## 4 Simulation and Results  
This section discusses the performance results of the proposed SRC-Log and the comparison results with the ten state of the art precoding-companding techniques (i.e., DHT-\(A\)[26], SRC-\(\mu\)[37], DCT-\(\mu\)[33], DFT-\(\mu\)[28], DST-\(\mu\)[32], DHT-\(\mu\)[24], WHT-\(\mu\)[22], WHT-\(exp\)[23], DST-\(A\)[31], and ZCT-\(\mu\)[34]) in terms of PAPR reduction gain, BER, OOB radiation reduction, and EVM. Moreover, the PAPR reduction performance of SRC-Log is compared with PTS. Parameters of the simulation are given in Table 1.  
Firstly, the PAPR reduction performance of SRC-Log is compared with the conventional SRC precoding and conventional Log companding, as shown in Figure 3. Figures 4 and 5 show the comparative performance of SRC-Log with conventional SRC precoding and conventional Log companding in AWGN channel and Rayleigh channel, respectively. As expected, SRC-Log has better PAPR reduction and BER performance than SRC precoding and Log companding. However, extra computational complexity is the price of performance enhancements, as shown in Table 2 that is based on (17) and (19). \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline No. Subcarriers (\(N_{T}\)) & 256 \\ No. Data subcarriers (\(N_{DSC}\)) & 192 \\ Oversampling value (L) & 4 \\ Model of HPA & SL \\ Modulation (order-type) & 16-QAM \\  & 64-QAM \\ Channel model & AWGN channel \\  & Rayleigh channel \\  & 16-QAM: 4/2 (AWGN/Rayleigh) \\ IBO (dB) & 64-QAM: 5/4 (AWGN/Rayleigh) \\ Channel Estimation & Ideal \\ Decoder Type & Hard Decision Decoding \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of simulation parameters. Figure 3: PAPR reduction capability comparison between proposed SRC-Log technique and conventional SRC precoding and Log companding techniques. Figure 4: BER performance of SRC-Log in AWGN channel in comparison with SRC precoding and Log companding, along with OFDM w/o PAPR reduction. The case of an ideal amplifier is shown in a solid line. Figure 5: BER performance of SRC-Log in Rayleigh channel in comparison with SRC precoding and Log companding, along with OFDM w/o PAPR reduction. The case of an ideal amplifier is shown in a solid line. It is observed in 16-QAM (Figures 4a and 5a) that SRC precoding has better BER performance than Log companding, while in 64-QAM (Figures 4b and 5b) SRC precoding has worse BER performance than Log companding. This is because precoding techniques have PAPR reduction performance depends on modulation order. This can be observed in Figure 3, where SRC precoding has better PAPR reduction performance than Log companding in 16-QAM (Figure 3a) and worse than in 64-QAM (Figure 3b). Figure 6 shows the comparison results of the PAPR reduction capability of SRC-Log with the ten state of the art precoding-companding techniques (i.e., DHT-\(A\)[26], SRC-\(\mu\)[37], DCT-\(\mu\)[33], DFT-\(\mu\)[28], DST-\(\mu\)[32], DHT-\(\mu\)[24], WHT-\(\mu\)[22], WHT-\(exp\)[23], DST-\(A\)[31], and ZCT-\(\mu\)[34]). As shown in Figure 6a,b, in 16-QAM and 64-QAM PAPR reduction performance is almost similar. Clearly, in 16-QAM and 64-QAM DHT-\(\mu\), DST-\(\mu\), and WHT-\(\mu\) are better than DHT-\(A\), DST-\(A\), and WHT-\(exp\). This is because \(\mu\)-law companding has PAPR reduction performance better than \(A\)-law companding and \(exp\) companding [10]. Not surprisingly, ZCT-\(\mu\), DFT-\(\mu\), DHT-\(\mu\), and DST-\(\mu\) have PAPR reduction performance better than SRC-Log. As, \(\mu\)-law companding has PAPR reduction performance better than Log companding, especially at low PAPR values. However, at high PAPR values, Log becomes hardly better than \(\mu\)-law. Although ZCT-\(\mu\), DFT-\(\mu\), DHT-\(\mu\), and DST-\(\mu\) have PAPR reduction performance better than SRC-Log, this does not mean they are better than SRC-Log because PAPR reduction performance is not the primary metric to determine the best technique. Especially when working with the techniques that cause BER degradation as a PAPR reduction cost, such as companding techniques.