Data processing apparatus and method for interleaving and deinterleaving data

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, wherein the predetermined number of sub-carrier signals are determined in accordance with one of a plurality of operating modes and the data symbols are divided into first sets of data symbols and second sets of data symbols, the data processing apparatus comprising:

• demodulator circuitry configured to detect an indication of the operating mode,
• a deinterleaver configured to perform an odd deinterleaving process which deinterleaves the first sets of data symbols from the sub-carrier signals of first OFDM symbols into an output data stream and an even deinterleaving process which deinterleaves the second sets of data symbols from the sub-carrier signals of second OFDM symbols into the output data stream, and
• a deinterleaver memory, the odd deinterleaving process comprising:
• writing the first sets of data symbols recovered from the sub-carrier signals of the first OFDM symbols into the deinterleaver memory in accordance with an order defined by a permutation code, and
• reading out the first sets of data symbols from the deinterleaver memory in a accordance with a sequential order into the output data stream,
• the even deinterleaving process comprising:
• writing the second sets of data symbols recovered from the sub-carrier signals of the second OFDM symbols into the deinterleaver memory in accordance with a sequential order, and
• reading out the second sets of data symbols from the deinterleaver memory in accordance with an order defined by the permutation code into the output data stream, such that while data symbols from the first set are being read from locations in the deinterleaver memory, data symbols from the second set can be written to the locations just read from and when data symbols from the second set are being read from the locations in the deinterleaver memory, the data symbols from a following first set can be written to the locations just read from, wherein
• when the number of data symbols which can be carried by the sub-carriers of an OFDM symbol in one or more of the plurality of operating modes is half or less than half of the number of data symbols, which can be carried in an operating mode which provides the most number of data bearing sub-carrier signals per OFDM symbol, the data processing apparatus is configured to deinterleave the data symbols from both the first and second sets in accordance with the odd deinterleaving process from the first and second OFDM symbols and
• the data processing apparatus is further configured to change the permutation code according to the indication of the operating mode.

A method of mapping 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 comprising first sets of data symbols and second sets of data symbols, the method comprising:

• detecting by circuitry an indication of the operating mode;
• deinterleaving, in accordance with an odd deinterleaving process which deinterleaves the first sets of data symbols from the sub-carrier signals of first OFDM symbols into the output data stream and in accordance with an even deinterleaving process which deinterleaves the second sets of data symbols from the sub-carrier signals of second OFDM symbols into the output data stream,
• the odd deinterleaving process comprising:
• writing the first sets of data symbols recovered from the sub-carrier signals of the first OFDM symbols into an deinterleaver memory in accordance with an order defined by a permutation code, and
• reading out the first sets of data symbols from the deinterleaver memory in a accordance with a sequential order into the output data stream,
• the even deinterleaving process comprising:
• writing the second sets of data symbols recovered from the sub-carrier signals of the second OFDM symbols into the deinterleaver memory in accordance with a sequential order, and
• reading out the second sets of data symbols from the deinterleaver memory in accordance with an order defined by the permutation code into the output data stream, such that while data symbols from the first set are being read from locations in the deinterleaver memory, data symbols from the second set can be written to the locations just read from and when data symbols from the second set are being read from the locations in the deinterleaver memory, the data symbols from a following first set can be written to the locations just read from, wherein
• when the number data symbols which can be carried by the sub-carriers of an OFDM symbol in one or more of the plurality of operating modes is half or less than half of the number of data symbols, which can be carried in an operating mode which provides the most number of data bearing sub-carrier signals per OFDM symbol, the deinterleaving comprises deinterleaving the data symbols from both the first and second sets in accordance with the odd deinterleaving process from the first and second OFDM symbols, and
• changing the permutation code according to the indication of the operating mode.