Power gain and sensitivity

When configuring a node and a network, one important parameter is related with power gain and sensitivity.

Power level

Power level (dBm) at which the RF module transmits conducted power. Its possible values are:

Parameter

XBee 3 802.15.4

XBee 3 802.15.4 EU

0

10 dBm

-5 dBm

1

12 dBm

-1 dBm

2

14 dBm

2 dBm

3

16 dBm

5 dBm

4

18 dBm

8 dBm

Figure: Transmission power values

dBm is a standard unit to measure power level taking as reference a 1mW signal. Values expressed in dBm can be easily converted to mW using the next formula: mW = 10^(value dBm/10)

Graphic about transmission power is exposed next:

Figure : XBee 3 output power level

Example of use:

{
xbee802.setPowerLevel(0);
xbee802.getPowerLevel();
}

Related variables:

xbee802.powerLevel // stores the power output level selected

Power level configuration example: https://development.libelium.com/802-15-setread-power-level/

Received Signal Strength Indicator

It reports the Received Signal Strength of the last received RF data packet. It only indicates the signal strength of the last hop, so it does not provide an accurate quality measurement of a multihop link.

Example of use:

{
xbee802.getRSSI();
}

Related variables:

xbee802.valueRSSI // stores the RSSI of the last received packet

The returned command value is measured in -dBm. For example if xbee802.valueRSSI=0x60, then the RSSI of the last packet received was -96 dBm. The ideal working mode is getting the maximum coverage with the minimum power level. Thereby, a compromise between power level and coverage appears. Each application scenario will need some tests to find the best combination of both parameters.

Getting RSSI example: https://development.libelium.com/802-08-get-rssi/