What is the difference between 1G, 2G, 3G and 4G and their Speed

1G known as First Generation Technology. In this First Generation Technology Radio signal is used. These are the analog technology for the communication and were introduced in 1980. 1G network were designed for voice calls and send text messages with no consideration of data services. The first 1G network was launched
by NTT- Nippon Telegraph and Telephone in Japan become the first 1 Generation Network. The disadvantages of 1G is noise come during communication. 1G operating on 800MHz band and works on FDMA- Frequency Division Mulitple Access.

2G (GSM)known as Second Generation Technology. 2G commercially launched in 1991 in Finland. Benefits of 2G Networks are provide the services as text message, MMS-Multi Media Message and Picture messages. Radio signals on 2G Network are digital. 2G improved sound quality and remove Noise during communication. 2G Operating on 900MHz – 1800MHz band and works on TDMA- Time Division Multiple Access. 2G network were designed for Voice services and slow data transmission.

2.5G (GPRS) are the enhaced version of 2G networks. In this GPRS- General Packet Radio Services introduced. 2.5G is intermediary between 2G and 3G and it provide speed upto 144kbit/s. 2.5G use Packet data instead of Circuit data.

2.75G(EDGE) use Enhanced Data rates for GSM Evolution. It allow improved data transmission rates.

3G known as 3^rd Generation Technology. The First 3G Network launch in Japan in 2001 by NTT DoCoMo. 3G Network have more data transmission speed compared to 2G Networks. The speed of data transmission on a 3G Network  is 2Mbit/s minimum for stationary and 384kbit/s in a moving vehicle. It means you can do video calling, Video Confrencing, Online Mobile TV, Mobile Internet Access, view High Definition Videos and much more.  

4G known as 4^th Generation Techonolgy. 4G Network provides High data rates because it have advance signal processor, new modulation OFDM- Orthogonal Frequency Division Multiplexing used. The 4G Network have two standard

• The Mobile WiMAX  
•  LTE- Long Term Evolution

Generation	Symbol	Standard Name	Speed
2.5G	G	GPRS- General Packet Radio Service	35 kbit/s - 171 kbit/s
2.75G	E	EDGE- Enhanced Data Rates for GSM Evolution	120 kbit/s - 384 kbit/s
3G	3G	UMTS- Universal Mobile Telecommunication Systems	384 kbit/s - 2 Mbit/s
3G	H	HSPA- High Speed Packet Access	600 kbit/s - 10 Mbit/s
3G	H+	HSPA+	2 Mbit/s - 20 Mbit/s
4G	4G	WiMAX- Worldwide Interoperability for Microwave Access	2 Mbit/s - 40 Mbit/s
4G	4G	LTE - Long Term Evolution	2 Mbit/s - 50 Mbit/s