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Third Year Seminar Report
Ruchita Jadhav T.E. Roll No.: 33 Year: (2009-2010)
Guide Prof .Mrs.P.D.Bhamre
Co-Guide Prof. V.S.Bharambe
Department of Information Technology
K.K.Wagh Institute of Engineering Education and Research
Zigbee is a new Wireless sensor network technology characteristic of less distance and low speed. It can be used in some special situation for signal collection, processing and trans-mitting.ZigBee is a technology now being deployed for wireless sensor networks. A sensor network is an infrastructure comprised of sensing, computing and communications elements that allows the administrator to instrument, observe and react to events and phenomena in a specified environment.Typical applications include, but are not limited to, data collection, monitoring, surveillance and medical telemetry.
ZigBee is the set of specifications built around the IEEE 802.15.4 wireless protocol. ZigBee technology is a low data rate, low power consumption, low cost, wireless networking protocol targeted towards automation and remote control applications
ZigBee is a communication protocol that uses small, low-power digital radio signals based on the IEEE 802.15.4 standard.ZigBee operates in
ISM radio bands: In USA 915 MHz, in Europe 868 MHz and 2.4 GHz in other parts of the globe. In the 2.4 GHz band there are 16 ZigBee channels, with each channel requiring 2 MHz of bandwidth.
The most capable ZigBee node type is said to require only about 10typical Bluetooth or Wireless Internet node, while the simplest nodes are about 2However, actual code sizes are much higher, closer to 50transmission range of Zigbee is over 50 meters and speed is 20-250KB/s, it needs only 32K of system resources. It is simple, effective and cheaper than other WPANs like bluetooth, WiFi. ZigBee solves the needs of remote monitoring and control, and sensor network applications. It takes full advantage of a powerful physical radio specified by IEEE802.15.4, adding logical network, security and application software to the specification.
1.1 What is Zigbee?
Zigbee is a Technological Standard Created for Control and Sensor Networks based on the IEEE 802.15.4 specification for wireless personal area network .It is a New wireless technology that has application in various fields.Zigbee benfits are low cost and Range and obstruction issues avoidance.The main features of this standard are network flexibility, low cost, very low power consumption, and low data rate in an adhoc self-organizing network among inexpensive fixed, portable and moving devices.
1.2 Origin of word Zigbee
The erratic, zig-zagging patterns of bees between flowers while collecting pollens from the flowers Symbolizes communication between nodes in a mesh network of Zigbee network.The network components are analogous to queen bee, drones, worker bees.
Process on ZigBee-style networks began in 1998, when many engineers realized that both WiFi and Bluetooth were going to be unsuitable for many applications. In particular, a need for self-organizing ad-hoc digital radio networks arose.
ZigBee is very low cost, low power consumption, two ways, wireless communication proÃ‚Â¬tocol. It adopts IEEE 802.15.4, as its lower protocol layers: the physical layer (PHY) and medium Access Control (MAC) portion of data link layer (DLL) takes care of network, secuÃ‚Â¬rity and upper application issues. The relative organization of the IEEE radio with respect to the ZigBee functionality. Wireless systems mostly use cell phone-style radio links, using point-to-point or point-to- multipoint transmission. These traditional wireless formats have drawbacks like rigid structure, signal dropping and meticulous planning requirements.
1.3 Zigbee Alliance
It is association of companies working together to enable reliable ,cost effective, low power ,wirelessly networked ,monitoring and control products based on an open global standard.
1.4 Need of Zigbee
ZigBee was created to satisfy the market's need of a standards-based wireless network that is cost-effective,supports low data rates,low power consumption,secure and reliable.
