To check the connectivity between say, Node A and Node B,
1. GET_RX_POWER_dbm(tx, rx, time) is the API using which you can easily calculate the received power by passing the transmitter id(tx), receiver id(rx) and the current simulation time(time).
GET_RX_POWER_dbm(Device id of A, Device id of B, Current Simulation time) - will give you the received power at B.
2. dRxSensitivity is part of the PhyParameters of each device which can be used to compare with the calculated Rx power calculated in the previous step.
if(RXpower>dRxSensitivity) then it can be assumed that B is connected to A.
If mobility is configured in the nodes, the above calculations can be done each time the nodes move.