As the next hop in Zig Bee tree routing

parent and child nodes are stored in neighbor table.Due to the passive maintenance mechanism of neighbor relationship table

parent-child relationships are insensitive to the changeable wireless link which cause inaccurate maintenance of parent-child relationship and packet loss rate is increased.A link quality indicator（LQI）-based tree routing active maintenance（LQI-TRAM）mechanism for Zig Bee is proposed and Schmitt trigger idea is introduced to the circuit to enhance stablity.A node can detect the quality of links between itself and father-son nodes

and break the links which are not fit for routing to avoid packet loss rate.