METHOD AND APPARATUS FOR DETERMINING A PRECODING MATRIX FOR PRECODING SYMBOLS TO BE TRANSMITTED TO A PLURALITY OF WIRELESS DEVICES.

摘要

A method for determining a precoding matrix (P CM) for precoding symbols (s) to be transmitted to a plurality of wireless devices by a node of a wireless communication system is described. The precoding matrix (P CM, P) comprises a precoding vector (p k) for each wireless device of a plurality of wireless devices and each precoding vector (p k) comprises a precoding element (ejθi,k) for each transmit antenna of a plurality of transmit antennas of the node. Further, each precoding element (ejθi,k) represents a phase shifter being able to shift a phase of a symbol to be transmitted through the corresponding transmit antenna to the corresponding wireless device by a phase angle. The method comprises calculating a plurality of interference strength indicators for different phase angles (θ). The different phase angles are applied successively to a precoding element (ejθi,k) of a precoding vector (p k) for the calculation of the interference strength indicators. An interference strength indicator is calculated based on a precoding matrix (P), comprising the precoding element (ejθi,k) considering the respective different phase angle (θ). Further, the method comprises selecting for the precoding element (ejθi,k) of the precoding vector (p k) a phase angle (θ) corresponding to a calculated interference strength indicator fulfilling a predefined interference strength criterion.