Mobile Telecommunication Generations

0G, 1G, 2G, 3G, 4G, and by Year 2020 5G refers to the various generations of Mobile Phone Communication Technology Standards.

0G refers to the Mobile Radio Telephone Systems, Sometimes retroactively referred to as Pre Cellular or Zero Generation Systems. This systems included the Push to Talk (PTT or manual).
For Example Walkie-Talkies (2 Way Radio Telephone)

1G refers to the First Generation of Wireless Mobile Technology, which used Analog Radio Signals.
1G speeds vary between 28kbit/s & 56kbit/s, which means actual download speeds of 2.9KBytes/s to 5.6KBytes/s.

2G refers to the Second Generation of Wireless Mobile Technology, which uses Digital Radio Signals.
2G cellular Telecom Networks are commercially operated on the GSM & CDMA standards, commonly operated on the GSM-CDMA 850 / 900 / 1800 / 1900 MHz bandwidth.
2G provide services such as SMS (Text & Picture Messages) & MMS ( Multi Media Messages).
2G networks were built mainly for voice services and slow data transmission, Data rates vary between 56 kbit/s up to 72 kbit/s

2.5G (GPRS) .. GPRS could provide data rates from 56 kbit/s up to 115 kbit/s, it can be used for WAP, SMS & MMS services as well as Internet access.

2.75G (EDGE) .. EDGE could provide data rates upto 200 kbit/s

3G refers to the Third Generation of Mobile Telecommunications Technology, which provides data transfer rate of at least 200 kbit/s to 1 Mbit/s to Smartphones, Mobile Modems(Dongles) in Laptop Computers.
3G finds application in wireless voice telephony (VoIP), mobile Internet access, fixed wireless Internet access, video calls and mobile TV.
3G Radio Interface is called W-CDMA, commonly operated on the HSDPA 850, 900, 1900, 2100 MHz bandwidth.
The latest UMTS release, HSPA+, can provide peak data speeds of upto 56 Mbit/s in the downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the uplink.

Applications of 3G,
3G devices gives rise to applications not previously available to mobile phone users. Some of the applications are:

Mobile TV
Video on demand
Video Conferencing
Telemedicine
Location-based services
Global Positioning System (GPS)

4G refers to the Fourth Generation of Mobile Telecommunications Technology, which provides mobile ultra-broadband Internet access,For example to laptops with USB wireless modems, to smartphones & to other mobile devices.
Applications of 4G

Amended mobile web access,
IP telephony,
Gaming services,
High-definition mobile TV,
Video conferencing,
3D television
Cloud Computing.

Two 4G candidate systems are commercially deployed:
the Mobile WiMAX standard (at first in South Korea in 2006) & Long Term Evolution (LTE) standard (at sCANDINAVIA in 2009).
Data speeds of

WiMAX // Peak download 128 Mbit/s // Peak upload 56 Mbit/s
LTE // Peak download 100 Mbit/s // Peak upload 50 Mbit/s
LTE Advanced // Peak download 1 Gbit/s // Peak upload 500 Mbit/s

5G refers to the 5th generation mobile networks or 5th generation wireless systems.
Samsung has successfully tested its 5G network with 1 Gbps speed (potentially up to 10 Gbps) & aims to provide service by 2020.
In testing, the transfer speeds for the “5G” network sent data at 1.056 Gbps to a distance of up to 2 kilometers.[19][20]

The major difference from a user point of view between 4G & 5G techniques must be something else than increased maximum throughput;
for example lower battery consumption, lower outage probability (better coverage), high bit rates in larger portions of the coverage area, cheaper traffic fees due to low infrastructure deployment costs, or higher aggregate capacity for many simultaneous users

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