Section: 10.2.6 Narrowband reference signal (NRS)
Content: Before a UE obtains operationModeInfo: - If frame structure type 1 is used, the UE may assume narrowband reference signals (NRSs) are transmitted in subframes #0 and #4 and in subframes #9 not containing NSSS. - If frame structure type 2 is used, the UE may assume narrowband reference signals (NRSs) are transmitted in subframes #9 and in subframes #0 not containing NSSS. On an NB-IoT carrier for which a UE receives higher-layer parameter operationModeInfo indicating guardband or standalone. - If frame structure type 1 is used, before the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0, #1, #3, #4 and in subframes #9 not containing NSSS. - If frame structure type 2 is used, before the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #9, and in subframes #0 not containing NSSS, and in subframes #4 if subframes #4 is configured for SystemInformationBlockType1-NB transmissions. - If frame structure type 1 is used, after the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0, #1, #3, #4, subframes #9 not containing NSSS, and in NB-IoT downlink subframes. - If frame structure type 2 is used, after the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #9, subframes #0 not containing NSSS, in subframes #4 if subframes #4 is configured for SystemInformationBlockType1-NB transmissions, and in NB-IoT downlink subframes. On an NB-IoT carrier for SystemInformationBlockType1-NB for which sib1-carrierInfo-NB indicates non-anchor for frame structure type 2, before the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0 and #5. After the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0, #5, and in NB-IoT downlink subframes indicated by tdd-SI-SubframesBitmap. On an NB-IoT carrier for which DL-CarrierConfigCommon-NB is present and no inbandCarrierInfo is present. - If frame structure type 1 is used and when an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the P-RNTI and higher-layer indicates nrs-NonAnchorConfig is enabled, the UE first determines the starting subframe of NPDCCH search space associated with NRS transmission according to [10]. - If higher-layer nB is configured as fourT, the UE may assume NRSs are transmitted in the 10th NB-IoT DL subframe before the determined starting subframe of NPDCCH search space. - If higher-layer nB is configured as twoT, the UE may assume NRSs are transmitted in the 9th and 10th NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - If higher-layer nB is configured as oneT, the UE may assume NRSs are transmitted in the 6th, 7th, 8th, 9th and 10th NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - For other nB values, the UE may assume NRSs are transmitted in 10 NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - When an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the P-RNTI, the UE may assume NRSs are transmitted in the NPDCCH candidate where the UE finds a DCI with CRC scrambled by the P-RNTI. The UE may also assume NRSs are transmitted in 10 NB-IoT DL subframes before and in 4 NB-IoT DL subframes after the NPDCCH candidate where the UE finds a DCI with CRC scrambled by the P-RNTI, where NB-IoT DL subframes without NRS are not counted. If the DCI with CRC scrambled by the P-RNTI schedules a NPDSCH, the UE may assume NRSs are transmitted in the NB-IoT DL subframes carrying the NPDSCH as well as in 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - During the window controlled by higher layers where the UE shall attempt to decode the NPDCCH with DCI scrambled by RA-RNTI (see [8], clause 5.1.4), the UE may assume NRSs are transmitted in the Type-2 CSS configured by higher layers, as well as in 10 NB-IoT DL subframes before and in 4 NB-IoT DL subframes after each Type-2 CSS, where NB-IoT DL subframes without NRS are not counted. If a DCI scrambled by the RA-RNTI is detected, the UE may assume NRSs are transmitted in the NPDSCH scheduled by the DCI scrambled by the RA-RNTI, as well as in 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. In addition, when the UE attempts to decode a DCI with CRC scrambled by the RA-RNTI as well as receiving the NPDSCH scheduled by the DCI scrambled by the RA-RNTI, the UE may assume NRSs are transmitted in subframes #0, #1, #3, #4 and #9. - During random access procedure, when an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the temporary C-RNTI and/or the C-RNTI, before the DCI scrambled by temporary C-RNTI and/or C-RNTI is detected, the UE may assume NRSs are transmitted in the Type-2 CSS configured by higher layers, as well as in 10 NB-IoT DL subframes before the start of each Type-2 CSS and in 4 NB-IoT DL subframes after the end of each Type-2 CSS until the mac-ContentionResolutionTimer expires, where NB-IoT DL subframes without NRS are not counted. If a DCI scrambled by the temporary C-RNTI or C-RNTI is detected, the UE may assume NRSs are transmitted in the NPDSCH scheduled by the DCI scrambled by the temporary C-RNTI or C-RNTI as well as in 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - An NB-IoT UE may assume NRSs are transmitted in NB-IoT DL subframes that are used for Type1A-NPDCCH common search space, and Type2A-NPDCCH common search space, as well as in 10 NB-IoT DL subframes prior and in 4 NB-IoT DL subframes after each Type1A-NPDCCH common search space and Type2A-NPDCCH common search space. A UE may assume NRSs are transmitted in NB-IoT DL subframes carrying NPDSCH scheduled by DCI CRC scrambled by G-RNTI or SC-RNTI as well as 4 NB-IoT DL subframes prior and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - In other cases, if frame structure typ1 is used, the UE may assume NRSs are transmitted in subframes #0, #1, #3, #4, #9, and in NB-IoT downlink subframes and shall not expect NRSs in other downlink subframes. On an NB-IoT carrier for which a UE receives higher-layer parameter operationModeInfo indicating inband-SamePCI or inband-DifferentPCI. - If frame structure type 1 is used, before