Infostations: A Case Study of WINLAB's Systems Approach to Research

WINLAB researchers have identified COST PER BIT as one of the most important constraints on widespread use of the Wireless Internet. Other constraints, in particular transmission rate, user interface, and battery size are the focus of much worldwide activity on Third Generation (3G) Cellular Systems, but while 3G systems will undoubtedly deliver bits faster, they show little progress toward delivering them at a low cost. This is because the cost problem is built into the cellular architecture, which is designed for maximum ubiquity and minimum interference, while delivering the relatively low bit rate associated with voice communications. As a result, the delivery of large amounts of information to people on the move will remain expensive, and the casual and low cost usage that has driven innovation and rapid growth in the Internet is unlikely to occur.

Recognizing that many types of information can tolerate some delay in delivery, WINLAB researchers have proposed a novel system architecture to address this problem. In this architecture, low-power base stations called INFOSTATIONS provide very high bit-rates in small, separated "islands of coverage". These islands of coverage would be perhaps 20-50 meters across. They would be placed at locations that would allow frequent, convenient access for vehicles and pedestrians, such as street corners, toll booths, building entrances, malls and air, rail and bus terminals. Since the Infostations are simple, low power, LAN-like devices and coverage is not continuous, the cost of this infrastructure is many times less than that of a cellular system, yet the information capacity will actually be many times greater. Because the radio path is very short, it is possible to achieve bits rates of hundreds of Megabits, or even Gigabits per second during the brief periods of connection. For a moving vehicle, the connection may last only a few seconds, but in that time a very large file can be delivered, at a cost which is orders of magnitude lower than for ubiquitous cellular coverage. Infostations may be deployed as a complete system, or combined with cellular coverage to achieve both ubiquity and low cost.

Results on a broad range of basic Infostations topics have been published by WINLAB researchers. These, in turn, have laid the foundation for larger focus projects which are now underway or in the planning phase. Currently, a multi-university project called FREE BITS: The challenge of the Wireless Internet, has been funded by the National Science Foundation to explore specific issues related to radio technology for this ultra high-speed, short range path. A second project, Infostations for Emergency Applications, is focused on the use of Infostations to support emergency personnel in a disaster scenario. This project is based on available technology, and is intended to attract Industry participation and begin the transfer of this technology for practical use. A third project, Ultra-Wideband PHY/MAC, is now in the planning phase. This project will focus on the design and prototyping of an ultra-wideband (UWB) physical layer and medium access control, optimized for short-range, super high-speed applications.

The Infostations example shows how WINLAB researchers select an important area of focus, identify a broad system structure that offers a potential solution, conduct initial research to explore that structure, expand to larger focus projects involving sponsors and other universities, and transfer the technology for practical uses.