Downlink signaling in a high efficiency wireless local area network (wlan)

A first communication device, comprising:

• a wireless network interface device including one or more integrated circuit (IC) devices configured to:
• generate a physical layer (PHY) preamble, including:
• generating a first signal field that includes i) an identifier of a wireless network in which the PHY data unit is being transmitted, and ii) an indication of a bandwidth of the PHY data unit, and
• generating a second signal field that includes i) a common block of information bits having information for multiple second communication devices and ii) a plurality of user blocks of information bits, each user block having information for a respective one of the multiple second communication devices, wherein:
• the common block includes a frequency resource unit allocation field having a length that varies depending on a bandwidth of the PHY data unit, wherein the frequency resource unit allocation field defines a plurality of frequency resource units corresponding to a PHY payload of the PHY data unit,
• the user blocks respectively correspond to frequency resource units defined by the frequency resource unit allocation field,
• each user block includes an identifier of a second communication device to which the user block corresponds, and includes an indication of a modulation and coding scheme (MCS) used in the corresponding frequency resource unit, and
• generating the second signal field comprises:
• encoding the common block as a first encoded block,
• grouping at least some of the user blocks as groups of two user blocks, and
• encoding each group of two user blocks as a respective second encoded block to allow the multiple second communication devices to efficiently decode the second signal field;
• wherein the one or more IC devices are further configured to:
• generate the PHY data portion of the PHY data unit having the plurality of frequency resource units defined by the frequency resource unit allocation field in the second signal field, wherein generating the PHY data portion includes using the MCSs, indicated by the plurality of user blocks, in the frequency resource units.