Wireless 101: Mesh Networking
Wireless networks are all around us—in our cell phones, laptops, cars, televisions—and now, in our buildings. The use of wireless networks for building energy management has many benefits. By eliminating the need for dedicated control wiring and related conduit and containment material and installation costs are dramatically reduced. Wireless is the ideal approach for retrofitting existing buildings and connecting new buildings where a lack of cable pathways is an issue or impediment.
Wireless networks consist of interconnected devices that all use the same wireless protocol to communicate information. Each device in the building—a luminaire, a switch, a sensor, a thermostat, a wall outlet device and more—contains a small radio transmitter. The wireless networks that most of us are familiar with connect a transmitting device directly with a receiving device using point-to-point technology.
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 any 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.
Daintree ControlScope’s wireless mesh networking technology is based on the ZigBee standard. ZigBee wireless communications (based on the IEEE 802.15.4) are commonly used around the world across a dozen applications including retail automation, home automation, building automation, and healthcare. ZigBee uses 128 bit symmetric encryption keys to secure communications between the devices within the mesh network.
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.
Wireless mesh benefits for building energy management
Some of the most highly efficient buildings using wireless mesh networking benefit from:
- 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.
- Simplicity: Wireless allows users to avoid the complexity of connecting wires from hundreds (or thousands) of devices back to a single controller. In addition, wireless building energy management solutions can provide tools to automate complex tasks such as commissioning.
- 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. Using Daintree’s ControlScope software, the devices can be grouped into “zones” rather than hard wiring, which allows changes to be made at any time through simple software reconfigurations (no costly or disruptive rewiring required). And because devices are wireless, they can be placed in areas that were previously difficult, costly, or even impossible to access.
- 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.
- 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.
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