Transmission filter calculator, communication device and methods

A method for calculating at least a transmit filter for a communication from a transmit communication device comprising a plurality of antennas to a receive communication device out of a plurality of receive communication devices comprising a plurality of antennas via a multiple-input-multiple-output channel,

• wherein the method comprises iteratively determining transmit filters for a plurality of data streams, wherein a transmit filter is chosen in a given iteration such that the transmit filter chosen in the given iteration is orthogonal to one or more transmit filters chosen in one or more previous iterations, and such that a weighted or unweighted transmission rate acquirable using the transmit filter chosen in the given iteration is maximized, and
• wherein the transmit filter is chosen in dependence on a matrix product term which is based on a channel matrix describing MIMO channel characteristics between the transmit communication device and a currently considered one of the receive communication devices and on a distortion covariance matrix describing a noise, an inter-cell interference and an upper limit of an intra-cell interference.

A communication device for communicating with a transmit communication device in the presence of one or more interferer communication devices,

• wherein the communication device is configured to determine a channel matrix describing MIMO channel characteristics between the communication device and the transmit communication device, and to also determine one or more channel matrices describing MIMO channel characteristics between the communication device and the one or more interferer communication devices, and
• wherein the communication device is configured to determine a matrix product which is based on the channel matrix describing a MIMO channel between the communication device and the transmit communication device and on a distortion covariance matrix describing a noise, an inter-cell interference and an upper limit of an intra-cell interference, to acquire a product matrix, and
• wherein the communication device is configured to transmit the product matrix to the transmit communication device.