论文标题
在主动RIS辅助MIMO干扰通道的DOF上，具有任意天线配置：RIS何时会有所帮助？
On DoF of Active RIS-Assisted MIMO Interference Channel with Arbitrary Antenna Configurations: When Will RIS Help?
论文作者
论文摘要
活跃的可重构智能表面（RIS）已被证明能够增强两用户多输入多输出（MIMO）干扰通道（IC）的自由度总和（DOF），每个发射器和接收器都具有相等数量的天线。但是，对于任何数量的接收和传输天线，活动RI的何时何时以及如何帮助提高总和仍然不清楚。本文研究了具有任意天线构型的主动RIS辅助两用户MIMO IC的总和。特别是，将RIS波束形成，传输零式和干扰解码集成在一起以解决干扰问题。为了最大程度地提高可实现的总和，整数优化问题被制定，以优化消除干扰链接的数量，通过RIS波束形成。结果，派生可实现的总和可以高于两用户mimo ic的总和，从而导致RIS增益。此外，RIS增益的足够条件是作为RIS元素数量与天线构型之间的关系。
An active reconfigurable intelligent surface (RIS) has been shown to be able to enhance the sum-of-degrees-of-freedom (DoF) of a two-user multiple-input multiple-output (MIMO) interference channel (IC) with equal number of antennas at each transmitter and receiver. However, for any number of receive and transmit antennas, when and how an active RIS can help to improve the sum-DoF are still unclear. This paper studies the sum-DoF of an active RIS-assisted two-user MIMO IC with arbitrary antenna configurations. In particular, RIS beamforming, transmit zero-forcing, and interference decoding are integrated together to combat the interference problem. In order to maximize the achievable sum-DoF, an integer optimization problem is formulated to optimize the number of eliminating interference links by RIS beamforming. As a result, the derived achievable sum-DoF can be higher than the sum-DoF of two-user MIMO IC, leading to a RIS gain. Furthermore, a sufficient condition of the RIS gain is given as the relationship between the number of RIS elements and the antenna configuration.
