Wireless Communications and Mesh Networks

Wireless networks are all around us—in our cell phones, laptops, cars, televisions—and now, in our lighting, with reliable “mesh” networking based on the open ZigBee® standard. Wireless networks consist of interconnected devices that all use the same wireless protocol to communicate. Each device—in the case of lighting, this can include luminaires, switches, sensors and more—contains a small radio transmitter, which can be either built into the device or fitted externally.

The wireless networks that most of us are familiar with connect a transmitting device directly with a receiving device. In a wireless mesh network, by contrast, each device can communicate with every other device, and can relay messages for its neighbors. Data is passed from device to device using the most reliable communication links and the most efficient path until the destination is reached. Communication is two-way, which helps to increase reliability by allowing devices to acknowledge receipt of data and to require retransmission of data not received. 

Mesh networks are self-healing, in that if any disruption occurs (such as a device failing or being removed), data is automatically re-routed. The built-in redundancy of having multiple pathways available helps to make the mesh network both robust and reliable. Mesh networks are also highly scalable, in that you can extend the network simply by adding more devices. The network's self-configuring capabilities identify when a device is added: working out what type of device it is, where its neighbors are, and what the best path is through the network.

Wireless mesh for lighting control

Wireless mesh networks provide many benefits for lighting control, including flexibility, reliability. and reduced installation costs. Some of the most important features of wireless mesh networking include the following: 

• Low Cost: Installation and ongoing management costs are greatly reduced without the need to run control wires from each device back to the network's central controller. Although wireless sensors and control devices may have been more expensive than their wired counterparts in the past, the inclusion of open-standard ZigBee radios is minimizing any cost differential. 

• Low Complexity: Wireless allows users to avoid the complexity of connecting wires from hundreds (or thousands) of devices back to a single controller. In addition, wireless lighting control solutions can provide tools to automate complex tasks such as commissioning.

• Scalability: Wireless mesh solutions can support more devices over greater distances per controller than wired ones, which makes wireless ideal for multi-room and multi-floor installations. The nature of mesh networks means that simply adding new devices can extend the communication coverage of the network. And because devices are wireless, they can be placed in areas that were previously difficult, costly, or even impossible to access.

• Reliability: Both wired and wireless networks use mature technologies that offer great robustness and reliability. Wireless mesh networks like ZigBee add reliability by offering multiple communication routes for any message, rerouting messages if a device fails to ensure that all messages are received, and automatically switching to a new channel if wireless interference is detected. 

• Flexibility: Flexibility is one of the biggest benefits of wireless. Devices can be installed where they will provide maximum benefit instead of where it is easiest to run control wires. Devices are also grouped into "zones" using software rather than hard wiring, which allows changes to be made at any time through simple software reconfiguration (no costly or disruptive rewiring required).

• Bi-directional: Bi-directional communications enables the capture and delivery of critical energy usage data. This allows measurement and verification of energy use, as well as advanced energy management applications.

The ZigBee Alliance is a long-standing organization of leading manufacturers producing interoperable wireless products using the open-standard ZigBee communications protocol. ZigBee wireless communications (based on IEEE 802.15.4) use mesh networking, and are commonly used around the world.

Mesh networking was not created specifically for wireless. This network topology has been hard at work for many years in both the public switched telephone network (PSTN) and the Internet. The mesh is the best way to achieve the resiliency and scalability demanded for these mission-critical public networks.

Find out more

• What's so good about mesh networks?  
• What is wireless lighting control?
• Lighting resources