With practical finite alphabet inputs, usually the throughput of a practical communication system cannot reach the capacity based on assumption of Gaussian inputs. In this paper, we study the resource allocation strategy for multiple-input multiple-output (MIMO) full-duplex backscatter assisted wireless-powered communication network (FD-BAWPCN) with finite alphabet inputs, to maximize the sum-throughput. Firstly, we propose a gradient-based resource allocation strategy (GBRA), which alternately optimizes the precoder and time allocation based on the two-block alternating direction method of multipliers (ADMM). Secondly, to reduce the computational complexity and improve the feasibility of the strategy in practical applications, we further propose a codebook-based resource allocation strategy (CBRA), which can run more than three orders of magnitude faster than GBRA at the expense of a small sum-rate degradation. Then, the performance of the full-duplex (FD) and half-duplex (HD) system with or without backscatter assistance using GBRA are compared and analyzed. Numerical results demonstrate that the GBRA strategy has great robustness under various conditions but suffers a high computational complexity, and the CBRA strategy is effective and converges speedily.

中文翻译：

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具有有限字母输入的MIMO全双工反向散射辅助无线通信网络的资源分配

对于实际的有限字母输入，通常，基于高斯输入的假设，实际通信系统的吞吐量无法达到容量。在本文中，我们研究了有限字母输入的多输入多输出（MIMO）全双工反向散射辅助无线通信网络（FD-BAWPCN）的资源分配策略，以最大化总吞吐量。首先，我们提出了一种基于梯度的资源分配策略（GBRA），该策略基于乘数的两块交替方向法（ADMM）交替优化预编码器和时间分配。其次，为了降低计算复杂度并提高该策略在实际应用中的可行性，我们进一步提出了一种基于码本的资源分配策略（CBRA），它的运行速度比GBRA快三个数量级以上，但代价是总和速率下降很小。然后，对使用GBRA进行或不进行反向散射辅助的全双工（FD）和半双工（HD）系统的性能进行比较和分析。数值结果表明，GBRA策略在各种条件下均具有较强的鲁棒性，但计算复杂度较高，CBRA策略有效且收敛迅速。