Coding apparatus, coding method and recording medium having coded program recorded therein, and decoding apparatus, decoding method and recording medium having decoded program recorded therein

A decoding method for carrying out decoding of codes subjected to serially concatenated code modulation by a coding method comprising:

• a first coding step for carrying out coding whose code rate is k/(k+1) with respect to data of k-bit input;
• a first interleaving step for interleaving order of bits constituting data comprising a bit series of (k+1) pieces coded by said first coding step;
• a coding processing step for carrying out at least one or more processes including a second coding step for carrying out coding whose code rate is 1 with respect to data of (k+1) bit input and a second interleaving step for interleaving order of bits constituting data comprising a bit series of (k+1) pieces coded by said second coding step;
• a third coding step for carrying out coding whose code rate is 1 with respect to data of (k+1) bit processed by said coding processing step and input;
• and a mapping step for mapping data of (k+1) bits coded by said third coding step to a transmission symbol of predetermined modulation system;
• said decoding method comprising:
• first soft-output decoding, corresponding to said third coding step, using a reception word which is a soft-input input, and priori probability information with respect to information bits of (k+1) bits which is a soft-input input;
• carrying out at least one or more processes including a first deinterleaving step, a second soft-output decoding step and a third interleaving step with respect to data of (k+1) bits of a soft-input input;
• a second deinterleaving step for rearranging data of (k+1) bits of a soft-input input processed by said carrying out step input so that a bit array of data of (k+1) bits rearranged by said first interleaving step is returned to a bit array of data of (k+1) bits coded by said first coding step;
• third soft-output decoding, corresponding to said first coding step, using priori probability information with respect to code bits of (k+1) bits which are a soft-input output rearranged by said second deinterleaving step, and priori probability information with respect to information bits of (k+1) bits which are a soft-input input;
• and
• fourth interleaving order of bits constituting data comprising a bit series of (k+1) pieces of a soft-input output produced by said third soft-output decoding step on the basis of the same exchange position information as that of said first interleaving step;
• said first deinterleaving step rearrange data of (k+1) bits of a soft-input input so that a bit array of data of (k+1) bits rearranged by said second interleaving step is returned to a bit array of data of (k+1) bits coded by said second coding step;
• said second soft-output decoding step being provided corresponding to of said at least one or more second coding steps to carry out soft-output decoding using priori probability information with respect to code bits of (k+1) bits which are a soft-input output rearranged by said first deinterleaving step, and priori probability information with respect to information bits of (k+1) bits which are a soft-input input;
• and
• said third interleaving step interleaving order of bits constituting data comprising a bit series of (k+1) pieces of a soft-input output produced by of said at least one or more second soft-output decoding steps on the basis of the same exchange position information as that of said second interleaving step.

A recording medium having recorded a decoded program capable of being controlled by a computer to perform a decoding method for carrying out decoding of codes subjected to serially concatenated code modulation by a coding method comprising:

• a first coding step for carrying out coding whose code rate is k/(k+1) with respect to data of k-bit input;
• a first interleaving step for interleaving order of bits constituting data comprising a bit series of (k+1) pieces coded by said first coding step;
• a coding processing step for carrying out at least one or more processes including a second coding step for carrying out coding whose code rate is 1 with respect to data of (k+1) bit input and a second interleaving step for interleaving order of bits constituting data comprising a bit series of (k+1) pieces coded by said second coding step;
• a third coding step for carrying out coding whose code rate is 1 with respect to data of (k+1) bit processed by said coding processing step and input;
• and a mapping step for mapping data of (k+1) bits coded by said third coding step to a transmission symbol of predetermined modulation system;
• said decoding method comprising:
• first soft-output decoding, corresponding to said third coding step, using a reception word which is a soft-input input, and priori probability information with respect to information bits of (k+1) bits which is a soft-input input;
• carrying out at least one or more processes including a first deinterleaving step, a second soft-output decoding step and a third interleaving step with respect to data of (k+1) bits of a soft-input input;
• a second deinterleaving step for rearranging data of (k+1) bits of a soft-input processed by said carrying out step input so that a bit array of data of (k+1) bits rearranged by said first interleaving step is returned to a bit array of data of (k+1) bits coded by said first coding step;
• third soft-output decoding, corresponding to said first coding step, using priori probability information with respect to code bits of (k+1) bits which are a soft-input rearranged by said second deinterleaving step, and priori probability information with respect to information bits of(k+1) bits which are a soft-input input;
• and
• fourth interleaving order of bits constituting data comprising a bit series of (k+1) pieces of a soft-input output produced by said third soft-output decoding step on the basis of the same exchange position information as that of said first interleaving step;
• said first deinterleaving step rearrange data of (k+1) bits of a soft-input input so that a bit array of data of (k+1) bits rearranged by said second interleaving step is returned to a bit array of data of (k+1) bits coded by said second coding step;
• said second soft-output decoding step being provided corresponding to of said at least one or more second coding steps to carry out soft-output decoding using priori probability information with respect to code bits of (k+1) bits which are a soft-input output rearranged by said first deinterleaving step, and priori probability information with respect to information bits of (k+1) bits which are a soft-input input;
• and
• said third interleaving step interleaving order of bits constituting data comprising a bit series of (k+1) pieces of a soft-input produced by of said at least one or more second soft-output decoding steps on the basis of the same exchange position information as that of said second interleaving step.