Quiet CTS: CTS Power Control for Better Spatial Reuse in Wi-Fi

This paper sheds light on the necessity for transmit power control of 802.11 clear-to-send (CTS) frame for better spatial reuse in densely deployed wireless local area networks (WLANs). We first study the effect of the interference caused by CTS frames through both experiments and numerical analysis. Based on the analysis, we raise a limited spatial reuse problem caused by RTS/CTS mechanism and establish a guideline for controlling CTS transmit power to solve the problem. Next, a standard-compliant CTS transmit power control method, namely Quiet CTS (QCTS), is proposed. Through extensive simulations and prototyping using both software-defined radio and commercial devices, we demonstrate that QCTS enhances the average network throughput by up to 50% by enabling more simultaneous data transmissions.