A method for measuring and reporting transmission characteristics of a propagation channel in a multiple input/multiple output, MIMO, communication system, comprising the steps of: generating a plurality of pilot signals, wherein the plurality of pilot signals comprises a plurality of orthogonal frequency-division multiplexed, OFDM, symbols that are orthogonally coded; generating a plurality of disjoint OFDM, sub-channel sets, wherein the plurality of disjoint OFDM sub-channel sets comprise disjoint, substantially orthogonal frequency-division multiplexed sub-channel sets; transmitting the plurality of pilot signals over a propagation channel between a transmitter unit and a plurality of receiver units, wherein the transmitter unit comprises at least one transmit antenna, each of the plurality of receiver units comprises at least one receive antenna, and the propagation channel comprises a plurality of sub-channels between the transmitter unit and the plurality of receiver units; transmitting at least one of the plurality of pilot signals on at least one of the plurality of disjoint OFDM sub-channel sets; receiving at least one of the plurality of pilot signals at each of the plurality of receiver units; determining a set of transmission characteristics for at least one of the plurality of sub-channels, wherein the step of determining the set of transmission characteristics uses at least one of the plurality of pilot signals received at each of the plurality of receiver units; reporting an information signal from each of the plurality of receiver units to the transmitter unit, wherein the information signal carries the set of transmission characteristics for at least one of the plurality of sub-channels; and optimizing a set of transmission parameters at the transmitter unit, based on the information signal. generating a plurality of pilot signals, wherein the plurality of pilot signals comprises a plurality of orthogonal frequency-division multiplexed, OFDM, symbols that are orthogonally coded; generating a plurality of disjoint OFDM, sub-channel sets, wherein the plurality of disjoint OFDM sub-channel sets comprise disjoint, substantially orthogonal frequency-division multiplexed sub-channel sets; transmitting the plurality of pilot signals over a propagation channel between a transmitter unit and a plurality of receiver units, wherein the transmitter unit comprises at least one transmit antenna, each of the plurality of receiver units comprises at least one receive antenna, and the propagation channel comprises a plurality of sub-channels between the transmitter unit and the plurality of receiver units; transmitting at least one of the plurality of pilot signals on at least one of the plurality of disjoint OFDM sub-channel sets; receiving at least one of the plurality of pilot signals at each of the plurality of receiver units; determining a set of transmission characteristics for at least one of the plurality of sub-channels, wherein the step of determining the set of transmission characteristics uses at least one of the plurality of pilot signals received at each of the plurality of receiver units; reporting an information signal from each of the plurality of receiver units to the transmitter unit, wherein the information signal carries the set of transmission characteristics for at least one of the plurality of sub-channels; and optimizing a set of transmission parameters at the transmitter unit, based on the information signal.