Zigbee is an emerging worldwide standard for
Wireless Personal Area Networks (WPAN).
Defined rate of 250 kbit/s on 2.4 Ghz frequency,
best suited for a single signal transmission from a
sensor or input device.
Network based on IEEE 802.15.4 standard.
low cost, low power, wireless mesh network
Applications include wireless light switches,
electrical meters with in-home-displays, traffic
management systems, and other consumer and
WHY WE NEED ZIGBEE!
There are many standards that address mid to high
data rates for voice, PC LANs, video, etc.
However, up till now there hasn’t been a wireless
network standard that meets the unique needs of
sensors and control devices.
Wireless sensor networks
Medical data collection
Smoke and intruder warning
Zigbee devices are of three types:
1) ZigBee coordinator (ZC)
The main device, the coordinator forms the network tree
and is a bridge to other networks. There is exactly one
ZigBee coordinator in each network it stores information
about the network, including acting as the Trust Center
& repository for security keys.
2) ZigBee Router (ZR)
As well as running an application function, a router can
act as an intermediate router, passing on data from
3)ZigBee End Device (ZED)
Contains just enough functionality to talk to the parent
node (either the coordinator or a router); it cannot relay
data from other devices.
HOW ZIGBEE WORKS
It works in the unlicensed 2.4 GHz (worldwide), 915 MHz
(Americas and Australia) and 868 MHz (Europe) ISM bands.
Sixteen channels are allocated in the 2.4 GHz band, with each
channel requiring 5 MHz of bandwidth.
It is built on a single chip which reduces its cost and power
It has few analog stages and uses digital circuits wherever
The radios use direct-sequence spread spectrum coding,
which is managed by the digital stream into the modulator.
Binary phase-shift keying (BPSK) is used in the 868 and 915
MHz bands, and offset quadrature phase-shift keying
(OQPSK) that transmits two bits per symbol is used in the 2.4
The current ZigBee protocols support beacon and non-beacon
Frequency Data Rate Indoor Outdoor
2.4Ghz 250kb/s 10 to 20m 1500m
915Mhz 40kb/s - 1000m
868Mhz 20kb/s - 800m
ZIGBEE NETWORK &SECURITY
Searches for a Radio Channel.
Automatically assigns PAN(Personal Area
ZIGBEE NETWORK &SECURITY
ZigBee uses 128-bit keys to implement its security
Initial master key must be obtained through a secure
medium (transport or pre-installation), as the security of
the whole network depends on it.
A secure network will designate one special device
which other devices trust for the distribution of security
keys: the trust center.
The MAC sub layer is capable of single-hop reliable
The network layer manages routing, processing
received messages and being capable of broadcasting
The application layer offers key establishment and
transport services to both ZDO and applications.
ADVANTAGES OF ZIGBEE
Low power consumption.
They are more ecological saving megawatts at its
Low cost (device, installation, maintenance).
High density of nodes per network(using IEEE
802.15.4 PHY and MAC).
SIMULATION OF ZIGBEE NETWORKS
NS2, OPNET, and NetSim can be used using C++.
Simulation on Opnet