Efficient architecture for IPTV service in emerging broadband access networks.

摘要

As competition in telecom market is increasing, the demand for new revenue sources increases. In Internet Protocol Television (IPTV) service, television and other forms of video services are carried by Internet Protocol, or more generally by packet switching. IPTV is a promising service which can provide interactive triple play service (voice, video, and data). The telecom industry is preparing for this service and increasing its investment for emerging broadband access networks such as FTTX (Fiber-to-the-X, where X = H (home), C (curb), P (premises), B (building), etc.). Video-on-Demand (VoD), which is currently in the deployment stage, is a frontrunner in IPTV service, and it is attracting a lot of research attention.;In this dissertation, we study several VoD topics, focusing on efficient bandwidth-saving streaming mechanisms between VoD servers and customers: namely batching, patching, stream merging, and broadcasting. We also consider other factors related to the VoD service: namely VoD traffic model and video popularity. Recent trends show that these streaming schemes can be combined with one another to achieve better efficiency, and they can be enhanced to support more interactive functions. We introduce the principles for VCR support in multicast schemes, and we then consider interactive VCR support mechanisms in multicast streaming schemes.;Three important factors are required for efficient VoD streaming: (1) an efficient streaming scheme for bandwidth savings, (2) optimal use of deployed network bandwidth, and (3) proactive use of user storage. Considering these factors, we propose several efficient streaming algorithms. First, to attain goals (1) and (2), adaptive streaming algorithms, called Video Adaptive STreaming (VAST) and Video Greedy Adaptive STreaming (VGAST), are proposed. Second, to achieve goals (1), (2), and (3) together, we propose Video Greedy Adaptive STreaming with Proactive Buffering (VGAST-PB) algorithm which is based on VGAST but proactively stores some of the popular videos in user buffers during less busy time.;In patching schemes, deciding on the proper patching window can save on the required bandwidth. We review the patching scheme and analyze the optimum patching window and the total required bandwidth. First, we propose a modified optimum patching window to increase the accuracy when multicast streams are transmitted at playback speed. Second, we calculate the optimum patching window and required bandwidth when the speed of multicast streams is multiple times of the playback speed, and we analyze the effects of multicast streaming speed in the aspect of bandwidth usage. Third, we review the VCR functions and mechanisms to support VCR functions in patching, and we obtain the minimum required bandwidth by calculating the optimum patching window considering VCR action support for both cases: implementing VCR functions in playback speed streaming and implementing VCR functions in higher-speed streaming.;Batching is another bandwidth-saving streaming technique. We propose a Popularity-based OLT Batching (POB) scheme for VoD service, which uses Maximum Factored Queue Length (MFQL)-oriented strategy, but with different queue-selection algorithm by using limited number of queues at the OLT. In POB, the number of parallel queues does not increase proportionately to the number of served videos, but POB shows better performance in aspects such as the number of canceled request.