Since RSSI information does not pertain to any specific link with another device, the measured signal energy at a given frequency can come from any transmitter or device causing interference on that frequency, whether it is another nearby node on the same network, a device from a different PAN (Personal Area Network) on the same channel, or a non-ZigBee, non-802.15.4 source of interference such as a WiFi transmitter or microwave. This may be helpful to locate a Zigbee Endpoint device that is dropping off due to interference or weak signal. Closer to 0 the better as that means less power was used to transmit and is an indication of stronger signal strength. RSSI or Receiver Signal Strength ( B) - is a signed 8-bit integer ranging from approximately -100 to 127, with each value representing the energy level in dBm or decibel-milliwatts at the radio receiver.
An LQI below 200 represent links with high error rates, while and LQI of 200 represents approximately an 80% reliability of receiving the data packet intact. LQI data is also used by the Zigbee stack to determine connectivity between neighboring nodes, and to select parent devices when joining the network as a ZigBee end device.
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