Information Technology Reference
In-Depth Information
2 . 2
C h a r a c t e r i s t i c s o f t h e M o b i l e E n v i r o n m e n t
Mainly, three characteristics distinguish the mobile environment; namely, wire-
less medium, mobility, and portability.
Table I
summarizes the characteristics of the
mobile computing environment and some of the resulting challenges.
2.2.1
Wireless Medium
Whether the communication is based on the satellite link that spans one third of
the earth or a wireless LAN within a building, the common ground among all wire-
less systems is the fact that communication is done via the air (and not via cables).
This fact changes a major underlying assumption that was the basis for conventional
distributed algorithms. The physical layer of the connection is no longer the reliable
coaxial or optic cable that has been assumed all along. Communication over the air
is identified by frequent disconnections, low data-rate, high cost, and lack of security
[4,5,21,36-38,65]
.
T
ABLE
I
C
HARACTERISTICS OF
M
OBILE
E
NVIRONMENT AND
R
ESULTING
I
SSUES
Mobile environment characteristics
Resulting issues
Wireless connection
Frequent disconnection
Communication channel
High cost
Low bandwidth
Network measurement
Low data rate
High error rate
Security (eavesdropping)
Mobility
Frequent disconnection
Motion management
Location-dependent data
Heterogeneous networks
Interfacing
Data rate variability
Security (privacy)
Portability
Security (vandalism)
Limited resources
Limited energy source
User interface
