Evolution of wireless communication system
Wireless access technologies have followed different evolutionary paths aimed at unified target performance and efficiency in high mobile environment. The first generation (1G) has fulfilled the basic mobile voice, while the second generation (2G) has introduced capacity and coverage. This is followed by the third generation (3G), which has quest for data at higher speeds.
1G: First Generation Networks:
- First generation cellular and cordless telephone networks are based on analog technology.
- All first generation cellular systems use FM modulation, and cordless telephones use a single base station to communicate with a single portable terminal.
- First generation wireless systems provide analog speech and in efficient, low-rate, data transmission between the base station and the mobile user
- Example of 1G is Advanced Mobile Phone Services (AMPS) TACS.
- In first generation cellular systems, common signaling channels were not used, and signaling data was sent on the same trunked channel as the voice user.
2G: Second Generation Networks:
- Second-generation (2G) mobile systems were introduced in the end of 1980s. Second generation wireless systems employ digital modulation and advanced call processing capabilities
- Examples of second generation wireless
- Global System for Mobile (GSM),
- TDMA and CDMA U.S.digital standards ( IS-54 and 15-95standards),
- Second Generation Cordless Telephone (CT2)
- Personal Access Communications System (PACS)
- Digital European Cordless Telephone (DECT)
- All second generation systems use digital voice coding and digital modulation.
- Second generation wireless networks have been specifically designed to provide paging, and other data services such as facsimile and high-data rate network access.
- In second generation wireless networks, the handoff process is mobile-controlled and is known as mobile assisted handoff (MAHO).
- The mobile units in these networks perform several other functions not performed by first generation subscriber units, such as received power reporting, adjacent base station scanning, data encoding, and encryption
- Second generation systems have been designed to reduce the computational and switching burden at the base station or MSCs.
- It provide more flexibility in the channel allocation scheme
3G: Third Generation Networks:
- The aim of third generation wireless networks is to provide a single set of standards that can meet a wide range of wireless applications and provide universal access throughout the world.
- Third generation systems will use the Broadband Integrated Services Digital Network (B-ISDN) to provide access to information networks, such as the Internet and other public and private databases.
Examples of Third Generation Wireless.
- Personal Communication System (PCS)
- Personal Communication Network (PCN)
- Third generation networks will carry many types of information (voice, data, and video),
- 3G network will operate in varied regions (dense or sparsely populated regions), and
- 3G Network will serve both stationary users and vehicular users traveling at high speeds