1. ZigBee Technology
家庭網路設備設計與控制

2. Outline ZigBee Introduction ZigBee Network ZigBee protocol stack
Network Configurations
Network topology
Data Transmission
Power Consumption
ZigBee protocol stack
Application layer
Network layer
Medium access control layer
Physical layer
ZigBee Application

3. From Popular Science Magazine

4. The IEEE 802 Wireless Space
WWAN
IEEE
IEEE
WMAN
Range
WiMax
IEEE
WLAN
WiFi
802.11
ZigBee
15.4c c
Bluetooth
WPAN
0.01
0.1 1 10
100
1000
ZigBee standard uniquely fills a gap for low data rate applications
Data Rate (Mbps)

5. Sensor/Control Network Requirements
Networks form by themselves, scale to large sizes and operate for years without manual intervention
Extremely long battery life (years on AA cell),
low infrastructure cost (low device & setup costs)
low complexity and small size
Low device data rate and QoS
Standardized protocols allow multiple vendors to interoperate

6. ZigBee Alliance Overview-
Organized as an independent, neutral, nonprofit corporation in 2002
Open and global
Anyone can join and participate
Membership is global
Activity includes
Specification creation
Certification and compliance programs
Branding, market development, and user education

7. The ZigBee Promoters

8. What is ZigBee
ZigBee is a wireless communication standard that provides a short-range cost effective networking capability.
It has been developed with the emphasis on low cost battery powered applications, such as building automation, industrial and commercial controls, marine wireless, personal healthcare.
The IEEE and ZigBee Alliance have introduced ZigBee to provide the first general standard for these applications.

9. ZigBee Applications ZigBee Wireless Control that Simply Works security
BUILDING
AUTOMATION
CONSUMER ELECTRONICS
security
HVAC
AMR
lighting control
access control TV
VCR
DVD/CD
remote
ZigBee
Wireless Control that
Simply Works
PC & PERIPHERALS
PERSONAL HEALTH CARE
patient monitoring
fitness monitoring
mouse
keyboard
joystick
TELECOM SERVICES
INDUSTRIAL
CONTROL
HOME CONTROL
asset mgt
process control
environmental
energy mgt
security
HVAC
lighting control
access control
irrigation
m-commerce
info services
object interaction (Internet of Things)

10. ZigBee Advantages Low cost Low power consumption
Licence free operation in the 2.4GHz 868MHz and 915MHz bands
Hundreds of devices per network
Network flexibility - Star, Cluster tree or Mesh configuration

11. ZigBee Radio Layer
The ZigBee standard utilizes IEEE standard as radio layer( MAC and physical layer ) 。
Three radio bands are defined：
Global use：ISM 2.4GHz band with 16 channels and data rate of 250kb/s；
USA and Australia：915MHz band with 10 channels and data rate of 40kb/s；
Europe：868MHz band with single channel and data rate of 20kb/s。

12. Market Comparisons

13. ZigBee Device Member Three kinds of member in ZigBee network
Coordinator:
response for initializing, maintaining, and controlling the network
Router:
which have capability to participate in the routing procedure
End Device:
transmit and receive frames through their parent node

14. ZigBee Device Type
The ZigBee architecture recognizes two types of device：
RFD ( Reduced Function Device )
The RFD has limited resources and does not allow some advanced functions( e.g. routing ) as it is a low cost end device solution。
FFD ( Full Function Device )
Each ZigBee network has a designated FFD that is a network coordinator acts as the administrator and takes care of organization of the network。

15. ZigBee Network
The ZigBee network is managed by a network coordinator，it can starts the network，takes care of the structure and controls the joining and leaving of the devices in the network。
If a device intends to join an existing network it has to start network association procedure ( send an authentication request ) that is answered by the coordinator within a predefined time。
If the device intends to leave the network，the device issues a disassociation request。

16. Network Association Procedure

17. ZigBee Network – cont’d
Network Configurations
The IEEE employs the long 64-bit address( IEEE ) and a short 16-bit addresses。
The short address is assigned by the network coordinator when a device joins the network and is unique within the given network。
The short address supports over nodes per network。
The short address of a network coordinator is 0x00。
The network identificator ( PAN ID ) is a 16-bit number that is used to distinguish between overlaying networks。
To join a network the device has to know the PAN ID of the network it intends to associate。
The IEEE MAC enables network association and disassociation。

18. ZigBee Network – cont’d
Network Configurations
The medium access method to the channels is carrier sense multiple access with collision avoidance ( CSMA-CA ) 。
The ZigBee uses the direct sequence spread spectrum ( DSSS ) modulation method。

