Implementation and Evaluation of IEEE 802.11ax TargetWake Time Feature in ns-3

The TargetWake Time (TWT) feature has been introduced in Wi-Fi technology in 802.11ah and has been extended by IEEE 802.11ax as an optional feature. It allows stations (STAs) to sleep for some intervals and wake up at a Target Wake Time to send and receive their traffic. This feature reduces energy consumption of devices. While the standards are completed, there is no publicly available implementation of TWT in a simulation framework. The contribution of this paper is a description of the TWT feature and its implementation in the Network Simulator-3 (ns-3) as an integration into the existing Wi-Fi module. We describe the structure of the implementation and report on test suites that have been provided to ensure the correct operation of the code. In addition, we carried out some simple experiments that illustrate the effect of TWT. The implementation will be part of the official Wi-Fi module of ns-3 and can be utilized for systematic evaluation of the TWT feature and for novel Wi-Fi management concepts that leverage TWT.