# Analytical Framework of CP-Free Multiuser OFDM System for Coordinated Multi-Point at mmWave
## 3 Simulation Results
To meet up a typically assumed BER of \(10^{-4}\), \(-2.5\) dB and \(4\) dB SNR are required for a linear amplifier and \(12\) dB IBO with HPA, respectively, in the case of user 1, as shown in Figure 19. In the case of user 2, for the same BER of \(10^{-4}\), \(-1.7\) dB and \(3.8\) dB SNR are required for linear amplifier and \(12\) dB IBO with HPA, respectively, as depicted in Figure 20. For user 3 in Figure 21, the SNR requirement is found to have values of \(-2.2\) dB and \(4.2\) dB. In comparison with the systems without IBO-based HPA linearity, the BER performance in the case of user 4 for different values of IBO is moderate, as shown in Figure 22.  
Figure 17: Power spectral density of the considered system with the implementation of \(16-\)QAM higher\(-\)order digital modulation, RA channel coding, and CHT schemes for the cases of (**a**) user 1, (**b**) user 2, (**c**) user 3, and (**d**) user 4. Figure 18: Estimated PAPR at different transmitting channels of serving BSs and IBO under nonlinear HPA implementation. Figure 19: BER performance of the considered system with and without implementation of IBO-based HPA for the case of user 1. Figure 20: BER performance of the considered system with and without implementation of IBO-based HPA for the case of user 2. Figure 19: BER performance of the considered system with and without implementation of IBO-based HPA for the case of user 1. The authors in [36] made a comparative study on the suitability of a Walsh-Hadamard transformed (WHT) universal-filtered multicarrier (UFMC) system with classical OFDM and UFMC systems in terms of BER and SNR performance. The authors in [37] established improved performance of a double-tree complex wavelet transform (DTCWT)-based OFDM system in combination with the fast WHT (FWHT) and eliminated the drawbacks of the OFDM system. In [38], authors recommended a zero tail inverse lifting wavelet transform spread FWHT OFDM (ZT-ILWTs FWHT OFDM) system as an alternative to the conventional OFDM and presented better performance of their proposed system in terms of BER, PAPR, and OOB emission. In Figure 23, a comparative analysis has been illustrated in terms of BER against SNR between our proposed CoMP-JT-based mmWave CP-free multiuser OFDM system, WHT UFMC/fast WHTs and DTCWT-based OFDM, and ZT-ILWTs FWHT OFDM multicarrier signaling technique implemented systems. For a better view of the obtained values, Table 5 is also added. Under the scenario of systems without any channel coding scheme, the presented numerical results of our proposed uncoded system for a typically assumed case of user 1 is reasonably acceptable in comparison with the works of the other systems for BPSK, QAM, and 16-QAM digital modulations. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{3}{*}{**SNR (dB)**} & \multicolumn{6}{c}{**Bit Error Rate (BER)**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Proposed System**} & \multicolumn{2}{c}{**WHT Spread**} & \multicolumn{2}{c}{**DTCWT–FWHT**} & \multicolumn{2}{c}{**ZT-ILWTs FWHT**} \\  & \multicolumn{2}{c}{**UFMC System**} & \multicolumn{2}{c}{**OFDM System**} & \multicolumn{2}{c}{**OFDM System**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Digital Modulation**} & \multicolumn{2}{c}{**Digital Modulation**} & \multicolumn{2}{c}{**Digital Modulation**} \\ \cline{2-7}  & **16-QAM** & **QAM** & **BPSK** & **16-QAM** & **QAM** & **BPSK** \\ \hline \(-5\) & 0.051 & 0.033 & 0.016 & 0.390 & 0.200 & 0.096 \\ \(-3\) & 0.022 & 0.014 & 0.006 & 0.360 & 0.120 & 0.066 \\ \(0\) & 0.003 & 0.002 &