基于QOSTBC的空间调制多天线下行传输技术研究

大规模MIMO能够提供更高的频谱效率，从而成为5G通信的重要传输技术。然而，在下行大规模MIMO传输中，当发射机无法获知精确的信道信息时，基站和移动台两端不对等的天线数量为系统设计带来了新的挑战。传统的空间调制和空时分组编码虽然能为下行链路提供了射频约减和空间分集，但这些技术均不足以在大规模天线数量下提供高速可靠的无线传输。针对这个问题，本项目旨在提出和完善基于准正交空时分组码的空间调制传输理论，通过挖掘准正交空时码的高谱效和空间调制的稀疏信号特性，实现兼顾频谱效率和分集增益、适应大规模发射天线数量的下行传输。基于上述理论，本项目还将研究低复杂度高性能的信号检测和高效的大规模天线选择方法，从而为下行大规模MIMO提供收发信机优化设计。本项目的研究成果有望为下行大规模MIMO系统提供高速率高可靠的新型传输理论，在后5G未来移动通信中具有良好的应用前景。

Massive multiple-input multiple-output (MIMO) can provide higher spectral efficiency, thus it is considered as an important transmission technology for 5G communications. However, in the downlink MIMO transmission, when the transmitter cannot obtain accurate channel information, the inequality of antennas numbers at both ends of the base station and the mobile station brings new challenges to the system design. Although traditional spatial modulation (SM) and space-time block code (STBC) can provide radio frequency reduction and spatial diversity for the downlink, these technologies are not sufficient to provide high-rate and reliable wireless transmission with massive antennas. To solve this problem, this project aims to propose and improve the quasi-orthogonal space-time block code (QOSTBC) based SM transmission theory. By exploiting the high spectral efficiency of QOSTBC and the signal sparsity of SM, it can achieve both high spectral efficiency and diversity gain, and adapt the downlink transmission for massive MIMO. Based on the above theory, this project will also study low-complexity, high-performance signal detection and efficient massive antenna selection methods to provide transceiver optimization design for downlink massive MIMO. The research results of this project are expected to provide a new high-speed and high-reliability transmission theory for the downlink massive MIMO system, and have a good application prospect in the Beyond-5G future mobile communications.