UMA & IMS - Overview

I have been wanting to blog about 3GPP UMA (Unlicensed mobile access) for quite some time, but have been postponing it for the want of a clear definition. Today I found one, thanks to this article in Unstrung. Here it is:

UMA is the 3GPP global standard for Mobile/Wi-Fi convergence that enables mobile subscribers to roam and handover between cellular networks and WLANs using multi-mode mobile handsets.

The article talks about Infineon (IMS) and Kineto (UMA) joining hands to provide IMS services seamlessly across mobile and Wi-Fi networks. While UMA is the 3GPP standard for Mobile/Wi-Fi convergence, IMS is a network specification for delivering IP services across fixed and mobile networks. From the same article, a definition for IMS:

IMS is the open, standardized IP multimedia and telephony core network specification for mobile and fixed operators that is defined by 3GPP (3rd Generation Partnership Project).

As a part of the IMS specification, IMS uses SIP (Session Initiation Protocol) as one of its underlying protocols. More on IMS and SIP here.

Infineon and Kineto come together to provide services enabled through IMS, seamlessly across your Mobile and Wi-Fi network. To expand a bit on that, imagine watching MobileTV (or a VoIP call) over your GPRS connection outside the home. As you step in the Wi-Fi network in your home, the same IP services are available to you on the phone through your Wi-Fi network instead of the GPRS network - and the beauty of this is that it happens seamlessly.

To make this happen, UMA treats your Wi-Fi network as mini-cell base station which makes for the easy hand-off between your cellular and Wi-Fi networks. Here is some stuff from Kineto on how UMA enables broadband IMS (by Director of Mktg, Kineto).