Patent ID: 8175142

Claim:
A data processing apparatus configured to map data symbols received from a predetermined number of sub-carrier signals of Orthogonal Frequency Division Multiplexed (OFDM) symbols into an output data stream, the predetermined number of sub-carrier signals being determined in accordance with one of a plurality of operating modes and the data symbols including first sets of data symbols and second sets of data symbols, the data processing apparatus comprising: an address generator, a controller, and a de-interleaver memory, the controller being configured, when operating in accordance with an even de-interleaving process to read out from the de-interleaver memory a first set of the data symbols into the output data stream using addresses generated by the address generator, to write into the de-interleaver memory a second set of the data symbols received from the sub-carrier signals of an even OFDM symbol in accordance with a sequential order of addresses, and the controller is configured in accordance with an odd de-interleaving process, to read out from the de-interleaver memory a first set of the data symbols into the output data stream using read addresses determined in accordance with a sequential order, and to write into the de-interleaver memory a second set of the data symbols received from the sub-carrier signals of an odd OFDM symbol at addresses generated by the address generator, such that while data symbols from the first set are being read from locations in the de-interleaver memory, data symbols from the second set can be written to the locations just read from, wherein the number of the sub-carriers that are available from a previous odd or even OFDM symbol is different from the number of the sub-carriers that are available from a current OFDM symbol, and the controller is configured to determine before reading out the first data symbols from the de-interleaver memory, whether the read address is valid for the previous OFDM symbol, and to determine before writing the second data symbols into the de-interleaver memory, whether the write address is valid for the current OFDM symbol.