Section: 6.2.8 Guard period for narrowband and wideband retuning
Content: For BL/CE UEs, a guard period of at most OFDM symbols is created for Rx-to-Rx and Tx-to-Rx frequency retuning between two consecutive subframes. - If the higher layer parameter ce-RetuningSymbols is set, then equals ce-RetuningSymbols, otherwise . - If the higher layer parameter ce-pdsch-maxBandwidth-config is set to 5 MHz, then the rules for guard period creation defined in the remainder of this clause apply not for retuning between narrowbands but for retuning between widebands and for transmissions involving multiple widebands. - If the UE is configured with CEModeA and higher layer parameter ce-PDSCH-FlexibleStartPRB-AllocConfig, the rules for guard period creation defined in the remainder of this clause apply for retuning between tuning narrowbands defined for the allocation resources not fully within one narrowband defined in Clause 6.2.7 as the consecutive 6PRBs starting from if is aligned with RBG boundary, or the consecutive 6PRBs ending at if is aligned with RBG boundary, where and are defined in Table 7.1.6.3-2 [4]. - If the UE is configured with CEModeB and higher layer parameter ce-PDSCH-FlexibleStartPRB-AllocConfig, the rules for guard period creation defined in the remainder of this clause apply for retuning between the tuning narrowband defined as the narrowband shifted according to Table 6.2.7-1. - If the UE retunes from a first downlink narrowband to a second downlink narrowband with a different center frequency, a guard period is created by the UE not receiving at most OFDM symbols in the second narrowband. - If the UE retunes from a first uplink narrowband to a second downlink narrowband with a different center frequency for frame structure type 2, a guard period is created by the UE not receiving at most OFDM symbols in the second narrowband. Furthermore, for BL/CE UEs configured with the higher layer parameter srs-UpPtsAdd, a guard period of at most OFDM or SC-FDMA symbols is created for Rx-to-Tx frequency retuning within a special subframe for frame structure type 2. Primarily, the TDD guard period (GP) specified in clause 4.2 serves as the guard period for narrowband retuning, and if GP is not sufficient then additional guard period is created by the UE according to: - If SRS is configured to be transmitted in the first UpPTS symbol, the additional guard period is created by the UE not receiving at most DwPTS symbols in the first narrowband. - If SRS is configured to be transmitted in the second UpPTS symbol but not in the first UpPTS symbol, the additional guard period is created by the UE primarily by not transmitting the first UpPTS symbol and (if ) secondarily by not receiving the last DwPTS symbol.