reference points nochmal in optimierung erwähnt

tex_review/chapters/experiments.tex

@@ -167,8 +167,11 @@ This is more difficult using the mesh and requires the handling of baricentric c
 %As described in section \ref{sec:wifi} we used \SI{42}{} WEMOS D1 mini to provide a \docWIFI{} infrastructure throughout the building.
 Within all Wi-Fi observations, we only consider the beacons, which are identified by their well-known MAC address. 
 Other transmitters like smart TVs or smartphone hotspots are ignored as they might cause estimation errors.
-The references (fingerprints) we used to optimize the Wi-Fi models as well as the real position of the \docAPshort{}s (black dot) can be seen in fig. \ref{fig:apfingerprint} for ground level.
-Each reference location was scanned \SI{30}{} times ($\approx \SI{25}{\second}$ scan time) using a Motorola Nexus 6 at \SI{2.4}{GHz} band only.
+The references (fingerprints) we used to optimize the Wi-Fi model as well as the real position of the \docAPshort{}s (black dot) can be seen in fig. \ref{fig:apfingerprint} for ground level.
+\add{For the complete building we defined \SI{133}{} reference points for recording Wi-Fi scans. 
+An evaluation of how the number of references affects the optimization can be found in \cite{Ebner-17}.
+Increasing their number improves the result only up to a certain factor, which is why we have made a reasonable compromise between recording time and accuracy by distributing them every \SI{3}{\meter} to \SI{7}{\meter} from each other.}
+Each reference location was then scanned \SI{30}{} times ($\approx \SI{25}{\second}$ scan time) using a Motorola Nexus 6 at \SI{2.4}{GHz} band only. 
 The resulting measurements were grouped per physical transmitter and aggregated to form the average signal strength per transmitter.
 The real position of every installed beacon was measured using a laser scanner. 
 This allows a comparison with the optimized \docAPshort{} positions, what can also be seen in fig. \ref{fig:apfingerprint}.