19. ZigBee Network Topologies
Mesh
Star
ZigBee Coordinator
Cluster Tree
ZigBee Router
ZigBee End Device

20. ZigBee Network – cont’d
Network Topology - ZigBee star topology
Constructed with one coordinator in the center and the end devices。
The device in the topology can only communicate via the network coordinator。
The start topology is necessary for RFD devices as they are not capable of routing。
Network coordinator
Reduced Function Device
Full Function Device

21. ZigBee Network – cont’d
Network Topology –
ZigBee mesh topology
The ZigBee also supports a mesh topology，sometimes called cluster-tree。
Here the FFD devices in the network may communicate without the aid of the network coordinator。
These nodes serves as routers in the network，forming a reliable network structure with healing abilities。
Network coordinator
Reduced Function Device
Full Function Device

22. ZigBee Network – cont’d
Network Topology –
ZigBee tree topology
Is a multiple star topoloty with one central node that is the ZigBee network coordinator。
The multiple-hop topology networks must support routing，so their network administration is more complex。
Network coordinator
Reduced Function Device
Full Function Device

23. ZigBee Network – cont’d
Network Topology –
Star clusters in the mesh topology
Where only RFD devices participate through a FFD router device and of mesh links between the FFD devices。
The star links are necessary for the RFD devices in the mesh topology as they are able to communicate with a single FFD only。
Network coordinator ( FFD )
Network End Device ( RFD，FFD )
Network Router ( FFD )

24. ZigBee Network – cont’d
Data Transmission
To allow for real-time transmssions the ZigBee there are defined two different data transmission mechanisms。
Non-beacon enabled network
The standard CSMA/CA takes place
Any node may start the transmission at any time as long as the channel is idle。
Beacon enabled network
The nodes are allowed to transmit in predefined time slots only。
The coordinate sends a beacon frame ( superframe ) and nodes are expected to synchronize to this frame。

25. ZigBee Network – cont’d
Power Consumption
ZigBee is designed for applications that need to transmit small amounts of data while being battery powered。
The architecture of the protocols and the hardware is optimized for low power consumption of the end device。
The coordinator and routing devices should not be battery powered as these should be able to receive and transmit all the time。
Ex : in the star topology
Device Wake up from power saving mode.
Receive beacon frame and sends data to the coordinator.
Goes to power saving mode again.
The coordinator stores data and other end device poll for the data the data are delivered.
Disadvantage: the coordinator might lead to large RAM needs.

26. ZigBee Compliant Platform [ZCP]
Application
ZDO
SSP
App Support (APS) {
NWK
ZigBee Compliant Platform
Physical Radio (PHY)
Medium Access (MAC)
Platform certification - ensures all parts of the stack other than the application are compliant with the ZigBee Standard
Allows Network interoperability but does not imply interoperability at the application layer
There are currently 30 Compliant Platforms to choose from

27. Application Profiles
Application
ZDO
SSP
App Support (APS)
NWK
Clusters
Clusters
Physical Radio (PHY)
Medium Access (MAC)
0: off
1: on
2: scene 1
3: scene 2
0: fan off
1: fan on
2: temp set
3: time set
Application profiles define what messages are sent over the air for a given application
Devices with the same application profiles interoperate end to end
ZigBee publishes a set of public profiles, but vendors may create manufacturer specific ones as well

28. Manufacturer Specific Profiles{
Application
ZDO
SSP
App Support (APS)
Certification testing ensures application does not interfere with other ZigBee networks
NWK
Physical Radio (PHY)
Medium Access (MAC)
Allows a vendor to build specialized products with a ZigBee Compliant Platform
Certification testing ensures their product does not harm other ZigBee networks
Manufacturer specific applications are not intended to interoperate at the application layer
Allows product vendor to use ZigBee language and logos on their product

29. ZigBee Public Profiles{
Application
ZDO
SSP
App Support (APS)
Ensures application conforms to a specific public application profile
NWK
Physical Radio (PHY)
Medium Access (MAC)
Guarantees interoperability between products all running the same public application profile
Product vendors may add additional features to the public profiles
Allows product vendor to use ZigBee language and logos on their product

30. ZigBee Protocol Stack
The ZigBee stack forms the upper layers of the IEEE PHY and MAC sub-layer specifications。
ZigBee stack layers include a network layer，an application layer and a security service provider ( SSP ) 。
It realizes the network layer ( NWK ) and in the application layer provides application support sub-layer( APS ) and the ZigBee device object ( ZDO ) 。
In the framework are added the user defined application objects。
ZigBee standard stack architecture

31. ZigBee Protocol Stack – cont’d
In the ZigBee applications are use several principal terms that are explained below :
Attribute : represents a data entity that may refer to some physical quantity.
Cluster : a set of attributes forms a cluster. It described the messages received and transmitted by the device. Cluster is identified by a 8-bit number and it has to be unique within the given profile.
Device description : each device is described by a device descriptor. It describes the type of the device and the incoming and outcoming messages of each endpoint on the device.

