Section: 10.2.6B.2 Mapping to resource elements
Content: The same antenna port shall be used for all symbols of the NWUS within a subframe. The UE shall not assume that the NWUS is transmitted on the same antenna port as any of the downlink reference signals or synchronization signals. If only one NRS port is configured by the eNB, the UE may assume the transmission of all NWUS subframes is using the same antenna port; otherwise, the UE may assume the same antenna port is used for NWUS transmission in DL subframes w0+2n and w0+2n+1, where w0 is the first DL subframe of the NWUS transmission as specified in [4], and n=0,1,…. The NWUS sequence is mapped to the set of subframes in the actual NWUS duration as defined in [4], where in a subframe #4 in which SystemInformationBlockType1-NB is transmitted or a subframe in which an SI message is transmitted, the subframe is counted in the NWUS mapping but not used for transmission of NWUS.On an NB-IoT carrier for which a UE receives higher-layer parameter operationModeInfo indicating inband-SamePCI, inband-DifferentPCI, guardband or standalone or on an NB-IoT carrier for which DL-CarrierConfigCommon-NB is present, the NWUS sequence shall be mapped to resource elements in sequence, starting with in increasing order of first the index over the 12 assigned subcarriers and then the index in each subframe in which NWUS is transmitted. Additionally, on an NB-IoT carrier for which a UE receives higher-layer parameter operationModeInfo indicating guardband or standalone, or on an NB-IoT carrier for which DL-CarrierConfigCommon-NB is present and no inbandCarrierInfo is present, the resource mapping for the first three OFDM symbols in the subframe is performed as follows: - The resource element (k,7) is mapped to resource element (k,0) of every index k over 12 assigned subcarriers - The resource element (k,8) is mapped to resource element (k,1) of every index k over 12 assigned subcarriers - The resource element (k,9) is mapped to resource element (k,2) of every index k over 12 assigned subcarriers A resource element overlapping with resource elements where cell-specific reference signals according to clause 6.10 are transmitted or NRSs according to clause 10.2.6 are transmitted shall not be used for NWUS transmission but is counted in the mapping process.