Energy efficiency (EE) optimization of joint power allocation (PA) and beamforming (BF) is studied for multiuser distributed multiple-input multiple-output (D-MIMO) systems with maximum ratio combining. Subject to power budget constraints, a non-convex constrained optimization problem is firstly formulated to maximize EE of single-user D-MIMO. We propose a near-optimal joint design scheme with the block coordinate descent method, which has an effective iterative algorithm to find optimal BF for fixed PA, and an iterative algorithm based on the Dinkelbach methods to find optimal PA for fixed BF. We also develop a low-complexity suboptimal joint scheme, which has closed-form BF and PA by maximizing an effective signal-to-noise ratio for fixed PA and a derived EE upper bound for fixed BF, respectively. It has lower complexity than the near-optimal scheme with slight performance loss. With these results, two joint design schemes are developed for multiuser D-MIMO. The first scheme can achieve the best performance, while the second one based on closed-form PA and BF has slight performance loss in comparing to that of the former, but with lower complexity. Simulation results verify the effectiveness of the developed schemes over some existing schemes.

中文翻译：

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多用户分布式 MIMO 系统节能设计的联合功率分配和波束成形

针对具有最大比率组合的多用户分布式多输入多输出 (D-MIMO) 系统，研究了联合功率分配 (PA) 和波束成形 (BF) 的能效 (EE) 优化。受功率预算约束，首先制定了一个非凸约束优化问题，以最大化单用户 D-MIMO 的 EE。我们提出了一种使用块坐标下降法的近最优联合设计方案，该方案具有有效的迭代算法来为固定的 PA 找到最佳的 BF，以及一种基于 Dinkelbach 方法的迭代算法来为固定的 BF 找到最佳的 PA。我们还开发了一种低复杂度的次优联合方案，它通过最大化固定 PA 的有效信噪比和固定 BF 的派生 EE 上限分别具有封闭形式的 BF 和 PA。它比具有轻微性能损失的接近最优方案具有更低的复杂性。根据这些结果，为多用户 D-MIMO 开发了两种联合设计方案。第一种方案可以获得最好的性能，而第二种基于封闭形式的 PA 和 BF 的方案与前者相比性能损失很小，但复杂度较低。仿真结果验证了所开发方案相对于一些现有方案的有效性。