238_1_lecture1 - 1 EE 238: Multimedia communications and...

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1 EE 238: Multimedia communications and Multimedia communications and networking networking Prof. Mihaela van der Schaar Prof. Mihaela van der Schaar email: email: mihaela@ee.ucla.edu mihaela@ee.ucla.edu www www - - page: page: medianetlab.ee.ucla.edu medianetlab.ee.ucla.edu
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2 Outline Brief course introduction First lecture: Delay-sensitive communications and networking: challenges, problem space and applications Questions/comments/observations are always encouraged, at any point during the lecture!!
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3 Why attend a multimedia communications and networking class? Answer 1: Practical relevance Multimedia communications over Internet and wireless networks - exploding! Just a few examples: - Wireless/Internet multimedia streaming applications YouTube, Real-Player, Apple QuickTime, iPhone, Microsoft MediaPlayer, etc. - Video conferencing and chatting over Internet/wireless - Peer to peer media streaming
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4 Multimedia Comm Applications Delay-sensitive applications Entertainment P2P TV Emergency services Surveillance Telemedicine Multi-party videoconferencing Telepresence Augmented reality Distributed gaming RG Access Point DVD Recorder HDTV SDTV PDA Bridge Internet Internet Access Content Server IN-HOME STREAMING STARBUCKS MEETINGS WAYPORT Communication over packet-based networks Wired: Internet, overlay networks, P2P Wireless: Cellular, WLANs, Cognitive Radios
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5 Now and …. then…. . When ARPANET was born, the model for the network entailed a set of terminals and servers, wired by a high-speed backbone. Much has changed since then. As more powerful wireless Internet devices become available, the digital landscape is increasingly becoming interactive, and rich of MULTIMEDIA
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6 Multimedia Communications over Internet and wireless networks Original VIDEO Transmitter/Server/Proxy Receiver/Client Packet-based Network Received VIDEO Transmission Strategy Receiving Strategy Video Encoding Video Decoding Source Traffic Shaped Traffic Packet-loss Bandwidth variations No/limited QoS
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7 Received video - Example Coded, No loss 3% 5% 10%
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8 Packet networks (e.g. wireless networks) are heterogeneous in bandwidth, reliability and receiver device characteristics / Packets Loss Delayed (propagation and queuing - variable, delay jitter) Excessive delay = loss for real-time applications Lost Inevitable under “best effort” delivery Packet losses can vary from 0.1% to 10% or more Time varying characteristics Difficult to characterize and measure Discarded (at the receiver side) If the complexity/power of the receiver is limited Bandwidth fluctuation multipath fading, co-channel interference, noise, mobility, handoff, etc competing traffic Receiver architecture heterogeneity Computing capability, buffer availability, display resolution, power limitation (transmission and processing)
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This note was uploaded on 10/19/2011 for the course ELECTRICLA 216A taught by Professor Marković during the Fall '10 term at UCLA.

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238_1_lecture1 - 1 EE 238: Multimedia communications and...

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