# Experimental Evaluation of the Packet Reception Performance of LoRa
## 7 Conclusions  
It is believed that a better understanding of the relationship between physical layer parameters and the packet reception performance of LoRa can help deal with technical challenges, such as reliability, delay, and energy consumption. Therefore, we conducted extensive experimental evaluations on the influence of physical layer parameters on the  
Figure 13: Transmission time t for different parameter configurations. The lower the (t), the better. (a) shows result of the average time required for each packet to be successfully transmitted; (b) shows the result of the transmission time when the packet length is 32 bytes with different SNRs.  
packet reception performance of LoRa. The experimental results found the following: (i) If the SF value is increased by one, the SNR of the high PER region (PER \(\approx\) 1) will decrease by 2 or 3 dB; (ii) every time the BW value doubles, the range of the reliable communication area (PER \(\approx\) 0% interference immunity area) will decrease by one SF index and the SNR will also be reduced by 3 dB; and (iii) compared with the impact of SF, although CR has a smaller impact, it is still important in reducing PER. We also propose a PER expression for different packet lengths to analyze the impact of the packet length on the packet reception performance of LoRa. The extensive experimental results confirm the validity of the theory and illustrate that the packet length only has a significant effect on the packet reception performance of LoRa at the edge of the communication link. Meanwhile, the experimental results also suggest that if a node needs to send a large amount of data, the node should use a long packet transmission scheme. Compared with long packets, short packets mean more headers are sent, which will consume more transmission time and energy. Finally, we have discussed how to combine parameters based on the experimental results, and reduce energy consumption by shortening the time for successful communication, thereby balancing reliability, delay, and energy consumption. The solution we propose can quickly combine parameters according to the SNR to meet the requirements of different scenarios and shorten the communication time by about 50% compared with the traditional transmission solution, which greatly reduces the energy consumption.  
[PERSON] designed and performed the entire experiment, [PERSON] participated in part of the experiment, and [PERSON] took the lead in writing the manuscript. All authors analyzed the data and provided critical feedback on the final manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Research and Application of Online-Monitoring and Intelligent Emergency Rescue Technology in Hazardous Chemicals Industrial Zone; grant number 19 DZ1202200.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to [the project is still in progress and the data needs to be kept confidential].  
The authors would like to thank [PERSON] and [PERSON] for their valuable comments and suggestions.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
IoTInternet of Things  
SFSpreading Factor  
BWBandwidth  
CRCoding Rate  
SFDStart Frame Delimiter  
PERPacket Error Ratio  
SNRSignal to Noise Ratio  
CSSChirp Spread Spectrum  
LPWANLow Power Wide Area Network  
IFFTInverse Fast Fourier Transform  
FFTFast Fourier Transform  
RsSymbol Rate  
DRData Rate  
CRCCyclic Redundancy Check  
FECForward Error Correction