1. A method comprising: demultiplexing a bit stream into a first block and a second block; convolutionally coding the first block; block coding the second block; applying the block coded second block to a function module to apply one of a plurality of different functions to form a third block at an output of the module; mapping the convolutionally coded first block and the third block to a modulation constellation for transmission, the mapping resulting in different constellation points depending on the applied function.