Dora The Explorer
Forum Guru
A G is a generation.
Within each of those generations there are various competingh standards, and various "half step" improvements.
Each of these is a different modulation scheme, a different protocol stack, different technology architecture, different radio. As a result each one is a complete new network & new modem although, of course, in practise those are combined into one multi-mode physical system.
There is also a lot of marketing spin.
UMTS is technically a broader term but is roughly a synonym for WCDMA = the most widespread form of 3G.
GSM can refer to just the 2G voice standard, or (more usually) the family of standards = GSM+GPRS+EDGE.
In USA the term is also used (confusingly) to include WCDMA 3G
Within each of those generations there are various competingh standards, and various "half step" improvements.
Each of these is a different modulation scheme, a different protocol stack, different technology architecture, different radio. As a result each one is a complete new network & new modem although, of course, in practise those are combined into one multi-mode physical system.
There is also a lot of marketing spin.
- 1G = analog
Examples include NMT, AMPS, TACS, etc
This did not do data. - 2G = digital, voice
Examples include GSM, D-AMPS, PDC
Those could do data but only as analog modem (using the whole channel) at 9.6Kbps
2.5G added dedicated digital data (GPRS)
2.75G faster data (EDGE)
Data rates from 9.6Kbps (GSM) to to 33Kbps (GPRS) 200Kbps or higher(2.75G) - 3G = digital, supported data, but still circuit switched
UMTS / WCDMA, EvDO
Includes data but still onto circuit switched architecture
3.5G faster data, added true always-on / packet data (HSPA)
Data rates of 2Mbps-tens of Mbps
NB The USA and few other places had a rival technology ("CDMA"). IS95, EvDO.
That was marketed as 3G when it was launched, but initially was probably closer to 2.5G and then upgraded to 3G with the EvDO upgraded. - 4G = wireless broadband
OFDMA, flat architecture, true packet switched
Pure data: voice as VoIP (VoLTE)
Most people say this is LTE & WiMAX, (though some people are waiting for an upgrade to LTE-A, based on a rather silly data rate definition).
4.5G term not widely used but some people say that is LTE-A
Data rates of Tens of Mbps - Hundreds of Mbps - 5G = not yet defined
Much faster. Likely to be real ~2020
Being argued about now in standards bodies.
Will likely be an extension of 4G but with higher data rates & better support for IoT
Data rates of “1Gbps” are proposed
UMTS is technically a broader term but is roughly a synonym for WCDMA = the most widespread form of 3G.
GSM can refer to just the 2G voice standard, or (more usually) the family of standards = GSM+GPRS+EDGE.
In USA the term is also used (confusingly) to include WCDMA 3G
