1. ZigBee, A Suitable Base For Embedded Wireless Development? 김백규

2. Contents 1. Methods for answering the research questions 2. ZigBee 3. ZigBee Development Environment 4. ZigBee Demonstrator Application 5. Alternatives to ZigBee 6. Discussion and results

3. Methods for answering the research questions

4. The main question Is ZigBee a suitable technology for embedded wireless development?

5. Support questions How much work is involved in building an application using ZigBee? What are the practical limitations? How secure is ZigBee? Which transceivers and development kits are on the market? What are the alternatives to ZigBee? What uses are suitable for ZigBee? What problems are involved in developing with a beta version of the standard?

6. ZigBee

7. What is ZigBee? ZigBee is aimed at applications where…  Low power consumption is desired.  Low data rates are acceptable. Self organizing mesh networks ZigBee intends to be a complement to existing wireless standards and not a competitor.  Aims to be used in areas where most existing wireless standards are not suitable.

8. Key features of complementary wireless protocols

9. The IEEE 802.15.4 standard(1/2) The ZigBee standard only defines high level network behavior. The lower layers are defined by the IEEE 802.15.4 standard. Properties  Low power consumption  Low data rate  Low hardware costs  Low sensitivity of interference  Short to medium range communications

10. The IEEE 802.15.4 standard(2/2)

11. The ZigBee standard(1/5) Defines the Network and Application layer.  The Network layer provides… Routing : possible to create very large networks.

12. The ZigBee standard(2/5) Power consumption  Non-beaconed mesh networks is commonly used.  Since there are no beacons to listen for, end devices can set their own duty cycle.  Waking up from power down mode only when they transmit or request data.  Advantages : very low power consumption for end devices  Disadvantages : higher power consumption for routers and coordinators.

13. The ZigBee standard(3/5) What is Application profiles  Standardized way of describing device capabilities. Capabilities are described by Clusters of Attributes.  Attributes are basically variables.  Attributes can be read or written by remote devices using key value pair(KVP) packets. The ZigBee Alliances intends to define several application profiles.  Profiles define : clusters, attributes, data types, valid ranges, a set of numeric constants.  Each profile covers a specific class of devices.

14. The ZigBee standard(4/5) A schematic view of parts of the Home Control Lighting profile.

15. The ZigBee standard(5/5) Suitable areas for ZigBee

16. ZigBee Development Environment

17. Introduction The following choices was examined  Frequency band  Transceiver  Network stack  Development kit

18. Frequency band The 2.4 GHz band was chosen.  Because it is supported globally and most likely to be used in ZigBee products.

19. Transceivers and Network Stack The CC2420 transceiver from Chipcon is used in this project.  It appears to be the best on the market performance wise.  It is also the most common transceiver in ZigBee development kits. Network Stack.  Licensed from a third party.

20. Development kits Chosen the CC2420 DK from Chipcon.  The most complete network stack.  The best transceiver and shortest delivery time.

21. Contents of the CC2420 ZigBee development kit

22. Chipcon CC2420 ZigBee development kit(1/2) 5 CC2420 demonstration boards Packet sniffer with a CC2420 module Atmel JTAG1 ICE2 mk II in-circuit programmer ZigBee network stack, Z-Stack 0.92 Cables, power supplies and battery holders.

23. Chipcon CC2420 ZigBee development kit(2/2) The major componets of the CC2420 demonstration boards. - CC2420 transceiver - Atmel ATmega128 microcontroller – 4 kb RAM – 4 kb EEPROM – 128 kb Flash - 64kb external memory - Printed circuit board antenna - Two buttons - 4-way joystick with push function - Four light emitting diodes - Temperature sensor - Potentiometer - RS-232 serial connector

24. Z-Stack(1/2) Currently supports two 802.15.4 transceivers.  Chipcon CC2420, Freescale MC13192 Written in ANSI C The Z-Stack is based on version 0.92 of the ZigBee standard. It has most functionality for building a ZigBee application.

25. Z-Stack(2/2) But with several important shortcomings. - Stability issues after long running time - Device discovery is very primitive - Routes can not be repaired and do not expire in mesh mode - End devices are sometimes dropped from the coordinators routing tables - No option to enable hardware encryption - Effective data rate is limited to a few packets per second. - The Serial Port Interface has a lot of bugs

26. ZigBee Demonstrator Application

27. Schematic view of the demonstration system

28. Purpose of the application How much work is involved in building an application using ZigBee? Suitable areas for ZigBee? What are the practical limitations? What problems are involved in developing with a beta version of the standard?

