When building a sub-frame for a wireless transmission that distributes the data over multiple simultaneous sub-channels, fragmenting the data to fit into the sub-frame may leave wasted space in the sub-frame because the minimum allowable size of the fragments leaves gaps. To increase overall throughput, these gaps may be wholly or partly filled in with another type of data that has smaller minimum size fragments. In some embodiments, the sub-frame may use orthogonal frequency division multiple access (OFDMA) protocols, and the two data types may be classified as automatic repeat request (ARQ)-enabled and non-ARQ-enabled data.