## 7 Hardware Implementation  
The proposed joint radar jamming and communication system was validated on a SDR (the specific model was USRP X310, as shown in Figure 15) in a controlled laboratory environment to acquire data and evaluate its radar jamming and communication capabilities. The SDR generates integrated signals for radar jamming and communication tasks. The prototype is highly flexible since all parameters can be set, and the feasibility of the proposed waveform design was demonstrated. The specific experimental configuration and scenario are shown on the left side of Figure 15, consisting of a personal computer (PC) and a USRP. The internal signal processing flow of SDR is displayed on the right side.  
The parameters were set as follows: signal bandwidth was 50 MHz, pulse repetition frequency (PRF) was 1 kHz, the number of UFMC sub-bands was 5, the communication  
Figure 14: The CFAR results under different \(\eta\): (**a**) the result of \(\eta=3:1\); (**b**) the result of \(\eta=7:1\); (**c**) the result of \(\eta=31:1\); (**d**) the local magnification of (**c**).  
Figure 15: Experimental platform and signal processing flow: SDR and PC.  
jamming interweaving ratio \(\eta\) was 1:1, and 4 QAM was the selected modulation scheme. Data were collected on the PC to complete SAR imaging simulation and communication BER testing. The jamming echo data received by SDR were superimposed on the SAR imaging echo at the PC, and the results are shown in Figure 16.  
Figure 16a shows the SAR imaging results without jamming, and it can be seen that the imaging results are clearly visible at this time. Figure 16b,c, respectively, show the occurrence of false targets before and after the real target by setting the frequency shift of jamming signals. Figure 16d,e show the results of increasing the number of jamming signals to perform multiple false target jamming. Figure 16d is an extended version of Figure 16b, and Figure 16e is the extended result of Figure 16c. Under the influence of jamming, the image's contrast is decreased and the detail information is covered by jamming, leading to multiple false targets in the range dimension.  
Based on the above results, it can be seen that the integrated waveform of UFMC chirp proposed in this article can effectively jam with radar, and the leading or lagging positions of false targets are controllable, increasing the effectiveness of jamming. The BER result of communication is shown in Figure 17.  
In Figure 17, the blue diamond line represents the theoretical BER of 4 QAM, the red hexagonal line represents the simulation results on the PC end, and the yellow star line and purple circle line represent the presence and absence of equalization BER in USRP, respectively. From the graph, it can be seen that as the SNR increases, all BER values show a downward trend. The PC simulation results are similar to the theory, but the imperfect equilibrium makes it impossible to match the theory. By comparing the BER curves of USRP, it can be seen that the BER performance has been improved after jamming signal assisted equalization. However, there is still some error between the measured results and the simulation results, which is due to the hardware damage of SDR itself and the complex and enclosed laboratory environment. When the SNR is greater than 15 dB, the BER is lower than \(10^{4}\), which can effectively complete the communication task.  
Figure 16: SAR imaging results: (**a**) without jamming; (**b**) frequency shift jamming causes the result to appear before the real target; (**c**) frequency shift jamming causes the result to appear after the real target; (**d**) the result of increasing the number of jamming attempts on the basis of (**b**); (**e**) the result of increasing the number of jamming attempts on the basis of (**c**).  
The SDR experimental test results show that the proposed joint radar jamming and communication waveform have the ability to simultaneously achieve radar jamming and communication.