particular since the ap has transmitted the sounding ppdu simultaneously to the sta 1 the sta 2 the sta 3 and the sta 4 each sta can performs mcs estimation by considering interference generated by a spatial stream corresponding to the sounding ppdu transmitted to another sta an mcs feedback sequence identifier may be included in the mrq transmitted by the ap to the stas however when the ap transmits the mrq simultaneously to the respective stas the mcs feedback sequence identifier is set to the same value this implies that an mcs feedback to be responded by the stas corresponds to the same mcs feedback request in this case the mcs feedback requester sets the same mcs feedback sequence identifier to stas for performing multi user transmission so as to effectively manage mcs feedback reports and so as to decrease waste of identifier space for the mcs feedback sequence identifier the mcs feedback sequence identifier may be included in a link adaptation control subfield if the mrq has the same mcs feedback sequence identifier an mcs feedback sequence identifier of an mcs feedback transmitted by each sta also has the same value therefore when an ap i e an mcs feedback requester receives a plurality of mcs feedbacks having the same mcs feedback sequence identifier it can be seen that these values are mcs values estimated by the respective stas corresponding to multi user transmissions simultaneously performed the mrq may include an mcs feedback order the.