Patent ID: 6591390
Filing Date: 2003-07-08
Classification: H03M

Abstract:
A method of iteratively decoding a sequence of received signals, representative of systematic convolutional encoded elements generated by a parallel-concatenated encoder from a source of original digital data elements, into decoded elements corresponding to the original digital data elements, the method comprising the steps of:(a) probability-based decoding a received input information sequence x(k), a first received convolutional code sequence Y(k) corresponding to the input information sequence, and a first a priori information sequence to generate a first extrinsic information sequence; (b) probability-based decoding an interleaved received input information sequence Xâ€²(k), a second received convolutional code sequence Yâ€²(k) corresponding to the interleaved input information sequence, and a second a priori information sequence to generate a second extrinsic information sequence; (c) summing the first a priori information sequence and the first extrinsic information sequence to generate a first reference sequence; (d) quantizing the first reference sequence to generate a first quantized reference sequence; (e) summing the second a priori information sequence and the second extrinsic information sequence to generate a second reference sequence; (f) quantizing the second reference sequence to generate a second quantized reference sequence; (g) CRC encoding the first quantized reference sequence to generate a first CRC word; (h) CRC encoding the second quantized reference sequence to generate a second CRC word; (i) storing the first CRC word and the second CRC word; (j) probability-based decoding both a new first a priori information sequence and a new second a priori information sequence to generate a new first extrinsic information sequence and a new second extrinsic information sequence; (k) repeating steps (c) through (h) using the new information sequences generated in step (j) to generate a new first CRC word and a new second CRC word; (l) comparing the new first CRC word with the stored first CRC word and the new second CRC word with the stored second CRC word to determine if the stored CRC words are identical with the newly generated CRC words; (m) repeating steps (i) through (l) using the new first CRC word and the new second CRC word until the compared CRC words are identical; and (n) generating substantially error-free decoded elements when the compared CRC words are identical.