MOBILE COMMUNICATIONS

Mobile communication is the application of wireless technology in the access network. It offers many useful features,

•    Easy installation for rapid roll out

•   Proven platform with scalability

•    Future proof

•    Reliable and secure

•    Mobility

It is a very rapidly growing and popular service which was revolutionised telecommunications. It has become a backbone for business success and efficiency. It connects subscribers to the public switched telephone network(PSTN) using radio signals as a substitute for copper.it allows any body to communicate with any one while on the move.

Different technologies emerged for different types of requirements-coverage, capacity, mobility, bandwidth.

GSM

CDMA

CORDECT

PHS

AMPS,DAMPS

EVOLUTIONS OF MOBILE COMMUNICATIONS:-

FIRST GENERATION(1G):ANALOG CELLULAR:-

The introduction to cellular systems in the late 1970s and early 1980s represented a quantum leap in mobile communication(especially in capacity and mobility). Semiconductor technology and microprocessors made smaller and lighter weight , and more sophisticated mobile systems a practical reality for many more users. These 1G cellular systems still transmit only analog voice information. The most prominent 1G systems are ANALOG MOBILE PHONE SYSTEM(AMPS), NORDIC MOBILE TELEPHONE(NMT) and TOTAL ACCESS COMMUNICATION SYSTEMS(TACS). With the 1G mobile introduction, the mobile market showed annual growth rates of 30 to 50 percent, rising to nearly 20 million subscribers by 1990.

SECOND GENERATION(2G):MOBILE DIGITAL SYSTEMS:-

The development of 2G cellular systems was driven by the need to improve transmission quality, system capacity and coverage. Further advances in semiconductor technology and microwave devices brought digital transmission to mobile communications.sppech transmission still dominates the airways,but the demands for fax,short message and data transmissions are growing rapidly. Supplementary services such as fraud prevention and encrypting of user data have become standard features that are compatible to those in fixed networks. 2G cellular systems include GSM, DIGITAL AMPS(D-AMPS),CDMA and PERSONAL DIGITAL COMMUNICATION. Today multiple 1G and 2G standards are used in world wide mobile communications. Different standards serve different applications with different levels of mobility, capability and service area standards are used only in one country or region and most are in compatible.

2G TO 3G GSM: EVOLUTION:-

Phase 1 of the standardization of GSM 900mhz band was completed by the EUROPEAN TELECOMMUNICATION STANDARD INSTITUTE (ETSI)  in 1990 and included all necessary definitions  for the GSM network operations. Several tele services and bearer services have been defined (including data transmission upto 9.6kbps), but only some very basic supplementary services offered. As a result, GSM standards were enhanced in phase 2 (1995) to incorporate a large variety of  supplementary services that were compatible to digital fixed network integrated services digital network(ISDN) standards. In 1996, ETSI decided to further enhance gsm in annual phase 2 + releases that incorporate 3G capabilities.

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