DCW-CSMA/CA: Cross-Layer Design With Dynamic Contention Window Adaptation for Dense Wireless Sensor Networks

Linear Wireless Sensor Networks (LWSNs) are often deployed in unsupervised scenarios such as railways. However, dynamic environments are prone to signal fading and packet loss, resulting in increased transmission delay and decreased throughput. To address this problem, this paper proposes a parallel transmission DCW-CSMA/CA protocol based on the linear topology. The protocol designs a dynamic competition window adjustment algorithm based on node density to reduce multi-hop transmission delay. In addition, under the constraints of single-hop transmission and double-hop interference, DCW-CSMA/CA selects nodes with the highest residual energy in topology groups to perform concurrent data transmission, thereby enhancing network throughput. To ensure fair data transmission among nodes at different depths along multi-hop paths, this paper introduces a dual-queue fair scheduling mechanism. Simulation experiments conducted on the OMNeT++ platform demonstrate that the proposed DCW-CSMA/CA protocol achieves approximately 2.3 times higher throughput than traditional CSMA protocols and exhibits lower transmission latency than three comparison protocols, thus validating its efficiency and practicality in LWSNs.