Making the Case for Distributed Terminals

by Anh Vo Viet, Orange Innovation

While cell phones have been used for voice applications for several years, they are now entering the data world, bringing the potential for exciting new applications to cellular handsets. But realizing this potential requires integrating additional technology within a cellular phone, increasing complexity for manufacturers.

An attractive alternative to this "all-in-one" approach is the idea of a distributed terminal, in which a gateway device contains cellular communications functions that can be used by surrounding application-specific devices. The benefits of this distributed approach, which is also referred to in standards bodies as a User Equipment Split, extend to users and manufacturers alike:
  • Users benefit from higher quality accessories. In order to keep the dimensions of the handset reasonable, manufacturers of all-in-one terminals are forced to make quality trade-offs with some applications, such as lowering the photo resolution or decreasing the screen size offered by an integrated camera.
  • Manufacturers gain added flexibility. Handset manufacturers are interested in integrating many new technologies, including color displays, cameras, MP3 playback capability and GPS. But it is difficult to add such new functions to an existing cell phone, while retaining an acceptable form factor and price.
  • Manufacturers gain new latitude in the design and look and feel of devices, ultimately resulting in a richer variety for consumers. While a "smart phone" is an example of a converged device that integrates cell phone and PDA functionalities, it is not likely to fully replace the PDA. As a result, the user is condemned to accumulating several devices - cellular phone, laptop and PDA, for example - and struggling to make them communicate with one another.
The distributed terminal concept, on the other hand, offers users the flexibility to choose the exact functions they want from a range of devices, without having to buy an integrated unit with more functionality than they really need. It provides flexibility in terms of cost as well as the types of communications devices employed in different environments, such as office, home and public places.

A mobile handset best fits in the center of this world, due to its portability. But the distributed terminal concept allows for additional accessories to be employed with the handset, forming a personal-area network (PAN). The configuration of the PAN will change as the users' environment changes and they employ different accessories. In a corporate environment, users may communicate with accessories such as a laptop, PDA and printer, while at home the accessories could be a television set or stereo. During leisure time, users may employ an MP3 player, camera or headset.

A key element in the distributed terminal concept is Bluetooth, which facilitates wireless connectivity between electronic devices. Bluetooth offers a number of design features that enable it to be used virtually anywhere:
  • Small form factor
  • Low cost
  • Short range radio for reduced power consumption
  • Resistance to interference
Although Bluetooth suffered from interoperability issues early on in its development cycle, today concepts such as the distributed terminal can fully benefit from the flexibility and freedom Bluetooth offers.

Both converged and distributed terminals aim to offer increased functions and applications for end users, an idea that raises complexity issues. Whatever concept is employed, the resulting technology must simplify life for the user.

Anh Vo Viet is Terminal Innovation Program Manager for Orange innovation, the department within Orange that is responsible for developing all new technologies.