Patent attributes
A communication device generates a first data unit that spans a first bandwidth, and transmits the first data unit during a transmit opportunity (TXOP) to at least one other communication device. The communication device subsequently determines, based on respective values of TXOP duration fields included in respective physical layer (PHY) preambles of one or more data units previously transmitted during the TXOP, whether a second bandwidth of a second data unit to be transmitted by the communication device during the TXOP can be greater than the first bandwidth of the first data unit. In response to determining that the second bandwidth of the second data unit can be greater than the first bandwidth of the first data unit, the communication device generates the second data unit to span the second bandwidth greater than the first bandwidth, and transmits the second data unit during the TXOP.