Fair access to shared radio channel in IEEE 802.11 networks

n computer networks based on a shared communication medium. the MAC (medium access control) protocol is the key element of ensuring service fairness. This element is particularly critical in wireless local area networks (WLANs), where partially hidden topologies are often encountered; for example, due to natural obstacles. The most popular wireless solutions, like IEEE 802.11 and ETSI HIPERLAN, are subject to the channel capture effect in the presence of hidden nodes. Under such conditions, the centrally located stations can send packets so frequently that the hidden nodes are jammed and cannot access the radio channel. In this paper, we analyse the channel capture phenomenon and introduce a modification of the standard 802.11 MAC protocol that attempts to alleviate this problem. Our simulation results show that the modified algorithm can significantly improve service fairness in IEEE 802.11 networks.