Determining channel availability for orthogonal frequency division multiple access operation

An apparatus, comprising:

• a network interface device associated with a first communication device, wherein the network interface device is implemented using one or more integrated circuits (ICs), wherein the one or more ICs are configured to:
• receive, from a second communication device, a first data unit via one or more communication channels, wherein the first data unit includes an indication of a first set of one or more sub-channels allocated to the first communication device, and wherein the first data unit is configured to prompt the first communication device to transmit channel availability information as part of a subsequent orthogonal frequency division multiple access (OFDMA) transmission;
• determine channel availability information for the one or more communication channels;
• and
• when the network interface device determines that at least one of the communication channels among the one or more communication channels is idle,
• transmit a second data unit to the second communication device as part of the OFDMA transmission, wherein the second data unit includes the channel availability information, and wherein the second data unit is transmitted in one or more allocated sub-channels, among the first set of one or more sub-channels allocated to the first communication device.

A method for communication between a first communication device and a plurality of second communication devices via one or more communication channels, the method comprising:

• allocating, at the first communication device, a plurality of sub-channels, among the one or more communication channels, to the plurality of second communication devices to generate first allocation information that indicates a first allocation of the plurality of sub-channels to the plurality of second communication devices;
• generating, at the first communication device, a first physical layer (PHY) data unit that includes the first allocation information, wherein the first PHY data unit also includes information configured to prompt the plurality of second communication devices to provide channel availability information in response to the first PHY data unit;
• transmitting, by the first communication device, the first PHY data unit to the plurality of second communication devices via the one or more communication channels;
• receiving, at the first communication device, first uplink orthogonal frequency division multiple access (OFDMA) transmissions from at least some second communication devices in the plurality of second communication devices in response to the first PHY data unit, wherein the first uplink OFDMA transmissions include respective channel availability information from respective second communication devices;
• and
• allocating, at the first communication device, the plurality of sub-channels to the at least some second communication devices using the respective channel availability information to generate second allocation information that indicates a second allocation of the plurality of sub-channels to the at least some second communication devices.

An apparatus, comprising:

• a network interface device associated with a first communication device, wherein the network interface device is implemented using one or more integrated circuits (ICs), wherein the one or more ICs are configured to:
• allocate a plurality of sub-channels, among one or more communication channels, to a plurality of second communication devices to generate first allocation information that indicates a first allocation of the plurality of sub-channels to the plurality of second communication devices;
• generate a first physical layer (PHY) data unit that includes the first allocation information, wherein the first PHY data unit also includes information configured to prompt the plurality of second communication devices to provide channel availability information in response to the first PHY data unit;
• transmit the first PHY data unit to the plurality of second communication devices via the one or more communication channels;
• receive first uplink orthogonal frequency division multiple access (OFDMA) transmissions from at least some second communication devices in the plurality of second communication devices in response to the first PHY data unit, wherein the first uplink OFDMA transmissions include respective channel availability information from respective second communication devices;
• and
• allocate the plurality of sub-channels to the at least some second communication devices using the respective channel availability information to generate second allocation information that indicates a second allocation of the plurality of sub-channels to the at least some second communication devices.

A method, comprising:

• receiving, at a communication device, a physical layer (PHY) data unit from a second communication device, wherein the PHY data unit indicates one or more sub-channels of one or more communication channels in connection with a subsequent orthogonal frequency division multiple access (OFDMA) transmission to the second communication device;
• using, at the first communication device, an energy signal level measurement made during a time period prior to reception of the PHY data unit to determine channel availability information;
• and
• using, at the communication device, the channel availability information in conjunction with an OFDMA transmission to be performed in response to the PHY data unit.

An apparatus, comprising:

• a network interface device associated with a first communication device, wherein the network interface device is implemented using one or more integrated circuits (ICs), and wherein the one or more ICs are configured to:
• receive a physical layer (PHY) data unit from a second communication device, wherein the PHY data unit indicates one or more sub-channels of one or more communication channels in connection with a subsequent orthogonal frequency division multiple access (OFDMA) transmission to the second communication device;
• use an energy signal level measurement made during a time period prior to reception of the PHY data unit to determine channel availability information;
• and
• use the channel availability information in conjunction with an OFDMA transmission to be performed in response to the PHY data unit.