Data processing apparatus and methods

摘要

A data processing apparatus is arranged in operation to recover data bits from data symbols received from a predetermined number of sub-carrier signals of Orthogonal Frequency Division Multiplexed (OFDM) symbols and to form an output bit stream. The predetermined number of sub-carrier signals of the OFDM symbols is determined in accordance with one of a plurality of operating modes. The data processing apparatus includes a symbol de-interleaver, a de-mapping unit, an inverse permuter and an LDPC decoder. The symbol de-interleaver recovers first sets of data symbols from first OFDM symbols in accordance with an odd-interleaving process and second sets of data symbols from second OFDM symbols in accordance with an even interleaving process, and forms an output symbol stream from the first and second sets of data symbols. The de-mapping unit generates from the data symbols of the output symbol stream parity interleaved Low Density Parity Check (LDPC) encoded data bits by converting each of the data symbols of the output symbol stream into data bits in accordance with a modulation scheme. The inverse permuter performs an inverse permutation process to effect a reverse of a permutation process applied to the parity interleaved LDPC encoded data bits to permute the LDPC encoded data bits and the LDPC decoder is adapted to perform LDPC decoding on the LDPC encoded data bits on which the inverse permutation process has been performed to form the output data bits. When in one of the plurality of operating modes in which the number of sub-carriers per OFDM symbol provides half or less than half a maximum number of sub-carriers in the OFDM symbols of any of the operating modes, the data processing apparatus is operable to de-interleave the data symbols for both first and second sets from the first and second OFDM symbols sets in accordance with the odd interleaving process. The data processing apparatus can therefore communicate data bits via OFDM symbols of, for example DVB-T2 or DVB-C2.