We consider the extra degree of freedom offered by the rotation of the reconfigurable intelligent surface (RIS) plane and investigate its potential in improving the performance of RIS-assisted wireless communication systems. By considering radiation pattern modeling at all involved nodes, we first derive the composite channel gain and present a closed-form upper bound for the system ergodic capacity over cascade Rician fading channels. Then, we reconstruct the composite channel gain by taking the rotations at the RIS plane, transmit antenna, and receive antenna into account, and extract the optimal rotation angles after investigating their impacts on the capacity. Moreover, we present a location-dependent expression of the ergodic capacity and investigate the RIS deployment strategy, i.e. the joint rotation adjustment and location selection. Finally, simulation results verify the accuracy of the theoretical analyses and deployment strategy. Although the RIS location has a big impact on the performance, our results showcase that the RIS rotation plays a more important role. In other words, we can obtain a considerable improvement by properly rotating the RIS rather than moving it over a wide area. For instance, we can achieve more than 200\% performance improvement through rotating the RIS by 42.14$^{\circ}$, while an 150\% improvement is obtained by shifting the RIS over 400 meters.

翻译：我们考虑了可重新配置的智能表面(RIS)平面的旋转所提供的额外自由程度,并调查了它改善RIS辅助无线通信系统性能的潜力。我们首先考虑在所有有关节点上建模辐射模式,首先从混合频道获得,然后提出一个封闭式的顶端,以系统机容量超过级联里西亚淡化频道。然后,我们通过在RIS平面上进行旋转、传输天线和接收天线来重建混合频道的收益,并在调查其对能力的影响后抽出最佳的旋转角度。此外,我们展示了依赖位置的ERIS能力的表现,并调查了RIS部署战略,即联合轮调调整和地点选择。最后,模拟结果验证了理论分析和部署战略的准确性。虽然RIS的位置对性能有很大影响,但我们的结果显示RIS的旋转起着更为重要的作用。换换换天线比移动广的区域要好得多。例如,我们可以通过移动RIS系统来超过200美元,而通过移动RIS每米改进150美元。