A system including a physical layer module and a control module. The physical layer module is configured to generate a first clear channel assessment for a first sub-channel of a communication channel and generate a second clear channel assessment for a second sub-channel of the communication channel. The first clear channel assessment indicates whether the first sub-channel is free or busy. The second clear channel assessment indicates whether the second sub-channel is free or busy. The control module is configured to, in response to the second sub-channel being busy, extend a duration of the second clear channel assessment by a predetermined period of time, and transmit data via (i) only the first sub-channel or (ii) both the first sub-channel and the second sub-channel based on (a) the first clear channel assessment, (b) the second clear channel assessment, and (c) the extended duration of the first clear channel assessment.