4G vs 5G

The UK has just launched its first 5G network. EE has today rolled out 5G in a number of major cities: London, Manchester, Birmingham, Cardiff, Edinburgh and Belfast. But what is the real difference between 5G and 4G, which we all currently have on our phones.

Firstly, the marketing spiel, 5G is the next evolution and will be even faster than 4G. It will provide better support for small cells in urban environments and it will have lower latency.

But what about at the technical level? 4G uses a technology called LTE, there is also an improvement on this technology called LTE-Advanced or LTE-A, this is often branded as 4G+. Finally 5G uses a technology called “5G New Radio” or “5G NR”

Let’s firstly look at speed. Speed is equal to the bandwidth multiplied by the spectral density multiplied by the number of channels. Its the same formula for wired and wireless connections: here is a diagram showing ethernet over twisted pair

Comparison of twisted pair based ethernet technologies

You can increase speed (equivalent to the volume in the diagram) by increasing any of the three parameters.

Parameter4G (LTE)4G+ (LTE-A)5G (5G NR)
Max bandwidth20MHz40MHz400MHz
Spectral density4.5b/Hz4.5b/Hz6b/Hz
Number of channels244
Max theoretical speed180Mb/s720Mb/s9600Mb/s

As you can see, the maximum theoretical speed of 5G is many times greater than that of 4G and 4G+.

What about in the real world? Well EE has launched with only 40MHz of bandwidth. Spectral density will rarely go above 4b/Hz in a real world environment but all 5G phones support 4 channels (if signal strength is good enough). This means speeds of 640Mb/s is about as much as you can reasonably expect (and this ties in with what journalists have found)

So can you get just as fast speed with 4G+? Well possibly, EE also supports up to 40MHz of 4G+ bandwidth for up to 4 channels and spectral density should be fairly similar. The two reasons why journalists aren’t getting high speed 4G+ but are getting high speed 5G is because more devices are connected to the 4G+ network than the 5G network and the connection to the base station is upgraded from a 1Gb/s connection for 4G+ to a 10Gb/s connection for 5G.

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