A wireless communication apparatus which participates in wireless communication involving an antenna array, comprising: processing circuitry (701, 702, 703, 704) configured to receive, from a target communication apparatus for the wireless communication apparatus, a signal including antenna array geometry information of the target communication apparatus and a training sequence signal; determine geometry configuration of the antenna array of the target communication apparatus based on the signal; estimate channel characteristic of a channel from the target communication apparatus to the wireless communication apparatus based on the training sequence signal; and determine, based on the geometry configuration of the antenna array and channel estimation result, channel feedback information indicating the channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus, wherein the antenna array geometry information indicates at least one of geometry arrangement of antenna elements in the antenna array, spacing between the antenna elements, and antenna polarization direction; and wherein the processing circuitry estimates short-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus based on the training sequence signal, and estimates long-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus based on the short-term channel characteristic and the geometry configuration of the antenna array of the target communication apparatus; wherein the processing circuitry determines, based on short-term channel estimation values for a plurality of antenna pairs having the same relative geometry relationship in the antenna array, long-term channel information estimation value for at least one of the plurality of antenna pairs, in order to estimate the long-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus, wherein each antenna pair includes a first antenna element and a second antenna element, and there is the same geometry relationship between the first antenna element and the second antenna element included in each of the plurality of antenna pairs having the same relative geometry relationship in the antenna array. processing circuitry (701, 702, 703, 704) configured to receive, from a target communication apparatus for the wireless communication apparatus, a signal including antenna array geometry information of the target communication apparatus and a training sequence signal; determine geometry configuration of the antenna array of the target communication apparatus based on the signal; estimate channel characteristic of a channel from the target communication apparatus to the wireless communication apparatus based on the training sequence signal; and determine, based on the geometry configuration of the antenna array and channel estimation result, channel feedback information indicating the channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus, wherein the antenna array geometry information indicates at least one of geometry arrangement of antenna elements in the antenna array, spacing between the antenna elements, and antenna polarization direction; and wherein the processing circuitry estimates short-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus based on the training sequence signal, and estimates long-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus based on the short-term channel characteristic and the geometry configuration of the antenna array of the target communication apparatus; wherein the processing circuitry determines, based on short-term channel estimation values for a plurality of antenna pairs having the same relative geometry relationship in the antenna array, long-term channel information estimation value for at least one of the plurality of antenna pairs, in order to estimate the long-term channel characteristic of the channel from the target communication apparatus to the wireless communication apparatus, wherein each antenna pair includes a first antenna element and a second antenna element, and there is the same geometry relationship between the first antenna element and the second antenna element included in each of the plurality of antenna pairs having the same relative geometry relationship in the antenna array.