Implementation and Evaluation of IEEE 802.11ax Channel Sounding Frame Exchange in ns-3

To enable extremely high throughput in wireless local area networks (WLANs), new features including Multi-User Multiple-Input Multiple-Output (MU-MIMO), beamforming techniques, and coordinated beamforming among multiple access points (APs) have been considered in current and future standards. All of these features require stations to measure the wireless channel and feed back channel state information (CSI) to APs. However, it is still impractical to evaluate system-level performance of these techniques in ns-3 since the functionality of CSI acquisition is missing. In this paper, an ns-3 implementation of channel sounding process in medium access control (MAC) layer based on IEEE 802.11ax is described. Simulation results are presented to show the overhead of the channel sounding process and provide a first step toward evaluating the impact of channel sounding on network performance.