Field Guide · protocol

Also known as: Zigbee, IEEE 802.15.4, 802.15.4, LR-WPAN

Zigbee is a low-power, low-data-rate mesh-networking standard for IoT and home automation, built on the IEEE 802.15.4 physical and MAC layers. The 2.4 GHz 802.15.4 radio uses offset-QPSK with direct-sequence spread spectrum across 16 channels.1 Zigbee adds the network, security, and application layers on top; the same 802.15.4 PHY also underpins Thread and 6LoWPAN.

coord R R R E R E E coordinator → routers (R) → end devices (E), packets relayed node to node
Zigbee forms a self-healing mesh: a coordinator and routers relay packets to battery end devices, extending range beyond any single hop.

Overview

At the radio level, the popular 2.4 GHz 802.15.4 PHY sends 250 kbit/s using offset QPSK: data symbols select one of 16 pseudo-random chip sequences, spread by DSSS so the signal tolerates interference and multipath. There are 16 channels spaced 5 MHz apart. Sub-GHz variants (868 MHz in Europe, 902–928 MHz in North America) use BPSK or OQPSK at lower rates for better range. On top of this radio, Zigbee layers a mesh network in which routers relay packets, letting battery-powered end devices reach a distant coordinator through intermediate hops.

Technical characteristics

Property Value
PHY standard IEEE 802.15.4
Bands 2.4 GHz (global), 868/915 MHz (regional)
Channels 16 × 5 MHz at 2.4 GHz
Modulation OQPSK with DSSS
Chip rate 2 Mchip/s → 250 kbit/s
Topology Star, tree, mesh
Range ~10–100 m per hop

Zigbee itself standardises “application profiles” (lighting, sensors, energy) so devices from different vendors interoperate. The mesh routing is what distinguishes it from simple point-to-point links.

History

IEEE 802.15.4 was first published in 2003. The Zigbee Alliance — now the Connectivity Standards Alliance — released Zigbee 1.0 in 2004 and later unified profiles under “Zigbee 3.0”. The same alliance now stewards Matter, which can bridge Zigbee networks.

Deployment

Zigbee is widespread in smart lighting, door and motion sensors, thermostats, and utility metering. It competes with Z-Wave, Thread, and proprietary sub-GHz systems; many smart-home hubs speak several of these at once.

Decoding it with GopherTrunk

GopherTrunk does not decode Zigbee or 802.15.4. Its DSSS OQPSK physical layer, mesh routing, and application-layer security are outside GopherTrunk’s land-mobile and aeronautical decode chain; dedicated 802.15.4 sniffers handle this traffic. GopherTrunk treats it purely as 2.4 GHz (or sub-GHz) background activity.

Sources

  1. IEEE 802.15.4 — Wikipedia, on the low-rate WPAN physical layer, its OQPSK/DSSS 2.4 GHz radio, channels, and sub-GHz variants; and Zigbee for the mesh networking layers. ↩

See also