IEEE 802.15.4 is a technical standard that defines the physical and media access control layers for low-rate wireless personal area networks (LR-WPANs). It is designed for low-power, low-data-rate communication, making it suitable for applications like smart home devices, sensor networks, and industrial automation. This standard operates in various frequency bands, including 2.4 GHz, 915 MHz, and 868 MHz, allowing for flexible deployment in different regions. IEEE 802.15.4 serves as the foundation for higher-layer protocols, such as Zigbee and Thread, which enable more complex networking and application functionalities.