Massive MIMO Ultra-Efficient Transmission

利用很高的频谱利用率，可以在高载波频率和大带宽下实现100Gbit/S以上的无线通信。在这个项目中，将考虑在57-63 GHz的频率范围和15~bit/S/Hz的频谱效率，使用发射端和接收端都有100个以上天线的多天线系统(多输入多输出，MIMO)。由于6 GHz的大带宽，必须提供一种非常高效和简单的基带信号处理技术。例如，对8个并行空间复用数据流进行QPSK调制就足以实现高达16~bit/S/Hz的频谱效率，理论上，可实现的频谱效率分别与发射端NT和接收端NR处的最小天线数成线性关系。因此，传输最小Nt，Nr个并行空间数据流是可能的。然而，在大型天线阵的实现中，可能会出现以下两种影响并限制理论结果：天线的空间相关性和耦合。此外，在大规模MIMO通信系统的发射和接收侧同时操作数百个天线(包括RF前端)并不节能。因此，需要一种新的设计方法。这个项目的目的是从根本上研究上面提出的系统的可行性。由此，从高频技术的场论和传播模型出发，将空间相关和天线耦合的统一模型归纳为信号处理和信息论中的随机MIMO信道矩阵。此外，还将考虑到信道、天线特性、空间、时间和频率域中的可用信号处理能力以及信道信息，得出目标场景中可实现的带宽效率的基本极限。这是利用随机矩阵理论和优化理论的方法来实现的。此外，还将在57-63~GHz的频率范围内进行测量，以建立随机信道和天线模型。现场模拟将提供整个天线阵列单元之间耦合的真实模型。最后，将使用理论结果、测量和模拟数据来建议系统设计，该系统设计将提供以下特征：用于大规模MIMO系统的创新天线设计、达到15~bit/S/Hz的带宽效率的最优和次最优能量效率收发机设计、使用新设计的信道测量和可达到速率的验证、通过数据传输的实际验证和使用离线数据处理的接收器侧误码率评估。总之，该项目将为大规模MIMO系统的基本极限提供理论上的贡献，并为100Gbit/S无线数据传输提供一种实用的设计。

Wireless communications with more than 100~Gbit/s can be achieved by a very high spectral efficiency, at high carrier frequencies and large bandwidths. In this project, a frequency range of 57--63~GHz and a spectral efficiency of 15~bit/s/Hz using multi-antenna systems with more than 100 antennas at both the transmitter and the receiver (multiple-input multiple-output, MIMO) will be considered. Due to the large bandwidth of 6~GHz a very efficient and simple baseband signal processing technique has to be provided. For example, QPSK modulation on eight parallel spatial multiplexed data streams is sufficient to realize a spectral efficiency of up to 16~bit/s/Hz.In theory, the achievable spectral efficiency scales linearly with the minimum number of antennas at the transmitter nT and the receiver nR, respectively. Hence, a transmission of minimum nT,nR parallel spatial data streams is possible. However, in the implementation of large antenna arrays the following two effects can occur and limit the theoretical result: spatial correlation and coupling of the antennas. Moreover, operating hundreds of antennas simultaneously including the RF frontend at the transmit and receive side of a massive MIMO communication system is not energy efficient. Consequently, a novel design approach is required.This project is intended to fundamentally investigate the feasibility of a system as proposed above. Thereto, a unified model for the spatial correlation and the antenna coupling is going to be induced from field theory and propagation modeling of high frequency technology to stochastic MIMO channel matrices for signal processing and information theory. Also, fundamental limits of the achievable bandwidth efficiency in the target scenario will be derived, taking into account the channel, the antenna characteristics, the available signal processing capabilities in the space, time, and frequency domain, and the channel information. This is achieved using methods of the random matrix theory and the majorization theory. Further, measurements will be taken in the frequency range 57--63~GHz to develop a stochastic channel and antenna model. Field simulations will provide a realistic model of the coupling between the elements of the entire antenna array.Finally, theoretical results, measured and simulated data are going to be used to suggest a system design that provides the following features: an innovative antenna design for massive MIMO systems, an optimal and sub-optimal energy-efficient transceiver design that achieves a bandwidth efficiency of 15~Bit/s/Hz, channel measurements with the new designs and verification of achievable rates, practical validation by data transmission and receiver side bit error rate evaluation using an offline data processing.Altogether, this project will provide both a theoretical contribution to the fundamental limits of massive MIMO systems and a practical design for the 100~Gbit/s wireless data transmission.