As intelligent content management of IPTV moves popular material nearer to the end-user, application-layer channel coding schemes, involving the retransmission of extra redundant data, become attractive as a result of the reduced latency. Application-layer, adaptive rateless channel coding is exploited in this paper's scheme to reconstruct streamed video across an IEEE 802.16e (mobile WiMAX) channel. The paper concentrates on the trade-offs in implementing the scheme, showing that exact calculation of the redundant data has the potential to reduce the forward error correction bit-rate overhead. To reduce delay, an appropriate compression rate should also be selected. 1. Introduction The BBC’s iPlayer in the UK [1] has demonstrated the demand for Internet Protocol TV (IPTV) value-added video streaming in the form of content-on-demand and time-shifted TV. However, this service is primarily aimed at asymmetric digital subscriber line (ADSL) receivers and may be ill adapted to mobile wireless broadband delivery. In such broadband wireless networks, including IEEE 802.16e (mobile WiMAX) [2], adverse channel conditions are a concern for video streaming and will become more so as the transition to higher data-rate IEEE 802.16m (WiMAX 2) [3] occurs. The IEEE 802.16e standard provides Turbo coding and hybrid ARQ at the Physical layer with scalable transmission bursts depending on radio frequency (RF) conditions. However, application-layer forward error correction (AL-FEC) [4] is still recommended for IPTV during severe error conditions. This paper demonstrates packet-by-packet adaptive rateless channel coding to guard against burst errors possibly caused by slow and fast fading on a WiMAX channel. The prior IPTV content delivery network (CDN) scheme discussed in [5] was end to end, providing adaptation through a form of FEC simulcast. For severe conditions, it relies on the lower overhead and linear decoding complexity that one form of rateless coding, Raptor codes [6], provides. However, it now seems likely [7] that intelligent content management will result in local caching of frequently requested content. This development enables packet-by-packet adaptive rateless coding, depending on local measurements of channel conditions. Given the reduced latency, it may also be possible to include limited retransmission of extra redundant data, made feasible through rateless channel coding. The iPlayer, as mentioned above, is a simple simulcast service with H.264/AVC (Advanced Video Coding) codec compression [8] and streaming rates available at 500？kbps, 800？kbps, and
References
[1]
“BBC iPlayer growth continues as bbc.co.uk records 29% increase,” 2008, http://www.bbc.co.uk/pressoffice/pressreleases/stories/2008/02_february/20/iplayer.shtml.
[2]
R. Jain, C. So-In, and A. K. Al-Tamimi, “System-level modeling of IEEE 802.16E mobile WiMAX networks,” IEEE Wireless Communications, vol. 15, no. 5, Article ID 4653135, pp. 73–79, 2008.
[3]
S. Ahmadi, Mobile WiMAX: A Systems Approach to Understanding IEEE 802.16m Radio Access Technology, Academic Press, London, UK.
[4]
DVB Blue Book A115—DVB Application Layer FEC Evaluations, 2007, http://www.dvb.org/technology/standards/index.xml.
[5]
M. Luby, T. Stockhammer, and M. Watson, “Application layer FEC In IPTV services,” IEEE Communications Magazine, vol. 46, no. 5, pp. 94–101, 2008.
[6]
A. Shokrollahi, “Raptor codes,” IEEE Transactions on Information Theory, vol. 52, no. 6, pp. 2551–2567, 2006.
[7]
N. Degrande, K. Laevens, and D. de Vleeschauwer, “Increasing the user perceived quality for IPTV services,” IEEE Communications Magazine, vol. 46, no. 2, pp. 94–100, 2008.
[8]
T. Wiegand, G. J. Sullivan, G. Bj？ntegaard, and A. Luthra, “Overview of the H.264/AVC video coding standard,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, no. 7, pp. 560–576, 2003.
[9]
P. Gill, M. Arlitt, Z. Li, and A. Mahanti, “YouTube traffic characterization: a view from the edge,” in Proceedings of the 7th ACM SIGCOMM Internet Measurement Conference (IMC'07), pp. 15–28, October 2007.
[10]
F. Hartung, U. Horn, J. Huschke, M. Kampmann, T. Lohmar, and M. Lundevall, “Delivery of broadcast services in 3G networks,” IEEE Transactions on Broadcasting, vol. 53, no. 1, pp. 188–199, 2007.
[11]
C. Hellge, T. Schierl, J. Huschke, T. Rusert, M. Kampmann, and T. Wiegand, “Graceful degradation in 3GPP MBMS mobile TV services using H.264/AVC temporal scalability,” EURASIP Journal on Wireless Communications and Networking, vol. 2009, 15 pages, 2009.
