Patent ID: 8891592

Claim:
A method for processing a preamble of a control physical layer (PHY) data unit received via a communication channel, wherein the preamble includes a short training field (STF) and a channel estimation field (CEF), the method comprising: receiving the STF that includes a plurality of instances of a spreading sequence; determining if the plurality of instances of the spreading sequence consists of a first number of instances; processing the preamble according to a first format if the plurality of instances of the spreading sequence consists of the first number of instances, wherein the first format corresponds to a default mode of the control PHY data unit transmission; processing the preamble according to a second format if the plurality of instances of the spreading sequence consists of a second number of instances, wherein the second number is greater than the first number, and wherein the second format corresponds to an extended preamble mode of the control PHY data unit transmission; and activating a timer when the first one of the plurality of spreading sequences is received, wherein the timer is associated with an expiration period equal to a duration of the first number of instances, and wherein determining if the plurality of spreading sequences consists of the first number of instances includes checking whether all of the spreading sequences in the plurality of spreading sequences have been received upon expiration of the timer.