Patent ID: 8306137

Claim:
A data processing apparatus operable to map input symbols to be communicated onto a predetermined number of sub-carrier signals of an Orthogonal Frequency Division Multiplexed (OFDM) symbol, the data processing apparatus comprising: an interleaver operable to read-into a memory the predetermined number of data symbols for mapping onto the OFDM sub-carrier signals, and to read-out of the memory the data symbols for the OFDM sub-carriers to effect the mapping, the read-out being in a different order than the read-in, the order being determined from a set of addresses, with the effect that the data symbols are interleaved on the sub-carrier signals, and an address generator operable to generate the set of addresses, the addresses being generated for the input symbols to indicate the sub-carrier signals onto which the data symbols are to be mapped, the address generator comprising: a linear feedback shift register including a predetermined number of register stages and being operable to generate a pseudo-random bit sequence in accordance with a generator polynomial, a permutation circuit operable to receive the content of the shift register stages and to permute the bits present in the register stages in accordance with a permutation order to form an address of one of the OFDM sub-carriers, and a control unit operable in combination with an address check circuit to re-generate an address when a generated address exceeds a predetermined maximum valid address, wherein the predetermined maximum valid address is approximately five hundred, and the linear feedback shift register has eight register stages with a generator polynomial for the linear feedback shift register of R′ i [7 ]=R′ i-1 [0 ]⊕R′ i-1 [1 ]⊕R′ i-1 [5 ]⊕R′ i-1 [6] and the permutation order forms, with an additional bit, a nine bit address R i [n] for the i-th data symbol from the bit present in the n-th register stage R′ i [n] in accordance with the table: R′ i bit positions 7 6 5 4 3 2 1 0 R i bit positions 3 7 4 6 1 2 0 5.