Section: 6.8A.5 Mapping to resource elements
Content: The block of complex-valued symbols shall be mapped in sequence starting with to resource elements on the associated antenna port which meet all of the following criteria: - they are part of the EREGs assigned for the EPDCCH transmission, and - they are assumed by the UE not to be used for cell-specific reference signals, where the positions of the cell-specific reference signals are given by clause 6.10.1.2 with the number of antenna ports for and the frequency shift of cell-specific reference signals derived as described in clause 6.10.1.2 unless other values for these parameters are provided by clause 9.1.4.3 in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [4], and - they are assumed by the UE not to be used for transmission of: - zero-power CSI reference signals, where the positions of the CSI reference signals are given by clause 6.10.5.2. The configuration for zero power CSI reference signals is - obtained as described in clause 6.10.5.2 unless other values are provided by clause 9.1.4.3 in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [4], and - obtained by higher-layer configuration of up to five reserved CSI-RS resources as part of the discovery signal configuration following the procedure for zero-power CSI-RS in clause 6.10.5.2. - non-zero-power CSI reference signals for CSI reporting, except for non-zero power CSI reference signals configured by csi-RS-ConfigNZP-ApList, with the configuration for non-zero power CSI reference signals for CSI reporting obtained as described in clause 6.10.5.2, and - for frame structure type 1 and 2, the index in the first slot in a subframe fulfils where is given by clause 9.1.4.1 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [4], and - for frame structure type 3, - if the higher layer parameter subframeStartPosition indicates 's07' and if the downlink transmission starts in the second slot of a subframe - the index in the second slot in the subframe fulfils where is given by clause 9.1.4.1 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [4], - otherwise - the index in the first slot in the subframe fulfils where is given by clause 9.1.4.1 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [4]. The mapping to resource elements on antenna port meeting the criteria above shall be in increasing order of first the index and then the index, starting with the first slot and ending with the second slot in a subframe. For localized transmission, the single antenna port to use is given by Table 6.8A.5-1 with where is the lowest ECCE index used by this EPDCCH transmission in the EPDCCH set, equals the C-RNTI, and is the number of ECCEs used for this EPDCCH. Table 6.8A.5-1: Antenna port to use for localized EPDCCH transmission For distributed transmission, each resource element in an EREG is associated with one out of two antenna ports in an alternating manner, starting with antenna port 107, where for normal cyclic prefix and for extended cyclic prefix.