# A Hybrid PAPR Reduction Method Based on SLM and Multi-Data Block PTS for FBMC/OQAM Systems
## 5 Simulation Results  
In this Section, the simulations are given to verify the analysis. The performance of the proposed method versus the traditional SLM, PTS, and simple SLM-PTS schemes are discussed. The physical layer for dynamic spectrum access and cognitive radio (PHYDYAS) filter is adopted in simulations. The complementary cumulative distribution function (CCDF) is used to measure the PAPR reduction performance. The bit error rate (BER) performance comparisons of the proposed method, the traditional SLM, PTS, and simple SLM-PTS methods are also given. The different conditions, including different numbers of phase sequences, different numbers of sub-blocks, and different numbers of data blocks, are considered for simulations. The detailed values of simulation parameters are shown in Table 1.  
Figure 5 depicts the peak-canceling signals of the proposed scheme, traditional SLM and PTS scheme, simple SLM-PTS hybrid scheme versus original signals. It can be seen that the peak powers of the signal appear at several points, and most of the remaining points have lower power. The results show that the proposed method can effectively reduce the peak power of the signal, compared to the two traditional SLM, PTS and simple SLM-PTS hybrid schemes. Figure 6 gives the PAPR reductions of the proposed method and the other three methods with \(M\) = 16, \(U\) = 4 and \(V\) = 4. The curve \"original\" denotes the CCDF of FBMC/OQAM signal without any PAPR reduction. When \(CCDF=10^{-3}\), it can be found that traditional SLM scheme can reduce the signal PAPR by about 1.6 dB, the initial PTS scheme can reduce the signal PAPR by about 1.8 dB, and the proposed method can reduce the signal PAPR by about 3.2 dB. The traditional PTS scheme outperforms the traditional SLM scheme in FBMC/OQAM systems. Obviously, these two conventional PAPR reduction \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Subcarriers \(N\) & 64 \\ Data blocks \(M\) & 8, 16 \\ Modulation & 4 QAM \\ Overlapping factor & 4 \\ Sub-blocks \(V\) & 4, 8 \\ Phase sequences \(U\) & 4, 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Simulation parameters. Figure 4: The flow chart of the proposed scheme. solutions cannot effectively reduce the PAPR of FBMC/OQAM signals. The SLM-PTS scheme provides a slightly better performance than the SLM and PTS schemes. The proposed method can achieve a PAPR improvement of 1.4 dB compared to the SLM-PTS scheme. This indicates that the proposed hybrid method based on the overlapping effect of adjacent data blocks can significantly reduce the PAPR. In the subsequent simulations, i focus on the PAPR reductions of the proposed method with different numbers of sub-blocks, different numbers of phase sequences and different numbers of data blocks. Moreover, the PAPR performances of the SLM-PTS and proposed method are also simulated under two different filter banks. Figure 7 shows PAPR reductions of the four methods with different numbers of phase sequences \(U\) and different numbers of sub-blocks \(V\). It can be found that increasing the number of phase sequences and sub-blocks can improve the PAPR reduction performance. In the SLM, PTS and simple SLM-PTS methods, increasing \(U\) and \(V\) from 4 to 8, the performance can improve by about 0.5 dB, 0.9 dB and  
Figure 5: The peak-canceling signals with four PAPR reduction methods (i.e., the proposed method, the SLM, PTS and SLM-PTS methods) versus the original signal. Figure 6: PAPR reductions by using the proposed method, the SLM, PTS and SLM-PTS methods with \(M=16\), \(U=4\) and \(V=4\). 0.8 dB, respectively. The proposed method with \(U=8\) and \(V=8\) provides the best PAPR reduction performance in the nine curves, and it can achieve a 1.2 dB performance improvement compared with the proposed method with \(U=4\) and \(V=4\), when \(CCDF=10^{-3}\) is considered.