Energy-efficient multicasting of multiview 3D videos to mobile devices

Multicasting multiple video streams over wireless broadband access networks enables the delivery of multimedia content to large-scale user communities in a cost-efficient manner. Three dimensional (3D) videos are the next natural step in the evolution of digital media technologies. In order to provide 3D perception, 3D video streams contain one or more views that greatly increase their bandwidth requirements. Due to the limited channel capacity and variable bit rate of the videos, multicasting multiple 3D videos over wireless broadband networks is a challenging problem. In this article, we consider a 4G wireless access network in which a number of 3D videos represented in two-view plus depth format and encoded using scalable video coders are multicast. We formulate the optimal 3D video multicasting problem to maximize the quality of rendered virtual views on the receivers' displays. We show that this problem is NP-complete and present a polynomial time approximation algorithm to solve it. We then extend the proposed algorithm to efficiently schedule the transmission of the chosen substreams from each video in order to maximize the power saving on the mobile receivers. Our simulation-based experimental results show that our algorithm provides solutions that are within 0.3 dB of the optimal solutions while satisfying real-time requirements of multicast systems. In addition, our algorithm results in an average power consumption reduction of 86%.