Abstract: An interleaver which allows the use of consecutive groups of codewords within a frame, where the maximum size of each codeword is constrained to be equal to or less than a certain maximum size. In accordance with required performance standards, i.e., the specification of a maximum number of data errors that the system is supposed to withstand, the interleaver is capable of limiting the number of errors which occur within a specific codeword to be less than the maximum number of errors that can be corrected by the particular coding scheme. The interleaver is able to achieve this result even for codewords of uneven length. The interleaver attempts to divide the total number of symbols to be transmitted in a frame into equal size codewords. If the codeword size cannot be made equal, then unequal size codewords are used, however, the difference in size between codewords cannot be greater than one symbol.