Modified Rate Control for Collision-Aware in Minstrel-HT Rate Adaptation Algorithm

摘要

The rate adaptation algorithm in the IEEE 802.11 Wireless Local Area Networks (WLANs) is used to control the rate for frame transmission. In the Linux kernel, Minstrel-HT is used as the default rate adaptation to control the rate in the IEEE 802.11n/ac WLANs. But if there are frames collisions in the channel caused by the hidden terminal problem, then Minstrel-HT degrade data rate resulting in throughput also become decreased. The use of RTS/CTS transmission mode in Minstrel-HT is based on RTS-Threshold, resulting in throughput also decreasing as transmission overhead increases when there are no collisions in the channel. Previous works have proposed dynamic RTS/CTS activation method but it is only used for legacy WLANs. In this paper, we propose a modified rate control in Minstrel-HT that takes into account the development of PHY and MAC in the IEEE 802.11n/ac WLANs and we call it as Minstrel with Collision Detection for High Throughput (Minstrel-CDHT). The modifications we propose are as follows, if the transmission is not successful, then the first retransmission is done by enabling RTS/CTS mode. If the transmission fails again, it is assumed that the failure is not caused by the collision and the following retransmission is done by disabling RTS/CTS mode. We implement and evaluate this algorithm using NS-3 network simulator. The simulation results show, when the collision occurs in the channel, our proposed algorithm produces higher throughput than the original Minstrel-HT and Minstrel-HT with static RTS/CTS.