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ldpc encoder and encoding method in cmmb based on block-column cycle

An LDPC code and encoder technology, applied in the field of efficient implementation of LDPC encoders, can solve problems such as high cost, high power consumption, and large storage capacity.

Inactive Publication Date: 2015-10-28
RONGCHENG DINGTONG ELECTRONICS INFORMATION SCI & TECH CO LTD
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  • Claims
  • Application Information

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Problems solved by technology

[0004] Existing CMMB LDPC coders generally use the LU decomposition coding algorithm or RU coding algorithm (also known as the approximate lower triangular coding algorithm) suitable for general LDPC codes, which divides H into multiple isolated sub-matrices, which is not reasonable Utilizing H's block-column cycle characteristics and the same column weight characteristics, resulting in large storage capacity, high cost, and high power consumption

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  • ldpc encoder and encoding method in cmmb based on block-column cycle

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Embodiment Construction

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

[0021] A regular LDPC code can be defined by a parameter set (n, ρ, λ), where n is the code length, ρ and λ are the row weight and column weight of the parity check matrix H, respectively. The LDPC code satisfies the following relationship:

[0022] Hc T =0 (1)

[0023] where superscript T Indicates the transpose, 0 is an all-zero vector (or matrix), and c is the following 1×n order codeword

[0024] c=[c i ] (2)

[0025] Among them, 0≤i

[0026] For LDPC codes in systematic form, H can be transformed into figure 1 The approximate lower triangular shape H shown ALT . In the figure, k is the number of information bits, r is the number of parity bits, and they satisfy k+r=n. It can be seen from the figure that the H ALT Divided vertically into 4 parts

[0...

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Abstract

The invention provides an encoding scheme of LDPC (low-density parity-check) codes with two code rates in a CMMB (China mobile multimedia broadcasting) system. The encoding scheme is characterized in that an LDPC encoder of the system mainly comprises a controller, a vector storer, a resequencing table, a high-density matrix table, a rectangular array mapping table, a first block column expansion table, an address generator, a resequencing unit, a longitudinal accumulation unit and a parallel accumulation unit. The encoder is high in encoding step consistency and easy to implement. The encoder takes full advantages of the block column circulating characteristics and same column weight characteristics of a check matrix, is capable of effectively lowering requirements for the storer and logical resources without decreasing encoding speed and has the advantages of low cost, low power consumption and the like.

Description

technical field [0001] The invention relates to the field of mobile multimedia broadcasting, in particular to an efficient implementation method of an LDPC encoder in a CMMB system. Background technique [0002] Since various distortions and noises in the transmission channel will interfere with the transmitted signal, bit errors in the digital signal will inevitably occur at the receiving end. In order to reduce the bit error rate, channel coding technology needs to be adopted. Low-Density Parity-Check (Low-Density Parity-Check, LDPC) codes have become a research hotspot in the field of channel coding because of their excellent performance close to the Shannon limit and high-speed parallel decoding. [0003] The CMMB standard adopts binary LDPC regular codes with two code rates of 1 / 2 and 3 / 4. They are all systematic codes, but the information vectors are not concentrated in the first half or the second half of the codeword intact, but are scattered in the codeword. The ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M13/11
Inventor 张燕
Owner RONGCHENG DINGTONG ELECTRONICS INFORMATION SCI & TECH CO LTD