These values: 46dBm for bands 10, 15, 20MHz and 43dBm for 1.4, 3, 5MHz are given in the specification 3GPP TS 36.942, which provides models (of environment, UE and eNB) to be used in system level simulations. However, the standard does not specify the transmit power of eNB, beyond that it shall be defined by the local regulator and manufacturer.