32. ZigBee Protocol Stack – cont’d
Endpoint : is an application on a physical device identified by its address and supports application within a single profile. One physical device may support several endpoints from different profiles. There are up to 240 endpoints available on a single device.
Profile : is a set of device descriptions forming a reasonable application. The description within a profile includes definition of the endpoints，message clusters and the services provided by the device. Profiles are managed by the ZigBee Alliance for allocating the unique profile identifier for each profile. The profile identifier is a 16-bit number that may be obtained from the ZigBee Alliance only.

33. ZigBee Protocol Stack – cont’d

34. ZigBee Protocol Stack – cont’d
The profile are the base that enables interoperability of device from different vendors and even different versions.
Once the profile is developed it shall be submitted to the ZigBee Allicance that will allocate the profile identifier.
The profile to start with when creating an application if no suitable existing profile is available would be naturally the generic profile.
Within the profile is the most important part the definition of the messages passed between the devices and the type of available devices.

35. ZigBee Protocol Stack – cont’d
ZigBee device type architecture

36. ZigBee Protocol Stack – cont’d
Application Layer
The application layer carries the code of the individual custom application.
According to the ZigBee specification this code is written into the ZigBee Device Object ( ZDO ) and the function of the device is specified.
The application support sublayer ( APS ) forms the low level of the application layer.
Here is the binding and discovery of neighburing device handled and also responsible for forwarding of message among devices that are not able to communicate directly.
Binding is the ability to match different but compatible devices together ， such as a switch and lamp.

37. ZigBee Protocol Stack – cont’d
Network Layer ( NWK )
Handles the network level of the communication.
It is managing the network structure and handles routing and security functions for the relayed messages.
The network layer needs to maintain the information about the nodes within the network.
The properties and parameters of the network are specified in the application as stack configuration of the network layer.

38. ZigBee Protocol Stack – cont’d
Medium Access Control Layer
Controlling access to the shared radio channel and It generates and recognizes the addresses ，verifies the frame check sequence.
The MAC layer is also responsible for the scheduling of the frame transmissions in the non beacon mode and beacon mode.
In the non beacon mode using CSMA/CA method. In this mode every node listen to the channel prior to starting its transmission ( free channel assessment ).
After the channel is found to be free the node starts it transmission. When the node suspects a collision it quits transmitting and waits for a random period to retry.

39. ZigBee Protocol Stack – cont’d
Medium Access Control Layer
In the beacon mode there is an optional superframe structure employed.
The superframe is started by the beacon and followed by 16 equal time slots. The first nine slots can be used by any device. The following seven slots ( denoted as GTS – Guaranteed Time Slots ) are reserved and can be allocated by individual devices by a request .

40. ZigBee Protocol Stack – cont’d
For low-latency application or some requiring specific data bandwidth
競爭區間
免競爭區間
閒置區
活動區間
Synchronize the attached devices
Identify the PAN
Describute the structure of the superframe
0≦BO≦14， 0≦SD≦14
BO:Beacon Order， SO:Superframe Order

41. ZigBee Protocol Stack – cont’d
Physical Layer
The physical layer is defined by the IEEE standard.
The modulation of the raw data is managed by DSSS modulator.
According to the standard IEEE the raw data bits are grouped into nibbles ( 4-bit groups ) and represent a symbol .
The 4-bits of nibble make 16 different symbols possible .
There is a look-up table that assigns to each of the symbol a 32-bit sequence that is called chipping code .
The chipping codes is presented to the modulator that construct the transmitted signal using half-sine plus construction .
In the 2.4Ghz band as physical layer is employed the OPQSK .
On the transceiver side the process is reversed .

42. Operating Frequency Bands
IEEE PHY Overview
Operating Frequency Bands
2.4 GHz
Channels 11-26
5 MHz
PHY
GHz
Direct sequence Spread spectrum (DSSS)

43. Positioning Techniques
Measurement of Distance
Time of arrival

44. Measuring Distance by RF Signal Strength
An experiment by IEEE b

45. Positioning by Trilateration
ideal situation
real situation

46. ZigBee Applications Sensors & Controls: Home Automation
Industrial Automation
Remote Metering
Automotive Networks
Interactive Toys
Active RFID/ asset tracking
Medical

47. ZigBee Home Control

48. ZigBee Home Lighting Network1 2 3 4 5 6 7 8 9 10 11 12

49. ZigBee Home Lighting Network1 2 3 4 5 6 7 8 10 10 10 9 11 12

50. ZigBee Home Lighting Network1 2 3 4 5 6 7 8 10 10 10 10 9 11 12

51. ZigBee Home Lighting Network1 2 3 4 5 6 7 8 10 10 10 9 11 12

52. The ZigBee eco-system adds future value
Safety
Asset Tracking
Security
Maintenance