Aanvulling, uit https://www.scss.tcd.ie/Doug.Leith/pubs/bluetooth_rssi_study.pdf, een onderzoek van Douglas J. Leith en Stephen Farrell, School of Computer Science & Statistics, Trinity College Dublin, Ireland, van 6th May 2020 (vette opmaak toegevoegd door mij): VI. SUMMARY ANDCONCLUSIONS We report on measurements of the Bluetooth LE received signal strength taken on mobile handsets in a variety of common, real-world settings. In summary, we find that the Bluetooth LE received signal strength can vary substantially depending on the relative orientation of handsets, on absorption by the human body, reflection/absorption of radio signals in buildings and trains. Indeed we observe that the received signal strength need not decrease with increasing distance. This suggests that the development of accurate methods for proximity detection based on Bluetooth LE received signal strength is likely to be challenging and time consuming. Our measurements also suggest that it may be necessary for Bluetooth LE contact ...