Private:hybrid

Hybrid Multicast-Unicast Multimedia Streaming over 3G/4G Networks

Since the introduction of touch screen and smart phones, the load on wireless networks has dramatically increased. A large portion of this traffic load is due to the increased consumption of mobile video. This trend of consuming more videos on mobile devices is expected to continue and accelerate in the coming few years. This creates a challenge for wireless network operators, because of the limited wireless bandwidth of their networks and the substantial bandwidth requirements for each video session. Thus, some wireless network operators are starting to limit the amount of data that mobile subscribers can consume in order to reduce the load on their networks.

We propose a new method of streaming videos to large-scale subscriber base in a bandwidth and energy efficient manner. Our method uses:

• (i) burst transmission of videos to reduce energy consumption of mobile devices,

• (ii) unicast streaming to serve on-demand requests of videos to individual subscribers,

• (iii) multicast streaming to serve (concurrent) requests of the same videos by many subscribers. Concurrent requests such as news and sports events are supposed to be delivered synchronously (all subscribers receive the same data at the same time).

• (iv) hybrid of unicast and multicast to serve on-demand requests of popular streams. These requests come asynchronously, i.e., subscribers request to watch a popular video clip at different times. The idea is to group requests that come in close time in a multicast session. Some requests may come slightly after the multicast session starts. We create a temporary unicast session for that new session. This unicast session is used to make the new session catch up with the multicast session. That is, the mobile subscriber opens two connections: one unicast and multicast. This idea is used before for Internet video-on-demand streaming systems, and there have been several versions of it, such as Patching, Batching, Pyramid Broadcasting, etc. There is a major difference though: in cellular networks, we transmit videos in bursts to save the energy of mobile devices. Thus, the modeling of the multicast and unicast session will be different in wireless networks than in traditional video-on-demand Internet streaming.

Progress Reports

• 19 March: Report (link to SVN doc). Summary of changes in few lines.

References and Links

• Bradshaw et al., Periodic broadcast and patching services-implementation, measurement and analysis in an internet streaming video testbed
• Xie et.al., Optimizing Patching-based multicast for video-on-demand in wireless mesh networks
• Hua and Xie, A Dynamic Stream Merging Technique for Video-on-Demand Services over Wireless Mesh Access Networks