Chirp spread spectrum toward the Nyquist signaling rate - orthogonality condition and applications

Ouyang, Xing; Dobre, Octavia A.; Guan, Yong Liang; Zhao, Jian

Chirp spread spectrum toward the Nyquist signaling rate - orthogonality condition and applications

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Files

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Accepted Version

Date

2017-08-08

Authors

Ouyang, Xing

Dobre, Octavia A.

Guan, Yong Liang

Zhao, Jian

Publisher

Institute of Electrical and Electronics Engineers

Published Version

10.1109/LSP.2017.2737596

Abstract

With the proliferation of Internet-of-Things (IoT), the chirp spread spectrum (CSS) technique is re-emerging for communications. Although CSS can offer high processing gain, its poor spectral efficiency and the lack of orthogonality among different chirps tend to limit its potential. In this paper, we derive the condition to orthogonally multiplex an arbitrary number of linear chirps. For the first time in the literature, we show that the maximum modulation rate of the linear continuous-time chirps satisfying the orthogonality condition can approach the Nyquist signaling rate, the same as single-carrier waveforms with Nyquist signaling or orthogonal frequency-division multiplexing signals. The performance of the proposed orthogonal CSS is analyzed in comparison to the emerging LoRa systems for IoT applications with power constraint, and its capability for high-speed communications is also demonstrated in the sense of Nyquist signaling.

Keywords

IoT , Chirp , Diffraction , Modulation , CSS , Fresnel transform , LoRa , Nyquist , Internet-of-Things , Orthogonal chirp-division multiplexing , OCDM , Cascading style sheets , Bandwidth

Citation

Ouyang, X., Dobre, O. A., Guan, Y. L. and Zhao, J. (2017) 'Chirp spread spectrum toward the Nyquist signaling rate - orthogonality condition and applications', IEEE Signal Processing Letters, 24(10), pp.1488-1492. doi: 10.1109/LSP.2017.2737596