Time varying data permutation apparatus and methods
Multiple data permutation operations in respective different dimensions are used to provide an overall effective data permutation using smaller blocks of data in each permutation than would be used in directly implementing the overall permutation in a single permutation operation. Data that has been permuted in one permutation operation is block interleaved, and the interleaved data is then permuted in a subsequent permutation operation. A matrix transpose is one example of block interleaving that could be applied between permutation operations.
1. A data transmission system comprising:
an interleaver configured to apply, to data frames, multiple permutation operations in respective different dimensions to generate a first time-varying stream;
a Forward Error Correction (FEC) encoder configured to encode the first time-varying stream to generate an encoded stream; and
a de-interleaver configured to apply, to the encoded stream, multiple permutation operations in respective different dimensions to generate a second time-varying stream.
2. The data transmission system of claim 1 wherein the interleaver comprises a block interleaver configured to generate an interleaved data stream based on the data frames, the first-time varying stream being generated based on the interleaved data stream.
3. The data transmission system of claim 1 further comprising a frame generator for generating the data frames.
4. The data transmission system of claim 3 wherein the interleaver is configured to process the data frames.
5. The data transmission system of claim 1 wherein the de-interleaver is configured to generate an encoded output data stream based on the second-time varying stream.
6. The data transmission system of claim 1 wherein the de-interleaver comprises a time-varying permutation element for performing inverse permutation of the multiple permutation operations applied to the data frames.
7. The data transmission system of claim 1 wherein the first time-varying stream is generated at a plurality of permutation stages.
8. The data transmission system of claim 7 further comprising a controller coupled to the plurality of permutation stages.
9. The data transmission system of claim 1 wherein the interleaver is configured to apply a 64-bit permutation process.
10. A data receiver system comprising:
an interleaver configured to apply, to encoded data frames, multiple permutation operations in respective different dimensions to generate a first time-varying stream;
a forward error correction (FEC) decoder configured to decode the first time-varying stream to generate a decoded stream; and
a de-interleaver configured to apply, to the decoded stream, multiple permutation operations in respective different dimensions to generate a second time-varying stream.
11. The data receiver system of claim 10 wherein the interleaver comprises a block interleaver configured to generate an interleaved data stream based on the encoded data frames, the first-time varying stream being generated based on the interleaved data stream.
12. The data receiver system of claim 10 wherein the de-interleaver comprises a de-interleaver configured to de-interleave the second time-varying stream.
13. The data receiver system of claim 10 further comprising a framer for generating the encoded data frames.
14. The data receiver system of claim 13 wherein the framer is configured to process data received from an optical channel.
15. The data receiver system of claim 10 wherein the de-interleaver comprises a time-varying permutation element for performing inverse permutation of the multiple permutation operations applied to the encoded data frames.
16. The data receiver system of claim 10 wherein the interleaver comprises a plurality of permutation stages.
17. The data receiver system of claim 16 wherein the interleaver further comprises a controller coupled to the plurality of permutation stages.
18. A data communication system comprising:
a transmitter configured to apply, to data frames, multiple permutation operations in respective different dimensions to generate a first time-varying stream, to encode the first time-varying stream to generate an encoded stream, to apply, to the encoded stream, multiple permutation operations in respective different dimensions to generate a second time-varying stream, and to transmit the second time-varying stream;
a data communication channel for transmitting the second time-varying stream; and
a receiver configured to receive the second time-varying stream and to process the second time-varying stream.
19. The data transmission system of claim 18 wherein the data communication channel comprises an optical communication channel.
20. The data communication system of claim 18 wherein the transmitter is configured to generate the data frames, the first time-varying stream being generated based on the data frames.