MPEG-21-based Cross-Layer Optimization Techniques for enabling Quality of Experience

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MPEG-21-based Cross-Layer Optimization Techniques for enabling Quality of Experience

  1. 1. MPEG-21-based Cross-Layer Optimization Techniques for enabling Quality of Experience<br />Christian Timmerer<br />Klagenfurt University (UNIKLU)  Faculty of Technical Sciences (TEWI)<br />Department of Information Technology (ITEC)  Multimedia Communication (MMC)<br />http://research.timmerer.com  http://blog.timmerer.com  mailto:christian.timmerer@itec.uni-klu.ac.at<br />Acknowledgments: DANAE, ENTHRONE, P2P-Next, ALICANTE projects funded by EC, SCALIPTV/SCALNET funded by FFG, ASSSV funded by FWF and, in particular Michael Eberhard, Ingo Kofler, Robert Kuschnig, Michael Ransburg, Michael Sablatschan, Hermann Hellwagner<br />
  2. 2. Outline<br />Background / Introduction<br />Cross-layer designs & optimizations<br />MPEG-21 Digital Item Adaptation<br />How to exploit MPEG-21 for XL optimizations?<br />Cross-Layer Model (XLM)<br />Instantiation of the XLM by utilizing MPEG-21 metadata<br />Cross-Layer Adaptation Decision-Taking Engine (XL-ADTE)<br />Conclusions<br />2010/01/20<br />2<br />Christian Timmerer, Klagenfurt University, Austria<br />
  3. 3. Background / Introduction<br />Cross-layer designs<br />Aim: increase QoS/QoEby performing coordinated actions across the network layers =&gt; violating the protocol hierarchy and isolation model <br />Approaches: bottom-up or a top-down or jointly optimizing parameters at the different layers<br />Common property: compromising interoperability in favor of performance<br />Increasing the interoperability of cross-layer designs by adopting an open standard – MPEG-21 Digital Item Adaptation – for describing the functional dependencies across network layers<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />3<br />
  4. 4. Digital Item Adaptation<br />DIA := syntax and semantics of tools that assist in the adaptation of Digital Items<br />Goals:<br />Satisfy transmission, storage andconsumption constraints as well asQuality of Service (QoS) management<br />Enable transparent access to (distributed)advanced multimedia content by shieldingusers from network and terminal installationissues<br />Codec Format-independent mechanisms that provide support for Digital Item Adaptation in terms of:<br />Resource adaptation<br />Description adaptation<br />Quality of Service management<br />The adaptation engines themselves are non-normative tools<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />4<br />
  5. 5. 2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />Usage Environment Description (UED)<br />Terminal Capabilities<br /><ul><li> Codec Capabilities
  6. 6. Device Properties
  7. 7. Input-Output Characteristics</li></ul>User Characteristics<br /><ul><li> User Info
  8. 8. Usage Preference & History
  9. 9. Presentation Preferences
  10. 10. Accessibility
  11. 11. Location</li></ul>fundamental inputto any adaptation engine<br />Natural Environment Characteristics<br /><ul><li> Location & Time
  12. 12. Audio-Visual</li></ul>Network Characteristics<br /><ul><li> Capabilities
  13. 13. Conditions</li></ul>5<br />Context-related metadata describes the usage environment in terms of terminal capabilities; network characteristics; user characteristics; natural environment characteristics;<br />e.g., codec capabilities = mp2, ML@MP; available bandwidth=1500kbps; visually impaired; high-level ambient noise;<br />
  14. 14. AdaptationQoS and Universal Constraints Description<br />Content-related metadata – AdaptationQoS– describes the relationship between constraints; feasible adaptation operations satisfying these constraints; associated utilities (qualities);<br />e.g., available bandwidth is 384kbps, terminal display is CIF; reduce bit-rate; quality at QCIF/30fps/QP=10 versus CIF/10fps/QP=15e.g., bit-rate = 256kbps, frame-rate=30fps, resolution=CIF, etc.<br />Universal Constraints Description (UCD): mathematical approach based on an optimization problem<br />find values for the variables representing adaptation parameters that do not violate the limitation constraints (feasibility) and maximize the optimization constraint(optimality, objective function)<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />6<br />
