What is RSRP? How is it Calculated ?
RSRP is Received Signal Reference Power which is the linear average power of the resource elements carrying the reference signal . Now when we talk about Reference signals there are DMRS(Demodulation Ref Signal) , SRS(Sounding Ref Signal) and cell specific reference signal(CRS). So in this specific case we are talking about the cell specific reference signal which is sent by the E-node-b and received by the UE to calculate the average.
RSRP calculation is based on energy received within useful part of OFDM symbol and doesn’t include cyclic prefix energy.
RSRP unit is dBm. UE reports not RSRP value but an integer value between 0 and 97.
Maximum RSRP value can be calculated based on maximum input UE power UE which is -25 dBm and minimal LTE bandwidth which is 1.4 MHz, i.e. 72 resource elements. Then -25 – 10*LOG(72) = -44 dBm. Absolute RSRP measurement accuracy is between ±6 and ±8 dB.