UMA Today Magazine: Home Zone Issue (Spring 2008) Page 24

UMA Today: What is the role of UMA/GAN

when the RAN moves to LTE?

Tao: The short answer is that UMA will be used in

the same manner it is today: to extend mobile services
over broadband and the IP access network. Just as UMA
supports 2G (A/Gb over IP) and 3G (Iu over IP) services
today, it will evolve to support LTE (S1 over IP).

But to fully answer that question, let me take a quick

step back and explain the role UMA plays in relation to
any 3GPP macro RAN standard.

When UMA/GAN was first defined, it looked to leverage

the many years of work already done within 3GPP for
defining mobile service delivery over a 2.5G (GERAN)
macro radio network and adapt it to enable those same
mobile services to be delivered safely, securely and in large
scale over the internet.

It did that by defining a new controller that connects

into an existing mobile core network using existing
interfaces (the A and Gb interfaces) and then extend those
interface services over IP (i.e. A/Gb-over-IP). The new
controller solves many unique technical problems that
appear only when one considers that it is subscribers, not
the operators, who control when and where their personal
radio base station lights up.

However, 3GPP didn't stop there with UMA/GAN. As we

all know, many operators are aggressively ramping up their
3G/UMTS radio access and core networks. And, the same
need UMA/GAN initially addressed for 2.5G networks (i.e.
extending mobile services over the internet/broadband IP)
also exists for operators deploying 3G networks. To meet
this need, 3GPP recently updated the UMA/GAN standard
to add 3G interface support, thereby enabling Iu interface
services to be extended over broadband (i.e. Iu-over-IP).

So, there are two key things you need to remember about

UMA/GAN. First, from a service enablement perspective,
UMA/GAN seeks to enable 3GPP-based operators to
extend any service they can deliver over their macro
RAN, over broadband. Second, from an architectural
perspective, UMA/GAN follows the simple philosophy of
"design for macro radio access and adapt for broadband
IP access."

In other words, operators should focus their network

design and planning efforts on how they are going to
address the primary mobile service use case (i.e. the
delivery of mobile services over their macro radio access
network). Only then should they seek an approach for
extending delivery of those same services over IP, and to do
so in a manner that causes the smallest disruption to their
overall network design (i.e. adapt for broadband access).

Now, let's look forward to the deployment of LTE. Just

as the need for extending mobile service delivery over
fixed IP networks and the internet exists for operators
deploying 2.5G and 3G RANs, that same need will exist
with the deployment of an LTE-based RAN.

The 3GPP is working very hard right now to complete the

LTE specifications so mobile operators can begin taking
advantage of the cost and performance benefits promised
by the next generation RAN as soon as possible.

As one might imagine, almost all effort right now is being

spent on defining how mobile services will be delivered over
an LTE macro RAN using a new interface into the mobile
core network, the S1 interface. Looking forward, it's
natural to expect that operators will be looking to extend
services being delivered via the S1 interface via broadband
and IP. A UMA/GAN-like solution that can enable S1-
over-IP service delivery becomes a requirement.

UMA Today: So are you saying the business
drivers for UMA remain in an LTE network?

Tao: Absolutely. The business drivers for deploying UMA

for dual-mode handset or femtocell services still remain in
an LTE access network. Operators benefit from off-loading
home or office mobile traffic onto the fixed-line broadband
access network at an incredible cost savings. In addition,
there will always be the challenge of getting very high data
rates to devices when indoors.

The use of local basestations resources, like femtocells

or Wi-Fi, will never go away. UMA, as the only 3GPP
standard for delivering services over IP and broadband,
will continue to fill a key role as the mobile network
evolves.

INTERVIEW

UMA ToDAY

SPRING 2008

Bio

Patrick Tao, vice President of
Technology, kineto Wireless

As Kineto's vice president of technology,

Patrick Tao manages the company's tech-
nology relationships with mobile operators
and network equipment provider partners.
Mr. Tao is also responsible for driving the
continued evolution of UMA technology
through the 3GPP standards body.