26-06-2012, 12:20 PM
ROLE OF ZIGBEE TECHNOLOGY IN FUTURE DATACOMMUNICATION SYSTEM
[attachment=25545]
INTRODUCTION
ZigBee is an established set of specifications for
wireless personal area networking (WPAN),
i.e. digital radio connections between computers and
related devices. WPAN Low Rate or ZigBee
provides specifications for devices that have low
data rates, consume very low power and are thus
characterized by long battery life. ZigBee makes
possible completely networked homes where all
devices are able to communicate and be controlled
by a single unit. The ZigBee Alliance, the standards
body which defines ZigBee, also publishes
application profiles that allow multiple OEM
vendors to create interoperable products. The
current list of application profiles either published
or in the works are:
• Home Automation
• ZigBee Smart Energy
• Telecommunication Applications
• Personal Home
The relationship between IEEE 802.15.4 and
ZigBee is similar to that between IEEE 802.11 and
the Wi-Fi Alliance. For non-commercial purposes,
the ZigBee specification is available free to the
general public. An entry level membership in the
ZigBee Alliance, called Adopter, costs US$ 3500
annually and provides access to the as-yet
unpublished specifications and permission to create
products for market using the specifications.
ZigBee is one of the global standards of
communication protocol formulated by the relevant
task force under the IEEE 802.15 working group.
The fourth in the series, WPAN Low Rate/ZigBee
is the newest and provides specifications for
devices that have low data rates, consume very low
power and are thus characterized by long battery
life. Other standards like Bluetooth and IrDA
address high data rate applications such as voice,
video and LAN communications.
ZigBee devices are actively limited to a throughrate of 250Kbps, compared to Bluetooth's much
larger pipeline of 1Mbps, operating on the 2.4 GHz Journal of Theoretical and Applied Information Technology
ISM band, which is available throughout most of
the world.In the consumer market ZigBee is being
explored for everything from linking low-power
household devices such as smoke alarms to a
central housing control unit, to centralized light
controls.
The specified maximum range of operation for
ZigBee devices is 250 feet (76m), substantially
further than that used by Bluetooth capable devices,
although security concerns raised over "sniping"
Bluetooth devices remotely, may prove to hold true
for ZigBee devices as well. Due to its low power
output, ZigBee devices can sustain themselves on a
small battery for many months, or even years,
making them ideal for install-and-forget purposes,
such as most small household systems. Predictions
of ZigBee installation for the future, most based on
the explosive use of ZigBee in automated
household tasks in China, look to a near future
when upwards of sixty ZigBee devices may be
found in an average American home, all
communicating with one another freely and
regulating common tasks seamlessly.
The ZigBee Alliance has been set up as “an
association of companies working together to
enable reliable, cost-effective, low-power,
wirelessly networked, monitoring and control
products based on an open global standard”. Once a
manufacturer enrolls in this Alliance for a fee, he
can have access to the standard and implement it in
his products in the form of ZigBee chipsets that
would be built into the end devices. Philips,
Motorola, Intel, HP are all members of the Alliance
. The goal is “to provide the consumer with
ultimate flexibility, mobility, and ease of use by
building wireless intelligence and capabilities into
every day devices. ZigBee technology will be
embedded in a wide range of products and
applications across consumer, commercial,
industrial and government markets worldwide. For
the first time, companies will have a standardsbased wireless platform optimized for the unique
needs of remote monitoring and control
applications, including simplicity, reliability, lowcost and low-power”.
The target networks encompass a wide range of
devices with low data rates in the Industrial,
Scientific and Medical (ISM) radio bands, with
building-automation controls like intruder/fire
alarms, thermostats and remote (wireless) switches,
video/audio remote controls likely to be the most
popular applications. So far sensor and control
devices have been marketed as proprietary items for
want of a standard. With acceptance and
implementation of ZigBee, interoperability will be
enabled in multi-purpose, self-organizing mesh
networks
ZIGBEE CHARACTERISTICS
The focus of network applications under the IEEE
802.15.4 / ZigBee standard include the features of
low power consumption, needed for only two major
modes (Tx/Rx or Sleep), high density of nodes per
network, low costs and simple implementation.
