Backward Token-Based Routing Framework for Hierarchical Tree Construction and Collision-Controlled Transmission in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) require efficient routing mechanisms to ensure reliable data delivery while minimizing energy consumption and communication delay in resource-constrained environments. Conventional methods, including contention-based transmission schemes, often suffer from packet collisions, retransmissions, and increased latency as network density mounts. To combat these challenges, this paper proposes a Backward Token-Based Routing Framework (BTBRF) that allows a sink-initiated reverse-direction token propagation for hierarchical routing tree construction and controlled transmission scheduling in multi-hop WSN structures. In the proposed approach, backward tokens are generated at the sink node and establish parent–child relationships using hop count, path cost, and residual energy metrics. This ensures loop-free topology formation and regulated channel access. Hence, only authorized nodes participate in communication at a given time. The performance of the proposed framework was evaluated using the QualNet network simulator by varying node densities from 20 to 100 nodes. Simulation results demonstrate that the proposed method improves packet delivery ratio and throughput while reducing end-to-end delay and overall energy consumption compared with conventional single-token communication methods.