# A Novel Procedure of Enhancing the Throughput of a Mode-2 Sidelink Based on Partial Sensing
## 4 Simulation Results  
All the numerical results presented in this section were obtained using the sidelink functions of Release 14 (Rel-14) Long Term Evolution (LTE) provided by the MATLAB LTE Toolbox [16]. Although the proposed technique mainly targets the 5G NR, all the  
Figure 6: Timing diagram for exchanging the sensing results between RSU and P-UEs. Figure 7: Realigning of partial sensing windows for P-UEs exiting the RSU coverage. computer simulations in this study were performed for the signal environment of the Rel-14 LTE rather than the 5G NR, because the specification for the 5G NR sidelink has not yet been released. Thus, the performance of the proposed method, which employs the RSU as a collector of the partial sensing results, is compared to that of the conventional partial sensing in the signal environment of Rel-14 LTE. However, the proposed method introduced in Section 3 can be applied to the 5G NR with no changes, except that new parameter values for the 5G NR, for example, data period and/or window width, may need to be adopted. In our simulations, the data period and partial sensing duration were set to 200 and 40 ms, respectively, as specified in the Rel-14 LTE. The resource pool for the partial-sensing-based sidelink comprises subcarriers with a width of 5 MHz and a PSCCH period of 40 ms. In the case of time-division duplexing, the 40 ms PSCCH period, comprising 40 subframes, includes both the reception and transmission parts, each of which is filled with two subframes of PSCCH and 16 subframes of the physical sidelink shared channel, whereas the remaining four subframes are empty. These parameter values can be modified based on 5G NR specifications to apply the proposed technique to the 5G NR. To simulate a practical communication environment of the mode-2 sidelink, the collective perception of the environment (CPE), one of the sidelink use cases, was assumed [17]. In the assumed CPE, several P-UEs and V-UEs communicate 1600 bytes of CPE traffic with one another every 200 ms. Based on the philosophy of the partial sensing technology, that is, to reduce the battery power consumption, each P-UE checks the traffic resources occupied by all the V-UEs and the other P-UEs only for the 40 ms of the partial sensing window, instead of the entire observation period of 200 ms. Subsequently, each P-UE determines the resources that are available for use during its transmission period. All computer simulations presented in this section were performed in an urban signal environment of the mode-2 sidelink, as shown in Figure 3. The transmit power of the RSU and P-UE was 28 and 22 dBm, respectively; thus, the RSU coverage and inter-P-UE coverage were 100 and 50 m, respectively [18; 19]. Figure 8 compares the maximum possible throughput of each P-UE obtained by the proposed method to that of the conventional partial sensing method. As a reference, the throughput provided by the full sensing method is also shown. In addition, the overhead required for the proposed method to exchange the sensing information between the RSU and each P-UE is also presented. Figure 8: Throughput comparison and required overhead. To analyze the results shown in Figure 8, we first compute the number of P-UEs that can be served by the proposed method with a given resource pool. As shown above in Figure 4, to ensure that the proposed method provides the combined partial sensing results to each P-UE, each P-UE should first transmit its sensing result to the RSU (consuming two PSCCH resource blocks). Subsequently, the RSU re-transmits the combined sensing results to each P-UE (consuming additional two PSCCH resource blocks). Finally, each P-UE can transmit its traffic (consuming additional two PSCCH resource blocks) [20]. Because each of the three steps consumes two PSCCH resource blocks, each P-UE needs six PSCCH resource blocks based on the procedure of the proposed method.