ZigBee – Tutorial 2

Shashank Tadakamadla

Summary

• Introduction

• Architecture

• Network Topology

Introduction – Objective

Main objectives of ZigBee network are:

• Ease of installation• Reliable data transfer• Short range operation• Extremely low cost• Reasonable battery life• Simple and flexible protocol

Introduction - Characteristics• Over the air data rates of 250Kbps, 100Kbps, 40Kbps & 20Kbps.• Star or peer-to-peer operation• Allocated 16 bit short or 64 bit extended addresses• Optional allocation of Guaranteed Time Slots (GTS)• Carrier sense multiple access with collision avoidance (CSMA-CA)

channel access• Fully acknowledged protocol for transfer reliability• Low power consumption• Energy detection (ED)• Link quality indication (LQI)• 16 channels in the 2450 MHz band, 30 channels in the 915 MHz

band, and 3 channels in the 868 MHz band

Architecture - Components

FFD RFD

PAN Coordinator Coordinator Device Device

Components Of ZigBee Network

Architecture – FFD

• FFD or Full Functional Device

• This device can function either as a PAN coordinator or coordinator or device.

• Can communicate with any devices in a WPAN.

Architecture – RFD

• RFD or Reduced Functional Device

• Can communicate only with PAN coordinator

• These devices are used where only minimal resources and memory are required.

Architecture – PAN Coordinator

• PAN Coordinator should be an FFD• Only one in a network• Initiates network• Stores information about the network• All devices communicate with the PAN

coordinator• Routing functionality• Bridge to other networks

Architecture – Coordinator

• Coordinator should be an FFD

• Otherwise called as an Router

• Optional component

• Routes between nodes

• Extends network coverage

• Manages local address allocation / deallocation

Architecture – Device

• Device can be an FFD or RFD based on application

• Optimized for low power consumption

• Cheapest device type

• Communicates only with the coordinator

Network Topology - Types

PAN coordinator / FFD

RFD

STAR Network

Coordinator / FFD

PEER-TO-PEER Network