Over the past few years, we have moved from disconnected systems into a world completely linked to each other all in control of our fingertip. Smart home devices and similar technologies have augmented over the years. What once started with automation has now expanded into the Internet of Things(IoT). This in turn has settled into a more amiable category we call smart homes.
The whole point of a smart home is to have everything connected to literally everything. In particular, all the connected devices can share information with each other. You can control all of them without the need to visit each thing individually. All the devices, manufactured by different companies are connected over a single network. Therefore, requires a common language for its communication. That’s where ZigBee shows in!
What is ZigBee?
ZigBee is a wireless technology standard that provides a set of communication protocols for short-range communications. It is an open-source global standard developed by Zigbee Alliance to address the needs of low-cost, low power wireless IoT networks. The protocol is used in low data rate, short to medium range wireless networking devices like senors and control networks.
ZigBee provides flexibility for developers and end-users and delivers great interoperability. Because of its important feature of being low-cost, low-power consumption and having faster wireless connectivity, the protocol has many applications. For instance, its a popular technology for smart home, because it outstands other wireless technologies with some distinct features. Firstly, communication is two -way which makes ZigBee devices reliable. Secondly, it caters to all sectors like lightings, security, appliances and home access. Thirdly, and most importantly, this technology requires very little power mainly due to its low latency and low duty cycle. In addition, it uses mesh network and thus reduce chances of failure at nodes.
ZigBee offers a wireless range of 70m indoors and 400m outdoors. It supports multiple networks like point to point, point to multipoint mesh- networks. Notably, it uses AES 128 encryption thus protecting your information while on air transfers. In addition, its easy installation and maintenance makes it more affordable.
Here’s an interesting fact on the origin of the name ZigBee! The name is closely in relation with Bees because they do ‘waggle dance’ to communicate with each other when they return to their hives. This zigzag dance is where ZigBee got its name.
ZigBee Frequency
Zigbee uses physical and MAC layers of the IEEE 802.15.4 specification. In addition, it operates in an unlicensed 2.4 GHz ISM band. Although 2.4 GHz is pervasive worldwide, there are devices that use frequency bands like 915 MHz, 868 MHz, and 784 MHz in USA, Europe, and China respectively. Also, it transfers data at a rate of 250 kbps.
ZigBee vs Wi-Fi
Wondering why ZigBee when you already have other communication standards like Wi-Fi, Bluetooth? As Wi-Fi and Bluetooth, ZigBee is used for short-range communications or to establish a personal area network and works on the same band as Wi-Fi and Bluetooth. It is specially built for control and sensor networks. It is mainly used to monitor and control devices of which both Wi-Fi and Bluetooth are not quite suitable for this specific application of wireless communication.
Mainly, ZigBee is based on IEEE 802.15.4 whereas Wi-Fi is dependent on IEEE 802.11 series. Both are different technologies because ZigBee uses WPAN while Wi-Fi is WLAN based. Wi-Fi covers a distance of 30-100 meters but the other is used to get a range of 10-30meters. Also, it provides a data rate of 250 Kbps. On the other hand, devices operating with high power and high data rate uses Wi-Fi technology for communication as it works at a rate of 54 Mbps. Zigbee’s best quality is its low power consumption rate and sustained battery life of the devices.
ZigBee vs Bluetooth
ZigBee when compared with Bluetooth, uses a transmit power of the only 100mW which makes it efficient in case of power consumption. In addition, it is designed to support hundreds of devices which is a vantage over Bluetooth that supports a maximum of 7 devices. Now you know the substantive use of ZigBee! Here’s a table highlighting the differences.
System Structure
ZigBee system consists of ZigBee Co-ordinator, Router and End device.
- ZigBee Coordinator (ZC): A network consists of at least one central unit. ZC is the most important device as it coordinates and acts as a bridge of network. It is the device responsible for the start of the network. Most importantly, this unit is responsible for the transmission and reception of data. It also facilitates the handling and storing of information.
- ZigBee Router (ZR): A router is an intermediate unit. It allows data to pass through them to and fro to other devices.
- ZigBee End-Device (ZED): A ZED interfaces to a sensor and executes the control operation. The end device contains just enough functionality to talk to either the coordinator or the router. This causes the node to stay asleep for a long time thereby increasing battery life to a great extent. A ZED device requires less energy as compared to the ZC or ZR.
Topologies
The number of coordinators, routers, devices in the network depends on the topology used. There are three ZigBee Network topologies: star, Cluster tree and Mesh.
- A star network consists of a coordinator and any number of end devices. These devices are then connected to the coordinator but isolated from each other.
- In Cluster Tree topology, end devices connect the coordinator via Router.
- In the mesh networks, the nodes are interconnected with other nodes so that there exist multiple pathways connecting each node. The connection between nodes is updated using built-in routing methodologies. Thus, it provides good stability in changing conditions or failure at any node.
ZigBee Architecture
There are four layers in ZigBee network architecture. ZigBee protocol architecture consists of a stack of various layers of which physical and MAC layers are as defined in IEEE 802.15.4 and the other two layers belong to Zigbee specification.
- The Physical layer performs modulation and demodulation to the signals send and received.
- MAC layer transfer data using CSMA/CA. Moreover, the MAC layer synchronizes the communication between the devices.
- The network layer is responsible for setting up a network, connecting to the devices, routing data, etc.
- Lastly, the application layer allows the device to interface with a network layer for data management and communication between the devices.
What devices use ZigBee?
Now you know what ZigBee is, it’s important to know the devices that work with it. The ZigBee Alliance industry consists of companies using this protocol. Currently, there are more than 400 members registered in the Alliance and over 2,500 devices in use. Here are some users of this standard:
- Amazon Echo Plus
- Samsung SmartThings
- Apple
- Comcast
- Honeywell
- Philips
- Bosch
- Nokia
You can get a full list of members of the ZigBee alliance.
ZigBee Applications
ZigBee enables a wide usage in wireless networks with low- cost, low-power solutions. Most importantly, it provides the ability to run for years on inexpensive batteries to monitor and control applications. Generally, home automation, Healthcare, Material tracking are some of the areas where ZigBee is making its advancements. Some of its applications include:
- Home Automation including security systems, meter reading systems, Light control systems
- consumer electronics including Gaming consoles, wireless remote controls.
- Industrial Automation systems as in asset management, personnel tracking, livestock management.
- Healthcare, the patient wears a ZigBee device, which periodically collects patients metrics and sends to the hospital for analysis.
- Building’s structural health monitoring. It is useful in earthquake-prone areas. Sensors installed throughout the building sends data to detect signs of damage.
- Grid monitoring involving temperature monitoring, power management, fault locating etc.
- Smart metering to prevent theft, pricing support etc
