ZIGBEE

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• ZIGBEE
• Compared to
• BLUETOOTH

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Presentation Outline

• What ZigBee is
• What ZigBee does
• How ZigBee works
• Bluetooth.
• Differences and similarities between Zigbee and
  Bluetooth.
• how to make them coexist.

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What is ZigBee?

• ZigBee is a standard wireless network protocol
  designed for low data rate control networks.
• It is layered on top of the IEEE 802.15.4
  specification and provides a standard methodology
  for functions, including network formation,
  messaging and device discovery.
• for the unique needs of remote monitoring and
  control applications, including simplicity,
  reliability, low-cost and low-power.

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Zigbee characteristics

• 2.4GHz and 868/915 MHz
• The number of channels allotted to each
  frequency band is fixed at 16 channels in the
  2.45 GHz band, 10 channels in the 915 MHz band,
  and 1 channel in the 868 MHz band.
• Maximum data 250 kbps _at_2.4 GHz, 40 kbps _at_ 915
  MHz, and 20 kbps _at_868 MHz.
• Allocation of guaranteed time slots (GTSs).
• Carrier sense multiple access with collision
  avoidance (CSMA-CA) channel access Yields high
  throughput and low latency for low duty cycle
  devices like sensors and controls.
• Low power consumption with battery life ranging
  from months to years. Energy detection (ED).Link
  quality indication (LQI).
•  

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CHANNELS
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What Does ZigBee Do?

• Designed for wireless controls and sensors
• Operates in Personal Area Networks (PANs) and
  device-to-device networks
• Connectivity between small packet devices
• Control of lights, switches, thermostats,
  appliances, etc.

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ARCHITECTURE
ZigBee Application layer
ZigBee Network layer
802.15.4 MAC
802.15.4 PHY E
802.15.4 PHY
868/915 Mhz
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• Physical (PHY) layer
• The PHY service enables the transmission and
  reception of PHY protocol data units(PPDU) across
  the physical radio channel.The features of the
  IEEE 802.15.4 PHY physical layer are Activation
  and deactivation of the radio transceiver,
  energy detection (ED), Link quality
  indication (LQI), channel selection, clear
  channel assessment (CCA) and transmitting as well
  as receiving packets across the physical medium. 
• Media access control (MAC) layer
• The MAC service enables the transmission and
  reception of MAC protocol data units (MPDU)
  across the PHY data service. The features of MAC
  sub layer are beacon management, channel access,
  GTS management, frame validation, acknowledged
  framedelivery, association and disassociation.

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How ZigBee Works

• Topology
• Star
• Cluster Tree
• Mesh

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How ZigBee Works

• States of operation
• Active
• Sleep
• Devices
• Full Function Devices (FFDs)
• Reduced Function Devices (RFDs)

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STAR TOPOLOGY
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CLUSTER NETWORKS
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Zigbee mesh network
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• Research in ZigBee is being conducted in
  different fields
• Wireless and sensor networks.
• Wireless communications.
• Neuro-engineering.

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• ZIGBEE
• Coexistence with other standards
• Relatively wideband interference, such as that
  generated by IEEE 802.11b networks
• Impact of interference from Bluetooth (802.15.1)
  devices should be minimal.

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Bluetooth

• Bluetooth operates in the unlicensed 2.4
  gigahertz (GHz) to 2.4835 GHz .
• Bluetooth employs frequency hopping spread
  spectrum (FHSS) technology for all transmissions.
  
• FHSS reduces interference and transmission errors
  and provides a limited level of transmission
  security.

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Bluetooth architecture

• Bluetooth permits devices to establish either ad
  hoc or infrastructure networks.
• Ad hoc networks provide easy connection
  establishment between mobile devices in the same
  physical area (e.g., the same room) without the
  use of any infrastructure devices. A Bluetooth
  client is simply a device with a Bluetooth radio
  and software incorporating the Bluetooth protocol
  stack and interfaces.

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Bluetooth Ad Hoc Topology
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Bluetooth Networks (Multiple Scatternets)
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Coexistence components

• 1. Channel estimation
• 2. MAC layer protocol behavior
• 3. Channel selection
• 4. Modulation
• 5. Protocol collaboration

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• -gt Channel estimation-
• 1 .Received Signal Strength Indication
• 2. Carrier Sense
• 3. Packet Error Rate
• 4. Packet Acknowledgment

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• -gtMAC Layer Protocol Behavior
• 1. Bluetooth packet size selection
• 2. Backoff and scheduling.
• -gt Channel Selection
• Channels may be dynamically selected based on the
  channel status
• IEEE 802.11b DSSS selects a center channel
• Zigbee dynamically selects a channel at
  initialization and during normal
• Operation.
• Bluetooth may reduce its hopping set in
  response to channel
• assessment information.

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• -gt Modulation
• Spread spectrum techniques
• a transmission bandwidth that is several orders
  of magnitude greater
• than the minimum required signal bandwidth so
  that many users can
• simultaneously use the same bandwidth.
• Pseudorandom signal with noise-like properties
• Inherent interference rejection capability
• Elimination of narrowband interference
• Resistance to multipath fading due to frequency
  diversity.
• -gt Protocol Collaboration
• Collaborative methods rely on communication
  between different
• protocols at a specific protocol layer in order
  to achieve coexistence
• Protocols implemented on the same physical
  device can be
• collaborative
• Multi-radio and cognitive radio technologies

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Differences between Zigbee and Bluetooth
Zigbee Bluetooth
Application focus Monitoring and control Cable replacement
System resources 4KB-32KB 250KB
Battery life 100-1000 1-7
Network size Unlimited 7
Bandwidth 20-250 720
Transmission range 1-100 1-10
Success metrics Reliability, power, cost Cost convenience
Typical network join timeBluetooth 3
secondsZigBee 30 milliseconds
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similarities

• Bluetooth and ZigBee have much in common. Both
  are types of IEEE 802.15 "wireless personal-area
  networks," or WPANs. Both run in the 2.4-GHz
  unlicensed frequency band, and both use small
  form factors and low power.
• Bluetooth and Zigbee eliminates cabling between
  electronic products and accessories .
• They use spread spectrum modulation techniques.
•   They are both short range devices .

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ZigBees Future
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CONCLUSION

• The ZigBee Standard enables the broad-based
  deployment of reliable wireless networks with low
  complexity, low cost solutions and provides the
  ability for a product to run for years on
  inexpensive primary batteries. The mission of the
  ZigBee Working Group is to bring about the
  existence of a broad range of interoperable
  consumer devices by establishing open industry
  specifications for unlicensed, control and
  entertainment devices requiring the lowest cost
  and lowest power consumption communications
  between compliant devices anywhere in and
  around the home.

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ANY QUERIES??
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• THANKYOU