Downlink Power Control In LTE

The eNodeB determines the downlink transmit energy per resource element (EPRE). Downlink cell-

specific reference-signal (RS) EPRE is constant across the downlink system bandwidth and constant

across all subframes until different cell-specific RS power information is received. The downlink RS EPRE

is given by the parameter Reference-signal-power provided by higher layers.

In cases 16QAM, 64QAM, spatial multiplex TRI>1 or multi-user MIMO the DL power is given by ρA and

ρB

A = + P power-offset ρ δ

or

10log (2) power-offset 10 = + + A A ρ δ P

(if precoding for transmit diversity with 4 cell-specific antenna ports is used.) Furthermore PA and PB are

signalled values, also setting the ratio

δpower-offset is used for multi-user

MIMO Depending on the number of antenna ports and CP configuration ρA and ρB are applied to the

OFDM symbols 0..6.