# Extending the Coverage of IEEE 802.15.4z HRP UWB Ranging
## 4 Experimental Results and Discussion
### Experiments on Link Performances at a Fixed Distance  
Figure 10 shows the hardware used in the experiment and the communication link's experimental environment at a fixed distance of 10 m. The Qorvo DW3000 HRP UWB IC was controlled by an NRF52840-DK microcontroller board, and the PHY parameters, such as the PSRs, PACs, and data rate, could be flexibly set through the embedded programming of the microcontroller. The output of the transmitter was adjusted in 1 dB units to reproduce various link conditions. In the first experiment, the SHR reception rate (HRR) and the packet reception rate (PRR), including the SHR and DP, were measured while changing the parameters and transmitter output at a fixed distance of 10 m to verify the link budget difference between the preamble and DP. Through this, the difference in the reception of the  
Figure 9: Summary of ranging coverage extension concepts for IEEE 802.15.4z HRP UWB.  
preamble and DP of the packet was quantitatively compared. The experiment used the SP0 packet format of IEEE 802.15.4z, and the RF parameters were set as specified in Table 4. In this experiment, the PSR count was fixed to 128, and the PAC count was fixed to 8. Oorvo's DW3000 UWB IC provides a function to adjust the transmit power to compensate for the difference between the RF output of the chip and the actual RF output and antenna loss [23]. For example, it supports a maximum output of \(-41.3\) dBm/MHz while complying with the spectrum emission regulations and is adjustable from 0 dB up to \(-30\) dB. In this experiment, packets were transmitted while adjusting the TX power gain of the transmitter in 1 dB units. In order to analyze the reception status of the HRP UWB IC and the success or failure of packet reception, register values such as Receiver PHY Header Detect (RXPHD) and Receiver PHY Header Error (RXPHE) of the system status register (SYS_STATUS) were monitored, and 200 packets were transmitted for each experimental condition. Through this experiment, we could find out whether the packet was received and the error rate of the DP and compare and analyze the PER performance between the preamble and the DP.  
Figure 11 shows the packet reception characteristics as a function of the transmission power through the coarse and fine gain adjustments in the DW3000 IC. The experimental results show that a reception success rate of about 80% or higher was achieved from \(-17\) dB at 850 kbps, while the same reception success rate was achieved from about \(-11\) dB at 6.8 Mbps. This means that the low-speed (850 kbps) data transmission provided about 6 dB of link gain compared with the high-speed (6.8 Mbps) data transmission. The reason why a gain of 6 dB was observed, which was slightly smaller than the theoretically suggested 9 dB, was probably due to the interaction between the synchronization performance in the SYNC (preamble) and the reception performance in the DP, which was not considered in the link analysis; that is, in the case of 6.8 Mbps, stable reception was possible in the SYNC, but due to an insufficient link margin in the DP, there was an overall link performance difference of about \(-6\) dB, whereas in the case of 850 kbps, the reception performances of the SYNC and DP sections were similarly close, showing that the insufficient link margin of the SYNC also affected the DP performance. Through this, the link budget difference between the preamble and DP was clearly revealed in the experiment, and the link difference according to the change in data transmission speed could be quantitatively confirmed.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**PHY Setting** & **Values** \\ \hline RF channel & CH5 \\ PRF & 64 MHz \\ PSR & 32, 64, **128**, 256, 512, 1024, 2048, 4096 \\ PAC & 4, 8, 16, 32 \\ DP & 850 kbps, 6.8 Mbps \\ \hline \hline \end{tabular}
\end{table}
Table 4: Configuration PHY settings in DW 3000 UWB module.  
Figure 10: Link experiment set-up at 10 m using DW3000 UWB module.