Hybrid Multicast-Unicast Streaming over Mobile Networks

Mobile on-demand videos are getting tremendously popular and incurring staggering overhead on cellular networks. Fortunately, next generation cellular networks support video streaming over either unicast or multicast, but how to capitalize both unicast and multicast for optimal on-demand video streaming remains an open question. In this paper, we consider a resource allocation problem that concurrently utilizes unicast/multicast in order to support many more mobile streaming users and minimize the energy consumption of the battery-powered mobile devices. We formulate this problem as a Binary Integer Programming (BIP) problem. We present an optimal algorithm, SCOPT, for this problem. We also develop an efficient heuristic algorithm, SCG, for lower overhead. We conduct detailed packet-level simulations to evaluate the algorithms in LTE networks using OPNET. Our simulation study shows that the proposed algorithms: (i) result in lower energy consumption than multicast-only approach, (ii) scale to many more mobile users than unicast-only approach, and (iii) are more energy efficient with more network bandwidth or fewer videos. In addition, we discuss how our solution can be extended to support Single Frequency Networks in which multiple adjacent base stations operate on the same frequency.