Interleaving/de-interleaving using compressed bit-mapping sequences
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorDayong Chen
Life of this patent
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Abstract
A method of mapping input bit positions in an input sequence to output bit positions in an output sequence uses compressed mapping sequences stored in memory derived from a predetermined mapping function. The mapping function is decompressed into periodic component functions that are used to generate the compressed mapping sequences. Each compressed mapping sequence comprises a plurality of partial mapping values that represent one period of a corresponding component function or group of component functions. Partial mapping values are selected from each compressed mapping sequence based on a bit index of the current input bit and summed or otherwise combined to get an output index.
Claims28
A method implemented by a communication device of reordering bits for channel coding or channel decoding by said communication device, the method comprising:
- storing in memory compressed mapping sequences derived from periodic component functions of a predetermined mapping function, each compressed mapping sequence comprising a plurality of pre-computed partial mapping values derived by evaluating said periodic component functions over one period;
- for each input bit in an input bit sequence, selecting partial mapping values from said compressed mapping sequences stored in memory based on an input index of the input bit;
- for each input bit in the input bit sequence, calculating an output index for the input bit based on said selected partial mapping values;
- and
- for each input bit in the input bit sequence, mapping the input bit to its corresponding output bit position in an output bit sequence based on the corresponding output index.
A mapping circuit for reordering bits for channel coding or channel decoding by a communication device, the mapping circuit comprising:
- memory to store compressed mapping sequences derived from periodic component functions of a predetermined mapping function, each compressed mapping sequence comprising a plurality of pre-computed partial mapping values derived by evaluating said periodic component functions over one period;
- a decompression unit to select, for each input bit in an input bit sequence, partial mapping values from each compressed mapping sequence based on a corresponding bit index for the input bit, and to calculate, for each input bit, corresponding output indexes for each said input bit to generate a decompressed mapping sequence;
- and
- a mapping unit to map each input bit in said input bit sequence to its corresponding output bit position based on the corresponding output index.
A computer readable media with a computer-executable instructions stored thereon for causing a processor in a communication device to reorder bits for channel coding or channel decoding by said communication device, said computer-executable instructions comprising instructions for:
- selecting, for each input bit in an input bit sequence, partial mapping values from compressed mapping sequences stored in memory based on a corresponding input index of the input bit, each compressed mapping sequence comprising a plurality of pre-computed partial mapping values derived by evaluating a periodic component function of said mapping function over one period;
- calculating, for each input bit, an output index for the input bit based on said selected partial mapping values to generate a decompressed mapping sequence;
- and
- mapping each input bit to an output bit position based on a corresponding output index.
Dependencies are inferred from the claim text.