Bandwidth allocation signalling

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.

2. The method of claim 1 , wherein the MU frame is an 80 MHz frame, the first bandwidth is 2 MHz, and the first RU is a middle 26 tones in between a first set of 484 tones of the MU frame and a second set of 484 tones of the MU frame.

3. The method of claim 2 , wherein the first RU Allocation Subfield includes a single bit to indicate that the first RU is not allocated to a station in the MU transmission,

wherein the first HE-SIG-B is included in a first 20 MHz of the MU frame,

wherein the first bandwidth is outside the first 20 MHz, and

wherein the first RU Allocation Subfield further indicates an allocation of RUs within the first 20 MHz.

4. The method of claim 3 , further comprising:

determining, by the AP, an allocation of RUs of a second 20 MHz of the MU frame; and

determining, by the AP, a value of a second RU Allocation Subfield according to the allocation of the RUs of the second 20 MHz and the single bit to indicate that the first RU is not allocated to a station in the MU transmission,

wherein generating the MU frame includes providing, in the second 20 MHz, a second HE-SIG-B field, the second HE-SIG-B field including the second RU Allocation Subfield.

5. The method of claim 1 , wherein the first bandwidth is 20 MHz and the first HE-SIG-B field is provided in the first bandwidth of the MU frame, the method further comprising:

determining, by the AP, an allocation of RUs of a second bandwidth of the MU frame, wherein the second bandwidth is 20 MHz;

determining, by the AP, a value of a second RU Allocation Subfield according to the allocation of the RUs of the second bandwidth,

wherein generating the MU frame includes providing, in the second bandwidth, a second HE-SIG-B field, the second HE-SIG-B field including the second RU Allocation Subfield.

6. The method of claim 5 , further comprising:

determining, by the AP, that a second RU of the second bandwidth is not allocated to a station in the MU transmission,

wherein the value of the second RU Allocation Subfield indicates that the second RU is not allocated.

7. The method of claim 1 , wherein the first bandwidth is 20 MHz, the first RU is a middle 2 MHz in the first bandwidth, the first HE-SIG-B field is provided in the first bandwidth of the MU frame, and values of one or more bits in the first RU Allocation Subfield, located in the first HE-SIG-B field, indicate that the first bandwidth is unassigned.