| CPC H04L 5/0057 (2013.01) [H04B 7/0417 (2013.01); H04B 7/0452 (2013.01); H04L 5/0007 (2013.01); H04L 5/0023 (2013.01); H04L 5/0039 (2013.01); H04L 5/0055 (2013.01); H04W 84/12 (2013.01)] | 22 Claims |

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1. A system, comprising a plurality of access points (APs) configured to:
generate a null data packet (NDP);
transmit at least a portion of the NDP to one or more stations (STAs) via a first subset of a plurality of sub-channels of one or more communication channels, wherein a second subset of the plurality of sub-channels is unused by the transmission;
receive a signal from at least one STA of the one of the one or more STAs that is based on the at least one STA processing the at least the portion of the NDP that is received via the first subset of the plurality of sub-channels of the one or more communication channels; and
process a portion of the signal from the at least one STA while ignoring another portion of the signal from the at least one STA that corresponds to at least one of the second subset of the plurality of sub-channels of the one or more communication channels.
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