Intra-cluster tone-based contention resolution mechanism for wireless sensor networks

This paper presents an energy-efficient technique for resolving intra-cluster contentions in cluster-based wireless sensor networks. The proposed technique, bit map - binary countdown (BM-BCD), provides collision-free medium access by exchanging short signal tones between the head node and member nodes of the cluster. The BM-BCD improves existing tone-based contention resolution schemes in the following two aspects. Firstly, BM-BCD overcomes the hidden terminal problem by actively involving head node into the contention resolution process. Secondly, BM-BCD introduces a novel group-splitting algorithm which improves energy efficiency of member nodes by spreading the contention resolution over all available elimination rounds. The paper also introduces a simple intra-cluster MAC protocol, named STAR-TONE, which incorporates the proposed BM-BCD, and provides an analytical model for dimensioning main protocol parameters. Our analysis, verified by simulations, demonstrates that BM-BCD reduces the power consumption during contention for up to 44.5% compared to the baseline countdown protocol under bursty traffic conditions. (C) 2016 Elsevier Ltd. All rights reserved.