1. Video Quality Evaluation for Wireless Transmission with Robust Header Compression Fourth International Conference on Information, Communications & Signal Processing Fourth IEEE Pacific-Rim Conference On Multimedia 15-18 December 2003, Meritus Mandarin Hotel, Singapore Seeling, Fitzek, Reisslein

2. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Content Introduction & Motivation Header Compression Schemes Robust Header Compresion (ROHC) RFC3095 Video over ROHC Methodology and Testbed Setup Results Conclusion

3. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Introduction Video services over wireless networks are gaining more and more interest Services are needed that convince customers to buy new equippment (e.g., 3GPP networks) 3GPP networks support video services such as the IMS and the MBMS entities Problem: Video services need much more bandwidth than voice calls, which makes them hard to sell

4. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Motivation Video services are transmitted over IP networks using the RTP/UDP/IP protocols Video is encoded efficiently, but the protocol stack overhead is not The protocol overhead comprises a large portion of the traffic (even more for small video formats as for the mobile phones) Therefore: Compression of the protocol overhead needed

5. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia General Structure of Header Compressors Two entities: compressor and decompressor Compressor sends initial base Base is used by compressor and decompressor Compressor removes redundancy Decompressor adds removed information Proposed solution differ in a possible feedback channel N N Base Compressor Decompressor Base N*

6. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia IP Header Compression IP HC RFC2507 provides only rudimentary support for UDP with low compression CRTP has problems with high loss rates and delays (bandwidth-delay product) Overall: problems with previous header compression schemes over wireless links

7. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Robust Header Compression (ROHC) RFC3095 General ROHC header compression scheme Single hop and stateful Dynamic state and context changes

8. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Context states: No context: largest ROHC header for context establishment Static context: context for static parts exists Full context: all parts are within the established context Robust Header Compression (ROHC) RFC3095

9. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Robust Header Compression (ROHC) RFC3095 ROHC modes based on feedback availability Unidirectional mode (no feedback) Periodic context state updates Fallback to lower states upon minor changes Bi-directional optimistic mode Decompressor ACKs context changes NACK based context updates triggered by decompressor Bi-directional reliable mode Closest coupling between compressor / decompressor

10. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Methodology Uncorrelated bit errors as recently found for UMTS channels Simulated with and without ROHC implementation O-Mode

11. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Metrics Peak Signal to Noise Ratio (PSNR) for quality comparison Header Compression, total compression, and mean ROHC header size

12. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Testbed Setup

13. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia PSNR Measurements PSNR calculation is standard metric for objective video quality measurements Freezing for lost frames VideoMeter tool for visualization

14. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Netmeter Tool Bandwidth w/o ROHC Bandwidth with ROHC Header compression Overall compression

15. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia ROHC Results Table of Compression

16. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Insights Protocol header compression can be achieved by using ROHC Higher compression ratios for smaller video formats and higher quantization Lower fraction of packets comprised of actual video data (i.e., payload) Lower error probability and state changes within ROHC

17. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia ROHC Results PSNR Figure

18. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Conclusion ROHC is an efficient header compression scheme for multimedia in wireless environments Compression achieved depends on video format and video content Utilization of ROHC for multimedia streaming does not introduce additional losses in terms of perceived video quality (PSNR)

19. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Q/A Thank you! patrick.seeling@asu.edu fitzek@acticom.de reisslein@asu.edu Am Borsigturm 42 13507 Berlin Germany www.acticom.de The only situation we recommend to be wired!

20. Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia Related Work F.H.P. Fitzek, S. Hendrata, and M. Reisslein, "Header Compression Schemes for Wireless Internet Access", in Wireless Internet: Technologies and Applications, Series: Electrical Engineering & Applied Signal Processing Series, 2004 F.H.P. Fitzek, S. Hendrata, P. Seeling and M. Reisslein, "Video Quality Evaluation for Wireless Transmission with Robust Header Compression", Technical Report: acticom-03-003, acticom GmbH, Germany, July, 2003 P. Seeling, F.H.P. Fitzek, and M. Reisslein, "VideoMeter tool for YUV bitstreams", IEEE Network Magazine, software tools for networking, Vol.17, No. 1, January 2003 S. Rein, F.H.P. Fitzek, and M. Reisslein, "Voice Quality Evaluation for Wireless Transmission with ROHC", International Conference on Internet and Multimedia Systems and Applications (IMSA 2003), pages 461-466, August 13-15, 2003, Honolulu, USA