2. INTRODUCTION Mobile Computing  A technology that allows transmission of data, via a computer, without having to be connected to a fixed Physical link.  These days there is rapid movement towards wireless communication in the Giga Hertz spectrum which allows for new concepts such as “Hidden computing”.  Mobile computing is discussed in terms of the input and output interface methods used to interact with mobile devices.  Where two dimensions, mobility and connectivity, are the continuums used to asses the functionality for mobile devices and clients. Under this comes the area of mobile networks such as WLANS and WWAN.  The two dimensions, mobility and connectivity, are the continuums used to asses the functionality for mobile devices and clients.

3. WWANS and WLANS

4. NEED FOR MOBILE COMPUTING  Device independent communications anytime, virtually anywhere:

5. Information support for "Mobilers"

6. Gathering external information

7. Providing external information to Mobilers:

8. Technical Details  Mobile- www introduces an extension for HTTP which uses an intelligent compression and administration mechanism to save connection time and money.  Mobile -WWW consist of a special web-client which request a Qos for the content; this QoS is defined according to the users preferences, the available bandwidth and the cost of transmission.  A wireless access technology DECT (Digital Enhanced Cordless Telecommunications interface) has been deployed to connect mobile devices to backbone

9. Architecture " Requirements for mobile services are stability, bandwidth/cost considerations, integration into the familiar environment, application transparency, security and extendibility.”  Connection management including  Caching  Localization management including: Locating required resources in a foreign environment and tracking the user if required.  Authentication and encryption.  Profiling

10. Architecture:  Mobility services architecture : Common Mobility Services (CMS). Mobility Management Services (MMS). Special Mobility Services (SMS).

11.  Mobility Environment Architecture: To distinguish from conventional client-server and network tunneling systems we chose the notions front-end for a mobile host, backend for a fixed host that is servicing mobile nodes and relay for an access point to the backbone.

12. Limitations And Proposed Solutions:  SECURITY Wirelessly connected devices can easily breach two of the most fundamental network security policies:1)confidentiality and 2)authentication. Steps in designing for security in mobile computing networks:  Application and System Assisted Security which is primarily use of user passwords and similar mechanisms.  Dial back as a Security Technique.  Firewalls - Security Servers at the Host.

13. LIMITED ROAMING:  Once application sessions are established over existing protocols, the network assumes that a device remains attached to that segment for the duration of the session.  Deploying wireless solutions has introduced new issues not found in more traditional network architectures. One of the most difficult issues is the "roaming handoff":

14. The Solution :  A lot of wireless users today feel that they are using "bleeding edge" technology.  If a mobile device is equipped with more than one wireless card, the software could govern the hardware to automatically switch onto the card that offers the highest bandwidth.  When a mobile device becomes unreachable because it suspends operation, moves out of coverage, or changes its current "point of presence" address (roaming).  Another way of dealing with the problems faced with roaming is to use subnet roaming using IP.

15. BATTERY RELATED ISSUES IN MOBILE & WIRELESS –An Overview  Mobility and portability inherently requires a source of electricity that does not depend on conventional wired power.  Our requirements for battery power in mobile devices are running ahead of the improvements in battery capacity.  While we are making advances in lower consumption of power for the same.  Security technology like more powerful encryption is demanding on battery power.  Battery runs out rather quickly in most handheld devices.

16. Trends in Improving Battery Life for Handheld Devices: This progress is centered on following initiatives :  Reducing the power requirements of chips and processors.  Superior power management techniques.  Better batteries based on conventional technology.  New battery technologies like fuel cell are also being explored.

17. Fuel Cell Technology for Mobile devices: In fuel cells, hydrogen mixes with oxygen to generate electric current through water. Technology problem is that hydrogen is flammable.

18. APPLICATION PERSISTENCE : Critical applications are still relegated to stationary or desktop systems. When a company tries to deploy these applications to mobile devices, mobile users spend a lot of time getting back on the network after losing their connections. They must login again, re-authenticate, sometimes navigate through multiple screens to find the point where they left off, and then re-enter any lost data. In the end, users are frustrated and less productive.

19. Solution But by using the server in places where there is the slightest possibility of loss in data the network application sessions would not be terminated even when:  A mobile device suspends operation;  A user disconnects or removes the wireless card from the mobile device  Or a device temporarily moves out of the coverage area.

20. conclusion Use of Artificial Intelligence may allow mobile units to be the ultimate in personal secretaries, which can receive emails and paging messages, understand what they are about, and change the individual’s personal schedule according to the message. Indeed, technologies such as interactive television and video image compression already imply a certain degree of mobility in the home i.e. Home Shopping, etc using the mobile data communication technologies discussed, this mobility maybe pushed to extreme. The future of mobile computing is very promising indeed, although technology may go too far, causing detriment to society.