A transmission apparatus comprising: circuitry configured to, in operation: select a random seed out of a first random seed generated based on a cell ID when in multi-user multiple input multiple output, MU-MIMO, operation and, otherwise, a second random seed generated based on a second ID that is dedicatedly notified to a user equipment, UE, as a UE-specific ID or a group ID; initialize a scrambling sequence, which is used to scramble a demodulation reference signal, with the selected random seed; scramble the demodulation reference signal using the scramble sequence; and notify a receiver side of the selection of the first random seed and the second random seed by using signaling set with one codeword, wherein, eight values in the one codeword respectively indicate the following eight cases: one layer of signals configured with a first port and the first random seed with SCID=0; one layer of signals configured with the first port and the first random seed with SCID=1; one layer of signals configured with a second port and the first random seed with SCID=0; one layer of signals configured with the second port and the first random seed with SCID=1; two layers of signals configured with the first and the second ports and the second random seed; three layers of signals configured with the first, the second and a third ports and the second random seed; four layers of signals configured with the first to the third ports and a fourth port and the second random seed; and one layer of signals configured with the first port or the second port and the second random seed; and a transmitter configured to, in operation, transmit the demodulation reference signal; wherein the first random seed is generated by c _ init = ⌊ n _ s / 2 ⌋ + 1 ⋅ 2 cell _ id + 1 ⋅ 2 ∧ 16 + SCID wherein c_init is the first random seed, n_s is a slot number, cell_id is the cell ID, and SCID is 0 or 1. circuitry configured to, in operation: select a random seed out of a first random seed generated based on a cell ID when in multi-user multiple input multiple output, MU-MIMO, operation and, otherwise, a second random seed generated based on a second ID that is dedicatedly notified to a user equipment, UE, as a UE-specific ID or a group ID; initialize a scrambling sequence, which is used to scramble a demodulation reference signal, with the selected random seed; scramble the demodulation reference signal using the scramble sequence; and notify a receiver side of the selection of the first random seed and the second random seed by using signaling set with one codeword, wherein, eight values in the one codeword respectively indicate the following eight cases: one layer of signals configured with a first port and the first random seed with SCID=0; one layer of signals configured with the first port and the first random seed with SCID=1; one layer of signals configured with a second port and the first random seed with SCID=0; one layer of signals configured with the second port and the first random seed with SCID=1; two layers of signals configured with the first and the second ports and the second random seed; three layers of signals configured with the first, the second and a third ports and the second random seed; four layers of signals configured with the first to the third ports and a fourth port and the second random seed; and one layer of signals configured with the first port or the second port and the second random seed; and select a random seed out of a first random seed generated based on a cell ID when in multi-user multiple input multiple output, MU-MIMO, operation and, otherwise, a second random seed generated based on a second ID that is dedicatedly notified to a user equipment, UE, as a UE-specific ID or a group ID; initialize a scrambling sequence, which is used to scramble a demodulation reference signal, with the selected random seed; scramble the demodulation reference signal using the scramble sequence; and notify a receiver side of the selection of the first random seed and the second random seed by using signaling set with one codeword, wherein, eight values in the one codeword respectively indicate the following eight cases: one layer of signals configured with a first port and the first random seed with SCID=0; one layer of signals configured with the first port and the first random seed with SCID=1; one layer of signals configured with a second port and the first random seed with SCID=0; one layer of signals configured with the second port and the first random seed with SCID=1; two layers of signals configured with the first and the second ports and the second random seed; three layers of signals configured with the first, the second and a third ports and the second random seed; four layers of signals configured with the first to the third ports and a fourth port and the second random seed; and one layer of signals configured with the first port or the second port and the second random seed; and a transmitter configured to, in operation, transmit the demodulation reference signal; wherein the first random seed is generated by c _ init = ⌊ n _ s / 2 ⌋ + 1 ⋅ 2 cell _ id + 1 ⋅ 2 ∧ 16 + SCID wherein c_init is the first random seed, n_s is a slot number, cell_id is the cell ID, and SCID is 0 or 1.