Muyuan Shen

This letter studies the latency–power trade-off of various multi-link operation (MLO) traffic-allocation mechanisms – probability-based, greedy, and single link (SL) – using ns-3 simulations under both symmetric and asymmetric link conditions. We jointly consider mean and 99th-percentile (p99) end-to-end (E2E) latency as well as average power consumption of multi-link devices (MLDs). Results show that the greedy scheme achieves the lowest latency in symmetric traffic scenarios by exploiting simultaneous multi-link access, albeit with moderately higher power consumption. Conversely, under asymmetric link quality or background load, the probability-based method effectively collapses to single-link operation, attaining both minimal latency and lowest power. Our analysis sheds important light on adaptive traffic allocation for latency-sensitive and power-constrained Wi-Fi 7 applications.

As a groundbreaking feature in IEEE 802.11be, multi-link operation (MLO) is expected to support emerging applications that are strongly delay-sensitive. A key to the effective use of MLO for such cases rests on the optimal allocation of application traffic across multiple links. Our initial simulation experiments in ns-3 reveal that the proposed traffic allocation policies in prior art are significantly sub-optimal in terms of achievable delay performance of multi-link devices (MLDs), particularly in the presence of legacy single-link devices (SLDs). In this work, we first develop a new analytical model for the mean end-to-end (E2E) delay, delay jitter and worst-case percentile latency performance of MLD-SLD-coexisting Wi-Fi 7 networks (largely unexplored to date) with saturated and unsaturated SLD traffic. Subsequently, the optimal traffic allocation strategies for minimizing the mean E2E delay and delay jitter are obtained and validated by ns-3 simulation results. It is shown that with the optimal policy, MLDs can achieve significantly better mean E2E delay, delay jitter, worst-case latency and delay cumulative distribution function (CDF) compared to existing solutions.

Wi-Fi is evolving towards enhanced support for real-time applications such as video conferencing and virtual reality (VR) gaming. The latest IEEE 802.11be draft standard introduces various advancements including multi-link operation (MLO) at the medium access control (MAC) layer. Such multi-link operation (effectively carrier aggregation) is anticipated to increase data throughput, and reduce access delay. Notably, the recent release of the ns-3 network simulator (ns-3.41) incorporates an implementation of MLO, enabling novel simulation-based analysis on the potential impact of link scheduling strategies on network delay. This paper begins with validation of end-to-end delay for the MLO implementation in ns-3 in a baseline scenario, and then proceeds to explore the impact of different link allocation strategies. Our observations reveal that across diverse scenarios, the outcomes derived from ns-3 align consistently with our theoretical model.