# WISCANet: A Rapid Development Platform for Beyond 5G and 6G Radio System Prototyping
## 4 Over-the-Air Demonstrations
### 5G-Based Positioning, Navigation and Timing  
Multi-function systems are an emerging class of high-performance, highly cooperative techniques that promise many of the performance enhancements demanded by B5G and 6G applications. Implementation and validation of these complex techniques was one of the primary motivations in developing WISCANet. In the following demonstrations, we highlight how WISCANet enables us to quickly advance research in this field while traditional solutions are otherwise prohibitively expensive and difficult.  
We deployed two over-the-air implementations of a system that enables joint radar, communications, positioning, navigation, and timing (JRCPNT) [6, 8]. The system simultaneously executes 5G communications, mono- and bi-static radar, and time-of-arrival (ToA) estimation to enable precise ranging and time synchronization. We used the same laboratory deployment depicted in Figure 9 with two edge nodes using Ettus X310s.  
The first configuration operates with 10 MHz bandwidth at 915 MHz center frequency in the ISM band using standard dipole antennas. This configuration was used to test the radar algorithm functionality. A target emulator \"traveling\" with a ten meter per second velocity at a range of 10 km was emulated over-the-air in a high-SNR, low-clutter environment. The results depicted in Figure 20. To identify potential targets, we apply a coarse matched filter in the time domain to identify the peaks associated with the direct path (blue) and the return path (red). An FFT-based time-frequency matched filter is then applied around the return peak to identify the relative velocity and range of the target. In the given environment we can clearly identify the target and correctly estimate the parameters.  
The second configuration operates with 100 MHz bandwidth at 5.8 GHz center frequency. Horn antennas were used because they were the most readily available option for the given frequency range, although directional antennas are not required to deploy this system [80]. This configuration was used to evaluate the functionality of the ToA, ranging, and synchronization features. In Figure 21, The ToA estimation standard deviation is plotted against the CRLB and fundamental resolution. After estimating the ToA, the system executes a PNT ranging and synchronization algorithm described in [13]. The results are plotted in Figures 22 and 23 as a function of integrated SNR. With this experimental configuration, we approach centimeter-level ranging precision and nanosecond-level time synchronization given sufficient signal power and waveform integration.  
While this implementation significantly underperforms custom implementations of comparable systems [13], we were able to generate a proof-of-concept prototype that validates the functionality of the various sub-systems in under a week. For reference, the final results presented in [13] are the culmination of 4 graduate students, 18 months of effort, and $1M of funding. While WISCANet does not promise the performance of a fully-custom solution, it does boast incredible speed, accessibility, and efficiency in developing functional prototypes for a variety of RF applications.  
Figure 20: Initial over-the-air results under the first experimental configuration.  
Figure 23: Over-the-air synchronization results, demonstrating sub-ns synchronization.  
Figure 21: Over-the-air time-of-arrival estimation standard deviation, plotted against the CRLB and fundamental resolution.  
Figure 22: Over-the-air ranging results, demonstrating sub-10-cm ranging precision.