802 15-4 tutorial
TRANSCRIPT
IEEE 802.15.4and Zigbee Overview
Topics
• 802.15.4• ZigBee• Competing Technologies• Products• Some Motorola Projects
Slide 2
• Home Networking
• Automotive Networks
• Industrial Networks
• Interactive Toys
• Remote Metering
IEEE 802.15.4 Applications Space
Slide 3
Some needs in the sensor networks
Thousands of sensors in a small space Wireless
but sensors are frequently stand alone Low Power
and sensors are frequently isolated Moderate Range.
Some of the challenges facing the standards committee
Slide 4 Joe Dvorak, Motorola 9/27/05
802.15.4 General CharacteristicsData rates of 250 kb/s, 40 kb/s and 20 kb/s.
Star or Peer-to-Peer operation.
Support for low latency devices.
Fully handshaked protocol for transfer reliability.
Low power consumption.
Frequency Bands of Operation
16 channels in the 2.4GHz ISM* band
10 channels in the 915MHz ISM band
1 channel in the European 868MHz band.
* ISM: Industrial, Scientific, Medical
Slide 5 Joe Dvorak, Motorola 9/27/05
IEEE 802.15.4 MAC
Applications
IEEE 802.15.4
2400 MHz
PHY
IEEE 802.15.4
868/915 MHz
PHY
802.15.4 / ZigBee Architecture
ZigBee
• Packet generation• Packet reception• Data transparency• Power Management
Slide 6 Joe Dvorak, Motorola 9/27/05
IEEE 802.15.4 PHY OverviewOperating Frequency Bands
868MHz / 915MHz PHY
2.4 GHz
868.3 MHz
Channel 0 Channels 1-10
Channels 11-26
2.4835 GHz
928 MHz902 MHz
5 MHz
2 MHz
2.4 GHz PHY
Slide 7 Joe Dvorak, Motorola 9/27/05
IEEE 802.15.4 PHY OverviewPacket Structure
PreambleStart ofPacket
Delimiter
PHYHeader
PHY ServiceData Unit (PSDU)
PHY Packet Fields• Preamble (32 bits) – synchronization • Start of Packet Delimiter (8 bits)• PHY Header (8 bits) – PSDU length• PSDU (0 to 1016 bits) – Data field
6 Octets 0-127 Octets
Slide 8 Joe Dvorak, Motorola 9/27/05
802.15.4 Architecture
IEEE 802.15.4 MAC
Applications
IEEE 802.15.4
2400 MHz
PHY
IEEE 802.15.4
868/915 MHz
PHY
• Channel acquisition• Contention mgt• NIC address• Error Correction
ZigBee
Slide 9 Joe Dvorak, Motorola 9/27/05
Extremely low cost
Ease of implementation
Reliable data transfer
Short range operation
• Very low power consumption
Simple but flexible protocol
IEEE 802.15.4 MAC OverviewDesign Drivers
Slide 10 Joe Dvorak, Motorola 9/27/05
IEEE 802.15.4 MAC OverviewTypical Network Topologies
Slide 11 Joe Dvorak, Motorola 9/27/05
• Full function device (FFD)– Any topology– Network coordinator capable– Talks to any other device
• Reduced function device (RFD)– Limited to star topology– Cannot become a network coordinator– Talks only to a network coordinator– Very simple implementation
IEEE 802.15.4 MAC OverviewDevice Classes
Slide 12 Joe Dvorak, Motorola 9/27/05
Full function device
Reduced function device
Communications flow
Master/slave
PANCoordinator
IEEE 802.15.4 MAC OverviewStar Topology
Slide 13 Joe Dvorak, Motorola 9/27/05
Full function device Communications flow
Point to point Cluster tree
IEEE 802.15.4 MAC OverviewPeer-Peer Topology
Slide 14 Joe Dvorak, Motorola 9/27/05
Full function device
Reduced function device
Communications flow
Clustered stars - for example,cluster nodes exist between roomsof a hotel and each room has a star network for control.
IEEE 802.15.4 MAC OverviewCombined Topology
Slide 15 Joe Dvorak, Motorola 9/27/05
IEEE 802.15.4 MAC OverviewGeneral Frame Structure
Payload
PH
Y L
ayer
MA
CLa
yer
MAC Header(MHR)
MAC Footer(MFR)
MAC Protocol Data Unit (MPDU)
MAC Service Data Unit(MSDU)
PHY Header(PHR)
Synch. Header(SHR)
PHY Service Data Unit (PSDU)
4 Types of MAC Frames:
• Data Frame
• Beacon Frame
• Acknowledgment Frame
• MAC Command Frame
Slide 16 Joe Dvorak, Motorola 9/27/05
• Periodic data– Application defined rate (e.g. sensors)
• Intermittent data– Application/external stimulus defined rate (e.g.
light switch)
• Repetitive low latency data– Allocation of time slots
IEEE 802.15.4 MAC OverviewTraffic Types
Slide 17 Joe Dvorak, Motorola 9/27/05
802.15.4 Architecture
IEEE 802.15.4 MAC
Applications
IEEE 802.15.4
2400 MHz
PHY
IEEE 802.15.4
868/915 MHz
PHY
• Network Routing• Address translation• Packet Segmentation
• Profiles
ZigBee
Slide 18 Joe Dvorak, Motorola 9/27/05
ZigBee Stack Architecture
Slide 19 Joe Dvorak, Motorola 9/27/05
Typical ZigBee-Enabled Device Design
Typical design consist of RF IC and 8-bit microprocessor with peripherals connected to an application
Slide 20 Joe Dvorak, Motorola 9/27/05
Wireless Technology Comparison Chart
356 A
34KB /14KB
Slide 21 Joe Dvorak, Motorola 9/27/05