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ZIGBEE® The wireless standard for tomorrow’s smart grid

PRESENTED BY:-SUMIT KUMAR SAHUO701227155COMPUTER SCIENCE & ENGINEERINGCS1(A)

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1)INTRODUCTION2)CHARCTERISTICS3)DEVICE TYPES4)NETWORK MODEL5)FRAME STRUCTURE6)SUPERFRAME STRUCTURE7)ARCHITECTURE8)ROLE OF SEVERAL LAYERS9)ADVANTAGES10)DISADVANTAGES11)APPLICATIONS12)CONCLUSION

SCOPE OF THE SEMINAR

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ZIGBEE IS BUILT ON TOP OF THE IEEE 802.15.4 LOW POWER NETWORKING STANDARD.  

THE 802.15.4 STANDARD IS A SIMPLE PACKET DATA PROTOCOL FOR LIGHTWEIGHT WIRELESS NETWORKS.

ZIGBEE ADDS KEY FUNCTIONALITY ON TOP OF THE CORE NETWORKING SUPPORT PROVIDED BY THE IEEE 802.15.4 STANDARD INCLUDING SUPPORT FOR PEER TO PEER AND MESH NETWORKING.

WHAT IS ZIGBEE?????

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ZIGBEE/IEEE 802.15.4 – GENERAL CHARACTERISTICS

•Dual PHY (2.4GHz and 868/915 MHz)•Data rates of 250 kbps (@2.4 GHz), 40 kbps (@ 915 MHz), and 20 kbps (@868 MHz)•Optimized for low duty-cycle applications (<0.1%)•CSMA-CA channel access•Yields high throughput and low latency for low duty cycle devices like sensors and controls•Low power (battery life multi-month to years)•Multiple topologies: star, peer-to-peer, mesh•Addressing space of up to:18,450,000,000,000,000,000 devices (64 bit IEEE address)65,535 networks•Optional guaranteed time slot for applications requiring low latency•Fully hand-shaked protocol for transfer reliability•Range: 50m typical (5-500m based on environment)

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DEVICE TYPES

To allow vendors to supply the lowest possible cost devices the IEEE standard defines two types of devices: full function devices and reduced function devices

Full function device (FFD)Can function in any topologyCapable of being the Network coordinator Capable of being a coordinatorCan talk to any other device Reduced function device (RFD)Limited to star topologyCannot become a network coordinatorTalks only to a network coordinatorVery simple implementation 

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Star Topology

PANCoordinator

Full function device

Communications flow

Peer to Peer topology

Cluster Tree Topology

Reduced Function Device

Communication flow

Full functional device

NETWORK CONSIDERATIONS

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FRAME STRUCTURE The IEEE 802.15.4 MAC defines four frame structures:A beacon frame, used by a coordinator to transmit beacons.A data frame, used for all transfers of data.An acknowledgment frame, used for confirming successful frame reception.A MAC command frame, used for handling all MAC peer entity control transfers. The data frame is illustrated below:  

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SUPER FRAME STRUCTURE

oThe super frame is bounded by network beacons, is sent by the coordinatoroThe beacon frame is transmitted in the first slot of each super frame.oAny device wishing to communicate during the contention access period (CAP) between two beacons shall compete with other devices using a slotted CSMA-CA mechanism.

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For low latency applications GUARANTEED TIME SLOTS (GTSs)are presentIt comprises of CONTENTION FREE PERIOD(CFP)The PAN coordinator may allocate up to seven of these GTSs and a GTS may occupy more than one slot perioda sufficient portion of the CAP shall remain for contention based access of other networked devices or new devices wishing to join the network . All contention based transactions shall be complete before the CFP begins. Also each device transmitting in a GTS shall ensure that its transaction is complete before the time of the next GTS or the end of the CFP.

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ZIGBEE ARCHITECTURE

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A. PHYSICAL LAYER

B. MAC LAYER

C. NETWORK LAYER

D. APPLICATION LAYER

E. SECURITY LAYER

ARCHITECTURE contains the following layers

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MAC DATA SERVICE DIAGRAMS

BEACON NETWORK

NON BEACON NETWORK

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MAC PRIMITIVES  MAC Data ServiceMCPS-DATA – exchange data packets between MAC and PHYMCPS-PURGE – purge an MSDU from the transaction queue  MAC Management ServiceMLME-ASSOCIATE/DISASSOCIATE – network associationMLME-SYNC / SYNC-LOSS - device synchronizationMLME-SCAN - scan radio channelsMLME- COMM-STATUS – communication statusMLME-GET / -SET– retrieve/set MAC PIB parametersMLME-START / BEACON-NOTIFY – beacon managementMLME-POLL - beaconless synchronizationMLME-GTS - GTS managementMLME-RESET – request for MLME to perform resetMLME-ORPHAN - orphan device managementMLME-RX-ENABLE - enabling/disabling of radio system 

