Transmission apparatus and transmission method for transmitting a control signal in a wireless communication system
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.
1. A transmission apparatus comprising:
a transmission signal generator which, in operation, generates a transmission signal that includes a legacy preamble, a non-legacy preamble and a data field, wherein the non-legacy preamble comprises a first non-legacy signal (SIG-A) field and a second non-legacy signal (SIG-B) field, the SIG-B field comprising a first channel field that corresponds to a first frequency subband and a second channel field that corresponds to a second frequency subband different from the first frequency subband, wherein the SIG-A field comprises a SIG-B compression subfield and a number of SIG-B symbols subfield, wherein
the number of SIG-B symbols subfield indicates a number of SIG-B symbols in the SIG-B field when the SIG-B compression subfield indicates that a full bandwidth containing the first frequency subband and the second frequency subband is not allocated for multi-user (MU) MIMO transmission, and
the number of SIG-B symbols subfield indicates a number of MU MIMO users when the SIG-B compression subfield indicates that the full bandwidth is allocated for MU MIMO transmission; and
a transmitter which, in operation, transmits the generated transmission signal.
2. The transmission apparatus according to claim 1 , wherein when the SIG-B compression subfield indicates that the full bandwidth is allocated for MU MIMO transmission, a plurality of user-specific subfields are split equitably between the first channel field and the second channel field.
3. The transmission apparatus according to claim 1 , wherein each of the first channel field and the second channel field comprises a user-specific field that includes multiple user-specific subfields, each user-specific subfield carrying information for a corresponding terminal station.
4. The transmission apparatus according to claim 1 , wherein when the SIG-B compression subfield indicates that the full bandwidth is allocated for the MU MIMO transmission, a common field that carries resource assignment information is not present in each of the first channel field and the second channel field.
5. The transmission apparatus according to claim 1 , wherein each of the first channel field and the second channel field includes a common field that carries resource assignment information when the SIG-B compression subfield indicates that the full bandwidth is not allocated for the MU MIMO transmission.
6. The transmission apparatus according to claim 1 , wherein
when the SIG-B compression subfield indicates that the full bandwidth is not allocated for MU MIMO transmission, each of the first channel field and the second channel field in the SIG-B field includes a common field that carries resource assignment information; and
when the SIG-B compression subfield indicates that the full bandwidth is allocated for MU MIMO transmission, the common field that carries resource assignment information is not present in each of the first channel field and the second channel field.
7. A transmission method comprising:
generating a transmission signal that includes a legacy preamble, a non-legacy preamble and a data field, wherein the non-legacy preamble comprises a first non-legacy signal (SIG-A) field and a second non-legacy signal (SIG-B) field, the SIG-B field comprising a first channel field that corresponds to a first frequency subband and a second channel field that corresponds to a second frequency subband different from the first frequency subband, wherein the SIG-A field comprises a SIG-B compression subfield and a number of SIG-B symbols subfield, wherein
the number of SIG-B symbols subfield indicates a number of SIG-B symbols in the SIG-B field when the SIG-B compression subfield indicates that a full bandwidth containing the first frequency subband and the second frequency subband is not allocated for multi-user (MU) MIMO transmission, and
the number of SIG-B symbols subfield indicates a number of MU MIMO users when the SIG-B compression subfield indicates that the full bandwidth is allocated for MU MIMO; and
transmitting the generated transmission signal.