Telefonaktiebolaget LM Ericsson (publ)
Method of determining sign of a calibration compensation

Abstract:

A method (20) of determining sign of a calibration compensation for use in an antenna system (10) is provided, the antenna system (10) comprising individually calibrated subarrays (2a, 2b). The method (20) comprises selecting (21) a set of antenna elements comprising two neighboring antenna elements of the first subarray (2a) and two neighboring antenna elements of the second subarray (2b); measuring (22): in a selected antenna element of the first subarray (2a) a first received signal Y.sub.31 as transmitted from the other selected antenna element of the first subarray (2a) and a second received signal Y.sub.34 as transmitted from the neighboring antenna element of the second subarray (2b), and in a selected antenna element of the second subarray (2b) a third received signal Y.sub.21 as transmitted from the other selected antenna element of the second subarray (2b) and a fourth received signal Y.sub.24 as transmitted from the neighboring antenna element of the first subarray (2a); calculating (23) for the first calibrated subarray (2a) a downlink compensation value .DELTA.t.sub.a and an uplink compensation value Ar.sub.a based on measurement values obtained from the measuring (22), each compensation value At.sub.a, Ar.sub.a having a positive and a negative solution; determining (24) a first compensation value estimate, k.sub.t, for downlink compensation and a second compensation value estimate, k.sub.r, for uplink compensation; and determining (25) the sign of the downlink compensation value At.sub.a and the uplink compensation value Ar.sub.a based on distance between the first compensation value estimate k.sub.t and the downlink compensation value, At.sub.a, and the distance between the second compensation value estimate, k.sub.r, and the uplink compensation value Ar.sub.a.