A method includes mapping, based on a first antenna mapping, a plurality of symbols to a plurality of antennas for transmitting a first data unit to a receiver, mapping, based on a first subcarrier mapping, the plurality of symbols to a plurality of subcarriers for transmitting the first data unit, and determining whether the receiver has successfully received the first data unit. The method also includes, in response to determining that the receiver has not successfully received the first data unit, (i) mapping, based on a second antenna mapping, the plurality of symbols to the plurality of antennas for transmitting a second data unit to the receiver, (ii) mapping, based on a different, second subcarrier mapping, the plurality of symbols to the plurality of subcarriers for transmitting the second data unit, and (iii) causing the second subcarrier mapping to be communicated to the receiver.