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AssigneeKoninklijke Philips Electronics N.V.
InventorsWillem Marie Julia Marcel Coene, Andries Pieter Hekstra, Hiroyuki Yamagishi, Makoto Noda
Estimating the term…
Presently known d=1 codes have long trains consisting of consecutive 2T runs and an overall high frequency of occurrence of the shortest 2T runs that reduce the performance of the bit detector By using a code with an MTR constraint of 2 an improvement in the bit detection is achieved. A code constructed in a systematic way that provides an MTR constraint of 2 is presented. A variation of such a code is disclosed where one sub-code is used, where coding states are divided into coding classes and where code words are divided into code word types. Then, for a given sub-code, an code word of type t can be concatenated with an code word of the next sub-code if said subsequent code word of said next sub-code belongs to one of coding states of the coding class with index Tmax+1 t. In the code according to the invention the overall code has the property that the respective channel bit sequences that are encoded from the same message-bit sequence, starting from any possible state of the finite-state-machine, for each of the two values of a DC-control bit, that is part of a given user word have opposite parities for the sequences generated from the starting state up to the state where both encoder paths merge. For the case that the encoder paths do not merge, there is no such constraint. Finally, a new d=1, k=10 sliding-block decodable RLL code is disclosed with the following properties: (i) it has an r=2 constraint which is the lowest MTR value that is compatible with a rate R=⅔; (ii) it enables practical SISO-RLL decoding because of its compact 2-to-3 mapping; and (iii) the new code uses a parity-complementary word assignment4 (PCWA) for DC-control.
A method of converting a user bitstream into a coded bitstream by means of an overall channel code comprising the steps of
A coder for converting a user bitstream into a coded bitstream by means of an overall channel code by converting M-bit information words into N-bit code words, the coder comprising sub-coders repeated in a cyclical order with a predetermined repeat period, each sub-coder using a sub-code, wherein each sub-coder is arranged to receive mi-bit information words, where mi is an integer characteristic for each of the sub-codes, and is arranged to convert the received mi-bit information words into ni-bit code words, where ni is an integer characteristic for each of the sub-codes, and where for each sub-code, said characteristic integer number ni is greater than said characteristic integer number mi, such that the sum of the mi-numbers of all sub-codes within said repeat period equals M, and that the sum of the ni-numbers of all sub-codes within said repeat period equals N, where for each sub-code, its ni-bit code words are divided into a number of Tmax different code-word types and arranging its ni-bit code words into Tmax coding classes of coding states such that, for a given sub-code, an ni-bit code word of type t, where t is an integer number between 1 and Tmax, can be concatenated into a concatenated set of code words thus generating said coded bitstream and realizing said N-bit code-words of said overall channel code, with an ni+1-bit code word of the next sub-code if said subsequent code word of said next sub-code belongs to one of coding states of the coding class with index Tmax+1−t, and:
Dependencies are inferred from the claim text.