Code Monkey home page Code Monkey logo

density-evolution-awgn's Introduction

Density-Evolution-AWGN

  1. main.m at subfolder https://github.com/Lcrypto/Density-Evolution-AWGN/tree/master/%20Reciprocal-channel%20approximation%20for%20approximation%20of%20Density%20Evolution%20Iterative%20Decoding%20Threshold contain protograph reciprocal-channel approximation (RCA) for GA like approximation of Density Evolution Iterative Decoding Threshold of Multi Edge Type (MET) LDPC Codes. Using RCA constructed codes from article S.-Y.Chung G.D. Forney, T.J. Richardson, R. Urbanke On the design of low-density parity-check codes within 0.0045 dB of the Shannon limit, IEEE Communications letters 5 (2), 58-60, 2001. RCA method in detail described at S.-Y.Chung,“On the construction of some capacity-approaching coding schemes,” Ph.D. dissertation, MIT, Cambridge, MA, 2000. Tested on old (2011) and new version (2018) of Matlab and GNU Octave 5.1 (several times slower than Matlab). RCA-GA is one of the best method for fast DE approximation from runtime and accuracy. Protograph RCA not require to generate protograph, lift it directly using Simulated Annealing with girth/EMD (https://github.com/Lcrypto/Simulated-annealing-lifting-QC-LDPC) or another QC extension methods.

  2. profgen.m - Density evolution based optimization of degree distribution for LDPC codes under AWGN-channel. Taked from https://www.ece.rice.edu/~debaynas/codes.html Alexandre de Baynast. Due to changes at lsqlin implementation work till R2016(active-set algorithm removed). New version of matlab currently not support. Thank to Dr. Ovinnikov A. for bug report.

  3. main.m at subfolder GA - contain Gaussian approximation based Differential Evolution optimization of LDPC Degree distribution from Dr. Chén Zǐ Qiáng (陈紫强), Guilin University of Electronic Technology (桂林电子科技大学,广西桂).

Very good compare of quality of GA, GA-RCA and Pure DE at paper Sarah J. Johnson, et al "A New Density Evolution Approximation for LDPC and Multi-Edge Type LDPC Codes," in IEEE Transactions on Communications, vol. 64, no. 10, pp. 4044-4056, Oct. 2016, https://arxiv.org/pdf/1605.04665.pdf.

  1. Add draft version of Covariance Evolution with Octopus protograph, as generalization of Density Evolution on Finite-Length https://github.com/Lcrypto/Density-Evolution-AWGN/tree/master/Covariance-Evolution. In Dr. Richardson file store tabulated values: a,b,VN,CN,Circulant and calculate WER(SNR) = Q(a*(10*log10(SNR)-b)). Using linear interpolation get values for circulant between and calculate WER for them.

To get protograph from protograph ensemble (weight profile: weight distribution, rho/lambda) use:

  1. rand_proto.m - generate protograph according to weight distribution of variable and check. Algorithm probabalistical, can fail. Start script again several time (from 10 to 100K) or use different size of protograph and degree distibution.

  2. PEG https://github.com/Lcrypto/classic-PEG-

To lift protograph for certain circulant use:

  1. Simulated Annealing with girth/EMD - current state of the art lifting method for optimization of graph properties https://github.com/Lcrypto/Simulated-annealing-lifting-QC-LDPC
  2. To compare you can try Fossorier's approach Guess-and-Test:

https://github.com/Lcrypto/Guess-and-Test-For-CPM-weight-more-1

and

https://github.com/Lcrypto/-Greedy-Guess-and-Test-method-for-construction-QC-LDPC-codes-with-CPM-of-weigth-more-than-1.

density-evolution-awgn's People

Recommend Projects

  • React photo React

    A declarative, efficient, and flexible JavaScript library for building user interfaces.

  • Vue.js photo Vue.js

    🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.

  • Typescript photo Typescript

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

  • TensorFlow photo TensorFlow

    An Open Source Machine Learning Framework for Everyone

  • Django photo Django

    The Web framework for perfectionists with deadlines.

  • D3 photo D3

    Bring data to life with SVG, Canvas and HTML. 📊📈🎉

Recommend Topics

  • javascript

    JavaScript (JS) is a lightweight interpreted programming language with first-class functions.

  • web

    Some thing interesting about web. New door for the world.

  • server

    A server is a program made to process requests and deliver data to clients.

  • Machine learning

    Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.

  • Game

    Some thing interesting about game, make everyone happy.

Recommend Org

  • Facebook photo Facebook

    We are working to build community through open source technology. NB: members must have two-factor auth.

  • Microsoft photo Microsoft

    Open source projects and samples from Microsoft.

  • Google photo Google

    Google ❤️ Open Source for everyone.

  • D3 photo D3

    Data-Driven Documents codes.