Dual-Zone Hard-Core Model for RTS/CTS Handshake Analysis in WLANs

TL;DR

Addresses interference and correlations in WLAN RTS/CTS handshakes by developing the dual-zone hard-core process (DZHCP). The framework yields analytical expressions for the active transmitter density $\lambda$ and mean interference $I$, and provides an MISR-based asymptotic gain $G$ to approximate the success probability $P(T)$ relative to a PPP, with explicit forms for Type I/II thinning and the special case of $R_{tx}+d<R_{cs}$. The contributions include adapted statistical measures (e.g., reduced second moment, Ripley K) for the marked model and a practical, tractable approximation $P_{DZHCP}(T)$, particularly for path loss exponent $\alpha=4$. The results enable refined interference management and design guidance for RTS/CTS parameters such as $R_{cs}$ and $R_{tx}$ in next-generation WLANs.

Abstract

This paper introduces a new stochastic geometry-based model to analyze the Request-to-Send/Clear-to-Send (RTS/CTS) handshake mechanism in wireless local area networks (WLANs). We develop an advanced hard-core point process model, termed the dual-zone hard-core process (DZHCP), which extends traditional hard-core models to capture the spatial interactions and exclusion effects introduced by the RTS/CTS mechanism. This model integrates key parameters accounting for the thinning effects imposed by RTS/CTS, enabling a refined characterization of active transmitters in the network. Analytical expressions are derived for the intensity of the DZHCP, the mean interference, and an approximation of the success probability, providing insight into how network performance depends on critical design parameters. Our results provide better estimates of interference levels and success probability, which could inform strategies for better interference management and improved performance in future WLAN designs.

Figures (13)

• Figure 1: Illustration of a transceiver pair employing the RTS/CTS mechanism, showing the dual-zone exclusion regions for interference management. The transmitter (T) and receiver (R) are separated by a distance $d$. The orange region, with radius $R_{\mathrm{cs}}$, corresponds to the physical carrier sensing range, which prevents nearby transmitters from causing interference at the transmitter (T). The green region, with radius $R_{\mathrm{tx}}$ and centered at the receiver (R), denotes the RTS/CTS virtual carrier sensing region, which protects the receiver from potential interference by blocking transmissions within this zone.
• Figure 2: Illustration of a bipolar model with RTS/CTS signaling and Type i@ thinning. In this model, each transmitter (represented as a black square) is paired with a corresponding receiver (depicted as a white circle). Active links are shown with solid red arrows, representing the connections that remain functional after the RTS/CTS thinning process. Suppressed links, depicted by dashed black arrows, represent connections that are blocked or "thinned" to prevent interference with neighboring active links, in accordance with the RTS/CTS mechanism.
• Figure 3: Spatial distribution of two transceiver pairs showing their respective exclusion regions.
• Figure 4: SIR ccdf for the dual-zone hard-core process and MISR-based approximation for $\lambda_p=1\times10^{-4} {\rm m}^{-2}$.
• Figure 5: SIR ccdf for the dual-zone hard-core process and MISR-based approximation for $\lambda_p=5\times10^{-5} {\rm m}^{-2}$.

Theorems & Definitions (8)

• Theorem 1
• proof
• Theorem 2
• proof
• Lemma 1
• proof
• Theorem 3
• Corollary 1