrier aggregation.
Another advantage of carrier aggregation is that speeds don’t decrease, no matter how far away from the cell tower you are.
Combining two signals - or channels - should theoretically double the download speed to around 150Mbit/s. In future, there could be aggregation across more than two channels, potentially up to five, which was defined in the LTE Advanced standard.
Post a Comment