Evaluation of RTOT algorithm: A first implementation of OBSS_PD-based SR method for IEEE 802.11ax
Tanguy Ropitault · 2018
The main goal of the IEEE 802.11ax project is to improve the network efficiency of IEEE 802.11 systems in dense deployments. There are currently several methods under consideration in the IEEE 802.11ax task group to achieve the aforementioned goal, including Multi-User Multiple Input Multiple Output (MU-MIMO), Multiple Packet Data Unit-aggregation, channel bonding, in addition to several Spatial Reuse (SR) improvements strategies. In this paper, we focus on the SR improvements methods and more specifically on one of the proposed solution at IEEE to improve SR for 802.11ax: Overlap Basic Service Set Physical Detection (OBSS_PD)-based SR. This solution combines adjusting the power transmission and Carrier Sense Threshold (CST) in order to increase the number of successful concurrent transmissions in dense networks. In this article, we propose and evaluate the RSSI To OBSS Threshold (RTOT) algorithm which is, to the best of our knowledge, the first algorithm to implement OBSS_PD-based SR technique. RTOT uses the beacon Received Signal Strenght Indicator (RSSI) to dynamically compute the CST, and derive afterwards the transmission power to use. We evaluate RTOT algorithm by simulation in a dense scenario. We show that the overall system throughput can be improved up to 80 % compared to IEEE 802.11 legacy networks. We highlight that the overall throughput improvement comes at the expense of per-station throughput degradation, and thus the fairness among stations is severely compromised. A trade-off must be considered between maximizing the overall throughout and maintaining an acceptable per-station throughput.