An Efficient Multicast Scheme for Live Streaming Services in SC-PTM

Live streaming applications over wireless mobile networks have increased dramatically in recent years. In most current systems, the media center is capable of providing multiple streams of different qualities and each individual viewer selects its own stream based on channel condition and/or other considerations. This may result in inefficient use of radio resource. In this paper, we propose to let evolved node B, which has the channel conditions of all viewers, decide which streams should be delivered so that the total throughput is maximized, subject to the constraints that every viewer can successfully decode at least one stream and the radio resource consumed is under a pre-determined threshold. For a system that has many possible modulation and coding schemes, it requires huge computational complexity to obtain the optimum solution. We present a greedy algorithm which tends to find a solution that allows more viewers to decode higher quality streams. Simulation results show that the total throughputs achieved by the greedy algorithm for various scenarios are close to those of the optimum solutions.