Energy Efficiency Optimization with Simultaneous Wireless Information and Power Transfer in MIMO Broadcast Channels
Energy Efficiency Optimization with Simultaneous Wireless Information and Power Transfer in MIMO Broadcast Channels
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发表时间：
2016-11
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通讯作者：
Jie Tang;D. So;Arman Shojaeifard;Kai‐Kit Wong
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作者：
Jie Tang;D. So;Arman Shojaeifard;Kai‐Kit Wong
同步无线信息和电力传输 (SWIPT) 预计将在第五代 (5G) 及其他通信系统中得到广泛应用。在本文中，我们解决了具有时间切换（TS）接收器设计的 SWIPT 多输入多输出广播信道（MIMO-BC）的能效（EE）优化问题。我们的目标是最大化系统的 EE，同时满足每个用户的最大发射功率和最小收集能量方面的某些限制。优化变量（即传输协方差矩阵和 TS 比率）的耦合导致了非凸 EE 问题，因此很难直接求解。因此，我们将原始的具有多个约束的最大化问题转化为具有单个约束和多个辅助变量的最小-最大问题。我们提出了一个双内/外层资源分配框架来解决这个问题。对于内层，我们调用扩展的基于 SWIPT 的 BC 多址接入信道（MAC）对偶方法，并在固定辅助变量下提供两种迭代资源分配方案来解决双 MAC 问题。然后为外层提出了次梯度搜索方案以获得最优辅助变量。数值结果证实了所提出算法的有效性，并表明采用所提出的基于扩展 BC-MAC 对偶性的算法可以在 EE 方面实现显着的性能增益。
Simultaneous wireless information and power transfer (SWIPT) is anticipated to have great applications in fifth-generation (5G) and beyond communication systems. In this paper, we address the energy efficiency (EE) optimization problem for SWIPT multiple-input multiple-output broadcast channel (MIMO-BC) with time-switching (TS) receiver design. Our aim is to maximize the EE of the system whilst satisfying certain constraints in terms of maximum transmit power and minimum harvested energy per user. The coupling of the optimization variables, namely, transmit covariance matrices and TS ratios, leads to a EE problem which is non-convex, and hence very difficult to solve directly. Hence, we transform the original maximization problem with multiple constraints into a min-max problem with a single constraint and multiple auxiliary variables. We propose a dual inner/outer layer resource allocation framework to tackle the problem. For the inner-layer, we invoke an extended SWIPT-based BC-multiple access channel (MAC) duality approach and provide two iterative resource allocation schemes under fixed auxiliary variables for solving the dual MAC problem. A sub-gradient searching scheme is then proposed for the outer-layer in order to obtain the optimal auxiliary variables. Numerical results confirm the effectiveness of the proposed algorithms and illustrate that significant performance gain in terms of EE can be achieved by adopting the proposed extended BC-MAC duality-based algorithm.