Patent ID: 9564927
Date: 2017-02-07
CPC Classifications: H03M

Claim:
1. A communications apparatus, comprising: an outer encoder configured to transform a sequence of input bits to a sequence of outer encoded bits, wherein the sequence of outer-encoded bits is encoded in accordance with an outer code that is a member of the group consisting of a block code and a non- recursive convolutional code; a constrained interleaver that is configured to implement a permutation function to permute the order of the outer-encoded bits to produce a constrained-interleaved sequence of outer-encoded bits, wherein the permutation function implements a pseudo -random reordering of the outer-encoded bits subject to the at least one SRCI constraint; an inner encoder configured to transform the constrained-interleaved sequence of outer-encoded bits to a sequence of inner-encoded bits, wherein the sequence of inner -encoded bits is encoded in accordance with an inner code; and whereby the sequence of inner-encoded bits constitutes a serially-concatenated sequence of bits that incorporates coding from both the inner code and the outer code in accordance with a serially-concatenated code that achieves a target minimum distance of d wherein the constrained interleaver implements at least one SRCI (single row constrained interleaver) constraint that prevents one or more low-distance error sequences from occurring in the serially-concatenated code; wherein the outer code has a minimum distance of d wherein the permutation function implemented by the constrained interleaver is configured to implement the at least one SRCI constraint in order to enforce d wherein the at least one SRCI constraint includes at least one first SRCI constraint that ensures that the permutation function does not place any respective index from the integer ring [0,K-1] into any position in a permuted integer ring π[ ,K-1] that corresponds to any identified respective restricted zone, where each identified respective restricted zone corresponds to a subset of one or more adjacent positions in π[0,K-1] that, if the respective index were to be placed into any one of the identified respective restricted zones, at least one error sequence of weight less than d