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What is 2G, 3G, and 4G? ** New Update 21st Sept 2015 **

by on ‎15-09-2012 20:17 - last edited on ‎31-10-2017 17:21 by (203,322 Views)

Smiley Happy


So when I originally wrote this, was many moons ago and I thought that since 4G has been here for a while then its time to update the information on here as well.


What is 2G, 3G, and 4G?

I've been on the forum now for many years and questions about the signal, frequency and the Network info are asked on many occasions. So I've written this to try and make it as understandable as possible.


What is meant by 2G, 3G and 4G?

2G stands for 2nd Generation Network, 3G is 3rd and you guessed it 4G is 4th Generation.


Other acronyms that you may have heard them being called are

2G = GSM           (Global System for Mobile)

3G = UMTS         (Universal Mobile Telecommunications System)

4G = LTE             (Long Term Evolution)


2G was introduced in the 90s in the UK and allowed us to use Text Messages (SMS), Picture messages (MMS) and Internet (WAP) all though it is rather slow.

Now if you look at your mobile phone / Smartphone. You may notice either a letter E, G or possible the circle on the iPhone.


For example, G stood for GPRS (Dial-up modem speeds. Real Slow Internet)

O2 – UK  o (Apple IOS 6.x and below), (Apple IOS 7.x and above now displays GPRS)

O2 – UK  G


E Stood for Enhanced, So you got a little faster Internet in theory!

O2 – UK  E


However, the 2G network was not fast enough for the consumer so 3G came about.

3G was introduced in around 2003 and brought us Video Calling and Faster Internet. Broadband speeds at the time, but again we wanted more.

So 3G started its upgrade path and was upgraded to the HSPA Family

HSPA = High-Speed Packet Access

There has been a few upgraded to the HSPA family and yes they are calls different names, but all they are is enhancements and faster speeds for us to use.

The latest upgrade going on is DC-HSPDA which is speeds of up to 42 Mbits (Megabits per second)


So you may see on your phone

O2 – 3G (On an iPhone's)

O2 – 3G or H or H+ (Other phones)

So if you see any of the above symbols, you know you're on a 3G Network (or 3rd Generation)


So then what is 4G.

4G is 4th Generation Network which will enable us to go even faster on our mobiles and mobile dongles. Possible speeds achievable are 1Gbit/s download and 500Mbit/s Upload. This is whats possible. However, the network has to support LTE-A and have the bandwidth to do the speeds mentioned. Also, your devices have to be able to support them as well. We are a long way at these speeds at present, but you never know what the future holds.


Going Forward...

The Devices themselves ie Mobiles are categorised. I.e. iPhone 6 and 6+ are Cat 4, so there max speed on LTE networks will never go any faster than 150Mbit/s down and Upload of 50Mbit/s.

Cat 6 Devices like Galaxy S6 and iPhone 6s and 6s+ can go to 300Mbit/s Down and 75Mbits Up.

However at present o2 network doesn't support Cat 6 just yet. (Please correct me if I'm wrong, but I've checked this recently and cant see Cat6 Listed for O2 Uk)

Cat 6 is also known as LTE-A (Long Term Evolution Advance)


4G can go faster with later Technology, but at present, the above is what can be achieved if the networks allow it.

The Max I've had downloaded on O2 was 67Mbs and upload was 32Mbps. on my iPhone 6+. Will try the same areas with I get the 6S+ shortly Smiley Happy


So why can some phones work on 4G, 3G and 2G,

Well, it's all to do with the frequency they are run on and your Receiver Microchip on your phone.

Is the way to explain is like a radio in the house or in the car?


There is FM, MW(AM), LW, SW (and others)

Some Radios can only pick up FM, MW(AM)

Some Radios pick up them all.


Mobile phones are no different, but they are called frequencies or Airwaves.


