Massive MIMO Systems for Communication and Localization

多天线技术是当前和未来无线通信和定位系统的关键要素。传统上，为多输入多输出(MIMO)通信和定位系统设想的天线数量(每个包括一个独立的收发器)一直被限制在相对较小的数量，例如20个或更少。然而，最近有研究表明，如果基站的天线数量增加到数百甚至数千个，则多用户MIMO通信系统表现出一些良好的特性，从而产生所谓的大规模或大规模MIMO系统。尽管在过去的两年里，大量的理论研究致力于大规模MIMO通信系统，但在大规模MIMO通信系统能够在实践中部署之前，在信号处理和信号设计方面仍然需要显著的改进。此外，虽然预计在大规模MIMO通信系统中观察到的收益会延续到本地化问题，但这个问题还没有被研究。此外，由于小规模的MIMO系统架构不能简单地扩展到大规模的MIMO系统，因此，大量的天线和相干收发机的数量以及巨大的预期数据速率需要新的电路和系统设计方法来实现大规模MIMO系统。此外，对常用的MIMO系统和信道模型的有效性提出了质疑。因此，为了得到有意义的结果，现实环境中的信道测量是必要的，并且必须验证并可能适当地修改硬件损伤的现有模型。这些考虑强调了为优化和验证理论结果而建立灵活的MIMO试验台的必要性。因此，在这个项目中，我们将对大规模的MIMO系统设计采取全面的方法，将我们在信号处理和通信(数字通信研究所，IDC，Schober)、本地化和天线设计(微波和光子学研究所，LHFT，Vossiek)以及收发器设计和实现(技术电子研究所，LTE，Weigel)方面的集体专业知识结合在一起。该项目有以下四个具体目标：1)开发计算高效、安全、健壮和高性能的预编码和检测策略；2)设计具有非常稳定的相位特性的天线；3)开发新的同步协议、多径分离算法和定位技术。4)能够实现大规模MIMO系统的电路和系统架构的开发。目标1)-4)将通过在大型MIMO试验台上对所开发的算法、电路和系统架构进行理论研究和实现/验证来实现。

Multiple-antenna technology is a key element of current and future wireless communication and localization systems. Traditionally, the number of antennas (each including an independent transceiver) envisioned for multiple-input multiple-output (MIMO) communication and localization systems has been limited to a comparatively small number, say 20 or less. However, recently, it has been shown that multiuser MIMO communication systems exhibit several favorable properties if the number of antennas at the base station is increased to hundreds or even thousands of antennas, giving rise to so-called large-scale or massive MIMO systems. Although a large amount of theoretical research has been dedicated to massive MIMO communication systems in the past two years, significant improvements in signal processing and signal design are still necessary before massive MIMO communication systems can be deployed in practice. Furthermore, while it is expected that the gains observed in massive MIMO communication systems carry over to localization problems, this issue has not been investigated yet. Moreover, the large number of antennas and coherent transceivers, and the large expected data rates require new approaches to circuit and system design for implementation of massive MIMO systems, since small-scale MIMO system architecures cannot simply be scaled up to massive MIMO systems. Furthermore, the validity of the commonly used MIMO system and channel models are put in question. Therefore, to arrive at meaningful results, channel measurements in realistic environments are necessary and existing models for hardware impairments have to be verified and possibly suitably modified. These considerations underline the necessity of a flexible MIMO testbed for optimization and verification of theoretical results. Thus, in this project, we will take a holistic approach to massive MIMO system design bringing together our collective expertise in signal processing and communication (Institute for Digital Communications, IDC, Schober), localization and antenna design (Institute for Microwaves and Photonics, LHFT, Vossiek), and transceiver design and implementation (Institute for Technical Electronics, LTE, Weigel). The proposed project has the following four specific objectives: 1) Development of computationally efficient, secure, robust, and high performance precoding and detection strategies.2) Design of antennas with very stable phase characteristic.3) Development of novel synchronization protocols, multipath separation algorithms, and localization techniques. 4) Development of circuit and system architectures enabling the implementation of massive MIMO systems.Objectives 1)-4) will be achieved through both theoretical research and implementation/verification of the developed algorithms, circuits, and system architectures in a massive MIMO testbed.