基于能效最优准则的双跳中继网络功率分配算法

Power allocation algorithms in two-hop relaying networks based on optimal energy efficiency

针对单天线多跳系统中的资源分配策略进行了研究,重点研究了基于能效最优的功率分配算法。所提算法以系统能效最大化为设计目标,以满足指定的系统服务质量(QoS,quality of service)为约束条件,建立了以源节点和中继节点发射功率为设计变量的数学优化模型。通过大信噪比区间近似等效,将原始的非凸优化问题转化为凸优化问题。再利用拉格朗日对偶函数凸优化算法,并借助于LambertW函数,最终得到一种功率分配方案的闭合形式解,避免了采用交替迭代方法来求解最优化问题。相比传统以系统频谱效率最大化为目标的算法,所提算法能更好地提升系统整体能效,同时降低了功率分配算法的复杂度。

The joint source-relay power allocation issue in green dual-hop single antenna relaying systems was investigated from the energy efficiency point of view. By considering a practical power consumption model, the optimal algorithm in order to satisfy the constraints of system quality of service was proposed. The non-convex problem was converted into the convex problem through high power approximation and then the highly complicated optimization problem was solved by deliberately manipulating the Lagrangian function using the properties of the Lambert function. The optimal transmit power of the source and that of the relay are derived in the form of analytical expressions based on the maximization of EE with a guarantee of the required spectral efficiency（SE）. It is shown that the optimal relay-to-source power ratio is adaptive to the ratio of the instantaneous two-hop channel gains. Numerical simulations have illustrated the effectiveness of proposed scheme.