Simple and Effective Carrier Sensing Adaptation for Multi Rate Ad-Hoc MESH Networks

Abstract

Adaptive physical carrier sensing (PCS) based on tuning the PCS threshold has been shown to be an effective mechanism for improving aggregate network throughput. However, earlier work assumed a single link rate and a common PCS threshold for the entire network, as appropriate for a regular 2-D lattice grid of nodes with constant link (1-hop) distances. In an ad-hoc network topology, the 1-hop link distances vary significantly and a single PCS threshold is no longer suitable. Because IEEE 802.11 a/b/g networks provide multiple data rates over any link, joint tuning of the link rate and PCS threshold is thus desirable for achieving optimal aggregate throughput for ad-hoc networks. In this work, we first propose a simple yet effective principle for the above optimization. Next, we use the intuition offered by these formulations to suggest run-time adaptive solutions in OPNET simulations. We restrict ourselves to 1-dimensional random linear networks primarily to corroborate analysis with simulations and defer results with other topologies for future work