Section: 7.7 HARQ RTT Timers
Content: The parameters RTToffset and DLoffset provides offsets for determining the HARQ round trip time. The parameter RTToffset is set to 0 in terrestrial networks and RTToffset is set to UE-eNB RTT in Non-terrestrial networks. The parameter DLoffset is set to 0 in terrestrial networks and DLoffset is set to Koffset + k-Mac in Non-terrestrial networks where Koffset is defined in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]. For each serving cell, in case of FDD configuration not configured with subframeAssignment-r15 and in case of Frame Structure Type 3 configuration on the serving cell which carries the HARQ feedback for this serving cell the HARQ RTT Timer is set to 8 subframes. For each serving cell, in case of TDD configuration or FDD with subframeAssignment-r15 configured on the serving cell which carries the HARQ feedback for this serving cell the HARQ RTT Timer is set to k + 4 subframes, where k is the interval between the downlink transmission and the transmission of associated HARQ feedback, as indicated in clauses 10.1 and 10.2 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2], and for an RN configured with rn-SubframeConfig, as specified in TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8] and not suspended, as indicated in Table 7.5.1-1 of TS 36.216[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer for relaying operation ]  [11]. For each serving cell, for HARQ processes scheduled using Short Processing Time (TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8]) the HARQ RTT Timer is set to 6 subframes for FDD and Frame Structure Type 3 and set to k + 3 subframes for TDD, where k is the interval between the downlink transmission and the transmission of associated HARQ feedback, as indicated in clauses 10.1 and 10.2 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]. For each serving cell, for HARQ processes scheduled using short TTI (TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8]) the HARQ RTT Timer is set to 8 TTIs if the TTI length is one slot or if proc-Timeline is set to n+4 set1, to 12 TTIs if proc-Timeline is set to n+6 set1 or n+6 set2 and to 16 TTIs if proc-Timeline is set to n+8 set2 for FDD and Frame Structure Type 3. For TDD short TTI the HARQ RTT Timer is set to k + 4 TTIs, where k is the interval between the downlink transmission and the transmission of associated HARQ feedback, as indicated in clauses 10.1 and 10.2 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]. For BL UEs and UEs in enhanced coverage, when single TB is scheduled by PDCCH the HARQ RTT Timer corresponds to 7 + N subframes plus DLoffset, where N is the used PUCCH repetition factor, where only valid (configured) UL subframes as configured by upper layers in fdd-UplinkSubframeBitmapBR are counted for N. In case of TDD, HARQ RTT Timer corresponds to 3 + k + N subframes, where k is the interval between the last repetition of downlink transmission and the first repetition of the transmission of associated HARQ feedback, and N is the used PUCCH repetition factor, where only valid UL subframes are counted for N as indicated in clauses 10.1 and 10.2 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]. For BL UEs and UEs in enhanced coverage, when multiple TBs are scheduled by PDCCH and HARQ-ACK bundling is not configured, the HARQ RTT Timer corresponds to 7 + m * N subframes plus DLoffset, where N is the used PUCCH repetition factor and m is the number of scheduled TBs as indicated in PDCCH whose associated HARQ process is with enabled HARQ feedback, where only valid (configured) UL subframes as configured by upper layers in fdd-UplinkSubframeBitmapBR are counted for m * N. For BL UEs and UEs in enhanced coverage, when multiple TBs are scheduled by PDCCH and HARQ-ACK bundling is configured the HARQ RTT Timer corresponds to 7 + M * N subframes plus DLoffset, where N is the used PUCCH repetition factor and M is the number of TB bundles as specified in clause 7.3 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2], where only valid (configured) UL subframes as configured by upper layers in fdd-UplinkSubframeBitmapBR are counted for M * N. For NB-IoT, when single TB is scheduled by PDCCH or when multiple TBs are scheduled for the interleaved case when HARQ-ACK bundling is configured the HARQ RTT Timer is set to k+3+N subframes plus RTToffset + deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 3 subframes plus RTToffset to the first subframe of the next PDCCH occasion. For NB-IoT, when multiple TBs are scheduled by PDCCH for the non-interleaved case or for the interleaved case when HARQ-ACK bundling is not configured, the HARQ RTT Timer is set to k+m*N+1 subframes plus RTToffset + deltaPDCCH where k is the interval between the last subframe of the downlink transmission and the first subframe of the first HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback and m is the number of scheduled TBs as indicated in PDCCH whose associated HARQ process is with enabled HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the last HARQ feedback transmission plus 1 subframe plus RTToffset to the first subframe of the next PDCCH occasion. Except for NB-IoT and for HARQ processes scheduled using Short Processing Time and for short TTI, UL HARQ RTT Timer length is set to 4 subframes plus RTToffset for FDD and Frame Structure Type 3, and set to kULHARQRTT subframes for TDD, where kULHARQRTT equals to the kPHICH value indicated in Table 9.1.2-1 of TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2] if the UE is not configured with upper layer parameter symPUSCH-UpPts for the serving cell, otherwise the kPHICH value is indicated in Table 9.1.2-3. For NB-IoT, when single TB is scheduled by PDCCH the UL HARQ RTT timer length is set to 4 subframes plus RTToffset + deltaPDCCH, where deltaPDCCH is the interval starting from the subframe following the last subframe of the PUSCH transmission plus 3 subframes plus RTToffset to the first subframe of the next PDCCH occasion. For NB-IoT, when multiple TBs are scheduled by PDCCH the UL HARQ RTT timer length is set to 2 subframes plus RTToffset + deltaPDCCH, where deltaPDCCH is the interval starting from the subframe following the last subframe of the PUSCH transmission plus 1 subframe plus RTToffset to the first subframe of the next PDCCH occasion. For HARQ processes scheduled using Short Processing Time (TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8]), the UL HARQ RTT Timer length is set to 3 subframes for FDD and for Frame Structure Type 3, and set to kULHARQRTT subframes for TDD, where kULHARQRTT equals the value indicated in Table 7.7-1 and Table 7.7-2. For HARQ processes scheduled using short TTI (TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8]), the UL HARQ RTT Timer length is set to 8 TTIs if the TTI length is one slot or if proc-Timeline is set to n+4 set1, to 12 TTIs if proc-Timeline is set to n+6 set1 or n+6 set2 and to 16 TTIs if proc-Timeline is set to n+8 set2 for FDD and Frame Structure Type 3. For TDD short TTI the UL HARQ RTT Timer is set to kULHARQRTT TTIs, where kULHARQRTT equals the value indicated in Table 7.7-3, Table 7.7-4 and Table 7.7-5. Table 7.7-1: kULHARQRTT for TDD Short Processing Time when special subframe configurations 0~9 is configured Table 7.7-2: kULHARQRTT for TDD Short Processing Time applied when special subframe configuration 10 is configured Table 7.7-3: kULHARQRTT for TDD short TTI applied when special subframe configurations 1, 2, 3, 4, 6, 7 and 8 are configured Table 7.7-4: kULHARQRTT for TDD short TTI applied when special subframe configurations 0, 5 and 9 are configured Table 7.7-5: kULHARQRTT for TDD short TTI applied when special subframe configuration 10 is configured NOTE 1: Void NOTE 2: Void