Use of Channel Occupancy for Multi Link WiFi 7 Scheduler Design in ns-3

The newest WiFi standard, WiFi 7, has introduced Multi Link Operation (MLO) that enables WiFi devices to utilize multiple links simultaneously (asynchronous mode). This is particularly significant in view of the fact that WiFi network traffic is increasingly multi-class or heterogeneous, implying that future network optimization must simultaneously address multiple Key Performance Indicators (KPIs) - throughput, reliability, latency. Such a feature will enable provisioning for strict latency constraints of new applications like augmented/virtual reality in the presence of (usual) throughput-oriented best-effort traffic. Thus, the availability of MLO naturally leads to innovative MLO scheduler design approaches that aim to appropriately allocate traffic across various links in response to current link state.Network performance evaluation of such new scheduler designs continue to rely heavily on network simulations such as ns-3 (www.nsnam.org). Broadly speaking, there exists a need to expose common heuristics to such MLO schedulers to enable exploration of data-driven, in-simulation MLO optimization approaches. In that spirit, we describe the ns-3 implementation of the channel occupancy (CO) metric, intended to serve as a measure of link congestion. We validated our implementation by comparing against appropriate analytical models and subsequently suggest approaches to novel MLO scheduler designs that utilize CO, via a few illustrative examples.