6
Network and IT Guidance Technical Guide
www.eaton.com/lightingsystems
Other Notes:
Radio:
2.4GHz
Standard:
IEEE 802.15.4
Transmitter Power:
+7dBm
Range
50m (150ft) LOS
# of Walls
2 interior walls standard construction
The wireless mesh network does not support integration with non-LumaWatt Pro wireless devices.
Coexisting with Wi-Fi
The LumaWatt Pro wireless network employs three techniques to either eliminate or drastically reduce its impact on Wi-Fi networks in the
building:
• Channel Selection: This technique involves identifying LumaWatt Pro wireless network IEEE 802.15.4 communication channels that do not
overlap with the current Wi-Fi deployment.
• Low Airtime Consumption: LumaWatt Pro is designed to reduce wireless communications during steady state operation, greatly reducing
the probability of collision with Wi-Fi traffic.
• Interference Tolerance: LumaWatt Pro is designed to work reliably despite encountering some interference, by detecting if communications
packets are lost and retransmitting if needed.
Channel Selection
LumaWatt Pro uses IEEE 802.15.4 channels, which are within the same 2.4 GHz frequency channel that IEEE 802.11 Wi-Fi operates within.
Since devices communicating on the same channel can cause interference, the devices need to be set on channels that do not overlap.
If we overlay the most frequently used channels used by IEEE 802.15.4 (LumaWatt Pro) and IEEE 802.11 (Wi-Fi) on the chart below, you can
see there is no overlap.
Wi-Fi uses channels 1, 6 and 11 by default, and IEEE 802.15.4 devices should be set to use channels 15, 20, 25 and 26 by default which
fall within the gaps of the Wi-Fi channels. For IEEE 802.15.4 channels 15 and 20 are typical and allow us to prevent overlap that can lead to
potential signal interference.
Ultimately this means that IEEE 802.11 Wi-Fi and IEEE 802.15.4 wireless devices can co-exist in the same space without interference if they
are properly set with the correct channels.
Low Airtime Consumption
LumaWatt Pro recognizes that it is not always possible to select non-overlapping channels. Many Wi-Fi access points aggressively use all
available spectrum to maximize performance. To coexist with such solutions, LumaWatt Pro is designed to send two messages every five
minutes per sensor. The following example shows the airtime consumption for a 50,000 square foot installation.
• Airtime Consumption = # sensors*msgs_per_sensor*airtime_per_msg/5mins*100%
• 50,000 square feet = 500 sensors
• 1.5 ms of airtime per message
• Airtime Consumption = 500 * 2 * 1.5ms/5mins * 100%
• Typical Airtime Consumption = 0.5%
