Overview of Wireless Networks and Technology

Wireless networks have been an essential part of communication in the last century. Early adopters of wireless technology primarily have been the military, emergency services, and law enforcement organizations. Scenes from World War II movies, for example, show soldiers equipped with wireless communication equipment being carried in backpacks and vehicles.

As society moves toward information centricity, the need to have information accessible at any time and anywhere (as well as being reachable anywhere) takes on a new dimension. With the rapid growth of mobile telephony and networks, the vision of a mobile information society (introduced by Nokia) is slowly becoming a reality. It is common to see people communicating via their mobile phones and devices. The era of the pay phones is past, and pay phones stand witness as a symbol of the way things were. With today's networks and coverage, it is possible for a user to have connectivity almost anywhere.

Growth in commercial wireless networks occurred primarily in the late 1980s and 1990s, and continues into the 2000s. The competitive nature of the wireless industry and the mass acceptance of wireless devices have caused costs associated with terminals and air time to come down significantly in the last 10 years. As a result, we now have penetration rates of mobile users reaching almost 100% in countries like Taiwan, Italy, and Finland. Subscriber growth has been increasing by leaps and bounds; by mid-2002, the number of subscribers already exceeded 1 billion. The exponential growth of mobile subscribers is shown in Figure 3-1.

Figure 3-1. Subscriber statistics source: EMC World Cellular Database.

The service offered on wireless networks today is primarily voice. However, the growth of data via short message services (over 24 billion messages per month, as per data in the Groupe Special Mobile [GSM] World Congress) in the last few years has been increasing rapidly. Wireless networks have evolved to the point today wherein there are two major technologies deployed today: the TDM-based GSM networks, and the CDMA-based networks. GSM networks account for about 70% of the wireless networks today. CDMA accounts for about 25% of the networks, and the other 5% are networks of other types, such as the PDC network in Japan. Many of the TDM-based IS-136 networks that were prevalent in the Americas are now transitioning to either GSM or CDMA. An example of this is the AT&T Wireless network in the U.S., which is currently rolling out a GSM/GPRS network to replace the IS-136 network; the same is the case with Cingular wireless.

The growth of wireless networks is expected to continue well into the first decade of the twenty-first century, and the number of wireless subscribers is expected to overtake the number of fixed lines within the next three years