# A Novel Procedure of Enhancing the Throughput of a Mode-2 Sidelink Based on Partial Sensing
## 4 Simulation Results
That is, when more than one P-UE is assigned for partial sensing within a single time slot, the partial sensing results reported to the RSU by all the P-UEs must overlap with one another. The partial sensing result of one P-UE would be different from that of another only when the P-UEs are located far away from each other within the RSU coverage, such that they afford distinct partial sensing results. Based on this analysis, every P-UE in each 40 ms time slot need not send the partial sensing result to the RSU. In an extreme case, only one P-UE in each 40 ms time slot is assigned to report its partial sensing result to the RSU, whereas all the other P-UEs in the corresponding 40 ms time slot do not transmit their partial sensing results to the RSU such that they do not occupy the corresponding resources of the two PSCCH resource blocks. Consequently, the maximum number of P-UEs per 40 ms partial sensing window can be increased to 11, meaning that up to 55 P-UEs can exist for the entire observation period of 200 ms. With this modification of the proposed method, the overhead required for exchanging the partial sensing results between the RSU and each P-UE is also considerably reduced. Table 1 shows the number of P-UEs that can be served by the proposed method according to the number of P-UEs reporting their partial sensing results to the RSU. As the number of reporting P-UEs decreases, although the overhead also decreases, the maximum throughput of each P-UE remains almost the same as that in Figure 8, where all the P-UEs in each 40 ms time slot report their partial sensing results to the RSU. Although the collision probability must increase as the number of reporting P-UEs decreases, as shown in Figure 9, the impact of reducing the number of P-UEs is not negligible unless this number is reduced to one. This result is consistent with that of the earlier analysis regarding the overlap among the partial sensing results reported by multiple P-UEs in a given 40 ms time slot. Figure 10 illustrates the collision probability as the number of reporting P-UEs varies from one to eight. It is worth noting that the collision probability was computed under the assumption that the 200 ms observation period is occupied by the maximum supportable number of P-UEs for each case, that is, 55, 55, 50, 50, 45, 40, or 40 P-UEs are to be served, where the number of reporting P-UEs at each 40 ms time slot is 1, 2, 3, 4, 5, 6, 7, or 8, respectively, as shown in Table 1. As shown in Figure 10, the collision probability rapidly decreases as the number of reported P-UEs exceeds one. When only one P-UE reports its partial sensing result to the RSU, the collision probability in the signal environment considered in this study was found to be 22.5%. The collision probability is significantly reduced as the number of reporting P-UEs exceeds one; therefore, the throughput performance shown in Figure 9 is comparable to that of Figure 8 unless the number of reporting P-UEs is one. Consequently, the number of reporting P-UEs, which should not be one, as discussed above, does not exceed two in the signal environment considered in this study; thus, the total number of supportable P-UEs can be increased to 55, as shown in Table 1. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline Number of reporting P-UEs/40 ms & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\ partial sensing window & 55 & 55 & 50 & 50 & 45 & 45 & 40 & 40 \\ observation period & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The number of P-UEs that can be served by the proposed method according to the number of P-UEs reporting their partial sensing results to the RSU.