ZigBee/IEEE 802.15.4

Sequence

• Background

• Gen Characteristics

• How it works– Tech

– Bandwidth/ energy consumption

• Architecture

• Comparison with other WPAN Standards

• Applications

Why ZigBee ?

– Wireless communication standards:• IEEE 802.11 a/b/g

• Bluetooth

• GSM

– What makes them unattractive for WSN:• Power hungry (need big batteries)

• Complexity (need lots of clock cycles and memory)

– New protocol for WSN:• 802.15.4 and Zigbee (ratified in Dec 14, 2004)

• Low Cost

• Low Power Consumption

• Scalability and Reliability

Origin Of Name ZigBee

• The technique that honey bees use to communicatenew-found food sources to other members of thecolony is referred to as the ZigBee Principle.

• Using this silent, but powerful communicationsystem, whereby the bee dances in a zig-zag pattern,she is able to share information such as the location,distance, and direction of a newly discovered foodsource to her fellow colony members. Instinctivelyimplementing the ZigBee Principle.

Within the broad organization of the Institute of Electrical andElectronics Engineers (IEEE), the 802 group is the section thatdeals with network operations and technologies. Group 15works more specifically with wireless networking, and TaskGroup 4 drafted the 802.15.4 standard for a low data ratewireless personal area network (WPAN).

The ZigBee standard is currently an ‘open’ standard only tothose that are a part of the ZigBee Alliance. For this reason,the ZigBee standard was not used to implement theapplication layer.

802.15.4 Standard (WPAN)

IEEE 802.15 working group

6

ZigBee General Characteristics

• Data rates of 20 kbps and up to 250 kbps

• Intended for 2.45 Ghz , 868 Mhz and 915 Mhz Band

• Data rates touch 250Kbps for 2.45Ghz ,40 Kbps 915Mhz and 20Kbps for 868Mhz band

• Star or Peer-to-Peer network topologies

• Support for Low Latency Devices

• CSMA-CA Channel Access

• Handshaking

• Low Power Usage consumption

• 3 Frequencies bands with 27 channels

• Extremely low duty-cycle (<0.1%)

Comparision Graph with Other Wireless Standards

Complexity, Power, Cost

Data rate

802.11a

802.11g802.11b

Bluetooth

802.15.4Zigbee

54Mbps11Mbps

720 kbps

250 kbps

Why NOT 802.11 ?The Cost of Throughput

• High data rates– up to 11Mbps for b and

– up to 54Mbps for g and a)

• Distance up to 300 feet, or more with special antennas

• High power consumption – Sources about 1800mA when transceiver is

operational.

ZigBee Aims Low

• Low data rate

• Low power consumption

• Small packet devices

What Does ZigBee Do?

• Designed for wireless controls and sensors

• Operates in Personal Area Networks (PAN’s) and device-to-device networks

• Connectivity between small packet devices

• Control of lights, switches, thermostats, appliances, etc.

How ZigBee Works

• Devices

– Zigbee Coordinator Node

– Zigbee Full Function Node

– Zigbee Reduced Function Node

• Modes of operation– Beacon

– Non-beacon

Device Types and Roles

• Zigbee Coordinator Node (ZCN):

• It is the root of the network tree

• Acts as a bridge to other networks.

• Stores Information about the Network

• There is only one ZCN for the complete Network

Device Types and Roles

• Zigbee Full Functional Device (FFD):• An Intermediate router in the Network

• Transmitting and Receiving data from other devices

• Needs less memory than Zigbee Coordinator Node

• Lesser Manufacturing cost

• Can operate on all topologies

Device Types and Roles

• Zigbee Reduced Function Device (FFD):• Also called the End Device

• Device capable of talking in the Network

• Can’t relay data from other devices

• Cheaper than FFD

• Lesser Manufacturing cost

• Talks only to the Network Coordinator

Device Types and Roles

• Beacon Mode :In beacon-enabled networks, the special network nodes calledZigBee Routers transmit periodic beacons to confirm theirpresence to other network nodes. Nodes may sleep betweenbeacons, thus lowering their duty cycle and extending theirbattery life.

• Non Beacon ModeIn non-beacon-enabled networks, an unslotted CSMA/CAchannel access mechanism is used. In this type of network,ZigBee Routers typically have their receivers continuouslyactive, requiring a more robust power supply.

Modes of Operation

Modes of Operation

Modes of Operation

Zigbee Network Topologies

Zigbee Network Topologies

ZigBee Mesh Networking

ZigBee Mesh Networking

ZigBee Mesh Networking

ZigBee Mesh Networking

ZigBee Mesh Networking

Architecture

– “the software”

– Network, Security &

Application layers

– Brand management

IEEE 802.15.4

– “the hardware”

– Physical & Media Access

Control layers

PHY868MHz / 915MHz / 2.4GHz

MAC

NetworkStar / Mesh / Cluster-Tree

Security32- / 64- / 128-bit encryption

Application

API

ZigBeeAlliance

IEEE 802.15.4

Customer

Silicon Stack App

Architecture

Device Addressing

• All devices have IEEE addresses

• Short addresses can be allocated

• Addressing modes:

– Network + device identifier (star)

– Source/destination identifier (peer-peer)

– Source/destination cluster tree + device identifier (cluster tree)

ZigBee Network Addressing

–Every device has a unique 64 bit MAC address

–Upon association, every device receives a unique 16bit network address

–Only the 16 bit network address is used to routepackets within the network

Comparison with other Wireless Standards

Data Rate (Mbps)

ZigBee802.15.4

802.15.3802.15.3a802.15.3c

WPAN

WLAN

WMAN

WWAN

WiFi802.11

0.01 0.1 1 10 100 1000

Bluetooth802.15.1

IEEE 802.22

WiMaxIEEE 802.16

IEEE 802.20

Zigbee and Bluetooth

Feature(s) Bluetooth ZigBee

Power Profile days years

Complexity complex Simple

Nodes/Master 7 64000

Latency 10 seconds 30 ms – 1s

Range 10m 70m ~ 300m

Extendibility No Yes

Data Rate 1 Mbps 250 Kbps

Security 64bit, 128bit 128bit AES and

Application Layer

ZigBee Alliance

• IEEE 802.15.4 Working Group

– Defining lower layers of protocol stack: MAC and PHY

– Available today

• ZigBee Alliance

– 50+ companies: semiconductor mfrs, IP providers, OEMs, etc.

– Defining upper layers of protocol stack: from network to application, including application profiles

– Initial draft available mid 2003

SILICON

ZIGBEE STACK

APPLICATION Customer

IEEE

ZigBee Alliance

ZigBee Alliance

Applications

PERSONAL

HEALTH CARE

ZigBeeLOW DATA-RATE

RADIO DEVICES

HOME

AUTOMATION

CONSUMER

ELECTRONICS

PC &

PERIPHERALS

TOYS &

GAMES

INDUSTRIAL

&

COMMERCIAL

ZigBee Applications

• Wireless home security

• Remote thermostats for air conditioner

• Remote lighting, drape controller

• Call button for elderly and disabled

• Universal remote controller to TV and radio

• Wireless keyboard, mouse and game pads

• Wireless smoke, CO detectors

• Industrial and building automation and control (lighting, etc.)

ZigBee Applications

ZigBee Applications

Queries!. .U

Thank you!