If the subcarrier spacing (SCS) of a low-frequency cell Is 30 kHz and the bandwidth...

The theoretically noise (dBm) over the air interface should be -116 dBm. The noise is calculated by subtracting the noise figure of the receiver from the thermal noise floor, which is determined by the subcarrier spacing and the bandwidth of each Resource Block (RB). In this case, the subcarrier spacing is 30 kHz and the bandwidth of each RB is 360 kHz, so the thermal noise floor is -116 dBm.