MOBILE COMPTING
WIRELESS SENSOR NETWORKS

Mobile computing
Mobile computing is a term describing a person's ability to use technology while moving, as opposed to portable computers, which are only practical for use while in a stationary configuration. The Physical entities in mobile computing are computers that change locations and the Logical entities are instances of a running user
application or a mobile agent.Whereas the Mobile agents can migrate any where over inter-net, the active applications can only move to a local
cluster of computers.

Requirements:
A wireless n/w to support outdoor mobility and
handoff from one n/w to the next at a pedes-
trian or vehicular speed.
- Traveler in car using laptop connected with a
GSM phone “ engaged in mobile computing.
access to computer network all the time
at any location by any person is called ubiquitous computing or pervasive computing.

Challenges of mobile computing
The major challenges include:
Routing data and messages, Naming and locating, Creation of Mobility/context aware applications, maintenance of Reliability in presence of disconnection, Data management, Security, and devising rapid Transaction models.
Conventional Distributed computing know works on
static wired network. but here, the Node may initiate computation some where and migrate to another place.. mobility arises the problems:
Searching for current location of a mobile
node and imposing a communication structure.

Physical location of mobile is not the network
address,so routing willl be a problem. Internet community solves this by using Mobile IP whereas Cellular community solves it with location
management of cellular phone users.

Informing when it migrates is a responsibility of the mobile unit. but mobile units can either never inform(for units
receiving few messages and for units which
donâ„¢t move during receiving.
) or Always inform(suitable for units receiving
messages frequently
) Ad hoc network routing is the ultimate challenge. Main cause of loss of packets in wired network
is congestion because error rates are very low.


[attachment=1141]

---

For WIRELESS SENSOR NETWORKS, visit this thread:
http://studentbank.in/report-WISENET-Wir...nar-Report