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ROLE OF NETWORK & APPLICATION LAYER

The IEEE 802.15.4 PHY and MAC along with ZigBee’s

Network and Application Support Layer provide:

•Extremely low cost

•Ease of implementation

•Reliable data transfer

•Short range operation

•Very low power consumption

•Appropriate levels of security

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RESPONSIBILITIES OF ZIGBEE NWK LAYER

•Starting a network

•Joining and leaving a network

•Configuring a new device

•Addressing

•Synchronization within a network

•Security

•Routing

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RESPONSIBILITY OF APPLICATION LAYER

The ZigBee application layer consists of the APS sub-layerthe ZDO the manufacturer-defined application objects.

The responsibilities of the APS sub-layer include maintaining tables for binding & discovery

The responsibilities of the ZDO include defining the role of the device within the network

The manufacturer-defined application objects implement the actual applications according to the ZigBee-defined application descriptions 

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SECURITY LAYER PERSPECTIVESZigBee uses MAC layer security to secure MAC command, beacon, and acknowledgement framesmulti-hop messaging ZigBee relies upon upper layers (such as the NWK layer) for securityThe MAC layer uses the Advanced Encryption Standard (AES) as its core cryptographic algorithm. The MAC layer security suites are based on three modes of operation. Encryption at the MAC layer is done using AES in Counter (CTR) mode and integrity is done using AES in Cipher Block Chaining (CBC- MAC) mode [16]. A combination of encryption and integrity is done using a mixture of CTR and CBC- MAC modes called the CCM mode.

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Standard Bandwidth Power Consumption

Protocol Stack Size

Stronghold Applications

Wi-Fi Up to 54Mbps 400+mA TX, standby 20mA

100+KB High data rate Internet browsing, PC networking, file transfers

Bluetooth 1Mbps 40mA TX, standby 0.2mA

~100+KB Interoperability, cable replacement

Wireless USB, handset, headset

ZigBee 250kbps 30mA TX, standby 3#&956;A

4+32KB Long battery life, low cost

Remote control, battery-operated products, sensors

ADVANTAGES OF ZIGBEE OVER OTHER NETWORK

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ADVANTAGES OF ZIGBEE NETWORK

Cost savings – Installation without physical wiring will avoid the $50 to $100 cost per foot of wire (includes labor costs). In addition, robust, self configuring mesh networks will save on maintenance costs.Rapid commissioning – Installation and provisioning of devices can occur rapidly and without significant costs or physical construction.Flexibility – Placement of sensors in optimal locations allows a network to be adaptable and reconfigurable.In addition, placing sensors on all parts of an operation will allow applications never before considered for manufacturing, warehouses, and operational facilities.Reliability – Monitoring a large number of inexpensive sensors will offer improved control information, and capabilities to prevent failure and avoid system downtime.

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DISADVANTAGES OF ZIGBEE NETWORK

Large code size / memory footprint (limits memory available for Application Layer).Slow performance on 8-bit microprocessors.Large RAM requirements for Repeaters/Routers.Requires a lot of expertise to create the Application Layer.Requires a lot to expertise to configure and manage the network.Throughput is limited.Power consumption is relatively high.It supports high-level protocols that facilitate interoperability.These are currently in a primitive state and don't fit the application well.It is an open standard.Products require certification to ensure compatibility.It can take more time to develop and test a new solution.

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  ZIGBEE APPLICATIONS

• Periodic data – usually defined by the application such as a

wireless sensor or meter. Data typically is handled using a

beaconing system whereby the sensor wakes up at a set time

and checks for the beacon, exchanges data, and goes to sleep.

• Intermittent data – either application or external stimulus

defined such as a wireless light switch. Data can be handled in a

beaconless system or disconnected. In disconnected operation,

the device will only attach to the network when communications

is required, saving significant energy.

• Repetitive low latency data – uses time slot allocations

such as a security system

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CONCLUSION

ZigBee's 32 KB is about one-third of the stack size necessary in other wireless technologies

Unwired applications are highly sought after in many networks

The IEEE 802.15.4–based ZigBee is designed for remote controls and sensors, which are very many in number, but need only small data packets and , mainly, extremely low power consumption for(long) life.

ZigBee technology is designed to best suit these applications, for the reason that it enables reduced costs of development and very fast market adoption.

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THANK U

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