A method in a receiver comprised in a first node in communication with a transmitter in a second node in a radio system, wherein multiple independent data streams are transmitted from subsets of a plurality of transmit antennas, said method comprising: determining for each transmit antenna, a co-phasing angle that maximizes the received signal power, said step of determining a co-phasing angle for each transmit antenna comprising: computing a prefilter weight matrix for each transmit antenna subset; computing a prefilter channel as a product of the prefilter weight matrix and a channel impulse response matrix; computing a trace metric of a prefilter channel autocorrelation matrix; maximizing the trace metric to decouple the input streams; and determining the co-phasing angles independently for each data stream; determining a partitioning of the plurality of transmit antennas that provides the highest channel capacity among all possible partitionings, wherein the step of determining a partitioning of the plurality of transmit antennas further comprises determining the number of transmit antenna subsets, which transmit antennas are included in each subset, and the capacity of the data stream to be transmitted from each transmit antenna subset, and wherein the step of determining a partitioning of the plurality of transmit antennas further comprises: hypothesizing every possible partition of the set of transmit antennas into subsets; for each antenna partitioning, determining the co-phasing angles to be applied to each transmit antenna in each subset; for each transmit antenna partitioning, determining a total channel capacity; and selecting the transmit antenna partitioning that provides the highest channel capacity; and providing to the transmitter, information regarding the determined co-phasing angle for each transmit antenna, and information regarding the transmit antenna partitioning such that the transmitter can partition the plurality of transmit antennas into mutually exclusive subsets in accordance with the determined partitioning information and apply a relative phase rotation to each transmit antenna in each subset in accordance with the co-phasing angles. determining for each transmit antenna, a co-phasing angle that maximizes the received signal power, said step of determining a co-phasing angle for each transmit antenna comprising: computing a prefilter weight matrix for each transmit antenna subset; computing a prefilter channel as a product of the prefilter weight matrix and a channel impulse response matrix; computing a trace metric of a prefilter channel autocorrelation matrix; maximizing the trace metric to decouple the input streams; and determining the co-phasing angles independently for each data stream; computing a prefilter weight matrix for each transmit antenna subset; computing a prefilter channel as a product of the prefilter weight matrix and a channel impulse response matrix; computing a trace metric of a prefilter channel autocorrelation matrix; maximizing the trace metric to decouple the input streams; and determining the co-phasing angles independently for each data stream; determining a partitioning of the plurality of transmit antennas that provides the highest channel capacity among all possible partitionings, wherein the step of determining a partitioning of the plurality of transmit antennas further comprises determining the number of transmit antenna subsets, which transmit antennas are included in each subset, and the capacity of the data stream to be transmitted from each transmit antenna subset, and wherein the step of determining a partitioning of the plurality of transmit antennas further comprises: hypothesizing every possible partition of the set of transmit antennas into subsets; for each antenna partitioning, determining the co-phasing angles to be applied to each transmit antenna in each subset; for each transmit antenna partitioning, determining a total channel capacity; and selecting the transmit antenna partitioning that provides the highest channel capacity; and providing to the transmitter, information regarding the determined co-phasing angle for each transmit antenna, and information regarding the transmit antenna partitioning such that the transmitter can partition the plurality of transmit antennas into mutually exclusive subsets in accordance with the determined partitioning information and apply a relative phase rotation to each transmit antenna in each subset in accordance with the co-phasing angles.