| 摘要: |
| 针对L波段数字航空通信系统（L-band Digital Aeronautical Communication System，LDACS）中正交频分复用（Orthogonal Frequency Division Multiplexing，OFDM）调制在高多普勒频移环境中性能下降的问题，提出了一种基于正交时频空（Orthogonal Time Frequency Space，OTFS）调制的波形设计方案。由于L波段频谱资源有限，并且未经优化的OTFS调制频谱结构不满足LDACS的性能要求，首先构建了航空信道的时延-多普勒域抽头延迟线模型，再通过对子载波设计与时域加窗等技术对OTFS调制进行波形优化，实现了可在频带受限环境下高效传输的OTFS-LDACS调制信号。仿真结果表明，优化后的OTFS调制波形不仅满足LDACS频谱约束，并且经过加窗的OTFS调制方案与加窗的OFDM调制相比带外泄露减少了5 dB，与未加窗的OTFS调制方案相比带外泄露改善了25 dB。此外，在静态多径信道和航空信道下，所提出的波形设计方案比OFDM-LDACS波形表现出更高的传输可靠性。 |
| 关键词: L波段数字航空通信系统（LDACS） 航空信道 正交时频空（OTFS）调制 波形设计 |
| DOI：10.20079/j.issn.1001-893x.250505001 |
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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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| Application of OTFS Modulation and Waveform Optimization in LDACS |
| WANG Lei,YU Junyi,MA Zengqing |
| (Tianjin Key Laboratory for Advanced Signal Processing，Civil Aviation University of China，Tianjin 300300，China) |
| Abstract: |
| For the performance degradation of orthogonal frequency division multiplexing(OFDM) modulation in L-band digital aviation communication systems(LDACS) under high Doppler frequency shifts，a waveform design based on orthogonal time frequency space(OTFS) modulation is proposed.Initially，due to limited L-band spectrum resources and the fact that the unoptimized OTFS modulation spectrum structure fails to meet LDACS performance requirements，a delay-Doppler-domain tapped-delay-line model for the aeronautical channel is constructed.Based on this model，waveform optimization for OTFS modulation is carried out through subcarrier design and time-domain windowing techniques，yielding an OTFS-LDACS waveform capable of efficient transmission under bandwidth-constrained conditions.Simulation results demonstrate that the optimized OTFS waveform not only complies with the LDACS spectral constraints but also the windowed OTFS scheme reduces out-of-band leakage by 5 dB compared with the windowed OFDM scheme，and by 25 dB compared with the non-windowed OTFS scheme.Furthermore，under both static multipath and aeronautical channel conditions，the proposed waveform provides superior reliability over OFDM-LDACS waveforms. |
| Key words: L-band digital aeronautical communication system(LDACS) aviation channel orthogonal time frequency space(OTFS) modulation waveform design |
《电讯技术》编辑部 