Wireless transceiver station with performs multi-path reciprocity calibration with multiple reference antennas

A wireless transceiver station, comprising:

• M antennas connected to radio transceivers;
• and
• a processor, programmed to:
• designate an antenna of the M antennas as a target reference antenna;
• designate a subset of R antennas of the M antennas as reference antennas, where the target reference antenna is included in the subset, where R is at least two;
• for each antenna m of the M antennas other than the target reference antenna:
• define N distinct paths from the antenna m to the target reference antenna through zero or more of P distinct pairs of antennas (rr, rl) of the subset of R reference antennas, where P is at least one, where N for the antenna m is two or more;
• for at least each antenna pair (m, r) included in the N distinct paths for the M antennas:
• estimate an effective forward and backward channel response by sending calibration pilots forth and back between the antenna pair (m, r);
• and
• calculate a single-hop reciprocity coefficient estimate for the antenna pair (m, r) using the estimated effective forward and backward channel responses for the antenna pair (m, r);
• for each antenna pair (rr, rl) of the P distinct pairs of antennas (rr, rl) of the subset of R reference antennas:
• calculate one or more dual-hop reciprocity coefficient estimates for the antenna pair (rr, rl) through respective one or more antennas of the M antennas, where each respective antenna is distinct from rr and rl;
• and
• combine the single-hop reciprocity calibration coefficient estimate for the antenna pair (rr, rl) and the one or more dual-hop reciprocity calibration coefficient estimates for the antenna pair (rr, rl) to generate a combined reciprocity calibration coefficient estimate for the antenna pair (rr, rl);
• and
• for each antenna m of the M antennas:
• for each path of the N distinct paths for the antenna m, calculate a respective reciprocity coefficient estimate using:
• the combined reciprocity calibration coefficient estimates for each of the antenna pairs (rr, rl) included in the path;
• and
• the single-hop reciprocity coefficient estimate for the antenna pair (m, r), where antenna r is one of the antennas in antenna pair (rr, rl) included in the path;
• and
• combine the N respective reciprocity coefficient estimates to produce a final reciprocity coefficient estimate for antenna pair (m, target reference antenna).

A method, comprising:

• designating an antenna of M antennas of a wireless transceiver station as a target reference antenna;
• and
• for each antenna m of the M antennas other than the target reference antenna:
• defining N distinct paths from the antenna m to the target reference antenna through zero or more intermediate reference antennas of the M antennas, wherein N for the antenna m is two or more;
• wherein each of the N distinct paths has a distinct associated set of one or more antenna pairs of the M antennas;
• for each antenna pair of the sets of antenna pairs:
• estimating an effective forward and backward channel response by sending calibration pilots forth and back between the antenna pair;
• and
• calculating a reciprocity coefficient for the antenna pair using the estimated channel responses;
• for each path of the N distinct paths:
• calculating a reciprocity coefficient estimate using the reciprocity coefficients calculated for the set of antenna pairs associated with the path;
• and
• combining the N calculated reciprocity coefficient estimates to produce a final reciprocity coefficient estimate for antenna pair (m, target reference antenna).

A method, comprising:

• designating one antenna of the M antennas as a target reference antenna;
• designating a subset of R antennas of the M antennas as reference antennas, where the target reference antenna is included in the subset, where R is at least two;
• for each antenna m of the M antennas other than the target reference antenna:
• defining N distinct paths from the antenna m to the target reference antenna through zero or more of P distinct pairs of antennas (rr, rl) of the subset of R reference antennas, where P is at least one, where N for the antenna m is two or more;
• for at least each antenna pair (m, r) included in the N distinct paths for the M antennas:
• estimating an effective forward and backward channel response by sending calibration pilots forth and back between the antenna pair (m, r);
• and
• calculating a single-hop reciprocity coefficient estimate for the antenna pair (m, r) using the estimated effective forward and backward channel responses for the antenna pair (m, r);
• for each antenna pair (rr, rl) of the P distinct pairs of antennas (rr, rl) of the subset of R reference antennas:
• calculating one or more dual-hop reciprocity coefficient estimates for the antenna pair (rr, rl) through respective one or more antennas of the M antennas, where each respective antenna is distinct from rr and rl;
• and
• combining the single-hop reciprocity calibration coefficient estimate for the antenna pair (rr, rl) and the one or more dual-hop reciprocity calibration coefficient estimates for the antenna pair (rr, rl) to generate a combined reciprocity calibration coefficient estimate for the antenna pair (rr, rl);
• and
• for each antenna m of the M antennas:
• for each path of the N distinct paths for the antenna m, calculating a respective reciprocity coefficient estimate using:
• the combined reciprocity calibration coefficient estimates for each of the antenna pairs (rr, rl) included in the path;
• and
• the single-hop reciprocity coefficient estimate for the antenna pair (m, r), where antenna r is one of the antennas in antenna pair (rr, rl) included in the path;
• and
• combining the N respective reciprocity coefficient estimates to produce a final reciprocity coefficient estimate for antenna pair (m, target reference antenna).