The Virtual Home Environment (VHE) Concept

In the VHE , users are consistently presented with the same personalized
features, user interface, customization, and services — in whatever network
they are located, or terminal they may be using (assuming that capabilities in the
network and terminal exist).

In defining the VHE, it is useful to introduce the concept of the home environment.
This can be synonymous with the user’s home network and subscribed
services, but can also include other value-added service providers (VASPs), which
are accessed through this home network service provider. The home environment
provides (and controls) the personal service environment in association with the
user’s own personal profile.

The serving network describes the network to which the user is attached at
the time, and thus may be a network in which they are roaming (when traveling
abroad). In the VHE concept, this network should be invisible to the user, with services
transported seamlessly. It may be another mobile network, but could equally
also be applied to a fixed network, the Internet, etc., depending how the users
choose to access their services at any one time.

VHE also takes into account the possibility of value-added service providers, who
may be part of neither the home nor the serving environment. For example, a banking
service may be provided directly from a bank VASP. Users should still be able to
transparently access these services whether or not they are in their home network.
Location Platforms
3G systems (including UMTS) are designed from the outset to provide for accurate
location of user equipment (mobile handsets), and this allows for providing
advanced location-based services. The location information is collated and managed
by location platforms (primarily the serving mobile location center and the gateway
mobile location center). This information can then be accessed and used by the
service platform in a variety of different services.

In UMTS, the location determination can be achieved in three main ways (discussed
shortly), and may also be provided as part GSM or GPRS.

The location information can be used by the PLMN operator, emergency services,
value-added service providers, and for lawful interception by authorized
agencies. The PLMN could use location information for a variety of purposes,
including handover optimization. Emergency services can radically improve the
overall response time if automatic mobile terminal location is provided. Valueadded
services can be significantly enriched and in some cases enabled — for
example, downloading a map showing where the subscriber is and how to reach a
local address.

The quality of location information is defined in terms of horizontal accuracy
(10 to 100 meters, according to the application), vertical accuracy (up to 10 meters),
and response time (no delay, low delay, or delay-tolerant criteria). It can also be
defined by priority (e.g., emergency services have highest priority), time stamping
(vital for some applications such as lawful interception), security measures (to
ensure controlled access to user location information), and privacy.