Manifold calibration for a communication system

A method for performing direction of departure (DOD) manifold calibration, the method comprising the steps of:

• determining by a base station, an angle θ to a mobile unit, wherein the determination is made by a technique other than determining a direction of a signal received from the mobile unit;
• receiving by the base station, feedback from the mobile unit regarding a dominant downlink vector r(b), wherein b is a time index;
• determining, by the base station, calibration coefficients D based on the angle θ and dominant downlink vector r(b), wherein the step of determining the calibration coefficients D, comprises the steps of:
• determining W=diag(r(b));
• and
• determining D=diag({circumflex over (d)}b), where {circumflex over (d)}b=(WHW)−1WHa(θ), where a(θ) is
• an array manifold vector;
• and
• applying, by the base station, the calibration coefficients to downlink transmissions to the mobile unit.

An apparatus for performing direction of arrival (DOA) manifold calibration, the apparatus comprising:

• calibration circuitry having as an input, information on an angle θ to a mobile unit, an uplink transmission (Y(k,b)) from a mobile unit, wherein k is a subcarrier index and b is a time index, the calibration circuitry determining a dominant vector r(b) from the received uplink transmission, the calibration circuitry outputting calibration coefficients C(b) based on the angle θ and r(b) and wherein the calibration coefficients C(b) are computed by the calibration circuitry based on the angle θ and R(b)r(b) by:
• determining W=diag(r(b));
• and
• determining C(b)=diag(ĉb), where ĉb=(WHW)−1WHa(θ), where a(θ) is an array manifold vector;
• and
• multiplication circuitry applying the calibration coefficients to received uplink transmissions.

An apparatus for performing direction of departure (DOD) manifold calibration, the apparatus comprising:

• calibration circuitry receiving information on an angle θ to a mobile unit and receiving vector feedback from the mobile unit regarding a dominant downlink vector r(b), wherein b is a time index, the calibration circuitry outputting calibration coefficients D based on the angle θ and dominant downlink vector r(b) wherein the calibration coefficients D, are computed by the calibration circuitry by:
• determining W=diag(r(b));
• and
• determining D=diag({circumflex over (d)}b), where {circumflex over (d)}b=(WHW)−1WHa(θ), where a (θ) is an
• array manifold vector;
• and
• multiplication circuitry applying the calibration coefficients to downlink transmissions to the mobile unit.