Massive MIMO Ultra-Efficient Transmission

在高载波频率和大带宽下，可以通过非常高的频谱效率实现超过100 Gbit/s的无线通信。在本项目中，将考虑使用在发射机和接收机处均具有100个以上天线的多天线系统（多输入多输出，MIMO）的57- 63 GHz的频率范围和15 bit/s/Hz的频谱效率。由于6~GHz的大带宽，必须提供一种非常有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的QPSK调制足以实现高达16比特/s/Hz的频谱效率。理论上，可实现的频谱效率分别与发射机处的最小天线数目nT和接收机处的最小天线数目nR成线性比例。因此，最小nT、nR并行空间数据流的传输是可能的。然而，在大型天线阵列的实现中，可能发生以下两种效应并限制理论结果：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包括RF前端的数百个天线不是能量高效的。因此，需要一种新的设计方法。本项目旨在从根本上研究上述系统的可行性。为此，从高频技术的场论和传播模型到信号处理和信息论的随机MIMO信道矩阵，将空间相关性和天线耦合统一起来。此外，在目标场景中可实现的带宽效率的基本限制将被导出，考虑到信道，天线特性，在空间，时间和频率域中的可用信号处理能力，以及信道信息。这是使用随机矩阵理论和优控理论的方法来实现的。此外，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。场模拟将提供整个天线阵列元件之间耦合的真实模型。最后，理论结果、测量和模拟数据将用于建议具有以下特征的系统设计：一种用于大规模MIMO系统的创新天线设计，一种最优和次优节能收发器设计，可实现15比特/秒/赫兹的带宽效率，信道测量与新的设计和验证可达到的速率，实际验证数据传输和接收端的误码率评估使用离线数据处理，总的来说，这个项目将提供大规模MIMO系统的基本限制的理论贡献和100~Gbit/s的无线数据传输的实际设计。

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.