Fair round robin binary countdown to achieve QoS guarantee and fairness in WLANs

摘要

How to guarantee both quality of service (QoS) and fairness in wireless local area networks (WLANs) is a challenging issue. To touch this issue, a fair medium access control (MAC) scheme called fair round robin binary countdown (FRRBC) adopting the eminent concepts of allowance and binary countdown is proposed in this paper. FRRBC can guarantee QoS for both audio and video with the aid of adaptive adjustment on system parameters and some extra rules designed according to delay bounds. Using multiple mapping functions from allowances to fixed-bit binary numbers to indicate different priorities, FRRBC not only provides guaranteed system performance but also achieves good fairness. Finally, we demonstrate that FRRBC can significantly outperform the enhanced distributed channel access (EDCA) (IEEE 802.11 WG in IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part Ⅱ: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements, 2005) and the synchronized medium access control (SYN-MAC) (Wu HY et al. in Mobile Netw Appl 11:627-637, 2005) because of its superiority to offer guaranteed QoS for both audio and video, low delay jitter, low blocking ratio, and good fairness. Of course, FRRBC can be illustrated to be a better choice than the enhanced distributed elastic round robin (EDERR) (Ferng HW, Liau HY in IEEE Trans Mobile Comput 8(7):880-894, 2009).