STREAM: Medium Access Control With Station Presence Awareness in Crowded Networks

In this article, we propose a medium access control (MAC) scheme, called STation pREsence-Aware MAC (STREAM), that offers equal contention opportunities to the stations in a network. STREAM is designed to preserve its performance in crowded and high-traffic networks. The scheme improves channel access, utilization, and service fairness of stations. STREAM detects collided transmissions or idle events in the network to estimate the number of active stations. STREAM sets the contention period as a function of the number of stations in the network. As a result, the number of contention opportunities is enlarged and the access to the transmission channel in the network is improved. In this way, STREAM overcomes the performance degradation of IEEE 802.11 under heavy traffic and crowded networks. We analyze the throughput of STREAM, fairness of service, and the probability that a station experiences collisions as a function of the number of stations in the network. We also present performance evaluations and comparisons with IEEE 802.11 and other high-performing schemes. We extend the application of STREAM on traffic with different priorities and quality of service. Our evaluations show that STREAM outperforms IEEE 802.11 and the compared schemes. We show that STREAM is an ideal candidate as a fallback mechanism for IEEE 802.11 under overwhelming conditions.