2G GSM have 4 bands in the world (For Mobile phones)

900 MHz used by O2 and Vodafone

1800 MHz used by Orange, T-mobile (Now EE), O2 and Vodafone

850 MHz, 1900 MHz bands are used in USA, Canada and some South American Countries only. (Also CDMA (Code division multiple access) which is another frequency completely different to GSM)


3G UMTS has 5 Bands that I used for Mobile phones

900 MHz is currently been used by O2 and Vodafone

2100 MHz is used by all the UK carriers

850 MHz, 1700 MHz and 1900 MHz are again bands that are used in USA, Canada and some South American Countries only. (And again enhanced CDMA (CDMA 2000) another difference to UMTS)


So why will 4G (LTE) be problems for manufacturers.

First problem is that 4G can be known as 4G or LTE (Long-Term Evolution).

2G and 3G had a set amount of frequencies that were utilised and that the mobile manufacturers were told they could only use. (It was Harmonised)


4G however hasn't had that sort of guidance and it become a free for all in the Mobile industry.

This is where the problem lies.

2G has 4 different bands, 3G has 5, 4G has 35+ frequencies and is still counting.

And this is causing issues.


UK is allowed to use 800 MHz, 1800 MHz and 2600 GHz. (1800 MHz used to be used for EE and O2 2G networks, but have been allowed to refarm some of the spare frequency for 4G)


800 MHz and 2600 GHz was sold by Ofcom in 2014. But not all operators bought 800 / 2600GHz Frequency.


O2 purchased 800 MHz and is obliged to provide 98% UK population indoor coverage by 2017 (O2 is now refarming spare 1800 Mhz it already owns from 2G to 4G (So the iPhone 5 that didnt used to work, now will when on a 4G 1800 Mhz frequency) London, Slough and other Cities are now using or tunring on 4G 1800 Mhz

Vodafone purchased 800 MHz and 2600 GHz

EE used spare 1800 MHz from 2G and purchased 800 MHZ and 2600 GHz

Three took 1800 MHz requested by Ofcom from EE (When T-Mobile and Orange Merged and had too much 1800Mhz band) and purchased 800 MHz as well


Also Note that the UK to France part of the Chanel Tunnel support 4G on O2, Voda and EE. All 1800Mhz Freq. 2G and 3G again on O2, Voda and EE.  No Three network at all though.


Now before you start to say, well some networks have more than others, It doesn't work like this. Each network purchased Chunks of the Frequency and some purchase more than others. Also Some are better chunks than other you can say as well


EE started 4G in October 2012

O2 and Vodafone Started 4G on August 2013

Three Started officially March 2014


Most of EU and Asia, are using 800 MHz, 1800 MHz and 2600 GHz, however you also have 850 MHz, 2300 MHz, 900 MHz for some parts of the world and again

Americas use a completely different frequency (700 Mhz 2 different bands, 2100 MHz, 1700 MHz and At&t are using 2300 MHz) and also use can use another different technologies completely (Again another different structure of frequency called Mobile WiMAX)


List of Networks on Wikipedia http://en.wikipedia.org/wiki/List_of_LTE_networks

Beleive me when I say its a Eye opener or confusion.


The iPhone 5 for the UK will use 2G and 3G on Vodafone only. (Update 4G will now work on O2 as long you are in a area with the 4G 1800 Mhz

So now O2, EE and Three will all support 4G on the iPhone 5 4G as we speak.

There is no mention that Vodafone are converting any spare 1800MHz into 4G


Note that the iPhone 5 in the EU utilises the 850 MHz, 1800 MHz and 2100 MHz frequency only.

iPhone 5 in USA utilises different frequencies as US networks are on different ones to us.

(To also make matters worse, US and some countries again chooses a different technology to LTE. They choose Mobile WiMAX)

iPhone 5S / 5C upwards are able to utilise all the 4G frequencies in the UK


Now you may have recently taking you phone to the USA and you don't have a LTE phone (4G), but noticed the phone may have said 4G? (More on the iPhone 4 and iPhone 4s)

Well you weren't really on 4G. Some American Networks says that there old 3G network is just as fast or nearly as fast as there 4G LTE network and therefore it should be called that. As there is no harmonised regarding 4G, this was agreed and so in the USA Some have named there old 3G to 4G (Due to the speeds and nothing else) So you can see its really confusing for customers.


