## 4 Simulation Results and Analysis
### Analysis of Simulation Results
#### 4.1.1 Comparative Analysis of Access Rate and Throughput  
A comparative analysis was conducted, referencing [33; 50], focusing on access rates pertaining to VUEs. The non-access rate for VUEs is defined as the proportion of instances where the data rate falls below the predetermined target, relative to the total number of VUEs. The findings, depicted in Figure 3, indicate a correlation between the increase in the number of VUEs and a subsequent rise in the non-access rates for all algorithmically-managed VUEs, consequently leading to a decrease in the overall access rate.  
In contrast, the observed access rate in this study exceeds that of the comparative literature. In this particular study, it was found that out of the total 60 VUEs, the non-access rate was determined to be 25%. Consequently, this indicates that there were 45 VUEs that were accessible, accounting for 75% of the total VUEs. In comparison, the non-access rates of the references [33; 50] are 54% and 44%, respectively, resulting in accessible counts of 28 and 34 VUEs for both references. This implies that 46% and 56% of the VUEs (28 and 34 VUEs) may be accessed correspondingly. Upon analyzing the curve trend depicted in Figure 3, it becomes evident that there is a notable increase in the performance disparity  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value Size** \\ \hline Channel model & 3 GPP Highway \\ Radius size & 500 m \\ Depolyment & 3 lanes \\ Antenna height & 1.6 m \\ Carrier frequency & 2 GHz \\ Noise power & \(-\)174 dBm \\ Channel bandwidth & 10 MHz \\ CUEs quantity & 3, 5, 7, 9 \\ Vehicle speed & 60–110 km/h \\ Vehicle distribution & Poisson distribution \\ Shadow standard deviation & 8 dB (CUEs), 3 dB (VUEs) \\ CUEs path loss & 128.1 + 37.6 log (d [km]) \\ VUEs path loss & LOS inWINNER + B1 \\ \(W_{j}^{max}\) & 23 dBm \\ \(W_{j}^{max}\) & 23 dBm \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameters.  
between the comparative literature and the present study. Although this solution effectively meets the data rate requirements for CUEs and VUEs, it imposes a constraint on the access rate of VUEs. This limitation arises from the allocation of only one subcarrier to each pair of VUEs.  
For the throughput, this study compares throughput using a multiaccess matching method for resource allocation, with references [51; 52], where the resource allocation adopts a many-to-one matching scheme; that is, multiple VUEs can use the same subcarrier, and one subcarrier only allows one VUE to use. The random algorithm in [51; 52] randomly assigns spectrum resources and power sizes. The comparison, illustrated in Figure 4, indicates a notable enhancement in total VUEs' throughput with the algorithm proposed in this paper. Specifically, when \(\Psi_{j}^{size}=5\) for all CUEs, the system data rate of the CUEs hovers around 58.74 (bps/hz) as the number of VUEs increases. In contrast, the data rate of the CUEs in [51; 52] gradually decreases with an expanding VUEs count since they do not impose data rate constraints on the CUEs. The proposed algorithm prioritizes meeting CUEs' data rate requirements before resource allocation, employing multiaccess channel matching to fully utilize spectrum resources. Consequently, the total throughput of both VUEs and CUEs systems in this paper surpasses that of the comparative literature. Notably, due to a limited number of subcarriers (V = Y = 9), escalating VUEs result in cumulative interference, causing the system throughput to plateau in later stages.  
Figure 4: Comparison of the VUEs throughput.  
Figure 3: Comparison of VUEs’ un-access rate.