16-07-2011, 04:00 PM
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ZIGBEE
Wat is Zigbee?
Characteristics
ZigBee-based wireless devices operate in 868 MHz,915 MHz, and 2.4 GHz frequency bands.
The maximum data rate is 250 K bits per second.
What Does ZigBee Do?
Designed for wireless controls and sensors
Operates in Personal Area Networks (PAN’s) and device-to-device networks
Connectivity between small packet devices
Control of lights, switches, thermostats, appliances, etc.
IEEE 802.15.4 Device Types
Three device types
Network Coordinator
• Maintains overall network knowledge; most sophisticated of the three types; most memory and computing power
Full Function Device
• Carries full 802.15.4 functionality and all features specified by the standard
• Additional memory, computing power make it ideal for a network router function
• Could also be used in network edge devices (where the network touches the real world)
Reduced Function Device
• Carriers limited (as specified by the standard) functionality to control cost and complexity
• General usage will be in network edge devices
• All of these devices can be no more complicated than the transceiver, a simple 8-bit MCU and a pair of AAA batteries!
Comparison
Power Consumption
Complexity
Cost
Topologies
Star Topology
Peer to peer topology
Mesh Topology
Mesh networks
Coordinators
A coordinator, which organizes the
network and maintains routing tables.
■ Routers, which can talk to the coordinator, to other routers and to reduced-function end devices.
End devices
Reduced-function end devices, which
can talk to routers and the coordinator, but
not to each other.
A mesh network
Advantages
Reliable
Supports large number of nodes
Easy to deploy
Very long battery life
Secure
Low cost
Can be used globally
Home automation