LoRa信号干扰分析与性能研究

doi:10.11772/j.issn.1001-9081.2023091233

《计算机应用》唯一官方网站 ›› 2024, Vol. 44 ›› Issue (9): 2848-2854.DOI: 10.11772/j.issn.1001-9081.2023091233

LoRa信号干扰分析与性能研究

花敏(), 魏佳楠, 赵伟, 孟硕

南京林业大学信息科学技术学院、人工智能学院，南京 210037

收稿日期:2023-09-08 修回日期:2023-11-24 接受日期:2023-12-01 发布日期:2023-12-22 出版日期:2024-09-10
通讯作者: 花敏
作者简介:魏佳楠（1999—），女，江苏宿迁人，硕士研究生，主要研究方向：功率域非正交多址接入、低功率广域网；
赵伟（1998—），男，江苏苏州人，硕士研究生，主要研究方向：低功率广域网；
孟硕（1998—），男，江苏徐州人，硕士研究生，主要研究方向：非正交多址接入、低功率广域网。
基金资助:
国家自然科学基金资助项目(61801225)

Interference analysis and performance research of LoRa signals

Min HUA(), Jia’nan WEI, Wei ZHAO, Shuo MENG

College of Information Science and Technology & College of Artificial Intelligence，Nanjing Forestry University，Nanjing Jiangsu 210037，China

Received:2023-09-08 Revised:2023-11-24 Accepted:2023-12-01 Online:2023-12-22 Published:2024-09-10
Contact: Min HUA
About author:WEI Jia’nan， born in 1999， M. S. candidate. Her research interests include power domain non-orthogonal multiple access technology， low-power wide area network.
ZHAO Wei， born in 1998， M. S. candidate. His research interests include low-power wide area network.
MENG Shuo， born in 1998， M. S. candidate. His research interests include non-orthogonal multiple access technology， low-power wide area network.
Supported by:
This work is partially supported by National Natural Science Foundation of China(61801225)

摘要/Abstract

摘要：

LoRa（Long Range radio）系统在当前不断发展的低功率广域网（LPWAN）中处于相对领先地位。它的MAC层采用的是基于ALOHA的接入协议。该接入机制虽然简单易实现，但同时也容易加剧冲突和碰撞的发生，降低整个系统的通信性能。因此，需要研究多个终端同时占用信道资源时的相互干扰情况，而LoRa信号的扩频因子（SF）将决定信号的通信覆盖范围。因此，分析了干扰信号的SF与发送信号的SF相同以及不同时，干扰信号对发送信号解调性能的影响。实验结果表明，相同SF信号间的干扰影响相对较大，而干扰信号使用的SF与发送信号不同时，干扰的影响相对较小。通过理论分析，获得了接收端正确解调时所要求的信干比（SIR）。可见，不同SF的LoRa信号可看作伪正交。

关键词: 低功率广域网, LoRa, 扩频因子, 信号干扰分析, 通信性能

Abstract:

LoRa （Long Range radio） system is in a relatively leading position in the currently developing LPWAN （Low Power Wide Area Network）. Its MAC layer adopts an ALOHA-based access protocol. Although this access mechanism is simple and easy to implement， it also easily aggravates the occurrence of conflicts and collisions， degrading the communication performance of the whole system. Therefore， it is necessary to study the mutual interference when multiple terminals occupy the channel resources at the same time. For an LoRa signal， its SF （Spreading Factor） determines the communication coverage of the signal. Thus， the effect of an interference signal on the demodulation performance of a transmitting signal was analyzed when the SF of the interference signal was the same as or different from the SF of the transmitting signal. Experimental results show that the interference effect between the same SF signals is relatively large. When the SF of the interference signal is different from that of the transmitting signal， the effect of interference is relatively small. The SIR （Signal-to-Interference Ratio） required for correct demodulation at the receiver side was obtained through theoretical analyses. It can be seen that LoRa signals with different SFs can be viewed as pseudo-orthogonal.

Key words: Low Power Wide Area Network (LPWAN), Long Range radio (LoRa), Spreading Factor (SF), signal interference analysis, communication performance

中图分类号:

TN929.5

花敏, 魏佳楠, 赵伟, 孟硕. LoRa信号干扰分析与性能研究[J]. 计算机应用, 2024, 44(9): 2848-2854.

Min HUA, Jia’nan WEI, Wei ZHAO, Shuo MENG. Interference analysis and performance research of LoRa signals[J]. Journal of Computer Applications, 2024, 44(9): 2848-2854.

图/表 8

图1 LoRa收发端数学模型

Fig. 1 Mathematical model of LoRa transceiver

图2 SF相同时的发送信号和干扰信号模型

Fig. 2 Transmitting signal and interference signal models with same SF

图3 ηk波形

Fig. 3 Waveform of ηk

图4 SF=7时不同?所对应的符号解调错误概率

Fig. 4 Symbol demodulation error probabilities corresponding to different SIRs when SF=7

图5 发送信号和干扰信号模型（SFI>SFM）

Fig. 5 Transmitting signal and interference signal models （SFI>SFM）

图6 菲涅耳积分曲线

Fig. 6 Fresnel integral curves

图7 发送信号和干扰信号的模型（SFI<SFM）

Fig. 7 Transmitting signal and interference signal models （SFI<SFM）

表1 无噪声情况下的信干比?的平均值

Tab. 1 Average value of signal-to-interference ratio ? with absence of noise

$S F M$	不同 $S F I$ 下的 $ϕ$ /dB
$S F M$	$S F I = 7$	$S F I = 8$	$S F I = 9$	$S F I = 10$	$S F I = 11$	$S F I = 12$
7	—	-16.5	-18.4	-19.0	-19.3	-19.5
8	-19.2	—	-19.6	-21.4	-22.1	-22.4
9	-21.3	-22.1	—	-22.6	-24.4	-25.1
10	-23.3	-24.3	-25.2	—	-25.7	-27.4
11	-25.8	-26.3	-27.3	-28.2	—	-28.7
12	-28.5	-28.7	-29.3	-29.8	-31.4	—

表1 无噪声情况下的信干比?的平均值

Tab. 1 Average value of signal-to-interference ratio ? with absence of noise

$S F M$	不同 $S F I$ 下的 $ϕ$ /dB
$S F M$	$S F I = 7$	$S F I = 8$	$S F I = 9$	$S F I = 10$	$S F I = 11$	$S F I = 12$
7	—	-16.5	-18.4	-19.0	-19.3	-19.5
8	-19.2	—	-19.6	-21.4	-22.1	-22.4
9	-21.3	-22.1	—	-22.6	-24.4	-25.1
10	-23.3	-24.3	-25.2	—	-25.7	-27.4
11	-25.8	-26.3	-27.3	-28.2	—	-28.7
12	-28.5	-28.7	-29.3	-29.8	-31.4	—

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LoRa信号干扰分析与性能研究

Interference analysis and performance research of LoRa signals

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