8. The method of claim 7 , wherein the secondary station uses a coding scheme during the second mode which generates a code word that is a punctured version of the code word that would be generated by the coding scheme used during the first mode.
9. The method of claim 8 , wherein the second mode is operable at a plurality of different information rates and by the coding scheme for a lower information rate generating a code word that is a truncated version of the code word generated for a higher information rate.