| 摘要: |
| 正交时频空（Orthogonal Time Frequency Space，OTFS）信号调制过程中存在一定的带外（Out-of-Band，OOB）泄露，会导致相邻信道干扰，影响通信系统性能。针对这一问题，分析了OTFS系统功率谱特性，提出了一种新带外功率抑制方法。首先，理论推导出OTFS信号的精确功率谱密度（Power Spectral Density，PSD）数学表达式，明确影响OTFS带外功率的因素；其次，为抑制带外功率，提出了一种基于多项式抵消编码的正交时频空（Polynomial Cancellation Coding Orthogonal Time Frequency Space，PCC-OTFS）调制方案，利用PCC技术重构OTFS子载波，使相邻子载波以相互抵消的系数组成子载波对，加快子载波频谱旁瓣滚降，并给出矩形脉冲与升余弦脉冲PCC-OTFS的功率谱密度计算方法，探讨了其功率谱滚降特性。实验结果表明，相比矩形脉冲和圆形长脉冲形状（Circular-Prolate Pulse Shape，CPPS），升余弦脉冲PCC-OTFS可降低带外功率约117 dB和40 dB。 |
| 关键词: 正交时频空(OTFS) 带外泄露抑制 多项式抵消编码(PCC) |
| DOI：10.20079/j.issn.1001-893x.241016002 |
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| 基金项目:国家自然科学基金资助项目（U2233216） |
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| An Effective Out-of-band Power Suppression Method for OTFS |
| LI Dongxia,JIN Ke,QIU Xinyi,LIU Haitao |
| (College of Electronic Information and Automation，Civil Aviation University of China，Tianjin 300300，China) |
| Abstract: |
| The orthogonal time frequency space(OTFS) signal modulation process exhibits a certain degree of out-of-band(OOB) leakage，which can cause interference with adjacent channels and degrade the performance of the communication system.In response to this issue，the power spectrum characteristics of the OTFS system are analyzed，and a novel OOB power suppression method is proposed.First，the precise mathematical expression for the power spectral density(PSD) of OTFS signals is theoretically derived，explicitly identifying the factors influencing OTFS OOB power.Furthermore，to suppress OOB power，a polynomial cancellation coding OTFS(PCC-OTFS) modulation scheme is proposed.This scheme leverages PCC technology to reconstruct OTFS subcarriers，forming subcarrier pairs with mutually canceling coefficients to accelerate the spectral sidelobe roll-off of subcarriers.Additionally，the power spectral density(PSD) calculation methods for PCC-OTFS with rectangular and raised-cosine pulses are derived，and their power spectrum roll-off characteristics are analyzed.Experimental results demonstrate that the PCC-OTFS scheme significantly reduces OTFS OOB leakage，achieving approximately 117 dB and 40 dB reductions in OOB power compared with rectangular pulses and circular-prolate pulse shape(CPPS)，respectively，when using raised cosine pulses in PCC-OTFS. |
| Key words: orthogonal time frequency space(OTFS) out-of-band suppression polynomial cancellation coding(PCC) |
《电讯技术》编辑部 