超奈奎斯特通信中基于预编码和信道编码的传输方案研究

As a technology to improve the spectrum efficiency further, faster-than-Nyquist signaling (FTN) has attracted a lot of attention from researchers on the 5G study. By transmitting non-orthogonal signals in time domain and frequency domain, FTN signaling can transmit 30%-100% more data with the same bandwidth and energy. Because of this non-orthogonality, there exists inevitable intersymbol interference (ISI) at the receiver. To remove this ISI, it is unpractical to apply conventional Viterbi algorithm and BCJR algorithm due to the high complexity. Up to now, the research to reduce the complexity mainly focuses on the trellis structure of the ISI, either reducing the number of states or reducing the search path in the trellis. However, the complexity of above methods depends on the size of the ISI trellis. Thus, it cannot be used in the severe ISI scenario. This project aims to reduce the complexity and improve the performance of FTN signaling from a new point of view. First, we propose an ISI cancellation scheme based on pre-coding. The complexity of the proposed scheme is independent of the ISI trellis, which is attractive in the severe ISI scenario. Simulation results show that proposed scheme can improve the performance with a lower complexity. Second, this project aims to apply channel codes to the proposed scheme and design low-complexity and high-performance decoders. Finally, the performance and the achievable rate when applying FTN in the frequency domain and NOMA system will be analyzed.

作为进一步提高频谱有效性的技术，超奈奎斯特通信（FTN）在第五代移动通信的研究中引起了广泛的重视。通过传输非正交信号，FTN可在相同带宽和能量时，多传输30%-100%的数据。然而，在接收端会存在码间干扰（ISI）。在消除上述ISI时，传统的Viterbi和BCJR算法因高复杂度而难以实现。目前降低复杂度的研究主要集中在ISI的网格结构：或减少此网格的状态数；或减少在此网格中的搜索数。然而上述方法的复杂度取决于ISI网格大小，故不适用于严重ISI场景。本项目以全新角度来降低FTN的复杂度并提高其性能。首先，本项目拟提出一种基于预编码和自适应调制的FTN的ISI消除方案。该方案复杂度不取决于ISI的网格，故适用于严重ISI场景。前期仿真表明了该方案的有效性。其次，本项目拟将信道编码应用于该方案，提出低复杂度高性能解码算法。最后，将基于预编码和信道编码的FTN方案应用于频域及非正交接入。

本项目以全新角度研究了超奈奎斯特通信中基于预编码和信道编码的传输方案，用以降低FTN的复杂度并提高其性能。具体本项目提出了一种基于预编码和自适应调制的FTN的ISI消除方案，并将信道编码应用于该方案且提出了低复杂度高性能解码算法，同时将预编码和信道编码的FTN方案应用于频域及非正交接入，这将对FTN在5G中的应用具有潜在的应用价值。另外，基于本项目的进展进一步研究了编码技术在天线领域的应用可能性。目前该项目在国内外权威学术期刊和会议上发表论文共计6篇，其中SCI检索期刊论文3篇，基于本课题研究内容申请发明专利3项。