# A Packet Collision Reduction Based on Reselection for LTE V2X Mode 4
## 4 Numerical Examples
### Numerical Results  
Figure 11 shows a comparison between the conventional scheme and the proposed methods for generation pattern 1. \"No interference\" indicates the case of the interference-free, and this curve shows the upper bound of PRR.  
The proposed PA method can obtain a higher PRR than the conventional scheme in a long range of each UE. We expect that the PA method can reduce packet collisions when the transmitter is far from the receiver. The PA method enables the UEs to increase the released resources to \(\mathbb{S}_{B}\). Since \(\mathbb{S}_{B}\) is composed of the resources in ascending order of the RSSI, it is possible to exclude the resources, which is expected to be used by other UEs and whose RSSI is evaluated to be small, from \(\mathbb{S}_{B}\). In particular, other UEs that use the resource, evaluated to be small RSSI, are located far from the UE because the evaluation of the RSSI depends on only the distance between the UEs. On the other hand, the proposed OA method can obtain a higher PRR than the conventional scheme in the short range of each UE. We expect that the OA method can reduce packet collisions when the transmitter is at a short distance from the receiver. The OA method can avoid the same resource selection for the UE that transmits the packet with \(P_{rsp}=0\). This is effective for UEs located at a short distance from the transmitter because it is possible to obtain \(P_{rspp}\) from the received packet easily. Fortunately, we can make use of the proposed PA and OA methods at the same time without additional information and specific constraints. The combination method obtains higher PRR than the conventional scheme in the short and long range of each UE. Because the two methods interact with each other, it is possible to obtain a high PRR in any range. In addition, each proposed method always obtains the same or better performance as the conventional scheme. This is because the proposed method operates in the same way as the conventional scheme if there is no notification of \(P_{rsp}=0\).  
Figure 11: Effect of the PRR for generation pattern 1.  
two methods. Furthermore, no deterioration in performance was confirmed. The main contribution of this paper is to make effective use of the information contained in \(P_{\textit{resp}}\) used in the SPS wireless resource allocation algorithm. Although various methods have been studied to improve the performance of the wireless resource allocation problem by using additional information, these methods require extensions that do not conform to the standard. In contrast, this research utilizes \(P_{\textit{resp}}\) that have been used in standards to improve performance while maintaining compatibility. The greatest advantage of this method is that it can be introduced without modifying existing standards. We also propose two methods for utilizing \(P_{\textit{resp}}\), the PA and OA, and their fusion method, which always outperforms the performance of each of them alone. Our method is designed to maintain compatibility with existing standards, so it may or may not have a significant effect, but there are no disadvantages.  
For future work, we are studying the effectiveness of the proposed methods in different scenarios such as effects of the channel fading and shadowing, UE density, and road model including the NLOS environment.  
Writing--original draft, M.A.; Writing--review & editing, M.F. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.