面向卫星物联网的交织 LoRa 传输方案

摘要/Abstract

摘要：

卫星物联网的传输距离要比地面物联网远得多，导致传输链路上存在较大的功率损耗，接收端的接收功率变得非常低。LoRa 技术作为一种低功耗、远距离的调制方式受到了广泛关注。将性能优异的编码方案与大扩频因子的 LoRa 调制相结合，可以实现在极低信噪比下的可靠通信。然而，LoRa 调制方案随着扩频因子的增大，频谱效率急剧降低。鉴于此，本文设计了一种交织 LoRa 传输方案，在降低误比特率

的同时确保较高的频谱效率。我们首先给出了 LoRa 的非相干软解调算法，并对 Turbo 和 LDPC 编码的 LoRa系统进行了性能仿真。接着我们提出了交织 LoRa 传输方案的软解调算法。仿真表明，在误比特率为 10-5时，本文提出的 Turbo 编码交织 LoRa 传输方案相较于未编码方案性能提高了约 4dB，等价于在自由空间下的通信距离增加了 55%~57%。与现有的 Turbo-LoRa 方案相比，频谱效率提高了约 23%。

关键词:

卫星物联网, Turbo 码, LoRa, ICS-LoRa, SSK-ICS-LoRa

Abstract:

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.

Key words:

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

罗进夏家宝白杨白宝明.

面向卫星物联网的交织 LoRa 传输方案

[J]. 天地一体化信息网络.

Luo Jin, Xia Jiabao, Bai Yang, and Bai Baoming.

Interleaved-LoRa Transmission Schemes for Satellite IoT

[J]. Space-Integrated-Ground Information Networks.

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