Technology generations in wireless telephony are know as 2G,3G and 4G.
Thanks to that technologies we can say "Look Ma': There is no wires! This is magic!"
But that's all? No!
The biggest difference between generations for users come in terms of data rates(speed) and also in terms of support for data services. That's why higher generations allows. users to do more with their wireless data.
But between 2G,3G and 4G are even more generations.
Let's see those one:
2.0G. = GSM
2.5G. = GPRS
2.75G = EDGE
3.0G = FOMA, 1xEVDO Rev. A, UMTS
3.5G = HSDPA
3.75G = HSUPA
WiMAX = 1st generation, MIMO/SOFDM
LTE = LTE Advanced
That's all for now, but those generation wich data rate offer?
EDVO Rev A (3G) can offer speeds of up to 2.4 Mbps for download and 153 Kbps for upload.
UMTS (3G) can offer speeds of up to 21 Mbps for download and 7.2 Mbps for upload
HSPDA (3G) can offer speeds of up to 42/82 Mbps for download
LTE (is 3G not 4G,on 4G is LTE Advanced ) can offer speeds of up to 100 Mbps for download and 50 Mbps for upload
WiMAX (4G) can offer speeds up to 20 Mbps of data rates but next version plans to allow 1 Gbps and beyond, check http://ieee802.org/16/
LTE Advanced (4G) can offer speeds up to 1 Gbps for download (Theorically)
Note, that these numbers are theorical(mainly 4G one xD maybe on 5G or 6G)
But its nice to know that some experts think that by year 2020 most people's primary means of internet access will be wireless fully established 4G networks.
Maybe on 2020 will be 5G or 6G :)
But i want that on my Android device xD
That's all folks.
Pd: For a better reference check DragonWave DWI-APP,171, June 2009 and Mobile Backhaul stuff