LoRa扩频信道干扰与扩展性分析

doi:10.3969/j.issn.0255-8297.2024.02.003

摘要/Abstract

摘要： 为了提高LoRa通信系统节点的接入量，对LoRa通信系统的干扰及扩展性进行了详细分析。首先分析了LoRa相同扩频信道间和不同扩频信道间的干扰，得出相同扩频信道干扰严重的原因，以及不同扩频信道存在一定的干扰的情况，进而发现扩频信道间的码片间距越近干扰越严重；其次提出了一种LoRa不同扩频信道间的干扰消除算法，通过仿真验证了该算法能有效消除低扩频信道干扰的可行性；最后从理论上对LoRa原有调制解调算法进行了扩展性分析，结合LoRa技术的特点及干扰仿真结果得到LoRa技术新增扩频信道与相邻扩频信道的码片数之差大于等于128，并仿真验证了4条典型新增扩频信道的抗噪声性能、可行性，系统节点的可接入量能增加36.94%。

关键词: LoRa, 扩频信道, 干扰, 码片数, 扩展性

Abstract: In order to improve the access capacity of LoRa communication system nodes, the interference and scalability of LoRa communication system are analyzed in detail. Firstly, this paper analyzes the interference between the same spread spectrum channel and the interference between different spread spectrum channels in LoRa, and obtains the reasons for the serious interference of the same spread spectrum channel and the certain interference of different spread spectrum channels. It is found that the closer the chip spacing between spread spectrum channels, the more serious the interference is. Secondly, an interference cancellation algorithm between different LoRa spread spectrum channels is proposed. Simulation results show that the algorithm can effectively eliminate the interference of low spread spectrum channels and is feasible. Finally, the expansibility of LoRa's original modulation and demodulation algorithm is analyzed through theory. Combined with the characteristics of LoRa technology and interference simulation results, it is concluded that the difference between the number of chips of LoRa's new spread spectrum channel and adjacent spread spectrum channel is greater than or equal to 128. The antinoise performance and feasibility of four typical new spread spectrum channels are verified by simulation, and the accessible capacity of system nodes can be increased by 36.94%.

Key words: LoRa, spread spectrum channel, interference, number of chips, expansibility

中图分类号:

TN925.5

雷芳, 陈博, 吕京昭. LoRa扩频信道干扰与扩展性分析[J]. 应用科学学报, 2024, 42(2): 211-221.

LEI Fang, CHEN Bo, LYU Jingzhao. Interference and Scalability Analysis of LoRa Spread Spectrum Channel[J]. Journal of Applied Sciences, 2024, 42(2): 211-221.

参考文献

[1] Nair K K, Abu-Mahfouz A M, Lefophane S. Analysis of the narrow band internet of things (NB-IoT) technology [C]//2019 Conference on Information Communications Technology and Society (ICTAS), 2019:1-6.
[2] Li Y Z, Yan X Q, Zeng L Y, et al. Research on water meter reading system based on LoRa communication [C]//2017 IEEE International Conference on Smart Grid and Smart Cities (ICSGSC), 2017:248-251.
[3] Chen T H, Eager D, Makaroff D. Efficient image transmission using LoRa technology in agricultural monitoring IoT systems [C]//2019 International Conference on Internet of Things and IEEE Green Computing and Communications and IEEE Cyber, Physical and Social Computing and IEEE Smart Data, 2019:937-944.
[4] 何诚刚. 基于LoRa的无线监测系统设计[J]. 山东农业大学学报(自然科学版), 2018, 49(3):528-530. He C G. Design for a wireless monitoring system based on LoRa [J]. Journal of Shandong Agricultural University (Natural Science Edition), 2018, 49(3):528-530. (in Chinese)
[5] Augustin A, Yi J Z, Clausen T, et al. A study of LoRa:long range & low power networks for the internet of things [J]. Sensors, 2016, 16(9):1466.
[6] Ghanaatian R, Afisiadis O, Cotting M, et al. LoRa digital receiver analysis and implementation [C]//2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2019:1498-1502.
[7] Lim J T, Han Y. Spreading factor allocation for massive connectivity in LoRa systems [J]. IEEE Communications Letters, 2018, 22(4):800-803.
[8] Adelantado F, Vilajosana X, Tuset-Peiro P, et al. Understanding the limits of LoRaWAN [J]. IEEE Communications Magazine, 2017, 55(9):34-40.
[9] Croce D, Gucciardo M, Mangione S, et al. Impact of LoRa imperfect orthogonality:analysis of link-level performance [J]. IEEE Communications Letters, 2018, 22(4):796-799.
[10] Beltramelli L, Mahmood A, Österberg P, et al. LoRa beyond ALOHA:an investigation of alternative random access protocols [J]. IEEE Transactions on Industrial Informatics, 2021, 17(5):3544-3554.
[11] Cuomo F, Campo M, Caponi A, et al. EXPLoRa:extending the performance of LoRa by suitable spreading factor allocations [C]//2017 IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2017:1-8.
[12] Mikhaylov K, Petaejaejaervi J, Haenninen T. Analysis of capacity and scalability of the LoRa low power wide area network technology [C]//European Wireless 2016; 22th European Wireless Conference, 2016:1-6.
[13] El Rachkidy N, Guitton A, Kaneko M. Decoding superposed LoRa signals [C]//2018 IEEE 43rd Conference on Local Computer Networks (LCN), 2018:184-190.
[14] Laporte-Fauret B, Ben Temim M A, Ferre G, et al. An enhanced LoRa-like receiver for the simultaneous reception of two interfering signals [C]//2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), 2019:1-6.
[15] Ben Temim M A, Ferré G, Laporte-Fauret B, et al. An enhanced receiver to decode superposed LoRa-like signals [C]//IEEE Internet of Things Journal, 2020:7419-7431.
[16] 刘树聃, 孙继炫. LoRa调制技术及解调算法[J]. 电讯技术, 2018, 58(12):1447-1451. Liu S D, Sun J X. LoRa modulation and demodulation algorithm [J]. Telecommunication Engineering, 2018, 58(12):1447-1451. (in Chinese)