Directional MIMO antenna

A system comprising:

• a transmit subsystem, comprising two or more transmit antennas,
• arranged in a training mode to transmit a first training signal solely from a first transmit antenna at a first time, and to transmit a second training signal solely from a second transmit antenna at a second time, and
• also arranged in an operating mode to transmit two different signals from the first and second antennas at the same time;
• a receive subsystem comprising
• a plurality of directional receive antennas,
• a plurality of combining circuits connected to the plurality of receive antennas, each combining circuit providing an azimuth output and an elevation output;
• a plurality of receiver circuits, each connected to a respective one of the combining circuits, and
• arranged in the training mode to
• operate the combining circuits to scan the directional receive antennas, and to produce a first set of receive training signals indicative of a first azimuth (φA) and first elevation (ϕA) output signals when the first transmit antenna is active;
• and
• operate the combining circuits to scan the directional receive antennas, and to produce a second set of receive training signals indicative of a second azimuth (φB) and second elevation (ϕB) output signals when the second transmit antenna is active;
• and
• arranged in the operating mode to
• operating the combining circuits to provide azimuth and elevation operating output signals;
• a signal processor, for
• in the training mode, for deriving an azimuth-spatial, elevation-spatial, and temporal-frequency dependent transfer function for each of the first and second set of receive training signals;
• and
• wherein the signal processor is further for,
• in the operating mode,
• using the transfer functions as two or more matched filters for
• determining a first region of coherence for signals emitted from the first one of the transmit antennas, TA, formed around azimuth and elevation angles (φA, ϕA) and
• determining a second a region of coherence for signals emitted from the second one of the transmit antennas, TB, formed around azimuth and elevation angles (φB, ϕB), and thus
• providing azimuth-spatial and elevation-spatial multiplexing, to thereby enable the transmit subsystem to transmit independent signals at the same time over the same frequencies.