Link cost#
For the purpose of packet filtering, LQI values are translated into ‘link cost’ values. Thus, a range of LQI values maps to a single link cost, which is an integer value. The default mappings implemented by the ZigBee PRO stack are shown in the table below.
‘LQI to Link Cost’ Mappings
LQI Range |
Link Cost |
|---|---|
≥ 51 |
1 |
46 - 50 |
2 |
41 - 45 |
3 |
39 - 40 |
4 |
36 - 38 |
5 |
25 - 35 |
6 |
≤ 24 |
7 |
The above mappings can be modified, as described in Section 6.10.3.3. A link cost of 5 is used as the packet filtering threshold by the NXP ZigBee PRO stack. Thus, packets with link costs greater than 5 may be discarded. For the device, this threshold is more suitable than the value of 3 proposed in the ZigBee specification. However, the threshold is configurable, as described in Section 6.10.3.3.
Parent topic:Filtering packets on LQI Value/Link cost