A Practical Air Time Control Strategy for Wi-Fi in Diverse Environment

摘要

802.11 (Wi-Fi) networks are widely deployed, providing access to a huge number of users using the unlicensed spectrum. Wi-Fi users have different bandwidth capabilities based on location, interference and application requirements. Given the way Wi-Fi accesses the wireless spectrum, tests in our lab and reports in the literature showed that low bandwidth Wi-Fi users take a big portion of the air time, hindering the performance of high bandwidth users. Some vendors address this with proprietary solutions that requires special drivers and chipsets. In this paper, we design and implement a portable solution that runs on any Wi-Fi device and doesn't require modifications to the hardware or the standard protocols. We propose different air time allocation strategies exploiting the Hierarchical Token Bucket (HTB) bandwidth management capability found in any Linux distribution. Weights and air quotas are calculated for different users based on a traffic shaping strategy. Compared to normal Wi-Fi access, tests showed that the proposed solution enables a flexible control of air time allocation to contending users without the need for proprietary drivers. Moreover, the results demonstrated an improvement of the throughput ratio and stability for most of the users, hence, making better use of the unlicensed spectrum.