Stochastic Cooperative Multicast Scheduling for Cache-Enabled and Green 5G Networks

Caching has advantages in mitigating the backhaul data traffic and multicast is able to satisfy multiple identical requests by a multicast stream, which are the two most promising technologies to realize tremendous data transmission in 5G networks. However, many studies focus on cooperative caching but ignore the problem that what contents to multicast for a given caching status by cooperation between base stations (BSs). In this paper, we consider the cooperative multicast scheduling problem in cache-enabled 5G networks to satisfy user demands while minimizing the energy consumption. We propose a novel pending request queue model and transform the cooperative multicast scheduling problem into a Lyapunov stochastic optimization problem that can be calculated on-line. By analyzing properties of the problem, we proposed an on-line centralized algorithm to obtain the optimal strategy. Motivated by practical deployment, we further propose a distributed algorithm which has similar performance and lower complexity. Extensive simulations have been conducted to verify that our algorithms have better performance than several state-of-art algorithms, including both energy consumption and delay.