In the case of the legacy LTE system, allocation of the DL signal transmit power in the existing DL SF may be determined by the following parameters.

• • P_R: CRS RE transmit power (linear average in [W])
  • P_A: A ratio of PDSCH RE transmit power in a transmission symbol in which the CRS is not transmitted to CRS RE transmit power (in [dB])
  • P_B: A ratio of PDSCH RE transmit power in a transmission symbol in which CRS is transmitted to CRS RE transmit power (in [dB])
  • P_C: A ratio of PDSCH RE transmit power (in a transmission symbol in which CRS is not transmitted) to CSI-RS RE transmit power (in [dB])

Specifically, the eNB determines the DL transmit power for each RE. The UE assumes that the CRS RS EPRE (Energy Per Resource Element) (i.e., P_R) is constant over the entire DL BW and is constant over all subframes until new CRS power information is received. The CRS RS EPRE may be inferred based on a parameter (e.g., referenceSignalPower) provided by higher layer (e.g., RRC) signaling. The ratio of the PDSCH EPRE to the CRS RS EPRE (i.e., PDSCH EPRE/CRS RS EPRE) is set differently considering the CRS distribution. For example, one of P_A and P_B may be inferred and determined based on a parameter provided by higher layer (e.g., RRC) signaling, and the other one of P_A and P_B may be determined using the ratios therebetween. For example, P_A/P_B may have various values such as 1, 4/5, 3/5, and 2/5 depending on CRS distribution (e.g., the number of antenna ports).