RATIO: Redundancy-Controlled Stochastic Routing for Reliable Vehicular Multi-Hop Networking

2026-06-15

AI Summary

This work addresses the challenges of low reliability in multihop transmission and difficulty in redundancy control caused by high node mobility and frequent link disruptions in highly dynamic vehicular networks. To tackle these issues, the authors propose RATIO, a novel routing mechanism that constructs a weighted directed acyclic graph and introduces, for the first time, a continuously controllable stochastic redundancy scheme. By leveraging modular arithmetic to enable non-integer path replication, RATIO overcomes limitations of conventional approaches and achieves fine-grained trade-offs between redundancy and reliability. Furthermore, a heuristic algorithm, H-RATIO, is designed by integrating local scoring with iterative optimization. Extensive SUMO/ns-3 co-simulations demonstrate that RATIO and H-RATIO significantly outperform baseline methods under high traffic loads, achieving the highest timeliness-aware packet delivery ratio and transmission efficiency.

Abstract

Reliable, low-latency multi-hop data delivery in vehicular networks is increasingly demanded, yet remains challenging due to frequent route failures caused by high mobility and intermittent blockage. While redundancy-based routing enhances robustness by forwarding packets over multiple paths, over-replication intensifies contention and introduces additional delay, highlighting the need to carefully managing redundancy--reliability trade-off. However, conventional deterministic multi-path replication typically duplicates packets to an integer number of branches, making the redundancy level hard to tune and adapt to time-varying network dynamics in vehicular networks. To this end, Redundancy-Controlled Stochastic (RATIO) routing is proposed in this paper. For each active flow, RATIO constructs a weighted reduced directed acyclic graph (DAG) as the routing structure, where edge weights specify per-link forwarding probabilities. At fork nodes, the aggregate outgoing forwarding probability is allowed to exceed one and a modulo-based stochastic forwarding rule is employed to guarantee feasible forwarding, thereby enabling continuously controllable redundancy. An idealized RATIO design is formulated as a load-minimizing optimization subject to per-flow timely-reliability and link-capacity constraints, but the problem is generally intractable under time-varying wireless dynamics. Accordingly, a practical heuristic, termed H-RATIO, is developed. H-RATIO constructs a compact reduced DAG by taking the union of candidate paths and optimizes forwarding probabilities via local scoring and replication-adjustment iterations. Extensive trace-driven SUMO/ns-3 co-simulations demonstrate that RATIO/H-RATIO consistently achieves the highest timely PDR compared to baselines, while providing substantially better delivery efficiency, especially under high-load scenarios.

Problem

• vehicular networks
• multi-hop routing
• redundancy control
• reliability-latency trade-off
• stochastic forwarding

Innovation

• stochastic routing
• redundancy control
• vehicular networks
• directed acyclic graph (DAG)
• timely reliability