CheatSheet - ZigBee

ZigBee Communication

• Type of WPAN (Wireless Personal Area Network), usefull for Low power, medium to long range, low data rate Mesh communication, for example sensor networks and building automation.
• Specification based on the IEEE 802.15.4 Protocol.
  • IEEE 802.15.4 Is responsible for defining the PHY and MAC layer. This means getting access to the channel and sending packet from point to point.
  • Zigbee defines the Network and APS layer as well as security.
• Uses the Zigbee PRO 2015 or newer network protocol
• Network topology: Routed, Self forming, Self healing, mesh
• Network size: Theoretical limit of 65,000 devices
• Data rate: 250 kbps
• Communication range: 300m line of sight OR 75 to 100m Indoors
• Network Device types
  • Coordinator: Forms the network, may be powered off after forming, is capable of routing
  • Router: AC powered device, maintains routing and neighbour tables, manages sleeping devices
  • End device: battery powered sleeping device. Polls parent router for any packets buffered. Depends on parent router to route its packets.
  • Zigbee Greep Power Device: Lowest energy consumption
• Packet payload - 129 bytes overall, 98 bytes application payload without encryption.

IEEE 802.15.4 (PHY and MAC)

• Spectrum used by ZigBee:

  

• Though the 802.15.4 defines many channels, ZigBee primarily uses the ones shown above in the ISM band.
• There are 16 channels of 2 MHz band width and 5 MHz band gap.

Network Architecture

• Network is defined by the Coordinator using the Extended PAN ID.
• Each device on the network has a extended MAC ID. During commissioning, the coordinator assigns a short address to the device as well.
• In the actual communication, the short PAN derived from extended PAN and the short address are used to conserve header space.
• Uses CSLKIP addressing procedure. In this, the network looks like a tree with the coordinator at root. However, once the network is formed, it’s a mesh network with any to any communication.
• Network formation:
  • Coordinator selects the Channel and the PAN ID. These values can be set manually as well
• Joining a network:

Detailed analysis

• CSKIP addressing
• Security
• Routing concepts
  • Routing tables
  • Route discovery
  • Route maintenance (Healing)