The Cornell team focuses on the following four directions for improving video transport over wireless systems:
- Coding for Wireless Video-on-Demand. One of the greatest inefficiencies of existing commercial wireless networks is that they treat all video multicasts as separate unicasts, mainly because it is on-demand, i.e., the receivers are asynchronous. We use coding and stochastic control techniques to enable base stations to broadcast information that is simultaneously useful to all receivers in the multicast, regardless of viewing start time, channel quality, distortion tolerance, and existing knowledge of future frames.
- Protocols for Exploiting Network Heterogeneity. The proliferation of different wireless access technologies, together with the growing number of multi-radio wireless devices suggest that the opportunistic utilization of multiple connections at the users (i.e., network heterogeneity) can be an effective solution to the phenomenal growth of traffic demand in wireless networks. We study the fundamental limits at which network heterogeneity improves video transport over wireless networks and develop optimal protocols to exploit it.
- Speculative Video Streaming. The video content requested by users can often be predicted based on their location and past viewing habits. We study ways of predicting the location and timing of future requests and speculatively moving the content within the network to be near to the point of consumption.
- Quality-Aware Routing using Dynamic Side Information. Existing video streaming protocols are limited to making scheduling decisions based upon either packet priorities or upon limited and static side information in the video packets. We develop dynamic side information that is stored as state information in network nodes and that is modified appropriately as the data travels through the network, as well as intelligent routing and scheduling algorithms to exploit this side information.
[J/C-1] Sina Lashgari and A. Salman Avestimehr, "Timely Throughput of Heterogeneous Wireless Networks: Fundamental Limits and Algorithms" , submitted to IEEE Transactions on Information Theory, January 2012.
[J/C-2] Sina Lashgari and A. Salman Avestimehr, "Approximating the Timely Throughput of Heterogeneous Wireless Networks", submitted to IEEE International Symposium on Information Theory 2012.
[J/C-3] S. Lashgari and A. S. Avestimehr, "Approximating the Timely Throughput Capacity of Wireless Networks", to be submitted to IEEE Transactions on Wireless Communications.
[M-1] Pegah Aalami, "Optimal Strategies for Splitting Video Traffic in Heterogeneous Networks", MEng final project report, May 2011. Supervised by A. S. Avestimehr.
[M-2] Karuna Lalchand Rohra, "Rate-distortion performance of SVC compared to single layer H.264/AVC coding", MEng final project report, May 2011. Supervised by S. Hemami.