Cellular systems have come a long way since their introduction in the 1980s. The evolution progressed from First Generation (1G) systems to Second Generation (2G) systems. Now, Third Generation (3G) systems are being deployed.
1G systems introduced the cellular concept, in which multiple antenna sites are used to serve an area. The coverage of a single antenna site is called a cell. A cell can serve a certain number of users, and higher-system capacity can be achieved by creating more cells with smaller coverage areas. One distinguishing factor of 1G systems is that they make use of analog radio transmissions, so user information, such as voice, is never digitized. As such, they are best suited for voice communications, since data communications can be cumbersome.
The migration of 1G analog technologies toward 2G technologies began in the late 1980s and early 1990s. The primary motivation was increased system capacity. This was achieved by using more efficient digital radio techniques that enabled the transmission of digitized compressed speech signals. These digital radio techniques also supported data services with data rates as high as 14,400 bits per second (14.4 kbps) in some systems. 2G data communication is typically done using circuit-switched techniques, which are not very efficient for sending packet data such as that sent on the Internet. This inefficiency makes the use of wireless data more expensive f or the end user.
The next step in the evolution is from 2G to 3G, which started in the year 2000. The new key feature of 3G systems is the support of high-speed data services with data rates as high as 2 million bits per second (2 Mbps). Data can be transferred using packet-switching techniques rather than the circuit-switching approach. Therefore, it is more efficient and less expensive. This opens up the possibility of cost-effective Internet access, access to corporate intranets, and a host of multimedia services.
If you want to read more about the evolution of wireless networks and WCDMA radio networks in general, please stay tuned for the next several editions where I will go into details.
Upcoming including but not limited to:
- Physical layer functions
- W-CDMA Channels
- Basic call setups
- Data session setups
- Service reconfigurations
- UTRAN mobility management
- Inter-system procedures
- RF design & analysis of UMTS radio networks
- The evolution of UMTS
- Architectures