802154

IEEE 802.15.4, commonly referred to as 802.15.4, is a standard developed by the IEEE for low-rate wireless personal area networks (LR-WPANs). It defines the physical and medium access control (MAC) layers to enable simple, low-cost, low-power wireless connectivity for devices with limited resources. The protocol stack provides a minimal yet robust foundation for short-range communication suitable for sensor networks, control applications, and Internet of Things deployments.

The standard specifies multiple physical layer options in unlicensed bands. In the 2.4 GHz ISM band, it supports a data rate of 250 kbps. In regional sub-GHz bands, 868 MHz (Europe) offers 20 kbps, while 915 MHz (North America) offers 40 kbps. The PHYs are designed to balance power consumption, range, and throughput according to application needs, with sub-GHz variants generally offering longer range at lower data rates.

MAC layer features include carrier sensing with collision avoidance, beacon-enabled and non-beacon networks, and a flexible topology model. Networks can be organized as star, tree, or mesh configurations with a PAN (personal area network) coordinator managing the network. Devices are categorized as full-function devices (FFD) or reduced-function devices (RFD). Security is provided through AES-128 encryption, with mechanisms for data integrity and authentication at the MAC layer.

IEEE 802.15.4 serves as the substrate for higher-layer protocols and standards such as Zigbee, Thread, and 6LoWPAN, enabling interoperable IoT ecosystems. It is widely used in home automation, industrial sensing, and other low-power wireless applications, where long battery life and modest data rates are prioritized.