18-01-2013, 03:20 PM
ZigBee : Wireless Control
ZigBee 1.pptx (Size: 3.1 MB / Downloads: 40)
Introduction
ZigBee is designed to be a low power, low cost, low data rate, wireless solution.
ZigBee is a technological standard designed for control and sensor networks
Based on the IEEE 802.15.4 Standard
Created by the ZigBee Alliance
Operates in Personal Area Networks (PAN’s) and device-to-device networks
Connectivity between small packet devices
Control of lights, switches, thermostats, appliances, etc.
Specification of protocols for small, low-power radios
Monitor and sensor applications that need to have a battery life of years on alkaline batteries
Example – security systems, smoke alarms
History
Development started 1998, when many engineers realized that WiFi and Bluetooth were going to be unsuitable for many applications
IEEE 802.15.4 standard was completed in May 2003
The ZigBee specifications were ratified on 14 December 2004.
The ZigBee Alliance announced public availability of Specification 1.0 on 13 June 2005.
Much research is still going on with ZigBee.
In-Home Patient Monitoring
Patients receive better care at reduced cost with more freedom and comfort---
Patients can remain in their own home
Monitors vital statistics and sends via internet
Doctors can adjust medication levels
Allows monitoring of elderly family member
Sense movement or usage patterns in a home
Turns lights on when they get out of bed
Notify via mobile phone when anomalies occur
Wireless panic buttons for falls or other problems
Can also be used in hospital care
Patients are allowed greater movement
Reduced staff to patient ratio
ZigBee – Highly Secure
Encryption specified for MAC, Network and APS layers
Encryption/Authentication mode CCM(CTR +CBC-MAC)
CTR is a counter based encryption mode
CBC-MAC provides data integrity
All security is based on 128bit key and AES-128 block encryption method
Authentication and encryption
Security can be customized for the application
How A ZigBee Network Forms
Devices are pre-programmed for their network function
Coordinator scans to find an unused channel to start a network
Router (mesh device within a network) scans to find an active channel to join, then permits other devices to join
End Device will always try to join an existing network
Devices discover other devices in the network providing complementary services
Service Discovery can be initiated from any device within the network
Devices can be bound to other devices offering complementary services
Binding provides a command and control feature for specially identified sets of devices
Wireless Networking Basics
Network Scan
Device scans the 16 channels to determine the best channel to occupy.
Creating/Joining a PAN
Device can create a network (coordinator) on a free channel or join an existing network
Device Discovery
Device queries the network to discover the identity of devices on active channels
Service Discovery
Device scans for supported services on devices within the network
Binding
Devices communicate via command/control messaging