These features are enabled by the following
characteristics,
• 2.4GHz and 868/915 MHz dual PHY modes. This
represents three license-free bands: 2.4-2.4835
GHz, 868-870 MHz and 902-928 MHz. The
number of channels allotted to each frequency band
is fixed at sixteen (numbered 11-26), one
(numbered 0) and ten (numbered 1-10)
respectively. The higher frequency band is
applicable worldwide, and the lower band in the
areas of North America, Europe, Australia and New
Zealand .
• Low power consumption, with battery life
ranging from months to years. Considering the
number of devices with remotes in use at present, it
is easy to see that more numbers of batteries need
to be provisioned every so often, entailing regular
(as well as timely), recurring expenditure. In the
ZigBee standard, longer battery life is achievable
by either of two means: continuous network
connection and slow but sure battery drain, or
intermittent connection and even slower battery
drain.
• Maximum data rates allowed for each of these
frequency bands are fixed as 250 kbps @2.4 GHz,
40 kbps @ 915 MHz, and 20 kbps @868 MHz.
• High throughput and low latency for low dutycycle applications (<0.1%)
• Channel access using Carrier Sense Multiple
Access with Collision Avoidance (CSMA - CA)
• Addressing space of up to 64 bit IEEE address
devices, 65,535 networks Journal of Theoretical and Applied Information Technology
• 50m typical range
• Fully reliable “hand-shaked” data transfer
protocol.
• Different topologies as illustrated below: star,
peer-to-peer, mesh
TRAFFIC TYPES
ZigBee/IEEE 802.15.4 addresses three typical
traffic types. IEEE 802.15.4 MAC can
accommodate all the types.
1. Data is periodic. The application dictates the
rate, and the sensor activates, checks for data and
deactivates.
2. Data is intermittent. The application, or other
stimulus, determines the rate, as in the case of say
smoke detectors. The device needs to connect to the
network only when communication is necessitated.
This type enables optimum saving on energy.
3. Data is repetitive, and the rate is fixed a priori.
Depending on allotted time slots, called GTS
(guaranteed time slot), devices operate for fixed
durations.
ZigBee employs either of two modes, beacon or
non-beacon to enable the to-and-fro data traffic.
Beacon mode is used when the coordinator runs on
batteries and thus offers maximum power savings,
whereas the non-beacon mode finds favour when
the coordinator is mains-powered.
[attachment=25545]
INTRODUCTION
ZigBee is an established set of specifications for
wireless personal area networking (WPAN),
i.e. digital radio connections between computers and
related devices. WPAN Low Rate or ZigBee
provides specifications for devices that have low
data rates, consume very low power and are thus
characterized by long battery life. ZigBee makes
possible completely networked homes where all
devices are able to communicate and be controlled
by a single unit. The ZigBee Alliance, the standards
body which defines ZigBee, also publishes
application profiles that allow multiple OEM
vendors to create interoperable products. The
current list of application profiles either published
or in the works are:
• Home Automation
• ZigBee Smart Energy
• Telecommunication Applications
• Personal Home
The relationship between IEEE 802.15.4 and
ZigBee is similar to that between IEEE 802.11 and
the Wi-Fi Alliance. For non-commercial purposes,
the ZigBee specification is available free to the
general public. An entry level membership in the
ZigBee Alliance, called Adopter, costs US$ 3500
annually and provides access to the as-yet
unpublished specifications and permission to create
products for market using the specifications.
ZigBee is one of the global standards of
communication protocol formulated by the relevant
task force under the IEEE 802.15 working group.
The fourth in the series, WPAN Low Rate/ZigBee
is the newest and provides specifications for
devices that have low data rates, consume very low
power and are thus characterized by long battery
life. Other standards like Bluetooth and IrDA
address high data rate applications such as voice,
video and LAN communications.
ZigBee devices are actively limited to a throughrate of 250Kbps, compared to Bluetooth's much
larger pipeline of 1Mbps, operating on the 2.4 GHz Journal of Theoretical and Applied Information Technology
ISM band, which is available throughout most of
the world.In the consumer market ZigBee is being
explored for everything from linking low-power
household devices such as smoke alarms to a
central housing control unit, to centralized light
controls.
