Stochastic Geometry Analysis of Inversely Proportional Carrier Sense Threshold and Transmission Power for WLAN Spatial Reuse

Takayuki NISHIO

IEICE TRANSACTIONS on Communications   Vol.E104-B    No.10    pp.1345-1353
Publication Date: 2021/10/01
Publicized: 2021/03/31
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2020EBT0009
Type of Manuscript: PAPER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
IEEE 802.11ax,  spatial reuse,  carrier sense threshold,  stochastic geometry,  

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In this paper, a stochasic geometry analysis of the inversely proportional setting (IPS) of carrier sense threshold (CST) and transmission power for densely deployed wireless local area networks (WLANs) is presented. In densely deployed WLANs, CST adjustment is a crucial technology to enhance spatial reuse, but it can starve surrounding transmitters due to an asymmetric carrier sensing relationship. In order for the carrier sensing relationship to be symmetric, the IPS of the CST and transmission power is a promising approach, i.e., each transmitter jointly adjusts its CST and transmission power in order for their product to be equal to those of others. This setting is used for spatial reuse in IEEE 802.11ax. By assuming that the set of potential transmitters follows a Poisson point process, the impact of the IPS on throughput is formulated based on stochastic geometry in two scenarios: an adjustment at a single transmitter and an identical adjustment at all transmitters. The asymptotic expression of the throughput in dense WLANs is derived and an explicit solution of the optimal CST is achieved as a function of the number of neighboring potential transmitters and signal-to-interference power ratio using approximations. This solution was confirmed through numerical results, where the explicit solution achieved throughput penalties of less than 8% relative to the numerically evaluated optimal solution.