In a nutshell the difference is SPEED. The G in 2G, 3G and 4G stands for Generation, and they refer 2nd, 3rd and 4th generation of wireless technology. The newer generation is faster, more secure and more reliable. 1G was offered in analog technology (AMPS), and since 2G signals are transmitted in digital format in GSM and CDMA technologies.
So, what are the speeds delivered in each of the 2G, 3G, 4G and 4G LTE technology?
1G – The analog 1G offered simple telephony service without data.
2G – Delivered digital signal and offered up to 250Kbps speed. Supports voice, text and data services.
3G – At least 200Kbps up to 3Mbps speed.
4G – 4G delivers up to 100Mbps for mobile access, and up to 1Gbps for wireless access. Most wireless carriers offering HSPA (High Speed Packet Access) at up to 6Mbps are claiming that they offer 4G network.
4G LTE – LTE (Long Term Evolution) is one of the two standards offered within 4G, and WiMax being the second one. The specification calls for downlink speed of up to 300Mbps and uplink speed of up to 75Mbps.
Currently, United States has a 4G LTE penetration rate of approximately 20%. As Verizon, AT&T, Sprint and T-Mobile build out more LTE coverage, we’ll experience true 4G speed in mobile networks.