Aytül Bozkurt | Searcharxiv

arXiv2026

Analytical modeling and simulation validation of IEEE 802.11 DCF in vehicular-to-infrastructure networks

Vehicle-to-infrastructure (V2I) communication over IEEE 802.11 access points (APs) deployed along the roadside must operate under the contention of many vehicles sharing one channel. We investigate the transmission and network performance of vehicles passing through an AP over 802.11 WLANs. We first derive an analytical traffic model that yields the number of vehicles within the transmission range of an AP. Coupling this traffic description with a Markov-chain representation of the backoff process and an M/G/1/K queue for arriving packets, we obtain a model that evaluates DCF performance under an adaptively chosen retransmission limit, and we derive the probability of the mean arrival rate to the AP. A distinctive aspect of this work is that it integrates the vehicular traffic model and the backoff procedure with the M/G/1/K queueing model to examine the impact of traffic load and system parameters on the network. We validate the analytical framework against an independent ns-3 packet-level simulation: the throughput, collision, and transmission-probability predictions agree closely with simulation. Using the validated framework to examine the optimal retransmission number, we find that under realistic finite-buffer conditions the standard 802.11 retransmission limit is already close to optimal for delay and information freshness, so the large gains predicted by an infinite-buffer analysis do not survive packet-level validation. We report this finding explicitly and use it to delimit the operating regime in which retransmission-limit tuning is beneficial.

cs.NI↗

arXiv2026

Sensitivity-driven Adaptive Contention Window Optimization for IEEE 802.11 based V2I Networks

In vehicle-to-infrastructure (V2I) communication the setting of IEEE 802.11 Distributed Coordination Function (DCF) parameters has a decisive bearing on performance, yet the literature seldom pins down how much each parameter actually matters once traffic, MAC and queueing are modelled together. Treating a previously validated analytical framework as a fixed deterministic input-output map, we rank the DCF and traffic parameters that shape throughput, collision probability, delay, packet delivery ratio and Age of Information in a single-AP V2I network. A local one-factor-at-a-time analysis, cast in dimensionless elasticities so that parameters of different units become comparable, is paired with a variance-based global analysis built on first-order and total-effect Sobol indices. Two clean groups emerge: collision probability is set by the contending-vehicle population -- itself governed by vehicle velocity and density -- together with the minimum contention window, whereas delay is driven by the channel rate, the offered load and the packet size, and carries strong interaction effects that no local reading can expose. We then derive the closed-form structure of these sensitivities from the model relations, which explains the rankings, forces certain parameters into equal-magnitude elasticities, and locates where the local ranking reverses. Finally the collision-sensitivity structure is turned into a design output rather than a ranking: a closed-form contention-window control law, linear in the contending population and closed with a Greenshields density model, that a roadside access point can evaluate online from measured density or velocity. The fixed IEEE 802.11 default is recovered as the single population at which this law is optimal; away from it the throughput gain grows with density and is largest in the dense, safety-critical regime.

cs.NI↗