Provided is a transmission apparatus including a transmission signal generator which, in operation, generates a transmission signal that includes a legacy preamble, a non-legacy preamble and a data field. The non-legacy preamble comprises a first signal field and a second signal field. The first signal field comprises a second signal field compression subfield and a number of second signal field symbols subfield. The second signal field symbols subfield indicates a number of second signal field symbols when the second signal field compression subfield indicates that a full bandwidth containing first and second frequency subbands is not allocated for multi-user (MU) MIMO transmission. The number of second signal field symbols indicates a number of MU MIMO users when the second signal field compression subfield indicates that the full bandwidth is allocated for MU MIMO transmission. The transmission apparatus includes a transmitter which, in operation, transmits the generated transmission signal.