Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 1 Issues and Limitations on Mobile Computing Contents Wireless Issues –Mobile Computing –Wireless Architecture –Wireless Access Technologies –Wireless Applications Wireless Limitations Middleware for Mobile Computing Summary & Further Issues

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 2 Mobile Computing What is the computing? –Operation of computers as Oxford Advanced Learners Dictionary states. What is the mobile? –That someone/something can move or be moved easily and quickly from place to place as Oxford Advanced Learners Dictionary states. What is the mobile computing? –Users with portable computers still have network connections while they move.

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 3 Wireless Architecture Personal Communication Network (PCN) –Extension of nowadays Infranstructure ITU Spesifications –Hierarchical Cell Structure –Global Roaming –Expansion of Radio Spectrume

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 4 Wireless Access Technologies Past and Current State –AMPS, TDMA, CDMA in USA, GSM in Europe, Public Packet Radio and CDPD –Private Mobile Radio –Wireless LAN –Satelite Systems

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 5 Wireless Applications Horizontal Applications –Yellow Pages –Movies Info Vertical Applications –Access to large amount of data (databases) Requirements –support to any mobile appliance –support to any network –capability to sustain long - short time disconections –access replicated data or databese file systems

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 6 Wireless Limitations Mobility –Auto configuration of the system –Location management Lookups (Track users call) Updates (Update users position and/or data) –Heterogeneity –Security Authentication –Spectrum range

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 7 Wireless Medium –Cost of Networks –Quantity and reliability of bandwidth –Environment obstacles Portability = Mobile Restrictions –Low Resources –Battery Constraints –Lack of Security Wireless Limitations

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 8 Middleware for Mobile Computing Middleware –What is the middleware? – Considerations Application Integration Device Independence Mobile Agents Wireless Application Protocol (WAP) –bring Internet content to digital cellular phones –creation of global wireless protocol specification –enable creation of contents with wide range of usage –to extend existing standards

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 9 WAP Research Interests Over the air provision Persistent Storage SIM Tool Kit Location Services Network Management Broadband Services Corporate Data Access IMT (3G) Multimedia Capabilities

Theodoros Chrysafis - Computer Science Department - CITY Liberal Studies - (24-25/05/2002) 10 Summary & Further Issues Wireless Issues Wireless Limitations Wireless Middleware Research on: –Broadcast –Location Management –Spectrum Utilisation –Extension on existent ptotocols