Age of Information Under DCC Rate Constraints for V2I Broadcast Along Urban Corridors

Hyperbolic density dependence and a cooperative policy for DCC-constrained V2I broadcast

Yousef AlSaqabi· 2026· DOI 10.48550/arXiv.2606.29611

The core problem

Vehicle-to-infrastructure (V2I) broadcast along urban corridors underpins safety and traffic-efficiency applications, but ETSI Decentralized Congestion Control (DCC) throttles roadside unit (RSU) broadcast rates according to channel load. Although DCC is designed to keep channel busy ratio (CBR) below a target, its effect on the freshness of V2I updates—quantified by age of information (AoI)—has remained uncharacterized under real traffic. This work closes that gap by deriving the AoI of DCC-constrained V2I broadcast and evaluating it on a large-scale empirical trace. The central finding is that AoI depends hyperbolically on vehicle density, producing diurnal swings exceeding a factor of four on a four-RSU corridor, with the DCC target CBR as the dominant control parameter. To mitigate this, the paper proposes a cooperative policy that exploits upstream spatial traffic correlation to improve channel load estimation, with a safeguard guaranteeing non-negative gains. Evaluated on a 5-day, 762,050-vehicle trace from Kuwait City, the policy reduces corridor AoI by 5% at moderate and up to 66% at conservative DCC settings.

The derived AoI exhibits a hyperbolic dependence on vehicle density, which translates into strong diurnal variation. On the four-RSU corridor, AoI varies by more than a factor of four over a day, with the DCC target CBR identified as the dominant control parameter. The cooperative policy, evaluated on the 5-day, 762,050-vehicle Kuwait City trace, reduces corridor AoI by 5% at moderate DCC settings and up to 66% at conservative DCC settings. The safeguard ensures that the cooperative policy never degrades performance relative to baseline DCC. These results demonstrate that exploiting upstream spatial traffic correlation can substantially improve information freshness without violating DCC constraints.

Vehicle-to-infrastructure (V2I) broadcast along urban corridors underpins safety and traffic-efficiency applications, but ETSI Decentralized Congestion Control (DCC) throttles roadside unit (RSU) broadcast rates according to channel load. Although DCC is designed to keep channel busy ratio (CBR) below a target, its effect on the freshness of V2I updates—quantified by age of information (AoI)—has remained uncharacterized under real traffic. This work closes that gap by deriving the AoI of DCC-constrained V2I broadcast and evaluating it on a large-scale empirical trace. The central finding is that AoI depends hyperbolically on vehicle density, producing diurnal swings exceeding a factor of four on a four-RSU corridor, with the DCC target CBR as the dominant control parameter. To mitigate this, the paper proposes a cooperative policy that exploits upstream spatial traffic correlation to improve channel load estimation, with a safeguard guaranteeing non-negative gains. Evaluated on a 5-day, 762,050-vehicle trace from Kuwait City, the policy reduces corridor AoI by 5% at moderate and up to 66% at conservative DCC settings.

The methodology combines analytical derivation with trace-driven evaluation. First, the AoI of a DCC-constrained V2I broadcast is derived as a function of vehicle density and the DCC target CBR. The analysis reveals a hyperbolic density dependence, which can be expressed as:

The hyperbolic density dependence implies that AoI is highly sensitive to traffic fluctuations, making static DCC configurations suboptimal for corridors with pronounced diurnal patterns. The cooperative policy addresses this by using upstream spatial correlation to refine channel load estimation, effectively anticipating downstream congestion. The safeguard is critical: it prevents the cooperative estimate from worsening AoI when correlation is weak or misleading. The 5-66% AoI reduction shows that the benefits are largest under conservative DCC settings, where baseline AoI is highest. This suggests a trade-off: stricter congestion control improves channel reliability but degrades freshness, and cooperation can recover much of that loss. The findings are specific to a four-RSU urban corridor in Kuwait City, but the methodology—deriving AoI under DCC and applying a safeguarded cooperative policy—is generalizable to other corridors and DCC parameterizations. Future work could extend the analysis to multi-corridor networks and dynamic DCC targets.

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