## 5 Discussion
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Scheme of This Paper** & **C-Decision** & **SOLEN** & **GNN-RL** & **Random Action** \\ \hline Average total interference received by a high-priority link & \(-\)38.6 dB & \(-\)23.5 dB & \(-\)24.2 dB & \(-\)24.3 dB & \(-\)20.3 dB \\ \hline Average total interference received by a common link & \(-\)24.4 dB & \(-\)23.5 dB & \(-\)24.2 dB & \(-\)24.3 dB & \(-\)20.3 dB \\ \hline Average rate of V2V links & 2023 bps & 1981 bps & 2012 bps & 1726 bps & 794 bps \\ \hline Average rate of V2I links & 7205 bps & 6702 bps & 7108 bps & 6577 bps & 6348 bps \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Performance of four schemes. Figure 6: Impact of input noise on V2V links. As shown in Figure 7, in this scheme, the average rate of the V2I link decreases with the increase of input noise, and tends to be stable when the input noise is greater than 3 dB. When the input noise is large, the rate of the V2I link can still maintain 56.78%. Similarly, the average rate of V2V links decreases with the increase of input noise, and remains stable when the input noise is greater than 10 dB. When the input noise is large, the average rate of V2V links remains 82.04%. V2I links maintain better performance than V2V links. It can be seen from Figure 8 that the average interference received by the high-priority link increases with the increase of feedback noise, and there is no significant difference between the high-priority link and the ordinary link when the feedback noise is greater than 3 dB. This indicates that the effective information of link differentiation cannot be resolved when the feedback noise is high, but the priority can still be reflected when the feedback noise is low. When the feedback noise is greater than 10 dB, the average interference received by both of them is basically stable. As shown in Figure 9, with the increase of feedback noise, the average rate of the V2I link in this scheme decreases gradually, and is basically unchanged when the feedback noise is greater than 10 dB. When the input noise is large, the rate can be maintained at 85.55%. The average rate of the V2V link decreases with the increase of feedback noise, and remains stable when the feedback noise is greater than 10 dB. When the input noise is large, the average rate of the V2V link remains 57.59%. The V2I link is less affected by feedback noise. Compared with the random spectrum allocation scheme, C-Decision and SOLEN algorithm have improved transmission efficiency and anti-interference. However, C-Decision does not differentiate services between V2V links. The SOLEN scheme relies on CSI of all V2V and V2I links. The proposed scheme improves the transmission performance of high-priority links while ensuring the performance of common links, and is superior to C-Decision, SOLEN and traditional random spectrum allocation schemes in overall performance. At the same time, it has good robustness to input noise and feedback noise, and is more suitable for practical vehicle-mounted network scenarios. Figure 7: Impact of input noise on V2V links and V2I links. At present, the proposed algorithm makes centralized spectrum allocation decisions at the base station. In order to reduce computational complexity, we can consider distributed spectrum resource allocation in the next step, and each V2V link makes local spectrum allocation decisions. In the future, we will also consider improving our algorithm to be  
Figure 8: Impact of feedback noise on V2V links. Figure 9: Impact of feedback noise on V2V links and V2I links. more suitable for joint V2I link and V2V link resource allocation problems in the future Internet of vehicles.