# BLE Signal Reception and Localization Performance with Varying Receiver and Beacon Setups
## 3 BLE Signal Analysis
### Ceiling Gateways BLE Signal Segments  
A similar trend is observed for the ceiling GW. Longer received signal segments correspond to higher mean signal values across all BLE positions. This is accompanied by a reduction in standard deviation, indicating increased signal stability. Specific patterns are also noted across body positions, with the shoulder and front pocket positions consistently showing higher mean signal values, particularly in longer signal segments. Figure 8 illustrates the RSSI segments, of range 60% to 70% threshold, emitted by the shoulder beacon and received from the ceiling gateways. Figure 8: Example of signal segments (dBm) by the shoulder beacon received from the ceiling-mounted gateways, illustrating the range between the 60% and 70% thresholds. Figure 7: Received signal strength characteristics received from the wall GWs. Table 2 presents data on the quantity of BLE signal segments and their standard deviation across different length ranges for shoulder positions. Figure 9 shows the distribution of BLE signal segments received from the wall-mounted GW, and their quality across different body positions. The analysis of BLE signal segments received at ceiling-mounted gateways reveals variations in the distribution of short and long segments across different body positions. In the front pocket and back pocket positions, the short segment length range is characterized by a higher number of shorter segments, which may indicate challenges in immediate signal stability. In contrast, the long segment length range exhibits fewer occurrences, suggesting more stable and prolonged connections. The top pocket position shows a balanced distribution of short and long segments, reflecting a combination of immediate and sustained signal stability. The shoulder position, in turn, demonstrates fewer short segments, indicating a relatively higher signal reception effectiveness. The wrist position, with no short segments observed, exhibits a significant proportion of long segments, implying a preference for more sustained, robust connections. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Position** & **Segments Length Range** & **Segment Quantity** & **Avg Quality STD** \\ \hline \multirow{8}{*}{Shoulder} & 0–10\% & 7 & 1.9628 \\ \cline{2-4}  & 10–20\% & 10 & 2.3331 \\ \cline{2-4}  & 20–30\% & 23 & 2.8832 \\ \cline{2-4}  & 30–40\% & 27 & 2.7737 \\ \cline{2-4}  & 40–50\% & 38 & 2.899 \\ \cline{2-4}  & 50–60\% & 43 & 2.7357 \\ \cline{2-4}  & 60–70\% & 37 & 2.8163 \\ \cline{2-4}  & 70–80\% & 24 & 2.6284 \\ \cline{2-4}  & 80–90\% & 23 & 3.0026 \\ \cline{2-4}  & 90–100\% & 38 & 2.6299 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Quantity of BLE signal segments and RSSI standard deviation across different segment length ranges from ceiling-mounted gateways. Figure 9: Distribution of BLE signal segments received from the ceiling GWs and their quality across different body positions. The left subfigure shows the quantity of signal segments within various length ranges, while the right subfigure illustrates the standard deviation of signal quality within each group of signal segments. The standard deviation of signal values across all segment lengths and BLE positions remains relatively consistent. The characteristics of ceiling BLE signal performance are further illustrated in the violin plot shown in Figure 10. The analysis of signals from ceiling-mounted GWs across various BLE positions reveals distinct patterns in signal strength. The minimum signal values show that the shoulder position exhibits the highest at \(-80.28\) dBm, indicating relatively stronger signals compared to other body positions, while the back pocket has the lowest minimum signal strength at \(-79.47\) dBm. For maximum signal values, the back pocket records the lowest at \(-60.38\) dBm, while the shoulder position has the highest at \(-48.86\) dBm. In terms of average signal strength, the shoulder position maintains the highest value at \(-70.62\) dBm, whereas the top pocket has the lowest at \(-71.83\) dBm.