  15. 15. How to exploit MPEG-21 for XL optimizations?<br />Three-step approach<br />Cross-Layer Model (XLM): describing the relationship between QoS metrics at different levels <br />No specific notation (e.g., graphical)<br />For example: <br />Instantiation of the XLM by utilizing MPEG-21 metadata<br />AdaptationQoS (AQoS): describe the relationship between constraints, feasible adaptation operations satisfying these constraints, and associated utilities (qualities)<br />Usage Environment Description (UED): context information (network conditions, terminal capabilities, user preferences, etc.)<br />Universal Constraints Description (UCD): limitation and optimization constraints <br />Cross-Layer Adaptation Decision-Taking Engine (XL-ADTE)<br />Software module solving an optimization problem adopting any algorithm<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />7<br />
  16. 16. Example: Adaptive XL-based Streaming<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />8<br />supported display resolution, frame-rate<br />TID, DID, QID<br />packet loss, jitter<br />max. payload size, forward error correction<br />signal strength, physical rate<br />Basic Cross-Layer Model<br />temporal id (TID)<br />dependency id (DID)<br />quality id (QID)<br />packet size<br />vertical and horizontal resolution<br />bit rate<br />frame rate<br />
  17. 17. Advanced Cross-Layer Model<br />Desirable characteristics<br />TCP friendliness: long-term throughput similar to TCP<br />Responsiveness: time to act upon a certain event<br />Smoothness: variation experienced for a particular flow<br />TCP-friendly Rate Control Protocol (TFRC)<br />Throughput T in bytes/sec is modeled as a function of<br />Segment size sin bytes<br />RTT estimate r in seconds<br />Loss event rate pas a fraction between 0.0 and 1.0<br />TCP retransmission timeout value tRTOin seconds (simple tRTO= 4r)<br />Adapts sending rate accordingly<br />If Tcurr &gt; Tnewthen reduce rate else increase rate<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />9<br />
  18. 18. Instantiation of XLM using MPEG-21<br />AdaptationQoS (AQoS)<br />Parameters (TID, …) as IOPins<br />Basic XL model as Look-Up Table (LUT)<br />Advanced XL model as Stack Function (SF)<br />Usage Environment Description (UED)<br />Display resolution as display capabilities<br />Max bit-rate of codec as codec capabilities<br />RTT as packetTwoWay<br />Loss event rate by using the packetLossRate<br />Universal Constraints Description (UCD)<br />Limit constraints<br />resulting bit-rate &lt; TFRC transmit rate<br />resulting bit-rate &lt; max bit-rate of codec<br />video resolution &lt; display size<br />Optimization constraint: max bit-rate<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />10<br />
  19. 19. Cross-Layer Adaptation Decision-Taking Engine (XL-ADTE)Example: Adaptation of Scalable Video<br />MPEG/ITU-T Scalable Video Coding (SVC)<br />3 dimensions of scalability: spatial, temporal, signal-to-noise ratio (SNR)<br />Spatial dimension [pixels]: 640x360, 1024x576, 1920x1080<br />Temporal dimension [fps]: 15, 30<br />Step 1: Determine Variables<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />11<br />Table 1. (a) Adaptation Parameter Variables; (b) Content Property Variables.<br />
  20. 20. Example: Adaptation of Scalable Video (cont’d)<br />Step 2: Identify Functional Dependencies<br />Step 3: Restrict Solution Space (Limit Constraints)<br />Step 4: Define Objective Function<br />maximize FrameRate<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />12<br />
  21. 21. Example: Adaptation of Scalable Video (cont’d)<br />Possible adaptation parameters<br />Feasible adaptation parameters<br />Optimal adaptation parameters<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />13<br />
  22. 22. Conclusions<br />Three steps to cross-layer interoperability<br />Cross-Layer Model (XLM): describing the relationship between QoS metrics at different levels<br />Instantiation of the XLM by utilizing MPEG-21 metadata<br />Cross-Layer Adaptation Decision-Taking Engine (XL-ADTE)<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />14<br />
  23. 23. Thank you for your attention<br />... questions, comments, etc. are welcome …<br />Ass.-Prof. Dipl.-Ing. Dr. Christian Timmerer<br />Klagenfurt University, Department of Information Technology (ITEC)<br />Universitätsstrasse 65-67, A-9020 Klagenfurt, AUSTRIA<br />christian.timmerer@itec.uni-klu.ac.at<br />http://research.timmerer.com/<br />Tel: +43/463/2700 3621 Fax: +43/463/2700 3699<br />© Copyright: Christian Timmerer<br />15<br />2010/01/20<br />Christian Timmerer, Klagenfurt University, Austria<br />

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