High-order coded modulation method based on low density check code

A technology of low-density parity check code and coded modulation, applied in the field of high-order coded modulation, which can solve problems such as uncertainty, not being accurate, and not being able to analyze the UEP characteristics of regular LDPC codes

Inactive Publication Date: 2007-09-26
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above method obviously cannot accurately reflect the geometric topology of the bipartite graph of the LDPC code
Therefore, although the above method can reflect the unequal error protection (UEP) characteristics of LDPC codes to a certain extent, this method is not an accurate meth

Method used

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  • High-order coded modulation method based on low density check code
  • High-order coded modulation method based on low density check code
  • High-order coded modulation method based on low density check code

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Embodiment 1

[0055] Fig. 8 shows a schematic diagram of a high-order modulation method of a general LDPC code. First, assume that the high-order modulation is m-order, that is, consists of m bits (a 1 …a m ) to select a modulation symbol on the constellation diagram, and set a 1 to a m are sorted from strong to weak. The source data block S is encoded by LDPC to obtain the encoded data block U, and the protection ability of each bit of the encoded data block is sorted from small to large to obtain the sorted data block V. The protection capability here is equivalent to the protection level of each bit defined in [Document 27] mentioned above, and a fixed sorting table can be calculated in advance, and each sorting is equivalent to an interleaving operation. Divide the sorted data block V equally into m sorted sub-data blocks, V={V 1 , V 2 ,...,V m ) (if V is not divisible by m, coded bits with no real meaning (all 1 or all 0 or other appropriate bit sequences) can be added appropria...

Embodiment 2

[0058] In practical application, high-order modulation usually adopts the way of I / Q channel symmetrical modulation. For 16QAM shown in Figure 2 and 64QAM shown in Figure 3, the Gray mapping used by the I and Q paths is the same. Without loss of generality, it is assumed that in the m-order high-order modulation, the I channel adopts bits, while the Q way uses bits, from a 1 arrive in order from strong to weak, and with is perfectly symmetrical. Therefore, the high-order modulation bits in the symmetrical mode have levels.

[0059] Figure 9 shows the high-order modulation method of the LDPC code with symmetrical I / Q modulation. The source data block S is encoded by LDPC to obtain the encoded data block U, and the protection ability of each bit of the encoded data block is sorted from small to large to obtain the sorted data block V. A fixed sorting table can be calculated and obtained in advance, and each sorting is equivalent to an interleaving operation. Di...

Embodiment 3

[0061] Embodiment 3 FIG. 10 is a high-order modulation method of LDPC code modulated by 16QAM. 16QAM adopts the constellation mapping diagram of 16QAM Gray (Golay) coding shown in FIG. 2 . The source data block S is encoded by LDPC to obtain the encoded data block U, and the protection ability of each bit of the encoded data block is sorted from small to large to obtain the sorted data block V. A fixed sorting table can be calculated and obtained in advance, and each sorting is equivalent to an interleaving operation. Divide the sorted data block V into 2 sorted sub-blocks equally, V={V 1 , V 2}. Among them, V 1 is a data block with low protection ability, and V 2 It is a data block with high protection capability. Each sorted sub-data block undergoes serial-to-parallel conversion, and then performs its own interleaving to obtain the interleaved sub-data block W 1 and W 2 . The interleaving here should ensure that the bits belonging to the same parity formula are plac...

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Abstract

The high-order code modulating method based on LDPC code comprises: mapping the bit with lower/higher protective capacity in LDPC code to the strong/weak bit with lower/higher error in high-order modulation; specially, mapping the bit with least coincident code in LDPC into the strongest bit in high-order modulation. This invention can improve bit error rate performance in high SNR internal.

Description

technical field [0001] The invention relates to a high-order coding and modulation technology of a low-density parity check code (LDPC code (LowDensity Parity Code)) for channel error correction in the communication field. In particular, it relates to high-order coded modulation methods based on low-density check codes. Background technique [0002] LDPC code is a powerful forward error correction coding method rediscovered in the past ten years. It has approached the Shannon limit under the condition of long code construction, so it is considered to be an effective replacement technology for Turbo code, and it is likely to be used in A generation of mobile communications and deep space communications. Figure 1 shows a simple example of using a bipartite graph to represent a low density check code. LDPC code is a kind of linear block code based on sparse parity check matrix. In 1981, Tanner proposed to use a bipartite graph to represent a low-density linear block code. Si...

Claims

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Application Information

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IPC IPC(8): H04L27/00H04L1/00
CPCH04L1/0041H03M13/255H04L1/0071H03M13/11H04L27/3416H04L2001/0098H04L27/34H04L27/3488H04L1/0057
Inventor 吴湛击李继峰
Owner PANASONIC CORP
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