Spatial Correlation of Channel State Information in Real LoRa Measurement

The Internet of Things (IoT) is developed to ensure monitoring and connectivity within different applications. Thus, it is critical to study the channel propagation characteristics in Low Power Wide Area Network (LPWAN), especially LoRaWAN. In this paper, an in-depth investigation of the reciprocity between the uplink and downlink Channel State Information (CSI) is done by performing an outdoor measurement campaign in the area of Campus Beaulieu in Rennes. At each different location, the CSI reciprocity is quantified using the Pearson Correlation Coefficient (PCC) which shows a very high linear correlation between the uplink and downlink CSI. This reciprocity feature could be utilized for the physical layer security between the node and the gateway. On the other hand, most of the CSI shapes from different locations are highly uncorrelated with each other. Hence, it can be anticipated that this could achieve significant localization gain by utilizing the frequency hopping in the LoRa systems to get access to a wider band.





References:
[1] A. A. Ghany, B. Uguen and D. Lemur, ”A Pre-processing
Algorithm Utilizing a Paired CRLB for TDoA Based IoT
Positioning,” 2020 IEEE 91st Vehicular Technology Conference
(VTC2020-Spring), Antwerp, Belgium, 2020, pp. 1-5, doi:
10.1109/VTC2020-Spring48590.2020.9128385.
[2] LoRa-Alliance - https://www.lora-alliance.org/
[3] A. A. Ghany, B. Uguen and D. Lemur, ”A Robustness Comparison of
Measured Narrowband CSI vs RSSI for IoT Localization,” 2020 IEEE
92nd Vehicular Technology Conference (VTC2020-Fall), 2020, pp. 1-5,
doi: 10.1109/VTC2020-Fall49728.2020.9348854.
[4] Augustin, A.; Yi, J.; Clausen, T.; Townsley, W.M. A Study of LoRa: Long
Range & Low Power Networks for the Internet of Things. Sensors 2016,
16, 1466.
[5] L. Li, J. Ren and Q. Zhu, ”On the application of LoRa LPWAN
technology in Sailing Monitoring System,” 2017 13th Annual Conference
on Wireless On-demand Network Systems and Services (WONS),
Jackson, WY, 2017, pp. 77-80, doi: 10.1109/WONS.2017.7888762.
[6] M. R. Seye, B. Ngom, B. Gueye and M. Diallo, ”A Study of LoRa
Coverage: Range Evaluation and Channel Attenuation Model,” 2018 1st
International Conference on Smart Cities and Communities (SCCIC),
Ouagadougou, 2018, pp. 1-4, doi: 10.1109/SCCIC.2018.8584548.
[7] R. El Chall, S. Lahoud and M. El Helou, ”LoRaWAN Network: Radio
Propagation Models and Performance Evaluation in Various Environments
in Lebanon,” in IEEE Internet of Things Journal, vol. 6, no. 2, pp.
2366-2378, April 2019, doi: 10.1109/JIOT.2019.2906838.
[8] M. Bloch, J. Barros, M. R. D. Rodrigues and S. W. McLaughlin,
”Wireless Information-Theoretic Security,” in IEEE Transactions on
Information Theory, vol. 54, no. 6, pp. 2515-2534, June 2008, doi:
10.1109/TIT.2008.921908.
[9] Ahmed Abdelghany, Bernard Uguen, Christophe Moy, Dominique Lemur.
On Superior Reliability of Effective Signal Power versus RSSI in
LoRaWAN. 28th International Conference on Telecommunications (ICT
2021), Jun 2021, London, United Kingdom. ( hal-03210318 )
[10] Tektelic KONA Macro IoT Gateway. https://www.tektelic.com/uploads/
Brochures/Kona\%20Macro.pdf
[11] Pycom documentation: https://GitHub.com/PyCom/PyCom-libraries
[12] Measurement Data. https://gitlab.com/ahmednagy/
lorawan-beaulieu-measurement-2020
[13] Benesty J., Chen J., Huang Y., Cohen I. (2009) Pearson Correlation
Coefficient. In: Noise Reduction in Speech Processing. Springer
Topics in Signal Processing, vol 2. Springer, Berlin, Heidelberg.
https://doi.org/10.1007/978-3-642-00296-0-5
[14] Gwagenn company website.http://www.gwagenn.com/en/home/