Methods for opportunistic multi-user beamforming in collaborative mimo-sdma

A method for designing beamforming vectors for a collaborative space division multiple access system, comprising:

• for each one of a plurality of subscriber stations, determining an array of channel conditions;
• where the each one of the plurality of determined arrays comprises a representation of a plurality of channel gains corresponding to one or more transmit antennas and one or more receive antennas;
• ranking the plurality of determined arrays according to at least a first criterion;
• and
• designing a beamforming vector for each subscriber station based at least in part on the ranking.

A base station apparatus that determines beamforming vectors for a plurality of subscriber stations, comprising:

• an array of transmit and receive antennas;
• a processor;
• and
• a computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program configured to, when executed on the processor:
• determine an array of channel conditions for each one of the plurality of subscriber stations, each one of the plurality of determined arrays comprising a representation of a plurality of channel gains between the array of transmit and receive antennas and the each one of the plurality of subscriber stations;
• rank the plurality of determined arrays according to a first criterion;
• and
• determine a beamforming vector for each subscriber station, based at least in part on the ranking.

A method for determining beamforming vectors for a collaborative space division multiple access system, comprising:

• for each one of a plurality of subscriber stations, determining an array of channel conditions, each one of the plurality of determined arrays comprising a representation of a plurality of channel gains corresponding to one or more transmit antennas and one or more receive antennas;
• separating the plurality of subscriber stations into at least a first and second subset of subscribers;
• determining a first plurality of beamforming vectors for each subscriber station of the first subset;
• and
• subsequently thereafter determining a second plurality of beamforming vectors for each subscriber station of the second subset.

Mobile wireless apparatus configured to receive signals from a base station having an array of transmit and receive antennas, the mobile apparatus comprising:

• a processor;
• and
• transceiver apparatus, the transceiver apparatus comprising at least one antenna and configured to:
• transmit at least one signal which permits determination of a plurality of channel gains associated with the mobile apparatus, the plurality of channel gains being part of an array of channel conditions associated with the mobile wireless apparatus, the plurality of channel gains representing channel gains between the array of transmit and receive antennas of the base station and mobile wireless apparatus;
• and
• receive at least one signal transmitted from the base station, the at least one signal having been transmitted using a beamforming vector particularly determined for the mobile apparatus, the beamforming vector being one of a plurality of beamforming vectors having been determined by the base station for the mobile wireless device and respective ones of other mobile wireless apparatus.