Application Delay Modelling for Variable Length Packets in Single Cell IEEE 802.11 WLANs

In this paper, we consider the problem of modelling the average delay experienced by an application packets of variable length in a single cell IEEE 802.11 DCF wireless local area network. The packet arrival process at each node i is assumed to be a stationary and independent increment random process with mean ai and second moment a(2) i . The packet lengths at node i are assumed to be i.i.d random variables Pi with finite mean and second moment. A closed form expression has been derived for the same. We assume the input arrival process across queues to be uncorrelated Poison processes. As the nodes share a single channel, they have to contend with one another for a successful transmission. The mean delay for a packet has been approximated by modelling the system as a 1-limited Random Polling system with zero switchover times. Extensive simulations are conducted to verify the analytical results.

💡 Research Summary

The paper addresses the long‑standing problem of analytically characterizing the average end‑to‑end delay experienced by application‑level packets of variable length in a single‑cell IEEE 802.11 Distributed Coordination Function (DCF) wireless LAN. While many prior works have focused on fixed‑size packets or have assumed simple Poisson arrivals, real‑world traffic exhibits both bursty arrival patterns and a wide distribution of packet sizes. To capture these realities, the authors model the packet arrival process at each node i as a stationary independent‑increment process characterized by a mean arrival rate a_i and a second moment a_i^{(2)}. This generalizes the Poisson assumption and allows for traffic with higher variability.

Packet lengths at node i are modeled as independent and identically distributed (i.i.d.) random variables P_i with finite first and second moments, *E