Iq imbalance estimation using broadcast signals

A method for determining an imbalance parameter for an in-phase path and a quadrature-phase path of a receiver, the method comprising:

• for each of a plurality of subcarrier pairs, adding a first symbol received over a first subcarrier of the subcarrier pair with a complex conjugate of a second symbol received over a second subcarrier of the subcarrier pair to form a statistic;
• solving for channel estimates using the statistic formed for each of the plurality of subcarrier pairs and using known values of the first and second symbols received over each of the plurality of subcarrier pairs;
• and
• solving for an imbalance parameter using the channel estimates and the first and second symbols received over each of the plurality of subcarrier pairs,
• wherein the first and second subcarriers of each of the plurality of subcarrier pairs are located at equal distances from a direct current (DC) subcarrier and on opposite sides of the DC subcarrier.

An apparatus comprising:

• an adder module configured to add, for each of a plurality of subcarrier pairs, a first symbol received over a first subcarrier of the subcarrier pair with a complex conjugate of a second symbol received over a second subcarrier of the subcarrier pair to form a statistic,
• a channel estimator configured to estimate channels using the statistic formed for each of the plurality of subcarrier pairs and known values of the first and second symbols received over each of the plurality of subcarrier pairs;
• and
• an imbalance estimator configured to estimate a gain and phase imbalance using the channel estimates and the first and second symbols received over each of the plurality of subcarrier pairs.