The document discusses energy-efficient routing protocols for wireless sensor networks (WSNs), focusing on the Equalized Cluster Head Election Routing Protocol (Echerp) and Power-Efficient Gathering in Sensor Information Systems with Double Cluster Head (Pdch). Both protocols aim to optimize energy consumption and extend network lifetime by employing hierarchical routing strategies and efficient cluster head selection methods. Simulation results indicate that Pdch outperforms Echerp in energy efficiency, control overhead, delay, and throughput.