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arXiv 2303.06009eess.SP
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恒包络OFDM波形模糊函数的特征

Characterizing the Ambiguity Function of Constant-Envelope OFDM Waveforms

David G. Felton, David A. Hague

摘要:

研究了采用相移键控(PSK)的恒包络正交频分复用(CE-OFDM)波形的雷达模糊函数(AF)特性。CE-OFDM实际上是多音正弦调频(MTSFM)波形的特殊情况,其允许将MTSFM模型的许多相同数学技术应用于CE-OFDM模型。这导致CE-OFDM波形的频谱、AF和自相关函数(ACF)的新颖紧凑的封闭形式表达式。CE-OFDM的AF的主瓣结构由模糊椭圆(EOA)模型表征。这产生CE-OFDM的均方根(RMS)带宽和波形的AF主瓣中存在的距离-多普勒耦合程度的精确闭合形式表达式。这些表达式示出了采用PSK作为符号编码方案的CE-OFDM波形对于固定的调制指数$h$和子载波数目$L$将具有固定的RMS带宽。此外,我们表明EOA模型预测,采用PSK编码的CE-OFDM波形几乎总是具有“图钉状”AF形状。

英文摘要:

This paper investigates the radar Ambiguity Function (AF) properties of Constant Envelope Orthogonal Frequency Division Multiplexing (CE-OFDM) waveforms employing Phase-Shift Keying (PSK). The CE-OFDM is in fact a special case of the Multi-Tone Sinusoidal Frequency Modulated (MTSFM) waveform which allows for applying many of the same mathematical techniques of the MTSFM model to the CE-OFDM model. This results in novel compact closed-form expressions for the spectrum, AF, and Auto-Correlation Function (ACF) of the CE-OFDM waveform. The mainlobe structure of the CE-OFDM's AF is characterized by the Ellipse of Ambigiuity (EOA) model. This produces precise closed-form expressions for the CE-OFDM's Root-Mean Square (RMS) bandwidth and the degree of range-Doppler coupling present in the waveform's AF mainlobe. These expressions show that a CE-OFDM waveform employing PSK as the symbol encoding scheme will possess a fixed RMS bandwidth for fixed modulation index $h$ and number of sub-carriers $L$. Additionally, we show that the EOA model predicts that a CE-OFDM waveform employing PSK encoding will almost always possess a ``Thumbtack-Like'' AF shape.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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