# Information Relaying Methods in VANET: Algorithms, Standards and Tests
###### Abstract  
This paper considers information transmission issue observed in a large scale test of cellular-based vehicular to everything (C-V2X) technology in China, which is the information blockage for the vehicle-to-vehicle (V2V) wireless communication. With such findings, we propose utilizing relaying-based information routing solutions by the support of K-means-type algorithm and an on-request relay selection method in a vehicular adhoc network (VANET). From the algorithm perspective, we refine the K-means-based VANET seeding principle with considerations on the global vehicle layout. On the other hand, base station and/or core network aided relay selection associated with vehicle maneuver is introduced for waking up relays when necessary in order to address the typical non-line-of-sight (NLOS) signal attenuation by taking the power consumption into consideration. To evaluate the system performance, we conduct Matlab and network simulator (NS)-3 simualtions to justify the algorithms, and adopt Veins-based simulations to show the data packets loss gain over non-relaying scenarios of realistic V2V scenario with NLOS signal dissemination. C-V2X; VANET; K-means; relay; NLOS; Veins +
Footnote †: journal: Applied  
_articles_  
_Article_  
Information Relaying Methods in VANET: Algorithms, Standards and Tests. _Applied_  
**Citation:** [PERSON]; [PERSON]; [PERSON] Information Relaying Methods in VANET: Algorithms, Standards and Tests. _Appl. Sci._**2022**, 12, 10748. [[https://doi.org/10.3390/app122110748](https://doi.org/10.3390/app122110748)]([https://doi.org/10.3390/app122110748](https://doi.org/10.3390/app122110748))  
Academic Editor: [PERSON]  
Received: 26 July 2022  
Accepted: 13 September 2022  
Published: 24 October 2022  
**Published:** **Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. **Cognitive**: 2022 by the authors. Liconse MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/)]([https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/))). **Copyright**: \(\copyright\) 2022 by the authors. Liconse MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/)]([https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/))). **1. Issuesfrom Real-World Tests**  
In recent years, in order to pave the way for the upcoming C-V2X commercialization, International Mobile Telecommunications (5G), IMT-2020 (5G) for short, has launched a series of C-V2X tests within China, promoting the C-V2X technology to the real road test and discovering new potential issues. With our developed C-V2X hardware, i.e., onboard unit (OBU) and roadside unit (RSU) in Figure 1c,d it is of great treasure for Sony for its very first attempt in a C-V2X real-world interoperability test in Wuhan, November 2021. During the 2-day activities, we observed the NLOS signal attenuation as a threat to the real deployment of C-V2X technology. A wide variety of reasons may be concluded including limited bandwidth, flooding data packets, and, the trickiest one, obstacles in the transmission path. Bushes, trees, buildings and even vehicles could become obstacles in V2V communications, leading to NLOS signal attenuation as a threat to the real deployment of C-V2X technology. Therefore, relaying-aided signal dissemination approaches (e.g., our location-based one) becomes fairly necessary to overcome the information blockage. The test field is located in Wuhan economic development district, a blocked T-junction road area with 200 OBUs installed around to simulate C-V2X packet transmission in a crowded traffic area.