## 5 Simulation Results and Discussion
### Simulation Results and Discussion  
This subsection presents a comparative performance analysis of the resource management method without FFR scheme (RRM), resource management with greedy heuristic scheme (RM-WGHRMS) and resource management with binary power control scheme (RM-WBPCS). Figure 4 shows the CDF of the SINR for DPs, CUs, and the overall system. We can see from Figure 4a that the GHRMS and BPCS allocate uplink resources to DPs that fulfill the SINR requirements. Thus, the SINR of DPs in our proposed method is higher than those in both resource management method without FFR scheme and resource management method with GHRMS. However, Figure 4b shows that the SINR of CUs in our proposed method is less than the SINR of DPs. This is because of the matter that CUs experiences interference from DPs. Finally, Figure 4c shows that the overall system SINR distribution of our proposed scheme achieves the highest value. We observed that the proposed scheme outperforms the other schemes in terms of SINR. Figure 5 presents the achievable capacity distribution for DPs, CUs, and the overall system. From Figure 5a, we can denote that the capacity distribution of DPs for our proposed scheme has the best performance. In contrast, from Figure 5b, we can observe that the capacity distribution of CUs is less than that of DPs. This result arises from the fact that the CUs experienced interference from co-channel DPs. In addition, we can observe from Figure 5c that the proposed scheme has the best capacity among existing schemes, since a larger frequency reuse factor increases the capacity of the system. Moreover, \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Cell outline & Hexagonal framework \\ Number of cells & 7 \\ Noise power density & \(-174\) dBm/Hz \\ Distance between D2D transmitter and receiver & 1-70 m \\ Carrier frequency & 2 GHz [31] \\ Uplink bandwidth & 5 MHz [31] \\ Path-loss exponent & 4 \\ Antenna type & 120\({}^{\circ}\) directional antenna \\ Number of CUs per cell & 65 \\ Number of DPs per cell & 80 \\ Number of iterations & 10,000 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Primary simulation parameters. Figure 4: CDF of the SINR for **(a)** DPs, **(b)** CUs, and **(c)** the overall system. the results depicted in Figure 5 show that the FFR scheme assures the QoS requirements for DPs and CUs and achieves the optimal resource reuse partner between CUs and DPs. The CDFs of the spectral efficiency for DPs, CUs, and the overall system are shown in Figure 6, respectively. Figure 6a shows that our proposed scheme has the best spectral efficiency for DPs among the existing schemes. Moreover, Figure 6b demonstrates that the proposed scheme yields a higher spectral efficiency for CUs compared to the other schemes. In addition, we can see from Figure 6c that our proposed scheme attains the highest overall system spectral efficiency; since the proposed resource management with GHRMS combined with the BPCS increases the spectrum utilization of the cell. In Figure 7, the average throughput of our proposed scheme is compared with existing schemes. Figure 7a demonstrates that the throughput of DPs increases significantly with varying number of DPs. In contrast; Figure 7b shows that the throughput of CUs decreases dramatically with increasing DP number, which occurs because an increased DP number generates high uplink interference for  
Figure 5: Total achievable capacity for **(a)** DPs, **(b)** CUs, and **(c)** the overall system. Figure 6: CDF of the spectral efficiency for **(a)** DPs, **(b)** CUs, and **(c)** the overall system. traditional CUs. But, we can see from Figure 7c that the overall system throughput increases with varying number of DPs and that our proposed scheme outperforms the other schemes. The throughput increases with the increase of number of active DPs in a cell at first, then after reaching a peak number of affordable active DPs, the throughput saturates.