According to an example method performed in a High Speed Downlink Packet Access (HSDPA) environment, a first device generates a High Speed Downlink Shared Channel (HS-DSCH) data frame that includes a plurality of blocks of packet data units. A first block of the plurality of blocks includes packet data units of a first length, and a second block of the plurality of blocks includes packet data units of a different, second length. The first device transfers the HS-DSCH data frame to a second device. The HS-DSCH data frame further includes, for each block of the plurality of blocks, a first information element that indicates a length of the one or more packet data units in the each block, and a second information element that indicates a quantity of packet data units in the each block.