In this letter, we consider the problem of increasing the spectral efficiency of a chirp-based communication system. Existing radar systems employ non-overlapping chirps with a large time-bandwidth product, and a modulation of these chirps for communications systems results in low spectral efficiency. Chirp overlapping can enhance the data rate, but it suffers from performance degradation due to intersymbol interference (ISI). In this letter, we derive a useful bit error rate (BER) expression to analyze the performance of a system with a finite number of overlapped chirps. Additionally, we investigate the conditions in which the ISI can be reduced while approaching the Nyquist signaling rate. We then propose simple linear equalization techniques to compensate for the ISI, allowing us to achieve faster-than-Nyquist signaling. We demonstrate the effectiveness of our approach by extensive analytical and numerical results.

中文翻译：

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重叠线性调频系统的高效通信

在这封信中，我们考虑了提高基于啁啾通信系统的频谱效率的问题。现有雷达系统采用具有大时间带宽积的非重叠啁啾，并且对通信系统的这些啁啾调制导致低频谱效率。线性调频重叠可以提高数据速率，但会因码间干扰 (ISI) 而导致性能下降。在这封信中，我们导出了一个有用的误码率 (BER) 表达式来分析具有有限数量重叠啁啾的系统的性能。此外，我们研究了在接近奈奎斯特信号速率时可以降低 ISI 的条件。然后我们提出了简单的线性均衡技术来补偿 ISI，使我们能够实现比奈奎斯特更快的信令。