Sounding and tone block allocation for orthogonal frequency division multiple access (ofdma) in wireless local area networks

Abstract

A first communication device transmits a null data packet (NDP) to multiple second communication devices. The NDP spans a channel frequency bandwidth. The first communication device receives a plurality of sounding feedback packets from the second communication devices. Each sounding feedback packet includes one or more signal-to-noise ratio (SNR) indicators corresponding to one or more respective groups of orthogonal frequency division multiplexing (OFDM) subcarriers, and the SNR indicators correspond to reception of the NDP at the plurality of second communication devices. Each sounding feedback packet in the plurality of sounding feedback packets includes a respective indication of OFDM subcarriers for which the sounding feedback packet includes SNR information, and at least one sounding feedback packet from among the plurality of sounding feedback packets does not include SNR information for all OFDM subcarriers via which the NDP was transmitted.

What is claimed is: 
     
         1 . A method for simultaneously communicating with multiple communication devices in a communication network, the method comprising:
 transmitting, by a first communication device, a null data packet (NDP) to a plurality of second communication devices, wherein the NDP spans a channel frequency bandwidth, and wherein the NDP is transmitted via a plurality of orthogonal frequency division multiplexing (OFDM) subcarriers that span the channel frequency bandwidth;   receiving, at the first communication device, a plurality of sounding feedback packets from the plurality of second communication devices,
 wherein each sounding feedback packet includes one or more signal-to-noise ratio (SNR) indicators corresponding to one or more respective groups of OFDM subcarriers from among the plurality of OFDM subcarriers, 
 wherein the SNR indicators correspond to reception of the NDP at the plurality of second communication devices, 
 wherein each sounding feedback packet in the plurality of sounding feedback packets includes a respective indication of OFDM subcarriers for which the sounding feedback packet includes SNR information, and 
 wherein at least one sounding feedback packet from among the plurality of sounding feedback packets does not include SNR information for all OFDM subcarriers via which the NDP was transmitted; 
   allocating, at the first communication device, respective sets of OFDM subcarriers to second communication devices in a group of second communication devices for an OFDMA communication, wherein the first communication device uses the received SNR indicators to allocate the sets of OFDM subcarriers; and   at least one of:
 transmitting, by the first communication device to the group of second communication devices, a downlink OFDMA transmission that includes respective data directed to the second communication devices in the group, wherein the respective data are transmitted via respective sets of OFDM subcarriers that were allocated to the second communication devices in the group, and 
 receiving, at the first communication device, an uplink OFDMA transmission from the group of second communication devices, wherein the uplink OFDMA transmission includes respective data from the second communication devices in the group, wherein the respective data are transmitted via respective sets of OFDM subcarriers that were allocated to the second communication devices in the group.