During the past year, mobile and integrated fixed/mobile operators announced an increasing number of fixed-mobile convergence initiatives, many of which are materializing in 2006. The majority of these initiatives are focused around UMA, the first standardized technology enabling seamless handover between mobile radio networks and WLANs. Clearly, in one way or another, UMA is a key agenda item for many operators.
Operators are looking at UMA to address the indoor voice market (i.e. accelerate or control fixed-to-mobile substitution) as well as to enhance the performance of mobile services indoors. Furthermore, these operators are looking at UMA as a means to fend off the growing threat from new Voice-over-IP (VoIP) operators.
However, when evaluating a new 3GPP standard like UMA, many operators ask themselves how well it fits with other network evolution initiatives, including:
o Soft MSCs
o IMS Data Services
o IMS Telephony
This whitepaper aims to clarify the position of UMA in relation to these other strategic initiatives. For a more comprehensive introduction to the UMA opportunity, refer to "The
UMA Opportunity," available on the Kineto web site (Kineto Wireless | The UMA Company).
Mobile Network Reference Model
To best understand the role UMA plays in mobile network evolution, it is helpful to first
introduce a reference model for today's mobile networks. Figure 1 provides a simplified
model for the majority of 3GPP-based mobile networks currently in deployment. Based
on Release 99, they typically consist of the following:
o GSM/GPRS/EDGE Radio Access Network (GERAN): In mature mobile markets, the
GERAN typically provides good cellular coverage throughout an operator's service
territory and is optimized for the delivery of high-quality circuit-based voice services.
While capable of delivering mobile data (packet) services, GERAN data throughput is
typically under 80Kbps and network usage cost is high.
o Circuit Core/Services: The core circuit network provides the services responsible for the vast majority of mobile revenues today. The circuit core consists of legacy Serving and Gateway Mobile Switching Centers (MSCs) providing mainstream mobile telephony services as well as a number of systems supporting the delivery of other circuit-based services including SMS, voice mail and ring tones.
o Packet Core/Services: The core packet network is responsible for providing mobile data services. The packet core consists of GPRS infrastructure (SGSNs and GGSNs) as well as a number of systems supporting the delivery of packet-based services including WAP and MMS.
Introducing UMA into Mobile Networks
For mobile and integrated operators, adding UMA to existing networks is not a major undertaking. UMA essentially defines a new radio access network (RAN), the UMA access network. Like GSM/GPRS/EDGE (GERAN) and UMTS (UTRAN) RANs, a UMA access network (UMAN) leverages well-defined, standard interfaces into an operator's existing circuit and packet core networks for service delivery. However, unlike GSM or UMTS RANs, which utilize expensive private backhaul circuits as well as costly base stations and licensed spectrum for wireless coverage, a UMAN enables operators to leverage their subscribers' existing broadband access connections for backhaul as well as inexpensive WLAN access points and unlicensed spectrum for wireless coverage.