Why ZigBee? Let us compare it to its closest competitor, Bluetooth. If we want to build a remote battery powered Bluetooth node, we need at least 250K of memory for the code and stack, and transmission speed of 720KB/s up to range of approximately 10 meters , if there are no cordless phones, VCRs etc around. The battery life will be 7 days. Now, compare that to
ZigBee. Though it is a lower-speed wireless protocol that's targeted at transmission speeds of 20-250KB/s, it has a transmission range of over 50 meters. Battery life is 2 years and 32K of system resources is required. This is simple, effective, and very practica
ZigBee is the only wireless standards-based technology that addresses the unique needs of remote monitoring control, and sensory network applications,enables broad-based deployÃ‚Â¬ment of wireless networks with low cost, low power solutions.
1.5 Wireless sensor networking is one of the most ex-
citing technology markets today
. They say that over the next five to ten years, wireless sensors will have a significant impact on almost all major industries as well as our home lives. Broadly, this technology market includes application segments such as automated meter reading, home automation, building automation, container security/tracking, and many others.
Although products that span these application segments are diverse and different in how they operate and what they do, their requirements from a wireless communication technology are very similar. For example, these applications generally require low data rates and are battery powered.
The main motivations for migrating these products to wireless communications are threeÃ‚Â¬fold:
1. Installation cost - The cost of running wires in a typical building automation project in an existing facility can be as high as 80project cost . 2. Maintenance - It is easier to configure a hot-water heater controller with a hand-held remote than a keypad in the closet. 3. New markets - Eliminating the wire opens new markets that were previously unavailable to wired products.
Zigbee [3, 5] was introduced as an alternative to Bluetooth for devices with low power consumption requirements and applications of lower bit rates. Although products based on the Bluetooth standard are often capable of operating at greater distances, the targeted operational area is the one around an individual, (e.g. within a 10 meters diameter). BlueÃ‚Â¬tooth utilizes a short range radio link that operates in the 2.4 GHz industrial scientific and medical (ISM) band similar to WLAN. However, the radio link in Bluetooth is based on frequency hop spread spectrum. Although at any point in time, the Bluetooth signal ocÃ‚Â¬cupies only 1MHz, the signal changes the center frequency (or hops) deterministically at a rate of 1600Hz. Bluetooth hops over 79 center frequencies, so over time the Bluetooth signal actually occupies 79MHz. The new short range, low power, low rate wireless networking protocol, Zigbee, complements the high data rate technologies such as WLAN and open the door for many new applications. This standard operates at three bands, the 2.4 GHz band with a maximum rate of 250 kbps, the 915 MHz band with a data rate of 40 kbps, and the 868 MHz band with a data rate of 20 kbps. While Bluetooth devices are better suited for fairly high rate sensor and voice applications, Zigbee is better suited for low rate sensors and devices used for control applications that do not require high data rate but must have long battery life, low user interventions and mobile topology. Some of these applications are in the fields of medicine
ZigBee is a low-cost, low-power, wireless mesh networking proprietary standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applicaÃ‚Â¬tions, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range. The ZigBee Alliance, the standards body that 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 1.0/2.0 Commercial Building Automation Telecommunication Applications Personal, Home, and Hospital Care Toys
The relationship between IEEE 802.15.4 and ZigBee is similar to that between IEEE 802.11 and the Wi-Fi Alliance. The ZigBee 1.0 specification was ratified on 14 December 2004 and is available to members of the ZigBee Alliance. Most recently, the ZigBee 2007 specification was posted on 30 October 2007. The first ZigBee Application Profile, Home Automation, was announced 2 November 2007. As amended by NIST, the Smart Energy Profile 2.0 specification will remove the dependency on IEEE 802.15.4. Device manufacturÃ‚Â¬ers will be able to implement any MAC/PHY, such as IEEE 802.15.4(x) and IEEE P1901, under an IP layer based on 6LowPAN.
