1G-- Offers only call, no Tex, No Data
2G-- It Offers Data upto 250Kbps, Voice and Tex
3G-- It provides data speed at least 200Kbps upto 3Mbps
4G-- It provides 100Mbps for mobile access, And upto 1Gbps for wireless Acess
Most wireless carriers offering High Speed Packet Access (HSPA ) at up to 6Mbps are claiming that they offer 4G network.