To make Matters worse for example. 2600mhz is band 7 and 38. Even tho you phone may support 4g 2600mhz, it also has to support its band number as well.



So What was missing when they created 4G. You have heard me talking alot about Data speeds, well when they created 4G, they completely forgot about Phone calls (Yep what the Mobile was first made for)

So now they have had to create a new technology called VoLTE.

And if you guessed right, VoLTE stands for Voice over LTE (4G Network)


As the time of writing, VoLTE is currenlty supported on Three (Certian areas), Vodafone and EE will be before end of 2015 and O2 will be Q2 in 2016.


If you make a call now, you may have noticed that you phone will switch to 3G and 2G. (Good fun isnt it)

Also your phone has to also support VoLTE and again not all of them do.


Why can't mobile phones use them all. Technology, price and size of the Chip.

One day as new Micro Chips come out, we may be able to use more 4G networks, but until the time comes, we have to make do with what we have. At present the iPhone 6s and 6s+ support the most LTE networks in the world. but doesnt support them all.

Phones in the USA support there frequenices and again differ to those from EU and other areas in the world


I really hope the above is helpful and has been somewhat useful. I have tried to make it understandable as I know that the world of mobile phones is somewhat confusing.


 If you have any questions please ask and I will do my best to answer them.

on ‎15-09-2012 20:26
Well done Darren this is brilliant Smiley Happy
on ‎15-09-2012 20:52

Top job, worth a sticky Toby?

on ‎15-09-2012 20:58
I always like to discuss stickies with the other guys before I sticky them, but my initial thought is definitely. A great reference indeed!
‎15-09-2012 21:37 - edited ‎15-09-2012 21:41

Cheers all.


My first ever stickie Smiley Wink


Lets hope people find it useful.

by Anonymous
on ‎15-09-2012 22:16
Excellent post Darren, well done matey!
by Anonymous
‎16-09-2012 00:14 - edited ‎16-09-2012 08:09

very useful especially for iphone 5 people wanting to know about 4g

by Anonymous
on ‎16-09-2012 08:11
Well done Darren, great explanations!
by Anonymous
on ‎16-09-2012 08:24
Moved it, stickied it and kudoed it. Nice one, Darren.
by Anonymous
‎17-09-2012 11:32 - edited ‎17-09-2012 11:36

This is a great article, but I'm sure it will help people decide to move away from O2, especialliy if they are potential iPhone 5 purchasers, and to be honest I'm thinking about it. I've been with what is now O2 since the Jenie network, but I don't see why I should pay the same for a contract as it would be on EE and not be able to take full advantage of the 4G speeds on my new handset.


I don't get why O2 and Vodafone don't have enough spare frequency to start implementing 4G. As stated, 3G has been around for 9-10 years, so surely at this stage in the technological evolution most, if not all, of the network should be using 3G with 2G only existing as a back-up?


I'd like to hear from someone from O2 as to when they will be rolling out 4G as they must surely have a strategy in place now?

on ‎17-09-2012 12:23
In my opinion a sticky should contain just the info in the OP and be locked without the need for inane drivel to be tagged onto it... It kinda detracts from the factual purpose of a sticky.....
by Anonymous
on ‎17-09-2012 23:02

OK - this all sounds really clever but I have come onto the forum as a Grandma who would just like some help if possible.


O2 having been talking to me this evening about 2G, 3G, etc. but I am lost in all this and really only want to be able to talk to family without signal dropping.


Would anyone be able to give me their thoughts if I explain the situation or should it be posted elsewhere?


Thank you.

on ‎17-09-2012 23:57

@Anonymous wrote:

OK - this all sounds really clever but I have come onto the forum as a Grandma who would just like some help if possible.


O2 having been talking to me this evening about 2G, 3G, etc. but I am lost in all this and really only want to be able to talk to family without signal dropping.


Would anyone be able to give me their thoughts if I explain the situation or should it be posted elsewhere?


