1 / 25

ZigBee

ZigBee. Alex Wegznek Chris Griffis EEL 4514 Communications System. Overview. ZigBee Overview Purpose of ZigBee History of ZigBee How ZigBee works Pros & Cons Regulations & Standards Stack & Protocol Comparisons. ZigBee Overview.

iman
Download Presentation

ZigBee

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ZigBee Alex Wegznek Chris Griffis EEL 4514 Communications System

  2. Overview • ZigBee Overview • Purpose of ZigBee • History of ZigBee • How ZigBee works • Pros & Cons • Regulations & Standards • Stack & Protocol • Comparisons

  3. ZigBee Overview • Specification for communication protocols based upon IEEE 802.15.4 standard • Wireless sensor monitoring and control • Designed to be: • Highly reliable • Cost-effective • Low-power • Highly secure • Low-data rate http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.science.smith.edu%2F~jcardell%2FCourses%2FEGR390%2FReadings%2FZigBee-Tutorial.ppt&ei=S45vUL2MIpOY9QS164GADQ&usg=AFQjCNFTM-NOUd01KZbHOteELxu737imrQ

  4. Purpose • Provide reliable and cost effective solution for WPANs • Designed specifically for sensor networking and automation • Intended to fit on 8-bit microcontrollers with 16 and 32-bit solutions available • Low power leads to extended battery life

  5. History • Conceived around 1998 • Grew out of the realization that Wi-Fi and Bluetooth were unsuitable for many applications • The first IEEE 802.15.4 standard was finished in 2003 • ZigBee PRO (new standard) was finished in 2007 • ZigBee PRO has extra features: multi-casting, many-to-one routing, and more

  6. ZigBee Alliance • Formed in 1997 with 8 original promoter companies and now has over 200 members • Maintains and publishes the ZigBee standard

  7. Markets • Home Control • Automation, smart lighting, security, temperature control • Commercial Building Automation • Wireless Sensor Networks • Industrial Control • Embedded Sensing http://www.ti.com/lsds/ti/analog/zigbee.page?DCMP=hpa_rf_general&HQS=NotApplicable+OT+zigbee

  8. How does it work? • Mesh networking • Ad-hoc network • Nodes can forward data to other nodes which is called hopping • Multi-hopping can give the network extended range as well as avoid barriers • Tree and star routing also available

  9. How does it work? (Cont.) Low Power Low-Data Rate • Devices have low duty cycle • No constant contact • Allows devices to operate for the entire shelf life of the battery • Leads to low data rates • Ideal for sensor networks • Due to low cost/power • 250 kbps maximum • Actual throughput comes out closer to 25 kbps • Transceivers are half duplex • Can only receive or transmit at one time http://www.digikey.com/us/en/techzone/energy-harvesting/resources/articles/Ultra-Low-Power-MCUs.html

  10. How does it work? (Cont.) High Level of Security High Reliability • National Institute of Standards and Technology (NIST) Advanced Encryption Standard (AES) • AES-128 bit block cipher algorithm • ZigBee both encrypts and authenticates packets • Carrier sense multiple access with collision avoidance (CSMA-CA) • 16 bit cyclic redundancy check (CRC); parity bit • Mesh network finds route and acknowledges each hop • End-to-end data arrival acknowledgements

  11. How does it work? (Cont.) Direct-sequence spread spectrum (DSSS) Offset Quadrature Phase-Shift Keying (OQPSK) Binary Phase-Shift Keying (BPSK) • 868 and 915 MHz band • Simplest form of phase shift keying, also the most robust • Takes the highest level of noise/distortion to cause an incorrect decision by the demodulator • Only able to modulate at 1 bit/symbol (slow data rate) • 2.4 GHz band • Uses 4 different values of the phase to transmit • Offset reduces any unwanted amplitude fluctuation • Transmits twice the data rate in a given bandwidth as compared to BPSK

