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Coding modulation method for multiuser transmission-oriented subcarrier variable system

A coding modulation and subcarrier technology, which is applied in the field of digital communication transmission technology and channel coding, can solve the problem of poor transmission efficiency of frequency-limited subcarriers, and achieve the effect of efficient transmission

Active Publication Date: 2016-10-12
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example: power line communication transmission system (Power Line Communication, PLC), within the bandwidth of OFDM system, the transmission efficiency of limited frequency band sub-carrier is poor

Method used

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  • Coding modulation method for multiuser transmission-oriented subcarrier variable system
  • Coding modulation method for multiuser transmission-oriented subcarrier variable system
  • Coding modulation method for multiuser transmission-oriented subcarrier variable system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0097] This coded modulation scheme provides a channel coding scheme as follows:

[0098] Provide QC-LDPC codes with four code rates of 0.2, 0.4, 0.6, and 0.8; the QC-LDPC code set is shown in the following table:

[0099]

[0100] Table 7 QC-LDPC code set table

[0101] The LDPC code used in the provided channel coding scheme performs bit truncation on the coded bits, which can still maintain good performance and can better adapt to the transmission scenario of the variable subcarrier system.

Embodiment 2

[0103] Take the transmission situation of 2 users as an example:

[0104] User 1:

[0105] S11: Select a QC-LDPC code with a code rate of 0.6 and a code length of 7680 to perform channel coding. Channel coding is performed on 4608 information bits to obtain 7680 coded bits.

[0106] S12: Perform bit truncation on 7680 coded bits to generate 7632 valid bits.

[0107] S13: Perform row-column transformation on 7632 effective bits to obtain a bit set with 318 rows and 24 columns.

[0108] S14: Perform the following operations on the 24 bits of each row:

[0109] Divide the 24 bits of each row from 1 to 100 into 4 groups, each group has 6 bits, and the 6 bits in the group are bit-replaced according to the bit-replacement pattern;

[0110] Divide the 24 bits of each row from 101 to 200 into 6 groups, each group has 4 bits, and the 4 bits in the group are bit-replaced according to the bit-replacement pattern;

[0111] The 24 bits in each row of rows 201 to 318 are divided into 2...

Embodiment 3

[0122] In this embodiment, the total number of subcarriers is 2048, the number of effective subcarriers is 2000, and the number of invalid subcarriers is 48. The subcarrier mapping pattern is shown in the table below:

[0123]

[0124] Table 8 Subcarrier mapping pattern table

[0125] Constellation mapping is performed on 15264 valid transmission bits.

[0126] The 15264 effective transmission bits are subjected to constellation mapping according to the constellation mapping pattern to obtain 2048 effective transmission symbols. Constellation map like Figure 6 shown.

[0127] Due to the different channel conditions of the effective subcarriers, the constellation symbols corresponding to subcarriers with good channel conditions use relatively high-order constellation diagrams; the constellation symbols corresponding to subcarriers with poor channel conditions use relatively low-order constellation diagrams; considering the constellation For the complexity of mapping and...

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Abstract

The invention discloses a coding modulation method for a multiuser transmission-oriented subcarrier variable system. The coding modulation method comprises the following steps of: for information bits of various users, performing channel coding, bit truncation and bit mapping to obtain bits to be transmitted of various users; according to a bit aggregation pattern, performing bit aggregation on the bits to be transmitted of various users so as to obtain aggregated bits; according to a constellation mapping pattern, performing constellation mapping on the aggregated bits so as to obtain constellation symbols to be transmitted; and modulating the constellation symbols to be transmitted to all sub-carriers, performing zero setting on the constellation symbols on unusable sub-carriers according to a sub-carrier mapping table, and subsequently performing modulation so as to obtain signals to be transmitted. The coding modulation method disclosed by the invention has the advantages that: fixed block coding to sub-carrier mapping adaptation is realized; and the sub-carriers with relatively high transmission efficiency are effectively utilized, so that high-efficiency transmission is realized.

Description

technical field [0001] The invention relates to the field of digital communication transmission technology and channel coding, in particular to a coding modulation method and coding modulation system for multi-user transmission-oriented subcarrier variable system. Background technique [0002] Quasi-Cyclic (QC)-LDPC code is an important subclass of LDPC code. It has a parity check matrix of a block-structured quasi-cyclic array, which is easy to design. The decoder can adopt a semi-parallel structure so that the hardware implementation is relatively simple and convenient. At the same time, it can also provide the same error control performance compared with general LDPC codes. Therefore, QC-LDPC codes have been adopted by multiple communication standards, such as IEEE 802.16e, IEEE802.11n, ITU-T G.hn, and DTMB. In addition, the LDPC codes used by DVB-T2 / S2 undergo row-swapping and column-swapping After that, it is also a QC-LDPC code. [0003] As shown in Equation 1, the p...

Claims

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Application Information

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IPC IPC(8): H04L27/34
CPCH04L27/3433H04L27/3483
Inventor 彭克武刘玥杨昉马旭宋健
Owner TSINGHUA UNIV
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