[12]
S. Mys, P. Lambert, and W. de Neve, “SNR scalability in H.264/AVC using data partitioning,” in Proceedings of the Pacific Rim Conference on Multimedia, pp. 329–338, 2006.
[13]
R. Rouzbeh, M. Fleury, M. Altaf, H. Sammak, and M. Ghanbari, “H.264 video streaming with data-partitioning and growth codes,” in Proceedings of the IEEE International Conference on Image Processing (ICIP '09), pp. 909–912, Egypt, November 2009.
[14]
T. Schierl, S. Johansen, C. Hellge, T. Stockhammer, and T. Wiegand, “Distributed rate-distortion optimization for rateless coded scalable video in mobile ad hoc networks,” in Proceedings of the 14th IEEE International Conference on Image Processing (ICIP '07), pp. 497–500, September 2007.
[15]
S. Ahmad, R. Hamzaoui, and M. Al-Akaidi, “Adaptive unicast video streaming with rateless codes and feedback,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 20, no. 2, Article ID 5229358, pp. 275–285, 2010.
[16]
T. Stockhammer and M. Bystrom, “H.264/AVC data partitioning for mobile video communication,” in Proceedings of the IEEE International Conference on Image Processing (ICIP '04), pp. 545–548, October 2004.
[17]
D. J. C. MacKay, “Fountain codes,” IEE Proceedings: Communications, vol. 152, no. 6, pp. 1062–1068, 2005.
[18]
M. Luby, “LT codes,” in Proceedings of the 34rd Annual IEEE Symposium on Foundations of Computer Science, pp. 271–280, November 2002.
[19]
R. Palanki and J. S. Yedidia, “Rateless codes on noisy channels,” in Proceedings of the International Symposium on Information Theory, p. 37, July 2004.
[20]
S. Wenger, “H.264/AVC over IP,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, no. 7, pp. 645–655, 2003.
[21]
R. M. Schreier and A. Rothermel, “Motion adaptive intra refresh for low-delay video coding,” in Proceedings of the International Conference on Consumer Electronics (ICCE '06), pp. 453–454, January 2006.
[22]
Y. J. Liang, K. El-Maleh, and S. Manjunath, “Upfront intra-refresh decision for low-complexity wireless video telephony,” in Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS '06), pp. 3097–3100, May 2006.
[23]
C. Zhu, Y. K. Wang, M. M. Hannuksela, and H. Li, “Error resilient video coding using redundant pictures,” in Proceedings of the IEEE International Conference on Image Processing (ICIP '06), pp. 801–804, October 2006.
[24]
P. Ferré, D. Agrafiotis, and D. Bull, “A video error resilience redundant slices algorithm and its performance relative to other fixed redundancy schemes,” Image Communication, vol. 25, no. 3, pp. 163–178, 2010.
[25]
M. Zorzi and R. R. Rao, “On the statistics of block errors in bursty channels,” IEEE Transactions on Communications, vol. 45, no. 6, pp. 660–667, 1997.
[26]
C. Jiao, L. Schwiebert, and B. Xu, “On modeling the packet error statistics in bursty channels,” in Proceedings of the IEEE Conference on Local Computer Networks, pp. 534–541, 2002.
[27]
M. Luby, T. Gasiba, T. Stockhammer, and M. Watson, “Reliable multimedia download delivery in cellular broadcast networks,” IEEE Transactions on Broadcasting, vol. 53, no. 1, pp. 235–246, 2007.
[28]
J. Chen, C. C. Wang, F. C. D. Tsai et al., “The design and implementation of WiMAX module for ns-2 simulator,” in Proceedings of the Workshop on ns-2, October 2006.
[29]
Y. J. Liang, J. G. Apostolopoulos, and B. Girod, “Analysis of packet loss for compressed video: effect of burst losses and correlation between error frames,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 18, no. 7, Article ID 4490280, pp. 861–874, 2008.
[30]
“IEEE standard for local and metropolitan area networks. Part 16: air interface for fixed and mobile broadband wireless access systems,” IEEE, p. 802, 2005.
[31]
C. So-In, R. Jain, and A. K. Tamimi, “Capacity evaluation for IEEE 802.16e mobile WiMAX,” Journal of Computer Systems, Networks, and Communications, 12 pages, 2010.
[32]
J. Klaue, B. Rathke, and A. Wolisz, “EvalVid—a framework for video transmission and quality evaluation,” in Proceedings of the International Conference on Modeling Techniques and Tools for Computer Performance, pp. 255–272, 2003.
