Interference alignment aided by non-regenerative relays

传统上，在无线通信网络中，中继器被用来扩展范围，即在噪声受限的情况下提高性能。与此形成对比的是，我们将重点关注干扰受限的场景。在这种情况下，继电器可用于遵循干扰对齐的思想来减少干扰。所研究的场景由几对想要相互通信的节点组成。此外，还有几个中继器帮助通信。尤其要考虑双向交流。在这种情况下，遵循到目前为止还没有结合干扰对齐来考虑的双向中继的想法，可能会显著提高性能。每个节点可以配备几个天线，但实际上中继处的天线数量太少，无法成功解码所有接收到的信息。为此，我们假定为线性、非再生式继电器。除了确定自由度之外，关于所需的中继器和中继器天线的数量、中继器的信号处理技术以及实现干扰对齐的节点的预编码的问题将在该项目中得到回答。此外，还将进行数值性能评估，以帮助改进算法，而不是纯干扰受限的场景，而是具有显著噪声的场景。这两个项目合作伙伴将从这一场景的两个特殊情况开始研究具有多个天线的多个中继器的一般情况。达姆施塔特理工学院的起点将是具有多个天线的单个中继器的场景，从而实现中继器的联合信号处理，而罗斯托克大学将从多个中继器的场景开始，每个中继器都有一个天线。

Traditionally, relays are used for range extension in radio communication networks, i.e., for improving the performance in noise limited scenarios. In contrast to this, we will focus on interference limited scenarios. In such scenarios, relays can be used for interference reduction following the ideas of interference alignment. The investigated scenario consists of several pairs of nodes which want to communicate with each other. Furthermore, there are several relays aiding the communication. Especially bidirectional communication shall be considered. In this case, significant performance improvements are possible following the ideas of two way relaying which up to now have not been considered in conjunction with interference alignment. Each node may be equipped with several antennas, but realistically the number of antennas at the relays will be too small to successfully decode all the received information. For this reason we assume linear, non regenerative relays. Going beyond determining the degrees of freedom, questions concerning the required number of relays and relay antennas, the signal processing techniques for the relays and the precoding at the nodes for achieving interference alignment will be answered within the project. Also, numerical performance evaluations helping the improvement of the algorithms for not purely interference limited scenarios, but with significant noise will be carried out. The two project partners will start their research towards the general case of multiple relays with multiple antennas from two special cases of this scenario. The starting point for Technische Universität Darmstadt will be a scenario with a single relay with multiple antennas enabling a joint signal processing at the relay whereas Universität Rostock will start with a scenario with many relays with a single antenna each.