Enhancement of Adaptive Auto Rate Fallback with Collision Detection for IEEE 802.11n/ac WLANs

Transmission of packets in a Wireless Local Area Network (WLAN) 802.11n/ac can experience errors caused by poor channel quality. Therefore, a rate adaptation algorithm is needed which controls the selection of data rates to match the channel conditions so that packet transmission becomes successful. But in the WLAN can also occur hidden terminal problems that can cause a packet to experience the collision. In this paper, we propose enhancing the Adaptive Auto Rate Fall back with Collision Detection (AARF-CD) algorithm for rate adaptation for IEEE 802.11n/ac WLANs and call it as AARF-CD for High Throughput (AARF-CDHT). We define the new functionality and attributes needed in the AARF-CDHT algorithm. We developed and implemented our proposed algorithm according to the method of adding new modules to the NS-3 network simulator. We evaluate the performance of the AARF-CDHT algorithm through a number of simulations extensively. The simulation results show that our proposed algorithm can adapt 802.11n/ac data rate according to channel conditions and successfully activate Request to Send/Clear to Send (RTS/CTS) mode when the collision occurs in the channel. The algorithm that we propose also produces higher throughput than the comparison algorithm, based on changes in channel quality as well as based on collisions in the channel.