Method for precoding in an open loop transmission in a wireless multiple antenna radio communications system, wherein the system: - provides for rank adaptation for data transmission with selected transmission rank r being 1 ≤ r ≤ R, where R is maximum available transmission rank of the communication system, - communicates resource units containing resource elements, - provides N available Demodulation Reference Signals (DM-RS) for communication channel estimation in each RU. - provides a number of RE:s in each RU for data transmission - provides a number of E RE:s in each RU allocated for DM-RS transmission, the method comprising: - applying a number, N Used, of DM-RS:s, N Used ≤ N, to the E allocated RE:s, - precoding the data at each of the M RE:s within each RU with a precoding matrix (W1... W4), characterised by: - Precoding each of N Used DM-RSs over the E allocated REs within each RU with one column of a precoding matrix (W1... W4), - when precoding, using at least L ≥ 2 different precoding matrices (W1... W4) from a set of precoding matrices to precode the M RE:s and the E allocated RE:s in at least one RU for at least one certain rank r transmission such that RE:s precoded with a first precoding matrix are interleave with RE:s precoded with at least one additional, a second different precoding matrix, and wherein the number of used precoding matrices (W1... W4) L is adapted to the transmission rank r and number N of available DM-RS, wherein - when precoding, the DM-RS are also at the same time precoded with columns from the same at least L ≥ 2 different precoding matrices (W1... W4) from the set of precoding matrices. - provides for rank adaptation for data transmission with selected transmission rank r being 1 ≤ r ≤ R, where R is maximum available transmission rank of the communication system, - communicates resource units containing resource elements, - provides N available Demodulation Reference Signals (DM-RS) for communication channel estimation in each RU. - provides a number of RE:s in each RU for data transmission - provides a number of E RE:s in each RU allocated for DM-RS transmission, - applying a number, N Used, of DM-RS:s, N Used ≤ N, to the E allocated RE:s, - precoding the data at each of the M RE:s within each RU with a precoding matrix (W1... W4), characterised by: - Precoding each of N Used DM-RSs over the E allocated REs within each RU with one column of a precoding matrix (W1... W4), - when precoding, using at least L ≥ 2 different precoding matrices (W1... W4) from a set of precoding matrices to precode the M RE:s and the E allocated RE:s in at least one RU for at least one certain rank r transmission such that RE:s precoded with a first precoding matrix are interleave with RE:s precoded with at least one additional, a second different precoding matrix, and wherein the number of used precoding matrices (W1... W4) L is adapted to the transmission rank r and number N of available DM-RS, wherein - when precoding, the DM-RS are also at the same time precoded with columns from the same at least L ≥ 2 different precoding matrices (W1... W4) from the set of precoding matrices. - Precoding each of N Used DM-RSs over the E allocated REs within each RU with one column of a precoding matrix (W1... W4), - when precoding, using at least L ≥ 2 different precoding matrices (W1... W4) from a set of precoding matrices to precode the M RE:s and the E allocated RE:s in at least one RU for at least one certain rank r transmission such that RE:s precoded with a first precoding matrix are interleave with RE:s precoded with at least one additional, a second different precoding matrix, and wherein the number of used precoding matrices (W1... W4) L is adapted to the transmission rank r and number N of available DM-RS, wherein - when precoding, the DM-RS are also at the same time precoded with columns from the same at least L ≥ 2 different precoding matrices (W1... W4) from the set of precoding matrices.