ZigBee operates in the industrial, scientific and medical (ISM) radio bands; 868 MHz in Europe, 915 MHz in the USA and Australia, and 2.4 GHz in most jurisdictions worldwide. The technology is intended to be simpler and less expensive than other WPANs such as Bluetooth. ZigBee chip vendors typically sell integrated radios and microcontrollers with between 60K and 128K flash memory, such as the Jennic JN5148, the Freescale MC13213, the Ember EM250, the Texas Instruments CC2430, the Samsung Electro-Mechanics ZBS240 and the Atmel ATmega128RFA1. Radios are also available stand-alone to be used with any processor or microcontroller. Generally, the chip vendors also offer the ZigBee software stack, although independent ones are also available. Because ZigBee can activate (go from sleep to active mode) in 15 msec or less, the latency can be very low and devices can be very responsive particularly compared to Bluetooth wake-up delays, which are typically around three seconds.  Because ZigBees can sleep most of the time, average power consumption can be very low, resulting in long battery life. The first stack release is now called ZigBee 2004. The second stack release is called ZigBee 2006, and mainly replaces the MSG/KVP structure used in 2004 with a "cluster library". The 2004 stack is now more or less obso-lete. ZigBee 2007, now the current stack release, contains two stack profiles, stack profile 1 (simply called ZigBee), for home and light commercial use, and stack profile 2 (called ZigBee Pro). ZigBee Pro offers more features, such as multi-casting, many-to-one routing and high security with Symmetric-Key Key Exchange (SKKE), while ZigBee (stack profile 1) offers a smaller footprint in RAM and flash. Both offer full mesh networking and work with all ZigBee application profiles. ZigBee 2007 is fully backward compatible with ZigBee 2006 devices: A ZigBee 2007 device may join and operate on a ZigÃ‚Â¬Bee 2006 network and vice versa. Due to differences in routing options, ZigBee Pro devices must become non-routing ZigBee End-Devices (ZEDs) on a ZigBee 2006 or ZigBee 2007 network, the same as ZigBee 2006 or ZigBee 2007 devices must become ZEDs on a ZigBee Pro network. The applications running on those devices work the same, regardless of the stack profile beneath them.
ZigBee protocols are intended for use in embedded applications requiring low data rates and low power consumption. ZigBee's current focus is to define a general-purpose, inexpensive, self-organizing mesh network that can be used for industrial control, embedded sensing, medÃ‚Â¬ical data collection, smoke and intruder warning, building automation, home automation, etc. The resulting network will use very small amounts of power individual devices must have a battery life of at least two years to pass ZigBee certification.
Typical application areas include Home Entertainment and Control Smart lighting, advanced temperature control, safety and security, movies and music
Home Awareness Water sensors, power sensors, energy monitoring, smoke and fire detectors, smart appliances and access sensors
Mobile Services m-payment, m-monitoring and control, m-security and access control, m-healthcare and tele-assist
Commercial Building Energy monitoring, HVAC, lighting, access control
Industrial Plant Process control, asset management, environmental management, energy
management, industrial device control
1.7 Software and hardware
The software is designed to be easy to develop on small, inexpensive microprocessors. The radio design used by ZigBee has been carefully optimized for low cost in large scale producÃ‚Â¬tion. It has few analog stages and uses digital circuits wherever possible. Even though the radios themselves are inexpensive, the ZigBee Qualification Process involves a full validation of the requirements of the physical layer. This amount of concern about the Physical Layer has multiple benefits, since all radios derived from that semiconductor mask set would enjoy the same RF characteristics. On the other hand, an uncertified physical layer that malfunctions could cripple the battery lifespan of other devices on a ZigBee netÃ‚Â¬work. Where other protocols can mask poor sensitivity or other esoteric problems in a fade compensation response, ZigBee radios have very tight engineering constraints: they are both power and bandwidth constrained. Thus, radios are tested to the ISO 17025 standard with guidance given by Clause 6 of the 802.15.4-2006 Standard. Most vendors plan to integrate the radio and microcontroller onto a single chip.
Protocol stack for Zigbee
Zigbee protocol stack mainly consists of PHY and MAC layer from IEEE 802.15.4 stan-dard,Network layer,Application layer.?
