Research on Multichannel Protocols for Wireless Sensor Networks (WSNs) focuses on improving communication efficiency, reducing interference, and enhancing network throughput by utilizing multiple frequency channels simultaneously. These protocols aim to minimize packet collisions and delay by intelligently assigning channels based on node density, traffic load, and link quality. Recent designs incorporate clustering-based mechanisms and dynamic channel allocation to balance energy consumption across nodes while maintaining connectivity. Machine learning and decision-based models such as the Analytical Hierarchy Process (AHP) are being used to optimize channel selection and switching strategies. Hybrid MAC-layer protocols integrate time and frequency scheduling to achieve low latency and high reliability in dense networks. Overall, multichannel communication techniques enhance scalability, robustness, and energy efficiency, making them vital for next-generation IoT-driven and large-scale WSN deployments.