面向卫星物联网的交织LoRa传输方案  

Interleaved-LoRa Transmission Scheme for Satellite IoT

作　　者：罗进 夏家宝 白杨 白宝明[1,2] LUO Jin;XIA Jiabao;BAI Yang;BAI Baoming(State Key Laboratory of ISN,Xidian University,Xi'an 710071,China;Guangzhou Institute of Technology,Xidian University,Guangzhou 510555,China)

机构地区：[1]西安电子科技大学空天地一体化综合业务网全国重点实验室,陕西西安710071 [2]西安电子科技大学广州研究院,广东广州510555

出　　处：《天地一体化信息网络》2023年第1期89-97,共9页Space-Integrated-Ground Information Networks

基　　金：国家自然科学基金资助项目(No.62171356);国家重点研发计划资助项目(No.2021YFB2900501)。

摘　　要：卫星物联网的传输距离要比地面物联网远得多,导致其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。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,设计一种交织LoRa传输方案,在降低误比特率的同时确保较高的频谱效率。首先给出LoRa的非相干软解调算法,并对Turbo和LDPC编码的LoRa系统进行性能仿真。接着提出交织LoRa传输方案的软解调算法。仿真结果表明,在误比特率为10-5时,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4 dB,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%。The transmission distance of satellite IoT is much further than terrestrial IoT,resulting in a signifi cant power loss on the transmission link.Thus the received signal power at a receiver will be signifi cantly lower.Combining a high-performance FEC coding and LoRa modulation with a signifi cant spreading factor enables reliable communication at very low signal-to-noise ratios.However,LoRa modulation dramatically decrease spectral effi ciency as the spreading factor increases.An interleaved LoRa transmission scheme that could achieved high spectral effi ciency with a low bit error rate(BER)was proposed.Firstly,a non-coherent soft demodulation algorithm was presented for LoRa and the corresponding performance comparison with the use of Turbo and LDPC codes.Then proposed a soft demodulation algorithm for interleaved-LoRa transmission.Simulation results showed that Turbo coded interleaved-LoRa system outperformed the uncoded system by about 4 dB at a BER=10-5,which was equivalently to a 55%~57%improvement on communication distance in free space.Furthermore,the spectral effi ciency was improved by approximately 23%compared to the existing Turbo-LoRa scheme.

关 键 词：卫星物联网 TURBO码 LoRa ICS-LoRa SSK-ICS-LoRa 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]