A preamble, a first portion of a data payload, a midamble, and a second portion of the data payload of a single data unit are generated. The midamble is to be transmitted subsequent to transmission of the first portion of the data payload and prior to transmission of the second portion of the data payload. The midamble includes an indication of at least one characteristic of the data payload such as an indication of a size of the second portion of the data payload, or whether or not the data payload includes one or more other portions in addition to the first and second portions. A network interface of a communication device is configured to generate the preamble, the first and second portions of the data payload, and the midamble.