Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

A Soft Demodulation Method of Quadrature Amplitude Modulation

A technology of quadrature amplitude modulation and soft demodulation, applied in the field of communication, can solve the problem that the accuracy of soft demodulation information and storage capacity are difficult to achieve a good balance

Active Publication Date: 2017-04-19
NATIONZ TECH INC
View PDF2 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention provides a QAM soft demodulation method, which solves the problem that it is difficult to achieve a better balance between the accuracy of soft demodulation information and storage capacity in the prior art

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A Soft Demodulation Method of Quadrature Amplitude Modulation
  • A Soft Demodulation Method of Quadrature Amplitude Modulation
  • A Soft Demodulation Method of Quadrature Amplitude Modulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0020] The soft mapping method of QAM can be deduced as follows: mark time k, bit set {u k,i}, i=1,2,3...m is mapped to the real number pair {A of the constellation mapping plane k ,B k}, and the in-phase branch and quadrature branch X of the demodulator receiving data k , Y k It can be expressed as:

[0021] x k =a k A k +NI k Y k =a k B k +NQ k

[0022] where a k It is a Rayleigh random variable under Rayleigh fading channel and 1 under Gaussian white noise channel.

[0023] Among them, NI k and NQ k is the mean is 0 and the variance is Gaussian noise, and they are independent of each other.

[0024] Then the soft output of each bit, that is, the logarithmic likelihood ratio LLR (Logarithm of Likelihood Ratio) is:

[0025]

[0026] Using Bayesian criterion, and since P{u k,i =1}=P{u k,i =0}, the above formula gets:

[0027]

[0028] If the divisor of the QAM mapping is an even power of 2, the in-phase signal X n and the quadrature signal Y n In...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a flexible demodulation method for orthogonal amplitude modulation. The method includes the steps of figuring out an approximate flexible modulation output value LLRapproximate, obtained after demodulation, of each bit according to the real part Rdata or the imaginary part Idata of data to be demodulated, looking up a preset lookup table to find a flexible demodulation modification value LLRD-Normalized of each bit, and figuring out a final flexible demodulation output value LLROutput of each bit according to the approximate flexible modulation output value LLRapproximate of each bit and the flexible demodulation modification value LLRD-Normalized of each bit. According to the technical scheme, a perfect flexible demodulation method of a QAM is provided.

Description

technical field [0001] The invention relates to the communication field, in particular to a soft demodulation method of Quadrature Amplitude Modulation (QAM). Background technique [0002] QAM is a signal modulation method widely used in communication systems in recent years. In the modulation process, QAM uses the amplitude and phase of the carrier signal to represent different digital bit codes at the same time, and combines the multi-ary system with the orthogonal carrier technology to greatly improve the frequency band utilization. For example, China Mobile Multimedia Broadcasting (CMMB), a mobile TV industry standard officially promulgated by the State Administration of Radio, Film and Television in 2006, adopts a 16QAM modulation method. [0003] When demodulating data at the receiving end, commonly used QAM demodulation methods include hard demodulation and soft demodulation. Hard demodulation is to force the judgment of constellation points into corresponding modul...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/38
Inventor 陈烽
Owner NATIONZ TECH INC
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com