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Study of Potential Improvements of CSS Waveform for LEO based IoT System
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- Authors
- Pansoo Kim, Joon-Gyu Ryu, Seungkeun Park
- Issue Date
- 2022-09
- Citation
- Advanced Satellite Multimedia Systems Conference (ASMS) 2022 / Signal Processing for Space Communications Workshop (SPSC) 2022, pp.1-3
- Publisher
- IEEE
- Language
- English
- Type
- Conference Paper
- Abstract
- In this paper, potential techniques that can be improved are discussed based on Lora scheme which is used in terrestrial IoT waveform for the LEO satellite IoT system. For hybrid use of terrestrial and satellite network, it's identified that there are some improvements in the Lora scheme based on CSS in the following. First, the performance of the Lora transmission can be degraded in very low SNR (Signal to Noise Ratio) condition by Doppler frequency shift and drift that are generated by the motion of the LEO (Low Earth Orbit) satellite. In order to reduce the complexity of the receiver for Doppler drift estimation accuracy improvement, it is possible to consider introducing a differential CSS (Chirp Spread Spectrum) modulation scheme. Second, in order to deal with the path loss problem due to the long distance between LEO satellite and ground objects, the use of low-complexity channel coding scheme can be considered. Third, for throughput improvement, SIC (Successive Interference Cancellation) techniques can be applied to resolve collision between different user packets which are transmitted with the same SF (Spreading Factor). Finally, for better Doppler frequency estimation accuracy under the constraint of low complexity, the adaptation of preamble structure can be taken into account.
- KSP Keywords
- Channel Coding, Doppler drift, Doppler frequency estimation, Doppler frequency shift, Drift estimation, Estimation accuracy, LEO satellite, Long-distance, Low SNR, Low earth orbit(LEO), Modulation scheme