29. Demonstrations Demonstrated the following - Network setup - Different nodes find each other - Message replies - Application messages sent to: - Get values - Set values - Trigger events - Interactive system - Automatic system - Monitoring of the network: - Node to node communication - Topologies -Node states Could not be demonstrated  Dynamic routing  Secure transfer

30. Demonstration scenario Four nodes  Coordinator connected to a PC  Temperature sensor  Fan controller  Remote control with a display Remote control  See the state of the fan  Turn the fan on and off  View the trigger level  Change the trigger level  Enable or disable automatic temperature updates  Change the interval of automatic temperature updates.

31. Testing Range  Outdoors range 120meters.  Indoor range about 20meters Practical data rate  About one packet per second. Topology  Mesh network does work.

32. Alternatives to ZigBee

33. Network based alternatives Z-Wave - Large networks, mesh topology - 96 kbps data rate - Years of battery time for non-routing nodes - Stack size of <32 kB, low complexity -100 m line of sight range, 30 m indoors - Low cost

34. Network based alternatives Insteon - Large networks, mesh topology - 10 messages per second data rate - Years of battery time for non-routing nodes - Low complexity - 50 meter range, wires possible - $20 retail cost per unit

35. Network based alternatives Bluetooth - 8 node networks, star topology - 1 Mbps data rate - Days of battery time - Stack size of approximately 250kB, high complexity - 10-100 meter range - Node cost of $5 in large volumes

36. Network based alternatives WirelessUSB - Small networks, star topology - 62.5 kbps data rate - Years of battery time - Stack size of 4kB, very low complexity - 50 meters range - Node cost of $3 at 100,000 units

37. Network based alternatives XMesh - Large networks, mesh topology - Low data rate - Years of battery time for non-routing nodes - Low complexity - 100 meter line of sight range - Node cost of $5 cost at large volumes

38. Network based alternatives LonWorks - 32,000 nodes, mesh topology - 1.25 Mbps data rate - Design for mains power - High complexity - Primarily for wired communication - High cost

39. Internal threats The largest threat to ZigBee as the global standard for low data rate and low power networks are within the ZigBee Alliance itself. Although ZigBee is built on top of an open IEEE standard, the ZigBee standard itself is not often. Requirements for selling products under the ZigBee brand is currently unresolved.  The market for ZigBee is price sensitive and high certification costs might prevent adoption of the standard. The scope of the standard is another problem.  By trying to cover virtually every wireless area, ZigBee may be aiming too high.  creating standard which is more complex than necessary.

40. Discussion and results

41. Original questions How much work is involved in building an application using ZigBee? What are the practical limitations? How secure is ZigBee? Which transceivers and development kits are on the market? What are the alternatives to ZigBee? What uses are suitable for ZigBee? What problems are involved in developing with a beta version of the standard?

42. How much work is involved in building an application using ZigBee? ZigBee’s design is very simple and easy to learn. The custom profile used in this application was both easy and straightforward to define. Development time for a ZigBee application was short. No extra implementation is required in existing nodes when new ones ar added to the network.  Development time can be expected to only increase linearly.

43. What are the practical limitations? Line of sight range is about 120meters and indoor range is significantly lower. Multiple non-load bearing walls can be penetrated without packet loss. Practical data rate : 1 packet per second. The low power consumption is for end devices only.  If routers are not mains powered the practical life span of the network will be fairly short.  The battery time of end devices is irrelevant if they can not reach the rest of the network. This is a large disadvantage that is almost never mentioned in ZigBee advertisement material.

44. How secure is ZigBee? Version 1.0 looks secure, but the version used did not support security so it could not be tested. ZigBee supports 128-bits AES encryption built into the transceiver itself.

45. Which transceivers and development kits are on the market? The ZigBee DK from Chipcon, using Chipcon’s CC2420 transceiver was used in this projects and it seemed like best possible development kit available. Beside the bugs and limitations in the included Z-Stack, there have been no problems with the kit itself.

46. What are the alternatives to ZigBee? There are currently no alternative to ZigBee as the broad global standard for low rate, low power networks. However, there are several competitor in specific areas.

47. What uses are suitable for ZigBee? ZigBee is suitable for both building automations and industrial networks. It is most likely to be successful in security and climate control for homes and offices and in industrial networks,

48. What problems are involved in developing with a beta version of the standard? The major problem is the lack of documentation. When implementing software using a beta version of the standard expect it to take longer time.  Errors will occur even though the application implementation is correct.  Some thing might not be possible to do at all.

49. Conclusions

50. ZigBee is a suitable base for embedded wireless development.  The main reason is that development is easy and fast. The areas that ZigBee is likely to be used in is building automation and industrial networks.  The chances seem highest in the industry since ZigBee is currently the only option for such standardized wireless networks.