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Method for softly demodulating Gray-mapping pulse amplitude modulation (PAM) signal

A technology of gray mapping and soft demodulation, applied in digital transmission system, electrical components, error prevention, etc.

Inactive Publication Date: 2012-04-18
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] Although the approximation method omits the exponent operation, it still needs to calculate the Euclidean distance to all constellation points and take the minimum value

Method used

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  • Method for softly demodulating Gray-mapping pulse amplitude modulation (PAM) signal
  • Method for softly demodulating Gray-mapping pulse amplitude modulation (PAM) signal
  • Method for softly demodulating Gray-mapping pulse amplitude modulation (PAM) signal

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Embodiment Construction

[0025] The implementation method of this patent is described below by taking the gray mapping 8-PAM signal as an example.

[0026] The sender divides the bits to be sent into groups of 3, and set these 3 bits as b 0 , b 1 , b 2 , align them according to figure 1 The manner shown is mapped to the corresponding constellation and sent out. Suppose the signal received by the receiver is r. then b 0 , b 1 , b 2 The corresponding soft information can be extracted according to the following rules.

[0027] b 0 Calculation of soft information:

[0028] h 0 = r

[0029] Λ 0 ( r ) = 1 σ 2 sgn ( h 0 ) ( | h 0 | + ...

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Abstract

The invention provides a method for softly demodulating a Gray-mapping pulse amplitude modulation (PAM) signal. The method comprises the following steps of: converting soft information between second-highest-bit soft information and lowest-bit soft information into highest-bit soft information; and calculating the highest-bit soft information by using a nonlinear approximation function.

Description

technical field [0001] The invention relates to the field of computer and communication, in particular to a soft demodulation method of Gray mapping PAM signal. Background technique [0002] PAM (Pulse Amplitude Modulation) is a commonly used modulation method in wireless communication. The Gray mapped constellation indicates that the mapped constellation is coded according to the Gray code, which ensures that the mapped constellation is symmetrical and that only one code element is different between adjacent constellation points. Compared with other constellations, the gray map constellation has a lower bit error rate for the same symbol error rate. [0003] In order to make full use of the information of the received signal for error correction decoding, the demodulator should provide the decoder with soft decision information that can reflect the probability of the received bit, generally using the log-likelihood ratio (LLR, Log-Likelihood Ratio) of the received bit To ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/00
Inventor 王磊徐大专汪自清
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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