CommPy

CommPy is an open source toolkit implementing digital communications algorithms in Python using NumPy and SciPy.

Objectives

• To provide readable and useable implementations of algorithms used in the research, design and implementation of digital communication systems.

Available Features

Channel Coding

• Encoder for Convolutional Codes (Polynomial, Recursive Systematic). Supports all rates and puncture matrices.
• Viterbi Decoder for Convolutional Codes (Hard Decision Output).
• MAP Decoder for Convolutional Codes (Based on the BCJR algorithm).
• Encoder for a rate-1/3 systematic parallel concatenated Turbo Code.
• Turbo Decoder for a rate-1/3 systematic parallel concatenated turbo code (Based on the MAP decoder/BCJR algorithm).
• Binary Galois Field GF(2^m) with minimal polynomials and cyclotomic cosets.
• Create all possible generator polynomials for a (n,k) cyclic code.
• Random Interleavers and De-interleavers.
• Belief Propagation (BP) Decoder and triangular systematic encoder for LDPC Codes.

Channel Models

• SISO Channel with Rayleigh or Rician fading.
• MIMO Channel with Rayleigh or Rician fading.
• Binary Erasure Channel (BEC)
• Binary Symmetric Channel (BSC)
• Binary AWGN Channel (BAWGNC)

Wifi 802.11 Simulation Class

• A class to simulate the transmissions and receiving parameters of physical layer 802.11 (currently till VHT (ac)).

Filters

• Rectangular
• Raised Cosine (RC), Root Raised Cosine (RRC)
• Gaussian

Impairments

• Carrier Frequency Offset (CFO)

Modulation/Demodulation

• Phase Shift Keying (PSK)
• Quadrature Amplitude Modulation (QAM)
• OFDM Tx/Rx signal processing
• MIMO Maximum Likelihood (ML) Detection.
• MIMO K-best Schnorr-Euchner Detection.
• MIMO Best-First Detection.
• Convert channel matrix to Bit-level representation.
• Computation of LogLikelihood ratio using max-log approximation.

Sequences

• PN Sequence
• Zadoff-Chu (ZC) Sequence

Utilities

• Decimal to bit-array, bit-array to decimal.
• Hamming distance, Euclidean distance.
• Upsample
• Power of a discrete-time signal

Links

• Estimate the BER performance of a link model with Monte Carlo simulation.
• Link model object.
• Helper function for MIMO Iteration Detection and Decoding scheme.

FAQs

Why are you developing this?

During my coursework in communication theory and systems at UCSD, I realized that the best way to actually learn and understand the theory is to try and implement ''the Math'' in practice :). Having used Scipy before, I thought there should be a similar package for Digital Communications in Python. This is a start!

What programming languages do you use?

CommPy uses Python as its base programming language and python packages like NumPy, SciPy and Matplotlib.

How can I contribute?

Implement any feature you want and send me a pull request :). If you want to suggest new features or discuss anything related to CommPy, please get in touch with me (veeresht@gmail.com).

How do I use CommPy?

Requirements/Dependencies

• python 3.2 or above
• numpy 1.10 or above
• scipy 0.15 or above
• matplotlib 1.4 or above
• nose 1.3 or above
• sympy 1.7 or above

Installation

• To use the released version on PyPi, use pip to install as follows::

$ pip install scikit-commpy

• To work with the development branch, clone from github and install as follows::

$ git clone https://github.com/veeresht/CommPy.git
$ cd CommPy
$ python setup.py install

• conda version is curently outdated but v0.3 is still available using::

$ conda install -c https://conda.binstar.org/veeresht scikit-commpy

Citing CommPy

If you use CommPy for a publication, presentation or a demo, a citation would be greatly appreciated. A citation example is presented here and we suggest to had the revision or version number and the date:

V. Taranalli, B. Trotobas, and contributors, "CommPy: Digital Communication with Python". [Online]. Available: github.com/veeresht/CommPy

I would also greatly appreciate your feedback if you have found CommPy useful. Just send me a mail: veeresht@gmail.com

For more details on CommPy, please visit https://veeresht.info/CommPy/