Safe Carrier Sensing Range in CSMA Network under Physical Interference Model

TL;DR

This paper determines the necessary carrier-sensing range in 802.11 networks under the physical interference model to prevent collisions, revealing it must be larger than under the pairwise model by a specific factor.

Contribution

It introduces a new analysis of carrier-sensing range under the physical interference model, quantifying the required increase over the pairwise model.

Findings

Carrier-sensing range must be larger under the physical interference model.

The required factor depends on SINR and path-loss exponent.

The maximum factor approaches 1.84 as SINR increases.

Abstract

In this paper, we study the setting of carrier-sensing range in 802.11 networks under the (cumulative) physical interference model. Specifically, we identify a carrier-sensing range that will prevent collisions in 802.11 networks due to carrier-sensing failure under the physical interference model. We find that the carrier-sensing range required under the physical interference model must be larger than that required under the protocol (pairwise) interference model by a multiplicative factor. For example, if the SINR requirement is 10dB and the path-loss exponent is 4, the factor is 1.4. Furthermore, given a fixed pathloss exponent of 4, the factor increases as the SINR requirement increases. However, the limit of the factor is 1.84 as the SINR requirement goes to infinity.