Information Technology Reference
In-Depth Information
GPS satellite
Positioning
database
Server
agent
GPS data
GPRS
Internet
Cell-ID
Base Transceiver
Station (BTS)
Location
service
server
Other
server
agents
Client
agent
Other
learning
server
Online optimal
student group
mLearning
database
Figure 16.3
The conceptual system architecture.
mobile devices by determining the amount of shared similar location infor-
mation. This approach could group online mobile learners within the radius
of 500-1500 meters (almost one mile) in an urban area and 15 km (about
9 miles) in rural area.
Since GPS embedded mobile devices have become more and more popular,
the client agent has to be able to work with this type of mobile devices. When
the client agent is running on a mobile device, it will identify if the GPS
coordinates are available (internally or externally). If yes, the client agent will
periodically retrieve the GPS coordinates and send the position coordinates
of the mobile device with its cellular network location data to a central loca-
tion server agent to achieve high accuracy (within 3 meters or about 10 feet)
location-based grouping.
However, the GPS technology has its own drawbacks. The GPS position-
ing is not available inside buildings or even between tall buildings, which
restrict the view of the sky, and it also increases battery consumption and
data-acquisition time. Therefore, it is very important to sufficiently use the
GPS location data to update the cell geographic location information data-
base and to enrich and correct the existing location database, eventually to
enhance the over all location accuracy and the grouping performance.
The fundamental step of the client agent is to obtain the GPS coordinates
from a mobile device. There are various software programs doing this job. The
cellular phone manufacture also provides the data communication solutions,
such as Nokia's PC Connectivity serial programs as high-level data commu-
nication development kits. Understanding the data communication protocol
of a mobile device will be highly efficient for the client agent development