Thank you.

Hi and welcome to the forum.


Give it a go as it can always be moved if needs be.

on ‎18-09-2012 07:20

just to link to a bit of background on o2 4g plans watch the video at the bottom and note the wording near the end http://www.o2.co.uk/network/future


Also note it is worded in the video the next big thing in "MOBILE DATA" so all the old bands still needed for voice etc.

on ‎18-09-2012 22:52

Yep 4G in uk is currenlty Data until next year when masts are upgraded to also allow allow Voice and other things. But this is a fair few months yet

by Anonymous
on ‎19-09-2012 12:09
Great guide Smiley Happy
‎19-09-2012 23:29 - edited ‎19-09-2012 23:51

Answer to your questions Darren_V8   Sorry its a late reply


Im affraid its not just as easy as you think.


Orange and T-Mobile both run on the 1800mhz frequency. When they were merged last year this created spare capicity in the 1800mhz spectrum as all of a sudden t mobile customers could use the orange spectrum and vice versa.

However some of that now spare spectrum had to be sold as a condition of them merging. This has now been sold to three, but they wont get hold of this until September 2013.


However Orange and t-Mobile aka now ee still have free 1800mhz ava to use. So they applied to Ofcom to be able to use some  2G 1800mhz and convert this to 4G 1800mhz which ofcome agree (Lots of legal first) and this is how ee is able to create a 4G network with out doing any bidding.


O2 and Vodafone however run mainly on the 900mhz frequency and only own small ammounts of 1800mhz which is a overlap to the 900mhz frequency.


O2 applied to Ofcome to convert spare 900mhz frequency to 3G 900 which ofcome agreeded and this is what o2 is currenlty roling out. Vodafone i beleive are doing the same. However 4G im affraid isnt apealing to work on the 900mhz frequency and i dont beleive that o2 and voda have any spare on 1800mhz.


What you also have to understand that when the uk does start to roll out its 4G services, All the networks will be running on 800mhz, 2600mhz as this is what most of the EU is running on.

Why are we then delayed. Well Old Analouge TV runs on what is going to be 4G frequencies, so theres one delay. Then im affraid the networks have sort of been at each other of the 4G freqencies.


However I totally understand why you would want to go out and try ee new super 4G network. But please bare this in mind. Its currenlty only in 4 Cities and and will be in 16 Major Cities by the end of the year. Im not disputing it wont be fast, but 4G for the UK is still in its early stages. Also only Data will be used on 4G until middle of next year as 4G cant deal with any calls etc.


Hope this helps and answer your questions, but if you have any more, let me know


More info on 3G and 4G http://community.o2.co.uk/t5/forums/editpage/board-id/1/message-id/26798/is-draft/false

by Anonymous
on ‎01-05-2014 08:12

A really excelent guideSmiley Happy

This Ofcom site, which may be a little out of date, will show you the phone masts in your area and gives their Cell ID number, power transmitted out, frequency bands used and modulation type:



My local site at Marlborough is as below:

Name of Operator  O2
Operator Site Ref.  187
Station Type   Macrocell
Height of Antenna  25 Metres
Frequency Range  900 MHz
Transmitter Power  20.42 dBW
Maximum licensed power  32 dBW
Type of Transmission  GSM

Name of Operator  O2
Operator Site Ref.  187
Station Type Macrocell
Height of Antenna  25 Metres
Frequency Range  1800 MHz
Transmitter Power  27.35 dBW
Maximum licensed power  32 dBW
Type of Transmission  GSM

Name of Operator  O2
Operator Site Ref.  187
Station Type Macrocell
Height of Antenna  25 Metres
Frequency Range  900 MHz
Transmitter Power  27.92 dBW
Maximum licensed power  32 dBW
Type of Transmission  UMTS

3G (UMTS) in many areas is provided over 900Mhz and not the usual 2.1GHz.  This 3G on the cheap is not supported by all phones.