2.1 PHYSICAL layer
ZigBee operates in one of three license free bands 2.4 GHz, 915 MHz for North America, and 868 MHz for Europe.At 2.4 GHZ, there are a total of 16 channels available with a maximum data transfer of 250 kbps.At 915 MHz: 10 channels for a max 40 kbps transfer rate.At 868 MHz: 1 channel for a max 20 kbps transfer rate.
2.1.1 Features of PHY layer:
1. Activation and deactivation of the radio transceiver.
2. energy detection -Here the power of received signal is estimated within bandwidth of channel .It is used in network layer for channel selection.
3. Link quality indication (LQI)-This indicator shows the quality of the link between devices within a Zigbee.It is characterization of strength or quality of received packet.
4. Clear channel assessment (CCA)-It is performed to detect if the channel is busy is or empty.A mode in CCA performs the RF energy detection with other wireless network is avoided.
5. Channel selection.
2.2 MAC layer
Mac layer control access to the radio channel.Its responsibilities are transmitting beacon frames,synchroinisation and providing a reliable transmission.
2.2.1 Different mac layer devices
1. Full function device(FFD):
A network device that extends network area coverage, dynamically routes around obÃ‚Â¬stacles ,and provides backup routes in case of network congestion or device.
2. Reduced function device(RFD)
A network device that can start or receive a message but cannot forward messages upstream or downstream.It can communicate with the co-ordinator or a router,but not directely with other end devices.
3. PAN co-ordinator
It is controller of a network that is responsible for the network formation and main-tanance.The PAN co-ordinator must be a router.
4. MAC Layer association
On the power on of end device it sends beacon request.Beacon is a transmission by a Zigbee router to confirm their presence o other network devices.PAN coordinator sends the beacon.Then end device requests for the association.PAN co-ordinator checks wheather enough resourses are present or not if present it sends acknowledgement.and association is established between PAN co-ordinator and end device.
2.3 Network Layer
1. Discovery of route and maintenance.
2. Routing of message
3. Clear channel assessment (CCA)-It is performed to detect if the channel is busy is or empty.A mode in CCA performs the RF energy detection with other wireless network
is avoided. 4. Network management and addressing.
2.3.1 Network layer topologies
Zigbee can work in 3 topologies
1. Mesh topology
2. Cluster tree topology
3. Star topology
2.3.2 Mesh topology in Zigbee
coordinator ro Titer end devices
Figure 2.3: Mesh Topology
Mesh topology,also called peer-to-peer, consists of a mesh of interconnected routers and end. Each router is typically connected through atleast two pathways, and can relay messages for its neighbors.Mesh topology supports "multi-hop"communications, through which data is passed by hopping from device to device using the most reliable communication links and most cost-effective pathuntil its destination is reached.The multi-hop ability also helps to provide fault tolerance, in that if one device fails or experiences interference, the network can reroute itself using the remaining devices.
2.4 Benefits of Mesh topology
1. This topology is highly reliable and robust.Should any individual router become inacÃ‚Â¬cessible, alternative routes can be discovered and used.
2. The use of intermediary devices in relaying data means that the range of the network can be significantly increased, making this topology highly scalable.
3. Weak signals and dead zones can be eliminated by simply adding more routers to the network.
2.5 Limitations of Mesh topology
1. This topology has a higher communications overhead than the star topology, which can result in increased latency and lower end-to-end performance.
2. Meshed routing requires more complex network protocols. This means the routers require more embedded resources, which can result in
3. increased power consumption and costs.
2.6 The power of Mesh Topology
Mesh networking was not created specifically for wireless sensor networks. This network topology is already hard at work in both the public switched telephone network (PSTN) and the Internet. The mesh is the best way to achieve the resiliency and scalability demanded from these mission-critical public networks.Examining the key benefits that mesh topologies provide in a bit more detail will help to explain why it is such an appropriate choice for many wireless sensor networks.
