Calculate 4G LTE Cell Reference Signal (CRS) power per RE from eNodeB transmit power and system bandwidth.
RS RE Power (dBm)
N_PRB
Total subcarriers
RS RE Power (dBm)
PDSCH RE Power (dBm)
RS power per port (dBm)
Theoretical max RSRP at 0 m (dBm)
RS RE Power is the power radiated on each Reference Signal subcarrier. RSRP is measured by UE as the linear average of RS RE powers. The ρA offset adjusts PDSCH power relative to CRS power.
Frequently Asked Questions
What is LTE RS Power (CRS power)?
LTE RS Power (also called CRS power or reference signal power) is the power transmitted on each Cell-specific Reference Signal resource element. It equals the total eNodeB transmit power divided by the number of active subcarriers in the bandwidth. A typical RS power for a 20 MHz macro cell with 46 dBm TX power is approximately 15–17 dBm. This value is broadcast in the SIB and used by UEs to calibrate RSRP measurements.
What is the difference between RS power and RSRP?
RS Power is the transmitted power per RE at the eNodeB antenna port. RSRP (Reference Signal Received Power) is what the UE measures after the signal has propagated through the radio channel, experiencing path loss, shadowing, and multipath. RSRP = RS_Power − Path_Loss. Practically, RSRP ranges from about −44 dBm (very close to the base station) to −140 dBm at the cell edge. The RS Power value is used as a reference in neighbor cell RSRP offset calculations.
How does ρA affect PDSCH performance?
ρA is the power offset of PDSCH REs relative to the CRS RE power, signaled via higher-layer parameter pdsch-ConfigDedicated. A positive ρA boosts PDSCH above CRS power, improving PDSCH SINR in coverage-limited scenarios. A negative ρA reduces PDSCH power when UEs are close to the cell, conserving power budget. In practice ρA is typically 0 dB for most deployments, adjusted based on network optimization targets.