A standard-based approach for FMC SO that the industry can get a baseline to start with and to achieve economies of scale. 11.9.1 Network Convergence Currently two technologies are widely discussed in the context of FMC, namely Unlicensed Mobile Alliance (UMA) and IMS-based FMC. 11.9.1.1 UMA based FMC The UMA effort was initiated in January 2004 by a large number of operators and vendors with the purpose of materializing Fixed Mobile Convergence. The goal was to extend GSM/GPRS voice and data services over unlicensed spectrum technologies like Bluetooth and WLAN. UMA specifications were originally developed by Alcatel, AT&T Wireless, British Telecom, Cingular, Ericsson, Kineto E2E Network Architecture and Mobility Management HPLMN/PLMN Generic Access Network Controller Generic IP (GANC) Access Network D'/Gr' AAA Proxy/ Server Mobile Station GAN Controller SEGW Security Gateway Out of Scope HPLMN (roaming case) Figure 11.14 GAN functional architecture. Reproduced with permission from © 2007 3GPP [17] Wireless, Motorola, Nokia, Nortel, O2, Research-in-Motion, Rogers Wireless, Siemens, Sony-Ericsson and T-Mobile US. Later UMA was incorporated into 3GPP under the name of Generic Access (GA) to A/Gb interfaces in April 2005. The GA Network (GAN) was specified in 3GPP TS 43.318 and is part of 3GPP Release 6. Since then UMA industry group has halted its operations as an independent organization and continued their work on this within the framework of 3GPP. Generic Access (GA) is a complement to traditional GSM/GPRS/UTRAN radio coverage. 11.9.1.1.1 UMA Architecture Figure 11.14 illustrates a GAN architecture showing the main functional blocks. The key features of this architecture are [17]: Two new entities, namely dual mode (GSM and WLAN) mobile stations and GANC. Generic Access Network Controller (GANC) appears in the core network as GERAN Base Station Subsystem It includes a Security Gateway (SEGW) that terminates secure remote access tunnels from the MS and provides mutual authentication, encryption and data integrit