An Experimental Study of Latency for IEEE 802.11be Multi-link Operation

TL;DR

This study evaluates how Multi-Link Operation (MLO) in Wi-Fi 7 can significantly reduce latency under certain conditions, but may increase it in others, and proposes an enhancement to mitigate this.

Contribution

The paper provides experimental insights into MLO's latency effects and introduces Opportunistic STR+ channel access to improve performance.

Findings

MLO can reduce latency by an order of magnitude in symmetric channel occupancy.

In asymmetric channels, MLO may increase latency.

Opportunistic STR+ can mitigate latency issues in asymmetric conditions.

Abstract

Will Multi-Link Operation (MLO) be able to improve the latency of Wi-Fi networks? MLO is one of the most disruptive MAC-layer techniques included in the IEEE 802.11be amendment. It allows a device to use multiple radios simultaneously and in a coordinated way, providing a new framework to improve the WLAN throughput and latency. In this paper, we investigate the potential latency benefits of MLO by using a large dataset containing 5 GHz spectrum occupancy measurements. Experimental results show that when the channels are symmetrically occupied, MLO can improve latency by one order of magnitude. In contrast, in asymmetrically occupied channels, MLO can sometimes be detrimental and increase latency. To address this case, we introduce Opportunistic Simultaneous Transmit and Receive (STR+) channel access and study its benefits.