Abstract: Embodiments relate to a baseband processing apparatus and a baseband processing method based on orthogonal frequency-division multiplexing (OFDM). In order to solve the problem of high PAPR in OFDM systems, the baseband processing apparatus and method generate a plurality of data with different peak to average power ratios (PAPRs) by modifying bit representations of the frozen bits used by a polar code encoder, and then select the one of the plurality of data with the smallest PAPR as an OFDM signal.

Abstract: A decoding method for low density parity check (LDPC) code, used to decode an input signal into a correct codeword according to a predetermined LDPC matrix, is provided. The method includes performing a plurality of decoding attempts according to the LDPC matrix within a predetermined number of decoding attempts, the plurality of decoding attempts at least including a first decoding attempt with use of a first decoding schedule and a second decoding attempt with use of a second decoding schedule. The second decoding attempt is adjacently subsequent to the first decoding attempt. The first decoding schedule as a group is not included in the second decoding schedule.

Abstract: An encoding and decoding method of low-density parity-check code is disclosed. The method is following steps: a high rate check code is transferred to a check matrix having a protograph. The check matrix is extended to form an extended base matrix and is split to form a split base matrix. The extended base matrix and the split base matrix are respectively calculated to generate their decoding threshold by a protograph extrinsic information transfer chart. The base matrix with the lower decoding threshold is considered as a low rate base matrix. Repeating the above process until a stop condition is satisfied. The last low rate base matrix is expanded to form a parity check matrix. The transmission data is encoded and decoded by the parity check matrix.

Abstract: A decoding method of a LDPC comprises following steps. A first predetermined number of iterations of a messages-passing decoding algorithm are applied to a received signal vector, so as to attempt to decode a transmitted (or stored) codeword. Whether the decoding result converges to a valid codeword is determined by observing whether the decoding result makes all check nodes satisfied or not. When the decoding result does not converge to a valid codeword, the value of at least one of the variable nodes neighboring to one of the un-satisfied check node is be adjusted to a non-zero value, wherein the selected variable node is included in a trapping set. Then, a second predetermined number of iterations of the messages-passing decoding algorithm are applied to the updated decoding result to generate another one decoding result, and whether the other one decoding result converges to a valid codeword is checked.