Inter-Network Roaming , Handset User Interfaces , Human Interfaces

A critical feature of most mobile network standards has been the support of internetwork
roaming, where a subscriber to one network is able to use his phone on
another network. Roaming is represented by both a commercial agreement
between two network operators to accept roamers and to provide billing data
in an agreed format; it is also a technical issue where the handset must be capable
of operating on both networks.

The GSM and UMTS standards have always included roaming as a key aspect,
and phones sold to subscribers on one network should work on other networks using
the same technology. However, the roaming user may not always have access to the
same services when roaming and indeed the look and feel of the visited network may
be somewhat different from the home network. Recently, work has been undertaken
in the standards to minimize the difference seen by roamers across networks. This
gave rise to the concept of the virtual home environment (VHE), which is based on
Intelligent Network (IN) techniques and appropriate inter-network signaling.

The situation for some roamers is eased in some cases by the existence of agreements
between networks that allow a roamer to dial his normal shortcode for, say,
mailbox access, and for the networks to translate this number behind the scenes.
While this may not be based on the VHE standards, it does start to solve the issues
of look and feel.

Another factor aiding some roamers is the coalescence of the market around a
number of large global operators. Once a mobile network operator owns multiple networks,
it is clearly able to provide a consistent user experience across those networks.

Handset User Interfaces
Manufacturers often have entire teams or departments that are responsible for the
design and implementation of user interfaces (UI), as this aspect of handset design
is so critical. The complexity of handsets and the multitude of functions they contain
make the UI critical in influencing the user experience. The UI supported by a
device will depend largely on device capabilities and will range from a very simple
UI for voice-centric handsets to very complex icon-oriented UIs, maybe incorporating
touch-screen technology, for data-centric devices. The best UIs are of course
those that are largely intuitive and that make redundant the complex (and costly to
produce) user handbooks or operating manuals.

The dynamics of the market often come into conflict at the UI. The handset
manufacturer will have spent a lot of time and money designing the UI, only for the
network operator to insist in some cases that it be replaced, in whole or in part, with
an operator-specific UI. This area of UI customization is another area in which the
manufacturer must fight to preserve brand identity.

Human Interfaces
The issue of user-personalization is also influencing the UI; many end users want
in some way to personalize the UI so it gives more ready access to the features and
capabilities that they use most often. The human or user interface on handsets
consists of a number of elements, including the display, the keypad or keyboard,
the navigation keys, and any soft keys or hot keys. The precise configuration of the
UI is determined by a number of factors, such as the device type and manufacturer
preferences