Method and a device for decoding slice codes
AssigneeFrance Telecom
InventorsMatthieu Arzel, Fabrice Seguin, Cyril Lahuec
Life of this patent
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Abstract
A method and a device (20) for decoding a frame capable of being split into p sub-frames each consisting of k information symbols, a first n−k redundant symbols and a last n−k redundant symbols. The decoding process uses two individual decoders (21, 23) which concurrently produce extrinsic data (Extr1i, Extr2i) respectively concerning information symbols and interleaved information symbols. The values of the extrinsic data (Extr1i, Extr2i) are refined by cross-feedback of said data to the input of the decoders (21, 23).
Claims9
A method for iterative analog decoding of a frame that can be split into p sub-frames each made up of k information symbols, a first n−k redundant symbols, and a last n−k redundant symbols, where n and k are two particular numbers, wherein for one iteration in effecting a succession of steps such that for a step i, i varying from 1 to a maximum of p, the method includes first and second sequences of steps,
- A. wherein the first sequence comprises the steps of:
- (i) decoding by a first decoder the k information symbols (Systi) of the ith sub-frame and the first n−k redundant symbols (Y1i) of that same sub-frame to produce k extrinsic information symbols (Extr1i);
- (ii) storing in a first analog memory at a memory location depending on the step i the k preceding extrinsic information symbols (Extr1i);
- (iii) interleaving all data stored in the first analog memory;
- and
- (iv) injecting the interleaved data into the input of a second decoder to refine its decoding;
- and
- B. wherein at least a portion of the second sequence is performed concurrently with at least a portion of the first sequence, and the second sequence comprises the steps of:
- (i) interleaving the information symbols of all the sub-frames (Syst1, Syst2,. . . , Systp);
- (ii) decoding by the second decoder the k information symbols (Π(Syst)i) resulting from the interleaving and set from the ((i−1)×k+1)th position and the last n−k redundant symbols (Y2i) of the ith sub-frame to produce k extrinsic information symbols (Extr2i);
- (iii) storing in a second memory at a memory location depending on the step i the k extrinsic information symbols (Extr2i) produced by the second decoder;
- (iv) de-interleaving all data stored in the second memory;
- and
- (v) injecting the de-interleaved data into the input of the first decoder to refine its decoding.
A device for analog decoding of a frame that can be split into p sub-frames each made up of k information symbols, a first n−k redundant symbols, and a last n−k redundant symbols, where n and k are two particular numbers, comprising:
- a first decoder for decoding the k information symbols of the ith sub-frame and the first n−k redundant symbols of that same sub-frame, i varying from 1 to a maximum of p, and for producing k extrinsic information symbols (Extr1i);
- first means for interleaving all the information symbols of all the sub-frames;
- a second decoder for decoding concurrently with the first decoder the k information symbols set from the ((i−1)×k+1)th position and coming from the first interleaver means and the last n−k redundant symbols of the ith sub-frame and for producing k extrinsic information symbols (Extr2i);
- a first analog memory having a capacity at least equal to the overall size of the p×k extrinsic information symbols and second interleaver means for interleaving all data stored in the first memory, at a break-in position between an output of the first decoder and an input of the second decoder;
- a second analog memory having a capacity at least equal to the overall size of the p×k extrinsic information symbols and de-interleaver means for de-interleaving all data stored in the second memory, at a break-in position between an output of the second decoder which produces k extrinsic information symbols and an input of the first decoder;
- multiplexer means at the output of the first decoder for routing the k extrinsic information symbols (Extr1i) of an ith sub-frame coming from the first decoder at an input of the first memory to a memory location depending on each sub-frame;
- multiplexer means at the output of the second decoder for routing the k extrinsic information symbols (Extr2i) of an ith sub-frame coming from the second decoder at an input of the second memory to a memory location depending on each sub-frame;
- multiplexer means at the output of the second interleaver means for routing the k extrinsic information symbols coming from the second interleaver means and set from the ((i−1)×k+1)th position at the input of the second decoder;
- and
- multiplexer means at the output of the de-interleaver means for routing the k extrinsic information symbols coming from the de-interleaver means and set from the ((i−1)×k+1)th position at the input of the first decoder.
Dependencies are inferred from the claim text.