Patent No. | 9,075,738 |
---|---|

Issue Date | July 07, 2015 |

Title | Efficient Ldpc Codes |

Inventorship | Micha Anholt, Tel Aviv (IL) Naftali Sommer, Rishon Lezion (IL) Tal Inbar, Hod-Hasharon (IL) |

Assignee | Apple Inc., Cupertino, CA (US) |

6. A method, comprising:

initializing a decoder with a first Error Correction Code (ECC), wherein the first ECC is defined by a first set of parity

equations;

receiving a plurality of input code words, wherein each input code word of the plurality of input code words is encoded with

a second ECC, wherein the second ECC is defined by a second set of parity equations, wherein the second set of parity equations

is a proper subset of the first set of parity equations;

receiving an indication of which parity equations are included in the first set of parity equations but excluded from the

second set of parity equations;

and

decoding, iteratively, each input code word of the received plurality of input code words based upon messages transferred

between the symbol node memory and the check node memory, wherein the messages transferred between the symbol node memory

and the check node memory are controlled such that messages originating from check nodes that correspond to parity check equations

excluded from the second set of parity equations are prevented from affecting the symbol nodes by assigning to symbol nodes

respective artificial confidence metrics that indicate a zero value with a maximal likelihood based upon the received indication

of the parity equations included in the first set of parity equations but excluded from the second set of parity equations.

initializing a decoder with a first Error Correction Code (ECC), wherein the first ECC is defined by a first set of parity

equations;

receiving a plurality of input code words, wherein each input code word of the plurality of input code words is encoded with

a second ECC, wherein the second ECC is defined by a second set of parity equations, wherein the second set of parity equations

is a proper subset of the first set of parity equations;

receiving an indication of which parity equations are included in the first set of parity equations but excluded from the

second set of parity equations;

and

decoding, iteratively, each input code word of the received plurality of input code words based upon messages transferred

between the symbol node memory and the check node memory, wherein the messages transferred between the symbol node memory

and the check node memory are controlled such that messages originating from check nodes that correspond to parity check equations

excluded from the second set of parity equations are prevented from affecting the symbol nodes by assigning to symbol nodes

respective artificial confidence metrics that indicate a zero value with a maximal likelihood based upon the received indication

of the parity equations included in the first set of parity equations but excluded from the second set of parity equations.