*5.2. Range Extension*

In this case, our proposed range extension method is applied using digital delay offset in the received signal to realize larger range values such as 10 m. In Figure 9, ranging performance using the conventional (Figure 9a–c) and the proposed method (Figure 9d–f) is shown, when the target location is within the CPI, within the OFDM symbol duration, and beyond the OFDM symbol duration.

**Figure 9.** Range extension of the measurement results, where the range is extended through offset– delay. (**a**–**c**) Results of conventional approach for targets at 0.6 m, 10 m, and 17.65 m, respectively. (**d**–**f**) Results obtained through the proposed range extension method for the arrangements as for results in (**a**–**c**).

Figure 9a is the range plot for the target placed at 0.6 m in the measurement, whereas Figure 9b shows the same target shifted to 10 m, which reduces processing gain and, in turn, performance degradation. Similarly, the target in Figure 9c is beyond the OFDM symbol duration and does not appear in the conventional OFDM-based processing. As a benefit, the results obtained through our proposed method are shown in Figure 9d–f, and all targets are identifiable for all the same cases. Multiple reflections from the target and reflection from the wall appear as mentioned in Figure 8a.


**Table 3.** Number of targets and their arrangements for different scenarios.