the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0, #4 and in subframes #9 not containing NSSS, and in subframes #3 which contain SystemInformationBlockType1-NB when additionalTransmissionSIB1 is configured as TRUE. - If frame structure type 2 is used, before the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #9, and in subframes #0 not containing NSSS, and in subframes #4 if subframes #4 is configured for SystemInformationBlockType1-NB transmissions. - If frame structure type 1 is used, after the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #0, #4, subframes #9 not containing NSSS, subframes #3 which contain SystemInformationBlockType1-NB when additionalTransmissionSIB1 is configured as TRUE, and in NB-IoT downlink subframes. - If frame structure type 2 is used, after the UE obtains SystemInformationBlockType1-NB, the UE may assume narrowband reference signals are transmitted in subframes #9, subframes #0 not containing NSSS, in subframes #4 if subframes #4 is configured for SystemInformationBlockType1-NB transmissions, and in NB-IoT downlink subframes On an NB-IoT carrier for which DL-CarrierConfigCommon-NB is present and inbandCarrierInfo is present: - If frame structure type 1 is used, when an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the P-RNTI and higher-layer indicates nrs-NonAnchorConfig is enabled, the UE first determines the starting subframe of NPDCCH search space associated with NRS transmission according to [10]. - If higher-layer nB is configured as fourT, the UE may assume NRSs are transmitted in the 10th NB-IoT DL subframe before the determined starting subframe of NPDCCH search space. - If higher-layer nB is configured as twoT, the UE may assume NRSs are transmitted in 9th and 10th NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - If higher-layer nB is configured as oneT, the UE may assume NRSs are transmitted in 6th, 7th, 8th, 9th and 10th NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - For other nB values, the UE may assume NRSs are transmitted in 10 NB-IoT DL subframes before the determined starting subframe of NPDCCH search space. - When an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the P-RNTI, the UE may assume NRSs are transmitted in the NPDCCH candidate where the UE finds a DCI with CRC scrambled by the P-RNTI. The UE may also assume NRSs are transmitted in10 NB-IoT DL subframes before and in 4 NB-IoT DL subframes after the NPDCCH candidate, where NB-IoT DL subframes without NRS are not counted. If the DCI with CRC scrambled by the P-RNTI schedules a NPDSCH, the UE may assume NRSs are transmitted in the NB-IoT DL subframes carrying the NPDSCH as well as 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - During the window controlled by higher layers where the UE shall attempt to decode the NPDCCH with DCI scrambled by RA-RNTI (see [8], clause 5.1.4), the UE may assume NRSs are transmitted in the Type-2 CSS configured by higher layers, as well as in 10 NB-IoT DL subframes before and in 4 NB-IoT DL subframes after each Type-2 CSS, where NB-IoT DL subframes without NRS are not counted. If a DCI scrambled by the RA-RNTI is detected, the UE may assume NRSs are transmitted in the NPDSCH scheduled by the DCI scrambled by the RA-RNTI, as well as in 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. In addition, when the UE attempts to decode a DCI with CRC scrambled by the RA-RNTI as well as receiving the NPDSCH scheduled by the DCI scrambled by the RA-RNTI, the UE may assume NRSs are transmitted in subframes #0, #4 and #9. - During random access procedure, when an NB-IoT UE is configured by higher layers to decode NPDCCH with CRC scrambled by the temporary C-RNTI and/or the C-RNTI, before the DCI scrambled by temporary C-RNTI and/or C-RNTI, is detected, the UE may assume NRSs are transmitted in the Type-2 CSS configured by higher layers, as well as in 10 NB-IoT DL subframes before the start of each Type-2 CSS and in 4 NB-IoT DL subframes after the end of each Type-2 CSS until the mac-ContentionResolutionTimer expires, where NB-IoT DL subframes without NRS are not counted. If a DCI scrambled by the temporary C-RNTI or C-RNTI is detected, the UE may assume NRSs are transmitted in the NPDSCH scheduled by the DCI scrambled by the temporary C-RNTI or C-RNTI as well as in 4 NB-IoT DL subframes before and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - An NB-IoT UE may assume NRSs are transmitted in NB-IoT DL subframes that are used for Type1A-NPDCCH common search space, and Type2A-NPDCCH common search space, as well as in 10 NB-IoT DL subframes prior and in 4 NB-IoT DL subframes after each Type1A-NPDCCH common search space and Type2A-NPDCCH common search space, where NB-IoT DL subframes without NRS are not counted. A UE may assume NRSs are transmitted in NB-IoT DL subframes carrying NPDSCH scheduled by DCI CRC scrambled by G-RNTI or SC-RNTI as well as in 4 NB-IoT DL subframes prior and after the scheduled NPDSCH, where NB-IoT DL subframes without NRS are not counted. - In other cases, if frame structure type 1 is used, the UE may assume NRSs are transmitted in subframes #0, #4, #9, and in NB-IoT downlink subframes and shall not expect NRSs in other downlink subframes. On an NB-IoT carrier for which DL-CarrierConfigDedicated-NB is present and no inbandCarrierInfo is present: - If frame structure type 1 is used, the UE may assume NRSs are transmitted in subframes #0, #1, #3, #4, #9, and in NB-IoT downlink subframes and shall not expect NRSs in other downlink subframes. On an NB-IoT carrier for which DL-CarrierConfigDedicated-NB is present and inbandCarrierInfo is present: - If frame structure type 1 is used, the UE may assume NRSs are transmitted in subframes #0, #4, #9, and in NB-IoT downlink subframes and shall not expect NRSs in other downlink subframes. An NB-IoT UE may assume NRSs are not transmitted in subframes that are configured by higher layer parameter nprsBitmap for narrowband positioning reference signal transmission.