# GAE and OBE Enhanced Interference Mitigation Techniques in LDACS
## 5 Results and Discussions
Careful observation of these two figures reveals the fact that though OBE could reduce the impulsive noise slightly, it is not sufficient to remove the DME noise. One of the possible reasons behind this could be the minimum value of K = 2, which is used to model the received complex data. Another reason could be the scaling of data in subcarriers that are not affected by impulse noise due to the minimum value of K used for Gaussian modeling. It may be possible to overcome these two reasons either by increasing the K value in K-GMM or by applying nonlinear scaling only to the noise-affected subcarriers. Considering the computational complexity that can be associated with higher values of K, we tried to obtain better performance from 2-GMM modeling. The second possibility gives way to the development of OBE enhanced PPA. Figure 8:0 (**left**) OFDM data at the receiver along with DME interference and AWGN noise. (**right**) Output of joint GAEPPA in the time domain. Figure 8:1 Performance comparison of the proposed GAEPPA, GAEPPL1 and GAEPPL2 vs. the conventional pulse blanking. When the nonlinear scaling is applied only to selected subcarriers using (26), a reduction in BER could be achieved in comparison to pulse blanking as well as OBE. These results obtained are as displayed in Figure 8:2 Though the performance of OBE could be upgraded with the employment of OBE enhanced PPA, it is observed that attenuations applied to the affected subcarriers are not sufficient to eliminate the DME noise. It is evident from Figure 8:3 It may be possible to reduce BER even more, which leads to the development of OBE enhanced PPL. OBE enhanced PPL performed nonlinear scaling only to the subcarriers which are affected with impulse noise in such a way that the amplitude of the resulting signal after nonlinear scaling is at least equal to the threshold value used for detecting the pulse peak (30). Comparing Figure 19 (right) and Figure 20 (right), we can clearly observe that the nonlinear output displays at Figure 20 (right) are the same as those in Figure 19 with the maximum output value limited to the threshold value used for identifying the affected subcarriers. As discussed in Section 4, this operation is possible in two ways, as in (28) and (29). It is observed that the results of both of these proposed methods are the same in reducing the BER rate at the output, as the same time difference in operation can be seen in Figure 8:4  
Further joint OBE enhanced PPA and joint OBE enhanced PPL showed almost similar performance, though the actual BER value differed slightly. Both of these methods showed a significant variation in reduction of BER at the receiver compared to the pulse blanking method, which is depicted in Figure 8:5 The operation of joint OBE enhanced PPA on OFDM signal is displayed in Figure 8:6 Finally, a performance comparison between all the proposed PPAs is shown in Figure 8:7 From this result, it is identified that JOBEPPA is the best method that could mitigate DME interference among all the proposed PPAs. Similarly, Figures 25 and 26 show the comparison in different types of proposed PPLs. We can also observe that OBE enhanced methods outperformed the GAE enhanced methods, and this is expected from the literature survey. Figure 8:8 Performance comparison of the proposed joint GAEPPA, joint GAEPPL1 and joint GAEPPL2 vs. the conventional pulse blanking. Figure 8:9 (**a**) Absolute value of received OFDM data after CP removal. (**b**) Variance zero. (**c**) Probability of occurrence variance zero. (**d**) Variance 1. (**e**) Probability of occurrence variance one. Figure 7:0 (**left**) Received data packet along with DME and AWGN noise. (**right**) Output of OBE in the time domain. Figure 7:1 Performance comparison of proposed method OBE enhanced PPA with conventional pulse blanking technique and OBE. Figure 7:2 **(left)** Received data packet along with DME and AWGN noise. **(right)** Output of OBEPPA in the time domain. Figure 7:3 **(left)** Received data packet along with DME and AWGN noise.