rol DL: Downlink CPICH: Common Pilot Indicator Channel TTI: Transmission Time Interval RSCP: Received Signal Code Power RRC: Radio Resource Control UTRA: Universal Terrestrial Radio Access Figure 4.18 Measurements performed by the user equipment (UE). The UE mea- surements are instrumental for intra-LTE and inter-RAT mobility control and for channel-dependent (opportunistic) scheduling as well as other vital physical layer procedures such as power control and link adaptation. (See also reference 18.) © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology WCDMA. Positioning-related measurements are not listed because they depend upon the exact positioning method used in E-UTRAN [22]. Further details can be found in 3GPP TS 36.214 [20]. Reference symbol received power (RSRP) is determined for the consid- ered cell as the linear average over the power contributions (in [W]) of the resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth. Reference symbol received quality (RSRQ) is defined as the ratio NRSRP/ (E-UTRA carrier RSSI), where N is the number of RBs of the E-UTRA carrier RSSI measurement bandwidth. The measurements in the numerator and denominator should be made over the same set of resource blocks. E-UTRA carrier received signal strength indicator (RSSI) comprises the total received wideband power observed by the UE from all sources, includ- ing co-channel serving and nonserving cells, adjacent channel interference, thermal noise, etc. CQI is per sub-band, per group of sub-bands, and over the entire bandwidth. 4.3.2 Measurements Performed by the eNode B In E-UTRAN, certain types of measurements should be performed internally in the eNode B and will not be exchanged between the eNode Bs. These measure- ments do not need to be specified in the standard; rather, they will be implemen- tation dependent. On the other hand, measurements that are to be exchanged between the eNode Bs over the X2 interface need to 