The previous two chapters described how wireless service providers can add value to their services by providing end-to-end service levels to their customers. In general, the wireless services of interest here are the basic voice and data services and, in particular, VoIP using WiFi and 3G networks. These VoIP services use the same underlying network infrastructure as used by the wireless data network, plus added wireless-VoIP-specific components. The wireless data network itself is an overlay network over a wireless circuit-switched network.

This chapter reviews the basic radio technologies of WiFi or wireless LAN (WLAN) and 3G mobile networks. Here the focus is on networking and basic voice and data services capabilities and their architectures, using both standalone WiFi, and 3G and in integrated WiFi and 3G network environments. We briefly describe basic circuit-switched voice service and an example of data service WAP Internet access over GPRS. We also describe integrated services between WiFi hotspots and 3G networks and consider user roaming and terminal mobility.

This chapter provides the necessary background on WiFi and 3G networking and their interworking, network domains, network elements, and roaming, which will help explain further details in building service models and voice over WiFi and 3G services networking and architectures. In Chapter 5, the WAP over GPRS service is used to explain the fundamentals of building service models. Chapter 6 describes VoWiFi/3G services networking and architectures built on the WiFi and 3G networking architectures.