Most studies on performance of IEEE 802.11 distributed
coordination function (DCF) have proved that the binary
exponential backoff (BEB) algorithm suffers from low throughput,
long transmission delays and low transmission reliability, for
a high traffic load. In this paper, we propose a two-phase contention window (TPCW) access mechanism that enhances the aggregate throughput and transmission reliability while decreasing the medium access delay. In addition, this scheme aims at being
computationally simple. This work characterizes the performance
of the TPCW mechanism for different parameterization values.
An analytical model is proposed for the TPCW access mechanism, which characterizes the frame transmission reliability, the total transmission delay and the aggregate throughput. The validity of our analytical model is verified through extensive simulations. By comparing the performance results, we conclude that the proposed scheme can significantly enhance IEEE 802.11 in terms of frame transmission reliability, total transmission delay and aggregate throughput.