Understanding Multi-link Operation in Wi-Fi 7: Performance, Anomalies, and Solutions

Will Wi-Fi 7, conceived to support extremely high throughput, also deliver consistently low delay? The best hope seems to lie in allowing next-generation devices to access multiple channels via multi-link operation (MLO). In this paper, we aim to advance the understanding of MLO, placing the spotlight on its packet delay performance. We show that MLO devices can take advantage of multiple contention-free links to significantly reduce their transmission time, but also that they can occasionally starve one another and surprisingly incur a higher delay than that of a well planned legacy single link operation. We next examine and explain this anomaly, also putting forth practical workarounds to circumvent it. We conclude by pointing to other disruptive features that, if successfully paired with MLO, can usher in exciting and unprecedented opportunities for Wi-Fi 8.