  12. Pros and Cons Pros Cons • High reliability • Low cost • Ultra Low power • Highly secure • Open global standard • Remote operation • Easy to implement • Self healing networks • Low data rate • Relatively small transmission range if hopping is not used (10-75 m)

  13. Regulations & Standards • IEEE 802.15.4 low rate WPAN standard • Uses the ISM bands • OQPSK - 2.4GHz band • BPSK – lower bands • 250 kbps, 40 kbps, and 20 kbps http://evolt-ektor.com/zigbee-as-a-wireless-network

  14. Regulations • 16 channels: 5 MHz of BW each • All 16 channels because low BW protocol • Interference tolerant • Fc = (2350 + (5*ch))MHz where ch = 11,12,…26 http://www.intechopen.com/books/factory-automation/wireless-sensor-networks-for-networked-manufacturing-systems

  15. Standards • Lower protocol specifications • IEEE 802.15.4 defines how to: • Discover networks • Form & join networks • Change channels • Detect interference • Single hop, broadcast and data-packet delivery method bwrc.eecs.berkeley.edu/people/grad_students/.../zigbee%20master.ppt

  16. Stack • Simple Stack – easy for user • Physical layer - direct sequence, cheap, high integration • MAC layer – several topologies, works with many devices • Network layer – control, communication, and monitoring the nodes http://www.tutorial-reports.com/wireless/zigbee/zigbee-architecture.php

  17. Stack (Cont.) • MAC and PHY layers are under IEEE control • The physical layer is the circuitry • The MAC layer allows networks to form and for data transfer • ZigBee assures security, multi-hops, and interoperability • ZigBee’s security differs from IEEE 802.15.4 • The APS layer has tables to keep track of which nodes it can accept data from • User only worries about task ZigBee Wireless Networking, Drew Gislason

  18. Topologies • Star, Peer-to-Peer, & Mesh • ZigBee network layer has 3 device types: coordinator, router, and end device • Network layer deals with network discovery, formation, address allocation, message routing, network wide security • The APS layer uses the address tables to act as a filter http://www.tutorial-reports.com/wireless/zigbee/zigbee-characterstics.php

  19. Protocol • Coordinator • Forms network • Monitor/establish/maintains network • Chooses channel • Acts as the trust center • Can act as a router • Router • Finds and joins networks • Pushes broadcasts along • Maintains routes • Stores data for sleeping end devices http://www.zigbee.org/

  20. Protocol (Cont.) • End devices • Most often sleeping • Periodically wake to check if their parent nodes have anything for them • They perfom their tasks • Send data if necessary • Back to sleep • Orphaned nodes will find new parents

  21. Protocol (Cont.) • Fully reliable hand-shake data transfer protocol • Error detection and retransmission • ZigBee communicates similar to us • Collision avoidance • Cannot listen and talk at same time • Designed to minimize time the radio is on • Beaconing (asleep) • Non-beaconing (always on) https://docs.zigbee.org/zigbee-docs/dcn/06/docs-06-4513-00-00mg-zigbee-network-layer-technical-overview.pdf

  22. Comparisons

  23. When to choose ZigBee • Infrequent, small data packets • Many nodes • Timing is critical • 30 ms to add a new slave • 15 ms to wake up • Lots of devices http://www.wirelessdesignmag.com/ShowPR.aspx?PUBCODE=055&ACCT=0000100&ISSUE=1209&RELTYPE=blog&PRODCODE=000000&PRODLETT=ES&CommonCount=0

  24. Questions?

  25. Additional References • http://www.tutorial-reports.com/wireless/zigbee/zigbee-architecture.php • http://www.newcircuits.com/article.php?id=tut004 • http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.science.smith.edu%2F~jcardell%2FCourses%2FEGR390%2FReadings%2FZigBee-Tutorial.ppt&ei=S45vUL2MIpOY9QS164GADQ&usg=AFQjCNFTM-NOUd01KZbHOteELxu737imrQ • Zigbee.org • bwrc.eecs.berkeley.edu/people/grad_students/.../zigbee%20master.ppt

More Related