## 6 Simulation Experiments and Performance Analysis
### The Trade-Off between Radar Jamming and Communication Performance  
To highlight the impact of different interleaving factors on the radar jamming and communication capabilities of the joint signal, a comprehensive analysis was undertaken, involving systematic variations in the interleaving ratio between the two constituent components. The process of signal interleaving increases the number of frequency-domain sampling points, resulting in periodic extension in the time domain of the joint signal. The  
Figure 12: The results of multi-false-target jamming under MTD and CFAR. The leftmost column (**a**,**d**) is the result of target echoes processed by MTD under the two cases; the second column (**b**,**e**) is the magnified MTD results; the third column (**c**,**f**) is the comparison of CFAR threshold. ratio of interleaving between communication and jamming frequency points is given by the expression:  
\[\eta=\frac{N_{com}}{N_{jam}} \tag{50}\]  
where \(N_{com}\) represents the number of communication interleaving, and \(N_{jam}\) is the number of jamming interleaving. Let \(N_{total}=N_{com}+N_{jam}\). When the interleaving ratio is \(\eta\), the time-domain duration of the joint signal will extend by a factor of \(N_{total}\) compared to the original. At the communication receiver, when \(\eta\leq 1\), the communication system can use jamming signal frequency points adjacent to communication frequency points for auxiliary channel equalization. Conversely, if \(N_{com}\) is less than \(N_{jam}\), it results in a decrease in the communication rate of the joint signal. When \(\eta>1\), where \(N_{com}\) is greater than \(N_{jam}\), the communication rate of the joint signal increases, but the jamming signal frequency points are spaced significantly apart from the communication signal frequency points. In frequency selective fading channels, the effectiveness of auxiliary channel equalization gradually deteriorates with the increase in \(\eta\), resulting in a degradation of communication performance. The communication BER performance curves under different \(\eta\) are depicted in Figure 13.  
In Figure 13, the blue hexagonal line, red cross line, yellow circular line, and purple plus sign line correspond to BER curves under the condition \(\eta\leq 1\), while the green hexagonal line, blue pentagram line, and brown rhombus line depict the BER curves under the condition \(\eta>1\). Upon comparing the results in Figure 13, it can be observed that when \(\eta\leq 1\), the BER performance is comparable across various interleaving scenarios. However, once \(\eta>1\), the BER performance degrades, and as \(\eta\) continues to increase, the BER performance deteriorates further. At the jammed radar end, under the condition of constant energy in the joint signal, the energy entering the radar within the time corresponding to the accumulated pulse count will decrease to \(1/N_{total}\). This reduction leads to a decrease in \(J_{SNR}\), causing a degradation of the jamming performance of the joint signal. Consequently, it fails to effectively obscure the true position of the target. The radar CFAR processing results obtained for different values of \(\eta\) are illustrated in Figure 14.  
Figure 14a,b depict CFAR results for \(\eta=3:1\) and \(\eta=7:1\), respectively, while Figure 14c illustrates CFAR outcomes for \(\eta=31:1\). Figure 14d provides a magnified display of Figure 14c. Analysis of Figure 14 suggests that, with the power of the joint signal held constant, an incremental increase in \(\eta\) results in a gradual reduction in the jamming capability of the signal until it can no longer mask the true target. This decline occurs as the number of jamming signal frequency points exceeds that of communication frequency points, a consequence of the periodic extension in the time domain, leading to a reduction  
Figure 13: The BER results under different \(\eta\). in \(J_{SNR}\).