A method and equipment 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 (e j ¸ i , k ) for each transmit antenna of a plurality of transmit antennas of the node. Further, each precoding element (e j ¸ i,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 (¸). The different phase angles are applied successively to a precoding element (e j ¸ i,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 (e j¸i,k ) considering the respective different phase angle (¸). Further, the method comprises selecting for the precoding element (e j ¸ i,k ) of the precoding vector ( p k ) a phase angle (¸) corresponding to a calculated interference strength indicator fulfilling a predefined interference strength criterion.