Mobile Networks Genrations:-

 

mobile-network-genration

The first generation (1G) mobile network developed in the USA was the AMPS network (Advanced Mobile Phone System). It was based on FDM (Frequency Division Multiplexing). A data service was then added on the telephone network, which is the CDPD (Cellular Digital Packet Data) network. It uses TDM (Time Division Multiplexing). The network could offer a rate of 19.2 kbps and exploit periods of inactivity of traditional voice channels to carry data. 

The second generation (2G) mobile network is mainly GSM (Global System for Mobile Communications). It was first introduced in Europe and then in the rest of the world. Another second-generation network is the PCS (Personal Communications Service) network or IS-136 and IS-95; PCS was developed in the USA. The IS-136 standard uses TDMA (Time Division Multiple Access) while the IS-95 standard uses CDMA (Code Division Multiple Access) in order to share the radio resource. The GSM and PCS IS-136 employ dedicated channels for data transmission.

The ITU (International Telecommunication Union) has developed a set of standards for a third generation (3G) mobile telecommunications system under the IMT-2000 (International Mobile Telecommunication-2000) in order to create a global network. They are scheduled to operate in the frequency band around 2 GHz and offer data transmission rates up to 2 Mbps. In Europe, the ETSI (European Telecommunications Standards Institute) has standardized UMTS (Universal Mobile Telecommunications Systems) as the 3G network.

4G is the short name for fourth-generation wireless, the stage of broadband mobile
communications that will supercede the third generation (3G ).According to the ITU,
a 4G network requires a mobile device to be able to exchange data at 100 Mbit/sec. A
3G network, on the other hand, can offer data speeds as slow as 3.84 Mbit/sec

The figure gives an idea of evolving standards of cellular networks. Despite their diversity, their goal has always been the same; to build a network capable of carrying both voice and data respecting the QoS, security and above all reducing the cost for the user as well as for the operator.