# Link and System-Level NOMA Simulator: The Reproducibility of Research
## 6 Validation of the MC-NOMA Simulator
### BER Analysis of Coded MC-NOMA  
In this section, the BER performance is compared for uncoded MC-NOMA and coded MC-NOMA in the presence of AWGN, impulse noise, and ICI. In the literature [36], the authors claimed that the performance of SIC can be improved by applying channel coding and LP. The proposed system model was also evaluated by varying the noise and interference cell intensities. In Figure 17, the BER comparison of conventional MC-NOMA systems with the coded MC-NOMA system is presented in the presence of a Gaussian channel. The performance of uncoded MC-NOMA and the proposed coded MC-NOMA with its linearly precoded variant was evaluated in the presence of AWGN for both NEU and FEU. Figure 17 shows that for a BER of \(10^{-3}\), \(E_{b}/N_{o}\) required for MC-NOMA with FDE-SIC is 30 dB for NEU. However, with LP, MC-NOMA with FDE-SIC, the required \(E_{b}/N_{o}\) is  
Figure 16: BER performance comparison of perfect SIC for more than 2 users in the presence of intercell interference.  
25.5 dB; which results in a gain of 4.5 dB. In another comparison for NEU, coded NOMA with FDE also achieved a gain of 4.5 dB over uncoded NOMA for a BER of \(10^{-3}\). However, when precoding is applied on coded MC-NOMA with FDE for NEU, the required \(E_{b}/N_{o}\) reaches 21 dB; resulting in a gain of 5 dB over coded NOMA-FDE. This better performance of coded NOMA is due to the energy spreading due to WHT.  
The performance of uncoded and coded MC-NOMA with and without LP was evaluated in the presence of both AWGN and impulse noise, as shown in Figure 18. Analyzing the performance of the proposed transceiver in the presence of impulse noise is important because in its presence, SIC performance becomes critical as it deteriorates the BER performance for indoor/outdoor mobile communication [37]. For the comparison presented in Figure 18, low-density impulse noise with impulse-noise-index A = 0.1 is introduced. NEU achieves, \(E_{b}/N_{o}\) equal to 38.5 dB, 33 dB, and 30 dB for coded MC-NOMA, uncoded MC-NOMA with LP, and coded MC-NOMA with LP, respectively, at a BER of \(10^{-3}\), whereas uncoded MC-NOMA is not able to reach at \(10^{-3}\). Thus, the proposed coded MC-NOMA with LP obtains a gain of 3 dB and 8.5 dB over uncoded MC-NOMA with LP and coded MC-NOMA without LP. The application of WHT in terms of LP improves the robustness of the system, whereas channel coding also enhances the error correction ability of the system and thus; results in better BER performance.  
Moreover, the ideal SIC and code-word-level SIC have almost equal performances. This validates our early assertion regarding the receiver design, as presented in Section 2, where we have also reasoned the same conclusion about the effectiveness of SIC receivers. Similarly, the throughput of the NOMA simulator can be compared with [38], which justifies the improved performance of SIC using the LP method that spreads the information conveyed by symbols into either half of the system or the entire system through the use of various transformations. This also supports the validity of the NOMA simulator. Several papers related to NOMA from our laboratory have been published in recent years [1; 23; 36; 38; 40]. Our proposed package can reproduce the majority of the figures in published papers to prove the validity of our simulator.  
Figure 17: BER comparison of un-coded MC-NOMA and coded MC-NOMA with and without WHT in the presence of AWGN only.