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Mesh Network

The Walker Wireless System communicates using a ZigBee mesh network. This type of network allows data to automatically pass from node to node (device to device, i.e. thermostat, sensor etc…) wirelessly which allows these networks to cover large areas.

Another benefit of the ZigBee mesh network is that if a device loses its signal and can no longer transmit data through its current RF pathway, it will reroute its data to reach its destination through another RF pathway to reach its destination.

Each ZigBee Mesh network is capable of handling hundreds of nodes (devices). Walker Wireless is capable of running numerous mesh networks simultaneously, allowing for control of thousands of nodes (devices) in one system. The Walker Wireless mesh network solution applied in commercial buildings based on zone capacity and accuracy, is of a caliber unlike anything else in the HVAC industry.


Walker Wireless System Topography : Zigbee Mesh Network

Zigbee Mesh Network
• Full RF redundancy, with multiple data paths
• Self-configuring / Self-healing
• Distributed intelligence



Technical Information and System Structure

About the Walker Wireless System

A ZigBee mesh network contains only 3 types of devices as described below.

Coordinator
A coordinator forms the network as devices are added and sets the communication channel and Operational PAN ID. There is only one coordinator per network. With coordinator firmware programmed into its wireless module (radio), a WZ_Zcoord always acts as the coordinator in a Walker Wireless system.

Routers
Routers expand the range of the ZigBee mesh network by creating a stepping stone to relay data between two devices that are out of range from each other, e.g. the more routers the more area can be covered. Routers are constantly powered and are able to send and receive data themselves as well as pass data to and from other devices.
Every Walker Wireless product except the Battery-SENSOR acts as a router, including any Zcoord in the system other then the one setup as a coordinator.

End Devices
End Devices transmit their data and then hibernate for a set amount of time. Because End Devices hibernate, they are unable to pass data to and from other devices and therefore unable to expand the range of the ZigBee mesh network.
The Battery-SENSOR is the only End Device Walker Wireless offers and can communicate to a Zcoord or directly to another thermostat.

The location of each device in the building does not matter as long as the device is in the ZigBee mesh network. Typically when installing the Walker Wireless system all SACs and Zcoords will be installed in a mechanical room centrally located in the network

Hover over to view system details:
Currently the Walker Wireless System can have 20 devices (Address 3-22) per SAC/Zcoord pair and up to 300 devices per network. If more devices are needed 2 or more networks can be made with each network having 300 devices each, Allowing the system to control thousands of zones simultaneously. Data will not be transmitted wirelessly between 300 device networks, data transferred between these networks must be done by Walker Smart-LAN Highway.

Network Details

The Walker Wireless System uses the wireless ZigBee mesh network protocol for communication. ZigBee is a communication protocol based on the IEEE 802.15.4 PHY/MAC to provide reliable data transfer in noisy, interference-rich environments. ZigBee layers on top of 802.15.4 with Mesh Networking, Security, and Applications control.

The ZigBee mesh network allows for large wireless networks to be created over vast areas. The radios installed in all Walker Wireless products allow for up to 30 meters (unobstructed) between devices. In testing, the radios freely communicate 20 meters between radios on the same floor and 6 meters (2 floors) vertically in a concrete/steel building.

Because ZigBee is a mesh network, every device is connected to all surrounding devices wirelessly. When data is transmitted the ZigBee mesh network will find the best route for the data to travel. If for any reason preferred route becomes unavailable (E.g. device is not powdered, strong interference, etc…) the ZigBee mesh network will find a new route for the data by relaying it through other pathways.

For more information please contact sales@walkersys.com
   

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