Generalized degrees of freedom and approximate characterization of the capacity region of the interfering multiple-access channel with feedback

在现代无线通信系统中，存在着从接收机向发射机传递信息的可能性，这种可能性被称为反馈。在这个计划中的项目中，研究了反馈对蜂窝系统中一个典型场景的影响，因此称为干扰多址信道（IMAC）。确定性模型和高斯模型都要考虑。该项目的目标是根据IMAC可实现的速率区域描述性能的基本限制。为此，信息理论和信号处理的新方法和工具被应用、开发和结合，这证明了对反馈系统研究中长期开放问题的重新检查。在这些新工具中，人们可以命名为确定性模型，而非对称信令和干扰对准是用于表征/提高网络频谱效率的新方法。从信息论的角度来看，在这种情况下，通过考虑带宽限制和信号处理方面的必要努力，可以获得数据速率方面的净反馈增益。计划的调查将由一个具体的例子来推动，这个例子清楚地表明，从反馈中可以获得显著的性能改进。

In modern wireless communication systems, there exists the possibility of transferring information from the receivers to the transmitters which is referred to as feedback. In this planned project, the impact of feedback on a typical scenario in cellular systems, denoted henceforth as the interfering multiple access channel (IMAC), is studied. Both deterministic and Gaussian models are to be considered. The objective of the project is the characterization of fundamental limits of performance in terms of achievable rate regions for the IMAC. To this end, new methods and tools from information theory and signal processing are applied, developed, and combined, which justify a renewed examination of longstanding open problems in the research on feedback systems. Among these new tools one can name the deterministic model, while asymmetric signaling and interference alignment are new methods which are used to characterize/increase the spectral efficiency of a network. The information theoretic perspective shall reveal, under which conditions a net feedback gain in terms of data rate can be achieved by taking into account bandwidth constraints and the necessary effort in terms of signal processing. The planned investigation will be motivated by a concrete example, which clearly shows that significant performance improvement can be obtained from feedback.