A Novel Collision Avoidance Scheme Using Optimized Contention Window in Dense Wireless LAN Environments

Yoshiaki MORINO  Takefumi HIRAGURI  Hideaki YOSHINO  Kentaro NISHIMORI  Takahiro MATSUDA  

IEICE TRANSACTIONS on Communications   Vol.E99-B   No.11   pp.2426-2434
Publication Date: 2016/11/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2016EBP3056
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
IEEE802.11 MAC,  contention window,  transmission efficiency,  

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In IEEE 802.11 wireless local area networks (WLANs), contention window (CW) in carrier sense multiple access with collision avoidance (CSMA/CA) is one of the most important techniques determining throughput performance. In this paper, we propose a novel CW control scheme to achieve high transmission efficiency in dense user environments. Whereas the standard CSMA/CA mechanism. Employs an adaptive CW control scheme that responds to the number of retransmissions, the proposed scheme uses the optimum CW size, which is shown to be a function of the number of terminal stations. In the proposed scheme, the number of terminal stations are estimated from the probability of packet collision measured at an access point (AP). The optimum CW size is then derived from a theoretical analysis based on a Markov chain model. We evaluate the performance of the proposed scheme with simulation experiments and show that it significantly improves the throughput performance.