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How ZigBee/802.15.4 Protocol SimplifiesWireless M2M CommunicationsJune 4th, 2008
Cyril ZaraderProduct Marketing Manager EMEA – Wireless Connectivity
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Topics
IEEE 802.15.4 : Made for Reliable Low PowerWireless Networking
ZigBee : Made for Simple Deployment of WirelessM2M Communications
ZigBee Compared to Other Industrial WirelessProtocols
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Selection of Wireless Technologies
Range
Peak
Dat
a R
ate
Closer Farther
Slow
erFa
ster
UWBWireless DataApplications
WirelessVideo
Applications
IrDA
802.11g
802.11b
802.11a
2.5G/3G
Bluetooth™ZigBee™
DataTransfer
WirelessNetworking
Wi-Fi®
Cellular
NFC/RFID
802.15.4
802.15.1
802.15.3
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Wireless Networking Technologies
N/ALonMark®
InteroperabiltyAssociation
Wi-FiTM
Alliance
UWBTM Forum& WiMediaTM
AllianceBluetooth® SIGZigBeeTM AllianceIndustry
Groups
P2P, Star,Mesh
Medium-dependentStarStarStarMesh, Star, TreeTopology
100-1,00032,00032128865,000Nodes
Alkaline(Months-Years)
N/ARechargeable(Hours)
Rechargeable(Hours-Days)
Rechargeable(Days-Weeks)
Alkaline(Months-Years)
BatteryOperation(Life)
Very Low-LowWiredHighLowLowVery LowPower
10-70 mMediumDependent10-100 m4-20 m10 m10-70 mRange
10-250 Kbps15 Kbps-10 Mbps11-105 Mbps110Mbps-
1.6Gbps723 Kbps250 KbpsData Rate
RFFrequency
Standard
868/915 MHz2.4 GHz
IEEE® 802.15.4
ZigBeeTM
433/868/900MHz
2.4 GHz
N/A (wiredtechnology)
2.4 GHz5.8 GHz
3.1-10.6 GHz(U.S.)2.4 GHz
ProprietaryEIA 709.1,2,3IEEE® 802.11a, b, g (n tobe ratified)
IEEE®
802.15.3a(to be ratified)
IEEE®
802.15.1
ProprietaryLonWorks®Wi-FiTMUWBTMBluetooth®
Key strengths Key weaknesses
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IEEE 802.15.4 : Made forReliable Low PowerWireless Networking
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Matching Applications to Wireless Technologies
Imagery and Audio• High-quality, live video and audio
� WUSB, Wi-Fi, WiMax
• Low to mid-quality, live or still images and low- to moderate-qualityaudio� WUSB, Wi-Fi, Bluetooth, 802.15.4, Cellular
Low- to moderate-rate communications and control systems• 802.15.4, Wi-Fi, Cellular
Extreme-battery-life sensor and control systems• 802.15.4• Months to years to decades, depending on the application and duty
cycle
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Data Collection and Delivery Cost
Wireless cuts the data wire and saves the cost of installation androuting of specialized cables
� Running permanent wiring to a device can cost from €10 to €100 per meterin commercial facilities
� For homes, retrofitting control and monitoring cabling costs about €20 to €40per square meter of floor area covered
• Needs a source of permanent power or must be very battery-efficient
Removing the data wires AND removing the connection to permanentpower is the goal
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Data Rate Matters
Typical Operating environments with dozens to hundreds ofmachines:
• Say what you need to say quickly, then get off the air� A busy channel is an unreliable channel� Keep the channel availability high to reduce retries, latency and improve
quality of service� Higher data rates make message transmission faster and channel
occupancy lower� Faster communications and longer sleep times can mean less energy
consumption
• BUT, transmitting faster than you need to can lead to� Increased transceiver cost� Tighter requirements on timing� Increased receiver complexity� Increased energy consumption
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IEEE802.15.4 PHY Characteristics
Simple packet data protocolfor lightweight wirelessnetworks
• Released in May 2003• Primary channel access is via
Carrier Sense Multiple Access withcollision avoidance
• Message acknowledgement and anoptional beacon structure
• Multi-level security• Works well for
� Long battery life, selectable latencyfor controllers, sensors, remotemonitoring and portable electronics
• Configured for maximum batterylife, has the potential to last as longas the shelf life of most batteries
ZigBee relies upon IEEE 802.15.4,which has excellent performance in
low SNR environments
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IEEE 802 Standards are Designed to Coexist
Frequency Domain• Multiple, non-aligned channels• Spread spectrum for added
robustness• Phase-Shift keying and direct-
sequence spread spectrum
Time Domain• Both 802.11 and 802.15.4 radios
“listen before talking” to avoidcollisions
Protocol Robustness• ACK required for successful data
transfer• No ACK, station tries again when
channel clears
802.11 packets
802.15.4 packets t
Retries
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Low Channel Occupancy – Critical to Reliability
Typical scenario with 100 to 1000 devices
• Constant monitoring of the environment requires regularcommunications
• Even once every few minutes for all devices, this can mean hundreds ofmessages per minute
• 2.4GHz ZigBee data rates are 250kbps• Packets generally under 2ms in duration, and two-way
acknowledgement adds about 600us per message• In practical environments and usage, channel occupancy ~1%• Even with multiple nearby networks, the channel is mostly empty!• The channel is available when the network needs it
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Mesh Networking Improves Robustness
ZigBee CoordinatorZigBee RouterZigBee End DeviceZigBee Device Associations
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802.15.4 Summary
802.15.4 is designed to provide a solid foundation for sensing and control applications
Providing a global standard• 2.4 GHz provides global support for products• Additional sub 1 GHz work adding options for Asia, Europe, and US
Technology is real and available• Mass production since 2003• 7-10 Million units shipped in 2007
