Spatial Reuse in IEEE 802.11ax WLANs
Dealing with massively crowded scenarios is one of the most ambitious goals of next-generation wireless networks. With this goal in mind, the IEEE 802.11ax amendment includes, among other techniques, the Spatial Reuse (SR) operation. This operation encompasses a set of unprecedented techniques that are expected to significantly boost the performance of Wireless Local Area Networks (WLANs) in dense environments. In particular, the main objective of the SR operation is to maximize the reutilization of the medium by increasing the number of parallel transmissions. Nevertheless, due to the novelty of the operation, its performance gains remain largely unknown. In this paper, we first provide a gentle tutorial of the SR operation included in the IEEE 802.11ax, which is exhaustively overviewed. Then, we analytically model SR and delve into the new kind of inter-WLAN interactions that appear as a result. Finally, we provide a simulation-driven analysis of the potential of SR in a variety of deployments, comprising different network densities and traffic loads. Our results show that the SR operation can significantly improve the medium reutilization, especially in scenarios under high interference conditions. Moreover, we highlight the non-intrusive design feature of SR, which is meant for enhancing the number of simultaneous transmissions without affecting the environment. We conclude the paper by drawing some conclusions on the main challenges and limitations of the SR operation included in the IEEE 802.11ax, as well as on the research gaps and future directions.
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