Scalable Video Transport over Wireless IP Networks

1. Scalable Video Transport over Wireless IP Networks

2. Administrative Issues (05/01/2014) • Draft of Final Report is due on Thursday, April 29, 2014 • Submit a narrative semi-final report containing figures, tables, graphs and references • Final Project Report is due on Tuesday, May 6, 2014 • Submit one hardcopy & one softcopy of your complete report and PPT slides. Orally present your report with PPT slides. • Justify your individual contributions in the project report www.faculty.umassd.edu/honggang.wang/teaching.html

3. Last Class Review: Streaming Video over the Internet • Video Compression • Layered Video encoding/decoding • D denotes the decoder

4. Last Class Review: Streaming Video over the Internet • Application of Layered Video

5. Last Class Review: Protocol Stacks

6. Scalable Video Transport over Wireless IP Networks • Challenges for video over wireless IP networks • An adaptive framework for video over wireless IP networks • Scalable video representations • Network-aware end systems • Adaptive services • Summary

7. Challenges • Unreliability • Fading • Noise • High bit-error rate (BER) • Bandwidth fluctuations • Moving between different networks (LAN to WAN) • Hand-off • …

8. Bandwidth Fluctuations

9. Unicast vs. Multicast • Unicast Multicast

10. Three Independent Techniques • Scalable video Coding • Network-aware adaptation of end systems • Network awareness • Adaptation • Adaptive Services

11. Scalable Video Representations • Layer video encoding/decoding. D denotes the decoder

12. An Application: IP Multicast

13. Adaptive Frameworks • Unify three techniques

14. Network-aware End Systems • Why using network-aware end systems • All layers may get corrupted with equal probability without awareness of channel status • How • Discard enhancement layers at the sender based on network status • Network-aware adaptation • Network monitoring: collection information • Adaptation: adapt video representation based on network status

15. Adaptation/Scaling Architecture • A architecture for transporting scalable video from a mobile terminal to a wired terminal

16. Scaling • The operations of a scaler • Drop the enhancement layers • Do not scale the video • Scaling based on network status • Available bandwidth • Channel quality (BER)

17. Adaptive Services • Objective: • Achieve smooth change of perceptual quality in presence of bandwidth fluctuations • Functions: • Reserve a minimum bandwidth for the base layer • Adapt enhancement layers based on available bandwidth • Provisioning • End-to-end deployment • Local deployment • Components: • Services contract • Call admission control and resource reservation • Substream scaling • Substream scheduling • Link-layer error control

18. Call Admission Control (CAC) and resource Reservation • Objective: • Provide a QoS guarantee while efficiently utilizing network resources • The operation of CAC: check • Whether QoS for existing connection is violated • Whether the incoming connection's QoS can be met • Two parts of resource reservation • Reserve resources along the current path • Reserve resource on the paths from the current base station to neighboring base stations

19. Mobile Multicast Mechanism • Objective • Provide seamless QoS during a handoff • Multicast mechanism • Multicast the base layer to the neighboring base stations

20. Substream Scaling • Objective: • Adapt video streams during bandwidth fluctuations and/or under poor channel conditions • Scaling decision based on utility Function • An architecture for transporting scalable video from a wired terminal to a mobile terminal

21. Utility Functions

22. Substream Scheduling

23. Link-layer Error Control • Forward error correction (FEC) • Automatic repeat request (ARQ) • Delay constrained hybrid ARQ • A receiver sends request based on delay bound of the packet

24. Delay-constrained Hybrid ARQ

25. Summary • Objective: end-to-end solution to providing QoS for video transport over wireless IP networks • A adaptive framework • Scalable video representation • Network-aware end systems • Adaptive services • Advantages of the adaptive frameworks • Perceptual quality is changed gracefully • Resource are fully utilized

26. References • Chapter 15: Y. Wang, J. Ostermann, and Y. Q. Zhang, "Video Processing and Communications," 1st ed., Prentice Hall, 2002. ISBN: 0130175471. • D. Wu, Y. T. Hou, and Y.-Q. Zhang, “Transporting real-time video over the Internet: Challenges and approaches,” Proc. IEEE, vol. 88, no. 12, pp. 1855–1877, Dec. 2000. • D. Wu, Y. T. Hou, and Y.-Q. Zhang, “Scalable video coding and transport over broad-band wireless networks,” Proc. IEEE, vol. 89, no. 1, pp. 6–20, Jan. 2001.

27. Backup

28. Unreliability: Wireless Signal Propagation • Propagation in free space always like light (straight line) • Receiving power proportional to 1/d² in vacuum – much more in real environments (d = distance between sender and receiver) • Receiving power additionally influenced by fading (frequency dependent) • Shadowing • Reflection at large obstacles • Refraction depending on the density of a medium • Scattering at small obstacles • Diffraction at edges refraction shadowing reflection scattering diffraction