The specified maximum range of operation for
ZigBee devices is 250 feet (76m), substantially
further than that used by Bluetooth capable devices,
although security concerns raised over "sniping"
Bluetooth devices remotely, may prove to hold true
for ZigBee devices as well. Due to its low power
output, ZigBee devices can sustain themselves on a
small battery for many months, or even years,
making them ideal for install-and-forget purposes,
such as most small household systems. Predictions
of ZigBee installation for the future, most based on
the explosive use of ZigBee in automated
household tasks in China, look to a near future
when upwards of sixty ZigBee devices may be
found in an average American home, all
communicating with one another freely and
regulating common tasks seamlessly.
The ZigBee Alliance has been set up as “an
association of companies working together to
enable reliable, cost-effective, low-power,
wirelessly networked, monitoring and control
products based on an open global standard”. Once a
manufacturer enrolls in this Alliance for a fee, he
can have access to the standard and implement it in
his products in the form of ZigBee chipsets that
would be built into the end devices. Philips,
Motorola, Intel, HP are all members of the Alliance
. The goal is “to provide the consumer with
ultimate flexibility, mobility, and ease of use by
building wireless intelligence and capabilities into
every day devices. ZigBee technology will be
embedded in a wide range of products and
applications across consumer, commercial,
industrial and government markets worldwide. For
the first time, companies will have a standardsbased wireless platform optimized for the unique
needs of remote monitoring and control
applications, including simplicity, reliability, lowcost and low-power”.
The target networks encompass a wide range of
devices with low data rates in the Industrial,
Scientific and Medical (ISM) radio bands, with
building-automation controls like intruder/fire
alarms, thermostats and remote (wireless) switches,
video/audio remote controls likely to be the most
popular applications. So far sensor and control
devices have been marketed as proprietary items for
want of a standard. With acceptance and
implementation of ZigBee, interoperability will be
enabled in multi-purpose, self-organizing mesh
networks
ZIGBEE CHARACTERISTICS
The focus of network applications under the IEEE
802.15.4 / ZigBee standard include the features of
low power consumption, needed for only two major
modes (Tx/Rx or Sleep), high density of nodes per
network, low costs and simple implementation.
These features are enabled by the following
characteristics,
• 2.4GHz and 868/915 MHz dual PHY modes. This
represents three license-free bands: 2.4-2.4835
GHz, 868-870 MHz and 902-928 MHz. The
number of channels allotted to each frequency band
is fixed at sixteen (numbered 11-26), one
(numbered 0) and ten (numbered 1-10)
respectively. The higher frequency band is
applicable worldwide, and the lower band in the
areas of North America, Europe, Australia and New
Zealand .
• Low power consumption, with battery life
ranging from months to years. Considering the
number of devices with remotes in use at present, it
is easy to see that more numbers of batteries need
to be provisioned every so often, entailing regular
(as well as timely), recurring expenditure. In the
ZigBee standard, longer battery life is achievable
by either of two means: continuous network
connection and slow but sure battery drain, or
intermittent connection and even slower battery
drain.
• Maximum data rates allowed for each of these
frequency bands are fixed as 250 kbps @2.4 GHz,
40 kbps @ 915 MHz, and 20 kbps @868 MHz.
• High throughput and low latency for low dutycycle applications (<0.1%)
• Channel access using Carrier Sense Multiple
Access with Collision Avoidance (CSMA - CA)
• Addressing space of up to 64 bit IEEE address
devices, 65,535 networks Journal of Theoretical and Applied Information Technology
• 50m typical range
• Fully reliable “hand-shaked” data transfer
protocol.
• Different topologies as illustrated below: star,
peer-to-peer, mesh
TRAFFIC TYPES
ZigBee/IEEE 802.15.4 addresses three typical
traffic types. IEEE 802.15.4 MAC can
accommodate all the types.
1. Data is periodic. The application dictates the
rate, and the sensor activates, checks for data and
deactivates.
2. Data is intermittent. The application, or other
stimulus, determines the rate, as in the case of say
smoke detectors. The device needs to connect to the
network only when communication is necessitated.
This type enables optimum saving on energy.
3. Data is repetitive, and the rate is fixed a priori.
Depending on allotted time slots, called GTS
(guaranteed time slot), devices operate for fixed
durations.
ZigBee employs either of two modes, beacon or
non-beacon to enable the to-and-fro data traffic.
Beacon mode is used when the coordinator runs on
batteries and thus offers maximum power savings,
whereas the non-beacon mode finds favour when
the coordinator is mains-powered.