云无线接入网络的下行链路能效的优化

在下行云接入网络(C-RANs)中，核心网络内基站处理单元(BBU)通过前向回传线路向远端无线电头端(RRH)传输数据，然后RRHs通过无线接入链路转发数据。目前，C-RANs的下行链路的能效是C-RANs的研究热点。为此，对C-RANs下行链路能效进行研究，其目的在于最大下行链路的能效。通过对联合用户分配(UA)、RRH激活、数据率分配和信号预编码约束，建立能效最大化表述式，再利用基于逐次凸二次规划的迭代算法求解混合整数非线性问题。仿真结果表明，提出的联合优化设计提高了C-RANs的能效。

Energy efficient based design for downlink cloud radio access networks

In downlink Cloud Radio Access Network(C-RANs), the data is transferred from a Base Band Unit(BBU) in the core network to several remote radio heads via a set of edge routers over capacity-limited fronthaul links. The remote radio heads then send the received signals to their users via radio access links. Now, energy efficiency of C-RANs is a topic issue. Therefore, the general downlink of C-RANs is studied in order to maximize the network energy efficiency by jointly optimizing User Association(UA), Radio Remote Head(RRH) activation, data rate allocation and signal precoding. By employing the successive convex quadratic programming framework, an iterative algorithm is proposed to solve the challenging mixed-integer nonlinear problem formulation. Simulation results show that the proposed joint optimization approach significantly improves the energy efficiency.