This chapter provided a brief introduction to wireless networks and technology. Wireless networks today are primarily based on either TDMA or CDMA technology. Second-generation networks support voice as the main application. However, in recent years, the use of SMS has taken off on a large scale and hence SMS as a data service is becoming synonymous with these networks. It is expected that third-generation networks will offer even greater bandwdith for data applications. While third-generation networks will enhance the capacity for carrying voice, they will also be driven by the need and support for data applications.