1. An error correction encoding apparatus characterized in that said error correction encoding apparatus comprises:
a first error correction encoding means for generating a first inspection signal sequence for a first information signal sequence and a second information signal sequence requiring more intense error protection than the first information signal sequence;
a transmitting interleaving means for changing element order of said second information signal sequence;
a second error correction encoding means for generating a second inspection signal sequence for the second information signal sequence changed in order by said transmitting interleaving means; and
a transmitting means for transmitting an encoded signal including said first and second information signal sequences and said first and second inspection signal sequences onto a transmission channel.', 'a first error correction encoding means for generating a first inspection signal sequence for a first information signal sequence and a second information signal sequence requiring more intense error protection than the first information signal sequence;', 'a transmitting interleaving means for changing element order of said second information signal sequence;', 'a second error correction encoding means for generating a second inspection signal sequence for the second information signal sequence changed in order by said transmitting interleaving means; and', 'a transmitting means for transmitting an encoded signal including said first and second information signal sequences and said first and second inspection signal sequences onto a transmission channel.

2. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 1, characterized in that said error correction decoding apparatus comprises:
a first error correction decoding means for conducting error correction decoding on the first and second information signal sequences included in said received encoded signal, on the basis of the first inspection signal sequence included in said encoded signal, and outputting first and second decoded information signal sequences;
a receiving interleaving means for changing element order of the second decoded information signal sequence output from said first error correction decoding means;
a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction; and
a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order.', 'a first error correction decoding means for conducting error correction decoding on the first and second information signal sequences included in said received encoded signal, on the basis of the first inspection signal sequence included in said encoded signal, and outputting first and second decoded information signal sequences;', 'a receiving interleaving means for changing element order of the second decoded information signal sequence output from said first error correction decoding means;', 'a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction; and', 'a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order.

3. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 1, characterized in that said error correction decoding apparatus comprises:
a receiving interleaving means for changing element order of the second decoded information signal sequence included in the received encoded signal;
a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence;
a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order; and
a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said receiving de-interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting the first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction.', 'a receiving interleaving means for changing element order of the second decoded information signal sequence included in the received encoded signal;', 'a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence;', 'a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order; and', 'a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said receiving de-interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting the first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction.

4. An error correction decoding apparatus according to claim 2 or 3, characterized in that said first and second error correction decoding means has an iterative decoding function of iterating the error correction decoding processing between them at least once.

5. An error correction decoding apparatus according to claim 4, characterized in that said error correction decoding apparatus further comprises an iteration control means for determining number of times of iteration according to at least one of a demanded error correction capability and a permitted processing delay amount, and setting the determined number of times of iteration into said first and second error correction decoding means.

6. An error correction decoding apparatus according to claim 4, characterized in that said error correction decoding apparatus further comprises, on an input side of said first and second error correction decoding means, a normalization means for normalizing a signal level of each of signal sequences or signal blocks to be input to said first and second error correction decoding means, on the basis of a level of the received encoded signal.

7. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 1, characterized in that said error correction decoding apparatus comprises:
a first error correction decoding means for conducting error correction decoding on the first and second information signal sequences included in said received encoded signal, on the basis of the first inspection signal sequence included in said encoded signal, and outputting first and second decoded information signal sequences;
a second error correction decoding means for conducting interleaving on the second decoded information signal sequence output from said first error correction decoding means, then conducting error correction decoding on the second decoded information signal sequence thus interleaved, on the basis of the second inspection signal sequence included in said received encoded signal, thereby yielding the second decoded information signal sequence further subjected to the error correction, conducting de-interleaving on the second decoded information signal sequence, and outputting the second decoded information signal sequence thus interleaved;
a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and
a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', 'a first error correction decoding means for conducting error correction decoding on the first and second information signal sequences included in said received encoded signal, on the basis of the first inspection signal sequence included in said encoded signal, and outputting first and second decoded information signal sequences;', 'a second error correction decoding means for conducting interleaving on the second decoded information signal sequence output from said first error correction decoding means, then conducting error correction decoding on the second decoded information signal sequence thus interleaved, on the basis of the second inspection signal sequence included in said received encoded signal, thereby yielding the second decoded information signal sequence further subjected to the error correction, conducting de-interleaving on the second decoded information signal sequence, and outputting the second decoded information signal sequence thus interleaved;', 'a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and', 'a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', '8. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 1, characterized in that said error correction decoding apparatus comprises:
a second error correction decoding means for conducting interleaving on the second decoded information signal sequence included in the received encoded signal, then conducting error correction decoding on the second information signal sequence thus interleaved, on the basis of the second inspection signal sequence included in the received encoded signal, thereby yielding a second decoded information signal sequence, conducting de-interleaving on said second decoded information signal sequence, and outputting the second decoded information signal sequence thus interleaved;
a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said second error correction decoding means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting the first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction;
a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and
a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', 'a second error correction decoding means for conducting interleaving on the second decoded information signal sequence included in the received encoded signal, then conducting error correction decoding on the second information signal sequence thus interleaved, on the basis of the second inspection signal sequence included in the received encoded signal, thereby yielding a second decoded information signal sequence, conducting de-interleaving on said second decoded information signal sequence, and outputting the second decoded information signal sequence thus interleaved;', 'a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said second error correction decoding means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting the first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction;', 'a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and', 'a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', '9. An error correction encoding apparatus for conducting error correction encoding on a first information signal sequence and a second information signal sequence requiring more intense error protection than the first information signal sequence, and transmitting the encoded first information signal sequence and second information signal sequence, characterized in that said error correction encoding apparatus comprises:
a transmitting interleaving means for changing element order of said second information signal sequence;
a first error correction encoding means for generating a first inspection signal sequence for the second information signal sequence changed in order by said transmitting interleaving means and said first information signal sequence;
a second error correction encoding means for generating a second inspection signal sequence for said second information signal sequence; and
a transmitting means for transmitting an encoded signal including said first and second information signal sequences and said first and second inspection signal sequences onto a transmission channel.', 'a transmitting interleaving means for changing element order of said second information signal sequence;', 'a first error correction encoding means for generating a first inspection signal sequence for the second information signal sequence changed in order by said transmitting interleaving means and said first information signal sequence;', 'a second error correction encoding means for generating a second inspection signal sequence for said second information signal sequence; and', 'a transmitting means for transmitting an encoded signal including said first and second information signal sequences and said first and second inspection signal sequences onto a transmission channel.', '10. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 9, characterized in that said error correction decoding apparatus comprises:
a second error correction decoding means for conducting error correction decoding on the second information signal sequence included in the received encoded signal, on the basis of the second inspection signal sequence included in said encoded signal, and outputting a second decoded information signal sequence;
a receiving interleaving means for changing element order of the second decoded information signal sequence output from said second error correction decoding means;
a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting a first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction; and
a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order.', 'a second error correction decoding means for conducting error correction decoding on the second information signal sequence included in the received encoded signal, on the basis of the second inspection signal sequence included in said encoded signal, and outputting a second decoded information signal sequence;', 'a receiving interleaving means for changing element order of the second decoded information signal sequence output from said second error correction decoding means;', 'a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting a first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction; and', 'a receiving de-interleaving means for restoring the second decoded information signal sequence output from said second error correction decoding means, to the original element order.', '11. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 9, characterized in that said error correction decoding apparatus comprises:
a receiving interleaving means for changing element order of the second information signal sequence included in the received encoded signal;
