Non-Orthogonal Transmission Techniques for Next-Generation Communications Systems

下一代无线系统将具有新颖的用例，需要终端用户的千兆体验来支持数据密集型无线应用（如4K流媒体），并需要严格的能耗来支持预期的大规模连接。这些要求对现有无线系统基础设施提出了若干技术挑战，需要探索新技术来提高下一代无线系统的频谱效率（SE）和能源效率（EE）。传统的通信系统遵循奈奎斯特定理，在时域和/或频域使用正交脉冲进行传输。这简化了发射器和接收器的设计；然而，这也限制了性能。在下一代无线系统中，有意放宽奈奎斯特正交性条件，一方面可以在相同带宽下实现更高的传输速率（即提高SE）和/或降低信噪比以保持通信质量（即提高EE）。另一方面，它会导致时域上相邻符号之间的码间干扰（ISI）和频域上相邻子载波之间的载波间干扰（ICI）。这种创新的非正交物理层传输在文献中通常被称为时频封装（TFP）或比奈奎斯特信号（FTNS）更快。研究计划的长期目标是探索新的传输和接收技术，以提高设计SE/EE无线系统的知识水平。为了实现这一目标，提出的研究计划有以下三个短期目标：1)开发创新的低复杂性预编码和检测技术，以消除TFP/FTNS的预期ISI和/或ICI。2)研究TFP/FTNS与下一代无线系统的其他候选技术（如多输入多输出（MIMO）天线和/或索引调制（IM））的集成（以充分表征其优势）。3)分析和量化各种传输损伤，如射频前端的同相和正交（IQ）不平衡、局部振荡器不稳定引起的相位噪声和功率放大器非线性对TFP/FTNS性能的影响，并开发创新的信号处理技术来补偿它们的有害影响。拟议的研究计划将开发新的信号处理技术，以实现SE/EE下一代无线系统的开发。该研究计划的研究结果有望引起无线/电信行业的注意，从而促进未来的研究合作。在该研究项目中培养的高素质人才将获得无线通信和数字信号处理方面的先进技能，在未来的职业生涯中脱颖而出，并为加拿大的经济增长做出贡献。

Next-generation wireless systems will have novel use cases that require gigabit experience of end-users to support data-hungry wireless applications (such as 4K streaming) and stringent energy consumption to support the expected massive connectivity. Such requirements pose several technical challenges for the existing wireless systems infrastructure and there is a need to explore novel techniques to improve the spectral efficiency (SE) and energy efficiency (EE) of next-generation wireless systems. Conventional communication systems follow the Nyquist theorem and use orthogonal pulses for transmission in time and/or frequency domains. This simplifies the transmitter and receiver designs; however, it also limits the performance. Intentionally relaxing the Nyquist orthogonality condition in next-generation wireless systems, on one hand, will allow higher transmission rates in the same bandwidth (i.e., improve the SE) and/or will result in lower signal-to-noise ratio to maintain the communication quality (i.e., improve the EE). On the other hand, it will result in intersymbol interference (ISI) between adjacent symbols in the time domain and/or intercarrier interference (ICI) between adjacent subcarriers in the frequency domain. Such innovative non-orthogonal physical layer transmission is commonly referred to in the literature as time-frequency packing (TFP) or faster-than-Nyquist signaling (FTNS). The long-term objective of the research program is to explore novel transmission and reception techniques to advance the state-of-knowledge on designing SE/EE wireless systems. To achieve this target, the proposed research program has the following three short term objectives: 1) developing innovative low-complexity precoding and detection techniques to remove the expected ISI and/or ICI of TFP/FTNS. 2) investigating the integration of TFP/FTNS (to fully characterize its benefits) with other candidate technologies for next-generation wireless systems such as multiple-input-multiple-output (MIMO) antennas and/or index modulation (IM). 3) analyzing and quantifying various transmission impairments, such as, in-phase and quadrature (IQ) imbalance of radio frequency (RF) front-end, phase-noise due to local oscillators instabilities, and power amplifier nonlinearities, on the performance of TFP/FTNS and developing innovative signal processing techniques to compensate for their harmful effects. The proposed research program will develop novel signal processing techniques to enable the development of SE/EE next-generation wireless systems. The findings of the research program are expected to attract the attention of the wireless/telecommunication industry, and hence, facilitate future research collaboration. The highly qualified personnel trained in this research program will acquire advanced skills in wireless communications and digital signal processing to excel in their future careers and contribute to Canada's economic growth.