900MHz band is also used to provide  voice over GSM - as there is a limited number of frequencies available I am guessing that  during peak periods 3G Data services are reduced to free up capacity for the more important core business of voice traffic.  Only just a theory at this stage.




by Anonymous
on ‎19-05-2014 17:28

Thanks for the great post darrengf.

You stated (in sept 2012) that 4g in the uk is currently data but will be upgraded to allow voice and other things. Has this happened now?


on ‎19-05-2014 17:30

ibzo no volte (voice over 4g) is still in testing stages

by Anonymous
on ‎19-05-2014 17:36

Thanks for the quick reply.

This may be a silly question, but if O2 and vodafone both run on 800Mhz for 2G and 3G, is there a reason why I get great indoor signal with vodafone but not so much with O2?

Is there something I'm missing?



on ‎19-05-2014 17:40

They each have there own frequency allocation and mast locations so unless they both have a mast at the same location it will vary (900mhz 2g and 3g)

by Anonymous
on ‎19-05-2014 18:04
Just to confirm two points here.
1. O2 DO prioritise voice over data so in areas where capacity is struggling calls will take precedence.
2. The issue ISN'T always signal. Across the country o2 are having an issue with transmission. Effectively in many cases you make a call; that goes to the local mast, and then it goes into the fibre network to the mast it needs to get to in order to reach the recipient. Then it goes back over the air. That is the reason why Vodafone spent £1bn buying a fibre network in the UK.

In many cases your signal is fine. It is the lack of transmission that causes the issues.
by Anonymous
on ‎24-05-2014 22:55

In addition to all that stuff about frequencies, some of them were already in use as aircraft radio frequencies. Which has left some folks with a huge bill for replacing radios in light aircraft, totally uneccessarily. Just because folks operate aircraft does not mean they are rich

on ‎24-05-2014 23:00
Can you not just replace the crystals?
on ‎25-05-2014 03:02

Don't know

on ‎25-05-2014 10:23
From what I understand it is only some ground based radar that was affected and not any radio equipment running on the 800mhz freq as the bands given over to 4g were the old analogue tv bands.
Any radios on those freq would have been interfering with tv for years and prob illegal to use in uk anyway....
on ‎25-05-2014 17:59

I have attached the below link from a site i came across for a breakdown of what provider has what allocation of mobile frequency;




by Anonymous
on ‎21-06-2014 16:33

The Nokia Lumia 625 is advertised as being "4g ready"

What are the limitations of such a feature ?

on ‎21-06-2014 17:15

@Anonymous wrote:

The Nokia Lumia 625 is advertised as being "4g ready"

What are the limitations of such a feature ?

I'm not sure what you mean by limitations but the Lumia 625 can use 4G data with a suitable 4G SIM and 4G price plan. Voice calls drop back to 3G at present though.

on ‎21-06-2014 23:16
No limitations at all as long as you have the pre requisites in place and are in a 4G area it will receive a 4G signal.
by Anonymous
on ‎12-07-2014 10:11

I need a new SIM card fvor my phone.  Can you help me?

on ‎12-07-2014 10:44


Try this link https://www.o2.co.uk/freesim/


Hope that helps

on ‎12-07-2014 11:29

Alternatively, simply call in your nearest O2 store who will supply you with a new sim and swap your number and tariff over for you.

on ‎12-07-2014 12:22

@Anonymous wrote:

I need a new SIM card fvor my phone.  Can you help me?

or try any of the contact methods listed here http://www.o2.co.uk/contactus

Make sure you order the correct account type sim as PAYG and Pay Monthly are different sim cards.

on ‎12-07-2014 12:58

Not too bad then for my first help link attempt (Even though it took 10 minutes for me to find it) Smiley Very Happy

on ‎12-07-2014 13:09

@Cleoriff wrote:

Not too bad then for my first help link attempt (Even though it took 10 minutes for me to find it) Smiley Very Happy

