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Explore the system architecture of ubiquitous computing, focusing on multimedia, event-based interactions, and location-aware services that are privacy-conscious and invisible to users. Learn about location sensing, resource discovery, and intelligent end systems, all transferring information via SIP servers. Discover the benefits of location-based services and control modes, resource discovery, call control, messaging, and access control in a prototype implementation like the CINEMA system designed for enhanced connectivity in various domains.
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Ubiquitous Computing in Home Networks Henning Schulzrinne, Columbia University Stefan Berger, IBM Research IEEE Communication Magazine 2003
E-E-E Everyone can communicate to EverythingEverywhere
Ubiquitous Computing • Multimedia • Device integration • Event-based • Location-aware • Privacy-conscious • Invisible to user
System Architecture • The context around the user • Location information • Multimedia resource • The intelligent end system the user hold • Retrieves the location and resource information • Transfers the information to SIP server • Control the resources
System Architecture • The core of the intelligent end system • Location sensing • Resource discovery and management • Call control
Location Sensing • Self determines • GPS • Useless indoor • The field strength of wireless access point • Need two APs • Location beacon • Bluetooth • IR/RF • DHCP Server
Location-Based Service • Triggers automated behavior • Selects watchers • Governs communication behavior
Location-Based Service Two control mode • User centric • Selects the types of devices for witch the user has defined preference • Device centric • Device subscribe to user presence and store preference
Resource Discovery and Control • Back-to-back user agent • A logical entity that receives a request and processes as a user agent server(UAS) • And acts a user agent server(UAC) to determine how to answer the request and generates requests
Call Control Event-triggered actions • Received from the location sensing • Service discovery • Inbound or outbound call
Control Messaging Using • SIP • Text-based message • XML • HTTP • Encode as URI parameter • SOAP(Simple Object Access Protocol) • More powerful • More complex
Access Control • Explicitly registered to local server • RADIUS or DIAMETER (AAA) • Location information
Prototype Implementation • The CINEMA system • Columbia InterNet Extensible Multimedia Architecture • SIP proxy, redirect, registration server(SIPD) • SIP voice mail • SIP conference service • Service logic execution environment(SLEE)
Visited domain SIP-based ubiquitous computing in a hotel
Conclusion • Presented a global-scale ubiquitous computing architecture • Based on standard SIP and SLP • Implementation CINEMA system