Collision-Aware Rate Adaptation Algorithm for High-Throughput IEEE 802.11n WLANs

IEEE 802.11n Wireless Local Area Network (WLAN) is the default standard that is used on modern smartphones and modern PCs/laptops. Medium Access Control (MAC) 802.11n has the capability of transmitting multiple MAC Protocol Data Units (MPDUs) into an Aggregate-MPDU (A-MPDU). Physical (PHY) 802.11n transmits MPDU or A-MPDU using a PHY rate of 6.5 to 600 Mbps determined by the rate adaptation algorithm. The selected PHY rate is expected according to the channel conditions for MPDU to be received without error. Based on the literature study, Minstrel-HT is one of the rate adaptation algorithms based on proposed channel conditions, especially for IEEE 802.11n high-throughput WLAN. However Minstrel-HT does not have a mechanism to activate RTS/CTS mode dynamically in the event of a collision error. Collision-aware rate adaptation (CARA) has been proposed, however the design has been made not for WLAN high throughput. In this paper we improve CARA to take advantage of MAC and PHY 802.11n capabilities and call it CARA for High Throughput (CARA-HT). We developed the CARA-HT algorithm in NS-3.26 simulator. The simulation results show the throughput produced by CARA-HT is better than Minstrel-HT.