UMA SUPPoRTS THE UMTS coRE
nETWoRK InTERFAcES Another question
asked by operators is whether there is a need for
3G Iu interface support within the 3GPP UMA
standard. As mentioned above, Iu interface support
is not required to accommodate handover between
UMA and UMTS networks. Moreover, operators
with UMTS networks can support 3G services today
through UMA using the existing A and Gb
interfaces.
However, since there are several UMTS-only
operators, and operators with combined GSM/
UMTS networks looking to migrate more traffic
to their 3G SGSNs and MSCs, it is logical for the
UMA standard to evolve to incorporate Iu interface
support. As expected, such a standardization effort
is already in process and supported by major mobile
operators and vendors.
DEPLoYMEnT
MSC-Server (MSS) to handle call control and a Media
Gateway (MGW) to switch user-plane traffic. Several
reasons for operators to implement SoftMSCs are
transmission cost savings, as well as much lower cost
voice-switching capacity. For example, the distribution
of MGWs to radio network concentration points enables
local switching of mobile-to-mobile calls and local
breakout to the PSTN. Release 4 MSCs are also a critical
step in enabling the transition of today's circuit-switched
domain to IP-based, next-generation networks.
impact between the solutions. However, it is expected that
UMA deployments will add significant minutes of use
into the mobile core network, therefore growing that voice
capacity on new SoftMSCs versus the existing MSCs may
result in significant capital savings.
SERVIcES oVER WI-FI
Subsystem (IMS) architecture introduces a new platform
new IP-based multimedia services including Presence,
Push-to-Talk over Cellular (PoC), Video Conferencing
and Interactive Gaming. By definition, IMS is a service
layer technology and is dependant on various packet-
based access layer technologies to enable subscriber
access to services.
GPRS/EDGE and/or UMTS radio access networks. As a
packet-based radio access layer technology, like GERAN
and UTRAN, UMA is entirely complementary to IMS.
broadband IP access networks. With UMA, any IMS service
available to a subscriber on the macro cellular network can
be accessed over a broadband IP access connection. UMA
enables access to IMS services from any WLAN location
and manages the automatic handover of IMS sessions
between the cellular network and WLAN, and vice-versa.
IMS TELEPHonY
service to an IMS infrastructure in the near to mid-term,
they will eventually make that transition. Since UMA
provides seamless mobility for circuit, packet and IMS-
based services, it also enables access to, and mobility
of, IMS telephony services between cellular and Wi-Fi
networks. As a result, the value UMA currently provides
continues to be required as telephony services are
migrated to the IMS services platform.
FoR THE LonG HAUL
of mobile operators and is quite complementary to
other initiatives. It's clear UMA not only fits well into
the evolution of a mobile operator's network, it actually
complements other strategic initiatives as well. This is
certainly what is drawing major players like T-Mobile,
Orange and Telecom Italia to the UMA approach to fixed-
mobile convergence.