a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting first and second decoded information signal sequences;
a receiving de-interleaving means for restoring the second decoded information signal sequence output from said first error correction decoding means, to the original element order; and
a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said receiving de-interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction.', 'a receiving interleaving means for changing element order of the second information signal sequence included in the received encoded signal;', 'a first error correction decoding means for conducting error correction decoding on the second decoded information signal sequence changed in order by said receiving interleaving means and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting first and second decoded information signal sequences;', 'a receiving de-interleaving means for restoring the second decoded information signal sequence output from said first error correction decoding means, to the original element order; and', 'a second error correction decoding means for conducting error correction decoding on the second decoded information signal sequence output from said receiving de-interleaving means, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction.', '12. An error correction decoding apparatus according to claim 10 or 11, characterized in that said first and second error correction decoding means has an iterative decoding function of iterating the error correction decoding processing between them at least once.', '13. An error correction decoding apparatus according to claim 12, characterized in that said error correction decoding apparatus further comprises an iteration control means for determining number of times of iteration according to at least one of a demanded error correction capability and a permitted processing delay amount, and setting the determined number of times of iteration into said first and second error correction decoding means.', '14. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 9, characterized in that said error correction decoding apparatus comprises:
a first correction decoding means for conducting error correction decoding on the second information signal sequences included in the received encoded signal, on the basis of the second inspection signal sequence included in said encoded signal, and outputting a second decoded information signal sequence;
a second correction decoding means for conducting error correction decoding on a signal sequence obtained by conducting interleaving on the second decoded information signal sequence output from said second error correction decoding means, and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, thereby yielding a first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction, conducting de-interleaving on the second decoded information signal sequence, and outputting the first decoded information signal sequence and the second decoded information signal sequence thus interleaved;
a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and
a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', 'a first correction decoding means for conducting error correction decoding on the second information signal sequences included in the received encoded signal, on the basis of the second inspection signal sequence included in said encoded signal, and outputting a second decoded information signal sequence;', 'a second correction decoding means for conducting error correction decoding on a signal sequence obtained by conducting interleaving on the second decoded information signal sequence output from said second error correction decoding means, and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, thereby yielding a first decoded information signal sequence and the second decoded information signal sequence further subjected to the error correction, conducting de-interleaving on the second decoded information signal sequence, and outputting the first decoded information signal sequence and the second decoded information signal sequence thus interleaved;', 'a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and', 'a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', '15. An error correction decoding apparatus for receiving and decoding the encoded signal transmitted from the error correction encoding apparatus according to claim 9, characterized in that said error correction decoding apparatus comprises:
a first error correction decoding means for conducting error correction decoding on a signal sequence obtained by conducting interleaving on the second decoded information signal sequence included in the received encoded signal, and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting first and second decoded information signal sequence;
a second error correction decoding means for conducting de-interleaving the second decoded information signal sequence output from said first error correction decoding means, then conducting error correction decoding on the second decoded information signal sequence thus de-interleaved, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction;
a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and
a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', 'a first error correction decoding means for conducting error correction decoding on a signal sequence obtained by conducting interleaving on the second decoded information signal sequence included in the received encoded signal, and the first information signal sequence included in said received encoded signal, on the basis of the first inspection signal sequence included in said received encoded signal, and outputting first and second decoded information signal sequence;', 'a second error correction decoding means for conducting de-interleaving the second decoded information signal sequence output from said first error correction decoding means, then conducting error correction decoding on the second decoded information signal sequence thus de-interleaved, on the basis of the second inspection signal sequence included in said received encoded signal, and outputting the second decoded information signal sequence further subjected to the error correction;', 'a third error correction decoding means for iterating error correction decoding processing between said first error correction decoding means and said second error correction decoding means at least once, and outputting the first and second decoded information signal sequences thus subjected to iterative decoding; and', 'a selection means for causing the error correction decoding processing using only the first error correction decoding means, the error correction decoding processing using the first and second error correction decoding means, and the error correction decoding processing using the first, second, and third error correction decoding means to be selectively executed, on the basis of at least one of a transmission channel state and a property of the transmitted information signal sequences.', '16. An error correction encoding apparatus according to claim 1 or 9, characterized in that unimportant information requiring a predetermined transmission quality is assigned to the first information signal sequence, and important information requiring a higher transmission quality than the first information signal sequence is assigned to the second information signal sequence.', '17. An error correction encoding apparatus according to claim 1 or 9, characterized in that information transmitted by using a first transmission scheme having a predetermined intensity against transmission errors is assigned to the first information signal sequence, and information transmitted by using a second transmission scheme having an intensity against transmission errors lower than that of the first transmission scheme is assigned to the second information signal sequence.']