TCP Over Target Wakeup Time

The Target Wake Time (TWT) feature introduced in 802.11ax can be employed to achieve higher power efficiency, reduced channel access contention, and lower network congestion by scheduling clients' transmissions. Despite these potential benefits, because TWT allows communication during service periods only, it can negatively impact the Transmission Control Protocol (TCP) performance. In this paper, we identify and discuss the impact of TWT on TCP performance for RTOS and Linux-based wireless devices and show that TWT leads to unnecessary retransmissions, which wastes channel bandwidth and increases communication delay and energy consumption. To address this problem, we propose and implement a method to share TWT operational parameters with the TCP layer to adjust its packet loss detection method. Empirical evaluations across different hardware platforms confirm the effectiveness of the proposed approach in preventing premature packet loss detection and reducing unnecessary retransmissions.