Joint Design of L-MAC Transmission Mechanism and U-MAC Packet Scheduling for NSTR MLO Operations in Wi-Fi 7

Abstract

To enhance user experience, IEEE 802.11be introduces Multi-Link Operation (MLO), enabling improved throughput performance by simultaneously utilizing two or more links. To mitigate In-Device Coexistence (IDC) interference, Multi-Link Devices (MLDs) can employ Non-Simultaneous Transmit and Receive (NSTR) MLO. The performance of NSTR MLO is highly influenced by environmental factors such as channel occupancy, making it essential to devise and adopt NSTR MLO algorithms that align with specific user environments. This paper proposes several NSTR MLO algorithms for U-MAC packet scheduling (specifically, OPA) and for L-MAC packet transmission (specifically, EATX, SATX-C, SATX-A, and ATX), and provides a comprehensive experimental evaluation of various NSTR MLO algorithms to identify their optimal performance across diverse conditions. Using a MATLAB-based in-house MLO simulator, we assess the performance of NSTR MLO algorithms under different environmental scenarios. The evaluation reveals that NSTR MLO with Alternating Transmission (ATX) is well-suited for most cases, while NSTR MLO with Start-time Aligned Transmission (SATX) is optimal in environments with low channel occupancy and bursty traffic arrivals. Moreover, the results show that the proposed OPA algorithm for U-MAC significantly enhances the performance of an MLD using SATX under high channel occupancy environments.