Chirp spread spectrum toward the Nyquist signaling rate - orthogonality condition and applications
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Accepted Version
Date
2017-08-08
Authors
Ouyang, Xing
Dobre, Octavia A.
Guan, Yong Liang
Zhao, Jian
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Electrical and Electronics Engineers
Published Version
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.
Description
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