The transmission distance of satellite IoT is much further than terrestrial IoT, resulting in a significant power loss on the transmission link. Thus the received signal power at a receiver will be significantly lower. As a low-power and long-range modulation method, LoRa has received much attention. Combining a high-performance FEC coding and LoRa modulation with a significant spreading factor enables reliable communication at very low signal-to-noise ratios. However, LoRa modulation dramatically decrease spectral efficiency as the spreading factor increases. In this paper, we propose an interleaved LoRa transmission scheme that can achieve high spectral efficiency with a low bit error rate (BER). This paper firstly presents a non-coherent soft demodulation algorithm for LoRa and the corresponding performance comparison with the use of Turbo and LDPC codes. Then we propose a soft demodulation algorithm for interleaved-LoRa transmission. Simulation results show that Turbo coded interleaved-LoRa system outperforms the uncoded system by about 4dB at a BER=10-5, which is equivalently to a 55%~57% improvement on communication distance in free space. Furthermore,

the spectral efficiency is improved by approximately 23% compared to the existing Turbo-LoRa schemes.

Satellite IoT, Turbo code, LoRa, ICS-LoRa, SSK-ICS-LoRa