Method and apparatus for multi-dimensionally encoding and decoding

A method of multi-dimensionally decoding a channel data stream of channel words into which user words of a user data stream are encoded, said channel data stream evolving in a one-dimensional direction of infinite extent, wherein:

• the NRZI channel symbols are transcoded into NRZ channel symbols by an operation reverse to a one-dimensional 1T-precoding operation including an integration modulo 2, said reverse operation comprising at least a differentiation operation, wherein an NRZ channel word comprises a sequence of NRZ channel symbols of NRZ channel bits having a one-dimensional interpretation along said one-dimensional direction and wherein states of an underlying finite-state-machine describing the characteristics of the multi-dimensional code are defined by NRZI channel bits of the previous channel word and by NRZ channel symbols of the current channel word, and
• the NRZ channel word is decoded into a user word by selecting said user word from a code table depending on said NRZ channel word and the next-state of said underlying finite-state-machine at which the next user word in said user data stream has been encoded, wherein said next-state of a current channel word of said underlying finite-state-machine is defined by NRZI channel bits of the current channel word and by NRZ channel symbols of the next channel word.

Apparatus for multi-dimensionally encoding a user data stream of user words into a channel data stream of channel words evolving in a one-dimensional direction of infinite extent, wherein:

• a mapping unit for encoding a user word into an NRZ channel word by selecting said NRZ channel word from a code table depending on said user word and the current state of an underlying finite-state-machine, wherein an NRZ channel word comprises a sequence of NRZ channel symbols of NRZ channel bits having a one-dimensional interpretation along said one-dimensional direction and wherein states of an underlying finite-state-machine describing the characteristics of the multi-dimensional code are defined by NRZI channel bits of the previous channel word and by NRZ channel symbols of the current channel word,
• a channel word conversion unit for transcoding the NRZ channel symbols into NRZI channel symbols by a one-dimensional 1T-precoding operation including an integration modulo 2, said 1T-precoding operation being carried out along said one-dimensional direction of infinite extent, and
• a state conversion unit for putting said finite-state-machine into a new state selected from said code table depending on said user word and the current state of said finite-state-machine together with encoding a user word into a channel word.