# A Novel Procedure of Enhancing the Throughput of a Mode-2 Sidelink Based on Partial Sensing
## 4 Simulation Results
Because 50 PSCCH resource blocks exist within the resource pool of 5 MHz bandwidth, the maximum number of P-UEs per 40 ms partial sensing window is 8 (= 50/6); thus, at most 40 (= 8 \(\times\) 5) P-UEs can exist for the entire observation period of 200 ms. Figure 8 illustrates the values for throughputs provided to each of the P-UEs by the full sensing method, conventional partial sensing method, and proposed method, together with the overhead incurred in the proposed method. In this figure, it can be observed that, as the number of P-UEs increases from two to five, the maximum throughput that can be provided to each P-UE increases proportionally with the number of P-UEs in the proposed method. Importantly, each P-UE can exploit the sensing results of the other P-UE and its sensing result without overlapping, as long as the number of P-UEs does not exceed five. In contrast, the throughput of the conventional partial sensing method decreases as the number of P-UEs increases. The major reason for this is that the CPE traffic must increase as the number of P-UEs increases. Although an increase in CPE traffic occurs in the case of the proposed method, the simulation results show that the effect of the CPE traffic increase is almost negligible compared to the benefit of providing the combined sensing results. Furthermore, the throughput of each P-UE starts decreasing as the number of P-UEs exceeds five. The main reason for this is that, when the number of P-UEs exceeds five, the additional benefit of combining the partial sensing results obtained from more than five P-UEs is negligible because the number of partial sensing windows that can be combined is fixed to five; thus, the combination of the partial sensing results from more than five P-UEs is no longer helpful. Moreover, the overhead required to exchange the sensing results between the RSU and each of the P-UEs, and the CPE traffic, increases as the number of P-UEs further increases. Regarding the overhead shown in Figure 8, because 1 PSSCH resource block is needed for transmitting the sensing result from the P-UE to RSU, and three resource blocks are needed for transmitting the results back from RSU to each P-UE, the total overhead can be obtained easily from the formula given in [15]. The throughput provided by the full sensing method was approximately five-fold that of the conventional partial sensing method. This is because, as mentioned earlier, usable resources can be selected during the entire 200 ms observation period, which is five times longer than the 40 ms partial sensing window. The slight inferiority of the proposed method compared to full sensing mainly results from the overhead required for the proposed method to exchange the partial sensing results between the RSU and each of the P-UEs. In terms of the benefit of reducing the power consumption provided by the proposed method, however, the slight difference in the achievable throughput between the full sensing and proposed methods is negligible. In practice, the importance of the battery life of each P-UE cannot be overemphasized. As shown in Figure 8, when the number of P-UEs is five, the throughput of each P-UE provided by the proposed method (4.187 Mbps) is approximately five-fold that of the conventional partial sensing method (0.847 Mbps). The superiority of the proposed method remains consistent even when the number of P-UEs increases up to 40, with results of 1.786 Mbps (proposed) versus 0.434 Mbps (conventional). We present the application of the proposed method of combining the partial sensing results to the case when the total number of P-UEs exceeds 40 during the observation period of 200 ms. In the proposed method described in Section 3, all the P-UEs transmit the RSU partial sensing results such that the RSU re-transmits the combined sensing results to each P-UE. Generally, the partial sensing result provided by every P-UE within a given 40 ms time slot would be almost the same because each partial sensing procedure is performed within a given RSU coverage.