有限反馈的异构蜂窝网络下行链路能效优化方法

Energy-Efficiency Optimization for Downlink of Heterogeneous Cellular Networks with Limited Feedback

研究了在有限反馈约束下的异构蜂窝网络下行链路中与宏蜂窝共存的小蜂窝能量效率最大化问题。其中,宏基站(Macro Base Station,MBS)和小基站(Small Base Station,SBS)通过共享频谱分别向宏用户(Macro User,MU)和小用户(Small User,SU)发送信号。提出了有限反馈和功率带宽联合优化方案来最大限度地提高小蜂窝中所有SU的平均能量效率。由于所构建的目标函数是分式形式并且具有非凸性,采用丁克尔巴赫方法将分式形式化为等价减法形式,并通过增广拉格朗日乘子法求解,提出两层迭代优化算法得到目标函数的最优解。仿真结果表明,相比于传统功率带宽等分配的反馈比特优化方案,所提方案明显地提升了小蜂窝所有SU的平均能量效率。

This paper investigates the problem of energy efficiency maximization for the small cells that coexist with a macro cell in an underlay heterogeneous cellular network with limited feedback.Wherein,the macro base station and the small base station send signals to a macro user and small users respectively by sharing spectrum.We propose a joint optimization scheme of limited feedback and power bandwidth to maximize the average energy efficiency of all SUs in a small cell.Considering the fractional expression and non-convexity of the optimization problem,we converted the objective function in the form of fraction into an equivalent subtrative form via the Dinkelbach’s method,which is solved by the approach of augmented Lagrange multiplier.Furthermore,we propose an effective iterative algorithm to acquire the optimum solution of our formulated problem.Simulation results demonstrate that the suggested scheme greatly improves the average energy efficiency of all SUs in the small cell compared to traditional energy efficiency maximization scheme with equal distribution of power and bandwidth.