“…IMS can also be combined with both older legacy mobile data transmission technologies, such as GPRS, EDGE, EVDO, and UMTS, and with the more recent HSPA system, the emerging 3GPP LTE system [8]- [10], the WIMAX [11], [12], diverse WLANs [13] or even over satellite networks [14], [15], [31]. In a nutshell, IMS facilitates the transition from CS to PS communications and, hence, promises all the benefits of new powerful value-added services, as exemplified in [3], [16]- [30], [32], [78]- [83], and [85].…”