###### Abstract  
The reliability of V2X (vehicle-to-everything) communication is important for safe automated driving. With the advances in wireless communication and multipath transport protocols, a vehicle can employ multiple wireless interfaces and carry out multipath communication. Although there has been extensive research into increasing the Quality of Service (QoS) performance, such as throughput and delay in V2X communication, few studies have addressed explicit ways of improving the reliability of vehicle-to-cloud (V2C) communication through multipath-based redundancy. This paper addresses the issue of improving V2C reliably via multipath-based packet duplication, with particular consideration given to redundancy mitigation. We propose a method that employs dynamic adjustment of multipath redundancy to maintain packet-delivery reliability in V2C communication while enabling redundancy mitigation. The evaluation results show that the proposed method allows the vehicle to maintain the desired reliability in terms of successful packet transmission while reducing redundancy caused by packet duplication in a multipath connection. vehicle to cloud (V2C); vehicle to everything; reliability; redundancy; multipath +
Footnote †: journal: Applied  
2024 14 28  
of V2C communication and overcome the reliability limit of data transmission on a V2C path. (3) On the other hand, multipath-based packet transport with duplicated packet transmission also incurs the potential problem of redundancy in data transmission due to the concurrent use of multiple paths. Redundant utilization of multiple paths causes the consumption of wireless resources at the vehicle side and increased traffic load at the cloud side. Therefore, this paper addresses the issue of enabling both end-to-end V2C reliability and mitigating path redundancy for multipath-based duplicated packet delivery in V2C communication. We propose a multipath V2C method that controls multipath redundancy to improve and maintain the reliability of packet transmission. Packet duplication is carried out by the concurrent use of multiple paths, leading to resilience to packet losses in a single path. Furthermore, to reduce the redundancy of duplicated packet transmission, redundancy mitigation is achieved with the proposed method via dynamic adjustment of the number of paths adopted in multipath transmission. The dynamic adjustment of the path number is based on the sensing of packet losses at the receiver side. At the vehicle side, a vehicle first relays the target reliability and packet transmission schedule to the cloud server. During V2C communication, the vehicle dynamically chooses the number of paths based on the assessment results of reliability and redundancy obtained from the cloud server. The cloud server assesses the packet losses at each path and periodically judges the reliability by comparing it with the target reliability. In order to support path redundancy adjustment, the cloud server informs the vehicle of the reliability results, which enables vehicles to adjust the necessary number of redundant paths. The contributions of this study are as follows: (1) As far as we know, we are the first to address the issue of improving the reliability of V2C communication via multiple paths with both packet duplication and mitigation of path redundancy. (2) Taking into account the features of V2X and advances in multipath transmission, detailed algorithms are designed for the vehicle side and the cloud server side. The proposed method allows for cooperation between vehicles and the cloud through the exchange of information about the transmission schedule, packet loss status, and information related to path redundancy adjustment. (3) Explicit examinations of the effectiveness of the proposed method are carried out using theoretical analysis and computer simulations.