Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit
IEEE/ACM Transactions on Networking (TON)
Analytical models for single-hop and multi-hop ad hoc networks
Mobile Networks and Applications - Special issue: Recent advances in wireless networking
Performance modelling and measurements of TCP transfer throughput in 802.11-based WLAN
Proceedings of the 9th ACM international symposium on Modeling analysis and simulation of wireless and mobile systems
Modeling the 802.11 distributed coordination function in nonsaturated heterogeneous conditions
IEEE/ACM Transactions on Networking (TON)
New insights from a fixed-point analysis of single cell IEEE 802.11 WLANs
IEEE/ACM Transactions on Networking (TON)
Performance analysis under finite load and improvements for multirate 802.11
Computer Communications
Performance analysis of the IEEE 802.11 distributed coordination function
IEEE Journal on Selected Areas in Communications
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Analytical models of IEEE 802.11-based WLANs are invariably based on approximations, such as the well-known mean-jield approximations proposed by Bianchi for saturated nodes. In this paper, we provide a new approach for modeling the situation when the nodes are not saturated. We study a State Dependent Attempt Rate (SDAR) approximation to model M queues (one queue per node) served by the CSMA/CA protocol as standardized in the IEEE 802.11 DCF. The approximation is that, when n of the Mqueues are non-empty, the attempt probability of the n non-empty nodes is given by the long-term attempt probability of n saturated nodes as provided by Bianchi's model. This yields a coupled queue system. When packets arrive to the M queues according to independent Poisson processes, we provide an exact model for the coupled queue system with SDAR service. The main contribution of this paper is to provide an analysis of the coupled queue process by studying a lower dimensional process and by introducing a certain conditional independence approximation. We show that the numerical results obtained from our finite buffer analysis are in excellent agreement with the corresponding results obtained from ns-2 simulations. We replace the CSMA/CA protocol as implemented in the ns-2 simulator with the SDAR service model to show that the SDAR approximation provides an accurate model for the CSMA/CA protocol. We also report the simulation speed-ups thus obtained by our model-based simulation.