Here are the theoretical Difference between various wireless internet access methods - GPRS / EDGE /3G and 4G
GPRS: refers to a service on the 2G network that provides basic data up to 56kbps (similar to dial-up speeds)
EDGE: It is a 2.5G technology. An enhancement of the 2G technology which provides higher data transfer rates compared to GPRS (the default on 2G).The speeds can go up to 144 Kbps
3G: 3G technology provides faster / higher data transfer rates compared to the 2G network (EDGE & GPRS).This technology can offer speeds up to 21 Mbps
4G: This technology rides on LTE platform and is the latest in the world of mobile data transfer. It is the next generation of mobile communications. Currently it is the most advanced technology available. Theoretical data downlink speeds can go up to 100 Mbps.