Motivation (wicat)
The cellular network provides
"anytime-anywhere" service needed for urgent messages. However, for
many information services, "manytime-manywhere" service is sufficient
and can be provided with higher data rates, lower power consumption,
and lower cost. Infostations provide high bandwidth wireless
connectivity in isolated coverage areas, allowing mobile users to "fill
up" their terminals with the information they need as they pass through
a coverage area. This paradigm is well-suited for location dependent
information, which is most relevant when the user is in a particular
area (local maps, information about local restaurants, etc.) and is also
useful when the user can tolerate some delays in exchange for lower
cost service.
[go back]
Goals
WICAT's Infostation Project is
developing a prototype Infostation system and information services that
run on the system. Development and deployment of the Infostation
paradigm will create value in several industrial sectors. Wireless LAN
equipment manufacturers can benefit from expanded markets. Hybrid
Infostation-Cellular systems will allow cellular service providers to
offer differential service with differential pricing, conserving scarce
bandwidth for urgent messages and for customers who are willing to pay
premiums for immediate data access. Service industry will be able to
provide useful information to their customers inexpensively, which in
turn, can increase revenues.
[go back]
Approach
The Infostation system is targeted toward pedestrians carrying notebook computers or PDAs. An Infostation consists of an 802.11 access point along with a server, which is connected to the Internet. Before arriving at an Infostation, a user selects categories of information that are of interest. As the user passes through the Infostation coverage area, the system automatically determines which of the data items available at the Infostation are of interest and downloads them. This is done without intervention from the mobile user. Since many information items will be of interest to numerous users simultaneously, data broadcasting and multicasting are used for many of the data transfers.
Research issues include design of
algorithms and protocols to maximize the chance that users will
successfully receive the information they need while in range of an
Infostation, algorithms for coordinating Infostations with one another
and with the cellular system, techniques for conserving power in the
mobile terminal, and protocols for uploading and forwarding information
from the user's terminal via the Infostation.
[go back]
|
 |