A Multi-Hop Cluster Routing Algorithm for Wireless Sensor Networks Targeting Narrow Space Monitoring

Wireless sensor networks (WSNs) are recognized as a promising enabling technology for health monitoring of elongated infrastructures such as bridges, tunnels and railways. However, the significant distribution span of WSN nodes within narrow spaces requires monitoring data to be transmitted to the base station via multi-hop routing, which poses higher demands on network energy efficiency and lifespan. This paper proposes a Multi-hop Cluster Routing Algorithm based on an Improved Sparrow Search Algorithm (ISSAMC) aimed at optimizing the optimal multi-hop path from cluster heads (CHs) to the base station, thereby extending the stability period and overall lifespan of WSNs in narrow spaces. The ISSAMC first employs a non-uniform clustering mechanism, taking into account the residual energy of nodes and the distance to the base station, to generate a CH distribution that aligns with the topological characteristics of the narrow structure. Next, a multi-objective fitness function is constructed to simultaneously minimize the total energy consumption of the CHs and the variance in energy consumption, along with a dynamic weight adjustment strategy to adapt to the time-varying characteristics of the network state. Finally, multi-hop path optimization is performed using an improved SSA that incorporates strategies such as population initialization based on Sobol sequences, discrete encoding and decoding mechanisms, and crossover techniques, resulting in high-quality multi-hop paths. Simulation results show that under the unified ideal simulation benchmark, compared with MH-LEACH, GAECH, BEBMCR and EBPSO algorithms, ISSAMC improves the network stability period by 231%, 94%, 60% and 49.5%, respectively, and extends the overall network lifetime by 55%, 31%, 25.5% and 24%, respectively.