, where for FDD kSRS ={ 0 , 1 , , , , 0 } is the subframe index within the frame , for TDD serving cell kSRS is defined in Table 8 . 2 - 3 . The SRS transmission instances for TDD serving cell with TSRS = 2 are the subframes satisfying kSRS - Toffset . For TDD serving cell , and a UE configured for type 0 triggered SRS transmission in serving cell c , and the UE configured with the parameter EIMTA - MainConfigServCell - r 12 for serving cell c , if the UE does not detect an UL / DL configuration indication for radio frame m ( as described in section 13 . 1 ) , the UE shall not transmit trigger type 0 SRS in a subframe of radio frame m that is indicated by the parameter eimta - HarqReferenceConfig - r 12 as a downlink subframe unless the UE transmits PUSCH in the same subframe . Trigger type 1 SRS configuration of a UE in a serving cell for SRS periodicity , TSRS , 1 , and SRS subframe offset , Toffset , 1 , is defined in Table 8 . 2 - 4 and Table 8 . 2 - 5 , for FDD and TDD serving cell , respectively . The periodicity TSRS , 1 of the SRS transmission is serving cell specific and is selected from the set { 2 , 5 , 10 } ms or subframes . For the SRS periodicity TSRS , 1 of 2 ms in TDD serving cell , two SRS resources are configured in a half frame containing UL subframe ( s ) of the given serving cell . A UE configured for type 1 triggered SRS transmission in serving cell c and not configured with a carrier indicator field shall transmit SRS on serving cell c upon detection of a positive SRS request in PDCCH / EPDCCH scheduling PUSCH / PDSCH on serving cell c . A UE configured for type 1 triggered SRS transmission in serving cell c and configured with a carrier indicator field shall transmit SRS on serving cell c upon detection of a positive SRS request in PDCCH / EPDCCH scheduling PUSCH / PDSCH with the value of carrier indicator field corresponding to serving cell c . A UE configured for type 1 triggered SRS transmission on serving cell c upon detection of a positive SRS request in subframe n of serving cell c shall commence SRS transmission in the first subframe satisfying