A method for indicating a De Modulation Reference Signal, DMRS, applying to a Base Station, BS,, the method comprising: allocating (301, 601, 701, 901) DMRS configuration parameters comprising a designated DMRS port, a number of layers, and a length of Orthogonal Cover Codes, OCC, to User Equipment, UE,, according to a table of DMRS configuration parameters, wherein the table of DMRS configuration parameters comprises entries indicating DMRS configuration parameters of combinations of at least two lengths of OCCs; and sending (303, 601, 703, 901) a DMRS indication, wherein the DMRS indication is generated (302, 601, 702, 901) corresponding to information on the DMRS configuration parameters allocated to the UE, wherein the information on the DMRS configuration parameters comprises the length of the OCCs, wherein the table of DMRS configuration parameters comprises entries indicating DMRS configuration parameters for one-codeword transmission and entries indicating DMRS configuration parameters for two-codeword transmission, wherein the entries indicating DMRS configuration parameters for one-codeword transmission comprise four entries indicating DMRS configuration parameters for one-layer transmission with a length of the OCCs of 2, eight entries indicating DMRS configuration parameters for one-layer transmission with a length of the OCCs of 4, three entries indicating DMRS configuration parameters for two-layer to four-layer retransmission with the length of the OCCs of 4, and a reserved entry, wherein the entries indicating DMRS configuration parameters for two-codeword transmission comprise two entries indicating DMRS configuration parameters for two-layer transmission with the length of the OCCs of 2, four entries indicating DMRS configuration parameters for two-layer transmission with the length of the OCCs of 4, six entries indicating DMRS configuration parameters for Single-User, SU, three-layer to eight-layer transmission with the length of the OCCs of 4, and a reserved entry. allocating (301, 601, 701, 901) DMRS configuration parameters comprising a designated DMRS port, a number of layers, and a length of Orthogonal Cover Codes, OCC, to User Equipment, UE,, according to a table of DMRS configuration parameters, wherein the table of DMRS configuration parameters comprises entries indicating DMRS configuration parameters of combinations of at least two lengths of OCCs; and sending (303, 601, 703, 901) a DMRS indication, wherein the DMRS indication is generated (302, 601, 702, 901) corresponding to information on the DMRS configuration parameters allocated to the UE, wherein the information on the DMRS configuration parameters comprises the length of the OCCs, wherein the table of DMRS configuration parameters comprises entries indicating DMRS configuration parameters for one-codeword transmission and entries indicating DMRS configuration parameters for two-codeword transmission, wherein the entries indicating DMRS configuration parameters for one-codeword transmission comprise four entries indicating DMRS configuration parameters for one-layer transmission with a length of the OCCs of 2, eight entries indicating DMRS configuration parameters for one-layer transmission with a length of the OCCs of 4, three entries indicating DMRS configuration parameters for two-layer to four-layer retransmission with the length of the OCCs of 4, and a reserved entry, wherein the entries indicating DMRS configuration parameters for two-codeword transmission comprise two entries indicating DMRS configuration parameters for two-layer transmission with the length of the OCCs of 2, four entries indicating DMRS configuration parameters for two-layer transmission with the length of the OCCs of 4, six entries indicating DMRS configuration parameters for Single-User, SU, three-layer to eight-layer transmission with the length of the OCCs of 4, and a reserved entry.