2.7 Cluster tree topology in Zigbee
The cluster tree topology is less efficient than the other two, and is therefore rarely (if ever) implemented.
2.8 Star topology in Zigbee
In a Star topology, also called point-to-point, all devices are within direct communication range to the coordinator, through which all messages are routed.A device sends a message to the coordinator, which then passes it on to the destination device. Direct communication
Figure 2.4: Star Topology between the end devices is not supported.
2.9 Benefits of Star topology
1. Its simplicity means that this topology does not require a complex network layer or routing protocols
2. Performance is generally high, with packets taking a maximum of two hops to reach their destination.
2.10 limitation of Star topology
1. )There are no alternative paths between the device and coordinator, so if a path beÃ‚Â¬comes obstructed, communication is lost between the device and coordinator
2. )The radius of the network is limited by the radio range between the coordinator and child devices (typically 30-100 meters).
2.11 Application layer
Application layer mainly consists of Application support sublayer,Application framework and Zigbee device objects
Application Support sublayer-The portion of the Application Layer responsible for proÃ‚Â¬viding a data service to the application and ZigBee device profiles. In addition, it provides a management service to maintain binding links and the storage of the binding table itself.
Application framework-The portion of the Application Layer that provides a description of how to build a profile onto the ZigBee stack so that profiles can be generated in a consistent manner. It also specifies a range of standard data types for profiles, descriptors to assist in service discovery, frame formats for transporting data, and a key value pair construct to rapidly develop simple, attribute based profiles.
Zigbee device objects-The portion of the ZigBee Application Layer responsible for definÃ‚Â¬ing the role of the device within the network (e.g. coordinator, router, or end device), initiating and/or responding to binding and discovery requests, and establishing a secure relationship between network devices. It also provides a rich set of management commands, defined in the ZigBee Device Profile (ZDP).
2.12 Reliable ZigBee Networks
ZigBee is a broad-based standard that is intended to cover a range of applications and competing requirements. Figure 1 shows an example of the range of target markets typically discussed for ZigBee.
2.13 Security in Zigbee
ZigBee security, which is based on a 128-bit AES algorithm, adds to the security model provided by IEEE 802.15.4. ZigBee's security services include methods for key establishment and transport, device management, and frame protection.The ZigBee specification defines security for the MAC, NWK and APS layers. Security for applications is typically provided through Application Profiles.
2.13.1 Trust center
The Trust Center decides whether to allow or disallow new devices into its network.The Trust Center may periodically update and switch to a new Network Key. It first broadcasts the new key encrypted with the old Network Key. Later, it tells all devices to switch to the new key. The Trust Center is usually the network coordinator, but is also able to be a dedicated device. It is responsible for the following security roles:
1. Trust Manager, to authenticate devices that request to join the network
2. Network Manager, to maintain and distribute network keys
3. Configuration Manager, to enable end-to-end security between devices
2.13.2 Security keys
ZigBee uses three types of keys to manage security: Master, Network and Link.
2.13.3 Master keys
These optional keys are not used to encrypt frames. Instead, they are used as an initial shared secret between two devices when they perform the Key Establishment Procedure (SKKE) to generate Link Keys.Keys that originate from the Trust Center are called Trust Center Master Keys, while all other keys are called Application Layer Master Keys.
2.13.4 Network keys
These keys perform security Network Layer security on a ZigBee network. All devices on a ZigBee network share the same key.High Security Network Keys must always be sent enÃ‚Â¬crypted over the air, while Standard Security Network Keys can be sent either encrypted or unencrypted. Note that High Security is supported only for ZigBee.
2.13.5 Link keys
These optional keys secure unicast messages between two devices at the Application Layer.Keys that originate from the Trust Center are called Trust Center Link Keys, while all other keys are called Application Layer Link Keys.
2.14 Security modes
ZigBee offers two different security modes: Standard and High.
