Methods for Opportunistic Multi-User Beamforming in Collaborative MIMO-SDMA

A base station for determining weighting and combining vectors for a plurality of subscriber stations, the base station comprising:

• a plurality of receive antennas;
• a processor;
• and
• a memory medium storing program instructions, wherein the program instructions, when executed by the processor, cause the base station to implement:
• determining channel conditions for each of the plurality of subscriber stations, wherein each of the subscriber stations includes a plurality of transmit antennas, wherein, for each of the subscriber stations, the corresponding channel conditions include a representation of a plurality of channel gains between the subscriber station and the plurality of receive antennas;
• for each of the subscriber stations, determining the corresponding weighting vector and the corresponding combining vector for the subscriber station, wherein the corresponding weighting vector includes a complex weight for each transmit antenna of the subscriber station, and the corresponding combing vector includes a complex weight for each receive antenna of the base station, wherein the weighting vectors and combining vectors for the subscriber stations are determined jointly;
• for each of at least one or more of the subscriber stations, sending the corresponding weighting vector to the subscriber station for use in uplink transmission to the base station.

A non-transitory memory medium for operating a base station in order to determine weighting and combining vectors for a plurality of subscriber stations, wherein the base station includes a plurality of receive antennas, wherein the memory medium stores program instructions, wherein the program instructions, when executed by a processor, cause the base station to implement:

• determining channel conditions for each of the plurality of subscriber stations, wherein each of the subscriber stations includes a plurality of transmit antennas, wherein, for each of the subscriber stations, the corresponding channel conditions include a representation of a plurality of channel gains between the subscriber station and the plurality of receive antennas;
• for each of the subscriber stations, determining the corresponding weighting vector and the corresponding combining vector for the subscriber station, wherein the corresponding weighting vector includes a complex weight for each transmit antenna of the subscriber station, and the corresponding combing vector includes a complex weight for each receive antenna of the base station, wherein the weighting vectors and combining vectors for the subscriber stations are determined jointly;
• for each of at least one or more of the subscriber stations, sending the corresponding weighting vector to the subscriber station for use in uplink transmission to the base station.