Determination of hardware impairment parameters for downlink channel state information estimation

Intra-array pilot measurements are performed with an antenna array of a MIMO transceiver. The antenna array comprises N transceive antennas. The antenna array is partitioned into K groups of antennas, G k , k = 1,..., K, wherein K ≥ 2, each group G k comprising N k antennas, A ki ,i = 1,..., N k , of the antenna array. For each k = 1,..., Κ, S k pilot measurements, M ks ,s = 1,..., S k , are performed, wherein S k ≥ 1 and wherein each pilot measurement M ks comprises transmitting simultaneously by each antenna A ki , i = 1,..., N k , of the group G k a pilot signal P kis and generating by each antenna A k'i' , i' = 1,..., N k' , of the other groups, G k ', k'≠ k, a received signal Y kk'i's by receiving the pilot signals Pkis transmitted by the antennas A ki , i = 1,..., N k . The measurements can be performed in a mode for detecting whether current hardware impairment parameters are valid or in a mode for updating the hardware impairment parameters.