Top job @Cleoriff Smiley Wink

by Anonymous
on ‎29-09-2014 23:41

How come when I went into the O2 shop in Inverness (83 miles away) to upgrade my phone, I was sold a 3/4G phone when I am in a 2G area? Now they say they will not change it , but the phone is not fit for purpose as I hardly get signal at all.  If I manage to get signal to call and then breath in or move a centimetre, I lose it.  I was also told by the girl in the shop that 2G phones cannot get internet, but this is rubbish because my husbands phone which he has had for about 5 years works well and gets better signal and internet than I do.  I feel that I have been mis-sold the phone I have now which is a Nokia Lumia 625 and am paying a fortune for a crap service.  I have also just read on the net that in 2017 they may be switching off 2G.  When are O2 going to update our masts in Caithness and the rest of the Highlands of Scotland? As you can guess I am not a techy but boy am I mad!

on ‎30-09-2014 08:35
You can set your phone to operate on 2g only, just have a look in your network settings. 2g won't be switched off, if at all, until all the network upgrades are complete which will give everyone a minimum of 2mbps 3g service.
by Anonymous
on ‎22-10-2014 12:32

I have a Blackberry with a Bolt-on which is worth the money when I'm in Switzerland or Germany because I can browse the web quickly but when at home I only get 2G which takes too long to load so I don't use it.  When will I get 3G, at least, in Dumfries and Galloway?

on ‎22-10-2014 12:36

Good question but one which we, as customers, can't answer I'm afraid. Just keep checking the status page for work on your local masts.

on ‎22-10-2014 12:49
The aforementioned status page is here http://status.o2.co.uk/
by Anonymous
on ‎30-10-2014 14:13

so, 2 years since the original post and 6 months since the update and still no 4G/LTE in Cardiff/south Wales?

Not even an estimated date? Only places I go where it's working is Manchester and London...

(Xperia Z1 compact - with 4G mini-sim..!)

this is very frustrating.

on ‎30-10-2014 14:16

Everyone shares your concern and crying out for a rollout schedule.

by Anonymous
on ‎25-11-2014 09:50
I would add that whilst 2G and 3G have recognise it's standards and are recognised technologies 4G is in fact still technically a draft standard and is a marketing term. It should be though of as 3.5G as true 4G needs VOLTE. And the lte standards are changing rapidly..

Either we will all have to refer to the new proper 4G when it's an agreed standard in the future of the iTunes will have to miss out the 4G standard completely and make a 5G one which means all current 4G phones are working to a draft and not finalised standard. That's why there are so many differences between handsets. Each is using its own take on what it thinks 4G should be. So unlike 3G handsets you need to delve into the technical details to see that the phone and your network are using the best match of technologies ( the point of proper standards is that this isn't necessary they all work to same set of rules)

by Anonymous
on ‎19-12-2014 21:31

Thats cool & very clear thanks, but when can we expect 4g in cornwall, recient mast builds & so-on have improved recption but mobile 4g would be helpful in an area where there is little or no wi.fi providers

on ‎19-12-2014 21:40
Unfortunately, O2 don't share that info with us....
by Anonymous
on ‎19-12-2014 22:10
The status check at status.o2.co.uk is now advising if the network modernisation programme will reach your area in the next 3 months. This is a recent improvement. Enter your postcode and if not in the current 3 months roll out keep checking back every so often for updates.
by Anonymous
on ‎27-12-2014 16:23
Thanks for the explanations, things are a little clearer now despite the continuing hiatus on battling for bands. At least I know now that I don't have to ditch my Nexus 4 just yet since I don't live in a 4G area. I'll sit tight and wait for bigger chips!!
on ‎31-08-2015 22:13

As it won't let me update my first post. Not sure why.  I wanted to give a update on 4G.


o2 4G will shortly be working on the 1800Mhz freq in London later this year, other cities will prob follow.  The 1800mhz freq is refarmed from 2G 1800Mhz that O2 own.


in the channel tunnel. 4G on O2 is 1800mhz and up and running fine.

on ‎31-08-2015 22:35

Hi @darrengf The only way your first posted can be updated now is if you ask @Toby to open it for a short period of time to allow for editing. That would be a good idea actually... as a new date would reflect how current your info is?...