RSRP is used to measure the coverage of the LTE cell on the DL

RSRP is used to measure the coverage of the LTE cell on the DL. The UE will send RRC measurement
reports that include RSRP values in a binned format. The reporting range of RSRP is defined from−140 to−44 dBm with 1 dB resolution.
The main purpose of RSRP is to determine the best cell on the DL radio interface and select this
cell as the serving cell for either initial randomaccess or intra-LTE handover. The RRC measurement
reports with RSRP measurement results will be sentby the UE if a predefined event trigger criterion
is met
RSRP measurement results can be categorized in three ranges.
If RSRP>−75 dBm, excellent QoS can be expected as long as not too many subscribers struggle for
the available bandwidth of the cell. In the range between −75 and−95 dBm a slight degradation of
the QoS can be expected, for example, throughput will decline by 30–50% if RSRP goes down from
−75 to−95 dBm. Below−95 dBm the QoS become unacceptable and throughput tends to decline
down to zero at approximately−108 to−100 dBm. Under such radio conditions, call drops must be
expected as the worst case.