Fixed-Mobile-Convergence - Market Requirements

Fixed-Mobile-Convergence (FMC) refers to the converging of wireless (cellular) with Voice over IP. This typically refers to the use of a converged cellular phone that can operate using the standard cellular system as well as access voice over IP over WiFi (802.11) radio access.

For calls over the WiFi link, speech packets are sent over a broadband IP link to a media gateway that finally delivers the call to the PSTN or another mobile subscriber. The backhaul can occur over a broadband IP network: either over cable, wired DSL, optical, etc., which allows wireless, wireline and cable operators to offer an FMC service, with the necessary business relationships and network connections to package the solution.

Fixed Mobile Convergence - AudioCodes Solutions

AudioCodes supports three types of FMC solutions:

• Unlicensed Mobile Access ((UMA) for connection with GSM networks
• SIP-based FMC for connection with GSM or CDMA networks
• SIP-based Voice Call Continuity (VCC) within IMS networks

Unlicensed Mobile Access (UMA)

UMA (Unlicensed Mobile Access) provides a standardized method allowing dual mode phone users to access GSM cellular networks over WiFi. The UMA Controller and Media Gateway provide the same A-Interface to the MSC (Mobile Switching Center) as a GSM BSC (Base Station Controller), permitting UMA deployment with minimal impact to existing MSCs and more importantly, minimal impact to backend office billing systems. The handset utilizes GSM-based processes to initiate and terminate phone calls over the WiFi access network. The UMA Controller provides the software control to emulate the BSC and manage the WiFi subscribers. The AudioCodes’ UMA Media Gateway provides the termination of the AMR codec received over IP and connects the speech path to the MSC. Another component of the UMA system is AudioCodes’ Security Gateway which provides termination of IP-Sec (IP Security) tunnels with each mobile handset providing the required security over the potentially open WiFi / Broadband access. Connecting to the MSC authorizes subscribers to be authenticated for service, similar to the GSM system, enabling access to the same services available over the GSM access network. 

SIP-based FMC

SIP-based FMC approaches the connection to the cellular system by emulating another MSC. Either ANSI-41 messages for CDMA networks or GSM-MAP messages for GSM networks are used for subscriber authorizations as well as handoffs to existing cellular systems. In this case, the handset sends SIP messages to initiate & terminate calls by communicating with the FMC Controller. The Media Gateway terminates the GSM or CDMA codecs sent over IP and connects to either the PSTN or the cellular system.

Voice Call Continuity (VCC) - IMS

Similarly, VCC is based on SIP, but defines the FMC controller as an Application Server named Call Continuity Control Function (CCCF) within an IMS Core Network. This CCCF server performs a very similar function as that noted above in the SIP-based FMC, but utilizes the network elements within an IMS core network. CCCF handles all calls whether the call is initiated in the legacy cellular system or within the WiFi access network. This dictates that if a call is initiated in the legacy cellular network, the call is passed to the CCCF within the IMS core network for processing. The CCCF and the handset facilitate the handover process between the WiFi access network and the cellular network as needed during the course of a call. AudioCodes’ Media Gateways are used to terminate voice calls over the WiFi access network and connect them to either the PSTN or to the cellular system.

Summary

FMC’s convergence of wireless, wireline, cable and enterprise demand a highly flexible, robust media gateway in order to handle the multiple vocoders, signaling and control standards to accommodate the different network access and interworking requirements. AudioCodes’ support for UMTS, GSM, CDMA, Cable and VoIP vocoders, along with our high voice quality and signaling support provide for a robust Media Gateway platform ideally suited for a FMC application.