# Extending the Coverage of IEEE 802.15.4z HRP UWB Ranging
## 4 Experimental Results and Discussion
### Maximum Ranging Experiment in Indoor Environments  
To evaluate the practical ranging performance of the proposed physical layer parameter adjustments under real-world indoor conditions, additional experiments were conducted in the hallway of the engineering building of Kookmin University in Seoul, Korea. The measurement environment consisted of a straight hallway (line-of-sight (LOS) dominant, with significant multipath effects) with a length of approximately 90 m. Multipath propagation in the straight hallway caused increased signal spreading, slightly affecting the maximum achievable ranging distance. However, in the NLOS corner area, preamble detection failures occurred much more frequently, leading to a substantial reduction in the maximum measurable distance.  
Three different physical layer parameter configurations were tested to comprehensively assess the ranging performance. For each case, experiments were conducted at both the 850 kbps and 6.8 Mbps data rates to investigate the impact of the transmission speed on ranging performance. The details of the tested parameter settings are summarized in Table 5.  
Figure 14 presents the maximum ranging distances achieved under each experimental condition overlaid on the building's floor plan. Different marker shapes and colors represent the physical layer settings; red circles indicate the short case, green squares represent the baseline (middle) case, and blue stars correspond to the long case. Solid markers denote the results at 850 kbps, while hollow markers represent the results at 6.8 Mbps. This visualization highlights the influence of the physical layer parameters and data rate on the achievable ranging distances in real-world indoor environments.  
The experimental results are summarized in Table 6, which shows the maximum achievable distances under each configuration based on a packet reception success rate of 90%. At a data rate of 6.8 Mbps, both the long and middle cases exhibited a rapid decrease in ranging performance, with distance measurement failures occurring near 65 m. In contrast, the short case showed an earlier failure at approximately 62.3 m, which was slightly shorter than its 850 kbps maximum distance (68.8 m), likely due to the link budget limitations of the DP. When operating at 850 kbps, the ranging performance improved significantly, as the link budget of the DP was no longer the dominant limiting factor. Instead, the PSR became the main contributor to the ranging capability. As a result, the maximum achievable distances followed the order of short, middle, and long cases, directly  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Case** & **PSR** & **PAC** & **DP** \\ \hline Short & 64 & 4 & 850 kbps, 6.8 Mbps \\ Middle & 256 & 4 & 850 kbps, 6.8 Mbps \\ Long & 4096 & 32 & 850 kbps, 6.8 Mbps \\ \hline \hline \end{tabular}
\end{table}
Table 5: Experimental parameter configurations for ranging performance evaluation.  
reflecting the impact of the PSR length on preamble detection performance under multipath conditions. In particular, the long case successfully achieved distance measurements up to the end of the hallway (90 m) with high reliability, and the results suggest that even longer distances would be possible if the physical space allowed them. These observations confirm that the selection of both the DP parameters and the PSR critically impacted the maximum achievable ranging performance. Furthermore, it was demonstrated that reliable extended UWB ranging is achievable even in real-world indoor environments with significant multipath effects, such as a university campus hallway.