An Application Layer Multi-Hop Collective Perception Service for Vehicular Adhoc Networks

Collective Perception will play a crucial role for ensuring vehicular safety in the near future, enabling the sharing of local perceived objects with other Intelligent Transport System Stations (ITS-Ss). However, at the beginning of the roll-out, low market penetration rates are expected. This paper proposes and evaluates an application layer multi-hop Collective Perception Service (CPS) for vehicular ad-hoc networks. The goal is to improve the environmental awareness ratio in scenarios with low CPS market penetration. In such scenarios, the CPS service without forwarding enabled struggles to achieve complete awareness. A decentralized application layer forwarding algorithm is presented that shares perceived object information across multiple hops while maintaining a low age of information. The proposed approach is compared against standard CPS with no forwarding and CPS with geographically-scoped (GBC) multi-hop forwarding. Simulations according to standards of the European Telecommunications Standards Institute (ETSI) demonstrate that the application layer forwarding achieves near 100% awareness at 10% penetration rate versus 92% for standard CPS. The awareness improvement comes with moderate channel load, unlike GBC forwarding which quickly saturates the channel. The median age of information remains below 80 ms for the proposed scheme, enabling real-time CPS operation. Our application layer multi-hop approach effectively improves environmental awareness during initial CPS deployment while aligning with latency and channel load requirements.