In this paper, a power saving scheme is investigated for macrocell-assisted small cell networks in the downlink, in which small cells are selected to stay in sleep or wake-up modes in order to mitigate excessive power consumption and the small cells operating in the sleep mode are eligible to off-load their served users to the macrocell to preserve communications. By taking the dynamics of user arrival into account, we attempt to minimize the average total power consumption of the network, which depends on several network parameters like power consumption of base stations, available bandwidth, user load in the cells, cell size, user rate requirement, rate outage probability and noise power density, while ensuring the average number of dropping off-loaded users to a satisfactory level. The design problem is then formulated as a constrained Markov decision process and solved via linear programming. A randomized strategy is proposed to accomplish the optimal sleep/wake-up policy for small cells. Simulation results confirm the effectiveness of the proposed scheme, as compared with the one without adopting sleep/wake-up mechanisms, and help us to capture the impact of the network parameters on the entire power saving.

在本文中，针对下行链路中的宏蜂窝辅助小蜂窝网络，研究了一种节能方案，在该方案中，选择小蜂窝以保持睡眠或唤醒模式以减轻过多的功耗，并且小蜂窝在网络中运行。睡眠模式有资格将其服务的用户卸载到宏小区以保留通信。通过考虑用户到达的动态，我们尝试最小化网络的平均总功耗，这取决于几个网络参数，例如基站的功耗，可用带宽，小区中的用户负载，小区大小，用户速率要求，速率中断概率和噪声功率密度，同时确保将卸载用户的平均数量降低到令人满意的水平。然后，将设计问题公式化为受约束的Markov决策过程，并通过线性规划解决。提出了一种随机策略来实现小型小区的最佳睡眠/唤醒策略。与不采用睡眠/唤醒机制的方案相比，仿真结果证实了该方案的有效性，并有助于我们捕获网络参数对整个节电的影响。