Provides a variety of sources for chipsets and network stacks• Eliminates the concerns with a single source• Provides lower cost and increased competition
Provides for key technology advantages for monitoring and control• Optimized for low duty cycle applications• Longer battery life (months to years)
Proving to be robust in the presence of interference• Channel Alignment – ideal for co-existence with other 2.4 GHz technologies• Clear Channel Assessment – improves collision avoidance• Short burst transmission
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ZigBee : Made for SimpleDeployment of WirelessM2M Communications
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ZigBeeZigBeeTMTM
Was created by the ZigBee Alliance
Is based on the IEEE 802.15.4 Standard
Targets wireless control and monitoring applications
Uses Mesh networking to cover large areas with short-range low-power radios
www.zigbee.org
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IEEE 802.15.4 & ZigBee Alliance
PHY LAYER868MHz / 915MHz / 2.4GHz
MAC LAYER
SECURITY LAYER32- / 64- / 128-bit encryption
APPLICATION FRAMEWORK
APPLICATION/PROFILES
IEEE802.15.4
ZigBeeAlliancePlatform
ApplicationZigBee Platform StackSilicon
ZigBee or OEM
NETWORK LAYERStar / Mesh / Cluster-Tree
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PAN coordinator (PANC)
Full Function Device (FFD,Router)
Reduced Function Device (RFD)
Star
Mesh
Cluster Tree
Network Topology Models
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ZigBee Recap
ZigBee relies upon the robust IEEE 802.15.4 PHY/MAC to provide reliabledata transfer in noisy, interference-rich environments
• Message acknowledgement and an optional beacon structure• Multi-level security
Ideal For• Low data rate monitoring and control applications that require a robust network
� Low latency, infrequent, low data rate and small packet data• Large area coverage
� Using the mesh networks that support 1000 of devices• Ultra low power monitoring applications that operate for years on inexpensive
alkaline batteriesNot Ideal For
• Applications requiring long range without using routers• Mobile applications
� Being addressed in future revision• Streaming data
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ZigBee Vs. Market Requirements
Cellular
Nodes Density
Ease of use
Radio Friendly
Nodes Density
Device Mobility
Network Scalability
Reliable Communications
Lightweight
ZigBeeUWBWiFiBluetoothMarket Requirements
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Industrial WirelessProtocols Overview
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WirelessHART™ Specification Technical Overview
Based on 802.15.4 – 2006• Specification completed in 2007
Focuses on features for reliabilityand co-existence
• Adds channel hopping� Uses TDMA with a fixed 10ms time slot� Black listing of bad channels� Provides for sleeping routers
• Higher default transmit power� +10dBm
• Mesh Network Topology� Based on DUST Networks TSMP (Time
Synchronized Mesh Protocol� Provides flexible network organization� Provides redundant paths� Self organizing and self healing
• Dynamic bandwidth allocation� Fixed bandwidth for prioritized data and
commands• Supports AES-128 ciphers and key support
Supports common HART devices• Wireless Field devices• Bridges, Gateways and Access Points
provide seamless access throughout thenetwork
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ISA100.11a Technical Overview
Reliable low-power communication• Based on IEEE 802.15.4 radios in the 2.4
GHz ISM band• Time-synchronized channel-hopping to
sidestep RF interference and minimize powerconsumption
� Allows for FFD devices such as routers to sleepAdaptive Mesh Network
• Supports mesh, star-mesh and startopologies
• Self-organizing intelligence simplifiesinstallation and automatically adapts tochanging conditions
Robust Security• All messages protected with AES128 block
cipher• Secure communication and device
authentication enabled by exchange of secretkeys and unique device identifiers
Unified Application Interface• Provides an open and interoperable
application environment• Provides a common integration point for
multiple host systems
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802.15.4 Protocol Stack Positioning
Cost
Less Sensitive
Cost S
ensitiveC
ost is King
MarketConsumer Commercial Industrial
ISA SP100.11a
ZigBee® Protocol
WirelessHART™Specification
Synkro™Networking
Protocol
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Comparison Table by major features
IndustrialIndustrialConsumer andCommercialTarget Market
GoodBetter*BestBattery Life
Industrial ControlProcess ControlFactory Automation
Smart Energy,Building AutomationTarget Applications
YesYesYesCertification Program
YesYesNoMessage Priority (QOS)HighMediumLowCostYesYesProfileKey Exchange
AES128AES128AES128Encryption
BlacklistBlacklistPreferred channelChannel Blacklist / PreferredChannels
10ms10ms4msLatency
YesYesNoAddressed in FutureSpec
Sleeping Routers
FFDFFD, RFDFFD, RFDDevice TypeMeshMesh, TreeMesh, TreeTopology
HoppingHoppingAgility - 2007 SpecChannel Hopping/Agility200620062003802.15.4
WirelessHART™SpecificationSP100™ZigBee® ProtocolFeature
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Table with Pro/Cons
• More costly components required• TDMA mode only
• Deterministic• Immune to Multipath• Sleeping Routers• Existing wired devices in market
WirelessHART™Specification
• More costly components required• Object Structure in the Application Layersadds structure which might be viewed bydevelopers as too restrictive
• Deterministic• Immune to Multipath• Sleeping Routers• CSMA and TDMA tunable• Multiple Fieldbus support• IPv6 Support
SP100.11a
• Not cost effective for high volumeconsumer• Complex• Not “Industrial Grade”
• General market appeal• Lots of backing in Smart Energy space• Products in market today
ZigBee® Protocol
ConsProsTechnology
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Questions ?