Network node for a wireless communication system , the network node comprising: a transceiver configured to transmit a first control signal (S1) to a user device , the first control signal (S1) comprising a measurement request for at least one first reference signal (RS1), transmit the first reference signal (RS1) to the user device , receive a second control signal (S2) from the user device , the second control signal (S2) comprising a measurement report indicating a measurement of the first reference signal (RS1) at the user device , receive a second reference signal (RS2) from the user device ; a processor configured to measure a received power of the second reference signal (RS2), calculate at least one gain (G) between the network node and the user device based on the measurement of the first reference signal (RS1) and the received power of the second reference signal (RS2), when the user device enters an idle state or a detached state, store the calculated gain (G) or the received power of the second reference signal (RS2) in a memory ; or when the user device returns from the idle state or the detached state, retrieve the calculated gain (G) or the received power of the second reference signal (RS2) from the memory . a transceiver configured to transmit a first control signal (S1) to a user device , the first control signal (S1) comprising a measurement request for at least one first reference signal (RS1), transmit the first reference signal (RS1) to the user device , receive a second control signal (S2) from the user device , the second control signal (S2) comprising a measurement report indicating a measurement of the first reference signal (RS1) at the user device , receive a second reference signal (RS2) from the user device ; transmit a first control signal (S1) to a user device , the first control signal (S1) comprising a measurement request for at least one first reference signal (RS1), transmit the first reference signal (RS1) to the user device , receive a second control signal (S2) from the user device , the second control signal (S2) comprising a measurement report indicating a measurement of the first reference signal (RS1) at the user device , receive a second reference signal (RS2) from the user device ; a processor configured to measure a received power of the second reference signal (RS2), calculate at least one gain (G) between the network node and the user device based on the measurement of the first reference signal (RS1) and the received power of the second reference signal (RS2), when the user device enters an idle state or a detached state, store the calculated gain (G) or the received power of the second reference signal (RS2) in a memory ; or when the user device returns from the idle state or the detached state, retrieve the calculated gain (G) or the received power of the second reference signal (RS2) from the memory . measure a received power of the second reference signal (RS2), calculate at least one gain (G) between the network node and the user device based on the measurement of the first reference signal (RS1) and the received power of the second reference signal (RS2), when the user device enters an idle state or a detached state, store the calculated gain (G) or the received power of the second reference signal (RS2) in a memory ; or when the user device returns from the idle state or the detached state, retrieve the calculated gain (G) or the received power of the second reference signal (RS2) from the memory . <EOS>