2.14.1 Standard security mode
In Standard Security mode, the list of devices, master keys, link keys and network keys can be maintained by either the Trust Center or by the devices themselves. The Trust Center is still responsible for maintaining a standard network key and it controls policies of network admittance. In this mode, the memory requirements for the Trust Center are far less than they are for High Security mode.
2.14.2 High security mode
In High Security mode, the Trust Center maintains a list of devices, master keys, link keys and network keys that it needs to control and enforce the policies of network key updates and network admittance. As the number of devices in the network grows, so too does the memory required for the Trust Center.
The additional security capabilities inherent in ZigBee PRO are critical as ZigBee is used in increasingly important applications. The control of critical systems infrastructure, whether in a commercial building, utility grid, industrial plant, or a home security system must not be compromised. ?
2.14.3 Difference between Zigbee and Bluetooth
Bluetooth and ZigBee have much in common. Both are types of IEEE 802.15 wireless personal-area networks," or WPANs. Both run in the 2.4-GHz unlicensed frequency band, and both use small form factors and low .
Zigbee - Protocol,Devices and Applications
The protocols are built on recent algorithmic research to construct a low-speed ad-hoc netÃ‚Â¬work of nodes automatically. In large network instances, the network will be a cluster of clusters in the form of a mesh or a single cluster. ZigBee protocols minimize the time for which the radio is on to reduce the power use. The current profiles derived from the ZigBee protocols support beacon and non-beacon enabled networks.
In beacon enabled networks, the special network nodes called ZigBee Routers transmit periodic beacons to confirm their presence to other network nodes. Beacon Oriented netÃ‚Â¬works use Guaranteed Time Slots (GTS). Nodes are active only when a beacon is being transmitted.They may sleep between beacons, that will lower the duty cycle and increase the battery life.The intervals may range from 15.36 milliseconds to
3.2 What ZigBee's "Low Power Consumption" Means
ZigBee's low power consumption is rooted not in RF power, but in a sleep mode specifically designed to accommodate battery powered devices. Any ZigBee-compliant radio can switch automatically to sleep mode when it's not transmitting, and remain asleep until it needs to communicate again. For radios connected to battery-powered devices, this results in exÃ‚Â¬tremely low duty cycles and very low average power consumption.
When a radio is in sleep mode, its RF power rating is irrelevant; it's only when transmitÃ‚Â¬ting that its RF power affects power consumption. In the case of Cirronet's ZigBee solutions, a radio with 100 mW RF power will typically consume 150 mA at 3.3 V when transmitting,
compared to 75 mA at 3.3 V for a radio with 1 mW RF power. The 100 mW radio consumes twice as much power - but only when actively transmitting. As long as the high power radio's low noise amplifier is turned off, power consumption while sleeping is roughly equivalent to that of a low power radio.
If the high RF power radio is awake and transmitting 5very active radio, the extra average power consumption is roughly 5power consumption means that a battery that would last for five years with a 1 mW radio would last four years and nine months with a 100 mW radio. As this illustrates, ZigBee radios with higher RF output ratings are still excellent candidates for use with battery powered devices.
It's important to note that the ZigBee Alliance doesn't itself specify anything for RF power. ZigBee's RF power specification comes from IEEE 802.15.4, which specifies a minÃ‚Â¬imum power output rating of 1 mW, with no specified maximum. The de facto 100 mW "high power" level relates to the European limit of 100 mW EIRP, including antenna gain.
There are three different types of ZigBee device:
1. ZigBee coordinator (ZC): The most capable device, the coordinator forms the root of the network tree and might bridge to other networks. There is exactly one ZigBee coÃ‚Â¬ordinator in each network. It is able to store information about the network, including acting as the repository for security keys.
2. ZigBee Router (ZR): Routers can act as an intermediate router, passing data from other devices.
3. ZigBee End Device (ZED): Contains just enough functionality to talk to its parent node (either the coordinator or a router); it cannot relay data from other devices.
1. ZigBee's main advantage is its ability to be configured in so-called mesh networks with wireless nodes that are capable of multi-year battery lives.
