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. An optical transport network (OTN) apparatus comprising:
an Optical channel Transport Unit (OTUk) frame generator to generate OTUk frames;
a Forward Error Correction (FEC) encoder device, operatively coupled to receive and apply FEC encoding to data from the OTUk frames; and
a row de-interleaver device operatively coupled to the FEC encoder device to apply, to encoded data from the FEC encoder device, multiple permutation operations in respective different dimensions.
2. The apparatus of claim 1 , further comprising:
a row interleaver operatively coupled to the OTUk frame generator to apply, to the data in rows of the generated OTUk frames, multiple permutation operations in respective different dimensions,
wherein the FEC encoder device is operatively coupled to receive and apply FEC encoding to permuted data from the row interleaver,
wherein the multiple permutation operations of the row de-interleaver device are inverses of the multiple permutation operations of the row interleaver.
3. An optical transport network (OTN) system comprising:
a transmitter comprising the apparatus of claim 2 ; and
a receiver comprising:
an OTUk framer to delineate OTUk frames from signals received from the transmitter over an optical channel;
a receiver row interleaver operatively coupled to the OTUk framer to apply, to data in rows of the delineated OTUk frames, multiple permutation operations in respective different dimensions, the multiple permutation operations of the receiver row interleaver matching the multiple permutation operations of the row interleaver;
a FEC decoder, operatively coupled to the receiver row interleaver, to receive and apply FEC decoding to permuted data from the receiver row interleaver; and
a receiver row de-interleaver device operatively coupled to the FEC decoder to apply, to decoded data from the FEC decoder, multiple permutation operations in respective different dimensions, the multiple permutation operations of the receiver row de-interleaver device matching the multiple permutation operations of the row de-interleaver device.
4. The apparatus of claim 1 , wherein the row de-interleaver device comprising:
a first time varying permutation element receiving data stream, applying a first time varying permutation to the data stream, and filling a block interleaver row-by-row;
a second time varying permutation element reading data filled in the block interleaver column-by-column and applying a second time varying permutation to the read data; and
a controller controlling selection of a plurality of permutation maps in each of the first and second time varying permutation elements.
5. The apparatus of claim 4 , wherein the controller includes a counter generating a time varying control signal in response to a clock signal.
6. The apparatus of claim 5 , wherein each of the first and second time varying permutation elements includes a plurality of permutation stages, each of the plurality of permutation stages selecting one of two or more permutation maps in response to a corresponding value of the time varying control signal.
7. The apparatus of claim 6 , wherein each of the plurality of permutation stages includes a switch or a multiplexer.
8. An optical transport network (OTN) apparatus comprising:
an Optical channel Transport Unit (OTUk) framer to delineate OTUk frames from signals received over an optical channel;
a row interleaver device operatively coupled to the OTUk framer to apply, to data in rows of the delineated OTUk frames, multiple permutation operations in respective different dimensions; and
a Forward Error Correction (FEC) decoder device, operatively coupled to the row interleaver device, to receive and apply FEC decoding to permuted data from the row interleaver device.
9. The apparatus of claim 8 , further comprising:
a row de-interleaver device operatively coupled to the FEC decoder device to apply, to decoded data from the FEC decoder device, multiple permutation operations in respective different dimensions, the multiple permutation operations of the row de-interleaver device being inverses of the multiple permutation operations of the row interleaver device.
10. The apparatus of claim 8 , wherein the row interleaver device comprises:
a first time varying permutation element receiving data stream, applying a first time varying permutation to the data stream, and filling a block interleaver row-by-row;
a second time varying permutation element reading data filled in the block interleaver column-by-column and applying a second time varying permutation to the read data; and
a controller controlling selection of a plurality of permutation maps in each of the first and second time varying permutation elements.
11. The apparatus of claim 10 , wherein the controller includes a counter generating a time varying control signal in response to a clock signal.
12. The apparatus of claim 11 , wherein each of the first and second time varying permutation elements includes a plurality of permutation stages, each of the plurality of permutation stages selecting one of two or more permutation maps in response to a corresponding value of the time varying control signal.
13. The apparatus of claim 12 , wherein each of the plurality of permutation stages includes a switch or a multiplexer.