Stochastic modelling and analysis of 802.11 DCF with heterogeneous non-saturated nodes

The Distributed Coordination Function (DCF) in the IEEE 802.11 protocol is a random access scheme based on the carrier sense multiple access with collision avoidance (CSMA/CA). In recent years, there have been numerous research on the performance analysis and modelling of DCF under the assumption that the transmission queue is always nonempty (i.e. saturation state). In this paper, we propose a stochastic analysis approach to study the operation of the DCF in the non-saturation state. We also consider the fact that most 802.11 deployments use the infrastructure mode of operation in which all traffic is routed through an access point; this implies that access points will have much more traffic to transmit than the clients. within this realm, we allow for asymmetric finite rate clients to account for the heterogeneous nature of the wireless Access points. Our modelling approach is an extension of that described in Winands et al. [E. Winands, T. Denteneer, J. Resing, R. Rietman, A finite-source feedback queueing network as a model for the IEEE 802.11 DCF, in: Eur. Trans. Telecommun. 16 (1) (2005) 77–89], which is an adaptation of the homogeneous finite-source machine repair queueing model.