Integrating coded caching (CC) into multiple-input multiple-output (MIMO) communications may significantly enhance the achievable degrees of freedom (DoF) of the wireless networks. In this paper, we consider a cache-aided MIMO configuration with a CC gain $t$, where a server with $L$ Tx antennas communicates with $K$ users, each with $G$ Rx antennas. In the proposed content-aware MIMO strategy, we carefully adjust the number of users $\Omega$ and the number of parallel streams decoded by each user $\beta$ served in each transmission to maximize the DoF. As a result, we achieve a DoF of ${\max_{\beta, \Omega }}{\Omega \beta}$, where ${\beta \le \mathrm{min}\big(G,\frac{L \binom{\Omega-1}{t}}{1 + (\Omega - t-1)\binom{\Omega-1}{t}}\big)}$. To prove the achievability of the proposed DoF bound, we provide a novel transmission strategy based on the simultaneous unicasting of multiple data streams. In this strategy, the missing data packets are scheduled such that the number of parallel streams per transmission is maximized while the decodability of all useful terms by each target user is guaranteed. Numerical simulations validate the findings, confirming the enhanced DoF and improved performance of the proposed design.

翻译：将编码缓存技术集成到多输入多输出通信系统中，可显著提升无线网络的可达自由度。本文研究具有编码缓存增益$t$的缓存辅助MIMO配置：配备$L$根发射天线的服务器与$K$个用户通信，每个用户配备$G$根接收天线。在所提出的内容感知MIMO策略中，我们通过精细调整每次传输服务的用户数$\Omega$以及每个用户解码的并行流数量$\beta$来最大化自由度。由此获得自由度表达式${\max_{\beta, \Omega }}{\Omega \beta}$，其中${\beta \le \mathrm{min}\big(G,\frac{L \binom{\Omega-1}{t}}{1 + (\Omega - t-1)\binom{\Omega-1}{t}}\big)}$。为证明所提自由度界的可达性，我们提出了一种基于多数据流同步单播的新型传输策略。该策略通过优化缺失数据包的调度方式，在保证每个目标用户可解码所有有效项的前提下，最大化每次传输的并行流数量。数值仿真验证了研究结果，证实了所提设计在自由度提升和性能改善方面的有效性。