1. A method implemented by an Access Point (AP) for performing a Multi-User (MU) transmission, the method comprising:determining, by the AP, an allocation of Resource Units (RUs) of a first bandwidth of an MU frame, including determining that a first RU of the MU frame is not allocated to a station in the MU transmission;
determining, by the AP, a value of a first RU Allocation Subfield according to the allocation of the RUs of the MU frame, the value of the first RU Allocation Subfield indicating that the first RU is not allocated;
generating, by the AP, a first High Efficiency Signal B (HE-SIG-B) field, wherein generating the first HE-SIG-B field comprises providing the first RU Allocation Subfield in a common info field of the first HE-SIG-B field and providing a plurality of user-specific subfields in the first HE-SIG-B field;
generating, by the AP, the MU frame, wherein generating the MU frame includes providing the first HE-SIG-B field in the MU frame; and
transmitting, by the AP, the MU frame over a wireless channel,
wherein the first RU Allocation Subfield provides an indication of a number of user-specific subfields in the first HE-SIG-B field.