2. Zigbee Supports large no of nodes in network.
3. Zigbee has Low latency period.It is around 30ms.
4. Power consumption in zigbee is very low as compared to other wireless sensor network technologes hence long battery life.
5. Low cost
6. It Can be used globally since Zigbee alliance is an open global standard source.
7. Zigbee network designs are simple.
1. It works over short range.
2. Data rate is low.
3.6 Applications of Zigbee
1. Home Automation-The ZigBee Home Automation profile is likely to be the first ZigBee application profile to hit the marketplace in volume and also holds promise to be the first application space where multiple products from multiple vendors are truly interÃ‚Â¬operable allowing users to mix and match products to enhance their digital lifestyle. Lighting control, thermostats, occupancy and motion sensors, security systems, door and window sensors, as well as fixed and mobile keypads all occupy the ZigBee home automation space and can be bound together to make sophisticated home automation behaviors.
2. Building automation-Wireless sensing and control mesh networks can make building automation easier and more efficient by combining lighting,HVAC, security, safety sysÃ‚Â¬tems, and other monitoring networks into a single platform.
3. Industrial plant monitoring-Wireless sensing and control mesh networks provide accuÃ‚Â¬rate and efficient IPM, and are also ideal to deploy in hazardous environments in which you want to minimize human exposure.
4. PC and peripherals-PC and peripherals like mouse,keyboard,joystic can be automated.
5. personel health care-Patient monitoring,remote diagnosis are incuded in personel health care applications.
Comparing ZigBee technology with the other present technology it is evident that ZigBee can have a safe future in this effervescent world of technology.There is definitely a place on the market for ZigBee, since no global standard exists today in the wireless sensor network
ZigBee is the specification of a low-cost, low-power wireless communications solution, meant to be integrated as the main building block of ubiquitous networks. It is maintained by the ZigBee Alliance, which develops the specification and certifies its proper implementation. As of 2007, the latest publicly available revision is the 2006 version.
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1 Introduction 1
1.1 What is Zigbee? 1
1.2 Origin of word Zigbee 1
1.3 Zigbee Alliance 2
1.4 Need of Zigbee 2
1.5 Wireless sensor networking is one of the most exciting technology markets today 2
1.6 Uses 4
1.7 Software and hardware 5
2 Protocol stack for Zigbee 6
2.1 PHYSICAL layer 7
2.1.1 Features of PHY layer: 7
2.2 MAC layer 7
2.2.1 Different mac layer devices 7
2.3 Network Layer 8
2.3.1 Network layer topologies 9
2.3.2 Mesh topology in Zigbee 9
2.4 Benefits of Mesh topology 10
2.5 Limitations of Mesh topology 10
2.6 The power of Mesh Topology 10
2.7 Cluster tree topology in Zigbee 10
2.8 Star topology in Zigbee 10
2.9 Benefits of Star topology 11
2.10 limitation of Star topology 11
2.11 Application layer 12
2.12 Reliable ZigBee Networks 12
2.13 Security in Zigbee 12
2.13.1 Trust center 12
2.13.2 Security keys 13
2.13.3 Master keys 13
2.13.4 Network keys 14
2.13.5 Link keys 14
2.14 Security modes 14
2.14.1 Standard security mode 14
2.14.2 High security mode 14
2.14.3 Difference between Zigbee and Bluetooth 14
3 Zigbee - Protocol,Devices and Applications 16
3.1 Protocol 16
3.2 What ZigBee's "Low Power Consumption" Means 16
3.3 Types 17
3.4 Advantages 17
3.5 Disadvantages 18
3.6 Applications of Zigbee 18
4 Conclusion 19
List of Figures
2.1 Zigbee protocol stack 6
2.2 Mac layer association 8
2.3 Mesh Topology 9
2.4 Star Topology 11
2.5 Network 13
List of Tables
2.1 Difference between Bluetooth and Zigbee 15