Transmission apparatus and transmission method with simplified rate conversion

A transmission apparatus comprising:

• encoding means for encoding for error correction bits for information symbols in which information bits and extra bits for transmission control are assigned to low-order bits and dummy bits are assigned to high-order bits, so as to generate bits for parity symbols such that the number of bits per information symbol is equal to the number of bits per parity symbol, and subjects the high-order bits for parity symbols to symbol conversion;
• frame constructing means for constructing a transmission frame by combining low-order bits for information symbols, low-order bits for parity symbols and bits subjected to symbol conversion by said encoding means;
• transmitting means for subjecting the transmission frame constructed by said frame constructing means to M-ary quadrature amplitude modulation and outputting a resultant modulated signal to a communication channel;
• receiving means for subjecting the modulated signal received via the communication channel to M-ary quadrature amplitude demodulation and outputting a resultant received frame;
• frame decomposing means for establishing frame synchronization by referring to the extra bits included in the received frame output from said receiving means and decomposing the received frame into bits corresponding to information symbols and bits corresponding to parity symbols;
• and
• decoding means for subjecting the bits corresponding to parity symbols and output from said frame decomposing means to inverse symbol conversion and identifying the bits for information symbols by estimation based on the bits subjected to inverse symbol conversion and the bits corresponding to information symbols and output from said frame decomposing means.

A transmission method comprising the steps of:

• encoding for error correction bits for information symbols in which information bits are assigned to low-order bits and dummy bits are assigned to high-order bits, so as to generate bits for parity symbols such that the number of bits per information symbol is equal to the number of bits per parity symbol, and subjecting the high-order bits for parity symbols to symbol conversion;
• constructing a transmission frame by combining low-order bits for information symbols, low-order bits for parity symbols, bits subjected to symbol conversion by said encoding means and extra bits for transmission control;
• subjecting the transmission frame to M-ary quadrature amplitude modulation and outputting a resultant modulated signal to a communication channel;
• subjecting the modulated signal received via the communication channel to M-ary quadrature amplitude demodulation and outputting a resultant received frame;
• establishing frame synchronization by referring to the extra bits included-in the received frame and decomposing the received frame into bits corresponding to information symbols and bits corresponding to parity symbols;
• and
• subjecting the bits corresponding to parity symbols to inverse symbol conversion and identifying-the bits for information symbols by estimation based on the bits subjected to inverse symbol conversion and the bits corresponding to information symbols.

A transmission method comprising the steps of:

• encoding for error correction bits for information symbols in which information bits and extra bits for transmission control are assigned to low-order bits and dummy bits are assigned to high-order bits, so as to generate bits for parity symbols such that the number of bits per information symbol is equal to the number of bits per parity symbol, and subjects the high-order bits for parity symbols to symbol conversion;
• constructing a transmission frame by combining low-order bits for information symbols, low-order bits for parity symbols and bits subjected to symbol conversion in;
• subjecting the transmission frame to M-ary quadrature amplitude modulation and outputting a resultant modulated signal to a communication channel;
• subjecting the modulated signal received via the communication channel to M-ary quadrature amplitude demodulation and outputting a resultant received frame;
• establishing frame synchronization by referring to the extra bits included in the received frame and decomposing the received frame into bits corresponding to information symbols and bits corresponding to parity symbols;
• and
• subjecting the bits corresponding to parity symbols to inverse symbol conversion and identifying the bits for information symbols by estimation based on the bits subjected to inverse symbol conversion and the bits corresponding to information symbols.