Hard decision guided forward and backward estimating method for estimating synchronization erroneous position

Abstract

The invention discloses a hard decision guided forward and backward estimating method for estimating a synchronization erroneous position and belongs to the field of digital communication error control coding. The method is characterized in that a hard decision estimated sequence output by an outer decoder is introduced into a reverse concatenated code inner decoder; the reference sequence of the inner decoder uses the XOR of a watermark sequence and an interlaced hard decision estimated sequence. The forward and backward estimating method computes output probability by using the reference sequence and an updated valid replacement error probability, and is further used for computing forward measurement value and a backward measurement value, and increases the reliability of the likelihood information of each bit output by the forward and backward estimating method. Compared with a reverse concatenated code conventional decoding method, the forward and backward estimating method is increased in accuracy and acquires higher performance gain with lower extra complexity.

Description

technical field [0001] The invention relates to the field of digital communication error control coding, in particular to a hard decision-oriented forward and backward estimation method for estimating the position of a synchronization error. Background technique [0002] In digital communication systems, synchronization is an important condition for the reliable transmission of information. At present, most digital communication systems use retransmission to solve the problem of synchronization loss. With the increasingly stringent requirements for synchronization in modern communication systems, encoding and decoding schemes that can correct synchronization errors have attracted extensive attention. Due to the memory of the channel disturbed by synchronization errors, a single uncorrected synchronization error will trigger a series of sudden substitution errors, resulting in catastrophic error propagation, which is suitable for traditional error correction codes with memor...

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Problems solved by technology

[0006] The traditional inverse concatenated code scheme reduces the decoding complexity, but the loss of decoding performance is greater. When the overall code rate of the inverse concatenated code is the same as that of the original concatenated code, the lower the code rate of the LDPC code is, the reverse The performance loss of the converted concatenated code is more serious than that of the original concatenated code

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