# Intelligent Dynamic Power Control with Cell Range Expansion for Small-Cells in 5G HetNets
## 4 Simulation Results  
In this section, we investigate the performance of the proposed DPC scheme for the DL of 5G HetNets using Monte Carlo simulation with Matlab simulator. We compare the proposed DPC scheme with/without DPC (Prop. DPC and Prop.) to two different schemes, i.e., conventional (Conv.) and REP in [35] as shown in Figure 4, in terms of the mean capacity and outage probability for MUEs and SUEs (including CUEs). Further, we evaluate the performance of the proposed DPC scheme in two types to show the effect of the DPC in step 2. In other words, the proposed DPC scheme (Prop. DPC) uses both CRE and DPC in steps 1 and 2, respectively, while the proposed DPC scheme without DPC (Prop.) uses only CRE in step 1. The system topology and channel assignment for the macrocell and small-cell are shown in Figures 1 and 2, respectively. The values of \(\eta\) and \(\Gamma_{sth}\) are important parameters that determine the coverage of SBSs to serve CUEs. Thus, we decided \(\eta\) = 4 and 8 dB after the experiment from \(\Gamma_{sth}\) \(-\)20 to 0 dB since we consider the coverage of SBSs to be like hotspot areas. Table 3 shows the key system parameters. Figure 5 shows the distribution of MUEs and CUEs with different values of \(\Gamma_{sth}\) and \(\eta\). The results of MUEs with \(\eta\) = 4 dB are higher than those with \(\eta\) = 8 dB. On the other hand, the results of CUEs with \(\eta\) = 4 dB are lower than those with \(\eta\) = 8 dB. The reason is that the coverage of SBSs with \(\sigma_{tmsn}^{SBS}+\eta\) increases when \(\eta\) = 8 dB and the number of CUEs offloaded from MUEs increases. In addition, the results of MUEs and CUEs are almost the same as \(\Gamma_{sth}\) increases. Figure 6 shows the distribution of SUEs and CUEs in the inner and outer zones of SBSs based on \(\Gamma_{sth}\). The number of both SUEs and CUEs in the inner zone decreases while that in the outer zone increases as the value of \(\Gamma_{sth}\) increases. The value of \(\Gamma_{sth}\) is used to assign different groups of subchannels and thus the number of SUEs and CUEs in the inner zone using the same subchannels of MBSs increases as the value of \(\Gamma_{sth}\) decreases. At the same time, the number of SUEs and CUEs in the outer zone using different subchannels of MBSs increases as the value of \(\Gamma_{sth}\) increases. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Cellular layout & Hexagonal grid, 3 sectors per cell \\ Carrier Frequency & 2 GHz \\ Bandwith & 10 MHz \\ Traffic model & Full buffer (continuous traffic) \\ Number of RBs & 50 \\ Inter site distance (\(d_{IS}\)) & 500 m [40] \\ SBS radius & 40 m \\ Number of MBSs (\(M\)) & 7 \\ Number of SBSs per cell site (\(S\)) & 4 \\ Number of MUEs per cell site (\(N\)) & 30 \\ Number of SUEs per SBS (\(T\)) & 10 \\ Total transmission power of MBSs & 46 dBm [41] \\ Total transmission power of SBSs & 30\(\sim\)37 dBm [41] \\ Path loss from MBSs to MUEs & \(128.1+37.6\log_{10}d\) dB [41] \\ Path loss from SBSs to SUEs & \(140.7+37.6\log_{10}d\) dB [41] \\ Minimum distance between MBSs and SBSs & 75 m [41] \\ Minimum distance between SBSs and SBSs & 40 m [41] \\ Minimum distance between MBSs and MUEs & 35 m [41] \\ Minimum distance between SBSs and SUEs & 10 m [41] \\ Given threshold of SUEs (\(\Gamma_{sth}\)) & \(-20\sim 0\) dB \\ Given target threshold (\(\Gamma_{sth}\)) & \(-10\) dB \\ Given CRE basis (\(\eta\)) & 4, 8 dB \\ Power control value for the REP scheme (\(\alpha\)) & 0.20 [35] \\ \(A_{mg}\) and \(A_{ma}\) & 14 dB, 20 dB [41] \\ Terminal noise level (\(\sigma^{2}\)) & \(-174\) dBm/Hz \\ \hline \hline \end{tabular}
\end{table} 
Table 3: System parameters. Figure 7 shows the results of the mean MUE capacity as the value of \(\Gamma_{sth}\) increases. We compare the results of the proposed DPC scheme to those of the conventional and REP schemes. The results of the conventional scheme show the worst performance because MUEs have strong interference from neighboring SBSs.